Tropical Storm Nana

Tropical Storm Nana Track 2200 Hours September 3 2020
Tropical Storm Nana Track 2200 Hours September 3 2020

Tropical Storm Nana Wind Speed Field

Tropical Storm Nana – NWS National Hurricane Center Miami FL 1000 PM CDT Thu Sep 03, 2020 (see Thurs  video below)

Satellite and surface data indicate that Nana’s low-level circulation has dissipated over the mountainous terrain of southwestern Guatemala. Therefore, this will be the final NHC advisory on this system. The mid-level remnants are expected to emerge over the eastern Pacific waters near the Gulf of Tehuantepec later tonight or early Friday. The global models indicate that strong upper-level northeasterly flow will prevent re-development over the next couple of days.

However, this system could produce locally heavy rainfall along portions of the southeastern and southern coasts of Mexico over the weekend. Additional information on the remnants on Nana can be found in the eastern Pacific basin Tropical Weather Outlook.

FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 15.6N  92.0W   25 KT  30 MPH - Depression (WSWS La Mesilla, Guatemala)
 12H  04/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 400 PM CDT Thu Sep 03, 2020

Satellite imagery indicates that Nana continues to weaken over land, with only a small area of convection remaining near and to the south of the low-level center. It is estimated that Nana has weakened to a 30-kt tropical depression, although as with the last advisory there are no observations near the cyclone’s core and thus the estimate is rather uncertain. Continued weakening is expected, and Nana is likely to be a remnant low pressure area by the time it reaches the Gulf of Tehuantepec in 12-24 h. The global models continue to forecast conditions that are not conducive for Nana to re-intensify, so the intensity forecast calls for the remnant low to dissipate by 48 h even though it will be over water. There is a possibility that a low pressure area will re-form over the Pacific in association with the remnants of Nana late this weekend or early next week, but the chances of re-generation to a tropical cyclone appear low at this time.

The initial motion is 255/12 kt. A low- to mid-level ridge to the north of Nana should keep it moving on a westward to west-southwestward track during the remainder of the cyclone’s life. The new official forecast track is again similar to the previous track and lies near the various consensus models,

KEY MESSAGES:

  • 1. Heavy rainfall with isolated maximum amounts as high as 3 to 6 inches could result in flash flooding in Guatemala and portions of southeastern Mexico.
FORECAST POSITIONS AND MAX WINDS

INIT  03/2100Z 16.0N  91.1W   30 KT  35 MPH - Depression (WSW Los Angeles, Guatemala)
 12H  04/0600Z 15.5N  92.8W   25 KT  30 MPH - Depression (ENE Mapastepec, Mexico)
 24H  04/1800Z 15.0N  95.0W   20 KT  25 MPH - Low (ESE Puerto Arista, Mexico)
 36H  05/0600Z 14.7N  97.3W   20 KT  25 MPH - Low (ESE Puerto Escondido, Mexico)
 48H  05/1800Z...DISSIPATED

NWS National Hurricane Center Miami FL 1000 AM CDT Thu Sep 03, 2020 

Satellite imagery indicates that Nana is weakening rapidly as it crosses northern Guatemala. There are no available observations near the center, so the initial intensity estimate of 40 kt is rather uncertain. Continued weakening is expected, and Nana is likely to be a remnant low pressure area by the time it reaches the Gulf of Tehuantepec in about 24 h. The global models continue to forecast conditions that are not conducive for Nana to re-intensify, so the intensity forecast calls for the remnant low to dissipate by 48 h even though it will be over water. The initial motion is 260/13 kt. A low- to mid-level ridge to the north of Nana should keep it moving on a west to west-southwestward track during the remainder of the cyclone’s life. The new official forecast track is similar to the previous track and lies near the various consensus models,

KEY MESSAGES:

  • 1. Tropical storm conditions will continue near the center of Nana for a few more hours. 2. Heavy rainfall with isolated maximum amounts as high as 3 to 6 inches could result in flash flooding in Guatemala and portions of southeastern Mexico.
FORECAST POSITIONS AND MAX WINDS

INIT  03/1500Z 16.4N  90.3W   40 KT  45 MPH - Tropical Storm - (WNW Las Pozas, Guatemala)
 12H  04/0000Z 16.0N  92.0W   30 KT  35 MPH - Depression (WNW La Gloria, Mexico)
 24H  04/1200Z 15.4N  94.4W   25 KT  30 MPH - Low (WSW Puerto Arista, Mexico)
 36H  05/0000Z 14.9N  96.6W   20 KT  25 MPH - Low (WSW San Pedro Pochutla, Mexico)
 48H  05/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 1000 PM CDT Wed Sep 02, 2020 

After the center of Nana nearly became exposed during the late afternoon, a new burst of convection developed near and to the south of the center which has resulted in strengthening this evening. Very recently received data from an Air Force Reserve reconnaissance aircraft has indicated that Nana has become a hurricane. The plane has measured a peak 700-mb flight-level wind of 72 kt to the north of the center, and peak SFMR winds of 62 kt earlier this evening. These data support an initial intensity of 65 kt, making Nana the fifth hurricane of the 2020 Atlantic basin hurricane season.

Since Nana should make landfall along the coast of Belize within the next several hours, little additional strengthening is expected before the center crosses the coast. Rapid weakening will occur after landfall, and the new 12 through 36 hour intensity forecast reflects this. The low-level center is likely to dissipate over mountainous terrain within 48 hours, if not sooner. Nana is moving just south of due west at about 265/14 kt. A low- to mid-level ridge to the north of Nana should keep it moving on a west-southwestward motion during the next day or so. The guidance enveloped has shifted slightly southward and the new NHC track forecast has been adjusted accordingly.

KEY MESSAGES:

  • 1. Hurricane conditions and a dangerous storm surge will spread onshore along portions of the coast of Belize within the Hurricane Warning area through early Thursday.
  • 2. Tropical storm conditions are expected in the tropical storm warning areas in Belize, the Bay Islands, Guatemala, and the Yucatan Peninsula of Mexico through early Thursday. 3. Heavy rainfall with isolated maximum amounts as high as 8 to 12 inches could result in flash flooding in Belize, Guatemala, and portions of southeastern Mexico and the Yucatan Peninsula.
FORECAST POSITIONS AND MAX WINDS

INIT  03/0300Z 17.0N  87.5W   65 KT  75 MPH - Category 1 (ESE Mullins River, Belize)
 12H  03/1200Z 16.8N  89.2W   50 KT  60 MPH - Tropical Storm (ENE El Naranjo, Guatemala)
 24H  04/0000Z 16.4N  91.6W   30 KT  35 MPH - Depression (WSW Euseba, Mexico)
 36H  04/1200Z 16.0N  93.9W   20 KT  25 MPH - Low (WSW  Paredón, Mexico)
 48H  05/0000Z...DISSIPATED

NWS National Hurricane Center Miami FL 400 PM CDT Wed Sep 02, 2020 

Nana continues to feel the effects of about 15 kt of northerly vertical shear, as the low-level center is located near the northern edge of the main convective mass. Data from the last Air Force Reserve Hurricane Hunter Mission showed that the flight-level winds at 850 mb were a little lower than earlier. However, incomplete SFMR data suggested surface winds near 50 kt, and the aircraft reported that the central pressure is near 999 mb. The initial intensity is held at 50 kt, although this could be a little generous.

The initial motion is westward or 270/13 kt. A low- to mid-level ridge to the north of the cyclone is forecast to keep steering Nana toward the west, or maybe just south of west, for the remainder of the cyclone’s life. The new forecast track, which again is changed only slightly from the previous forecast, calls for the cyclone to pass north of the Bay Islands this evening, then make landfall over central or southern Belize in about 12-18 h.

Nana is running out of time to strengthen before landfall, and between that and the ongoing shear none of the intensity guidance forecasts it to become a hurricane before landfall. However, any strong convective burst could spin up the cyclone, and since the bursts have been frequent today the intensity forecast calls for Nana to strengthen to near hurricane strength at landfall. After landfall, steady weakening is expected. Several of the global models now show the remnants of Nana emerging over the Gulf of Tehuantepec in 48-60 h. However, these models continue to forecast dissipation even over water, so the forecast dissipation time is unchanged since the previous advisory.

KEY MESSAGES:

  • 1. Nana could bring hurricane conditions and dangerous storm surge tonight to portions of the coast of Belize, and a hurricane warning is in effect. Preparations to protect life and property should be rushed to completion.
  • 2. Tropical storm conditions are expected in the tropical storm warning areas in Belize, the Bay Islands, Guatemala, and the Yucatan Peninsula of Mexico by tonight.
  • 3. Heavy rainfall with isolated maximum amounts as high as 8 to 12 inches could result in flash flooding in Belize, Guatemala, and portions of southeastern Mexico and the Yucatan Peninsula.
FORECAST POSITIONS AND MAX WINDS

INIT  02/2100Z 17.0N  85.9W   50 KT  60 MPH - Tropical storm (ENE Tocoa, Honduras)
 12H  03/0600Z 16.8N  87.8W   60 KT  70 MPH - Tropical storm (ESE Hopkins, Belize)
 24H  03/1800Z 16.6N  90.1W   45 KT  50 MPH - Tropical storm (ESE  El Subin, Guatemala)
 36H  04/0600Z 16.4N  92.4W   30 KT  35 MPH - Depression (WNW Las Rosas, Mexico)
 48H  04/1800Z 16.2N  94.8W   20 KT  25 MPH - Low (ESE Santa María del Mar, Mexico)
 60H  05/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 500 AM EDT Wed Sep 02, 2020

Nana’s Central Dense Overcast has become a little better defined, with cloud tops to -80 deg C or colder. Upper-level outflow continues to be somewhat inhibited over the northern portion of the circulation. SFMR-observed surface winds and adjusted flight-level winds from an Air Force Hurricane Hunter aircraft indicated an intensity of 50 kt. Although northerly shear is likely to limit intensification, the environment is conducive enough for Nana to strengthen into a hurricane later today.

The official intensity forecast is close to the Decay-SHIPS prediction based on the ECMWF global model forecast fields. Center fixes from the aircraft indicate that the motion continues to be generally westward, or 270/16 kt, to the south of a strong mid-level high pressure area. Over the next couple of days, the ridge is expected to be maintained or to build a little more to the west. This should keep Nana on a westward or slightly south-of-west track until it moves into Central America. The official track forecast is close to the previous one and also very close to the latest Florida State University Superensemble prediction.

Observations from the aircraft and NOAA data buoy 42057 indicate that Nana is a rather small tropical cyclone, with tropical-storm-force winds extending 60 n mi or less from the center.

KEY MESSAGES:

  • 1. Tropical Storm Nana is forecast to be a hurricane as it approaches the coast, and interests in Honduras, Guatemala, Belize, and the Yucatan Peninsula should closely monitor the progress of this storm. Strong winds, dangerous storm surge and very heavy rainfall causing flash flooding are becoming more likely from Nana.
FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 17.0N  82.7W   50 KT  60 MPH - Tropial Storm (WSW Kingston, Jamaica)
 12H  02/1800Z 16.9N  85.0W   60 KT  70 MPH - Tropial Storm (ENE Tocoa, Honduras)
 24H  03/0600Z 16.8N  87.6W   65 KT  75 MPH - Category 1 (ESE Hopkins, Belize)
 36H  03/1800Z 16.5N  89.8W   50 KT  60 MPH - Tropial Storm (WSW El Chal, Guatemala)
 48H  04/0600Z 16.4N  92.1W   30 KT  35 MPH - Depression (WNW Yaluma, Mexico)
 60H  04/1800Z 16.1N  93.9W   20 KT  25 MPH - Low (ESE Villa del Mar, Mexico)
 72H  05/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 PM EDT Tue Sep 01, 2020

Deep convection redeveloped over the center of Nana during the late afternoon and recent microwave imagery has revealed a small, well-defined low-level eye-like feature, and convective banding around the southwestern portion of the circulation. An Air Force Reserve hurricane hunter aircraft that has provided a couple of center fixes within the past hour or two has measured a peak 850-mb flight-level wind of 62 kt, and believable SFMR winds of around 50 kt, which supports an initial intensity of 50 kt. Data from aircraft indicated that the minimum pressure is around 999 mb.

Nana is moving westward or 275/16 kt. A strong deep-layer ridge to the north of the tropical cyclone should steer it westward over the next day or so. After that time, the ridge is forecast to build west-southwestward and the dynamical models indicate that this will cause Nana to turn west-southwestward by Thursday. On this track, Nana is expected to approach the coast of Belize late Wednesday night or early Thursday, and move inland over Belize and Guatemala later that day. The track guidance is in good agreement on this scenario but has trended slightly southward, which seems reasonable given that Nana is vertically deep and is more likely to feel the deep-layered east-northeasterly flow. The new NHC track forecast is close to the FSU Superensemble and the HFIP corrected consensus model.

The tropical storm is currently within an environment of light to moderate northeasterly shear. This shear does not seem to be strong enough to prevent strengthening during the next 12-24 hours, and the NHC intensity forecast shows a slightly faster rate of intensification during that time. This is in agreement with the latest SHIPS model output and the HCCA and HWRF models, and calls for Nana to become a hurricane within 24 hours. The shear is forecast to become more northerly just before landfall, and this is likely to slow the intensification process. Rapid weakening is expected after landfall, and the low-level circulation is expected to dissipate over Guatemala or southeastern Mexico by day 3.

KEY MESSAGES:

  • Tropical Storm Nana is forecast to be a hurricane as it approaches the coast, and interests in Honduras, Guatemala, Belize, and Yucatan should closely monitor the progress of this storm. Strong winds, dangerous storm surge and very heavy rainfall causing flash flooding are becoming more likely from Nana.
FORECAST POSITIONS AND MAX WINDS

INIT  02/0300Z 17.0N  80.9W   50 KT  60 MPH - Tropical Storm (WSW Kingston, Jamaica)
 12H  02/1200Z 17.1N  83.5W   60 KT  70 MPH - Tropical Storm (WSW Kingston, Jamaica)
 24H  03/0000Z 17.0N  86.3W   65 KT  75 MPH - Category 1 (ENE Hopkikns, Belize)
 36H  03/1200Z 16.8N  88.6W   65 KT  75 MPH - Category 1 (Rancho Grande, Belize)
 48H  04/0000Z 16.5N  90.7W   35 KT  40 MPH - Tropical Storm (
 60H  04/1200Z 16.2N  93.1W   20 KT  25 MPH - Low (ENE Villa Corzo, Mexico)
 72H  05/0000Z...DISSIPATED

NWS National Hurricane Center Miami FL 500 PM EDT Tue Sep 01, 2020 

Although convection has waned somewhat since the previous advisory due to mid-level dry air entrainment, Nana still has enough deep convection over and surrounding the low-level center to keep the intensity at 45 kt. Upper-level outflow has continued to improve, with the associated anticyclone becoming more symmetrical. Another reconnaissance mission is scheduled for this evening.

The initial motion estimate is 275/16 kt. There are no significant changes to the previous track forecast or reasoning. A pronounced deep-layer to the north of Nana is forecast to remain intact and even build westward over the next few days, keeping Nana moving in a general westward direction for the next 36 hours or so. Thereafter, the aforementioned ridge is expected to build west-southwestward across southern Mexico, driving the cyclone west-southwestward as well across northern Central America. The new NHC forecast track is similar to the previous advisory track, and lies close to a blend of the simple consensus models TVCN and GFEX, and the corrected- consensus models NOAA-HCCA and FSSE.

The current northeasterly 15 kt of vertical wind shear and dry air intrusions should inhibit development for next 24 hours or so. However, the GFS and ECMWF models both forecast the shear to gradually decrease during the next 48 hours, becoming near 5 kt by 36 hours. The lower vertical shear, coupled with the already impressive outflow pattern, sea-surface temperatures of 29.5-30.5 deg C, and a moistening mid-level environment should allow for gradual strengthening for the next 24 hours, followed by more significant intensification thereafter, which will continue right up until landfall occurs. The NHC official intensity forecast is a blend of the simple consensus intensity model IVCN, and the corrected-consensus models NOAA-HCCA and FSSE.

A Tropical Storm Warning and Tropical Storm Watch have been issued for the southern portion of the Yucatan Peninsula and the Caribbean Sea coast of Guatemala, respectively.

KEY MESSAGES:

  • 1. Tropical Storm Nana is now forecast to be a hurricane as it approaches the coast, and interests in Honduras, Guatemala, Belize, and Yucatan should closely monitor the progress of this storm. Strong winds, dangerous storm surge and very heavy rainfall causing flash flooding are becoming more likely from Nana.
FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 16.8N  79.3W   45 KT  50 MPH - Tropical Storm (WSW Kingston, Jamaica)
 12H  02/0600Z 17.1N  81.5W   50 KT  60 MPH - Tropical Storm (WSW Kingston, Jamaica)
 24H  02/1800Z 17.3N  84.7W   55 KT  65 MPH - Tropical Storm (WSW Kingston, Jamaica)
 36H  03/0600Z 17.2N  87.3W   65 KT  75 MPH - Category 1 (ENE Gales Point, Belize)
 48H  03/1800Z 16.9N  89.4W   45 KT  50 MPH - Tropical Storm (ESE El Zapote, Guatemala)
 60H  04/0600Z 16.5N  91.7W   20 KT  25 MPH - Low (ESE La Independencia, Mexico)
 72H  04/1800Z...DISSIPATED

NWS National Hurricane Center Miami FL 100 PM EDT Tue Sep 01, 2020 

An Air Force Reserve reconnaissance aircraft investigating the vigorous disturbance south of Jamaica this morning has found that the system has a well-defined, closed circulation center. The aircraft also measured 60 kt at 925 mb in the northeastern quadrant and reliable SFMR surface winds of 45 kt. Based on these data, the system has been upgraded to Tropical Storm Nana, the 14th named tropical storm of the 2020 Atlantic hurricane season.

The initial motion estimate is an uncertain 280/14 kt, No significant changes were made to the previous track forecast. A strong deep-layer to the north of the system is expected to build slowly westward over the next few days, keeping the disturbance moving in a general west-northwestward to westward direction through 48 hours, followed by a turn toward the west-southwest shortly thereafter when the system will be inland over Central America. The NHC official forecast track lies close to a blend of the simple consensus models TVCN and GFEX, and the corrected-consensus model HCCA.

Nana has developed a well-defined upper-level anticyclone, with outflow gradually improving in all quadrants. Modest northeasterly to easterly vertical wind shear is expected to gradually subside to less than 10 kt by 48 hours, which should allow for at least some slow but steady strengthening, given that sea-surface temperatures (SST) will be 29.5-30.5 deg C along the track. Some dry air intrusions might hinder development for the next 24 hours or so, but the global and regional models still indicate that the atmosphere will moisten thereafter, and continue to moisten right up until landfall. Based on the higher initial intensity and the mostly favorable environmental conditions expected after 24 hours, the peak forecast intensity has been increased to 65 kt at 48 hours, just prior to landfall.

Due to the Nana’s expected proximity to Belize in 48 hours, a Tropical Storm Watch has been issued for that country. Additional watches and possible warnings will likely be required later today for Guatemala and the southern portion of the Yucatan Peninsula.

KEY MESSAGES:

  • 1. Tropical Storm Nana is now forecast to be a hurricane as it approaches the coast, and interests in Honduras, Guatemala, Belize and Yucatan should closely monitor the progress of this storm. Strong winds, dangerous storm surge and very heavy rainfall causing flash flooding are becoming more likely from Nana.
FORECAST POSITIONS AND MAX WINDS

INIT  01/1700Z 16.6N  77.9W   45 KT  50 MPH - Tropical Storm (WSW Kingston, Jamaica)
 12H  02/0000Z 16.6N  79.5W   50 KT  60 MPH - Tropical Storm (WSW Kingston, Jamaica)
 24H  02/1200Z 16.7N  82.3W   55 KT  65 MPH - Tropical Storm (WSW Kingston, Jamaica)
 36H  03/0000Z 16.8N  85.1W   60 KT  70 MPH - Tropical Storm (ENE Coxen Hole, Honduras)
 48H  03/1200Z 16.8N  87.4W   65 KT  75 MPH - Category 1 (ESE Hopkins, Belize)
 60H  04/0000Z 16.5N  89.6W   30 KT  35 MPH - Depression (ESE El Chal, Guatemala)
 72H  04/1200Z 15.7N  91.7W   15 KT  15 MPH - Low (ESE San Marcos Huist, Guatemala)
 96H  05/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 AM EDT Tue Sep 01 2020

An Air Force Reserve reconnaissance aircraft is currently investigating the vigorous tropical disturbance located south of Jamaica that the NHC has been tracking the past few days across the Caribbean Sea. An earlier report of 35 kt winds this morning from ship MAOR4 is the basis for the 35-kt initial intensity on Potential Tropical Cyclone Sixteen. (PTC-16)

The initial motion estimate is an uncertain 285/16 kt, based mainly on past scatterometer surface wind data and passive microwave satellite fix data. A strong deep-layer to the north of the system is expected to build slowly westward over the next few days, keeping the disturbance moving in a general west-northwestward to westward direction through 48 hours, followed by a turn toward the west-southwest shortly thereafter when the system will be inland over Central America. The NHC official forecast track lies close to a blend of the simple consensus models TVCN and GFEX, and the corrected-consensus model HCCA.

The disturbance has already developed an upper-level anticyclone, with outflow only restricted in the northeastern quadrant due to northeasterly shear of about 15 kt. This modest northeasterly to easterly vertical wind shear is expected to gradually subside to less than 10 kt by 48 hours, which should allow for at least some slow but steady strengthening, given that sea-surface temperatures (SST) will be 29.5-30.5 deg C along the track. Occasional intrusions of dry mid-level air might hinder development for the next 24-36 hours, but model guidance shows that the atmosphere is expected to moisten thereafter and right up until landfall. The official intensity forecast is similar to the consensus of the intensity guidance through 24 hours, and then is a little above the consensus at 36 h and 48 h due to the very warm waters, moistening atmosphere, and low shear conditions. The statistical SHIPS guidance suggests that the cyclone could reach hurricane strength just prior to landfall. This alternate scenario will be evaluated on the next advisory cycle.

Due to the system’s expected proximity to the north coast of Honduras and Roatan Island, a Tropical Storm Watch has been issued for those areas. Additional watches and possible warnings will likely be required later today for Guatemala, Belize, and the southern portion of the Yucatan Peninsula.

FORECAST POSITIONS AND MAX WINDS
 
INIT  01/1500Z 16.1N  77.5W   35 KT  40 MPH - Depression (WSW Kingston, Jamaica)
 12H  02/0000Z 16.4N  79.6W   35 KT  40 MPH - Tropical Storm (WSW Kingston, Jamaica)
 24H  02/1200Z 16.6N  82.3W   40 KT  45 MPH - Tropical Storm (WSW Kingston, Jamaica)
 36H  03/0000Z 16.7N  85.1W   45 KT  50 MPH - Tropical Storm (ENE Coxen Hole, Honduras)
 48H  03/1200Z 16.8N  87.4W   50 KT  60 MPH - Tropical Storm (ESE Hopkins, Belize)
 60H  04/0000Z 16.5N  89.6W   25 KT  30 MPH - Low (ESE El Chal, Guatemala)
 72H  04/1200Z 15.7N  91.7W   15 KT  15 MPH - Low (ESE San Marcos Huist, Guatemala)
 96H  05/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 200 PM EDT Mon Aug 31, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. A broad area of low pressure associated with a tropical wave over the central Caribbean Sea has changed little in organization since yesterday, and satellite-derived winds indicate that there is no closed circulation. However, environmental conditions are expected to gradually become more conducive for development, and a tropical depression is likely to form during the next couple of days while the system moves westward at 15 to 20 mph. Interests in Jamaica, Honduras, Belize, Guatemala and the Yucatan peninsula should monitor the progress of this disturbance. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…80 percent.
  • 2. An area of low pressure is located about 135 miles southeast of Wilmington, North Carolina. This system continues to become better organized, and a tropical depression is expected to form later today or tonight while the system moves northeastward, near but offshore of the southeastern coast of the United States and then away from land. An Air Force Reserve Hurricane Hunter aircraft is en route to investigate the system. * Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.
  • 3. A tropical wave is expected to emerge off the coast of Africa in a day or two. Gradual development of this system will be possible through the end of the week while it moves slowly westward over the far eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...30 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Mon Aug 31, 2020 

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. A broad area of low pressure associated with a tropical wave over the central Caribbean Sea has changed little in organization since yesterday. However, environmental conditions are expected to gradually become more conducive for development, and a tropical depression is likely to form during the next couple of days while the system moves westward at at 15 to 20 mph. Interests in Jamaica, Honduras, Belize, Guatemala and the Yucatan peninsula should monitor the progress of this disturbance. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…80 percent.
  • 2. An area of low pressure is located about 150 miles south-southeast of Wilmington, North Carolina. This system has become better organized overnight, and a tropical depression is likely to form within a day or so while the system moves northeastward, near but offshore of the southeastern coast of the United States, and then away from land. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate the system this afternoon if necessary. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…70 percent.
  • 3. A tropical wave is expected to emerge off the coast of Africa in a couple of days. Gradual development of this system will be possible through the end of the week while it moves slowly westward over the far eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.
  • 4. Another tropical wave is located over the eastern Atlantic Ocean, several hundred miles southwest of the Cabo Verde Islands. This system is producing little shower activity, and further development of this system is not expected. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…10 percent.

NWS National Hurricane Center Miami FL 200 AM EDT Mon Aug 31, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. Recent satellite imagery and satellite-derived wind data indicate that a broad area of low pressure associated with a tropical wave over the eastern Caribbean Sea has changed little in organization since yesterday. However, environmental conditions are expected to gradually become more conducive for development, and a tropical depression is likely to form during the next couple of days while the system moves moves westward at at 15 to 20 mph. Interests in Jamaica, Honduras, Belize, Guatemala and the Yucatan peninsula should monitor the progress of this disturbance. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…80 percent.
  • 2. An area of low pressure is located a few hundred miles east of Jacksonville, Florida. This system has gradually gotten better organized during the past 24 hours but is currently producing only limited showers and thunderstorms. Additional development is expected and a tropical depression is likely to form by the middle of the week while the system moves northeastward or east-northeastward, initially parallel to the southeastern coast of the U.S. and then away from land. Upper-level winds are expected to become less conducive for further development on Wednesday. * Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…70 percent.
  • 3. A tropical wave is expected to emerge off the coast of Africa in a couple of days. Gradual development of this system will be possible through the end of the week while it moves slowly westward over the far eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.
  • 4. Another tropical wave is located over the eastern Atlantic Ocean, several hundred miles southwest of the Cabo Verde Islands. This system is producing little shower activity, and any development of this system should be slow to occur as it moves slowly westward. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…10 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Sun Aug 30, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. Showers and thunderstorms continue to shows some signs of organization in association with a tropical wave and broad area of low pressure over the eastern Caribbean Sea. Environmental conditions are expected to gradually become more conducive for development, and a tropical depression is likely to form during the next day or two while the system moves moves westward at about 15 mph. Interests in Jamaica, Honduras, Belize, Guatemala and the Yucatan peninsula should monitor the progress of this disturbance. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…80 percent.

2. Satellite and radar images indicate that an area of low pressure is developing a couple of hundred miles east of Jacksonville, Florida. Environmental conditions appear conducive for some additional development, and a tropical depression is likely to form by the middle of the week while the system moves northeastward or east-northeastward, initially parallel to the southeastern coast of the U.S. and then away from land. * Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…70 percent.

3. A new tropical wave is expected to emerge off the coast of Africa in a couple of days. Gradual development of this system will be possible through the end of the week while it moves slowly westward over the far eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent. 4. A westward-moving tropical wave is located over the eastern Atlantic Ocean, several hundred miles southwest of the Cabo Verde Islands. This system is producing limited shower activity, and any development of this system should be slow to occur due to unfavorable environmental conditions. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Sun Aug 30, 2020 

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. A westward-moving tropical wave accompanied by a broad low pressure area is located over the eastern Caribbean Sea just west of the Windward Islands. Associated shower and thunderstorm activity continues to show signs of organization, and environmental conditions are expected to gradually become more conducive for development. A tropical depression is likely to form during the next day or two while the system moves moves westward at about 15 mph across the central Caribbean Sea. Interests in Jamaica, Honduras, Belize, Guatemala and Yucatan should monitor the progress of this disturbance. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high...80 percent.
  • 2. An area of low pressure is expected to form off the southeastern coast of the United States in a day or two. Subsequent development of this system is possible, and a tropical depression is likely to form by the middle of the week while the system moves northeastward or east-northeastward, initially parallel to the southeastern coast of the U.S. and then away from land. * Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…70 percent.
  • 3. A new tropical wave is expected to emerge off the coast of Africa in a couple of days. Gradual development of this system will be possible through the end of the week while it moves slowly westward over the far eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent. 4. A westward-moving tropical wave is located over the eastern Atlantic Ocean, several hundred miles southwest of the Cabo Verde Islands. This system is producing limited shower activity, and further development is becoming less likely due to unfavorable environmental conditions. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...20 percent.

NWS National Hurricane Center Miami FL 1210 PM EDT Sun Aug 30, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

Special Tropical Weather Outlook issued to update the discussion on the system over the eastern Caribbean Sea in the first paragraph.

  • 1. UPDATED: Showers and thunderstorms associated with a tropical wave over the eastern Caribbean Sea are beginning to show signs of organization. Recent satellite-derived surface winds also indicated that a broad low pressure system has formed in association with the wave. Additional development of this disturbance is expected over the next few days, and a tropical depression could form during the next couple of days while the system moves moves westward at about 15 mph across the Caribbean Sea. Interests in Jamaica, Honduras, Belize, Guatemala and Yucatan should monitor the progress of this disturbance. * Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…medium...60 percent.
  • 2. A westward-moving tropical wave is located over the eastern Atlantic Ocean, several hundred miles southwest of the Cabo Verde Islands. This system is producing limited shower activity, and any further development is expected to be slow to occur while it moves slowly westward over the eastern or central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.
  • 3. An area of low pressure is expected to form off the southeastern coast of the United States in a day or two. Subsequent development of this system is possible, and a tropical depression is likely to form by the middle of the week while the system moves northeastward or east-northeastward, initially parallel to the southeastern coast of the U.S. and then away from land. * Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…high…70 percent. 4. A new tropical wave is expected to emerge off the coast of Africa in a couple of days. Some gradual development of this system will be possible through the end of the week while it moves slowly westward over the far eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 per percent.

NWS National Hurricane Center Miami FL 800 PM EDT Sat Aug 29, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. A tropical wave located a few hundred miles east of the Windward Islands is producing disorganized showers and thunderstorms. Some gradual development of this system is possible during the next several days while it moves westward at 15 to 20 mph through the Lesser Antilles and the eastern and central Caribbean Sea. Regardless of development, this system will likely produce gusty winds and locally heavy rainfall across portions of the Windward and Leeward Islands on Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low...30 percent.
  • 2. Another tropical wave is located over the eastern Atlantic Ocean just southwest of the Cabo Verde Islands. This system is expected to move very slowly for the next several days, and some development is possible early next week over the eastern or central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent.
  • 3. A low-pressure area is expected to form off of the southeastern coast of the United States by early next week. Additional subsequent development is possible as the system moves east-northeastward across the northwestern Atlantic Ocean. * Formation chance through 48 hours…low…near 20 percent. * Formation chance through 5 days…low...30 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Sat Aug 29, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. A tropical wave located about 550 miles east of the Windward Islands is producing disorganized showers and thunderstorms. Some gradual development of this system is possible during the next several days while it moves westward at about 15 mph toward the Lesser Antilles. Regardless of development, this system will likely produce gusty winds and locally heavy rainfall across portions of the Windward and Leeward Islands on Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. Another tropical wave is located over the eastern Atlantic Ocean just southwest of the Cabo Verde Islands. This system is expected to move very slowly for the next several days, and some development is possible early next week over the eastern or central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium...40 percent.
  • 3. A low pressure area is expected to form off of the southeastern coast of the United States early next week. Additional subsequent development is possible as the system moves east-northeastward across the northwestern Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...20 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Sat Aug 29, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The Weather Prediction Center has issued its last advisory on Post-Tropical Cyclone Laura, located inland over northeastern Kentucky.

  • 1. A tropical wave located about 550 miles east of the Windward Islands is producing disorganized showers and thunderstorms. Some gradual development of this system is possible during the next several days while it moves westward at about 15 mph toward the Lesser Antilles. Regardless of development, this system will likely produce gusty winds and locally heavy rainfall across portions of the Windward and Leeward Islands on Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. Another tropical wave is located over the eastern Atlantic Ocean just southwest of the Cabo Verde Islands. This system is expected to move very slowly for the next several days, and some development is possible early next week over the eastern or central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Fri Aug 28, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The Weather Prediction Center is issuing advisories on Tropical Depression Laura, located inland over western Kentucky.

  • 1. A tropical wave located about 800 miles east of the Windward Islands is producing a disorganized area of showers and thunderstorms. Some gradual development of this system is possible during the next several days while it moves westward at about 15 mph toward the Lesser Antilles. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. Another tropical wave is located over the eastern Atlantic Ocean near the Cabo Verde Islands. This system is expected to move very slowly for the next several days, and some development is possible early next week over the eastern or central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Fri Aug 28 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The Weather Prediction Center is issuing advisories on Tropical Depression Laura, located inland over southeastern Missouri.

  • 1. A tropical wave located about 850 miles east of the Windward Islands is producing a disorganized area of showers and thunderstorms. Some gradual development of this system is possible during the next several days while it moves westward at about 15 mph toward the eastern Caribbean islands. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. Another tropical wave is located over the eastern Atlantic Ocean just west of the Cabo Verde Islands. The northern part of this wave, which should move rapidly westward over the central Atlantic during the next few days, is not forecast to develop as it is expected to remain in unfavorable environmental conditions. However, the southern part of the wave is expected to be nearly stationary south of the Cabo Verde Islands for the next several days, and some development of this system is possible early next week when it begins to move slowly westward over the eastern and central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Fri Aug 28 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The Weather Prediction Center is issuing advisories on Tropical Depression Laura, located inland over northeastern Arkansas.

  • 1. A tropical wave located about 900 miles east of the Windward Islands is producing an area of showers and thunderstorms. Some gradual development of this system is possible during the next several days while it moves westward at about 15 mph toward the eastern Caribbean islands. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. Another tropical wave is located over the eastern Atlantic Ocean just west of the Cabo Verde Islands. The northern part of this wave, which should move rapidly westward over the central Atlantic during the next few days, is not forecast to develop as it is expected to remain in unfavorable environmental conditions. However, the southern part of the wave is expected to be nearly stationary south of the Cabo Verde Islands for the next several days, and some development of this system is possible early next week when it begins to move slowly westward over the eastern and central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...30 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Thu Aug 27, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Storm Laura, located inland over southern Arkansas.

  • 1. Showers and thunderstorms associated with a tropical wave over the central tropical Atlantic have gradually become a little better organized during the day. Additional development of this system is possible during the next several days while it moves westward at about 15 mph. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. A tropical wave located over the eastern Atlantic Ocean just west of the Cabo Verde Islands is producing disorganized shower and thunderstorm activity. The northern part of this wave, which is expected to move rapidly westward over the central Atlantic during the next few days, is forecast to remain too far to the north and in an unfavorable environment for development to occur. However, the southern part of the wave is expected be nearly stationary south of the Cabo Verde Islands for the next several days, and some development of this system is possible early next week when it begins to move slowly westward over the eastern and central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Thu Aug 27 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Storm Laura, located inland over northwestern Louisiana.

  • 1. A westward-moving tropical wave located over the far eastern tropical Atlantic near the Cabo Verde Islands continues to produce disorganized shower activity. Although environmental conditions are not expected to be conducive for development during the next couple of days, they are forecast to gradually become more favorable over the weekend and into early next week when the wave moves into the central and then western tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.
  • 2. Shower and thunderstorm activity has increased today in association with a tropical wave over the central tropical Atlantic. Gradual development of this system is possible over the next several days as it moves westward at 15 to 20 mph. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…30 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Thu Aug 27, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on powerful Hurricane Laura, located inland over western Louisiana.

  • 1. A westward-moving tropical wave located over the far eastern tropical Atlantic, a couple of hundred miles east of the Cabo Verde Islands, continues to produce disorganized shower activity. Although environmental conditions are not expected to be conducive for development during the next couple of days, they are forecast to gradually become more favorable over the weekend and into early next week when the wave moves into the central tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...20 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Wed Aug 26, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on powerful Hurricane Laura, located just offshore the southwestern coast of Louisiana.

  • 1. A westward-moving tropical wave located just off the west coast of Africa about 400 miles east-southeast of the Cabo Verde Islands is producing disorganized shower activity. Although environmental conditions are not expected to be conducive for development during the next couple of days, they are forecast to gradually become more favorable over the weekend and into early next week when the wave moves into the central and western tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Wed Aug 26, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Hurricane Laura, located over the northwestern Gulf of Mexico.

  • 1. A westward moving tropical wave is expected to move off of the west coast of Africa tonight. Although environmental conditions do not appear to be conducive for development as the wave crosses the eastern Atlantic over the next few days, conditions could become more favorable for slow development of the system as it reaches the central and western tropical Atlantic early next week. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.

If this storm system is named, it will become Tropical Storm Nana.

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Video: Tropics Update: Tropical Depression Omar, Tropical Storm Nana and Three New Tropical Waves