Tropical Storm Gordon

Tropical Storm Gordon Rainfall 0800 Hours September 6 2018
Tropical Storm Gordon Rainfall 0800 Hours September 6 2018
Tropical Depression Gordon 2000 Hours September 6 2018
Tropical Depression Gordon 2000 Hours September 6 2018

Tropical Storm Gordon – NWS Weather Prediction Center College Park MD 1000 PM CDT Thu Sep 06 2018

DISCUSSION AND OUTLOOK  (see Thursday video below)

At 1000 PM CDT (0300 UTC), Tropical Depression Gordon was located near latitude 34.6 North, longitude 92.2 West. The depression was moving toward the northwest near 3 mph (6 km/h) and Gordon is expected to turn towards the north on Friday.

Maximum sustained winds are near 10 mph (20 km/h) with higher gusts. Little change in strength is forecast during the next 48 hours. The estimated minimum central pressure is 1013 mb (29.92 inches).

HAZARDS AFFECTING LAND

RAINFALL: Gordon is expected to produce total rain accumulations of 3 to 6 inches over northwest Mississippi and much of Arkansas, up into the Midwest, with possible isolated maximum amounts of 10 inches through Saturday night. This rainfall will likely cause local flooding and flash flooding.

FORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 34.6N  92.2W   10 KT  10 MPH - (Wrightsville, Arkansas)
 12H  07/1200Z 35.0N  92.4W   10 KT  10 MPH...INLAND - (Mayflower, Arkansas)
 24H  08/0000Z 35.9N  92.4W   10 KT  10 MPH...INLAND - (Timbo, Arkansas)
 36H  08/1200Z 37.3N  91.3W   15 KT  15 MPH...POST-TROP/EXTRATROP - (Midridge, Missouri)
 48H  09/0000Z 38.1N  89.9W   15 KT  15 MPH...POST-TROP/EXTRATROP - (Evansville, Illinois)
 72H  10/0000Z 40.3N  85.6W   20 KT  25 MPH...POST-TROP/EXTRATROP - (Summitville, Indiana  )
 96H  11/0000Z 44.4N  77.2W   25 KT  30 MPH...POST-TROP/EXTRATROP - (Greater Napanee, Ontario, Canada)
120H  12/0000Z 47.2N  65.8W   25 KT  30 MPH...DISSIPATED - (Trout Brook, New Brunswick, Canada)

NWS Weather Prediction Center College Park MD 400 AM CDT Thu Sep 06 2018

GORDON CONTINUES TO DRIFT THROUGH WESTERN MISSISSIPPI. THREAT OF HEAVY RAINS AND FLOODING WILL CONTINUE FOR SEVERAL DAYS.

DISCUSSION AND OUTLOOK

At 400 AM CDT (0900 UTC), Tropical Depression Gordon  was located near latitude 33.7 North, longitude 91.3 West. The depression is moving toward the west-northwest near 8 mph (13 km/h) and this motion is expected to continue today. Maximum sustained winds are near 25 mph (35 km/h) with higher gusts. Little change in strength is forecast during the next 48 hours. The estimated minimum central pressure is 1015 mb (29.98 inches).

HAZARDS AFFECTING LAND

RAINFALL: Gordon is expected to produce total rain accumulations of 3 to 7 inches over northwest Mississippi and much of Arkansas, up into the Midwest, with possible isolated maximum amounts of 10 inches through Saturday night. This rainfall will likely cause local flooding and flash flooding.

FORECAST POSITIONS AND MAX WINDS

INIT  06/0900Z 33.7N  91.3W   20 KT  25 MPH...INLAND - (ENE McArthur, Arkansas)
 12H  06/1800Z 33.9N  92.4W   20 KT  25 MPH...INLAND - (Ivan, Arkansas)
 24H  07/0600Z 34.0N  93.5W   20 KT  25 MPH...INLAND - (Delight, Arkansas)
 36H  07/1800Z 34.1N  93.8W   20 KT  25 MPH...INLAND - (Murfreesboro, Arkansas)
 48H  08/0600Z 34.9N  94.2W   20 KT  25 MPH...POST-TROP/REMNT LOW - (Winfield, Arkansas)
 72H  09/0600Z 38.1N  90.6W   20 KT  25 MPH...POST-TROP/EXTRATROP - (De Soto, Missouri)
 96H  10/0600Z 42.1N  84.6W   20 KT  25 MPH...POST-TROP/EXTRATROP - (Hanover, Michigan)

NWS National Hurricane Center Miami FL 1000 AM CDT Wed Sep 05 2018

Surface observations and WSR-88D Doppler radar data indicate that Gordon continues to weaken as it passes near Jackson, Mississippi, and the initial intensity has been reduced to a possibly generous 25 kt. Additional weakening is expected as the cyclone moves farther inland, and it is expected to decay to a remnant low pressure area in about 48 h. The remnant low is then expected to become extratropical as it merges with a frontal zone over the central United States by Saturday. Although Gordon has weakened, the threat of heavy rainfall and flooding will continue for the next few days.

The initial motion estimate is 320/12. Gordon should continue northwestward with a decrease in forward speed during the next 48 h as it moves along the southwestern side of a mid-level ridge. After that, the cyclone or its remnants are expected to turn northward and northeastward as it recurves into the westerlies. The new forecast track is similar to the previous one. However, during the first 48 h it lies to the east of the various consensus models due to a westward shift in the guidance since the last advisory. This will be the last advisory issued by the National Hurricane Center on Gordon.

Key Messages:

1. Even though Gordon is weakening, heavy rainfall will continue to affect the western Florida Panhandle, southwest Alabama, central Mississippi, Arkansas, Missouri, southern Iowa and Illinois, with isolated maximum amounts of 12 inches possible. This rainfall will cause flash flooding across portions of these areas.

FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 32.3N  90.2W   25 KT  30 MPH...INLAND - (WNW Jackson, Mississippi)
 12H  06/0000Z 33.3N  91.1W   25 KT  30 MPH...INLAND - (WSW Swiftwater, Mississippi)
 24H  06/1200Z 33.9N  92.2W   20 KT  25 MPH...INLAND - (WSW Toledo, Arkansas)
 36H  07/0000Z 34.5N  93.0W   20 KT  25 MPH...INLAND - WSW Hot Springs, Arkansas)
 48H  07/1200Z 35.3N  93.6W   20 KT  25 MPH...POST-TROP/REMNT LOW - ENE Subiaco, Arkansas)
 72H  08/1200Z 37.0N  93.5W   20 KT  25 MPH...POST-TROP/EXTRATROP - WSW Clever, Missouri)
 96H  09/1200Z 39.5N  90.0W   20 KT  25 MPH...POST-TROP/EXTRATROP - WNW Modesto, Illinois)
120H  10/1200Z 43.0N  84.0W   20 KT  25 MPH...POST-TROP/EXTRATROP - WNW Caledonia Township, Michigan)

NWS National Hurricane Center Miami FL 1000 PM CDT Tue Sep 04 2018

DISCUSSION AND OUTLOOK

At 1000 PM CDT (0300 UTC), the center of Tropical Storm Gordon  was located near latitude 30.3 North, longitude 88.4 West. Gordon is moving toward the northwest near 14 mph (22 km/h). A northwestward motion with some decrease in forward speed is expected over the next couple of days. On the forecast track, the center of Gordon will move inland across the lower Mississippi Valley through Wednesday. A turn toward the north-northwest and north is forecast to occur on Friday.

Maximum sustained winds are near 70 mph (110 km/h) with higher gusts. Rapid weakening is forecast after Gordon moves inland, and Gordon  is forecast to become a tropical depression on Wednesday.

Tropical-storm-force winds extend outward up to 80 miles (130 km) from the center. A NOAA Coastal Marine Observing site on Dauphin Island, Alabama has measured a sustained wind of 57 mph (91 km/h) with a gust to 72 mph (117 km/h). A wind gust of 61 mph (98 km/h) was recently observed at the Pensacola Naval Air Station.

The latest minimum central pressure estimated from NOAA Hurricane Hunter aircraft data is 997 mb (29.44 inches).

HAZARDS AFFECTING LAND

STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide… Mouth of the Mississippi River to Biloxi…1 to 3 ft. Biloxi to the Alabama/Florida Border including Mobile Bay…2 to 4 ft. Alabama/Florida Border to Navarre, Florida…1 to 3 ft. The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.

RAINFALL: Gordon is expected to produce total rain accumulations of 4 to 8 inches over the western Florida Panhandle, southwest Alabama, southern and central Mississippi, northeastern Louisiana, and southern Arkansas, with isolated maximum amounts of 12 inches through late Thursday. This rainfall will cause flash flooding across portions of these areas.

WIND: Tropical storm and hurricane conditions will continue to spread onshore during the next several hours within portions of the warning area.

TORNADOES: A couple of tornadoes are possible tonight near the coasts of Alabama and the western Florida Panhandle.

NWS National Hurricane Center Miami FL 1000 AM CDT Tue Sep 04 2018

After an earlier disruption of the inner-core convection due to some southerly wind shear, Gordon has since developed a band of deep convection very near the well-defined center noted in both NOAA GOES-16 high-resolution satellite imagery and coastal NOAA WSR-88D Doppler radars. In addition, there has been a significant increase in lightning activity during the past couple of hours in the inner core, and Doppler radar velocities have increased to more than 45 kt at 25,000 ft in the band of convection near the center. NOAA and Air Force Reserve reconnaissance aircraft further indicate that Gordon has maintained a small radius of maximum winds (RMW) of 10-15 nmi, and that SFMR surface winds of 53-55 kt exist in the northeastern quadrant. These data support an intensity of 55 kt.

The initial motion estimate is now toward the northwest at a slightly slower forward, or 305/13 kt. There is basically no change to the previous NHC forecast track reasoning. Reconnaissance fixes continue to fall along the previous forecast track, and the latest model guidance remains tightly packed and on top of the previous NHC forecast. As a result, there is high confidence that Gordon will make landfall along the north-central Gulf of Mexico coast in about 18 hours. After landfall, steering currents are forecast to weaken, resulting in Gordon slowing down considerably, which will enhance the heavy rainfall potential. By Friday, an approaching cold front and associated mid-/upper-level trough are expected to break down the subtropical ridge, allowing Gordon to turn northward and eventually turn northeastward on Saturday and merge with the cold front. The new official track forecast is near the model consensus and essentially on top of the previous NHC track.

The aforementioned inner-core changes that have been occurring could be a harbinger that Gordon is finally starting to intensify. Intense lightning activity inside the small RMW is an indication of strong updrafts, which can enhance the strengthening process. Although the GFS and ECMWF models continue to forecast northwesterly shear of 10-15 kt, the explicit upper-level wind fields in the GFS, ECMWF, and UKMET models indicate that the 200-mb flow is forecast to become southeasterly and diffluent across Gordon in the next 12 h or so, which would act to enhance the development of inner-core convection. As result, the official intensity forecast maintains continuity and shows Gordon becoming a hurricane before landfall, which is above the guidance through that time. Once Gordon moves inland, the small circulation should spin down fairly quickly, and that portion of the forecast closely follows the various consensus-model intensity guidance. By 120 h, Gordon’s circulation is expected to merge with a cold front over the Mississippi Valley region.

Key Messages:

1. Gordon is expected to bring life-threatening storm surge and hurricane conditions to portions of the central Gulf Coast where a Storm Surge Warning and Hurricane Warning are in effect. Residents in these areas should listen to advice from their local officials.

2. Heavy rainfall from Gordon will affect the western Florida Panhandle, southwest Alabama, southern and central Mississippi, much of eastern Louisiana, and southern Arkansas, where totals could reach as high as 12 inches. This rainfall will cause flash flooding in portions of these areas.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 28.5N  86.8W   55 KT  65 MPH - Tropical Storm (ESE Orange Beach, Alabama)
 12H  05/0000Z 29.8N  88.5W   65 KT  75 MPH - Category 1 (S Petit Bois Island, Mississippi)
 24H  05/1200Z 31.5N  90.2W   35 KT  40 MPH...INLAND
 36H  06/0000Z 32.8N  91.6W   25 KT  30 MPH...INLAND
 48H  06/1200Z 33.7N  92.7W   20 KT  25 MPH...INLAND
 72H  07/1200Z 35.4N  94.3W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  08/1200Z 37.7N  93.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  09/1200Z 40.9N  90.7W   20 KT  25 MPH...POST-TROP/EXTRATROP

NWS National Hurricane Center Miami FL 1100 PM EDT Mon Sep 03 2018

WSR-88D radar data from Tampa shows that the small inner core of Gordon has lost some organization during the past few hours, and GOES-16 satellite imagery and recent aircraft fixes indicate that the low-level center is located near the southwestern edge of the main convective mass. This suggests that there may be some light to moderate westerly shear affecting the cyclone. The Air Force Reserve reconnaissance aircraft recently measured peak 850-mb flight-level winds of 57 kt, and SFMR winds of 50-55 kt. A blend of these data yields an initial wind speed estimate of 50 kt. A UW/CIMSS shear analysis and the SHIPS model indicates that there is about 10-15 kt of westerly shear over the system. The SHIPS guidance shows a slight relaxation of the shear during the next 12-18 hours while the system moves over the warm waters of the Gulf of Mexico, which should allow for some strengthening. However, Gordon is a small tropical cyclone and subtle changes in shear (both up and down) can result in fairly quick intensity changes for systems like this. The NHC intensity forecast assumes that shear will not be prohibitive and that Gordon will become a hurricane before reaching the northern Gulf coast. The NHC intensity forecast is close to the SHIPS guidance through 24 hours, then follows the HFIP corrected consensus after landfall which shows Gordon weakening rapidly over land.

Gordon is moving west-northwestward at about 15 kt. The tropical storm is expected to maintain a west-northwestward to northwestward heading during the next few days while it moves around the southwestern portion of a large deep-layer ridge centered over the Mid-Atlantic states. After that time, the cyclone should decelerate as it moves around the western periphery of the ridge. The track guidance continues to be tightly clustered through 72 h, and no significant changes were required to the previous NHC track forecast.

Key Messages:

1. Gordon is expected to bring life-threatening storm surge and hurricane conditions to portions of the central Gulf Coast where a Storm Surge Warning and Hurricane Warning are in effect. Residents in these areas should listen to advice from their local officials. All preparations to protect life and property should be rushed to completion, as tropical storm conditions are expected to arrive in the warning areas Tuesday afternoon.

2. Heavy rainfall from Gordon will affect southern Alabama, southern Mississippi and Louisiana, where totals could reach as high as 8 inches. This rainfall could cause flash flooding.

FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 26.9N  84.3W   50 KT  60 MPH - Tropical Storm (SW Venice, Florida)
 12H  04/1200Z 28.3N  86.3W   55 KT  65 MPH - Tropical Storm (S Miramar Beach, Florida)
 24H  05/0000Z 30.0N  88.6W   65 KT  75 MPH - Category 1 (S Horn Island, Mississippi)
 36H  05/1200Z 31.6N  90.3W   40 KT  45 MPH...INLAND
 48H  06/0000Z 32.9N  91.6W   25 KT  30 MPH...INLAND
 72H  07/0000Z 34.6N  93.9W   20 KT  25 MPH...INLAND
 96H  08/0000Z 36.5N  94.9W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  09/0000Z 39.5N  93.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

NWS National Hurricane Center Miami FL 500 PM EDT Mon Sep 03 2018

At 500 PM EDT (2100 UTC), the center of Tropical Storm Gordon was located by NOAA Doppler weather radars near latitude 26.2 North, longitude 82.6 West. Gordon is moving toward the west-northwest near 17 mph (28 km/h) and a west-northwestward to northwestward motion is expected over the next 72 hours. On the forecast track, the center of Gordon will move farther away from the southwestern coast of Florida early this evening, and move across the eastern Gulf of Mexico tonight and Tuesday. The center of Gordon will approach the central Gulf Coast within the warning area late Tuesday or Tuesday night, and move inland over the lower Mississippi Valley on Wednesday.

Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Gradual strengthening is forecast during the next 36 hours, and Gordon is expected to be a hurricane when it makes landfall along the central Gulf Coast.

Tropical-storm-force winds extend outward up to 45 miles (75 km) from the center.

The estimated minimum central pressure is 1006 mb (29.71 inches) based on earlier reports from an Air Force Reserve reconnaissance aircraft.

HAZARDS AFFECTING LAND

Shell Beach Mississippi
Shell Beach Mississippi

STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide… Shell Beach to Dauphin Island, Alabama…3 to 5 ft. Navarre Florida to Dauphin Island, including Mobile Bay…2 to 4 ft.

Shell Beach to the Mouth of Mississippi River…2 to 4 ft. Mouth of the Mississippi River to the Louisiana-Texas border…1 to 2 ft.

The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.

RAINFALL: Gordon is expected to produce total rain accumulations of 2 to 4 inches over the northwestern Bahamas, Florida Keys, and South Florida through early Tuesday. Isolated maximum amounts of 8 inches are possible over the southern Florida peninsula. Gordon is expected to produce total rain accumulations of 4 to 6 inches over southern Alabama, southern and central Mississippi, and southeastern and northeastern Louisiana, with isolated maximum amounts of 8 inches through late Thursday. These rainfall amounts may cause flash flooding.

WIND: Tropical storm conditions will continue for the next few hours in the warning area across southwestern Florida. Tropical storm conditions are expected within portions of the central Gulf Coast warning area by late Tuesday, with hurricane conditions expected late Tuesday or Tuesday night in the hurricane warning area.

TORNADOES: A couple of tornadoes are possible through tonight across the southern and west-central Florida Peninsula.

NWS National Hurricane Center Miami FL 200 PM EDT Mon Sep 03 2018

At 200 PM EDT (1800 UTC), the center of Tropical Storm Gordon was located near latitude 25.8 North, longitude 81.9 West. Gordon is moving toward the west-northwest near 16 mph (26 km/h) and a west- northwestward to northwestward motion is expected over the next 72 hours. On the forecast track, the center of Gordon will move farther away from the southwestern coast of Florida this afternoon and move across the eastern Gulf of Mexico tonight and Tuesday. The center of Gordon will approach the coast within the warning area along the central Gulf Coast by late Tuesday or Tuesday night, and move inland over the lower Mississippi Valley on Wednesday.Tropical Storm Gordon Wind Speeds 1100 Hours September 3 2018

Maximum sustained winds have increased to near 50 mph (85 km/h) with higher gusts. Additional strengthening is forecast during the next 36 hours, and Gordon is expected to be near hurricane strength when it makes landfall along the central Gulf Coast.

Tropical-storm-force winds extend outward up to 45 miles (75 km) from the center. The estimated minimum central pressure is 1007 mb (29.74 inches).

HAZARDS AFFECTING LAND

STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide… Shell Beach to the Mississippi-Alabama border…3 to 5 ft. Navarre Florida to the Mississippi-Alabama border…2 to 4 ft. Shell Beach to the Mouth of Mississippi River…2 to 4 ft. Mouth of the Mississippi River to the Louisiana-Texas border…1 to 2 ft. The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.

RAINFALL: Gordon is expected to produce total rain accumulations of 2 to 4 inches over the central and northwestern Bahamas, the Florida Keys, and South Florida through early Tuesday. Isolated maximum amounts of 8 inches are possible over the southern Florida peninsula. Gordon is expected to produce total rain accumulations of 4 to 6 inches over southern Alabama, southern Mississippi and Louisiana, with isolated maximum amounts of 8 inches through early Thursday. These rainfall amounts may cause flash flooding.

WIND: Tropical storm conditions will continue through this afternoon in the warning areas across South Florida and the Florida Keys. Tropical storm conditions are expected within portions of the central Gulf Coast warning area by late Tuesday, with hurricane conditions possible late Tuesday or Tuesday night in the hurricane watch area.

TORNADOES: A couple of tornadoes are possible through tonight across the southern and west-central Florida Peninsula.

NWS National Hurricane Center Miami FL 1100 AM EDT Mon Sep 03 2018

Surface observations from the Florida Keys and southeast Florida, along with Doppler velocity data from the Miami radar, indicate that Gordon   has continued to become organized this morning. The center of the cyclone passed over Key Largo between 1100-1200 UTC, producing a west wind in Islamorada and also at an observing site in Florida Bay. Doppler velocity data and surface observations support an intensity of 40 kt for this advisory. An Air Force Reserve Unit reconnaissance aircraft is currently investigating Gordon.

The initial motion estimate is 300/14 kt. The latest model guidance has shifted slightly to the right, but this is likely due to the more northerly initial position. Other than that, the models remain tightly packed and agree on a general west-northwestward to northwestward motion for the next 48 hours right up until landfall as the strong ridge to the north of Gordon moves little. The new NHC forecast track was adjusted a little to the right of the previous advisory track, but not as far to the east as some of the model guidance out of respect for the reliable ECMWF deterministic run, which is located on the southern edge of the guidance and shows landfall near the mouth of the Mississippi River, a solution that is also supported by the new 0600Z short-range UKMET model run.

Gordon’s appearance in both radar and satellite imagery has continued to improve over the past several hours. The GFS- and ECMWF-based SHIPS models indicate that westerly to northwesterly vertical wind shear of about 10 kt is allegedly affecting Gordon, but there are no indications of that in satellite imagery that I can see. The cirrus outflow has continued to expand in all quadrants, so the analyzed westerly shear is likely an artifact of the small circulation being positioned so close to the strong trough located its west. Since Gordon will be moving over sea-surface temperatures near 30 deg C during the next 36-48 hours, and be near or underneath an upper-level anticyclone, steady strengthening seems likely. It is possible that Gordon could peak as a Category 1 hurricane after 36 hours, just before landfall occurs. For that reason, a Hurricane Watch has been issued for portions of the central Gulf Coast. The new intensity forecast is above the previous advisory, and is close to a blend of the consensus models HCCA, FSSE, and IVCN.

Key Messages:

1. Gordon will bring heavy rainfall and tropical storm conditions to portions of South Florida and the Florida Keys today and a Tropical Storm Warning remains in effect for these areas.

2. Gordon is expected to bring life-threatening storm surge to portions of the central Gulf Coast and a Storm Surge Warning has been issued from the Mouth of the Pearl River to the Mississippi- Alabama border. Residents in these areas should listen to advice from their local officials and all preparations to protect life and property should be rushed to completion.

3. A Tropical Storm Warning and Hurricane Watch are in effect for portions of the central Gulf Coast. Tropical storm conditions are expected to reach those areas late Tuesday, with hurricane conditions possible in the watch area.

4. Heavy rainfall from Gordon will affect southern Alabama, southern Mississippi and Louisiana, where totals could reach as high as 8 inches. This rainfall could cause flash flooding.

FORECAST POSITIONS AND MAX WINDS

INIT  03/1500Z 25.3N  81.3W   40 KT  45 MPH - Tropical Storm (S Everglades City, Florida)
 12H  04/0000Z 26.5N  83.4W   45 KT  50 MPH - Tropical Storm (E Cape Coral, Florida)
 24H  04/1200Z 28.1N  86.0W   50 KT  60 MPH - Tropical Storm (S Destin, Florida)
 36H  05/0000Z 29.9N  88.4W   60 KT  70 MPH - Tropical Storm (S Pascagoula, Missisippi)
 48H  05/1200Z 31.3N  90.3W   40 KT  45 MPH...INLAND
 72H  06/1200Z 33.9N  93.2W   25 KT  30 MPH...INLAND
 96H  07/1200Z 34.8N  94.9W   20 KT  25 MPH...INLAND
120H  08/1200Z 37.6N  95.1W   20 KT  25 MPH...POST-TROP/REMNT LOW

NWS National Hurricane Center Miami FL 830 AM EDT Mon Sep 03 2018

Tropical Storm Gordon- Surface observations from the Florida Keys and southeast Florida, along with Doppler velocity data from the Miami radar, indicate that the disturbance has developed a closed surface circulation and a well-defined center. Recent observations from a Weatherflow site at Carys Fort Reef and radar data support increasing the maximum winds to at least 40 kt. As a result of these data, the system has been upgraded to Tropical Storm Gordon, the seventh named system of the 2018 Atlantic hurricane season. An Air Force Reserve Unit reconnaissance aircraft is enroute to investigate Gordon.

The initial motion estimate is 300/15 kt and the previous forecast track remains unchanged. The intensity forecast was adjusted upward in the first 24 to 36 hours to account for the initial increase in intensity. Some additional adjustments may be required after the reconnaissance aircraft completes its mission and provides more detailed information on the stricture and intensity of Gordon.

Key Messages:

1. Gordon will bring heavy rainfall and tropical storm conditions to portions of South Florida and the Florida Keys today and a Tropical Storm Warning is in effect for these areas.

2. A Tropical Storm Warning is in effect for portions of the central Gulf Coast, and tropical storm conditions are expected in those areas beginning late Tuesday. Heavy rainfall from Gordon will affect portions of the central Gulf Coast over the next few days, including areas that have already received heavy rainfall from a different weather system. Interests in these areas should monitor products from their local National Weather Service office.

FORECAST POSITIONS AND MAX WINDS

INIT  03/1230Z 25.1N  80.7W   40 KT  45 MPH - Tropical Storm (Samphire Keys, Florida)
 12H  03/1800Z 25.7N  82.1W   45 KT  50 MPH - Tropical Storm (WSW Marco Island,Florida)
 24H  04/0600Z 27.2N  84.8W   50 KT  60 MPH - Tropical Storm (SWS Sarasota, Florida)
 36H  04/1800Z 28.8N  87.4W   50 KT  60 MPH - Tropical Storm (S Gulf Shores, Alabama)
 48H  05/0600Z 30.4N  89.7W   50 KT  60 MPH - Tropical Storm (NE Pearl River, Louisiana)
 72H  06/0600Z 33.0N  92.7W   30 KT  35 MPH...INLAND
 96H  07/0600Z 34.0N  95.0W   25 KT  30 MPH...INLAND
120H  08/0600Z 35.5N  96.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

NWS National Hurricane Center Miami FL 500 PM EDT Sun Sep 02 2018

The area of disturbed weather associated with a tropical wave that the NHC has been tracking for the past few days has become better organized today. Strong winds previously associated with an upper- level trough just west of the system have decreased significantly during the day, and the upper-level flow across the disturbance has become more anticyclonic. Earlier scatterometer wind data indicated that the system does not yet have a closed surface circulation. However, the same data indicate that winds of 25-28 kt exist outside of thunderstorm activity, with some higher gusts likely present. The initial intensity is being set at a conservative 25 kt for this advisory.

The initial motion estimate is an uncertain 300/13 kt. The global models are in excellent agreement that the strong subtropical ridge to the north of the disturbance will remain entrenched across the southeastern U.S. and mid-Atlantic states throughout the forecast period. This flow pattern should keep the system moving in a west- northwestward to northwestward motion until landfall occurs along the central Gulf coast in 60-72 hours. The model tracks are tightly packed, so the NHC official forecast track essentially lies down the middle of the guidance envelope. On the forecast track, the system is expected to move across the Florida Keys Monday afternoon, and reach the central Gulf Coast by Tuesday night or Wednesday morning.

The aforementioned upper-level anticyclonic has been steadily increasing during the day today, with weak cirrus outflow now occurring in all quadrants. The disturbance is forecast to move across the very warm waters of the Gulfstream late tonight and early Monday morning where local diabatic heating should enhance deep convection near the mid-level circulation, causing the vortex column to build downward to the surface. Once a closed surface circulation develops, the combination of low to modest vertical shear and SSTs of at least 30C along the track should allow for at least slow but steady strengthening. Although the official intensity forecast shows weakening at 72 hours, this is due to the system expected to be inland at that time. Conditions will favorable for continued strengthening after the 48-h period until landfall occurs, and a peak intensity of around 55 kt around 60 hours is possible. The SHIPS and LGEM models were the only intensity guidance available for this package, and the official forecast is just a little below an average of those models. The HWRF and HMON models will be forthcoming for the next advisory package, so some adjustments to this first intensity forecast may be required as more guidance becomes available.

Key Messages:

1. Potential Tropical Cyclone Seven will bring heavy rainfall and gusty winds to portions of the Bahamas, South Florida, and the Florida Keys tonight and Monday, and interests in those areas should monitor the progress of this system.

2. A Tropical Storm Watch has been issued for portions of the central Gulf Coast, and tropical storm conditions are possible in those areas Tuesday night and Wednesday. Heavy rainfall from this system will affect portions of the central Gulf Coast later this week, including areas that are currently receiving heavy rainfall from a different weather system. Interests in these areas should monitor products from their local National Weather Service office.

3. Users should be aware that forecast uncertainty for potential tropical cylones is generally larger than that for tropical cyclones, especially beyond 48-72 hours.

FORECAST POSITIONS AND MAX WINDS

INIT  02/2100Z 22.7N  77.3W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
 12H  03/0600Z 23.7N  79.3W   30 KT  35 MPH...TROPICAL DEPRESSION
 24H  03/1800Z 25.1N  81.9W   35 KT  40 MPH...Tropical Storm
 36H  04/0600Z 26.6N  84.5W   40 KT  45 MPH...Tropical Storm
 48H  04/1800Z 28.0N  87.1W   50 KT  60 MPH...Tropical Storm
 72H  05/1800Z 30.6N  91.6W   35 KT  40 MPH...INLAND
 96H  06/1800Z 33.0N  94.0W   25 KT  30 MPH...INLAND
120H  07/1800Z 34.0N  95.5W   20 KT  25 MPH...POST-TROP/REMNT LOW

NWS National Hurricane Center Miami FL 800 AM EDT Sun Sep 2 2018

For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Tropical Storm Florence, located several hundred miles west of the Cabo Verde Islands.

1. Disorganized showers and thunderstorms over the southeastern and central Bahamas and adjacent Atlantic waters, including the Straits of Florida, are associated with a tropical wave interacting with an upper-level trough. This weather system is expected to move west-northwestward across the remainder of the Bahamas, southern Florida, and the Florida Keys during the next day or so and little, if any, development is expected during that time due to strong upper-level winds. However, the current unfavorable upper-level wind pattern is expected to gradually change and become more conducive for a tropical depression to form over the eastern and central Gulf of Mexico by Tuesday or Wednesday. This disturbance will spread locally heavy rains across much of the Bahamas, southern Florida, and the Keys during the next day or two. See products from your local weather forecast office for more information. * Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…high…80 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Sat Sep 1 2018 

For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Tropical Storm Florence, located about a couple of hundred miles west of the Cabo Verde Islands.

Cloudiness and showers over the Turks and Caicos Islands and the southeastern Bahamas have increased a little bit today. This activity is associated with a tropical wave interacting with an upper-level trough. This weather system is expected to spread westward across the remainder of the Bahamas this weekend, and move across southern Florida and into the eastern Gulf of Mexico by early next week. Surface pressures are not falling at this time, and development is not anticipated during the next day or two. Environmental conditions, however, are forecast to become a little more favorable for a surface low pressure area to form when the disturbance moves across the Gulf of Mexico during the early to middle part of next week. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Sat Sep 1 2018

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

The National Hurricane Center is issuing advisories on recently upgraded Tropical Storm Florence, located about a couple of hundred miles west of the Cabo Verde Islands.

1. A tropical wave interacting with an upper-level trough is producing numerous showers and thunderstorms from Hispaniola northward across the Turks and Caicos Islands. This activity is forecast to spread west-northwestward, enhancing rainfall across Hispaniola, the Turks and Caicos Islands, the Bahamas this weekend, and across Florida and the northern Gulf of Mexico coast by early next week. Strong upper-level winds will likely prevent significant development of this system during the next couple of days, but environmental conditions are expected to become a little more favorable for a surface low pressure area to form when the disturbance moves across the Gulf of Mexico during the early to middle part of next week. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Fri Aug 31 2018

For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Tropical Depression Six, located just south-southwest of the Cabo Verde Islands.

Disorganized showers and thunderstorms extending from Hispaniola northward for a few hundred miles over the adjacent Atlantic waters are associated with a tropical wave interacting with an upper-level trough. This activity is forecast to spread westward or west-northwestward enhancing the rainfall across portions of Hispaniola, the Turks and Caicos Islands, the Bahamas, and Florida into early next week. Strong upper-level winds are expected to prevent any development of this system during the next 2 to 3 days, but environmental conditions could become less hostile when the system reaches the eastern Gulf of Mexico during the early to middle part of next week. * 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 Fri Aug 31 2018

For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Potential Tropical Cyclone Six, passing south of the Cabo Verde Islands. * Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.

Disorganized cloudiness and showers extending from Hispaniola northeastward to the adjacent Atlantic are associated with a tropical wave interacting with an upper-level trough. This activity is forecast to spread westward to west-northwestward enhancing the rainfall across portions of Hispaniola, the Bahamas, the Turks and Caicos Islands, and Florida into early next week. Strong upper-level winds will prevent any development of this system during the next 2 to 3 days, but environmental conditions could become less hostile when the system reaches the eastern Gulf of Mexico during the early to middle part of next week. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...10 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Fri Aug 31 2018

For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Potential Tropical Cyclone Six, located a couple of hundred miles east- southeast of the Cabo Verde Islands. * Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.

1. Disorganized cloudiness and showers from Hispaniola eastward to the Leeward Islands and the adjacent waters are associated with a tropical wave interacting with an upper-level trough. This activity is forecast to spread westward to west-northwestward enhancing the rainfall across portions of Hispaniola, the Bahamas, the Turks and Caicos Islands, and Florida into early next week. Strong upper-level winds will prevent any development of this system during the next 2 to 3 days, but environmental conditions could become less hostile when the system reaches the eastern Gulf of Mexico during the early to middle part of next week. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…10 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Thu Aug 30 2018

For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Potential Tropical Cyclone Six, located southeast of the Cabo Verde Islands.

1. A tropical wave located over the north-central Caribbean Sea is producing a large area of cloudiness and thunderstorms extending from Hispaniola northeastward across the northeastern Caribbean Sea and adjacent Atlantic waters. This activity is forecast to spread westward to west-northwestward, but strong upper-level winds are expected to prevent any significant development of this system during the next several days. Environmental conditions could become more conducive when the system reaches the eastern Gulf of Mexico early next week. Regardless of development, this system could produce enhanced rainfall across portions of Hispaniola, the Bahamas, the Turks and Caicos, and Florida into early next week. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…10 percent.

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