Tropical Storm Cosme

Tropical Depression Cosme Track 0200 Hours July 8 2019
Tropical Depression Cosme Track 0200 Hours July 8 2019

 

Tropical Storm Cosme Forming Satellite 1400 Hours July 7 2019Tropical Storm Cosme – NWS National Hurricane Center Miami FL 200 AM PDT Mon Jul 08, 2019

Cosme continues to gradually weaken over 23 to 24 degree C waters and in a dry and stable atmospheric environment with about 10 to 15 kt of westerly shear. The depression now consists of scattered mid- to high- level debris clouds over a low-level swirl, with a small area of convection located nearly 200 n mi northeast the system’s center. A scatterometer pass at 0450 UTC showed peak winds of 25 kt associated with Cosme’s circulation. This intensity agrees with the satellite intensity estimates from TAFB and ADT and will be the depression’s initial intensity for this advisory.

The unfavorable environmental conditions for Cosme will not improve as the depression continues to move over cooler waters today. This should prevent any significant amounts of deep convection from developing near the system’s center, and Cosme is expected to become a remnant low at some point later on today.

The initial motion of Cosme is northwest at 8 kt. This general motion will continue through today with a slowing in forward speed. Thereafter, the remnant low will drift northwestward to west-northwestward in the low-level flow until it dissipates.

FORECAST POSITIONS AND MAX WINDS

INIT  08/0900Z 19.8N 120.1W   25 KT  30 MPH - Tropical Storm (WSW Clarion Island, Mx)
 12H  08/1800Z 20.4N 120.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  09/0600Z 21.0N 121.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  09/1800Z 21.5N 122.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  10/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 200 PM PDT Sun Jul 07, 2019

Deep convection has been pulsing since the previous advisory, with a small burst of thunderstorms have recently developed in the northwestern quadrant. Satellite data indicate that the low-level center is less than 45 nmi from the -30 deg C cloud tops and cirrus has been blowing off toward the southeast across the center, indications that convective feedback is still maintaining Cosme as a tropical cyclone. The initial intensity remains 35 kt for this advisory based on a few 30-33 kt vectors that were present in an 1813Z ASCAT-B partial scatterometer pass over the northwestern quadrant of Cosme’s surface wind field.

The initial motion estimate is 315/09 kt. Cosme is expected to move northwestward tonight and then turn toward the west-northwest by Monday afternoon, maintaining that motion throughout the remainder of the forecast period as the shallow circulation comes under the influence of the low-level easterly trade wind flow. The new NHC track forecast is a little north of the previous advisory track and is similar to a blend of the HCCA, TVCE, and TVDG consensus models.

Cosme has just passed over the 26-deg-C SST isotherm and water temperatures ahead of the cyclone are forecast to cool to near 24C in about 24 hours. The combination of cooler waters, entrainment of dry stable air, and increasing northwesterly wind shear is expected to bring about the demise of Cosme in 12-24 hours. The cyclone is expected to weaken to a tropical depression later tonight, becoming a post-tropical system on Monday, and dissipating by 96 hours, if not sooner. The new official intensity forecast is similar to the previous advisory, and closely follows the HCCA, FSSE, and IVCN intensity consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 18.6N 119.0W   35 KT  40 MPH - Tropical Storm (WSW Clarion Island, Mx)
 12H  08/0600Z 19.2N 119.9W   30 KT  35 MPH - Tropical Storm (WSW Clarion Island, Mx)
 24H  08/1800Z 19.9N 120.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  09/0600Z 20.4N 121.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  09/1800Z 20.9N 122.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  10/1800Z 21.7N 124.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  11/1800Z...DISSIPATED

NWS National Hurricane Center Miami FL 800 AM PDT Sun Jul 07, 2019

After a brief convective hiatus overnight, a small burst of thunderstorms have redeveloped near and to the northeast of the low-level center this morning, making positioning of the tropical cyclone a little difficult. However, convection has been on the wane during the past couple of hours despite relatively low vertical wind shear conditions. The initial intensity has been maintained at 35 kt due to the increase in central convection.

The initial position and motion estimate of 305/08 kt is based primarily on passive microwave satellite data. Cosme is forecast to maintain a northwestward to west-northwestward motion over the next few days due to the influence of a deep-layer ridge located to the north of the cyclone. A 72-hr post-tropical position was added due to the global models now hanging on to a closed surface low a little bit longer. Otherwise, the new NHC forecast track is similar to but north of the previous advisory track, mainly due to the more northward initial position, and lies close to a blend of the HCCA and the simple consensus models.

Cosme is moving over marginal 26-deg-C SSTs, and the water beneath the cyclone is forecast to cool to near 25C in about 24 hours. The unfavorable oceanic conditions, combined with the entrainment of drier and more stable low- and mid-level air, should result in complete loss of deep convection near the center by Monday. As a result, Cosme is forecast to become a depression later today, degenerate into a post-tropical remnant low on Monday, and dissipate in the 72-96 hour time period. The new official intensity forecast is similar to the previous advisory and closely follows the HCCA and IVCN intensity consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 17.7N 118.4W   35 KT  40 MPH - Tropical Storm (WSW Clarion Island, Mx)
 12H  08/0000Z 18.4N 119.5W   30 KT  35 MPH - Tropical Storm (WSW Clarion Island, Mx)
 24H  08/1200Z 19.1N 120.4W   30 KT  35 MPH - Tropical Storm (WSW Clarion Island, Mx)
 36H  09/0000Z 19.7N 121.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  09/1200Z 20.2N 122.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  10/1200Z 21.2N 124.2W   20

NWS National Hurricane Center Miami FL 200 PM PDT Sat Jul 06, 2019

Tropical Storm Cosme (see video below) continues to have a lopsided appearance in satellite images, with all of its associated deep convection east of the center. While there have been some cells near the core of the cyclone, they have not lasted long due to plentiful dry air in the mid-levels. The initial wind speed is kept at 45 kt in agreement with recent ASCAT data, again well above any Dvorak estimates.

While shear is clearly decreasing near the center, it will take some time for the large cyclone to mix out the aforementioned dry near and west of the core. In addition, Cosme has only about 36 hours over marginal SSTs before reaching cool waters. These factors indicate little significant strengthening this weekend, and a gradual weakening early next week due to cooler waters and higher shear. The HWRF shows some strengthening right before Cosme crosses into the cool waters, but the rest of the models holds Cosme’s intensity flat or decreasing during the next few days. The official intensity forecast is similar to the previous one, which goes with the weaker solution provided by the bulk of the models.

The center has been difficult to track, but ASCAT and visible satellite suggest it is moving a bit slower and poleward than before, or 295/12. The storm is expected to be steered to the west- northwest during the next day or so due to a subtropical ridge over Mexico. However, all of the models show a break in the ridge forming between 120-130W, which should induce a motion more to the northwest by Monday. Guidance has shifted a bit to the north on this cycle, and the ECMWF solution remains a bit of an outlier to the southwest. The new NHC forecast is adjusted slightly to the northeast of the previous one but is southwest of the model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  06/2100Z 16.2N 116.3W   45 KT  50 MPH - Tropical Storm (WSW Clarion Island, Mx)
 12H  07/0600Z 16.9N 117.8W   45 KT  50 MPH - Tropical Storm (WSW Clarion Island, Mx)
 24H  07/1800Z 17.8N 119.2W   45 KT  50 MPH - Tropical Storm (WSW Clarion Island, Mx)
 36H  08/0600Z 18.8N 120.3W   40 KT  45 MPH - Tropical Storm (WSW Clarion Island, Mx)
 48H  08/1800Z 19.8N 121.1W   35 KT  40 MPH - Tropical Storm (WSW Clarion Island, Mx)
 72H  09/1800Z 21.0N 122.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  10/1800Z 21.5N 125.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  11/1800Z...DISSIPATED

NWS National Hurricane Center Miami FL 800 AM PDT Sat Jul 06, 2019

Tropical Storm Cosme – The broad area of low pressure that we have been monitoring for several days has finally consolidated into a tropical storm. Satellite images show that a well-defined center is present on the western side of an area of deep convection which has been getting closer to the center. The initial wind speed is set to 45 kt in agreement with the overnight scatterometer data, which is higher than what Dvorak-only estimates would suggest.

Shear near Cosme has been decreasing during the overnight hours, with cirrus cloud motions suggesting that easterly flow is overspreading the circulation. However, it will take some time for the large cyclone to overcome the very dry mid-level air near and west of the core. In addition, Cosme has only about 36 hours over lukewarm SSTs before reaching cool waters. These factors suggest little significant strengthening this weekend, and a gradual weakening early next week due to sub-26C waters and higher shear. Only the HWRF shows any significant increase in wind speed, with the rest of the models holding Cosme’s intensity flat or decreasing during the next few days. The official intensity forecast goes with the latter solution, not too far from the model consensus.

An uncertain estimate of initial motion is 290/12. Cosme should be steered to the west-northwest for the next day or so due to a subtropical ridge over Mexico. However, all of the models show a break in the ridge forming between 120-130W, which will likely induce a motion more to the northwest by Monday. There isn’t a lot of agreement, however, on exactly when that turns occurs, with the GFS-based guidance and UKMET turning the system earlier than the ECMWF and most of its ensemble. I don’t have a lot of reason to favor either solution at this time, so the forecast will stay close to the eastern Pacific track model consensus TVCE. Based on SSTs and model-simulated satellite data, Cosme should become a non-convective remnant low in about 3 days.

FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 15.6N 115.7W   45 KT  50 MPH - Tropical Storm (WSW Clarion Island, Mx)
 12H  07/0000Z 16.3N 117.4W   45 KT  50 MPH - Tropical Storm (WSW Clarion Island, Mx)
 24H  07/1200Z 17.0N 119.1W   45 KT  50 MPH - Tropical Storm (WSW Clarion Island, Mx)
 36H  08/0000Z 17.9N 120.3W   45 KT  50 MPH - Tropical Storm (WSW Clarion Island, Mx)
 48H  08/1200Z 18.8N 121.2W   40 KT  45 MPH - Tropical Storm (WSW Clarion Island, Mx)
 72H  09/1200Z 20.2N 122.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  10/1200Z 21.0N 125.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  11/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 PM PDT Fri Jul 5, 2019

For the eastern North Pacific…east of 140 degrees west longitude: The National Hurricane Center is issuing advisories on Tropical Storm Barbara, located a little more than 1700 miles west of the southern tip of the Baja California Peninsula.

A broad area of low pressure located several hundred miles south-southwest of the southern tip of the Baja California Peninsula is producing tropical-storm-force winds. While the associated thunderstorm activity remains disorganized, recent satellite wind data indicates the circulation of the low is becoming better defined. If current trends continue, a tropical storm could form later today or tonight while the system moves west-northwestward at about 15 mph.

* Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 1105 AM PDT Fri Jul 5, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical Storm Barbara, located nearly 1550 miles west of the southern tip of the Baja California Peninsula.

1. Updated: Recent satellite data right after the Tropical Weather Outlook was released indicate that the broad area of low pressure several hundred miles south of the southwestern coast of Mexico is already producing tropical storm force winds, but still lacks a well-defined center. Environmental conditions are becoming more conducive for development, and a tropical depression or a tropical storm is expected to form this weekend as the system moves west-northwestward at about 15 mph, remaining well off the coast of Mexico.

* Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Fri Jul 5, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara, located nearly 1500 miles west of the southern tip of the Baja California Peninsula

A broad area of low pressure is located several hundred miles south of the southwestern coast of Mexico. Satellite images indicate that the shower activity has not become any better organized since yesterday. However, environmental conditions are still conducive for development and a tropical depression is likely to form this weekend as the system moves west-northwestward at about 15 mph, remaining well off the coast of Mexico.

* Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 500 PM PDT Thu Jul 4, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara, located nearly 1500 miles west-southwest of the southern tip of the Baja California Peninsula.

A large area of disturbed weather associated with a tropical wave is located several hundred miles south of the southwestern coast of Mexico. This system is showing signs of organization and a broad surface low has developed. Environmental conditions appear conducive for further development and a tropical depression is likely to form this weekend. The low is expected to move west-northwestward at about 15 mph, remaining well off the coast of Mexico.

* Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Thu Jul 4, 2019

For the eastern North Pacific…east of 140 degrees west longitude: The National Hurricane Center is issuing advisories on Hurricane Barbara, located in the far southwestern portion of the eastern Pacific.

Showers and thunderstorms continue to show some signs of organization in association with a tropical wave located several hundred miles south-southwest of the coast of southwestern Mexico. Environmental conditions appear conducive for further development, and a tropical depression is likely to form this weekend. This disturbance is expected to move west-northwestward at about 15 mph well off the coast of Mexico.

* Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…high…80 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Thu Jul 4, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara, located in the far southwestern portion of the eastern Pacific.

Showers and thunderstorms are showing some signs of organization in association with a tropical wave located several hundred miles south of the coast of southwestern Mexico. Environmental conditions appear conducive for further development, and a tropical depression is likely to form this weekend. This disturbance is expected to move west-northwestward at about 15 mph well off the coast of Mexico for the next several days.

* Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…high…80 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Wed Jul 3, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara, located about 1250 miles west-southwest of the southern tip of the Baja California peninsula. A large area of disturbed weather located several hundred miles south of the southern coast of Mexico is associated with a tropical wave.

Although this system is showing some signs of organization on satellite imagery, it lacks a surface circulation at this time. Environmental conditions, however, are conducive for gradual development of this system and a tropical depression is likely to form over the weekend while this system moves westward to west-northwestward at about 15 mph well south of the coast of Mexico.

* Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high...80 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Wed Jul 3, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara located a little more than 1200 miles west-southwest of the southern tip of the Baja California peninsula.

A large but disorganized area of showers and thunderstorms located several hundred miles south of the southern coast of Mexico is associated with a tropical wave. Environmental conditions appear conducive for the gradual development of this system, and a tropical depression is likely to form over the weekend while this system moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high...80 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Wed Jul 3, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara located a little more than 1200 miles west-southwest of the southern tip of the Baja California peninsula.

A large but disorganized area of showers and thunderstorms located several hundred miles south of the southern coast of Mexico is associated with a tropical wave. Environmental conditions appear conducive for the gradual development of this system, and a tropical depression is likely to form over the weekend while this system moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high…80 percent.

NWS National Hurricane Center Miami FL 500 PM PDT Tue Jul 2, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara, located more than 1100 miles southwest of the southern tip of the Baja California peninsula.

An area of low pressure is forecast to develop later this week several hundred miles southwest of the southern coast of Mexico. Environmental conditions are expected to be favorable for this system to become a tropical depression over the weekend while it moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…high…70 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Tue Jul 2, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara, located more than 1000 miles southwest of the southern tip of the Baja California peninsula. An area of low pressure is forecast to develop later this week several hundred miles southwest of the southern coast of Mexico.

Environmental conditions are expected to be favorable for this system to become a tropical depression over the weekend while it moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…high…70 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Tue Jul 2, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane Barbara, located more than 1000 miles southwest of the southern tip of the Baja California peninsula.

An area of low pressure is forecast to develop later this week several hundred miles southwest of the southern coast of Mexico. Environmental conditions are expected to be favorable for this system to become a tropical depression over the weekend while it moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…high…70 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Mon Jul 1, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical Storm Barbara located several hundred miles south-southwest of the southern tip of the Baja California peninsula. An area of low pressure is expected to form late this week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for a gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days… medium…60 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Mon Jul 1, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical Storm Barbara, located several hundred miles south-southwest of the southern tip of the Baja California peninsula.

An area of low pressure is expected to form later this week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for the gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…60 percent.

NWS National Hurricane Center Miami FL 1100 PM PDT Sun Jun 30, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical Storm Barbara, located several hundred miles south-southwest of the southern tip of the Baja California peninsula.

An area of low pressure is expected to form by the middle of next week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for the gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…60 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Sun Jun 30, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on recently developed Tropical Storm Barbara, located several hundred miles south of the southern tip of the Baja California peninsula.

An area of low pressure is expected to form by the middle of next week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for the gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days … medium …50 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Sun Jun 30, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

An area of low pressure is expected to form by the middle of next week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for the gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent.

 

NWS National Hurricane Center Miami FL 500 PM PDT Sat Jun 29, 2019

An area of low pressure is expected to form by the middle of next week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...30 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Sat Jun 29, 2019

For the eastern North Pacific…east of 140 degrees west longitude:

An area of low pressure is expected to form by the middle of next week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for the gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Sat Jun 29, 2019

Corrected to make Alvin a depression For the eastern North Pacific…east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on recently downgraded Tropical Depression Alvin, located several hundred miles west of the southern tip of the Baja California peninsula.

An area of low pressure is expected to form by the middle of next week several hundred miles south of the southern coast of Mexico. Conditions appear favorable for a gradual development of this system while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.

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Video: Soon Tropical Storm Cosme – THE WEATHER CHANNEL LIVE – July 5, 2019