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000
AXNT20 KNHC 221752
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1252 PM EST Wed Nov 22 2017

Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through 1630 UTC.


...SPECIAL FEATURES... A 1012 mb low is centered near 25N89W with a cold front surging southward to the west of the low. As of 1500 UTC, a pre-frontal trough extends from the low to near Vera Cruz, Mexico. The low and cold front will merge later today as the low moves NE. Frequent gusts to gale force have been occurring this morning over the NW Gulf to the NW of the cold front. Sustained gale force winds will occur over the SW Gulf with the passage of the pre- front trough, and re- enforced by the cold front. The gusts over the NW Gulf will diminish below gale force late this evening. The sustained gale over the SW Gulf will end Friday morning. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/ FZNT02 KNHC for more details.

A new area of low pressure of 1013 has developed near 28N71W. gale force winds are forecast to develop this evening over the SE semicircle of the low. This gale will persist over this portion of the low through tonight as the low moves NE and north of 31N. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/ FZNT02 KNHC for more details.


...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 09N13W to 06N20W. The Intertropical Convergence Zone extends from 06N20W to 06N35W to 08N48W. A surface trough is just east of where the ITCZ terminates and extends from 11N50W to 06N52W. Scattered moderate convection is from 06N to 11N between 40W and 60W, and from 03N to 11N between 11W and 35W.


...DISCUSSION...

GULF OF MEXICO... A complex system is dominating the Gulf basin today. A stationary front extends across central Florida to a weakening 1013 mb low near 28N85W. The stationary front continues to another low of 1012 mb near 25N89W. As of the 1500 UTC analysis, a pre-frontal trough extended from the low to the SW Gulf near Vera Cruz, while a cold front lagged just behind the lows over the north central Gulf from 31N85W to 26N94W, then surges southward over the western Gulf to near Tampico, Mexico. This location of the front was confirmed by both surface observation dewpoints and scatterometer wind data. Scattered moderate convection with numerous embedded thunderstorms is occurring within 300 nm SE of the cold front. Frequent gusts to gale force are occurring over the NW gulf NW of the front, and sustained gale force winds are developing behind the pre-frontal trough over the SW Gulf. Please refer to the special features section for more details. Fresh to strong NE winds are elsewhere NW of the cold front. Mainly gentle to moderate winds are SE of the pre-frontal trough and lows. Over the next 24 hours the cold front will merge with the central Gulf low. The central Gulf low will move NE and absorb the NE gulf low. Thunderstorms will continue SE of the cold front.

CARIBBEAN SEA... A surface trough extends from 21N80W to 11N80W. This trough is interacting with moist SW flow in the mid to upper levels to support a cluster of moderate convection from 16N to 22N between 77W and 80W, and a broad area of shower activity S of 16N W of the trough axis. Mainly gentle to moderate winds are over the western Caribbean W of 78W. Moderate to locally fresh E to SE winds are over the Caribbean E of 78W. Over the next 24 hours showers and thunderstorms will continue near the surface trough.


...HISPANIOLA... Clear skies and relatively tranquil conditions are noted across the island today. Scattered thunderstorms may begin to affect the south portion of the island later today as an upper trough to the west digs SE toward the region.

ATLANTIC OCEAN... A weakening cold front extends from 31N75W to 28N79W, where it transitions to a dissipating stationary front over central Florida. No convection is noted with this front. A new area of low pressure of 1013 mb as of 1500 UTC was centered near 27N71W. A developing warm front extends from 25N66W to the low. A developing cold front extends from the low to near 24N76W. A pre-frontal trough extends from the low to near 22N75W. A cluster of moderate convection is within 210 nm E of the low. Widely scattered thunderstorms are within 210 NM SE of the developing cold front. Strong southerly winds are between the pre- frontal trough and warm front N of 25N. Fresh to strong SE winds extend from the warm front NE to beyond the 31N border of our area of discussion, W of 60W. The winds over the SE semicircle of the low are expected increase to near gale or gale force later this evening as the low moves NE and deepens. Please refer to the special features section for more details on this gale. Farther east, a cold front enters the area of discussion near 31N43W and extends to 28N55W where it transitions to a stationary front to 39N62W, then transitions to a warm front to beyond 31N67W. No deep convection is noted with this front at this time. A weakening frontal system covers the E Atlantic waters. A cold front enters the area of discussion near 31N17W to 23N26W where it transitions to a stationary front to a 1012 mb low near 21N42W. A surface trough extends from this low to near 17N53W. No deep convection is associated with this system. Over the next 24 hours the new low over the western Atlantic will exit the area of discussion with a trailing front over the SW N Atlantic waters. The cold front over the central Atlantic will continue eastward. The frontal system over the E Atlantic will dissipate, while the associated low drifts SW.

For additional information please visit http://www.hurricanes.gov/marine

$$ Latto

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