Tropical Weather Discussion

- as issued by NHC/TPC -

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Tropical Weather Discussion (NHC/TPC):
NWS National Hurricane Center Miami FL
646 AM EST Thu Dec 13 2018

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 0600 UTC surface analysis and satellite imagery through 
1130 UTC. 


...Gulf of Mexico Gale Warning...

A cold front is forecast to enter the northwest Gulf of Mexico by
early this afternoon. The front will shift across the Gulf waters,
moving E of the Gulf Saturday. Gale force winds are expected 
tonight through Fri morning behind the front over the northwest 
and west-central Gulf waters, with winds diminishing later Fri. 
Please read the latest High Seas Forecast under AWIPS/WMO headers 
HSFAT2/FZNT02 KNHC for more details.


The monsoon trough extends from the coast of Sierra Leone near
07N12W to 03N21W. The ITCZ continues from that point to 02N25W to
01N37W to the coast of Brazil near 02S44W. Scattered moderate 
convection is seen from 01N-04W between 40W-52W. Between the W 
coast of Africa and 40W, isolated to scattered showers are noted
within a few degrees of the monsoon trough and ITCZ.


A surface high pressure ridge continues to retreat away from the
eastern Gulf as a 1025 mb surface high is now over the western
Atlantic off the SE U.S coast. A 999 mb surface low over the Texas
Panhandle has an associated cold front extending into southern 
New Mexico. In advance of the front, scattered thunderstorms are 
currently occurring over the NW Gulf W of 93.5W and N of 24.5N, 
including over the Houston and Beaumont Texas areas. These storms 
are being enhanced by upper-level diffluence over the western 
Gulf. Light showers are occurring over the northern Gulf offshore 
of Alabama and Mississippi and well as the W Florida Panhandle to 
the SE tip of Louisiana.

The cold front that is currently over NW Texas and SE New Mexico 
will quickly sweep across Texas this morning, reaching the NW Gulf
of Mexico this afternoon. The front will shift E across the Gulf 
waters, moving E of the area Sat. Strong to near gale force 
northerly flow west of the front will increase to gale force 
tonight over the northwest and west-central Gulf waters before 
diminishing Fri afternoon. Near gale force southerly flow is 
expected east of the front tonight into Fri. Seas of 10-16 ft 
will cover a large portion of the western and central Gulf by 
Friday behind the front. In addition, strong thunderstorms are
expected ahead of and along with the front beginning today, 
especially over the northern half of the Gulf, as the front sweeps
across the Gulf from west to east. Locally enhanced winds and seas
can be expected near the stronger thunderstorms. High pres will 
build in the wake of the front this weekend and prevail through 
early next week. 

A surface trough is present in the NW Caribbean from 21N83W to
16.5N85.5W. Isolated showers are near the trough. Most of the
Caribbean is relatively quiet with no significant convection and 
only some light showers.

Fresh to strong trade winds will prevail across the central 
Caribbean, with nocturnal pulses to near gale force off the 
northwest coast of Colombia. A cold front will move into the NW 
Caribbean Fri, where it will dissipate this weekend. Northerly 
swell will reach the Leewards on Sat, and spread south through the
northeast Caribbean passages this weekend.


A cold front extends from 32N50W to 28N55W to 24N65W, then 
continues as a stationary front from that point to the Windward 
Passage. Scattered showers are noted along and ahead of the front 
north of 30N. To the east, a surface trough is analyzed along 41W
from 17N-24N with isolated showers. A 1028 mb surface high is 
centered near 31N28W and extends a ridge across most of the 
remainder of the basin east of the front.

The front from 23N65W to the Windward Passage will begin to drift
N today. Southerly return flow will develop later today into 
Friday ahead of the next cold front forecast to move into the NW 
waters on Fri night. The front will shift eastward this weekend, 
reaching a position from Bermuda to central Cuba on Sun night. 

For additional information please visit

Graphical representation of waves, etc. on this image (NCEP/OPC) [more].
Various tropical satellite imagery available here

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