[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN DEC 15 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
GALE WARNING FOR THE GULF OF MEXICO S OF 22N W OF 94W ASSOCIATED
WITH A COLD FRONT EXTENDING FROM 26N82W TO 19N92W AT 15/2100
UTC. THE WARNING IS VALID UNTIL 16/0000 UTC WHEN WINDS ARE
EXPECTED TO SUBSIDE. SEE THE HIGH SEAS FORECAST...
MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE FORECAST...
MIAOFFNT4/FZNT24 KNHC...FOR MORE DETAILS.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE TROPICAL
EASTERN ATLC NEAR 08N13W AND CONTINUES TO 06N15W. THE ITCZ AXIS
EXTENDS FROM 06N15W AND CONTINUES ALONG 03N29W TO 02N40W TO
0N50W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE
FROM 02N-11N E OF 27W AND FROM 02N-06N BETWEEN 28W-41W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING ALONG THE
EASTERN CONUS INTO THE CENTRAL GULF CONTINUE TO SUPPORT A COLD
FRONT THAT AT 15/2100 UTC EXTENDS FROM 25N81W SW TO 23N85W TO
19N91W OVER THE EASTERN BAY OF CAMPECHE. LOW-LEVEL MOISTURE
CONVERGENCE ALONG THE FRONTAL BOUNDARY SUPPORTS RAINSHOWERS AND
TSTMS WITHIN 120 NM S OF IT. A PRE-FRONTAL TROUGH EXTENDS FROM
21N86W...ALONG THE EASTERN YUCATAN PENINSULA TO CENTRAL
GUATEMALA NEAR 15N90W TO ENHANCE SHOWERS IN THE YUCATAN CHANNEL.
A HIGH PRESSURE SYSTEM ANCHORED BY THREE HIGH PRESSURE
CENTERS...ONE IN THE LOWER MISSISSIPPI VALLEY...ANOTHER OVER THE
SOUTHERN PLAINS AND A THIRD OVER NE MEXICO EXTENDS A RIDGE
ACROSS THE GULF. THIS HIGH PRESSURE SYSTEM IS PUSHING AN ARCTIC
AIRMASS INTO THE NORTHERN AND CENTRAL GULF WHICH CONTINUE TO
SUPPORT FAIR WEATHER BASIN WIDE BEHIND THE COLD FRONT. A TIGHT
PRESSURE GRADIENT FROM THIS RIDGE OVER THE SW GULF SUPPORTS GALE
FORCE WINDS. SEE THE SPECIAL FEATURES FOR MORE DETAILS ABOUT THE
GALE WARNING. HIGH PRESSURE WILL CONTINUE ACROSS THE GULF
THROUGHOUT WED AFTERNOON. THE PORTION OF THE COLD FRONT IN THE
SE GULF IS EXPECTED TO STALL WITHIN THE NEXT 24 HOURS WHILE IT
SLOWLY DISSIPATES.

CARIBBEAN SEA...
LOW-LEVEL MOISTURE CONVERGENCE ASSOCIATED WITH A SURFACE PRE-
FRONTAL TROUGH FROM 21N86W...ALONG THE EASTERN YUCATAN PENINSULA
TO CENTRAL GUATEMALA NEAR 15N90W ENHANCES RAINSHOWERS IN THE
YUCATAN CHANNEL THAT EXTENDS TO THE NW CARIBBEAN W OF 83W. LOW-
LEVEL MOISTURE CONVERGENCE IS ALSO ALONG THE COAST OF EASTERN
HONDURAS TO THE COAST OF SOUTHERN NICARAGUA WHICH ALONG WITH
UPPER-LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION AND
TSTMS FROM 11N-17N W OF 80W. IN THE SW BASIN...THE MONSOON
TROUGH AXIS EXTENDS ACROSS COSTA RICA TO NORTHERN COLOMBIA AND
SUPPORT ISOLATED SHOWERS AND TSTMS S OF 11N W OF 78W. WATER
VAPOR IMAGERY DEPICT STRONG SUBSIDENCE FROM THE MIDDLE LEVELS
ACROSS THE REMAINDER BASIN WHICH SUPPORTS FAIR WEATHER
CONDITIONS. A RELATIVELY STRONG PRESSURE GRADIENT ACROSS THE
CENTRAL AND EASTERN BASIN SUPPORTS EASTERLY WINDS IN THE RANGE
OF 20-25 KT. A COLD FRONT CURRENTLY OVER THE SE GULF IS FORECAST
TO TRANSITION INTO A STATIONARY FRONT OVER THE NW CARIBBEAN
WITHIN THE NEXT 24 HOURS.

HISPANIOLA...
FAIR WEATHER CONTINUES OVER HISPANIOLA SUPPORTED BY DRY AIR AT
THE LOWER AND MIDDLE LEVELS. WEATHER CONDITIONS ARE FORECAST TO
DEGRADE BY MONDAY MORNING WHEN A VERY MOIST AIRMASS IS EXPECTED
TO MOVE ACROSS THE ISLAND ENHANCING SHOWERS.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING ALONG THE
EASTERN CONUS INTO THE CENTRAL GULF SUPPORTS A COLD FRONT
ANALYZED IN THE SW N ATLC FROM 30N74W SW TO SOUTHERN FLORIDA
NEAR 26N79W. SCATTERED MODERATE CONVECTION AND TSTMS ARE WITHIN
110 NM SE OF FRONT. SURFACE HIGH PRESSURE RIDGING IS OVER THE
REMAINDER ATLC N OF 15N THAT ALONG WITH DRY AIR AT THE LOW AND
MIDDLE LEVELS CONTINUE TO SUPPORT FAIR WEATHER.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NR


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