[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI DEC 13 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE EAST
TROPICAL ATLC NEAR 09N13W TO 07N17W. THE ITCZ AXIS EXTENDS FROM
07N17W TO 03N30W TO 0N46W. ISOLATED SHOWERS ARE WITHIN 100 NM
EITHER SIDE OF THE AXES.

...DISCUSSION...

GULF OF MEXICO...
A BROAD MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING ALONG
THE NORTHWESTERN ATLC SUPPORTS A FRONTAL SYSTEM ANALYZED AS A
STATIONARY FRONT FROM THE FLORIDA STRAITS NEAR 23N81W TO THE
YUCATAN CHANNEL NEAR 21N86W...REGION OF THE SE GULF WHERE RADAR
IMAGERY SHOW ISOLATED SHOWERS. A 1033 MB HIGH CENTERED OVER
WESTERN TENNESSEE NEAR 35N88W EXTENDS A RIDGE INTO THE GULF AND
PROVIDES NORTHEASTERLY WIND FLOW UP TO 25 KT ACROSS THE BASIN.
SSMI TPW IMAGERY DEPICT AN ARCTIC AIR MASS PUSHING INTO THE NE
GULF AND ALSO VERY DRY AIR ACROSS THE REMAINDER BASIN WHICH IS
SUPPORTING FAIR WEATHER. IN THE UPPER-LEVEL...SOUTHWESTERLY WIND
FLOW ADVECTS MOISTURE FROM THE EPAC ITCZ REGION TO SUPPORT
BROKEN TO OVERCAST SKIES ACROSS THE NORTHERN GULF N OF 26N W OF
87W. HIGH PRESSURE AND NORTHEASTERLY WIND FLOW ARE EXPECTED TO
CONTINUE ACROSS THE GULF THROUGHOUT FRI MORNING. RETURN FLOW
STARTS TO BUILD ACROSS THE GULF FRI AFTERNOON AS THE HIGH
PRESSURE CENTER MOVES TO NW ATLC WATERS NEAR THE COAST OF NORTH
CAROLINA. THE PORTION OF THE FRONTAL BOUNDARY ACROSS THE SE GULF
IS FORECAST TO DISSIPATE EARLY FRI. A NEW COLD FRONT IS
FORECAST TO EMERGE ACROSS THE NW GULF SAT AFTERNOON.

CARIBBEAN SEA...
LOW-LEVEL MOISTURE CONVERGENCE IS ALONG THE COASTLINE FROM THE
YUCATAN PENINSULA TO CENTRAL PANAMA TO SUPPORT SCATTERED
MODERATE CONVECTION WITHIN 120 NM FROM THE COAST. OVER THE
CENTRAL BASIN...A MIDDLE-LEVEL INVERTED TROUGH SUPPORTS A
SURFACE TROUGH FROM THE WINDWARD PASSAGE NEAR 20N73W TO NORTHERN
COLOMBIA NEAR 11N73W. ISOLATED SHOWERS ASSOCIATED WITH THE
TROUGH ARE N OF 14N BETWEEN 71W-77W. ANOTHER SURFACE TROUGH
APPEARS TO BE S OF PUERTO RICO WHICH IS GENERATING SHOWERS S OF
17N BETWEEN 61W-68W. ACROSS THE REMAINDER BASIN DRY AIR
SUBSIDENCE FROM THE MIDDLE LEVELS DOMINATE TO SUPPORT FAIR
WEATHER. OTHERWISE...A RELATIVELY TIGHT PRESSURE GRADIENT OVER
THE CENTRAL-EASTERN BASIN SUPPORTS 20-25 KT WINDS EXPECTED TO
PERSIST THROUGHOUT SAT MORNING.

HISPANIOLA...
AN INVERTED TROUGH AT THE MIDDLE-LEVEL OVER THE CENTRAL
CARIBBEAN SUPPORTS A SURFACE TROUGH EXTENDING ACROSS THE
WINDWARD PASSAGE NEAR 20N73W TO NORTHERN COLOMBIA NEAR 11N73W.
ISOLATED SHOWERS ASSOCIATED WITH THE TROUGH ARE N OF 14N BETWEEN
71W-77W. ISOLATED SHOWERS COULD BE EXTENDING TO HAITI AS THE
TROUGH SLOWLY DRIFTS WESTWARD TONIGHT. OTHERWISE...FAIR WEATHER
IS FORECAST THROUGHOUT SAT AFTERNOON.

ATLANTIC OCEAN...
A BROAD MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING ALONG
THE NORTHWESTERN ATLC SUPPORTS A FRONTAL SYSTEM ANALYZED AS A
COLD FRONT FROM 30N64W SW TO 25N73W TO 23N81W. VERY DRY AIR
ACROSS THE SW NORTH ATLC AND CENTRAL ATLC HINDERS CONVECTION AT
THE TIME. FARTHER EAST OVER THE CENTRAL ATLC...A 1028 MB HIGH IS
NEAR 29N40W WHICH IS EXPECTED TO DRIFT NE OVER THE NEXT 24 HOURS
MAINTAINING FAIR WEATHER CONDITIONS ACROSS MOST OF THE ATLC. A
WEAK SURFACE TROUGH IS FARTHER EAST ACROSS THE CANARY ISLANDS
FROM 33N17W SE TO INLAND AFRICA NEAR 23N15W WITH NO CONVECTION
ASSOCIATED WITH IT AT THE TIME. OTHERWISE...AN AREA OF SCATTERED
SHOWERS IS LOCATED FROM 12N-18N E OF 37W...INCLUDING THE CAPE
VERDE ISLANDS.

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

$$
NR


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