[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131153
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 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 03N28W TO 03N42W. ISOLATED SHOWERS ARE WITHIN 70 NM
BETWEEN 22W-37W.

...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 24N80W SW TO THE
NE YUCATAN PENINSULA NEAR 21N87W. RADAR AND SATELLITE IMAGERY
CONTINUE TO SHOW ISOLATED SHOWERS OVER THIS REGION OF THE SE
GULF. A 1032 MB HIGH CENTERED OVER SE TENNESSEE NEAR 35N85W
EXTENDS A RIDGE INTO THE GULF AND PROVIDES NORTHEASTERLY WIND
FLOW UP TO 20 KT ACROSS THE BASIN. SSMI TPW IMAGERY DEPICT AN
ARCTIC AIRMASS 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 27N 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 100 NM FROM THE COAST. OVER THE
CENTRAL BASIN...A MIDDLE-LEVEL LOW CENTERED NEAR 11N76W SUPPORTS
A SURFACE TROUGH FROM EASTERN CUBA NEAR 20N74W TO NORTHERN
COLOMBIA NEAR 10N75W. ISOLATED SHOWERS ASSOCIATED WITH THE
TROUGH ARE N OF 17N BETWEEN 72W-77W...INCLUDING THE WINDWARD
PASSAGE AND JAMAICA. MIDDLE-LEVEL DIFFLUENCE GENERATED BY THE
LOW S OF THE CENTRAL CARIBBEAN AND THE SW PERIPHERY OF A BROAD
ANTICYCLONIC CIRCULATION OVER THE CENTRAL ATLC SUPPORTS ISOLATED
SHOWERS AND TSTMS N OF 13N BETWEEN 65W-69W. 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...
A MIDDLE-LEVEL LOW CENTERED NEAR 11N76W SUPPORTS A SURFACE
TROUGH FROM EASTERN CUBA NEAR 20N74W TO NORTHERN COLOMBIA NEAR
10N75W. ISOLATED SHOWERS ASSOCIATED WITH THE TROUGH ARE N OF 17N
BETWEEN 72W-77W...INCLUDING THE WINDWARD PASSAGE AND HAITI.
WHILE THE TROUGH CONTINUES TO MOVE WESTWARD THIS MORNING A DRY
AIRMASS MOVES ACROSS THE ISLAND TO SUPPORT FAIR WEATHER
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 30N61W SW TO 27N68W TO 25N73W WHERE IT
TRANSITIONS TO A STATIONARY FRONT TO THE FLORIDA STRAITS. VERY
DRY AIR ACROSS THE SW NORTH ATLC AND CENTRAL ATLC HINDERS
CONVECTION AT THE TIME. FARTHER EAST OVER THE CENTRAL ATLC...A
1027 MB HIGH IS NEAR 29N37W 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 WEST OF
THE CANARY ISLANDS ALONG 31N20W TO 22N20W WITH NO CONVECTION
ASSOCIATED WITH IT AT THE TIME. OTHERWISE...AN AREA OF SCATTERED
SHOWERS IS LOCATED FROM 11N-18N E OF 34W...INCLUDING THE CAPE
VERDE ISLANDS.

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

$$
NR

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