[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081144
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN DEC 08 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.

...SPECIAL FEATURE...

ATLANTIC BASIN...A GALE WARNING IS IN EFFECT UNTIL 09/0000 UTC
FOR THE CENTRAL ATLC N OF 27N BETWEEN 42W AND 48W ASSOCIATED
WITH A COLD FRONT EXTENDING FROM 23N35W TO 17N46W. PLEASE SEE
THE HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02
KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE TROPICAL
ATLC NEAR 04N08W TO 05N13W. THE ITCZ BEGINS NEAR 05N13W AND
CONTINUES TO 07N25W TO 07N41W THEN IT RESUMES WEST OF A SURFACE
TROUGH NEAR 06N46W TO THE COAST OF SOUTH AMERICA NEAR 04N51W.
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 02N-
11N BETWEEN 25W-42W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE...MIDDLE AND UPPER LEVEL RIDGING CONTINUES TO DOMINATE
THE GULF WATERS THIS MORNING. HOWEVER...THERE IS A WEAKNESS IN
THE SURFACE RIDGE WHERE A STATIONARY FRONT IS ANALYZED FROM NW
FLORIDA NEAR 29N83W SW TO 27N90W TO THE BAY OF CAMPECHE NEAR
18N92W. NORTHWESTERLY WIND FLOW AROUND THE WESTERN PERIPHERY OF
THE MIDDLE TO UPPER LEVEL RIDGE IS ADVECTING SOME MOISTURE TO
THE SOUTHERN AND NORTH-CENTRAL GULF TO SUPPORT SCATTERED
RAINSHOWERS WITHIN 60 NM W OF THE FRONT BETWEEN 88W-91W AS WELL
AS S OF 21N E OF 93W. DRY AIR SUBSIDENCE FROM THE MIDDLE LEVELS
AS WELL AS DRY AIR ADVECTION FROM THE SW NORTH ATLC BY EASTERLY-
SOUTHEASTERLY FLOW IS SUPPORTING FAIR WEATHER EAST OF THE
FRONTAL BOUNDARY N OF 21N. OVER THE COURSE OF 48 HOURS...THE
PORTION OF THE FRONT OVER THE WESTERN GULF WILL DRIFT NW WHILE
IT WEAKENS. FAIR WEATHER IS EXPECTED TO DOMINATE DURING THIS
PERIOD. A NEW COLD FRONT IS EXPECTED TO ENTER THE NW GULF WATERS
TUE MORNING.

CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL RIDGE COVERS THE WESTERN BASIN WHERE DRY
AIR SUBSIDENCE IS FAVORING FAIR WEATHER FOR THE MOST PART.
PATCHES OF LOW-LEVEL MOISTURE OBSERVED ON SSMI TPW IMAGERY
CONVERGE ALONG THE COASTLINES OF BELIZE...HONDURAS AND NICARAGUA
THUS ENHANCING SHOWERS WITHIN 70 NM OF THE COASTS. ISOLATED
SHOWERS ARE OBSERVED S OF 10N BEING ENHANCED BY THE MONSOON
TROUGH WHICH EXTENDS FROM COSTA RICA TO NORTHERN COLOMBIA. OVER
THE EASTERN BASIN...A MIDDLE TO UPPER LEVEL LOW SUPPORTS A
SURFACE TROUGH ANALYZED FROM 19N62W...ACROSS THE VIRGIN ISLANDS
SW TO 11N66W. MOISTURE ADVECTION FROM THE CENTRAL TROPICAL ATLC
SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS N OF
14N E OF 69W...INCLUDING PUERTO RICO...THE VIRGIN ISLANDS AND
LEEWARD ISLANDS. THE SURFACE TROUGH WILL CONTINUE TO MOVE
WESTWARD PRODUCING MORE RAINFALL ACROSS PUERTO RICO THROUGHOUT
MONDAY MORNING. RAINSHOWERS ASSOCIATED WITH THE TROUGH ARE
FORECAST TO START AFFECTING HISPANIOLA BY SUNDAY NIGHT.

HISPANIOLA...
FAIR WEATHER CONTINUES ACROSS THE ISLAND BEING SUPPORTED BY DRY
AIR SUBSIDENCE FROM THE MIDDLE LEVELS AS WELL AS DRY AIR
ADVECTION FROM THE SW NORTH ATLC. FAIR CONDITIONS ARE EXPECTED
TO PERSIST THROUGHOUT SUNDAY NIGHT WHEN RAINSHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ASSOCIATED WITH A SURFACE
TROUGH MOVING ACROSS THE CENTRAL CARIBBEAN SEA.

ATLANTIC OCEAN...
A 1027 MB HIGH IS CENTERED OVER THE W ATLANTIC NEAR 30N63W BEING
SUPPORTED BY A MIDDLE TO UPPER LEVEL RIDGE. VERY DRY AIR IS
OBSERVED ACROSS THIS REGION IN SSMI TPW IMAGERY WHICH IS
SUPPORTING FAIR WEATHER N OF 20N W OF 45W. OVER THE CENTRAL-
EASTERN ATLC...A 1002 MB LOW IS NEAR 31N39W. A COLD FRONT
ASSOCIATED WITH THIS LOW IS ANALYZED FROM 30N29W SW TO 21N35W TO
14N46W WHERE IT TRANSITIONS TO A SHEAR LINE TO 12N54W. NUMEROUS
MODERATE CONVECTION ASSOCIATED WITH THIS FRONTAL SYSTEM IS N OF
25N BETWEEN 24W-33W. SCATTERED SHOWERS AND TSTMS ARE N OF 24N
BETWEEN 35W-41W AND FROM 12N-16N BETWEEN 40W-51W. THERE IS A
GALE WARNING ASSOCIATED WITH THIS LOW PRESSURE SYSTEM. PLEASE
SEE SPECIAL FEATURE SECTION ABOVE.

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

$$
NR


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