Atlantic Tropical Weather Discussion

000
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 
WWW.HURRICANES.GOV/MARINE

$$
NR