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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 110557
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL 
105 AM EST WED DEC 11 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.

...SPECIAL FEATURE...                                           
GALE WARNING CURRENTLY IN EFFECT FOR THE GULF OF MEXICO S OF 22N 
W OF 95W IN ASSOCIATION WITH A COLD FRONT THAT AT 11/0300 UTC 
EXTENDS FROM 28N83W TO 22N94W TO 18N94W. SEE LATEST NHC 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 EAST 
TROPICAL ATLC NEAR 09N13W TO 07N18W. THE ITCZ AXIS EXTENDS FROM 
07N18W TO 04N30W TO 02N40W. SCATTERED MODERATE CONVECTION IS 
MAINLY N OF THE AXES FROM 11N-20N E OF 28W...FROM 05N-11N 
BETWEEN 28W-46W AND FROM 01N-06N BETWEEN 27W-32W. 

...DISCUSSION...

GULF OF MEXICO...                                                
A MIDDLE TO UPPER LEVEL BROAD TROUGH WITH AXIS EXTENDING FROM 
MAINE SW TO CENTRAL FLORIDA SUPPORTS A COLD FRONT ANALYZED FROM 
WESTERN-CENTRAL FLORIDA NEAR 27N82W SW TO 23N90W TO THE BAY OF 
CAMPECHE NEAR 18N93W. A HIGH PRESSURE SYSTEM ACROSS THE LOWER 
MISSISSIPPI VALLEY AND EASTERN SOUTHERN PLAINS EXTENDS A RIDGE 
AXIS INTO THE GULF AND SUPPLIES NORTHEASTERLY WIND FLOW TO THE 
BASIN. A TIGHT PRESSURE GRADIENT BEHIND THE COLD FRONT IN THE SW 
GULF SUPPORT GALE FORCE WINDS THAT ARE FORECAST TO SUBSIDE AT 
11/0600 UTC. SEE SPECIAL FEATURES SECTION FOR MORE DETAILS. SSMI 
TPW IMAGERY DEPICT DRY AIR OVER THE BASIN WHICH IS SUSTAINING 
FAIR WEATHER. WITHIN 24 HOURS...THE PORTION OF THE COLD FRONT 
OVER THE GULF IS FORECAST TO STALL AND SLOWLY DISSIPATE. HIGH 
PRESSURE AND NORTHEASTERLY WIND FLOW ARE EXPECTED TO 
CONTINUE ACROSS THE GULF THROUGHOUT FRIDAY MORNING.

CARIBBEAN SEA...                                                 
A MIDDLE-LEVEL INVERTED TROUGH WEST OF 72W CONTINUES TO SUPPORT 
A SURFACE TROUGH ANALYZED FROM 20N83W TO 14N83W. LOW-LEVEL 
MOISTURE CONVERGENCE ALONG THE TROUGH AXIS AND UPPER-LEVEL 
DIVERGENCE SUPPORT SCATTERED RAINSHOWERS AND ISOLATED TSTMS FROM 
14N-21N BETWEEN 78W-86W. ALOFT AND ACROSS THE REMAINDER BASIN 
WESTERLY WIND FLOW AND DRY AIR SUBSIDENCE DOMINATE. SSMI TPW 
IMAGERY SHOW ADVECTION OF VERY DRY AIR FROM THE CENTRAL ATLC 
ACROSS THE EASTERN BASIN WHICH ALONG WITH MIDDLE LEVEL DRY AIR 
SUPPORT FAIR WEATHER. OTHERWISE...A RELATIVELY TIGHT PRESSURE 
GRADIENT OVER THE CENTRAL-EASTERN BASIN SUPPORTS 20-25 KT WINDS 
EXPECTED TO PERSIST THROUGHOUT FRI MORNING. THE SURFACE TROUGH 
WILL CONTINUE A WESTWARD TRACK AND IS FORECAST TO MOVE ACROSS 
CENTRAL AMERICA BY WED AFTERNOON.

HISPANIOLA...                                                 
FAIR WEATHER DOMINATES ACROSS THE ISLAND BEING SUPPORTED BY DRY 
AIR SUBSIDENCE FROM THE MIDDLE LEVELS AS WELL AS DRY AIR 
ADVECTION FROM THE NORTH-CENTRAL ATLC. FAIR WEATHER IS EXPECTED 
TO PERSIST THROUGHOUT FRI MORNING AS MULTI-LAYERED DRY AIR WILL 
CONTINUE TO MOVE ACROSS THE ISLAND. HOWEVER...AFTERNOON/EARLY 
EVENING SHOWERS ARE LIKELY WITHIN THAT TIME FRAME.

ATLANTIC OCEAN...                                                
A MIDDLE TO UPPER LEVEL BROAD TROUGH WITH AXIS EXTENDING FROM 
MAINE SW TO CENTRAL FLORIDA SUPPORTS A COLD FRONT ANALYZED FROM 
30N75W SW TO EASTERN-CENTRAL FLORIDA NEAR 27N80W. VERY DRY AIR 
ACROSS THE SW NORTH ATLC HINDERS CONVECTION AT THE TIME. FARTHER 
EAST AND OVER THE CENTRAL ATLC...A 1027 MB HIGH IS NEAR 30N52W 
WHICH IS EXPECTED TO DRIFT SE OVER THE NEXT 24 HOURS MAINTAINING 
FAIR WEATHER CONDITIONS. A MIDDLE TO UPPER LEVEL TROUGH ACROSS 
THE EASTERN ATLC SUPPORTS A COLD FRONT ANALYZED FROM 30N20W TO 
22N31W TO 20N44W. FARTHER EAST...THE SAME TROUGH ALOFT SUPPORTS 
A SURFACE TROUGH EXTENDING ALONG 30N18W TO 20N24W. SCATTERED 
SHOWERS AND TSTMS ASSOCIATED WITH THIS LOW PRESSURE SYSTEM ARE N 
OF 24N BETWEEN 13W-20W.

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

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