Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 050003
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
705 PM EST WED DEC 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR 
07N12W TO 06N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS 
EXTENDS FROM 06N22W TO 06N32W TO 07N43W. SCATTERED MODERATE 
CONVECTION AND TSTMS ARE FROM 01N-09N BETWEEN 13W-23W. ISOLATED 
MODERATE CONVECTION AND TSTMS ARE FROM 05N-13N BETWEEN 25W-
40W.

...DISCUSSION...

GULF OF MEXICO...                                                
WESTERLY TO NORTHWESTERLY MIDDLE TO UPPER LEVEL WIND FLOW IS 
NOTED ON WATER VAPOR IMAGERY ASSOCIATED WITH AN ANTICYCLONIC 
CIRCULATION CENTERED OVER THE SOUTHERN GULF NEAR 19N91W. MOSTLY 
DRY AIR AND UPPER-LEVEL STABILITY SUPPORT FAIR WEATHER 
CONDITIONS. AT THE SURFACE...SOUTHERLY RETURN FLOW IN THE RANGE 
OF 10 TO 15 KT DOMINATES. OVER THE NORTHERN GULF...MOISTURE 
ADVECTION FROM THE E PACIFIC BY THE ANTICYCLONE ALOFT AS WELL AS 
UPPER-LEVEL DIFFLUENCE SUPPORT RAINSHOWERS N OF 28 BETWEEN 85W-
89W. ISOLATED SHOWERS ARE ALSO IN THE NW GULF N OF 27N W OF 94W. 
A COLD FRONT CURRENTLY ANALYZED OVER THE SOUTHERN PLAINS IS 
FORECAST TO MOVE SOUTHEASTWARD THROUGH LATE THURSDAY AND EMERGE 
OFF THE TEXAS AND LOUISIANA COASTS BY EARLY TO MID-DAY FRIDAY 
INTO SATURDAY. 

CARIBBEAN SEA...                                              
NORTH-NORTHWESTERLY DRY AND STABLE WIND FLOW IN THE MIDDLE 
LEVELS IS NOTED W OF 70W ON WATER VAPOR IMAGERY WHICH CONTINUE 
TO SUPPORT CLEAR SKIES AND FAIR WEATHER ACROSS THIS REGION OF 
THE BASIN. OVER THE SW BASIN WITHIN 70 NM OF THE PANAMA CANAL 
BETWEEN 78W-82W...SCATTERED SHOWERS ARE BEING ENHANCED BY THE 
MONSOON TROUGH AXIS WHICH EXTENDS ACROSS NORTHERN PANAMA TO 
NORTHERN COLOMBIA NEAR 06N74W. A MIDDLE TO UPPER LEVEL TROUGH 
EXTENDS FROM NOVA SCOTIA SOUTHWARD TO THE EASTERN CARIBBEAN AND 
SUPPORTS A SURFACE PRE-FRONTAL TROUGH CURRENTLY BEING ANALYZED 
FROM 23N61W TO NE PUERTO RICO NEAR 18N65W TO S OF DOMINICAN 
REPUBLIC NEAR 16N70W. AN ELONGATED MIDDLE TO UPPER LEVEL RIDGE 
EXTENDS FROM THE CENTRAL ATLC TO THE LESSER ANTILLES TO GENERATE 
DIFFLUENCE ALOFT AND SUPPORT RAINSHOWERS ACROSS DOMINICAN 
REPUBLIC...MONA PASSAGE...PUERTO RICO...THE VIRGIN ISLANDS AND 
NORTHERN LEEWARD ISLANDS. A WEAK PRESSURE GRADIENT ACROSS THE 
BASIN IS FORECAST TO PROVIDE WITH TRADEWINDS IN THE RANGE OF 10-
15 KT THROUGHOUT THU MORNING. AFTERWARDS...A TIGHTER PRESSURE 
GRADIENT IS EXPECTED TO DEVELOP SUPPORTING EASTERLY WINDS UP TO 
20 KT ACROSS THE CENTRAL BASIN THROUGHOUT FRI NIGHT.

...HISPANIOLA...                                                
A SURFACE TROUGH IS BEING ANALYZED FROM 23N61W IN THE ATLC TO NE 
PUERTO RICO NEAR 18N65W TO S OF DOMINICAN REPUBLIC NEAR 16N70W. 
THIS AREA OF LOW PRESSURE IS SUPPORTING RAINSHOWERS ACROSS 
DOMINICAN REPUBLIC AND SOUTHERN ADJACENT WATERS TO 14N AS WELL 
AS THE MONA PASSAGE. THE BOUNDARY IS FORECAST TO REMAIN 
RELATIVELY STATIONARY OVER THE NEXT 24 HOURS AND GRADUALLY 
DISSIPATE. HOWEVER RAINSHOWERS AND TSTMS ARE FORECAST TO PERSIST 
ACROSS EASTERN PORTIONS OF THE ISLAND THROUGHOUT FRI NIGHT.

ATLANTIC OCEAN...                                               
A BROAD MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM NOVA SCOTIA 
SOUTHWARD TO THE EASTERN CARIBBEAN AND SUPPORTS A COLD FRONT 
ANALYZED FROM 30N54W TO 25N60W TO 23N65W AS WELL AS A PRE-
FRONTAL TROUGH FROM 23N61W TO NE PUERTO RICO NEAR 18N65W TO S OF 
DOMINICAN REPUBLIC NEAR 16N70W. AN ELONGATED MIDDLE TO UPPER 
LEVEL RIDGE EXTENDS FROM THE CENTRAL ATLC TO THE LESSER ANTILLES 
TO GENERATE DIFFLUENCE ALOFT AND SUPPORT SCATTERED MODERATE 
CONVECTION/ISOLATED TSTMS N OF 24N BETWEEN 47W-60W AND WITHIN 
260 NM E OF THE TROUGH AXIS FROM 18N-23N. THE REMAINDER OF THE 
SW NORTH ATLC WEST OF THE COLD FRONT IS UNDER THE INFLUENCE OF 
RELATIVELY DRY AND STABLE NORTHWESTERLY FLOW ALOFT AND A SURFACE 
RIDGE ANCHORED BY A 1021 MB HIGH CENTERED OFF THE COAST OF THE 
CAROLINAS NEAR 34N70W. A DEEP LAYERED LOW IS CENTERED OVER THE 
EASTERN ATLC NEAR 31N28W WITH THE SURFACE LOW ANALYZED AT 996 
MB. THE OCCLUDED LOW HAS A TRIPLE POINT IN THE VICINITY OF THE 
MADEIRA ISLANDS NEAR 34N18W WITH A WARM FRONT STRETCHING SE TO  
31N14W AND A DISSIPATING COLD FRONT EXTENDING SW FROM THE TRIPLE 
POINT TO 21N28W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING MAINLY 
WITHIN 240 NM OF THE LOW CENTER.

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

$$
RAMOS