Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 311116
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
705 AM EST SAT JAN 31 2015

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 FEATURES...

ATLANTIC...GALE-FORCE WINDS ARE FORECAST TO DEVELOP TONIGHT N OF 
29N BEHIND A COLD FRONT THAT IS FORECAST TO EXTEND FROM 31N53W 
TO 25N60W. SEAS WILL BUILD TO 12 TO 20 FT. SEE THE HIGH SEAS 
FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE 
INFORMATION.

CARIBBEAN...GALE-FORCE WINDS FROM 10.5N TO 13N BETWEEN 73.5W AND 
78W WILL DECREASE BELOW GALE-FORCE BY 1200 UTC THIS MORNING. 
WINDS WILL INCREASE BACK TO GALE-FORCE SUNDAY MORNING. SEE THE 
HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC 
FOR MORE INFORMATION. 

...ITCZ/MONSOON TROUGH...                                     

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC NEAR 08N13W TO 04N19W WHERE THE ITCZ BEGINS AND CONTINUES 
ALONG 01N30W TO 00N45W. ISOLATED MODERATE CONVECTION IS WITHIN 
100 NM OF THE ITCZ BETWEEN 22W AND 41W. 

...DISCUSSION...

GULF OF MEXICO...

AN UPPER TROUGH WITH AXIS ALONG 65W AND BASE ALONG 30N SUPPORTS 
A LOW PRESSURE SYSTEM OVER THE NW ATLC FROM WHICH A COLD FRONT 
EXTENDS SW CROSSING SOUTH FLORIDA AND THEN THE GULF FROM 26N81W 
TO 25N91W WHERE IT TRANSITIONS TO A STATIONARY FRONT THAT 
EXTENDS TO NEAR THE TX/MEXICO BORDER AT 26N97W. DRY AIR AND 
SUBSIDENCE IS INHIBITING CONVECTION ACROSS THE BASIN...WITH 
ISOLATED SHOWERS WITHIN 30 NM OF THE FRONTAL BOUNDARIES. E TO NE 
WINDS OF 15 TO 20 KT ARE N OF THE FRONTS. SLIGHTLY WEAKER E TO 
NE WINDS OF 10 TO 15 KT ARE S OF THE FRONTS. THE EASTERN PORTION 
OF THE COLD FRONT WILL CONTINUE TO MOVE SE ACROSS THE FL STRAITS 
TODAY AND OVER CUBA TONIGHT. THE PORTION OF THE FRONT OVER THE W 
GULF WILL GRADUALLY TRANSITION TO A WARM FRONT TODAY AND LIFT 
NORTH TOWARD THE TX/LA COAST OVERNIGHT TONIGHT. 

CARIBBEAN SEA...

A STRONG PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE SE US  
AND LOWER PRESSURE OVER S AMERICA IS PRODUCING GALE-FORCE WINDS 
N OF COLOMBIA. SEE THE SPECIAL FEATURES SECTION FOR MORE 
DETAILS. THIS PRESSURE GRADIENT ALSO SUPPORTS NE WINDS OF 15 TO 
20 KT OVER THE REMAINDER OF THE BASIN. ALTHOUGH DRY AIR ALOFT IS 
INHIBITING DEEP CONVECTION ACROSS THE BASIN...LOW LEVEL MOISTURE 
SUPPORTS SHOWERS WITHIN 170 NM OF THE N COAST OF HONDURAS AS 
WELL AS OVER JAMAICA AND HISPANIOLA. OVER THE NEXT 24 HOURS A 
COLD FRONT WILL MOVE OVER CUBA AND BECOME STATIONARY. SHOWERS 
WILL BE POSSIBLE SOUTH OF THIS FRONT OVER THE EXTREME NW 
PORTIONS OF THE CARIBBEAN. 

...HISPANIOLA... 

REMNANT MOISTURE FROM A DISSIPATED FRONTAL BOUNDARY CONTINUES TO 
ENHANCE SHOWERS OVER THE ISLAND. ANOTHER COLD FRONT MOVING SE 
INTO THE AREA IS FORECAST TO STALL OUT AND DISSIPATE IN THE 
VICINITY OF THE ISLAND MONDAY MORNING. THIS WILL BRING 
ADDITIONAL ENHANCED SHOWER ACTIVITY TO THE AREA FOR THE NEXT 
COUPLE OF DAYS.  

ATLANTIC OCEAN...

AN UPPER TROUGH WITH AXIS ALONG 70W AND BASE ALONG 30N SUPPORTS 
A LOW PRESSURE SYSTEM OVER THE NW ATLC FROM WHICH A COLD FRONT 
EXTENDS AND ENTERS THE AREA OF DISCUSSION FROM 31N67W SW TO 
SOUTH FLORIDA NEAR 26N81W. GALE-FORCE WINDS ARE FORECAST TO 
DEVELOP W OF THE FRONT N OF 29N. SEE THE SPECIAL FEATURES 
SECTION FOR DETAILS. FARTHER EAST...A DISSIPATING STATIONARY 
FRONT EXTENDS FROM 31N53W TO 20N66W. SCATTERED SHOWERS AND 
ISOLATED THUNDERSTORMS ARE WITHIN 100 NM E OF THE FRONT. A PRE-
FRONTAL SURFACE TROUGH EXTENDS FROM 31N51W TO 26N53W. SCATTERED 
MODERATE CONVECTION IS FROM 27N TO 31N BETWEEN 48W AND 51W. AN 
UPPER LOW CENTERED NEAR 27N35W IS INTERACTING WITH A SURFACE 
TROUGH EXTENDING FROM 27N36W TO 22N39W WHICH IS GENERATING 
WIDELY SCATTERED MODERATE CONVECTION FROM 24N TO 29N BETWEEN 32W 
AND 37W. SURFACE HIGH PRESSURE OF 1032 MB CENTERED NEAR 40N32W 
DOMINATES THE REMAINDER OF THE CENTRAL AND EASTERN ATLANTIC. 
OVER THE NEXT 36 HOURS THE COLD FRONT WILL MOVE QUICKLY E TO THE 
CENTRAL ATLANTIC. THE STATIONARY FRONT WILL DISSIPATE TODAY.  

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

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LATTO