000
AXNT20 KNHC 201137
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN DEC 20 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 FEATURE...

THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE CURRENTLY OVER THE
ATLC AND LOW PRESSURE OVER NW COLOMBIA IS SUPPORTING GALE FORCE
WINDS ACROSS THE S-CENTRAL CARIBBEAN FROM 10.5N-13N BETWEEN 73W-
78W. THE WINDS WILL DECREASE SLIGHTLY BELOW GALE FORCE BY 1800
UTC TODAY...AND ARE FORECAST TO PULSE BACK TO GALE FORCE AGAIN
LATER THIS EVENING. FOR MORE INFORMATION PLEASE REFER TO THE
HIGH SEAS FORECAST PRODUCT UNDER AWIPS/WMO HEADER
MIAHSFAT2/FZNT02 KNHC.   

...ITCZ/MONSOON TROUGH...
                                   
THE MONSOON TROUGH EXTENDS FROM 05N09W TO 04N14W...WHERE THE
ITCZ BEGINS AND EXTENDS TO 05N30W TO 03N40W TO 02N48W. ISOLATED
MODERATE CONVECTION IS WITHIN 100 NM OF EITHER SIDE OF THE ITCZ
AXIS. 

...DISCUSSION...

GULF OF MEXICO...                             

STRONG 1034 MB HIGH PRESSURE IS CENTERED OVER THE SE US
EXTENDING ACROSS THE ENTIRE GULF BASIN SUPPORTING MODERATE TO
FRESH E TO NE WINDS E OF 90W AND MODERATE SE WINDS W OF 90W. AN
UPPER RIDGE AXIS COVERS THE WESTERN GULF WITH DRY AIR IN THE MID
TO UPPER LEVELS AS WELL AS SUBSIDENCE OVER THE EASTERN HALF OF
THE GULF. STRATOCUMULUS COVERS MUCH OF THE BASIN ASIDE FROM THE
NE PORTION OF THE GULF...WITH ISOLATED LIGHT SHOWERS OCCURRING
OVER THE GULF S OF 25N. OVER THE NEXT 24 HOURS THE HIGH WILL
SLIDE E TO THE MID ATLC COAST OF THE E US...ALLOWING WINDS TO
VEER SLIGHTLY WITH MODERATE TO FRESH E TO SE WINDS PREVAILING
ACROSS THE ENTIRE BASIN BY MONDAY. 

CARIBBEAN SEA...       

AN UPPER TROUGH ALONG THE EASTERN US AND W ATLC SUPPORTS A COLD
FRONT ACROSS THE SW N ATLC TO CENTRAL CUBA NEAR 22N78W...WHERE
IT TRANSITIONS TO A STATIONARY FRONT TO 21N87W...AND THEN
TRANSITIONS TO A SURFACE TROUGH TO 17N88W. FRESH TO STRONG NE
WINDS ARE N OF THE STATIONARY FRONT. FRESH NE WINDS ARE S OF THE
STATIONARY FRONT. THE SURFACE TROUGH SUPPORTS ISOLATED MODERATE
CONVECTION WITHIN 75 NM OF THE TROUGH AXIS. ELSEWHERE ACROSS THE
CARIBBEAN...THE PRESSURE GRADIENT BETWEEN ATLC HIGH PRESSURE AND
LOW PRESSURE OVER NW COLOMBIA SUPPORTS GALE FORCE WINDS OVER THE
S-CENTRAL CARIBBEAN. PLEASE REFER TO THE SPECIAL FEATURES
SECTION FOR MORE DETAILS. FRESH TO STRONG TRADE WINDS ARE
OCCURRING S OF 15N BETWEEN 70W AND 80W. MODERATE TO FRESH TRADE
WINDS ARE ELSEWHERE OVER THE CENTRAL AND EASTERN CARIBBEAN. OVER
THE NEXT 24 HOURS THE GALE WINDS WILL PULSE OFF AND ON WITH
DIURNAL PRESSURE GRADIENT FLUCTUATIONS. CONVECTION WILL CONTINUE
ALONG THE COAST OF THE YUCATAN PENINSULA THROUGH THIS AFTERNOON
ASSOCIATED WITH THE TROUGH. 

...HISPANIOLA...  

A WEAK UPPER LEVEL DISTURBANCE OVER THE DOMINICAN REPUBLIC
SUPPORTS ISOLATED SHOWERS AND THUNDERSTORMS MAINLY OVER THE
EASTERN HALF OF HISPANIOLA. THIS FEATURE WILL CONTINUE TO
GENERATE SCATTERED SHOWERS AND THUNDERSTORMS OVER HISPANIOLA
THROUGH TONIGHT. 

ATLANTIC OCEAN...                          

AN UPPER TROUGH OVER THE E US AND W ATLC SUPPORTS A COLD FRONT
THAT ENTERS THE AREA OF DISCUSSION NEAR 31N60W TO 26N70W TO
22N78W. A PRE-FRONTAL TROUGH EXTENDS FROM 26N66W TO 23N72W.
SCATTERED SHOWERS ARE WITHIN 200 NM NW OF THE COLD FRONT.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE ALONG AND
WITHIN 90 NM SE OF THE COLD FRONT...AND WITHIN 75 NM OF EITHER
SIDE OF THE PRE-FRONTAL TROUGH. FARTHER EAST...A 1030 MB AREA OF
HIGH PRESSURE IS CENTERED NEAR 31N38W. AN UPPER TROUGH OVER THE
EASTERN ATLC SUPPORTS A COLD FRONT FROM 32N12W TO 27N21W WHERE
IT TRANSITIONS TO A STATIONARY FRONT TO 23N30W TO 22N40W TO
22N50W. NO DEEP CONVECTION IS NOTED. A SURFACE TROUGH IS OVER
THE TROPICAL CENTRAL ATLC WITH AN AXIS EXTENDING FROM 07N50W TO
03N50W. ISOLATED MODERATE CONVECTION IS WITHIN 250 NM OF EITHER
SIDE OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH IS OVER THE E
ATLC EXTENDING FROM 28N12W TO 21N17W. NO DEEP CONVECTION IS
NOTED. 

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

$$

LATTO