000
AXNT20 KNHC 200607
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 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 11N-13N BETWEEN 73W-
77W. THE WINDS WILL DECREASE SLIGHTLY BELOW GALE FORCE BY 1200
UTC THIS MORNING...AND ARE FORECAST TO PULSE BACK TO GALE FORCE
AGAIN 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 04N13W...WHERE THE
ITCZ BEGINS AND EXTENDS TO 03N30W TO 03N40W TO 04N48W. ISOLATED
MODERATE CONVECTION IS WITHIN 120 NM OF EITHER SIDE OF THE ITCZ
AXIS. 

...DISCUSSION...

GULF OF MEXICO...                             

STRONG 1034 MB HIGH PRESSURE IS CENTERED OVER THE TENNESSEE
VALLEY EXTENDING ACROSS THE ENTIRE GULF BASIN SUPPORTING
MODERATE TO FRESH E TO NE WINDS E OF 93W AND MODERATE SE WINDS W
OF 93W. 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. A LARGE AMOUNT OF STRATOCUMULUS COVERS
THE BASIN ASIDE FROM THE NE PORTION OF THE GULF...WITH ONLY
ISOLATED LIGHT SHOWERS OCCURRING OVER THE GULF S OF 23N. 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 22N80W TO
22N82W...WHERE IT TRANSITIONS TO A STATIONARY FRONT TO
21N87W...AND THEN TRANSITIONS TO A SURFACE TROUGH TO 16N88W.
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 TRADES 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 SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE
EASTERN THIRD OF HISPANIOLA TONIGHT. THIS FEATURE WILL CONTINUE
TO GENERATE SCATTERED SHOWERS AND THUNDERSTORMS OVER HISPANIOLA
THROUGH SUN NIGHT. 

ATLANTIC OCEAN...                          

AN UPPER TROUGH OVER THE E US AND W ATLC SUPPORTS A COLD FRONT
THAT ENTERS THE AREA OF DISCUSSION NEAR 31N63W TO 27N70W TO
22N79W. A PRE-FRONTAL TROUGH EXTENDS FROM 26N66W TO 23N72W.
SCATTERED SHOWERS ARE WITHIN 150 NM NW OF THE COLD FRONT.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE ALONG AND
WITHIN 50 NM SE OF THE COLD FRONT...AND WITHIN 75 NM OF EITHER
SIDE OF THE PRE-FRONTAL TROUGH. FARTHER EAST...A 1032 MB AREA OF
HIGH PRESSURE IS CENTERED NEAR 31N39W. AN UPPER TROUGH OVER THE
EASTERN ATLC SUPPORTS A COLD FRONT FROM 32N12W TO 26N25W WHERE
IT TRANSITIONS TO A STATIONARY FRONT TO 22N40W TO 23N53W. NO
DEEP CONVECTION IS NOTED. A SURFACE TROUGH IS OVER THE TROPICAL
CENTRAL ATLC WITH AN AXIS EXTENDING FROM 07N49W TO 04N49W.
ISOLATED MODERATE CONVECTION IS WITHIN 150 NM OF EITHER SIDE OF
THE TROUGH AXIS. ANOTHER SURFACE TROUGH IS OVER THE E ATLC
EXTENDING FROM 29N15W TO 25N20W. NO DEEP CONVECTION IS NOTED. 

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

$$

LATTO