[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...SPECIAL FEATURE...

THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE CURRENTLY OVER THE
ATLC AND LOW PRESSURE OVER NW COLOMBIA CONTINUE TO SUPPORT GALE
FORCE WINDS ACROSS THE S-CENTRAL CARIBBEAN FROM 10.5N TO 13N
BETWEEN 73W AND 78W WITH SEAS RANGING FROM 10 TO 14 FT. NE TO E
WINDS OF 20 TO 30 KT ARE ELSEWHERE FROM 10N TO 17N BETWEEN 69W
AND 83W WITH SEAS FROM 8 TO 11 FT. THE WINDS WILL DECREASE
SLIGHTLY BELOW GALE FORCE DURING THE AFTERNOON...BUT WILL 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 ITCZ EXTENDS FROM 04N08W TO 04N36W TO 05N52W. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE FROM 03N TO 06N BETWEEN 25W AND
40W. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE ITCZ
ELSEWHERE.

...DISCUSSION...

GULF OF MEXICO...

A STRONG AND BROAD RIDGE ANCHORED BY A 1037 MB HIGH OVER NORTH
CAROLINA EXTENDS SW ACROSS THE GULF...THUS PROVIDING MODERATE TO
FRESH E TO SE WINDS OVER THE NORTHERN BASIN. THE TAIL OF A
STATIONARY FRONT EXTENDS FROM WESTERN CUBA TO THE NORTHERN
YUCATAN PENINSULA. A TIGHT PRESSURE GRADIENT BETWEEN THE RIDGE
AND THE FRONT SUPPORTS NE FRESH TO STRONG WINDS IN THE SE GULF
AND NE MODERATE TO FRESH WINDS OVER THE SW BASIN. DRY AIR IN THE
MID TO UPPER LEVELS AS WELL AS SUBSIDENCE SUPPORT FAIR WEATHER
BASIN-WIDE. ISOLATED SHOWERS ARE POSSIBLE OVER THE SE BASIN S OF
24N ASSOCIATED WITH THE FRONT. BY LATE TODAY THE FRONT WILL
DISSIPATE WHILE THE HIGH WILL SLIDE E TO THE MID ATLC
WATERS...THUS ALLOWING WINDS TO VEER SLIGHTLY THROUGH EARLY WED.

CARIBBEAN SEA...

THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE CURRENTLY OVER THE
ATLC AND LOW PRESSURE OVER NW COLOMBIA CONTINUE TO SUPPORT GALE
FORCE WINDS ACROSS THE S-CENTRAL CARIBBEAN AND MODERATE TO FRESH
WINDS ACROSS MOST OF THE REMAINDER BASIN. GALE WINDS ARE
EXPECTED TO PULSE AT NIGHT THROUGH TUE. PLEASE REFER TO THE
SPECIAL FEATURES SECTION FOR MORE DETAILS. AN UPPER TROUGH ALONG
THE EASTERN CONUS SEABOARD EXTENDING TO A BASE OVER HONDURAS AND
NICARAGUA SUPPORTS A WEAK STATIONARY FRONT FROM WESTERN
CUBA...ACROSS THE YUCATAN CHANNEL TO THE NORTHERN YUCATAN
PENINSULA. OFF THE YUCATAN PENINSULA AND BELIZE A PRE-FRONTAL
TROUGH IS ANALYZED FROM 20N86W TO 15N88W ENHANCING ISOLATED
SHOWERS W OF 85W. SIMILAR SHOWER ACTIVITY IS BETWEEN SOUTHERN
PANAMA AND COLOMBIA BEING ENHANCED BY A 1008 MB LOW NEAR 08N76W.
SHALLOW MOISTURE AND A DIFFLUENT ENVIRONMENT ALOFT SUPPORT
ISOLATED SHOWERS AND TSTMS OVER HISPANIOLA AND PASSING SHOWERS
ACROSS PUERTO RICO. ELSEWHERE FAIR WEATHER DOMINATES SUPPORTED
BY DRY AIR SUBSIDENCE.

...HISPANIOLA...

SHALLOW MOISTURE AND A DIFFLUENT ENVIRONMENT ALOFT SUPPORT
ISOLATED SHOWERS AND TSTMS OVER HISPANIOLA...MAINLY OVER
DOMINICAN REPUBLIC. THIS FEATURE WILL CONTINUE TO GENERATE
SCATTERED SHOWERS AND THUNDERSTORMS OVER HISPANIOLA THROUGH
TONIGHT.

ATLANTIC OCEAN...

AN UPPER TROUGH ALONG THE EASTERN CONUS SEABOARD EXTENDING TO A
BASE OVER HONDURAS AND NICARAGUA SUPPORTS A WEAK STATIONARY
FRONT FROM 30N59W TO THE CENTRAL BAHAMAS NEAR 23N75W TO WESTERN
CUBA NEAR 22N79W. DIFFLUENCE ALOFT SUPPORTS SCATTERED SHOWERS
AND TSTMS FROM 20N TO 27N BETWEEN 68W AND 76W. FRESH TO STRONG
NE WINDS ARE BEHIND THE FRONT. ISOLATED SHOWERS ARE WITHIN 100
NM ELSEWHERE W ALONG THE FRONT. A DISSIPATING COLD FRONT EXTENDS
FROM 30N10W TO 22N28W WHERE IT TRANSITIONS TO A DISSIPATING
STATIONARY FRONT TO 22N56W...NO CONVECTION ASSOCIATED WITH IT.
SURFACE RIDGING DOMINATES ELSEWHERE.

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

$$
NR
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