Tropical Weather Discussion
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000
AXNT20 KNHC 211713
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN DEC 21 2014

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
1700 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH CROSSES THE COAST OF AFRICA NEAR 05N09W TO
06N14W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 05N30W 05N40W
TO THE COAST OF SURINAME NEAR 04N51W. ISOLATED MODERATE
CONVECTION IS FROM 03N-09N E OF 30W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 03N-08N W OF 30W.

...DISCUSSION...

GULF OF MEXICO...

SOUTHWESTERLY FLOW ALOFT BETWEEN A MIDDLE-LEVEL TROUGH WITH AXIS
ALONG THE CENTRAL U.S. AND A BROAD ANTICYCLONE ANCHORED N OF THE
MONA PASSAGE CONTINUES TO ADVECT MOISTURE FROM THE EPAC ITCZ TO
THE GULF N OF A LINE FROM 28N82W TO 25N90W TO 18N95W. AHEAD OF
THIS PLUME OF MOISTURE STREAMING INTO THE GULF...A STATIONARY
FRONT EXTENDS FROM ACROSS NORTHERN FLORIDA TO 28N85W SW TO THE
GULF OF CAMPECHE ALONG 25N92W TO 20N96W. THE WIND PATTERN ALOFT
ALLOWS FOR A DIFFLUENT ENVIRONMENT THAT ENHANCES SCATTERED
SHOWERS AND ISOLATED TSTMS N OF THE FRONTAL BOUNDARY. A PRE-
FRONTAL SURFACE TROUGH IS FROM 26N86W TO 21N87W SUPPORTING
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS WITHIN 160 NM E
OF ITS AXIS FROM 21N-25N. OTHERWISE...VARIABLE WIND OF 5-15 KT
DOMINATE THE GULF WATERS. THE STATIONARY FRONT WILL WEAKEN
TONIGHT ALONG WITH THE SURFACE TROUGH AS HIGH PRESSURE BUILDING
IN THE SW N ATLC EXTENDS A RIDGE AXIS SW ACROSS THE GULF. A
STRONG COLD FRONT WILL BE ENTERING THE NW BASIN TUESDAY NIGHT
WITH GALE FORCE WINDS N OF THE BOUNDARY.

CARIBBEAN SEA...

A VERY STABLE ENVIRONMENT CONSISTING OF A BROAD MIDDLE-LEVEL
ANTICYCLONE...A RIDGE AT THE UPPER-LEVELS AND DRY AIR SUBSIDENCE
FROM ALOFT SUPPORTS FAIR WEATHER ACROSS GREAT PORTIONS OF THE
BASIN. SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW MAY
ENHANCE ISOLATED SHOWERS ACROSS THE CENTRAL AND EASTERN BASIN
WHILE A SURFACE TROUGH ALONG 18N82W TO 10N82W ENHANCE SIMILAR
SHOWER ACTIVITY S OF 18N WITHIN 100 NM OF THE CENTRAL AMERICA
COAST. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE IN
THE YUCATAN CHANNEL ASSOCIATED WITH A SURFACE TROUGH IN THE SE
GULF OF MEXICO WHICH WILL DISSIPATE THIS EVENING LEAVING
LINGERING SHOWERS THROUGH LATE TONIGHT. LIGHT TRADES OF 5-10 KT
ARE IN THE NW CARIBBEAN WHILE TRADES OF 15-20 KT DOMINATE
ELSEWHERE...INCREASING TO 25 KT ALONG THE COAST OF COLOMBIA.
TRADES OVER THE CENTRAL AND EASTERN CARIBBEAN ARE FORECAST TO
REMAIN ON THE 20-25 KT THE NEXT THREE DAYS...HOWEVER SPREADING
WESTWARD TO THE REMAINDER BASIN AS HIGH PRESSURE OVER
THE SW N ATLC STRENGTHENS FROM MON TO TUE.

HISPANIOLA...

A VERY STABLE ENVIRONMENT ALOFT CONTINUES TO SUPPORT FAIR
WEATHER ACROSS THE ISLAND...HOWEVER A SHALLOW MOIST AIRMASS OVER
THE EASTERN BASIN CARIBBEAN WILL START MOVING ACROSS THE CENTRAL
AND SOUTHERN ISLAND TONIGHT...THUS SUPPORTING CLOUDINESS AND
POSSIBLE ISOLATED SHOWERS THROUGH MONDAY AFTERNOON.

ATLANTIC OCEAN...

A STATIONARY FRONT CONTINUES TO EXTEND FROM THE GULF OF MEXICO
ACROSS THE NORTHERN FLORIDA PENINSULA REACHING THE SW N ATLC
WATERS FROM 29N81W TO 30N76W. THE CURRENT OF UPPER-LEVEL
MOISTURE ACROSS THE GULF OF MEXICO REACHES THIS PORTION OF THE
ATLC...THUS SUPPORTING ISOLATED SHOWERS N OF 22N W OF 70W. OVER
THE CENTRAL BASIN...A NARROW AND ELONGATED TROUGH ALOFT WITH
BASE NEAR 25N36W SUPPORT A COLD FRONT N OF THE AREA OF
DISCUSSION THAT STARTS TO DISSIPATE ALONG 29N41W SW TO 23N50W.
AHEAD OF THE FRONT...A SURFACE TROUGH EXTENDS FROM 30N38W TO
23N38W ENHANCING SCATTERED MODERATE CONVECTION AND ISOLATED
TSTMS WITHIN 90 NM EITHER SIDE OF ITS AXIS. SURFACE RIDGING
DOMINATES OVER THE EASTERN BASIN N OF 22N. SURFACE RIDGING WILL
BECOME THE DOMINANT FEATURE ACROSS THE ENTIRE ATLC BY TUE NIGHT.

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

$$
RAMOS



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