[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED DEC 25 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH IS OVER AFRICA. THE INTERTROPICAL CONVERGENCE
ZONE AXIS EXTENDS FROM 06N11W TO 04N20W TO 04N30W TO 04N40W TO
03N15W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS
WITHIN 120 NM N OF THE ITCZ W OF 40W. WIDELY SCATTERED MODERATE
CONVECTION IS SEEN FROM 04N-07N BETWEEN 20W-26W...AND ALSO
WITHIN 60-90 NM N OF THE ITCZ BETWEEN 31W-37W.

...DISCUSSION...

GULF OF MEXICO...
IN THE UPPER LEVEL...SOUTHWESTERLY UPPER LEVEL WINDS ARE NOTED
DUE TO AN UPPER LEVEL TROUGH SEE ON WATER VAPOR IMAGERY WITH
AXIS ROUGHLY ALONG 106W. THIS UPPER FLOW IS KEEPING THE
ATMOSPHERE OVER MUCH OF THE GULF RATHER MOIST AS NOTED BY THE
MOSTLY OVERCAST TO BROKEN LOW AND MID LEVEL CLOUDS W OF ABOUT
90W WITH BROKEN TO OVERCAST HIGH LEVEL CLOUDS STREAMING NEWD
ALOFT. PATCHES OF RAIN ARE UNDERNEATH THESE CLOUDS. ELSEWHERE
...BROKEN TO SCATTERED LOW CLOUDS WITH SCATTERED TO WIDELY
SCATTERED SHOWERS ATTRIBUTED TO MOISTURE FROM A STALLED OUT
FRONTAL BOUNDARY ACROSS THE STRAITS OF FLORIDA ARE SEEN OVER THE
MIDDLE AND EASTERN PORTIONS OF THE GULF.

AT THE SURFACE...A RIDGE REMAINS IN PLACE WITH AXIS EXTENDING
FROM THE OHIO RIVER VALLEY S-SW TO THE LOWER MISSISSIPPI RIVER
VALLEY AND TO ALONG THE EASTERN MEXICO GULF COAST. A 1024 MB
HIGH IS INLAND MEXICO NEAR 23N100W. THE RESULTANT PRES GRADIENT
BETWEEN THE RIDGE AND STALLED OUT FRONT OVER THE STRAITS OF
FLORIDA WILL ALLOW FOR NE WINDS GENERALLY IN THE RANGE OF 10-15
KT WITH POCKETS OF 15-20 KT WINDS IN THE WESTERN GULF THROUGH
TONIGHT. THE PRES GRADIENT IS THEN EXPECTED TO STRENGTHEN EARLY
ON THU AS ANOTHER SURFACE RIDGE SAGS SOUTHEASTWARD FROM THE
SOUTHERN PLAINS STATES AND LOWER MISSISSIPPI RIVER VALLEY...AND
INTERACTS WITH THE REMNANTS OF THE STALLED OUT FRONT AS IT
DRIFTS WESTWARD THROUGH FRI. WEAK LOW PRES IS EXPECTED TO
DEVELOP IN THE CENTRAL GULF BEGINNING ON FRI IN RESPONSE TO A
SHORTWAVE TROUGH THAT EVOLVES FROM AFOREMENTIONED UPPER
TROUGH...AND THEN MOVES ACROSS THE GULF.

CARIBBEAN SEA...
SATELLITE WATER VAPOR IMAGERY SHOWS A PERSISTENT MID/UPPER LEVEL
LOW OVER THE EASTERN CARIBBEAN NEAR 16N65W. THE IMAGERY
CONTINUES TO DEPICT VERY DRY AND STABLE AIR ON THE WESTERN
PERIPHERY OF THE UPPER LEVEL LOW WHILE TO ITS E AND SE
...PRACTICALLY ACROSS THE ENTIRE PORTION OF THE EASTERN PART OF
THE SEA...ABUNDANT DEEP ATMOSPHERIC MOISTURE IS OBSERVED.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE QUITE PREVALENT OVER IN
THAT PORTION OF THE SEA. A RATHER BROAD SURFACE TROUGH IS ALONG
69W...WITH ISOLATED SHOWERS WITHIN 180 NM EITHER SIDE OF IT N OF
15N. THE MID/UPPER LEVEL LOW IS FORECAST BY THE GFS TO MOVE E TO
JUST E OF THE LEEWARD ISLANDS BY THU NIGHT...WHILE THE SURFACE
TROUGH ALONG 69W...BEGINS TO MOVE WESTWARD TONIGHT AND BECOMES
STATIONARY OVER THE WESTERN CARIBBEAN THU AND FRI. WITH REGARDS
TO THE SURFACE WINDS...NE-E TRADES ARE IN THE RANGE OF 10-20 KT
...WITH EVEN LIGHTER WINDS OF 5-10 KT W OF 80W. NE-E TRADES ARE
FORECAST TO INCREASE OVER THE S CENTRAL AND EASTERN PORTIONS
BEGINNING LATE THU INTO FRI AS CENTRAL ATLC HIGH PRES RIDGING
STRENGTHENS. A WEAKENING STATIONARY FRONT EXTENDS FROM THE
STRAITS OF FLORIDA SW ACROSS THE YUCATAN CHANNEL AND INLAND
ACROSS THE YUCATAN PENINSULA. ONLY ISOLATED SHOWERS ARE NOTED
WITHIN 120 N OF THE FRONT...AND WITHIN 30-60 NM S OF THE
FRONT.

...HISPANIOLA...
ISOLATED SHOWERS AND TSTMS THAT DEVELOPED THIS AFTERNOON OVER
THE INTERIOR PORTION AS WELL AS ALONG THE SOUTHERN COAST OF
HAITI ARE PRESENTLY DISSIPATING...FOR THE MOST PART. SCATTERED
TO BROKEN LOW AND MID LEVEL CLOUDS ARE OBSERVED OVER MUCH OF THE
INTERIOR SECTIONS. HOWEVER...THE ISLANDS REMAINS UNDER DRY
SUBSIDENT CONDITIONS ALOFT INHIBITING THE POTENTIAL FOR THE
DEVELOPMENT OF SCATTERED SHOWERS AND TSTMS EVEN WITH THE BROAD
SURFACE TROUGH JUST TO THE E OF THE ISLAND. MODEL GUIDANCE
SUGGESTS THAT THESE CONDITIONS ALOFT WILL CHANGE VERY LITTLE
THROUGH THE NEXT 48 HOURS ALLOWING FOR LITTLE OVERALL VARIANCES
TO PRESENT OBSERVED CONDITIONS.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHING IS OVER THE N CENTRAL ATLC...AND SUPPORTS
A COLD FRONT THAT EXTENDS FROM 32N61W SW TO 27N74W WHERE IT
BECOMES STATIONARY TO ACROSS THE CENTRAL BAHAMAS AND TO THE
STRAITS OF FLORIDA...CONTINUING TO INLAND THE NE YUCATAN
PENINSULA. PLENTIFUL MOISTURE THROUGH ALL LEVELS OF THE
ATMOSPHERE IS ALLOWING FOR SCATTERED SHOWERS TO CONTINUE TO THE
N OF THE FRONT WHERE A THETA-E GRADIENT EXISTS. THE VERY MOIST
SURFACE NE WIND FLOW AROUND A STRONG 1034 HIGH CENTER OVER THE
EASTERN SEABOARD IS ADVECTING THESE SHOWERS WSW TOWARDS THE
FLORIDA COAST AND KEYS. ISOLATED SHOWERS ARE NOTED TO THE SE OF
THE FRONT.

FURTHER TO THE SE...SATELLITE WATER VAPOR IMAGERY REVEALS A
MID/UPPER LEVEL LOW NEAR 21N65W...ACTING AS A COUPLET WITH THE
EASTERN CARIBBEAN LOW DESCRIBED ABOVE. MID TO UPPER LEVEL
DIFFLUENCE IS OCCURRING TO THE NE OF THE LOW CENTER GENERATING
BROKEN TO SCATTERED MULTILAYERED CLOUDINESS WITH WIDELY
SCATTERED SHOWERS AND TSTMS FROM 10N-32N BETWEEN 55W-63W. THE
NORTHERN EXTENSION OF THE BROAD CARIBBEAN SURFACE TROUGH EXTENDS
ALONG 69W...AND REACHES N TO 26N. ONLY ISOLATED SHOWER AND TSTMS
ARE SEEN WITHIN 360 NM E OF THIS TROUGH. THE TROUGH IS FORECAST TO
MOVE WESTWARD AND EVENTUALLY MERGE WITH THE REMNANTS OF THE
ABOVE MENTIONED STATIONARY FRONT ON THU. THE RESULTANT MERGED
TROUGH WILL THEN TOO MERGE WITH A COLD FRONT EXPECTED TO MOVE
OFF THE FLORIDA PENINSULA...AND EXTEND FROM NEAR 31N69W TO THE
NORTHERN BAHAMAS BY LATE FRI WITH AMPLE LOW LEVEL MOISTURE WITH
SCATTERED SHOWERS FORECAST TO ITS NW. OTHERWISE...THE REMAINDER
OF THE CENTRAL AND EASTERN ATLC REMAINS UNDER THE INFLUENCE OF A
VERY BROAD SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED
NEAR 33N37W. THIS HIGH WILL MOVE SE TO NEAR 28.5N33.5W BY THU
EVENING WHILE WEAKENING SLIGHTLY.

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

$$
AGUIRRE


This weather bulletin was brought to you by:
www.nashvilleweather.net