[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI DEC 04 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.

...ITCZ/MONSOON TROUGH...
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 02N AND THE
PRIME MERIDIAN TO 05N09W TO 05N18W TO 05N29W TO 04N37W TO 01N45W.
WIDELY SCATTERED MODERATE CONVECTION IS SEEN WITHIN 120 NM S OF
THE AXIS BETWEEN 06W-15W..AND N OF THE AXIS WITHIN 30 NM OF LINE
FROM 07N33W TO 07N36W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL SOUTHWESTERLY FLOW ALOFT COUPLED WITH MID-LEVEL
ENERGY ASSOCIATED WITH A SHORTWAVE TROUGH AXIS EXTENDING OVER
THE FLORIDA PANHANDLE SW TO OVER EAST-CENTRAL MEXICO AS OF
04/1500 UTC SUPPORTS A STATIONARY FRONT MEANDERING FROM ACROSS
THE FAR SOUTHERN FLORIDA PENINSULA TO JUST N OF THE NORTHERN
YUCATAN PENINSULA NEAR 22N88W...AND SW FROM THERE AS A
DISSIPATING STATIONARY FRONT TO INLAND THE CENTRAL YUCATAN
PENINSULA. A CARIBBEAN SURFACE TROUGH STRETCHES FROM A 1017 MB
LOW NEAR 19N87W NE TO JUST W OF THE WESTERN TIP OF CUBA...AND TO
THE WESTERN PART OF THE STRAITS OF FLORIDA. THE COMBINATION OF
THE FRONT SERVING AS A FOCUSING MECHANISM FOR SURFACE
CONVERGENCE ALONG WITH DEEP MID AND UPPER LEVEL MOISTURE IN SW
FLOW IS BRINGING AREAS OF RAIN WITH EMBEDDED SCATTERED TO
NUMEROUS SHOWERS AND TSTMS ARE CONFINED TO THE FAR SE PORTION OF
THE GULF S OF THE FRONT BETWEEN THE MID-LEVEL TROUGH AXIS AND
THE FRONTAL BOUNDARY TO ITS SE. MOST MIDDLE TO UPPER LEVEL CLEARING
IS NOTED ON WATER VAPOR IMAGERY ACROSS THE REMAINDER OF THE GULF
EARLY THIS AFTERNOON. MAINLY FRESH TO STRONG N-NE WINDS
PREVAIL TO NW OF THE FRONTAL BOUNDARY WITH LIGHTER WINDS...IN
MODERATE BREEZE RANGE...ACROSS THE NW GULF ALONG THE TEXAS
COAST. THE FRONT WILL BE SLOW TO SLIDE GRADUALLY EASTWARD
THROUGH SATURDAY EXTENDING FROM THE STRAITS OF FLORIDA TO THE
YUCATAN PENINSULA. RIDGING IS EXPECTED TO REMAIN IN PLACE WITH
AXIS ALONG THE TEXAS AND EASTERN MEXICO COAST THROUGH MONDAY.

CARIBBEAN SEA...
UPPER LEVEL RIDGING IS NOTED ON WATER VAPOR IMAGERY OVER THE
WESTERN CARIBBEAN WITH AXIS ANCHORED NEAR 12N82W EXTENDING N-NE
TO BEYOND CENTRAL CUBA NEAR 25N76W. UPPER LEVEL DIFFLUENCE
ASSOCIATED WITH THE RIDGING ALOFT IN TANDEM WITH A WEAK 1017 MB
SURFACE LOW AT 19N87W WITH ASSOCIATED TROUGH NE TO NEAR WESTERN
CUBA AND THE WESTERN STRAITS OF FLORIDA CONTINUES AS OF 04/1500
UTC CONTINUES TO PROVIDE THE FOCUS FOR SCATTERED SHOWERS AND
TSTMS ACROSS THE NW CARIBBEAN N OF 15N BETWEEN 81W-88W. THIS
AREA HAS EXPERIENCED PERSISTENT SURFACE TROUGHING ACROSS THE NW
CARIBBEAN DURING THE PAST SEVERAL DAYS AS A FRONTAL BOUNDARY
CONTINUES TO DRIFT ACROSS THE SE GULF OF MEXICO. ELSEWHERE...AN
UPPER LEVEL LOW IS CENTERED NEAR 20N69W WITH A RELATED
TROUGH EXTENDING SSW TO 15N71W TO 13N71W. MIDDLE TO UPPER LEVEL
MOISTURE ADVECTION OCCURRING ON SOUTHWESTERLY WINDS E OF THE TROUGH
AXIS ALONG 72W. SCATTERED SHOWERS AND ISOLATED TSTMS NOTED E OF THE
TROUGH FROM 11N-17N. WITH THE DEEP MOISTURE IN PLACE E OF THE
TROUGH CHANGING LITTLE THROUGH THE NEXT 48 HOURS...AND COMBINING
WITH THE PREVAILING TRADES EXPECT THE SHOWER AND TSTM ACTIVITY TO LAST
THROUGH THE NEXT 48 HOURS. OTHERWISE...FRESH TO STRONG TRADES
PREVAIL ACROSS MOST OF THE BASIN EXCEPT W OF 82W WHERE THE SURFACE
TROUGH AXIS IS GENERATING BROAD GENTLE CYCLONIC FLOW.

...HISPANIOLA...
THE AFOREMENTIONED UPPER LEVEL LOW JUST N OF THE ISLAND NEAR 20N69W
CONTINUES TO AMPLE LOW-LEVEL MOISTURE WITH POSSIBLE ISOLATED SHOWERS
ACROSS MAINLY THE N CENTRAL AND EASTERN PARTS OF THE ISLAND. MODEL
GUIDANCE SUGGESTS THAT THE UPPER LOW WILL SLOWLY DRIFT EASTWARD AND
WEAKEN TO A TROUGH BY SUN EVENING AS UPPER LEVEL RIDGING SETTLES IN
WITH A DRYING TREND IN ITS WAKE.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHING EXTENDS FROM OVER THE CANADIAN MARITIMES
SW TO OVER THE MID-ATLC REGION WITH SHORTWAVE TROUGHING PREVAILING
OVER THE CAROLINAS SW TO THE CENTRAL GULF OF MEXICO. AS 04/1500 UTC
THE TROUGHING SUPPORTS A COLD FRONT ANALYZED FROM NEAR 32N63W SW TO
A WEAK 1017 MB LOW AT 27N79W...THEN STRADDLES THE SE FLORIDA COAST
AND SW TO JUST N OF THE FLORIDA KEYS. A JET STREAM BRANCH STRETCHES
FROM THE SW GULF OF MEXICO NE TO ACROSS S FLORIDA...AND NE TO N OF
THE AREA NEAR 32N65W. RIPPLES OF SHORTWAVE ALONG THE JET STREAM FLOWING
NE IN THE VICINITY OF THE FRONT ARE RESULTING IN WIDESPREAD AREAS OF
RAIN WITH EMBEDDED SCATTERED SHOWERS AND TSTMS OBSERVED FROM 25N-30N
BETWEEN 71W-77W...AND ALSO S OF 32N W OF 77W TO JUST SE OF THE S FLORIDA
COAST. SIMILAR ACTIVITY WITH POSSIBLE GUSTY WINDS IS VERY ACTIVE ACROSS
THE STRAITS OF FLORIDA EARLY THIS AFTERNOON. THE INTERACTION BETWEEN
THE FRONT AND STRONG HIGH PRESSURE TO ITS N WILL BRING FRESH TO STRONG
NE-E WINDS OVER THE WATERS TO THE N OF THE FRONT INTO SUN BEFORE
DIMINISHING. THE COLD FRONT PORTION OF THE BOUNDARY WILL REACH
FROM NEAR 32N65W TO NEAR 28N73W BY SUN EVENING. OTHERWISE...SURFACE HIGH
PRESSURE PREVAILS ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN ATLC
ANCHORED BY A 1037 MB HIGH CENTERED NE OF THE AZORES NEAR 42N19W.

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

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AGUIRRE
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