[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU NOV 21 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
2315 UTC.

...SPECIAL FEATURES...
TROPICAL STORM MELISSA IS CENTERED NEAR 40.9N 32.1W AT 21/2100
UTC OR ABOUT 295 NM NW OF THE AZORES MOVING ENE AT 24 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 980 MB. MAXIMUM SUSTAINED
WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. ISOLATED MODERATE
CONVECTION IS FROM 39N-42N BETWEEN 27W-33W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N12W TO
03N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
03N19W TO 03N21W TO 06N28W TO 05N32W TO 07N43W. SCATTERED
MODERATE CONVECTION IS FROM 01N-08N BETWEEN 23W-36W.

...DISCUSSION...

GULF OF MEXICO...
SOUTHWESTERLY FLOW ALOFT DOMINATES OVER THE GULF THIS EVENING
WITH WATER VAPOR IMAGERY INDICATING MODERATELY MOIST MIDDLE TO
UPPER LEVELS WITH MOST CLOUDINESS REMAINING ACROSS THE
NORTHEASTERN ONE-THIRD OF THE GULF...INCLUDING MUCH OF THE
FLORIDA PENINSULA. OTHERWISE...A SURFACE RIDGE ANCHORED WELL TO
THE NE ACROSS THE NEW ENGLAND STATES EXTENDS SW THROUGH THE SE
CONUS INTO THE SW GULF PROVIDING E-SE WINDS GENERALLY IN THE
RANGE OF 10 TO 15 KT. WHILE THE SURFACE RIDGING IS KEEPING
CONDITIONS FAIRLY TRANQUIL...THE ONLY SHOWERS NOTED ARE
OCCURRING N OF 26N E OF 89W...WITH EARLY EVENING SEABREEZE
SHOWERS AND TSTMS OCCURRING ACROSS THE FLORIDA PENINSULA.
EASTERLY FLOW IS EXPECTED TO PERSIST THROUGH LATE FRIDAY WHEN
THE NEXT COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS AND
LOUISIANA COASTS LATE FRIDAY INTO EARLY SATURDAY WITH N-NE WINDS
SPREADING ACROSS THE BASIN THROUGH THE UPCOMING WEEKEND.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE SOUTH-CENTRAL
CARIBBEAN NEAR 12N74W AND IS PROVIDING MUCH OF THE BASIN W OF
75W WITH SOUTHWESTERLY FLOW ALOFT. OVERALL...WATER VAPOR IMAGERY
INDICATES THIS SW FLOW REMAINS RELATIVELY DRY...RESULTING IN
MOSTLY CLEAR SKIES AND FAIR CONDITIONS ACROSS THE WESTERN
CARIBBEAN. HOWEVER...A SURFACE TROUGH ANALYZED FROM 10N79W TO
17N80W IS PROVIDING WEAK LOW-LEVEL MOISTURE CONVERGENCE
PRODUCING LOW-TOPPED ISOLATED SHOWERS AND TSTMS FROM 15N-19N
BETWEEN 75W-84W. FARTHER EAST...DRIER CONDITIONS ALOFT PREVAIL
WITH NORTHWESTERLY FLOW NOTED ON WATER VAPOR IMAGERY BETWEEN 75W
AND A BROAD UPPER LEVEL TROUGH AXIS ALONG 64W. TRANQUIL
CONDITIONS ONCE AGAIN PERSIST UNDERNEATH THE STABLE ENVIRONMENT
WITH ONLY A FEW AREAS OF ISOLATED LOW-TOPPED SHOWERS OCCURRING
ACROSS THE FAR NE AND FAR SE CORNERS OF THE BASIN. LASTLY...
TRADES ARE FORECAST TO REMAIN 20 KT OR LESS THROUGH THE
REMAINDER OF THE WEEK INTO THE UPCOMING WEEKEND.

...HISPANIOLA...
CURRENTLY SKIES REMAIN MOSTLY CLEAR THIS EVENING AS OVERALL
TRANQUIL CONDITIONS PREVAIL. WATER VAPOR IMAGERY INDICATES DRY
AND STABLE NORTHWESTERLY FLOW ALOFT IS IN POSITION TO STAY FOR
THE NEXT FEW DAYS PROVIDING CONTINUED FAIR SKIES.

ATLANTIC OCEAN...
A MID-LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY IN
THE VICINITY OF 31N63W THAT IS PARTIALLY SUPPORTING A COLD FRONT
ANALYZED FROM 32N45W SW TO 27N58W THEN WEST TO 27N65W WHERE IT
BECOMES STATIONARY TO THE BAHAMAS NEAR 26N78W. THE WESTERN
EXTENT OF THE FRONT IS GRADUALLY BECOMING A SHEAR LINE DUE TO
STRONGER NE WINDS NOTED ON EARLIER SCATTEROMETER PASSES TO THE
NORTH OF THE AXIS ACROSS THE REGION. ISOLATED SHOWERS AND TSTMS
ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT...AND FROM
25N-29N BETWEEN 77W-82W...INCLUDING THE COASTAL WATERS OFF THE
FLORIDA PENINSULA AND INLAND PORTIONS AS WELL. TO THE EAST...A
PRE-FRONTAL SURFACE TROUGH IS ANALYZED TO THE SE OF THE COLD
FRONT FROM 24N46W TO 32N38W AND IS PROVIDING FOCUS FOR ISOLATED
SHOWERS AND TSTMS EAST OF THE AXIS WITHIN 240 NM EITHER SIDE OF
A LINE FROM 17N46W TO 30N33W. THIS CLOUDINESS AND PRECIPITATION
IS LIKELY ENHANCED DUE TO A WEAK UPPER LEVEL TROUGH AXIS ALIGNED
FROM 25N45W SW TO A BROAD BASE OVER THE SW CARIBBEAN SEA. ACROSS
THE EASTERN ATLC...A VIGOROUS MIDDLE TO UPPER LEVEL LOW IS
CENTERED OFF THE COAST OF WEST AFRICA NEAR 16N23W THAT CONTINUES
TO ADVECT MOISTURE FROM THE DEEP TROPICS NORTHWARD TO 22N IN A
ZONE BETWEEN 10W-25W. ISOLATED SHOWERS AND TSTMS ARE POSSIBLE IN
THE AREA COVERING 07N-22N BETWEEN 13W-24W...INCLUDING PORTIONS
OF THE CAPE VERDE ISLANDS AND COASTAL WEST AFRICA. OTHERWISE...A
SURFACE RIDGE TO THE NORTH ANCHORED BY A 1020 MB HIGH CENTERED
NEAR 29N26W IS PROVIDING FAIR CONDITIONS FOR AREAS N OF 22N E OF
32W.

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

$$
HUFFMAN


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