[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 162341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 16 2012

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 GORDON IS CENTERED NEAR 34.2N 52.1W AT 16/2100
UTC OR ABOUT 650 NM ENE OF BERMUDA AND ABOUT 1230 NM W OF THE
AZORES MOVING ENE AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO
65 KT. WIDELY SCATTERED MODERATE CONVECTION IS FROM 33N-36N
BETWEEN 49W-53W. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

TROPICAL WAVE EXTENDS FROM 17N93W TO 22N92W MOVING WNW AT 10 KT.
THE WAVE REMAINS EMBEDDED WITHIN BROAD LOW-LEVEL CYCLONIC FLOW
ACROSS THE YUCATAN PENINSULA AND SW GULF OF MEXICO THIS EVENING.
MUCH OF THE MIDDLE TO UPPER LEVEL FLOW ALOFT OVER THE WAVE
REMAINS DIFFLUENT AND SUPPORTS SCATTERED MODERATE CONVECTION
FROM 18N-22N BETWEEN 88W-94W. ENVIRONMENTAL CONDITIONS REMAIN
FAVORABLE FOR GRADUAL DEVELOPMENT OF THIS SYSTEM TO BECOME A
TROPICAL CYCLONE IN THE NEXT 48 HOURS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 10N31W TO 19N31W MOVING W AT 15-20
KT. THE WAVE REMAINS EMBEDDED WITHIN A LARGE AREA OF ENHANCED
DEEP LAYER MOISTURE AS NOTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY FROM 07N-17N BETWEEN 15W-37W. GLOBAL MODEL DATA SHOWS
THAT THE WAVE COINCIDES WITH A BROAD 700 MB TROUGH AXIS ALONG
31W. DUE TO A LARGE DRY AIRMASS ASSOCIATED WITH A SAHARAN AIR
LAYER...NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE.

TROPICAL WAVE EXTENDS FROM 10N52W TO 17N56W MOVING W AT 20-25
KT. ENERGY FROM THE WAVE CONTINUES TO STRETCH IN A NW-SE
ORIENTATION DUE TO BROAD LOW-LEVEL CYCLONIC FLOW ACROSS THE
CENTRAL TROPICAL ATLC. A MAXIMUM IN 700 MB GLOBAL MODEL WIND IS
NOTED ACROSS THE NORTHERN EXTENT OF THE WAVE AND THIS CONTINUES
TO FUEL A SURGE OF SAHARAN DUST LOCATED E OF 63W TO THE AFRICAN
COAST. SAHARAN DUST IS WRAPPED AROUND THE WAVE RESULTING IN A
LACK OF ANY DEEP CONVECTION AT THIS TIME.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 16N17W TO
10N31W TO 09N42W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 09N42W TO 10N50W. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS FROM 10N-13N BETWEEN 15W-19W. SCATTERED
MODERATE CONVECTION IS FROM 06N-11N BETWEEN 19W-27W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK MIDDLE TO UPPER LEVEL TROUGH IS NOTED OVER THE SE CONUS
AND EXTENDS SOUTHWARD OVER PORTIONS OF THE NORTHERN GULF N OF
28N E OF 90W. THE UPPER LEVEL TROUGH SUPPORTS A STATIONARY FRONT
ANALYZED FROM SOUTH CAROLINA TO SOUTHERN ALABAMA THAT CONTINUES
TO PROVIDE MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE SOUTH OF THE
FRONT ALONG THE GULF COAST RESULTING IN SCATTERED SHOWERS AND
TSTMS N OF 29N E OF 92W. THE TROUGHING THEN STRETCHES SW INTO AN
UPPER LEVEL TROUGH AXIS FROM 27N92W TO 21N99W. MOSTLY DRY AIR IS
FOUND ALOFT NORTH AND WEST OF THIS TROUGH AXIS PROVIDING MUCH OF
THE FAR NW GULF WITH CLEAR SKIES THIS EVENING. HOWEVER SOUTH AND
EAST OF THIS TROUGH AXIS...AN UPPER LEVEL ANTICYCLONIC
CIRCULATION IS CENTERED NEAR 22N88W THAT CONTINUES TO ADVECT
MOISTURE FROM OVER THE SW GULF AND THE TROPICAL WAVE LOCATED
ALONG 93W NORTHWARD TO 26N92W THEN EASTWARD TOWARDS THE FLORIDA
PENINSULA. ISOLATED SHOWERS AND TSTMS ARE OCCURRING FROM 25N-28N
BETWEEN 80W-93W...INCLUDING PORTIONS OF THE FLORIDA PENINSULA.
BENEATH ALL THE MIDDLE TO UPPER LEVEL DYNAMICS GENERATING MOST
OF THE CONVECTION...A SURFACE RIDGE EXTENDS FROM THE SW NORTH
ATLC ALONG 27N AND REMAINS ANCHORED IN THE EASTERN GULF BY A
1019 MB HIGH CENTERED NEAR 28N87W.

CARIBBEAN SEA...
AS MOISTURE ASSOCIATED WITH THE TROPICAL WAVE IN THE SW GULF
OF MEXICO FLEETS WESTWARD THIS EVENING...NORTHEASTERLY FLOW
ALOFT ASSOCIATED WITH AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED NEAR 22N88W CONTINUES TO PROVIDE AN OVERALL STABLE
ATMOSPHERE ACROSS MUCH OF THE WESTERN CARIBBEAN W OF 80W. A FEW
ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER PORTIONS OF CUBA
DUE TO PEAK DAYTIME HEATING AND INSTABILITY...HOWEVER THESE ARE
EXPECTED TO DIMINISH WITH SUNSET. MOST OF THE CONVECTIVE
ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ALONG 93W IS WELL
INLAND ACROSS CENTRAL AMERICA WITH THE POTENTIAL FOR LOCALIZED
HEAVY RAINFALL AND FLOODING THROUGH THE OVERNIGHT HOURS. FARTHER
EAST...AN INVERTED UPPER LEVEL TROUGH COVERS THE REMAINDER OF
THE CARIBBEAN E OF 75W WITH AXIS EXTENDING FROM AN UPPER LEVEL
LOW IN THE ATLC NEAR 27N64W TO 20N67W TO 12N72W. SCATTERED
SHOWERS AND TSTMS ARE OCCURRING EAST OF THE TROUGH AXIS ACROSS
PORTIONS OF PUERTO RICO...HISPANIOLA...AND JAMAICA AND THESE ARE
MOST LIKELY THE RESULT OF PEAK DAYTIME HEATING AND INSTABILITY.
A SURGE OF SAHARAN DUST IS BEGINNING TO MOVE ITS WAY INTO THE
EASTERN CARIBBEAN...CURRENTLY E OF 63W...HOWEVER THE APPROACH OF
A TROPICAL WAVE ALONG 54W WILL PROVIDE FOR ISOLATED SHOWERS WELL
INTO THE WEEKEND PERIOD.

ATLANTIC OCEAN...
UPPER LEVEL DIFFLUENCE IS MAXIMIZED ACROSS THE SW NORTH ATLC
THIS EVENING AS AN UPPER LEVEL RIDGE EXTENDS FROM 22N88W NE TO
30N71W. WITH AN OVERALL WEAK PRESSURE GRADIENT AT THE SURFACE...
ISOLATED SHOWERS AND TSTMS ARE OCCURRING N OF 24N W OF 70W.
NORTHEAST OF THIS AREA...A WEAK SURFACE TROUGH IS ANALYZED FROM
BERMUDA NEAR 32N65W TO 28N72W AND ALONG WITH AN UPPER LEVEL LOW
CENTERED NEAR 27N64W CONTINUES TO PROVIDE FOCUS FOR ISOLATED
SHOWERS AND TSTMS N OF 24N BETWEEN 60W-70W. THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 28N43W. TROPICAL
STORM GORDON TRACKS NORTH OF THIS SURFACE RIDGE...WHILE THE
TROPICAL WAVES MOVING WESTWARD IN THE TROPICAL ATLC REMAIN
LARGELY S OF 20N AND SHROUDED IN SAHARAN DUST SOUTH OF THE RIDGE.

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

$$
HUFFMAN



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