[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE OCT 23 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM SANDY IS CENTERED NEAR 14.1N 77.6W AT 23/1800 UTC
OR ABOUT 240 NM SSW OF KINGSTON JAMAICA MOVING NNE AT 4 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM SUSTAINED
MAXIMUM WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION IS FROM 09N-17W BETWEEN
69W-83W. WIDELY SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM
09N-20N BETWEEN 68W-83W. SEE LATEST NHC INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC AND THE
FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23
KNHC FOR MORE DETAILS.

TROPICAL DEPRESSION NINETEEN IS CENTERED NEAR 25.7N 51.0W AT
23/1500 UTC OR ABOUT 795 NM NE OF THE LEEWARD ISLANDS MOVING NNE
AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM
SUSTAINED MAXIMUM WIND SPEED IS 30 KT WITH GUSTS TO 40 KT.
SCATTERED MODERATE CONVECTION IS FROM 23N-28N BETWEEN 47W-52W.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 08N29W TO 16N29W MOVING W AT 10-15
KT. THE WAVE REMAINS LARGELY EMBEDDED WITHIN THE MONSOON TROUGH
AS A 1011 MB LOW IS CENTERED AT THE SOUTHERN EXTENT OF THE WAVE
AXIS. BROAD LOW-LEVEL CYCLONIC FLOW IS NOTED IN GLOBAL MODEL
STREAMLINE ANALYSIS BETWEEN 25W-33W WITH SCATTERED MODERATE
CONVECTION CONFINED TO THE SOUTHWESTERN QUADRANT OF THE LOW
OCCURRING FROM 04N-08N BETWEEN 29W-33W.

TROPICAL WAVE EXTENDS FROM 09N39W TO 16N39W MOVING W AT 5-10 KT.
THE WAVE REMAINS EMBEDDED WITHIN THE MONSOON TROUGH WITH BROAD
LOW-LEVEL CYCLONIC TURNING OF THE LOW-LEVEL CLOUD FIELD BETWEEN
34W-42W. ISOLATED MODERATE CONVECTION IS FROM 07N-10N BETWEEN
35W-37W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
09N19W TO 08N29W TO 10N36W TO 08N40W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 08N40W TO 09N50W TO 08N54W.
SCATTERED MODERATE CONVECTION IS FROM 12N-14N BETWEEN 16W-21W.
ISOLATED MODERATE CONVECTION IS FROM 03N-09N BETWEEN 12W-24W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL RIDGE IS OVER THE GULF WITH AXIS
EXTENDING FROM WEST-CENTRAL MEXICO NEAR 22N104W TO BEYOND
NORTHERN GEORGIA NEAR 34N85W. NORTHWESTERLY WINDS ALOFT DOMINATE
OVER THE GULF AS WATER VAPOR IMAGERY INDICATES A VERY DRY AND
STABLE AIRMASS IS PROVIDING CLEAR SKIES AND FAIR WEATHER THIS
AFTERNOON. A SURFACE RIDGE FURTHER SUPPORTS THE FAIR WEATHER
ANCHORED BY A 1023 MB HIGH CENTERED OVER NORTH CAROLINA NEAR
35N79W. THE RIDGE IS FORECAST TO REMAIN ACROSS THE GULF THROUGH
THURSDAY WITH MOSTLY EAST-SOUTHEASTERLY WINDS EXPECTED OVER THE
NEXT 24 TO 36 HOURS. THEREAFTER THE TRACK OF TROPICAL STORM
SANDY WILL TRACK INTO THE SW NORTH ATLC AND PROVIDE THE GULF AND
FLORIDA PENINSULA WITH MOSTLY NORTHEASTERLY WINDS ON THE SE
PERIPHERY OF THE RIDGE AXIS.

CARIBBEAN SEA...
THE BROAD CIRCULATION OF TROPICAL STORM SANDY REMAINS THE FOCUS
FOR THE CARIBBEAN THIS AFTERNOON WITH NUMEROUS SHOWERS AND
SCATTERED STRONG TSTMS OCCURRING OVER A LARGE AREA FROM 09N-20N
BETWEEN 69W-84W. WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL
TROUGH AXIS EXTENDS ALONG 82W AND DIPS SOUTHWARD TO A BASE NEAR
17N81W. THIS TROUGH IS EXPECTED TO HELP GUIDE SANDY ON A
NORTHWARD TRACK THROUGH FRIDAY MORNING. THE PRIMARY IMPACTS WILL
REMAIN AN OVERALL LARGE CYCLONIC WIND FIELD AND THE INCREASED
PROBABILITY OF HEAVY RAINFALL OVER JAMAICA...EASTERN CUBA...AND
HISPANIOLA. THIS WILL RESULT IN THE POSSIBILITY OF LIFE-
THREATENING FLASH FLOODS AND MUD SLIDES...ESPECIALLY IN AREAS OF
HIGHER TERRAIN. STORM SURGE WILL ALSO REMAIN A KEY IMPACT FOR
THE SOUTHERN AND EASTERN COASTS OF JAMAICA AS THE SURGE WILL BE
ACCOMPANIED BY LARGE AND DESTRUCTIVE WAVES.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ACROSS THE WESTERN ATLC
N OF 30N BETWEEN 42W-65W THAT SUPPORTS A DISSIPATING COLD FRONT
ANALYZED INTO THE DISCUSSION AREA NEAR 32N53W. THE COLD FRONT
EXTENDS SW TO 27N60W AND BECOMES A SHEAR LINE ALONG 24N70W TO
WESTERN CUBA NEAR 23N79W. SCATTERED SHOWERS AND ISOLATED TSTMS
ARE OCCURRING ALONG AND SOUTH OF THE SHEAR LINE FROM 20N-27N
BETWEEN 65W-80W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM
EITHER SIDE OF THE DISSIPATING COLD FRONT. THE COLD FRONT IS
FORECAST TO CONTINUE DRIFTING E-NE OVER THE NEXT 24 TO 36 HOURS
WHILE THE SHEAR LINE BECOMES ABSORBED BY THE APPROACHING
TROPICAL STORM SANDY BEYOND THURSDAY. A SURFACE RIDGE IS
ANCHORED BY A 1023 MB HIGH CURRENTLY CENTERED OVER NORTH
CAROLINA NEAR 35N79W AND IS FORECAST TO REMAIN NEARLY STATIONARY
THROUGH WEDNESDAY UNTIL SANDY TRACKS INTO SOUTHERN PORTIONS OF
THE SW NORTH ATLC WATERS. ELSEWHERE OVER THE CENTRAL ATLC...
TROPICAL DEPRESSION NINETEEN CONTINUES TO IMPACT A RELATIVELY
SMALL AREA FROM 20N-29N BETWEEN 46W-55W AND IS FORECAST TO
BECOME ABSORBED INTO THE PREVIOUSLY MENTIONED FRONTAL BOUNDARY
APPROXIMATELY 360 NM TO ITS NORTHWEST. FINALLY...A SET OF 1017
MB HIGHS ARE CENTERED NEAR 23N26W...29N39W...AND 32N40W OVER
NORTHEASTERN PORTIONS OF THE ATLC DISCUSSION AREA. A WEAK
SURFACE TROUGH IS ANALYZED ON THE SOUTHWESTERN PERIPHERY OF THE
RIDGING FROM 20N39W TO 24N34W WITH POSSIBLE ISOLATED SHOWERS
OCCURRING FROM 19N-25N BETWEEN 30W-40W.

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

$$
HUFFMAN




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