[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI OCT 26 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...

HURRICANE SANDY IS CENTERED NEAR 27.1N 77.1W AT 26/1800 UTC OR
ABOUT 25 NM NNE OF GREAT ABACO ISLAND AND ABOUT 375 NM SSE OF
CHARLESTON SOUTH CAROLINA MOVING N AT 6 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 971 MB. MAXIMUM SUSTAINED WIND SPEED IS 65
KT WITH GUSTS TO 80 KT. 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. THE LARGE AND STRONG CONVECTIVE BURST
NEAR THE CENTER OF THE STORM HAS MAINLY DISSIPATED...BUT A LARGE
AREA OF ACTIVITY STILL EXISTS. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS N OF THE CENTER FROM 28N-34N BETWEEN
64W-81W. SIMILAR ACTIVITY IS FROM 20N-28N BETWEEN 65W-71W. ONE
OF THE OUTER BANDS ALSO EXTENDS ALL THE WAY INTO THE CARIBBEAN
WHERE SCATTERED MODERATE/STRONG CONVECTION IS FROM 13N-20N
BETWEEN 69W-75W. HISPANIOLA IS EXPERIENCING VERY HEAVY RAINFALL
AT THIS TIME...WHICH COULD CAUSE LIFE-THREATENING FLASH FLOODS
AND MUD SLIDES. THIS IS ESPECIALLY THE CASE IN AREAS OF HIGH
TERRAIN.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 17N42W TO 11N42W MOVING W NEAR 10 KT. THE
WAVE IS EMBEDDED WITHIN A LARGE AREA OF ENHANCED MOISTURE
PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. AN ASCAT PASS FROM
EARLIER THIS MORNING ALSO INDICATES THAT CYCLONIC SURFACE FLOW
IS AROUND THE WAVE AXIS. STRONG WINDS UP TO 25 KT WERE ALSO
OBSERVED IN THE PASS EAST OF THE AXIS. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-13N BETWEEN
34W-38W. ISOLATED MODERATE CONVECTION IS FROM 12N-17N BETWEEN
38W-43W

TROPICAL WAVE IS ALONG 15N49W TO 11N48W MOVING WEST AT 10 KT.
THE WAVE IS EMBEDDED WITHIN THE SAME BROAD AREA OF ENHANCED
MOISTURE THAT THE WAVE TO THE EAST IS WITHIN. IT APPEARS THAT
THE ENERGY FROM THE TWO WAVES MAY BE MERGING...BUT AT THIS TIME
THEY REMAIN SEPARATE. LOW LEVEL CYCLONIC FLOW CAN BE SEEN
DISTINCTIVELY AROUND THIS WAVE...AS WELL AS THE ONE TO THE EAST.
ISOLATED MODERATE CONVECTION IS FROM 11N-16N BETWEEN 48W-51W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE NORTHERN COAST
OF GUINEA AT 11N15W TO 10N19W. THE ITCZ BEGINS AT 10N19W AND
CONTINUES ALONG 7N26W 5N31W 6N37W. ISOLATED MODERATE CONVECTION
IS FROM 3N-8N BETWEEN 23W-29W.

...DISCUSSION...

GULF OF MEXICO...
THE CIRCULATION AROUND HURRICANE SANDY CONTINUES TO BRING WIND
AND RAIN TO FLORIDA AND THE EXTREME SE GULF OF MEXICO. MAINLY
ISOLATED SHOWERS EXTEND DOWN THE EAST COAST OF FLORIDA  AND INTO
THE FLORIDA STRAITS WITH SOME AREAS OF MORE SCATTERED ACTIVITY
WITH HEAVIER RAIN. THE MAJORITY OF THE GULF OF MEXICO IS
EXPERIENCING FAIR CONDITIONS WITH ONLY A FEW LOW-LEVEL ISOLATED
SHOWERS IN THE CENTRAL AND WESTERN GULF. AN UPPER LEVEL TROUGH
EXTENDS INTO THE EASTERN GULF ALONG 86W WITH DRY AIR WRAPPING
AROUND ITS WEST SIDE...WHICH IS HELPING SUPPORT THE FAIR
CONDITIONS. A LONGWAVE UPPER TROUGH COVERING THE CENTRAL CONUS
SUPPORTS A STRONG COLD FRONT THAT HAS BEGUN TO MAKE ITS WAY INTO
THE NW GULF. AS OF 1500 UTC...THE AXIS EXTENDS FROM THE
LOUISIANA/TEXAS BORDER TO SE TEXAS NEAR 27N97W. ONLY A FEW VERY
ISOLATED SHOWERS/THUNDERSTORMS AHEAD OF THE FRONT WITH MORE
ACTIVITY STILL INLAND. WINDS SHOULD BEGIN TO DECREASE ACROSS THE
SE GULF AND SOUTH FLORIDA AS SANDY MOVES NORTH. THE FRONT WILL
CONTINUE TO MOVE QUICKLY THROUGH THE BASIN WITH
SHOWERS/THUNDERSTORMS POSSIBLE ALONG THE AXIS.

CARIBBEAN SEA...
EVEN THOUGH HURRICANE SANDY IS NORTH OF THE CARIBBEAN...THE
WEATHER PATTERN IS STILL BEING DOMINATED BY THE STORM AS BROAD
CYCLONIC FLOW COVERS THE CENTRAL AND WESTERN CARIBBEAN WITH
WINDS UP TO 20 KT STILL PRESENT. AN OUTER RAINBAND IS IMPACTING
THE CENTRAL CARIBBEAN EXTENDING FROM THE SW CARIBBEAN TO
HISPANIOLA. VERY HEAVY RAINFALL IS HITTING HISPANIOLA AND THE
RISK FOR FLOODING AND MUDSLIDES IS HIGH. THE ISLAND WILL LIKELY
CONTINUE TO RECEIVE HEAVY RAIN THROUGHOUT THE DAY. A FEW
ISOLATED SHOWERS ARE ACROSS CUBA AND PUERTO RICO TO EITHER SIDE.
THE REMAINDER OF THE BASIN HAS MOSTLY CLEAR SKIES. TO THE
WEST...DRY AIR ALOFT IS WRAPPING AROUND AN UPPER LEVEL TROUGH IN
THE EASTERN GULF...WHICH IS PROVIDING THE FAIR CONDITIONS ACROSS
THE WESTERN CARIBBEAN. TO THE EAST...DRY AIR IS WRAPPING AROUND
AN UPPER LEVEL RIDGE THAT COVERS THE EASTERN HALF OF THE BASIN
AND EXTENDS IN TO THE CENTRAL ATLC. THIS DRY AIR IS KEEPING THE
FAR EASTERN CARIBBEAN UNDER FAIR CONDITIONS. EXPECT LITTLE
CHANGE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
HURRICANE SANDY CONTINUES TO DOMINATE THE WEST ATLC PRODUCING A
LARGE WIND FIELD AND A LARGE AREA OF SHOWERS/THUNDERSTORMS. SEE
SPECIAL FEATURES ABOVE FOR MORE DETAILS. ALOFT...AN UPPER LEVEL
RIDGE ASSOCIATED WITH THE OUTFLOW OF THE STORM EXTENDS EAST OF
THE BAHAMAS AND INTO THE EASTERN CARIBBEAN COVERING MUCH OF THE
WESTERN AND PORTIONS OF THE CENTRAL ATLC. A BROAD UPPER LEVEL
TROUGH/LOW COVERS THE NORTH CENTRAL ATLC N OF 25N SUPPORTING A
STATIONARY FRONT THAT BARELY SKIRTS THE DISCUSSION AREA ALONG
32N47W 31N53W 31N62W. FARTHER EAST...A WEAK SURFACE TROUGH IS
ALONG 28N41W TO 23N46W. AN UPPER LEVEL JET AROUND THE BASE OF
THE UPPER TROUGH IS PRODUCING A LARGE AREA OF UPPER LEVEL CLOUD
COVER AND POSSIBLE ISOLATED SHOWERS AT THE SURFACE FROM 26N-30N
BETWEEN 34W-60W. A SECOND FRONTAL BOUNDARY EXTENDS FROM A WEAK
1006 MB SURFACE LOW NEAR 32N29W. A COLD FRONT EXTENDS FROM THE
LOW TO 27N32W WHERE IT BECOMES STATIONARY TO 23N37W. SCATTERED
SHOWERS/THUNDERSTORMS EXTEND UP TO 160 NM EAST OF THE AXIS. A
WEAK 1017 MB HIGH COVERS THE FAR EASTERN GULF CENTERED NEAR
25N24W PROVIDING FAIR CONDITIONS ACROSS THIS AREA. HURRICANE
SANDY WILL CONTINUE TO DOMINATE THE WESTERN ATLC FOR THE NEXT
SEVERAL DAYS.

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

$$
WALTON






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