[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI SEP 07 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 MICHAEL IS CENTERED NEAR 31.2N 41.1W AT 07/1500 UTC OR
ABOUT 810 NM WSW OF THE AZORES MOVING NW AT 03 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 970 MB. MAXIMUM SUSTAINED WIND SPEED
IS 90 KT WITH GUSTS TO 110 KT. SCATTERED MODERATE CONVECTION IS
FROM 29N-33N BETWEEN 39W-43W. SEE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

TROPICAL STORM LESLIE IS CENTERED NEAR 27.1N 62.2W AT 07/1800
UTC OR ABOUT 340 NM SSE OF BERMUDA MOVING N AT 04 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 982 MB. MAXIMUM SUSTAINED WIND SPEED
IS 55 KT WITH GUSTS TO 65 KT. SCATTERED MODERATE CONVECTION IS
FROM 24N-32N BETWEEN 58W-64W. SEE LATEST NHC INTERMEDIATE PUBLIC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 AND
THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/
WTNT22 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 12N16W TO 20N17W MOVING W AT 10-15
KT. A 1012 MB LOW IS CENTERED AT THE SOUTHERN EXTENT OF THE WAVE
AXIS NEAR 13N16W AND IS FORECAST TO EMERGE OFF THE W AFRICA
COAST DURING THE NEXT 24 TO 36 HOURS. MANY OF THE GLOBAL MODELS
SUGGEST AT A MINIMUM A BROAD LOW-LEVEL CYCLONIC CIRCULATION
LOCATING SE OF THE CAPE VERDE ISLANDS IN THE VICINITY OF 14N22W.
THE WAVE AXIS ITSELF IS HIGHLY EVIDENT IN TOTAL PRECIPITABLE
WATER AND SATELLITE IMAGERY WITH SCATTERED MODERATE CONVECTION
OCCURRING FROM 07N-14N BETWEEN 17W-22W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO
A 1014 MB MONSOONAL LOW NEAR 16N28W TO 10N45W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 10N45W TO 06N56W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 17N-20N BETWEEN 28W-32W
LOCATED NORTH OF THE MONSOONAL LOW NEAR 16N28W.

...DISCUSSION...

GULF OF MEXICO...
MOSTLY NORTHEASTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY
ACROSS MUCH OF THE GULF THIS AFTERNOON ON THE EASTERN PERIPHERY
OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER CENTRAL
TEXAS NEAR 31N99W. EMBEDDED WITHIN THE NE FLOW ALOFT OVER THE
CENTRAL GULF IS A 1009 MB LOW CENTERED NEAR 28N89W. SURFACE
TROUGHING EXTENDS SW FROM THE LOW CENTERED TO 25N92W. SATELLITE
IMAGERY AND LIGHTNING DATA INDICATE SCATTERED SHOWERS AND
ISOLATED TSTMS WITHIN THE SOUTHERN SEMICIRCLE OF THE LOW
OCCURRING FROM 23N-27N BETWEEN 87W-93W. ISOLATED SHOWERS ARE
ALSO NOTED TO THE EAST OF THE LOW OVER THE EASTERN GULF WATERS
EMBEDDED WITHIN MOIST AND UNSTABLE LOW-LEVEL MOISTURE N OF
24N...INCLUDING PORTIONS OF THE WESTERN FLORIDA PENINSULA COAST.
THE LOW IS FORECAST TO LINGER OVER THE NORTH-CENTRAL AND NE GULF
THROUGH LATE SATURDAY AND BECOME ABSORBED BY A FRONTAL BOUNDARY
SWEEPING ACROSS THE NORTHERN GULF SUNDAY AND ACROSS NORTH AND
CENTRAL FLORIDA LATE SUNDAY INTO MONDAY. OTHERWISE...THE
REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A WEAK SURFACE
RIDGE EXTENDING FROM THE SW NORTH ATLC INTO THE SE GULF...THEN
WESTWARD ALONG 23N TO EAST-CENTRAL MEXICO NEAR 22N98W. OUTSIDE
OF THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE LOW...FAIR
CONDITIONS AND MOSTLY CLEAR SKIES PREVAIL THIS AFTERNOON.

CARIBBEAN SEA...
AN ELONGATED UPPER LEVEL TROUGH AXIS EXTENDS FROM THE SW NORTH
ATLC NEAR 32N72W TO WESTERN CUBA AND INTO THE NW CARIBBEAN WITH
A BASE NEAR 17N87W. MOSTLY DRY AIR IS NOTED ON WATER VAPOR
IMAGERY WITH THIS TROUGHING AS GENERALLY E TO SE WINDS OF 10 TO
15 KT ARE OBSERVED W OF 80W. LOW-LEVEL MOISTURE CONVERGENCE IS
MAXIMIZED OVER THE SW CARIBBEAN AS SCATTERED SHOWERS AND TSTMS
ARE OCCURRING S OF 13N BETWEEN 79W-84W. THE REMAINDER OF THE
CARIBBEAN BASIN E OF 80W IS UNDER MOSTLY DRY AIR ALOFT AND
GENERALLY 10 TO 15 KT TRADEWINDS. NE TO E WINDS ARE HOWEVER A
BIT STRONGER...IN THE RANGE OF 15 TO 20 KT...PER AN EARLIER
ASCAT AND WINDSAT PASS S OF 15N BETWEEN 70W-80W. CLEAR SKIES
DOMINATE ELSEWHERE THIS AFTERNOON AND CONDITIONS REMAIN
TRANQUIL. THE E TO SE MODERATE TO FRESH TRADEWINDS ARE FORECAST
TO PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS OVER THE SW NORTH ATLC WATERS
FROM 32N72W TO WESTERN CUBA NEAR 22N80W. WHILE A WEAK SURFACE
RIDGE AXIS EXTENDS FROM WEST OF BERMUDA NEAR 32N70W TO A 1016 MB
HIGH CENTERED NEAR 27N76W...THE MIDDLE TO UPPER LEVEL DYNAMICS
REMAIN STRONG ENOUGH TO SUPPORT ISOLATED SHOWERS AND TSTMS FROM
27N-32N BETWEEN 75W-79W. FARTHER EAST...THE RATHER LARGE EXTENT
OF TROPICAL STORM LESLIE REMAINS N OF 20N BETWEEN 53W-68W. SE OF
LESLIE...A WEAK SURFACE RIDGE EXTENDS FROM 27N33W TO THE LESSER
ANTILLES NEAR 14N61W ANCHORED BY A 1018 MB HIGH CENTERED NEAR
22N43W. FINALLY...AS HURRICANE MICHAEL HEADS FOR THE NORTHERN
BORDER OF THE DISCUSSION AREA BETWEEN 37W-44W...THE REMAINDER OF
THE EASTERN ATLC N OF 20N IS UNDER THE INFLUENCE OF SURFACE
RIDGING ANCHORED BY A PAIR OF 1022 MB HIGHS CENTERED NEAR 33N14W
AND 36N26W.

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

$$
HUFFMAN




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