[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 25 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION MATTHEW IS CENTERED NEAR 16.7N 88.6W AT
25/1800 UTC OR ABOUT 52 NM SSW OF BELIZE CITY MOVING WNW AT 13
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM
SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST
NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.
RAINFALL ASSOCIATED WITH MATTHEW CONTINUES TO BE THE MAIN THREAT
TO CENTRAL AMERICA AND IS LIKELY TO CONTINUE EVEN AFTER MATTHEW
HAS DISSIPATED. TOTAL RAIN ACCUMULATIONS OF 6 TO 10 INCHES OVER
PORTIONS OF HONDURAS...GUATEMALA...BELIZE AND ISOLATED MAXIMUM
AMOUNTS OF UP TO 15 INCHES ARE POSSIBLE OVER THE NEXT COUPLE OF
DAYS. THESE RAINS COULD PRODUCE LIFE THREATENING FLASH FLOODS
AND MUD SLIDES. CURRENTLY...NUMEROUS STRONG CONVECTION IS OVER
GUATEMALA FROM 15N-17N BETWEEN 88W-92W...WITH NUMEROUS
MODERATE/SCATTERED STRONG CONVECTION FROM 11N-19N BETWEEN
88W-94W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS ALSO E
OF THE SYSTEM FROM 7N-21N BETWEEN 81W-87W.

TROPICAL STORM LISA IS CENTERED NEAR 22.7N 28.2W AT 25/1500 UTC
OR ABOUT 470 NM NNW OF THE CAPE VERDE ISLANDS MOVING N AT 10 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 990 MB. MAXIMUM SUSTAINED
WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS. LISA REMAINS SMALL WITH SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 21N-24N BETWEEN
26W-30W...AND FROM 25N-27N BETWEEN 27W-30W. LISA IS ALREADY
EXPERIENCING UPPER LEVEL WLY SHEAR WHICH IS FORECAST TO
CONTINUE...AND WILL FURTHER WEAKEN LISA OVER THE NEXT SEVERAL
DAYS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N12W 6N21W 3N32W 6N45W 7N52W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM
EITHER SIDE OF THE AXIS BETWEEN 14W-35W.

...DISCUSSION...

GULF OF MEXICO...
MAINLY ELY SURFACE FLOW OF 10-15 KT COVERS MUCH OF THE GULF OF
MEXICO WITH SOME CYCLONIC FLOW AROUND A WEAK SURFACE TROUGH
EXTENDING FROM THE FLORIDA PANHANDLE NEAR 31N84W INTO THE
CENTRAL GULF TO NEAR 23N91W. THE TROUGH IS SUPPORTED BY A
SHORTWAVE UPPER TROUGH EXTENDING FROM THE FLORIDA BIG BEND TO
NEAR 25N94W. UPPER DIFFLUENCE AROUND THE TROUGH ALONG WITH
SIGNIFICANT MOISTURE ACROSS THE AREA IS ENHANCING SCATTERED
SHOWERS/THUNDERSTORMS FROM 25N-30N BETWEEN 83W-92W. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO OFF THE TEXAN COAST FROM 26N-29N
BETWEEN 91W-97W...AND WITHIN 120 NM OF THE ERN MEXICAN COAST.
ELSEWHERE ALOFT...MAINLY ANTI-CYCLONIC FLOW IS ACROSS THE BASIN
CENTERED OVER CENTRAL MEXICO NEAR 22N98W. EXPECT
SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS MUCH OF THE BASIN AS
MOISTURE ASSOCIATED WITH T.S. MATTHEW PUSHES NWD...AND A FRONTAL
BOUNDARY AND ASSOCIATED LONGWAVE UPPER TROUGH CURRENTLY OVER THE
ERN CONUS DIPS S.

CARIBBEAN SEA...
T.S. MATTHEW CONTINUES TO IMPACT MUCH OF CENTRAL AMERICA
BRINGING STRONG SHOWERS/ISOLATED THUNDERSTORMS S OF 21N W OF
80W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. ALOFT...UPPER
LEVEL RIDGING IS ACROSS THE NW CARIBBEAN AROUND AN UPPER LEVEL
ANTI-CYCLONE CENTERED OVER CENTRAL MEXICO. AN UPPER LEVEL TROUGH
IS ACROSS GUATEMALA ASSOCIATED WITH MATTHEW. A SECOND UPPER
LEVEL TROUGH IS ACROSS THE CENTRAL CARIBBEAN CENTERED OVER HAITI
PRODUCING SCATTERED SHOWERS/THUNDERSTORMS FROM N OF COLOMBIA TO
20N BETWEEN 67W-78W. FARTHER E...A WEAK UPPER LEVEL TROUGH
ACROSS THE LESSER ANTILLES IS SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS S OF 13N BETWEEN 61W-65W...AND FROM
15N-16N BETWEEN 58W-62W. EXPECT CONTINUED SHOWER ACTIVITY ACROSS
MUCH OF THE BASIN OVER THE NEXT SEVERAL DAYS.

ATLANTIC OCEAN...
SURFACE RIDGING AROUND A 1022 MB BERMUDA HIGH CENTERED NEAR
34N59W DOMINATES THE SW ATLC. A FEW ISOLATED SHOWERS ARE ACROSS
THE FLORIDA PENINSULA...AND N OF HISPANIOLA AROUND AN UPPER
LEVEL LOW CENTERED OF HAITI. A WEAK 1013 MB LOW IS CENTERED NEAR
30N48W SUPPORTING A FEW ISOLATED SHOWERS WITHIN 60 NM OF THE
CENTER. A SECOND 1011 MB LOW IS CENTERED N OF THE ITCZ AXIS NEAR
12N34W ENHANCING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 100 NM
OF THE CENTER. TO THE NE...T.S. LISA CONTINUES TO PRODUCE
DISTURBED WEATHER. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS.
ALOFT...AN UPPER LEVEL TROUGH IS N OF THE BAHAMAS EXTENDING INTO
THE NW ATLC. AN UPPER LEVEL RIDGE COVERS THE CENTRAL ATLC
CENTERED NEAR 35N57W. A LONGWAVE UPPER TROUGH IS TO THE E
EXTENDING FROM THE AZORES TO NEAR 24N49W. UPPER LEVEL RIDGING
COVERS THE FAR ERN ATLC CENTERED OVER THE CAPE VERDE ISLANDS.

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

$$
WALTON/MONTALVO





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