[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 252348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION MATTHEW IS CENTERED INLAND OVER THE NORTHERN
GUATEMALA REGION NEAR 17.4N 89.4W AT 25/2100 UTC OR ABOUT 105
MILES SOUTHWEST OF CHETUMAL MEXICO MOVING NW AT 12 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
AND MEXICO FROM 15N-19N BETWEEN 89W-92W...WITH NUMEROUS
MODERATE/SCATTERED STRONG CONVECTION FROM 11N-21N BETWEEN
78W-94W.

TROPICAL STORM LISA IS CENTERED NEAR 23.7N 28.4W AT 25/2100 UTC
OR ABOUT 605 MILES NORTH-NORTHWEST OF THE CAPE VERDE ISLANDS
MOVING N AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB.
MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 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 23N-27N
BETWEEN 25W-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 5N12W 6N20W 4N30W 5N40W 7N50W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM
EITHER SIDE OF THE AXIS BETWEEN 18W-43W. A MESOSCALE COMPLEX IS
ALONG THE WEST COAST OF AFRICA FROM SIERRA LEONE TO
GUINEA-BISSAU BRINGING MODERATE TO ISOLATED STRONG CONVECTION
WITHIN 100 NM OFFSHORE.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH ENTERS THE NE GULF THROUGH THE FLORIDA
PANHANDLE NEAR 30N85W AND EXTENDS SW TO THE CENTRAL GULF NEAR
25N88W. THE TROUGH IS SUPPORTED BY A LONGWAVE UPPER TROUGH
EXTENDING ALONG THE SE CONUS INTO THE NORTHERN GULF COAST. WEAK
UPPER LEVEL CYCLONIC ROTATION IS EMBEDDED IN THE UPPER TROUGH
NEAR 28N89W. ALSO...UPPER DIFFLUENCE AROUND THE TROUGH ALONG
WITH SIGNIFICANT MOISTURE ACROSS THE AREA IS ENHANCING SCATTERED
SHOWERS AND THUNDERSTORMS N OF 27N BETWEEN 84W-92W. SCATTERED
SHOWERS AND THUNDERSTORMS ARE ALSO OFF THE MEXICO/TEXAS COAST
FROM 21N-28N W OF 95W. EXPECT SHOWERS AND THUNDERSTORMS TO
CONTINUE ACROSS MUCH OF THE SOUTHERN BASIN AS MOISTURE
ASSOCIATED WITH T.D. MATTHEW MOVES OVER THIS REGION.

CARIBBEAN SEA...
SIGNIFICANT MOISTURE AND BROAD CYCLONIC FLOW ASSOCIATED WITH
T.D. MATTHEW CONTINUES TO IMPACT MUCH OF THE WESTERN CARIBBEAN
PRODUCING STRONG SHOWERS AND THUNDERSTORMS W OF 78W. WATER VAPOR
IMAGERY SHOWS A BROAD UPPER LEVEL LOW CENTERED OVER THE FAR
EASTERN CUBA ENHANCING SCATTERED SHOWERS AND THUNDERSTORMS OVER
THE CENTRAL CARIBBEAN BETWEEN 69W AND 78W. FARTHER E...A WEAK
UPPER LEVEL TROUGH ACROSS THE LESSER ANTILLES IS SUPPORTING
SCATTERED SHOWERS/THUNDERSTORMS S OF 15N E OF 69W. EXPECT
CONTINUED SHOWER AND THUNDERSTORM ACTIVITY ACROSS MUCH OF THE
BASIN OVER THE NEXT SEVERAL DAYS.

ATLANTIC OCEAN...
SURFACE RIDGING AROUND A 1021 MB HIGH CENTERED E OF BERMUDA NEAR
34N58W DOMINATES THE SW ATLC. A FEW ISOLATED SHOWERS ARE ACROSS
THE BAHAMAS AND N OF HISPANIOLA AROUND AN UPPER LEVEL LOW
CENTERED OVER THE FAR EASTERN CUBA. A WEAK 1014 MB LOW IS
CENTERED NEAR 29N48W SUPPORTING A FEW ISOLATED SHOWERS WITHIN 30
NM OF THE CENTER. A SECOND 1011 MB LOW IS CENTERED N OF THE ITCZ
AXIS NEAR 12N34W ENHANCING SCATTERED SHOWERS AND THUNDERSTORMS
WITHIN 60 NM OF THE CENTER. T.S. LISA CONTINUES TO PRODUCE
DISTURBED WEATHER OVER THE EAST ATLC. SEE SPECIAL FEATURES ABOVE
FOR MORE DETAILS. ALOFT...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

$$

GARCIA




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