[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 262343
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON SEP 26 2011

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2300 UTC.

...SPECIAL FEATURES...

TROPICAL STORM PHILIPPE IS CENTERED NEAR 15.4N 34.4W AT 26/2100
UTC OR ABOUT 600 NM W OF THE CAPE VERDE ISLANDS MOVING NW AT 7
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. MAXIMUM
SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. NUMEROUS
STRONG CONVECTION IS FROM 13N-16N BETWEEN 32W-35W...WITH
MODERATE CONVECTION ELSEWHERE FROM 12N-17N BETWEEN 32W-35W. SEE
LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.

A 1011 MB LOW...REMNANT LOW OF OPHELIA...IS CURRENTLY CENTERED
NE OF THE NRN LEEWARD ISLANDS NEAR 19N60W. A SURFACE TROUGH
EXTENDS THROUGH THE LOW CENTER ALONG 21N57W 17N60W TO 17N65W
DEPICTING SOME OF THE LINES OF CONVERGENCE INTO THE LOW CENTER.
CURRENTLY NUMEROUS STRONG CONVECTION IS SE OF THE CENTER FROM
17N-19N BETWEEN 57W-60W...WITH SCATTERED MODERATE CONVECTION
ELSEWHERE FROM 15N-21N BETWEEN 56W-62W. THE LOW IS EXPECTED TO
DRIFT W-NW OVER THE NEXT COUPLE OF DAYS AND HAS THE POTENTIAL
FOR FURTHER DEVELOPMENT. EVEN THOUGH IT IS EXPECTED TO STAY N OF
THE ISLANDS...CONVECTION ASSOCIATED WITH THE LOW COULD IMPACT
THE LEEWARD ISLANDS.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 17N47W TO 11N45W MOVING W AT 5-10
KT. THE WAVE REMAINS WEAK AND WITH LOW-AMPLITUDE...BUT IS STILL
DISCERNIBLE IN SATELLITE IMAGERY AND SATELLITE WINDS. VERY DRY
AIR IS ALOFT OVER THE WAVE WHICH IS INHIBITING DEEP CONVECTION.
FORECAST GUIDANCE INDICATES THAT THE WAVE WILL CONTINUE TO MOVE
W-NW OVER THE NEXT COUPLE OF DAYS BEFORE DISSIPATING LATER IN
THE WEEK.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH HAS BEGUN TO BUILD BACK IN BEHIND T.S.
PHILIPPE AND CURRENTLY EXTENDS FROM THE AFRICAN COAST NEAR
13N17W TO 11N24W. A FEW WIDELY ISOLATED SHOWERS ARE FROM 2N-12N
BETWEEN 19W-32W.

...DISCUSSION...

GULF OF MEXICO...
MAINLY WLY FLOW ALOFT DOMINATES THE GULF OF MEXICO THIS EVENING
WITH AN UPPER LEVEL TROUGH TO THE N OVER THE ERN CONUS AND AN
UPPER LEVEL RIDGE TO THE S CENTERED OVER SRN MEXICO. WATER VAPOR
IMAGERY INDICATES MOSTLY DRY AIR ALOFT COVERS THE BASIN WHICH IS
HELPING MAINTAIN MOSTLY FAIR CONDITIONS W OF 88W WITH WEAK
ANTI-CYCLONIC SURFACE FLOW. HOWEVER...A SHORTWAVE UPPER TROUGH
IS EXTENDING SWD FROM THE MAIN TROUGH WHICH HAS HELPED MAINTAIN
A SURFACE TROUGH EXTENDING FROM NRN FLORIDA NEAR 31N83W ACROSS
THE BIG BEND OF FLORIDA TO NEAR 25N84W. SCATTERED
SHOWERS/THUNDERSTORMS...SOME HEAVY...ARE E OF THE TROUGH AXIS
ACROSS THE ENTIRE FLORIDA PENINSULA AND STRAITS OF FLORIDA INTO
CUBA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO W OF THE
TROUGH AXIS FROM 23N-26N BETWEEN 84W-88W. EXPECT MOIST
CONDITIONS TO REMAIN ACROSS FLORIDA OVER THE NEXT 24 HOURS WITH
WEAK SURFACE RIDGING BUILDING OVER THE REMAINDER OF THE GULF.

CARIBBEAN SEA...
UPPER LEVEL RIDGING EXTENDING FROM SRN MEXICO EXTENDS OVER THE
NW CARIBBEAN WHERE MOSTLY FAIR WEATHER PREVAILS. A FEW
SHOWERS/THUNDERSTORMS EXTEND S OF WRN CUBA DUE TO MOISTURE TO
THE N OVER THE FAR ERN GULF AND FLORIDA. TO THE S...CONFLUENCE
NEAR THE MONSOON TROUGH AXIS EXTENDING FROM COSTA RICA TO NRN
COLOMBIA IS HELPING PRODUCE SCATTERED SHOWERS/THUNDERSTORMS S OF
16N BETWEEN 71W-81W...AND S OF 13N W OF 81W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO ACROSS COSTA RICA AND
NICARAGUA. SOME OF THE ACTIVITY N OF THE MONSOON TROUGH IS BEING
FURTHER ENHANCED BY DIFFLUENCE ALOFT AROUND THE BASE OF AN UPPER
LEVEL TROUGH EXTENDING ACROSS ERN HISPANIOLA TO N OF THE
COLOMBIA/VENEZUELA BORDER. THE FAR ERN CARIBBEAN IS UNDER CLEAR
SKIES THIS EVENING WITH MODERATE DRY AIR ALOFT. THE REMNANT LOW
OF OPHELIA IS CURRENTLY NE OF THE NRN LEEWARD ISLANDS WHICH MAY
BRING SHOWERS/THUNDERSTORMS TO THE ISLANDS OVER THE NEXT DAY OR
SO. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS ON THE
SYSTEM.

ATLANTIC OCEAN...
A NARROW UPPER LEVEL RIDGE EXTENDS FROM CENTRAL CUBA ACROSS THE
NW BAHAMAS TO NEAR 32N76W. A SHORTWAVE UPPER TROUGH LIES TO THE
W NEAR THE W COAST OF FLORIDA. THIS PATTERN IS PRODUCING
DIFFLUENT FLOW ALOFT OVER THE FLORIDA PENINSULA AND THE COASTAL
WATERS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE CURRENTLY W
OF 30W AND ACROSS FLORIDA. ANOTHER UPPER LEVEL TROUGH IS TO THE
E ALONG 71W. DIFFLUENT FLOW AROUND THE ERN SIDE OF THIS TROUGH
IS ALSO HELPING SUPPORT ISOLATED SHOWERS/THUNDERSTORMS FROM
19N-25N BETWEEN 65W-70W. AT THE SURFACE...RIDGING DOMINATES
AROUND A 1020 MB HIGH CENTERED NEAR 32N68W. NE OF THE LEEWARD
ISLANDS A 1011 MB LOW...REMNANTS OF OPHELIA...IS CENTERED NEAR
19N60W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. FARTHER
E...AN UPPER LEVEL RIDGE COVERS THE CENTRAL ATLC CENTERED NEAR
28N55W WITH ANOTHER UPPER LEVEL TROUGH ALONG 34W. THIS UPPER
TROUGH IS SUPPORTING A SURFACE LOW N OF THE DISCUSSION AREA. A
COLD FRONT ASSOCIATED WITH THE LOW EXTENDS ALONG 32N32W 27N36W
24N46W. ISOLATED SHOWERS ARE WITHIN 120 NM E OF THE FRONT. WEAK
SURFACE RIDGING AROUND A 1022 MB HIGH N OF THE MADEIRA ISLANDS
COVERS THE FAR ERN ATLC SUPPORTED BY AN UPPER LEVEL RIDGE ALONG
21W.

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

$$
WALTON





This weather bulletin was brought to you by:
www.nashvilleweather.net