[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 312341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 31 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2245 UTC.

...SPECIAL FEATURES...

THE CENTER OF HURRICANE KIRK AT 31/2100 UTC WAS NEAR 32.2N 50.2W
MOVING NORTH AT 11 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS
981 MB WITH MAXIMUM SUSTAINED WINDS OF 80 KT WITH GUSTS TO 100
KT. PLEASE READ THE NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC AND THE PUBLIC ADVISORY MIATCPAT1
/WTNT31 KNHC FOR MORE DETAILS. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 31N-33N BETWEEN 49W-51W.

THE CENTER OF TROPICAL STORM LESLIE AT 31/2100 UTC WAS NEAR
16.7N 51.0W MOVING WEST-NORTHWESTWARD AT 16 KNOTS. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 999 MB WITH MAXIMUM SUSTAINED WINDS
OF 55 KT WITH GUSTS TO 65 KT. PLEASE READ THE NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND THE
PUBLIC ADVISORY...MIATCPAT1/ WTNT31 KNHC FOR MORE DETAILS.
NUMEROUS STRONG CONVECTION IS FROM 15N-18N BETWEEN 50W-53W WITH
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 12N-19N
BETWEEN 49W-55W.

...TROPICAL WAVES...

TROPICAL WAVE IS E OF THE CAPE VERDE ISLANDS ALONG 19N19W TO A
1008 MB SURFACE LOW AT 15N21W. THE SURFACE LOW WAS IDENTIFIED IN
A SCATTEROMETER PASS FROM EARLIER TODAY. THE CIRCULATION OF THE
WAVE IS RATHER LARGE AND CONTINUES BOTH WEST OF THE CAPE VERDE
ISLANDS AND EAST TO AFRICA MAKING IT DIFFICULT TO LOCATE THE
EXACT AXIS. MODEL GUIDANCE INDICATES THAT THE WAVE WILL BE SLOW
MOVING FOR AT LEAST THE NEXT 24 HOURS. CURRENTLY ISOLATED
MODERATE CONVECTION IS FROM 7N-9N BETWEEN 21W-24W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA AND SPLITTING AT THE
COAST DUE TO PRESENCE OF THE TROPICAL WAVE IN THE E ATLC. IT
CONTINUES FROM A LOW CENTER ATTACHED TO THE WAVE AT 15N21W
CONTINUING ALONG 10N25W 9N32W. BESIDES ASSOCIATED WITH THE
TROPICAL WAVE...NO DEEP CONVECTION IS NOTED.

...DISCUSSION...

THE GULF OF MEXICO...
SURFACE RIDGING COVERS THE GULF OF MEXICO EXTENDING FROM A PAIR
OF SURFACE HIGH CENTERS OVER GEORGIA AND TO THE EAST OF GEORGIA
OVER ATLC WATERS. THIS PATTERN IS PROVIDING RETURN FLOW ACROSS
THE BASIN WITH WIND SPEEDS UP TO 20 KT ACROSS THE CENTRAL GULF.
THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED OVER THE
N CENTRAL GULF. HOWEVER...AN INVERTED UPPER TROUGH IS MOVING OFF
THE YUCATAN PENINSULA INTO THE SW GULF SUPPORTING A LARGE AREA
OF SHOWERS/THUNDERSTORMS ACROSS THE PENINSULA MOVING WESTWARD
INTO THE BAY OF CAMPECHE. ISOLATED SHOWERS/THUNDERSTORMS ARE
ALSO ACROSS THE NW GULF EMBEDDED WITHIN THE SURFACE RETURN FLOW.
MOSTLY CLEAR SKIES ARE NOTED ELSEWHERE. EXPECT LITTLE CHANGE
OVER THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
SHOWERS/THUNDERSTORMS COVER MUCH OF THE SW CARIBBEAN AND CENTRAL
AMERICA DUE TO BOTH THE PRESENCE OF THE MONSOON TROUGH ACROSS
COSTA RICA AND PANAMA...AND DIFFLUENCE ALOFT BETWEEN AN INVERTED
UPPER TROUGH OVER THE YUCATAN PENINSULA TO THE NORTH AND A VERY
NARROW UPPER RIDGE BETWEEN THAT UPPER TROUGH AND A SECOND
BROADER ONE COVERING THE CENTRAL AND EASTERN CARIBBEAN. THE
STRONGEST ACTIVITY IS MOVING TROUGH NICARAGUA AND HONDURAS. THE
REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR CONDITIONS
WITH CLEAR SKIES. DRY AIR ALOFT AROUND THE BROAD INVERTED UPPER
TROUGH OVER THE MAJORITY OF THE BASIN IS HELPING PROVIDE THOSE
FAIR CONDITIONS. A FEW ISOLATED SHOWERS ARE IN THE SE CARIBBEAN
NEAR A SURFACE TROUGH EXTENDING FROM 16N61W TO 11N64W. EXPECT
THE SURFACE TROUGH TO MOVE WESTWARD AND DISSIPATE WITH LITTLE
CHANGE ELSEWHERE.

THE ATLANTIC OCEAN...
A LONGWAVE UPPER TROUGH CONTINUES TO PUSH SOUTHWARD INTO THE W
ATLC SUPPORTING A SURFACE TROUGH FROM 31N65W TO 28N75W. ISOLATED
SHOWERS/THUNDERSTORMS EXTEND 175 NM SE OF THE AXIS AND 90 NM NW
OF THE AXIS. STRONG DRY AIR ALONG WITH SURFACE RIDGING ARE
BUILDING IN BEHIND THE UPPER/SURFACE TROUGH. HURRICANE KIRK AND
TROPICAL STORM LESLIE DOMINATE THE CENTRAL ATLC. SEE SPECIAL
FEATURES ABOVE FOR MORE DETAILS. SURFACE RIDGING IS ACROSS THE
EASTERN ATLC ANCHORED BY A 1024 MB HIGH NEAR 32N40W. THE HIGH IS
SUPPORTED BY AN UPPER LEVEL RIDGE EXTENDING FROM THE OUTFLOW OF
LESLIE TO E OF KIRK. AN UPPER LEVEL LOW IS TO THE EAST NEAR
31N33W SUPPORTING ISOLATED SHOWERS FROM 29N-32N BETWEEN 29W-38W.
UPPER LEVEL RIDGING COVERS THE FAR E ATLC CENTERED OVER NW
AFRICA. GOES-R ENHANCEMENT IMAGERY INDICATES THAT AN AREA OF
DUST EXTENDS FROM THE COAST OF AFRICA AROUND THE TROPICAL WAVE
IN THE E ATLC CONTINUING TO ABOUT 40W.

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

$$
WALTON





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