[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU AUG 30 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 1745 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM ISAAC AT 30/1800 UTC IS NEAR 32.2N
92.3W. ISAAC HAS BEEN INLAND FOR OVER 24 HOURS. THE CURRENT
POSITION IS ABOUT 25 MI SW OF MONROE LOUISIANA. ISAAC IS MOVING
NNW AT 8 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 992 MB WITH
MAXIMUM SUSTAINED WIND SPEEDS OF 35 KNOTS GUSTING TO 45 KNOTS.
PLEASE READ THE NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/ WTNT24 KNHC AND THE PUBLIC ADVISORY... MIATCPAT4
/WTNT34 KNHC FOR MORE DETAILS. THE RESULTANT BROAD CYCLONIC
CIRCULATION CONTINUES TO IMPACT THE N-CENTRAL AND N-ERN GULF
THIS AFTERNOON. MOST OF THE ENERGY LEFT IN THIS SYSTEM IS
CONCENTRATED E AND SE OF THE CENTER...WHERE SEVERAL CONVECTIVE
BANDS ARE NOTED ON DOPPLER RADAR IMAGERY N OF 25N BETWEEN
85W-93W. EVEN THOUGH ISAAC IS NO LONGER A HURRICANE...LIFE
THREATENING HAZARDS FROM STORM SURGE...INLAND FLOODING...AND
TORNADOES ARE STILL OCCURRING. ALL RESIDENTS IN LOUISIANA...
MISSISSIPPI...AND SURROUNDING STATES SHOULD CONTINUE TO MONITOR
ALL BULLETINS THAT ARE ISSUED BY THE NATIONAL HURRICANE CENTER
AND THE LOCAL NATIONAL WEATHER SERVICE OFFICES FOR UPDATES ABOUT
THIS SYSTEM.

TROPICAL STORM KIRK WAS UPGRADED TO HURRICANE STATUS AT 30/1500
UTC...LOCATED NEAR 27.2N 49.5W. KIRK IS MOVING NW 10 KNOTS. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 989 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 65 KT WITH GUSTS TO 80 KT. PLEASE READ
THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC AND THE PUBLIC ADVISORY...MIATCPAT1/ WTNT31 KNHC FOR MORE
DETAILS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
EXTENDS UP TO 100 NM FROM THE CENTER AT ALL QUADRANTS.

THE SPECIAL FEATURE LOW PRESSURE SYSTEM AND ASSOCIATED TROPICAL
WAVE OVER THE CENTRAL TROPICAL ATLC BECAME TROPICAL DEPRESSION
TWELVE AT 30/1500 UTC...CENTERED NEAR 14.1N 43.4W. THIS SYSTEM
IS MOVING NW AT ABOUT 7 KT WITH GUSTY WINDS UP TO 40 KT.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 10N-17N
BETWEEN 42W-48W. THIS SYSTEM IS MOVING INTO A REGION OF
FAVORABLE DEVELOPMENT AND GLOBAL MODEL GUIDANCE SUGGEST IT COULD
BECOME STRONGER OVER THE NEXT 24 HOURS.

...TROPICAL WAVES...

NO TROPICAL WAVES ARE INCLUDED IN THE 30/1200 UTC SURFACE MAP
ANALYSIS.

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

THE MONSOON TROUGH EXTENDS INLAND ACROSS WEST AFRICA TO THE
COAST OF SIERRA LEONE AT 8N13W CONTINUING WNW TO 11N28W. THE
MONSOON TROUGH BEGINS AGAIN SOUTH OF TROPICAL DEPRESSION TWELVE
FROM 12N43W ALONG TO 9N53W. GIVEN THE BROAD CIRCULATION OF THIS
SYSTEM...NO OCEANIC ITCZ AXIS IS PRESENT. SCATTERED WEAK TO
ISOLATED MODERATE CONVECTION IS FROM 4N-9N E OF 30W.

...DISCUSSION...

THE GULF OF MEXICO...
ALTHOUGH THE CENTER OF TROPICAL STORM ISAAC IS WELL INLAND OVER
THE STATE OF LOUISIANA...THE RESULTANT BROAD CYCLONIC
CIRCULATION CONTINUES TO IMPACT THE N-CENTRAL AND N-ERN GULF
THIS AFTERNOON. MOST OF THE ENERGY LEFT IN THIS SYSTEM IS
CONCENTRATED E AND SE OF THE CENTER...WHERE SEVERAL CONVECTIVE
BANDS ARE NOTED ON DOPPLER RADAR IMAGERY N OF 25N BETWEEN
85W-93W. MARINE OBSERVATIONS SHOW GUSTY SOUTHERLY WINDS UP TO 40
KT IN THIS AREA. THIS SOUTHERLY FLOW ALONG WITH LOW LEVEL
MOISTURE DRAWN ACROSS THE SE IS ADVECTING SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE YUCATAN CHANNEL. FAIR WEATHER IS
ELSEWHERE ACROSS THE GULF ATTRIBUTED TO DRY AIR ALOFT WRAPPING
AROUND ISAAC. STORMY CONDITIONS WILL REMAIN ACROSS A LARGE
PORTION OF THE N-CENTRAL GULF FOR AT LEAST THE NEXT 24 HOURS.
INTERESTS IN THESE REGION SHOULD MONITOR THE PROGRESS OF ISAAC.

THE CARIBBEAN SEA...
AN ELONGATED UPPER LOW MOVES ACROSS THE NW CARIBBEAN ON WATER
VAPOR IMAGERY...CURRENTLY CENTERED NEAR 20N82W. THIS FEATURE IS
PROVIDING AN AREA OF STRONG DIFFLUENCE ALOFT OVER THE FAR SW...
GENERATING SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS
W OF 80W. SOME OF THE ACTIVITY IN THIS REGION S OF 13N IS ALSO
SUPPORTED BY THE ERN PACIFIC MONSOON TROUGH EXTENDING INTO THE
SW CARIBBEAN ACROSS COSTA RICA TO NRN COLOMBIA. THIS AREA OF
CONVECTION IS BEING DRAWN NORTHWARD ACROSS THE YUCATAN CHANNEL
INTO THE GULF OF MEXICO...IN RESPONSE OF THE BROADER/STRONGER
FLOW AROUND TROPICAL STORM ISAAC. A WEAK/SLOW MOVING SURFACE
TROUGH IS NOTED A FEW MILES E OF THE LESSER ANTILLES ANALYZED
FROM 15N60W TO TRINIDAD AND TOBAGO. THIS FEATURE IS GENERATING A
CLUSTER OF MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS OVER THE
ISLANDS OF MARTINIQUE...ST LUCIA...ST VINCENT...AND BARBADOS.
THIS SYSTEM WILL CONTINUE TO DRIFT WESTWARD DURING THE NEXT 24
HOURS WITH THE POTENTIAL FOR COASTAL FLOODING AND MUDSLIDES OVER
HIGHER TERRAIN OVER THIS GROUP OF ISLANDS. OTHERWISE...THE
REMAINDER OF THE DISCUSSION AREA IS DOMINATED BY DRY AIR ALOFT
NOTED ON WATER VAPOR IMAGERY...PROVIDING MOSTLY FAIR WEATHER
CONDITIONS WITH A FEW ISOLATED LOW-TOP SHOWERS ACROSS THE AREA.
MODERATE TO FRESH TRADEWIND FLOW IS ACROSS MUCH OF THE CENTRAL
AND EASTERN PORTIONS OF THE BASIN E OF 80W.

THE ATLANTIC OCEAN...
A FRONTAL BOUNDARY EXTENDS ALONG OUR NRN FRINGE OF OUR
DISCUSSION AREA ALONG LATITUDE 32N W OF 63W...GENERATING WIDELY
SCATTERED SHOWERS N OF 27N BETWEEN 70W-79W. SHORT RANGE COMPUTER
MODELS SUGGEST THE FRONT WILL EXPAND SE INTO OUR AREA WITH
ISOLATED MODERATE CONVECTION. ASIDE HURRICANE KIRK AND NEWLY
FORMED TROPICAL DEPRESSION TWELVE...THE REMAINDER OF THE ATLC
BASIN DISCUSSION AREA IS DOMINATED BY A SURFACE RIDGE ANCHORED
BY A 1020 MB HIGH CENTERED NEAR 26N60W...AND A BROAD UPPER LEVEL
RIDGE OF HIGH PRESSURE CENTERED W OF THE IBERIAN PENINSULA. THE
OVERALL ACTIVITY IS ENHANCED ALOFT BY SAHARAN DUST NOTED ON
GOES-R IMAGERY AND METEOSAT-9 SAL PRODUCT.

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

$$

GARCIA



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