[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260601
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 26 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0545 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM ISAAC AT 26/0600 UTC IS NEAR 22.9N
78.0W. THIS POSITION IS ABOUT 35 MI...60 KM NE OF CANAGUA CUBA
AND ABOUT 265 MI...430 KM ESE OF KEY WEST FLORIDA. ISAAC IS
MOVING NW AT 15 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS
997 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO
60 KT. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34
KNHC FOR MORE DETAILS. THE RAIN IMPACTS OF ISAAC SPREAD ACROSS A
LARGE AREA FROM THE ERN CARIBBEAN ALL THE WAY INTO THE SE GULF
OF MEXICO. SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE ACROSS
THE BAHAMAS AND STRAITS OF FLORIDA S OF 27N W OF 70W...ALSO
INCLUDING THE NRN COASTAL WATERS OF HISPANIOLA...CUBA...AND
TURKS AND CAICOS.

A 1008 MB LOW AND ASSOCIATED TROPICAL WAVE AXIS IS LOCATED ABOUT
525 MILES W OF THE CAPE VERDE ISLANDS NEAR 15N33W MOVING WNW AT
10-15 KT. THIS FEATURE IS EMBEDDED IN THE BROAD SCALE MONSOON
GYRE ON SATELLITE IMAGERY...WITHIN A LARGE SURGE OF DEEP LAYER
MOISTURE PRESENT ACROSS MUCH OF THE CENTRAL TROPICAL ATLC. THE
SYSTEM REMAINS FAIRLY DISORGANIZED DUE TO A THICK LAYER OF
SAHARAN DUST SURROUNDING THE WAVE AND ASSOCIATED LOW. SCATTERED
MODERATE CONVECTION IS FROM 14N-21N BETWEEN 30W-36W.
ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR DEVELOPMENT...AND
THIS LOW COULD BECOME A TROPICAL DEPRESSION OVER THE NEXT DAY OR
TWO. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS

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

THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA...ENTERING THE ERN
TROPICAL ATLC OVER THE COAST OF MAURITANIA AT 20N16W CONTINUING
WSW ALONG 18N25W TO THE SPECIAL FEATURE 1008 MB LOW AND
ASSOCIATED TROPICAL WAVE NEAR 15N33W AND ALONG 9N40W TO
8N46W...WHERE THE ITCZ CONTINUES ALONG 8N53W TO NEAR THE COAST
OF TRINIDAD AND TOBAGO AT 10N60W. WHILE NO CONVECTION IS NOTED
AROUND THE ITCZ...SCATTERED MODERATE CONVECTION IS WITHIN 70 NM
ON EITHER SIDE OF THE MONSOON TROUGH BETWEEN 36W-46W.

...DISCUSSION...

THE GULF OF MEXICO...
SEVERAL OUTER BANDS OF STRONG CONVECTION ASSOCIATED TO TROPICAL
STORM ISAAC HAVE MADE THEIR WAY IN ACROSS THE ERN GULF THROUGH
THE STRAITS OF FLORIDA OVER THE PAST 24 HOURS. MOSAIC DOPPLER
RADAR IMAGERY CURRENTLY INDICATES THE ACTIVITY EXTENDS S OF 25N
E OF 84W. WEATHER CONDITIONS ARE EXPECTED TO DETERIORATE ACROSS
THE ERN GULF E OF 86W DURING THE NEXT 24 HOURS...AS ISAAC ENTERS
THE BASIN AND GAINS STRENGTH TO POSSIBLE HURRICANE STATUS. ALL
INTERESTS IN THE EASTERN GULF SHOULD MONITOR THE PROGRESS OF
ISAAC. WEAK SURFACE RIDGING EXTENDS ACROSS THE REMAINDER OF THE
BASIN PROVIDING FAIR WEATHER CONDITIONS WITH A FEW ISOLATED
SHOWERS NOTED NEAR THE IMMEDIATE COASTAL WATERS OF LOUISIANA AND
ERN TEXAS.

THE CARIBBEAN SEA...
ALTHOUGH THE CENTER OF TROPICAL STORM ISAAC IS OUT OF THE
CARIBBEAN SEA...THE BROAD CYCLONIC WIND FIELD CONTINUES TO
GENERATE STRONG CONVECTION ACROSS THE NE AND N-CENTRAL BASINS
ESPECIALLY HISPANIOLA AND PORTIONS OF ERN CUBA...WHERE LATEST
REPORTS FROM THIS COUNTRY INDICATED RAINFALL ACCUMULATIONS OF UP
TO NEAR 5 INCHES IN THE LAST 3 HOURS OVER THE FAR SE PORTION OF
THE ISLAND. FLOODING AND MUDSLIDES ARE LIKELY ACROSS THIS REGION
AS RAINFALL CONTINUES THIS MORNING. AN EARLIER SCATTEROMETER
PASS REVEALED A SURFACE TROUGH EXTENDING FROM THE COAST OF CUBA
NEAR 20N77W THROUGH A WEAK LOW AT 19N80W TO 19N85W. DUE TO THE
LARGE CIRCULATION...MUCH OF THE NORTHERN CARIBBEAN WILL CONTINUE
TO EXPERIENCE GUSTY WINDS AND HEAVY RAIN AS THE STORM CONTINUES
TOWARDS THE GULF OF MEXICO. THE NW AND SW CARIBBEAN ARE THE ONLY
AREAS STILL UNDER MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT.
ALL INTERESTS IN THE NORTHERN CARIBBEAN SHOULD CONTINUE TO
MONITOR THE PROGRESS OF ISAAC.

THE ATLANTIC OCEAN...
THE COMBINATION OF LOW-LEVEL MOISTURE BEING DRAWN ACROSS THE
BAHAMAS DUE TO TROPICAL STORM ISAAC AND DIFFLUENCE ALOFT AROUND
AN UPPER TROUGH OVER THE EASTERN GULF OF MEXICO IS HELPING
PRODUCE SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE
BAHAMAS AND STRAITS OF FLORIDA S OF 27N W OF 70W...ALSO
INCLUDING THE NRN COASTAL WATERS OF HISPANIOLA...CUBA...AND
TURKS AND CAICOS. THE UPPER LEVEL OUTFLOW-CIRRUS FROM ISAAC
COVERS THE MAJORITY OF THE WEST ATLC. ALL INTERESTS IN THE
WESTERN ATLC SHOULD CONTINUE TO MONITOR THE PROGRESS OF ISAAC.
AN ELONGATED UPPER LOW IS CENTERED NEAR 21N61W AND SUPPORTS A
WEAK SURFACE TROUGH ANALYZED FROM 26N56W TO 21N56W WITH MINIMAL
ACTIVITY IN THE VICINITY OF ITS AXIS. THE REMAINDER OF THE ATLC
BASIN DISCUSSION AREA IS DOMINATED BY A BROAD SURFACE RIDGE
ANCHORED BY A 1025 MB HIGH NEAR 34N49W AND A 1024 MB HIGH NEAR
35N30W. THE FAIR WEATHER IS ENHANCED ALOFT BY SAHARAN DUST NOTED
ON METEOSAT-9 AND GOES-R ENHANCEMENT IMAGERY. EMBEDDED IN
THIS DRY ENVIRONMENT...AN UPPER LOW WOBBLES NEAR 32N20W. EXPECT
WEATHER CONDITIONS TO CONTINUE TO DETERIORATE OVER THE WRN ATLC
AS TROPICAL STORM ISAAC MOVES INTO THE FLORIDA STRAITS.

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

$$

GARCIA




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