[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280600
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0415 UTC.

...SPECIAL FEATURE...
HURRICANE IRENE IS CENTERED NEAR 38.1N 75.0W AT 28/0600 UTC OR
ABOUT 13 NM SSE OF OCEAN CITY MARYLAND AND ABOUT 170 NM SSW OF
NEW YORK CITY MOVING N-NE AT 15 KT. THE LATEST MINIMUM CENTRAL
PRESSURE REPORTED BY THE HURRICANE HUNTER AIRCRAFT WAS 958 MB.
MAXIMUM SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT.
PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADER MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/
ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT4/WTNT24 KNHC FOR MORE
DETAILS. SCATTERED TO HEAVY SHOWERS WITH ISOLATED/SCATTERED
THUNDERSTORMS COVER A LARGE AREA INLAND OVER THE NE CONUS AND
WITHIN 150 NM ALONG THE COAST FROM  N OF CAPE HATTERAS NORTH
CAROLINA BORDER TO CENTRAL MAINE.

A 1012 MB LOW IS OFF THE COAST OF AFRICA NEAR 10N19W. CLUSTERS
OF SCATTERED/NUMEROUS STRONG CONVECTION ARE WITHIN 60 NM OF LINE
FROM DAKAR SENEGAL W OF THE LOW TO 10N22W. ENVIRONMENTAL
CONDITIONS APPEAR CONDUCIVE FOR DEVELOPMENT OF THIS WAVE DURING
THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD AT 9 KT. THIS
SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS.

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

THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA ENTERING THE E
TROPICAL ATLC NEAR 12N15W TO 10N18W THEN RESUMES NEAR 14N37W TO
10N48W. THE ITCZ AXIS CONTINUES FROM 10N48W ALONG 9N54W TO SOUTH
AMERICA NEAR 8N59W. SCATTERED MODERATE/STRONG CONVECTION IS
WITHIN 90 NM OF LINE FROM 5N20W 7N24W TO 11N23W. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE FROM 5N-8N BETWEEN 10W-15W...
WITHIN 150 NM S OF THE MONSOON TROUGH BETWEEN 37W-43W...AND
WITHIN 180 NM N OF THE ITCZ BETWEEN 54W-58W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH OVER THE E CONUS DIPS S OVER THE N GULF TO 27N
SUPPORTING A COLD FRONT THAT AT 28/0300 UTC EXTENDS FROM SW
GEORGIA ACROSS NE FLORIDA INTO THE GULF NEAR 30N83W ALONG 29N88W
TO 29N92W WHERE IT BECOMES STATIONARY TO INLAND OVER E TEXAS
NEAR THE LOUISIANA BORDER. SCATTERED SHOWERS/THUNDERSTORMS ARE
FROM 27N-29N E OF 90W TO JUST INLAND OVER FLORIDA NEAR TAMPA.
AN UPPER RIDGE ANCHORED OVER THE NW CARIBBEAN IS GIVING THE
REMAINDER OF THE GULF WESTERLY FLOW ALOFT LEAVING THE REMAINDER
OF THE GULF WATERS ARE UNDER CLEAR SKIES TONIGHT. THE COLD
FRONT WILL DISSIPATE THROUGH LATE MON. LOW PRESSURE IS EXPECTED
TO DEVELOP IN THE SW GULF WED AND THU. ATLC SURFACE RIDGE WILL
BUILD WESTWARD ALONG THE FAR N GULF COAST TUE THROUGH THU.

CARIBBEAN SEA...
AN UPPER RIDGE COVERS THE W CARIBBEAN W OF 75W ANCHORED NEAR
18N85W WHILE THE UPPER TROUGH OVER THE CENTRAL ATLC EXTENDS S
OVER THE REMAINDER OF THE CARIBBEAN BASIN. DEEP LAYER MOISTURE
REMAINS ACROSS THE CARIBBEAN BASIN AND COMBINED WITH THE FLOW
ALOFT IS GENERATING LARGE CLUSTERS OF SCATTERED SHOWERS/
THUNDERSTORMS OVER THE CENTRAL CARIBBEAN N OF 11N BETWEEN
70W-80W TO ACROSS HISPANIOLA...E CUBA...AND JAMAICA. THE MONSOON
TROUGH EXTENDS FROM COLOMBIA NEAR 8N76W ACROSS PANAMA INTO THE
SW CARIBBEAN ALONG 9N81W TO OVER NICARAGUA NEAR 12N84W
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND
WITHIN 45 NM ALONG THE COAST OF PANAMA BETWEEN 80W-82W. THIS IS
LEAVING MOST OF THE NW CARIBBEAN UNDER CLEAR SKIES TONIGHT
EXCEPT SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE GULF OF
HONDURAS WITHIN 60 NM ALONG THE COAST OF HONDURAS AND THE
YUCATAN PENINSULA S OF 20N W OF 84W. A SURFACE RIDGE WILL BUILD
WESTWARD OVER THE W ATLC MON THROUGH WED INCREASING TRADES OVER
THE CENTRAL AND E CARIBBEAN. THE TRADES WILL THEN WEAKEN THU AS
THE RIDGE BEGINS TO RETREAT BACK TO THE NE.

ATLANTIC OCEAN...
THE PRIMARY FOCUS TONIGHT IS HURRICANE IRENE MOVING ALONG THE
COAST OF NEW ENGLAND...SEE SPECIAL FEATURES ABOVE. THE UPPER
TROUGH THAT COVERS THE E CONUS EXTENDS INTO THE W ATLC W OF 77W
WHILE THE ASSOCIATED FRONTAL BOUNDARY REMAINS INLAND AND IN THE
GULF OF MEXICO. AN UPPER LOW IS IN THE W/CENTRAL ATLC NEAR
27N61W EXTENDING AN UPPER TROUGH S INTO THE E CARIBBEAN THROUGH
THE MONA PASSAGE SUPPORTING A 1010 MB SURFACE LOW NEAR 29N64W. A
WEAKENING SURFACE TROUGH IS TO THE E EXTENDING FROM 30N61W TO
26N58W AND A SECOND SURFACE TROUGH TO THE S EXTENDING FROM
23N56W TO 19N56W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS COVER THE AREA FROM 21N-31N BETWEEN 52W-69W. A
SURFACE RIDGE EXTENDING INTO THE REMAINDER OF THE CENTRAL ATLC
THROUGH A 1022 MB HIGH NEAR 30N51W TO 25N45W AND A SECOND
SURFACE RIDGE OVER THE E ATLC EXTENDS THROUGH 32N22W TO 28N31W.
A 1011 MB LOW IS TO THE S CENTERED NEAR 18N35W WITH A WEAK
SURFACE TROUGH ANALYZED FROM 25N30W THROUGH THE LOW TO 15N36W
WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 120 NM
EITHER SIDE OF THE SURFACE TROUGH N OF 20N. A SURFACE TROUGH IS
IN THE W TROPICAL ATLC EXTENDING FROM 16N59W TO 11N58W MOVING
TOWARD THE LESSER ANTILLES. LINGERING LARGE SWELLS GENERATED
FROM HURRICANE IRENE WILL GRADUALLY SUBSIDE THROUGH SUN NIGHT.
CENTRAL ATLC HIGH PRES WILL BUILD WESTWARD IN THE WAKE OF IRENE.
HIGH PRESSURE WILL THEN SLOWLY RETREAT AS A WEAK FRONTAL TROUGH
MOVES INTO THE NW PORTION MON NIGHT SLOWLY SHIFTING E AND
EXTENDING FROM BERMUDA TO THE CENTRAL BAHAMAS BY THU.

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

$$
PAW





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