[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 24 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 1715 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM ISAAC AT 24/1800 UTC IS NEAR 16.8N
71.4W. THIS POSITION IS ABOUT 135 MI...215 KM SSE OF PORT AU
PRINCE HAITI...OR ABOUT 160 MI...255 KM SW OF SANTO DOMINGO
DOMINICAN REPUBLIC. ISAAC IS MOVING NW AT 12 KNOTS. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 55 KT WITH GUSTS TO 65 KT. PLEASE READ
THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34 KNHC FOR MORE
DETAILS. SCATTERED MODERATE TO STRONG CONVECTION IS S OF
HISPANIOLA FROM 12N-17N BETWEEN 67W-74W. A LARGE FEEDER BAND IS
E OF THE CENTER WITH SCATTERED MODERATE CONVECTION FROM 12N-19N
BETWEEN 64W-67W TO INCLUDE PUERTO RICO.

THE CENTER OF POST-TROPICAL CYCLONE JOYCE AT 24/1500 UTC IS NEAR
17.8N 46.2W MOVING WNW AT 14 KNOTS. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1009 MB. THE MAXIMUM SUSTAINED WIND SPEEDS
ARE 30 KT WITH GUSTS TO 40 KT. PLEASE READ THE LAST FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC AND THE
LAST PUBLIC ADVISORY...MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS.
SATELLITE IMAGERY INDICATES THAT THE CENTER OF CIRCULATION HAS
BECOME ILL DEFINED...AND THE CIRCULATION ITSELF MAY NOT EVEN BE
CLOSED ANYMORE. JOYCE IS BEING AFFECTED BY 20 KT OF
SOUTH-SOUTHEASTERLY SHEAR...AND IT IS EMBEDDED IN A DRY
MID-LEVEL ENVIRONMENT. SCATTERED MODERATE CONVECTION IS N OF THE
CENTER FROM 19N-24N BETWEEN 45W-48W.

A 1008 MB LOW IS S OF THE CAPE VERDE ISLANDS NEAR 13N23W. A
TROPICAL WAVE EXTENDS FROM 21N19W TO 17N22W TO THE LOW CENTER.
THE SYSTEM IS MOVING WSW AT 13 KT. WIDELY SCATTERED MODERATE
CONVECTION IS N OF THE LOW FROM 12N-18N BETWEEN 22W-28W...AND S
OF THE LOW FROM 7N-12N BETWEEN 22W-31W. SOME DEVELOPMENT OF THIS
SYSTEM IS POSSIBLE DURING THE NEXT COUPLE OF DAYS. THIS SYSTEM
HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE VICINITY OF THE CAPE VERDE ISLANDS.
SEE ABOVE.

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

AN ITCZ IS S OF POST-TROPICAL CYCLONE JOYCE FROM 11N46W TO THE
COAST OF GUYANA AT 7N59W. SCATTERED SHOWERS ARE WITHIN 60 NM OF
THE AXIS.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 1500 UTC...WEAK SURFACE RIDGING IS OVER THE NE GULF OF
MEXICO WITH FAIR WEATHER...WHILE SURFACE TOUGHING AND CONVECTION
IS ENTERING THE STRAITS OF FLORIDA DUE TO APPROACHING ISAAC.
FURTHER W...A 1013 MB LOW IS OVER SE TEXAS NEAR 30N94W PRODUCING
SCATTERED MODERATE CONVECTION OVER THE NW GULF FROM 27N-30N
BETWEEN 93W-96W. SCATTERED SHOWERS ARE ALSO OVER THE BAY OF
CAMPECHE FROM 17N-23N BETWEEN 91W-95W. IN THE UPPER LEVELS...THE
BASE OF AN UPPER LEVEL TROUGH IS OVER THE E GULF E OF 90W. UPPER
LEVEL DIFFLUENCE W OF THE TROUGH IS PRODUCING THE SHOWERS OVER
THE BAY OF CAMPECHE. EXPECT ADDITIONAL CONVECTION OVER THE W
GULF OVER THE NEXT 24 HOURS. ALSO EXPECT MORE CONVECTION OVER W
CUBA AND THE SE GULF OVER THE NEXT 24 HOURS DUE TO ISAAC.

THE CARIBBEAN SEA...
T.S.ISAAC IS PRODUCING CONSIDERABLE CONVECTION OVER THE EASTERN
AND CENTRAL CARIBBEAN. SEE ABOVE. TROPICAL STORM WARNINGS ARE IN
EFFECT FOR PORTIONS OF THE CARIBBEAN. A CONSIDERABLE AMOUNT OF
RAIN AND SHOWERS ARE ALSO OVER THE LEEWARD AND WINDWARD ISLANDS
E OF ISAAC. SIMILAR RAIN AND SHOWERS ARE INLAND OVER N VENEZUELA
AND N COLOMBIA DUE TO ISAAC. ELSEWHERE...WIDELY SCATTERED
MODERATE CONVECTION IS OVER THE NW CARIBBEAN S OF THE YUCATAN
CHANNEL FROM 18N-21N BETWEEN 83W-86W DUE TO UPPER LEVEL
DIFFLUENCE. ISAAC WILL BE THE DOMINATE WEATHER SYSTEM OVER THE
CARIBBEAN FOR THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
A CONSIDERABLE AMOUNT OF RAIN AND SHOWERS ARE N OF CUBA AND OVER
THE BAHAMAS DUE TO ISAAC. A 1023 MB HIGH IS CENTERED OVER THE
CENTRAL ATLANTIC NEAR 32N42W. AFRICAN DUST EXTENDS FROM 10N-34N
E OF 33W...AND FROM 10N-27N BETWEEN 33W-65W. IN THE UPPER
LEVELS...AN UPPER LEVEL LOW IS CENTERED NEAR 24N53W PRODUCING
SHEAR ON POST-TROPICAL CYCLONE JOYCE. SCATTERED SHOWERS ARE N OF
THE UPPER LOW CENTER FROM 27N-30N BETWEEN 51W-54W. ANOTHER LARGE
UPPER LEVEL LOW IS OVER THE E ATLANTIC NEAR 30N21W.

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

$$
FORMOSA





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