[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE AUG 21 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...
HURRICANE DEAN IS CENTERED NEAR 19.7N 92.2W...OR 95 NM W OF
CAMPECHE MEXICO AT 22/0000 UTC MOVING W AT 17 KT. MAXIMUM
SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 90 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 970 MB. PLEASE SEE THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
AND THE LATEST PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR
MORE DETAILS. HURRICANE DEAN AS EMERGED INTO THE S GULF OF
MEXICO IN THE BAY OF CAMPECHE LOSING STRENGTH AS IT CROSSED THE
YUCATAN PENINSULA. DEAN RETAINS ITS INNER CORE AND COULD BECOME
A MAJOR HURRICANE AGAIN BEFORE MAKING LANDFALL OVER MEXICO LATE
WED. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 20N
TO INLAND OVER S MEXICO FROM 90W-95W. OUTER RAINBANDS WITH
SCATTERED THUNDERSTORMS ARE OVER THE W GULF S OF 28N W OF 91W TO
THE COAST OF MEXICO AND SE TEXAS.

...TROPICAL WAVES...
TROPICAL WAVE IS FROM 5N51W TO 21N56W MOVING W 15-20 KT.
ALTHOUGH THIS WAVE HAS A WELL DEFINED INVERTED-V CURVATURE TO A
RATHER HIGH AMPLITUDE THERE IS NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IS ALONG 69W S OF 29N MOVING W 15-20 KT. VERY
BROAD HIGH AMPLITUDE WAVE WITH A WELL DEFINED INVERTED-V
CURVATURE. THIS IS HAS MOVED INTO AN AREA NOT FAVORABLE FOR
FURTHER DEVELOPMENT. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 120/150 NM OF LINE FROM 19N61W 28N68W
TO THE BAHAMAS NEAR 23N75W. NO ASSOCIATED CONVECTION IN THE
CARIBBEAN.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N15W 10N31W 8N43W 10N50W 7N59W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N TO THE ITCZ AXIS
BETWEEN 15W-26W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 5N-10N BETWEEN 32W-50W AND FROM 9N-13N
BETWEEN 52W-55W.

DISCUSSION...

GULF OF MEXICO...
THE MAIN FOCUS THIS EVENING REMAINS HURRICANE DEAN THAT HAS
MOVED OFF THE YUCATAN PENINSULA INTO THE BAY OF CAMPECHE. SEE
SPECIAL FEATURES ABOVE. AN UPPER RIDGE EXTENDS ACROSS THE W
GULF FROM THE UPPER HIGH LOCATED NEAR DEAN TO OVER LOUISIANA
ENHANCING THE ACTIVITY OF THE OUTER RAINBANDS ASSOCIATED DEAN. A
WEAK UPPER HIGH IN THE W ATLC EXTENDS ACROSS FLORIDA TO OVER THE
E GULF GIVING THE AREA DRY STABLE AIR. SOME LATER AFTERNOON LOW
LEVEL THUNDERSTORMS HAVE DRIFTED OFF THE SW COAST OF FLORIDA
INTO FLORIDA BAY AND OFF W CUBA INTO THE YUCATAN CHANNEL.
OTHERWISE...THE E GULF E OF 90W IS CLEAR THIS EVENING.

CARIBBEAN SEA...
IN THE WAKE OF DEAN...THE WINDS ARE BEGINNING TO DIMINISH WITH
THE SEAS SUBSIDING OVER THE NEXT 12 TO 24 HOURS. A BROAD UPPER
LOW DOMINATES THE CARIBBEAN AND IS CENTERED OFF THE S COAST OF
HAITI NEAR 18N74W EXTENDING AN UPPER TROUGH N OVER THE W ATLC
WITH A WEAKER UPPER TROUGH EXTENDING WSW TO NEAR 16N81W. THIS
UPPER LOW IS DRAWING TROPICAL MOISTURE ACROSS THE S CARIBBEAN
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 14N W
OF 78W WITH SOME MID LEVEL CYCLONIC ROTATION OFF THE COAST OF
COLOMBIA NEAR 12N78W.

ATLANTIC OCEAN...
WEAK UPPER HIGH IS OVER THE W ATLC NEAR 30N79W COVERING THE AREA
W OF 75W AND EXTENDING INTO THE E GULF OF MEXICO. DRY STABLE AIR
COVERS THE FAR W ATLC W OF 75W WITH SOME LOW LEVEL ISOLATED
SHOWERS/THUNDERSTORMS BROUGHT IN BY MODERATE EASTERLY SURFACE
FLOW OVER THE N BAHAMA ISLANDS. BROAD UPPER TROUGH EXTENDS FROM
THE UPPER LOW JUST S OF HAITI TO NEAR 28N67W. A TROPICAL WAVE IS
BENEATH THIS UPPER TROUGH ENHANCING SHOWERS/THUNDERSTORMS
ASSOCIATED WITH THE TROPICAL WAVE. A BENIGN UPPER HIGH/LOW ARE
OVER THE CENTRAL ATLC WHILE TYPICAL UPPER RIDGING EXTENDS E FROM
AFRICA OUT TO 27W. LARGE SURFACE RIDGE REMAINS IN CONTROL OF THE
ATLC TO ACROSS THE SE US AND N GULF OF MEXICO. ALL OF THIS IS
PRODUCING ABUNDANT STABLE CONDITIONS AND MODERATE TRADE WINDS
ACROSS THE ATLC WITH THE EXCEPTION OF THE AREA ASSOCIATED WITH
THE TROPICAL WAVE.

$$
WALLACE




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