[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 220552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED AUG 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURE...
HURRICANE DEAN IS CENTERED NEAR 20.1N 94.0W...OR 135 NM ENE OF
VERACRUZ MEXICO AT 22/0600 UTC MOVING WNW AT 17 KT. MAXIMUM
SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 980 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 IS A CATEGORY ONE HURRICANE WITH A
LARGE RAGGED EYE AND COULD STRENGTHEN AGAIN BEFORE MAKING
LANDFALL OVER MEXICO LATE TODAY. SCATTERED MODERATE/STRONG
CONVECTION IS WITHIN 150 NM OF THE CENTER IN THE W SEMICIRCLE
AND SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180
NM OF THE CENTER INT HE E SEMICIRCLE. OUTER RAINBANDS WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE GULF S OF
27N W OF 87W TO THE COAST OF MEXICO AND SE TEXAS.

...TROPICAL WAVES...
TROPICAL WAVE IS FROM 6N53W TO 20N56W 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 70W/71W S OF 30N MOVING W 15-20 KT. VERY
BROAD HIGH AMPLITUDE WAVE WITH A WELL DEFINED INVERTED-V
CURVATURE. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 75/90 NM OF LINE FROM 28N70W TO THE
CENTRAL BAHAMAS NEAR 24N75W. CLUSTERS OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 120 NM OF LINE FROM
THE LEEWARD/VIRGIN ISLANDS NEAR 18N63W TO 27N65W. NO ASSOCIATED
CONVECTION IN THE CARIBBEAN.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N13W 9N21W 11N31W 9N43W 9N58W
11N64W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-11N
BETWEEN 17W-26W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 6N-11N BETWEEN 27W-55W.

DISCUSSION...

GULF OF MEXICO...
THE MAIN FOCUS THIS EVENING REMAINS HURRICANE DEAN THAT IS IN
THE CENTRAL BAY OF CAMPECHE. SEE SPECIAL FEATURES ABOVE. AN
UPPER IS N OF HURRICANE DEAN EXTENDING AN UPPER RIDGE ACROSS THE
GULF FROM THE YUCATAN PENINSULA TO SW 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 MOSTLY DRY STABLE AIR. A SMALL AREA OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS OFF THE SW COAST OF
FLORIDA WITHIN A 60 NM RADIUS OF 26N84W. OTHERWISE...THE NE GULF
IS CLEAR TONIGHT.

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 MUCH OF THE CARIBBEAN CENTERED BETWEEN HAITI AND
JAMAICA NEAR 18N76W EXTENDING AN UPPER TROUGH NNE 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 13N W OF 72W WITH SOME MID LEVEL INVERTED TROUGH EXTENDING
FROM PANAMA NEAR 10N80W TO NEAR 14N74W. THE E CARIBBEAN REMAINS
CLEAR TONIGHT.

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 76W WITH SOME LOW LEVEL ISOLATED
SHOWERS BROUGHT IN BY MODERATE EASTERLY SURFACE FLOW ACROSS THE
N BAHAMA ISLANDS TO OVER S FLORIDA. BROAD UPPER TROUGH EXTENDS
FROM THE UPPER LOW JUST IN THE N CARIBBEAN ACROSS 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 A TYPICAL
UPPER RIDGING EXTENDS E FROM AFRICA OUT TO 30W. LARGE SURFACE
RIDGE REMAINS IN CONTROL OF THE ATLC TO ACROSS THE SE US AND N
GULF OF MEXICO WITH A WEAK 1026 MB HIGH LOCATED NEAR 31N47W. 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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