[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 170605 AAA
TWDAT

TROPICAL WEATHER DISCUSSION...UPDATE ON HURRICANE DEAN
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI AUG 17 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
0415 UTC.

...SPECIAL FEATURES...

HURRICANE DEAN IS CENTERED NEAR 14.3N 59.8W AT 17/0600 UTC OR
ABOUT 74 NM ESE OF MARTINIQUE AND 78 NM NNW OF BARBADOS MOVING W
AT 22 KT. ON THIS TRACK DEAN WILL BE PASSING VERY NEAR THE
ISLANDS OF ST. LUCIA AND MARTINIQUE WITHIN THE NEXT SIX HOURS.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 976 MB. MAXIMUM SUSTAINED
WIND SPEED IS 85 KT WITH GUSTS TO 105 KT...MAKING DEAN A
CATEGORY TWO HURRICANE. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC OR THE INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 FOR
MORE DETAILS. DEAN CONTINUES TO MOVE RATHER QUICKLY ALONG THE
SOUTHERN PERIPHERY OF A MID LEVEL RIDGE THAT HAS MOVED IN TANDEM
WITH DEAN. DEAN IS EXPECTED TO CONTINUE TO STRENGTHEN AS IT
CROSSES THE LESSER ANTILLES LATER TODAY AND THROUGH THE
CARIBBEAN. OUTER RAINBANDS HAVE ALREADY REACHED THE CENTRAL
LESSER ANTILLES WITH HEAVY SHOWERS AND EMBEDDED THUNDERSTORMS
FROM GRENADA TO GUADELOUPE. SCATTERED MODERATE/ ISOLATED STRONG
CONVECTION IS FROM 12N-17N BETWEEN 55W-60W WITH CLUSTERS OF
SIMILAR CONVECTION COVERING A BROADER AREA FROM 11N-17N BETWEEN
52W-65W.

TROPICAL DEPRESSION ERIN CONTINUES TO WEAKEN AND MOVE FARTHER
INLAND OVER SOUTH TEXAS. ERIN IS PRODUCING HEAVY RAINS ACROSS
S/CENTRAL AND SE TEXAS. FURTHER INFORMATION ON ERIN CAN BE FOUND
IN PUBLIC ADVISORIES ISSUED BY THE HYDROMETEOROLOGICAL
PREDICTION CENTER...UNDER AWIPS HEADER TCPAT5 AND WMO HEADER
WTNT35 KWNH.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 26W S OF 20N MOVING W 15-20 KT. BROAD
LOW/MID LEVEL ROTATION IS OBSERVED WITH NO ASSOCIATED
SHOWERS/CONVECTION.

TROPICAL WAVE IS ALONG 39W S OF 19N MOVING W 15-20 KT. BROAD
LOW/MID LEVEL SLIGHTLY TILTED CURVATURE REMAINS MOSTLY TO THE W
OF THE WAVE AXIS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
FROM 11N-13N BETWEEN 39W-43W.

TROPICAL WAVE OVER THE CENTRAL CARIBBEAN IS ALONG 71W/72W S OF
19N MOVING W NEAR 20 KT. WEAK BUT WELL DEFINED LOW LEVEL
INVERTED-V CURVATURE IS IN THE CENTRAL CARIBBEAN. NO ASSOCIATED
DEEP CONVECTION WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE WITHIN A 45 NM RADIUS OF 16N73W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 16N16W 12N29W 10N37W 9N42W 14N54W
BECOMING DISTORTED DUE TO HURRICANE DEAN. SEE SPECIAL FEATURES
ABOVE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
90/120 NM OF A LINE FROM 10N16W 10N21W TO 7N27W WITH CLUSTERS OF
SIMILAR CONVECTION CONTINUING W TO 7N45W.

DISCUSSION...

GULF OF MEXICO...
THE W GULF OF MEXICO REMAINS UNDER DENSE CLOUDINESS AND WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE WAKE OF TROPICAL
DEPRESSION ERIN THAT MOVED INLAND OVER S TEXAS ON THU. AN UPPER
LEVEL RIDGE FROM THE UPPER HIGH NEAR ERIN EXTENDS S OVER E
MEXICO INDUCING AN INVERTED TROUGH ACROSS THE CENTRAL GULF.
LARGE UPPER LOW IN THE W ATLC EXTENDS ACROSS FLORIDA GENERATING
SCATTERED SHOWERS/THUNDERSTORMS WITHIN 75 NM OF THE W COAST OF
FLORIDA FROM FLORIDA KEYS TO N OF TAMPA. THE SURFACE RIDGE FROM
THE ATLC EXTENDS ACROSS FLORIDA AND OVER THE E GULF GIVING THE
REMAINDER OF THE E GULF MOSTLY CLEAR SKIES TONIGHT.

CARIBBEAN SEA...
THE LARGE UPPER LOW DIPS S ACROSS CUBA AND HISPANIOLA INTO THE N
CARIBBEAN N OF 16N W OF 70W TO THE YUCATAN PENINSULA GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS MAINLY IN THE YUCATAN
CHANNEL N OF 20N W OF 83W. THE MAIN CONCERN TONIGHT IS HURRICANE
DEAN AS IT APPROACHES THE LESSER ANTILLES AND IS ALREADY
BRINGING HEAVY SHOWERS WITH EMBEDDED THUNDERSTORMS TO THE
ISLANDS...SEE SPECIAL FEATURES ABOVE. THE ITCZ ENTERS THE E
PACIFIC REGION JUST S OF THE PANAMA BUT IS PRODUCING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS TO THE SW CARIBBEAN S OF 11N FROM
COLOMBIA TO COSTA RICA. THE REMAINDER OF THE AREA REMAINS RATHER
CLEAR TONIGHT BUT CONDITIONS WILL DETERIORATE AS HURRICANE DEAN
CROSSES THE AREA DURING NEXT FEW DAYS.

ATLANTIC OCEAN...
LARGE UPPER LOW IS CENTERED IN THE W ATLC NEAR 28N75W COVERING
THE AREA W OF 68W TO ACROSS FLORIDA AND INTO THE N CARIBBEAN BUT
WITH THE DRY NEAR STABLE AIR IS ONLY ABLE TO PRODUCE SOME
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER HISPANIOLA TO OVER
THE TURKS AND CAICOS. AN UPPER HIGH IS NEAR 26N60W AND AN UPPER
LOW IS NEAR 27N48W BUT BOTH ARE RATHER BENIGN UPPER FEATURES.
BROAD UPPER RIDGE EXTENDS E/W FROM OFF AFRICA TO 40W WITH THE
AXIS ALONG 19W/20W. DRY STABLE AIR DOMINATES THE ATLC WITH THE
EXCEPTION OF HURRICANE DEAN. A BROAD SURFACE RIDGE ALSO
DOMINATES THE ATLC INTO THE E GULF OF MEXICO ANCHORED BY A 1030
MB HIGH JUST W OF THE AZORES AND A 1029 MB HIGH JUST N OF THE
AZORES GIVING THE ATLC FAIR WEATHER AND MODERATE TRADE WINDS E
OF 60W.

$$
WALLACE



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