[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221042
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE AUG 22 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...
TROPICAL DEPRESSION FOUR IS CENTERED NEAR 12.8N 24.6W 0R ABOUT
120 NM SOUTH OF THE SOUTHERN MOST CAPE VERDE ISLANDS AT 22/0900
UTC MOVING WNW AT 14 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40
KT. SEE LATEST NHC FORECAST/ADVISORY UNDER HEADERS
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. T.D. FOUR REMAINS A
LARGE WELL-ORGANIZED SYSTEM IN SPITE OF THE LOSE OF CONVECTION
SURROUNDING THE CENTER. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 150 NM OF THE CENTER IN THE NW QUADRANT
WITH SIMILAR CONVECTION TO THE S FROM 7N-11N BETWEEN 23W-28W.
ANOTHER WAVE OF AFRICAN DUST IS N OF THE T.D WHICH USUALLY
HAMPERS CONVECTION. GRADUAL STRENGTHENING IS EXPECTED AS THE
SYSTEM REMAINS IN A FAVORABLE ENVIRONMENT.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 44W/45W S OF 20N MOVING W NEAR 20 KT.
BROAD MID LEVEL ROTATION REMAINS ON INFRARED SATELLITE IMAGERY
ALONG THE ITCZ. CONVECTION IS CONFINED TO WITHIN THE ITCZ AREA.

TROPICAL WAVE IS ALONG 59W/60W S OF 20N MOVING W NEAR 15-20 KT.
ILL-DEFINED INVERTED-V CURVATURE OBSERVED ON INFRARED SATELLITE
IMAGERY AS THE WAVE APPROACHES THE LESSER ANTILLES. CONVECTION
IS CONFINED TO WITHIN THE ITCZ AREA.

TROPICAL WAVE IN THE CARIBBEAN IS ALONG 76W/77W S OF 18N MOVING
W 15 KT. DESPITE THE WAVE BEING BENEATH AN UPPER RIDGE...WEAK
LOW LEVEL INVERTED-V CURVATURE IS OBSERVED ON INFRARED SATELLITE
IMAGERY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM
17N-20N BETWEEN 75W-78W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N15W 8N34W 10N52W 10N62W ACROSS
THE N PORTION OF SOUTH AMERICA AND PANAMA INTO THE E PACIFIC
REGION. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 7N-13N BETWEEN 41W-62W.

...DISCUSSION...
GULF OF MEXICO...
BROAD UPPER RIDGE ANCHORED OVER THE CENTRAL MISSISSIPPI VALLEY
EXTENDS OVER THE NW GULF N OF 27N W OF 90W. AN UPPER TROUGH
EXTENDS FROM AN UPPER LOW OVER NE GULF NEAR 29N84W ACROSS THE
GULF TO AN UPPER LOW INLAND OVER CENTRAL MEXICO PROVIDING ENOUGH
DIFFLUENCE OVER THE GULF TO GENERATE CLUSTERS OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS OVER THE AREA EXCEPT THE NW GULF
COAST FROM LOUISIANA THROUGH TEXAS CLEAR MOSTLY CLEAR SKIES
PREVAIL. THE STRONGEST THUNDERSTORMS ARE ALONG THE COAST OF NE
MEXICO FROM 23N-26N BETWEEN 95W-97.5W.

CARIBBEAN SEA...
BROAD UPPER RIDGE EXTENDS OVER THE W CARIBBEAN FROM AN UPPER
HIGH IN THE GULF OF HONDURAS NEAR 17N88W NE ACROSS E CUBA TO
THE CENTRAL BAHAMAS IN THE W ATLC. THIS IS PROVIDING ENOUGH
DIFFLUENCE OVER W CARIBBEAN TO GENERATE A LARGE AREA OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 15N W OF 80W WITH
AN AREA OF SCATTERED MODERATE/STRONG CONVECTION FROM 17N-21N
BETWEEN 83W-97W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS WITHIN 90 NM ALONG THE COAST OF PANAMA THROUGH NICARAGUA S OF
12N W OF 79W DUE TO THE CLOSE PROXIMITY OF THE ITCZ AXIS.
MODERATE/STRONG TRADEWINDS ARE ACROSS THE AREA.

ATLANTIC OCEAN...
BROAD UPPER LOW REMAINS SE OF BERMUDA NEAR 30N58W COVERING AN
AREA N OF 22N W OF 50W. HOWEVER...WITH DRY AIR IN PLACE THIS
FEATURE IS ONLY ABLE TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS OVER A SMALL AREA FROM 24N-28N BETWEEN
61W-71W. THE UPPER RIDGE EXTENDS FROM THE CARIBBEAN ACROSS E
CUBA TO THE CENTRAL BAHAMAS NEAR 23N72W IN THE W ATLC. THE
REMAINDER OF THE ATLC IS DOMINATED BY MOSTLY BENIGN FEATURES
WHICH INCLUDE AN UPPER TROUGH EXTENDING FROM THE E ATLC NEAR
32N19W THROUGH AN UPPER LOW NEAR 29N27W TO THE TROPICAL ATLC
NEAR 15N60W. DRY AIR REMAINS IN PLACE OVER THE ATLC...SO NO
SIGNIFICANT CLOUDS OR SHOWERS ARE ASSOCIATED WITH THIS FEATURE.
BROAD SURFACE RIDGE DOMINATES THE ATLC THUS KEEPING THE ITCZ AND
ANY DEVELOPING SYSTEMS TO THE SOUTH. SIGNIFICANT AMOUNTS OF
AFRICA DUST COVER THE E TROPICAL ATLC FROM THE ITCZ TO 24N FROM
40-65W WITH A SECOND SURGE COVERING THE FAR E ATLC BETWEEN THE
CAPE VERDE ISLANDS AND THE AFRICAN COAST.

$$
WALLACE



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