[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 290525
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU SEP 29 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.

...SPECIAL FEATURE...

W CARIBBEAN TROPICAL WAVE PREVIOUSLY ALONG 81W IS NOW JUST A
1008 MB LOW NEAR 16N81W MOVING WNW NEAR 10 KT. ORGANIZATION HAS
CHANGED LITTLE OVER THE PAST SEVERAL HOURS BUT THE UPPER LEVEL
WINDS ARE BECOMING MORE FAVORABLE FOR DEVELOPMENT INTO A
TROPICAL SYSTEM. THIS AREA HAS THE POTENTIAL OF BECOMING A
TROPICAL CYCLONE WITHIN THE NEXT DAY OR TWO. SCATTERED/NUMEROUS
STRONG CONVECTION IS NE OF THE LOW FROM 17N-22N BETWEEN 77W-81W.

...TROPICAL WAVES...

CENTRAL ATLC TROPICAL WAVE IS ALONG 36W/37W S OF 16N MOVING W
5-10 KT. BROAD CYCLONIC CURVATURE IS OBSERVED IN THE MID LEVEL
CLOUDS JUST TO THE E OF THE WAVE AXIS ON INFRARED SATELLITE
IMAGERY. NO ASSOCIATED DEEP CONVECTION.

A 1012 MB LOW IS CENTERED NEAR 13.5N46W DRIFTING W. THE LOW IS
BENEATH UPPER SE FLOW AND MOVING INTO AN AREA OF DRY AIR.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 11N-16N BETWEEN 44W-49W.

W TROPICAL ATLC TROPICAL WAVE IS ALONG 54W S OF 19N MOVING W
10-15 KT. WELL DEFINED HIGH AMPLITUDE WAVE WITH SIGNATURE
CURVATURE IN THE LOW CLOUDS AND NO ASSOCIATED DEEP CONVECTION.

...ITCZ...

ITCZ IS CENTERED ALONG 10N13W 8N19W 10N37W 14N48W 12N62W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-8N
BETWEEN 42W-46W. CLUSTERS OF SIMILAR CONVECTION ARE FROM 4N-7N E
OF 19W TO INLAND OVER AFRICA.

...DISCUSSION...

THE GULF OF MEXICO...
BROAD UPPER RIDGING ANCHORED OVER E TEXAS COVERS THE GULF W OF
86W ADVECTING VERY DRY CONTINENTAL AIR AND STRONG SUBSIDENCE
OVER THE GULF N OF 22N W OF 83W. A CUT-OFF UPPER LOW IS LOCATED
IN THE W ATLC DRAWING MOISTURE FROM THE CARIBBEAN ACROSS THE
STRAITS OF FLORIDA GIVING THE AREA SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS. S MEXICO AND THE YUCATAN PENINSULA REMAIN
MOISTURE LADENED WITH CLUSTERS OF SHOWERS/THUNDERSTORMS THAT MAY
DRIFT INTO THE FAR S GULF OVERNIGHT. AT THE SURFACE...A 1009 MB
LOW IS IN THE N GULF NEAR 29N88W WITH A TRAILING SURFACE TROUGH
EXTENDING TO 25N89W. ISOLATED SHOWERS ARE N OF 24N W OF THE
LOW/TROUGH.

CARIBBEAN...
AN UPPER RIDGE DOMINATES THE CARIBBEAN ANCHORED NEAR 17N80W AND
COVERS THE CARIBBEAN W OF AN UPPER TROUGH THAT EXTENDS FROM THE
CENTRAL ATLC OVER THE E CARIBBEAN. THE SURFACE LOW IN THE
SPECIAL FEATURES IS IN THIS AREA. TROPICAL MOISTURE IS ABUNDANT
OVER THE CARIBBEAN W OF 70W GENERATING CLUSTERS OF SCATTERED
SHOWERS/STRONG THUNDERSTORMS WITH SCATTERED MODERATE/STRONG
CONVECTION OVER HAITI AND E CUBA N OF 18N BETWEEN 72W-77W. AN
UPPER TROUGH EXTENDS INTO THE E CARIBBEAN JUST ACROSS THE
LEEWARD ISLANDS N OF 11N E OF 66W WITH SHOWERS/STRONG
THUNDERSTORMS WITHIN 60 NM OF LINE FROM 12N65W ACROSS TRINIDAD
AND TOBAGO TO 11N60W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
DOT THE REMAINDER OF THE E CARIBBEAN E OF 70W.

ATLANTIC...
A CUT-OFF UPPER LOW IS IN THE W ATLC NEAR 29N78W WITH A TROUGH
EXTENDING TO THE COAST OF CUBA NEAR 23N79W DRAWING TROPICAL
MOISTURE ACROSS CUBA AND HISPANIOLA. THE UPPER HIGH ANCHORED IN
THE W CARIBBEAN EXTENDS A RIDGE NE THROUGH THE WINDWARD PASSAGE
TO BEYOND 32N71W. DIFFLUENCE AND THE ABUNDANT TROPICAL MOISTURE
IS GENERATING SCATTERED MODERATE/STRONG CONVECTION S OF 24N OVER
HAITI AND E CUBA FROM 71W-76W INCLUDING THE S BAHAMA ISLANDS. AN
UPPER TROUGH IS IN THE CENTRAL ATLC EXTENDING FROM AN UPPER LOW
NEAR 30N56W S TO A SECOND UPPER LOW NEAR 21N58W INTO THE DEEP
TROPICAL AND THE E CARIBBEAN NEAR 11N61W. DIFFLUENCE AT THE BASE
OF THE DEEP LAYERED TROUGH IS GENERATING THE SHOWERS/
THUNDERSTORMS OVER THE E CARIBBEAN AND THE WINDWARD ISLANDS. A
STRONG UPPER HIGH IS E OF THIS TROUGH NEAR 18N44W WITH A SHARP
RIDGE EXTENDING N TO BEYOND 32N40W. AN UPPER LOW IN THE E ATLC
IS CENTERED NEAR 25N26W WITH A TROUGH DIGGING S TO OVER THE CAPE
VERDE ISLANDS NEAR 15N27W. AT THE SURFACE...THE SUBTROPICAL
RIDGE AGAIN DOMINATES THE AREA WITH WEAK TROUGHING IN THE
CENTRAL ATLC N OF 30N.

$$
WALLACE


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