[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231032
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE SEP 23 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0945 UTC.

...SPECIAL FEATURES...
A BROAD AREA OF LOW PRESSURE IS ANALYZED AS A 1008 MB LOW ALONG
THE N COAST OF THE DOMINICAN REPUBLIC NEAR 19N70W CONTINUES TO
BRING HEAVY RAINS TO PUERTO RICO...THE DOMINICAN REPUBLIC...AND
ADJACENT WATERS. SCATTERED/NUMEROUS STRONG CONVECTION IS FROM
15N-18N BETWEEN 68W-71W WITH SCATTERED MODERATE/ISOLATED STRONG
CONVECTION FROM 14N-20N BETWEEN 67W-72W. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE FROM 15N-18N BETWEEN 63W-67W AND FROM
18N-23N BETWEEN 60W-67W. HEAVY RAINFALL WITH LIFE-THREATENING
FLASH FLOODS AND MUDSLIDES ARE EXPECTED TO CONTINUE IMPACTING
THE AREA FROM PUERTO RICO THROUGH HISPANIOLA FOR TODAY. THE
ASSOCIATED SHOWERS AND THUNDERSTORMS REMAIN POORLY ORGANIZED AT
THIS TIME DUE TO UPPER-LEVEL WESTERLY WINDS WITH LITTLE CHANGE
IN ORGANIZATION. THIS SYSTEM HAS THE POTENTIAL TO BECOME A
TROPICAL DEPRESSION AT ANY TIME DURING THE NEXT DAY OR TWO AS IT
MOVES AWAY FROM HISPANIOLA.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 32W/33W S OF 19N MOVING W NEAR 10 KT.
WAVE REMAINS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE
AS INDICATED BY MIMIC TPW ANIMATION. WAVE IS VERY BROAD COVERING
THE AREA BETWEEN 26W-39W. ANY CONVECTION IS ASSOCIATED WITH THE
ITCZ.

TROPICAL WAVE IS ALONG 49W S OF 15N MOVING W 10-15 KT. WAVE IS
LOW AMPLITUDE AND MOSTLY EMBEDDED WITHIN THE ITCZ. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE WITHIN 180 NM EITHER SIDE OF
THE WAVE AXIS N OF THE ITCZ.

TROPICAL WAVE IS ALONG 70W S OF 16N MOVING W 10-15 KT. THIS WAVE
REMAINS SOMEWHAT DIFFICULT TO LOCATE DUE TO THE CLOSE PROXIMITY
OF THE LOW PRESSURE SYSTEM DESCRIBED IN THE SPECIAL FEATURES
SECTION AND THE CURRENT POSITION IS BASED ON SURFACE
OBSERVATIONS. NO ASSOCIATED SHOWERS/CONVECTION.

TROPICAL WAVE IS ALONG 84W S OF 18N MOVING W NEAR 15 KT. WELL
DEFINED INVERTED-V CURVATURE IS OBSERVED IN THE LOW CLOUDS ON
SATELLITE IMAGERY. NO ASSOCIATED SHOWERS/CONVECTION IS NOTED.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N14W 14N30W 11N38W 9N52W 10N62W.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 7N-13N
BETWEEN 33W-45W AND WITHIN 75 NM ALONG THE COAST OF LIBERIA
BETWEEN 8W-11W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 12N-15N BETWEEN 26W-35W. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE FROM 2N-8N BETWEEN 27W-42W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH THAT COVERS THE E US EXTENDS S TO OVER THE NE
GULF E OF THE MISSISSIPPI VALLEY BRINGING DRY STABLE AIR TO THE
GULF WATERS N OF 29N E OF 92W ACROSS THE N FLORIDA PENINSULA. A
BROAD UPPER RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED OVER
CENTRAL MEXICO WITH THE AXIS EXTENDING E TO OVER S FLORIDA AND
FLORIDA STRAITS. A SURFACE TROUGH IS BENEATH THIS UPPER RIDGE
EXTENDING FROM BROWNSVILLE TEXAS TO THE BAY OF CAMPECHE NEAR
19N95W. UPPER DIFFLUENCE IS GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS OVER THE W GULF S OF 28N W OF 92W WITH
SCATTERED SHOWERS OVER THE E GULF FROM 24N-28N E OF 88W ACROSS S
FLORIDA AND THE FLORIDA KEYS.

CARIBBEAN SEA...
THE MAIN CONCERN FOR THE NEXT FEW DAYS CONTINUES TO BE THE AREA
OF LOW PRESSURE DESCRIBED IN THE SPECIAL FEATURES SECTION. THE
UPPER RIDGE FROM THE GULF OF MEXICO COVERS THE NW CARIBBEAN W OF
84W AND AN UPPER TROUGH FROM THE W ATLC EXTENDS ACROSS CUBA...
THE CAYMAN ISLANDS AND JAMAICA N OF 16N BETWEEN 75W-84W. ALL
THIS IS PROVIDING UPPER LEVEL DIFFLUENCE TO GENERATE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 15N-21N W OF 75W TO INLAND
OVER THE YUCATAN PENINSULA. THE UPPER RIDGE ASSOCIATED WITH THE
LOW PRESSURE SYSTEM IN THE SPECIAL FEATURES COVERS THE E
CARIBBEAN E OF 73W WITH THE AXIS EXTENDING FROM NW VENEZUELA
ACROSS THE ABC ISLANDS ENCOMPASSING THE LESSER ANTILLES TO
HISPANIOLA AND ENHANCING THE ACTIVITY ASSOCIATED THERE AS WELL
AS SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 15N TO INLAND
OVER SOUTH AMERICA BETWEEN 71W-74W AND S OF 12N W OF 74W TO
INLAND OVER CENTRAL AMERICA.

ATLANTIC OCEAN...
A DEVELOPING CONCERN IS THE ACTIVITY ASSOCIATED WITH THE LOW
PRESSURE AREA DESCRIBED IN THE SPECIAL FEATURES ABOVE AS THE LOW
MOVES INTO THE SW ATLC WATERS. THE UPPER TROUGH OVER THE E US IS
PUSHING E INTO THE W ATLC N OF 29N W OF 77W. A NARROW UPPER
RIDGE EXTENDS FROM THE N BAHAMA ISLANDS NEAR 26N78W TO BEYOND
32N72W PROVIDING UPPER LEVEL DIFFLUENCE TO GENERATE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 150/180 NM W OF SURFACE
TROUGH THAT EXTENDS FROM BEYOND 32N74W TO OVER FLORIDA NEAR PALM
BEACH TO JUST S OF LAKE OKEECHOBEE. AN UPPER TROUGH IS TO THE E
EXTENDING FROM AN UPPER LOW NEAR 30N65W TO ACROSS CUBA AND INTO
THE NW CARIBBEAN. DRY STABLE AIR COVERS THIS SAME AREA LEAVING
THE REMAINDER OF THE W ATLC CLEAR THIS MORNING. THE UPPER RIDGE
ASSOCIATED WITH THE LOW PRESSURE SYSTEM IN THE SPECIAL FEATURES
EXTENDS FROM 22N61W SW INTO THE CARIBBEAN ACROSS THE VIRGIN
ISLANDS COVERING THE AREA BETWEEN HISPANIOLA AND THE LESSER
ANTILLES ENHANCING THE ACTIVITY ASSOCIATED THERE. A CUT-OFF
UPPER LOW IS IN THE CENTRAL ATLC NEAR 23N48W GENERATING ISOLATED
SHOWERS FROM 22N-28N BETWEEN 46W-53W. A DEEP LAYERED LOW IS IN
THE E ATLC N OF 24N BETWEEN 18W-35W WITH THE UPPER LOW NEAR
32N27W AND THE SURFACE LOW NEAR 31N27W WITH A SURFACE TROUGH
EXTENDING SW TO 27N32W GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS N OF 28N BETWEEN 21W-29W. THE TYPICAL E/W
UPPER RIDGE THAT EXTENDS FROM AFRICA TO 43W ALONG 15N HAS BEEN
SUPPRESSED TO THE S DUE TO THE UPPER TROUGH MENTIONED ABOVE. THE
SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC N OF 23N BETWEEN
37W-58W WITH A 1021 MB HIGH E OF BERMUDA NEAR 33N58W.

$$
WALLACE





This weather bulletin was brought to you by:
www.nashvilleweather.net