[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221026
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON SEP 22 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 COVERS THE AREA WITH A 1008 MB LOW
ANALYZED JUST N OF THE MONA PASSAGE. THIS SYSTEM STILL DOES NOT
HAVE A WELL DEFINED CENTER WITH MULTIPLE ROTATIONS OBSERVED ON
PUERTO RICO RADAR EMBEDDED WITHIN AN AREA OF HEAVY SHOWERS AND
BANDS OF THUNDERSTORMS FROM 15N-20N BETWEEN 65W-68W INCLUDING
PUERTO RICO AND THE VIRGIN ISLANDS. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 14N-21N BETWEEN 63W-69W ENHANCED BY UPPER
LEVEL DIFFLUENCE. UPPER-LEVEL WINDS ARE FORECAST TO BECOME A
LITTLE MORE FAVORABLE FOR DEVELOPMENT...AND THE SYSTEM COULD
BECOME A TROPICAL DEPRESSION LATER TODAY AS IT MOVES SLOWLY
NORTH OR NORTH-NORTHWESTWARD DURING THE NEXT COUPLE OF DAYS.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 27W/28W OF 17N MOVING W NEAR 10 KT. WAVE
IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE AS
INDICATED BY MIMIC TPW ANIMATION BUT LACKS ANY WELL DEFINED
ROTATION IN EITHER THE LOW OR MID LEVELS. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 12N-16N BETWEEN
24W-30W.

TROPICAL WAVE IS ALONG 42W/43W FROM 12N-20N MOVING W NEAR 10 KT.
THIS WAVE REMAINS WEAK AND ILL-DEFINED. WAVE IS EMBEDDED WITHIN
DRY STABLE AIR...THUS NO ASSOCIATED SHOWERS/CONVECTION.

TROPICAL WAVE IS ALONG 62W/63W S OF 21N MOVING W 10-15 KT. THIS
WAVE IS MOVING INTO THE AREA OF THE BROAD LOW PRESSURE DESCRIBED
IN THE SPECIAL FEATURES WITH NO ASSOCIATED SHOWERS/CONVECTION.

TROPICAL WAVE IS ALONG 71W S OF 18N MOVING NEAR 10 KT. THIS WAVE
IS JUST TO THE W OF THE LOW PRESSURE AREA DESCRIBED IN THE
SPECIAL FEATURES. WEAK INVERTED-V CURVATURE IS OBSERVED ON
INFRARED SATELLITE IMAGERY WITH A SMALL AREA OF ISOLATED STRONG
CONVECTION WITHIN A 30 NM RADIUS OF 17N71W.

TROPICAL WAVE IS ALONG 89W S OF 21N MOVING W NEAR 10 KT. THIS
WAVE IS INLAND OVER THE YUCATAN PENINSULA AND INTO THE E PACIFIC
REGION WITH SCATTERED SHOWERS.ISOLATED THUNDERSTORMS MOSTLY
INLAND OVER CENTRAL AMERICA/E PACIFIC REGION AND ALONG THE
IMMEDIATE COAST OF S BELIZE.

...THE ITCZ...
ITCZ AXIS IS ANALYZED ALONG 8N12W 11N29W 6N41W 8N52W 8N60W.
SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF STRONG CONVECTION
ARE FROM 4N-9N BETWEEN 38W-47W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS WITHIN 45 NM OF LINE FROM 12N36W TO 9N39W.
SCATTERED CLUSTERS OF SCATTERED MODERATE CONVECTION DOT THE AREA
FROM 3N-11N BETWEEN 29W-50W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH OVER THE E US EXTENDS ACROSS THE NW GULF
BRINGING DRY STABLE AIR TO THE AREA N OF A LINE FROM THE
FLORIDA/ALABAMA BORDER TO TEXAS JUST N OF BROWNSVILLE. AN UPPER
RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED OVER S/CENTRAL
MEXICO EXTENDING ACROSS THE GULF AND S FLORIDA INTO THE W ATLC.
A SURFACE TROUGH REMAINS OVER THE W GULF EXTENDING FROM 27N95W
THROUGH THE BAY OF CAMPECHE TO S MEXICO NEAR 18N94W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 27N W OF 93W AND FROM
23N-25N BETWEEN 87W-93W...ALL ENHANCED BY UPPER LEVEL
DIFFLUENCE. ISOLATED SHOWERS ARE OVER THE NE GULF N OF 26N E OF
88W.

CARIBBEAN SEA...
THE MAIN CONCERN FOR THE NEXT FEW DAYS IS THE AREA OF LOW
PRESSURE DESCRIBED IN THE SPECIAL FEATURES ABOVE. AN UPPER
TROUGH EXTENDS FROM CENTRAL CUBA AND THE CAYMAN ISLANDS SW TO
THE GULF OF HONDURAS BOUNDED BY THE UPPER RIDGE OVER THE GULF OF
MEXICO TO THE W AND TO THE E BY AN UPPER RIDGE ANCHORED IN THE
CENTRAL CARIBBEAN NEAR 15N75W. UPPER LEVEL DIFFLUENCE IS
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 10N-18N
BETWEEN 80W-95W BUT IS REMAINING OFFSHORE OF NICARAGUA AND
HONDURAS. AN UPPER HIGH ASSOCIATED WITH THE AREA IN THE SPECIAL
FEATURES IS LOCATED NEAR THE VIRGIN ISLANDS AND IS ELONGATED
FROM THE CENTRAL ATLC NEAR 23N59W SW TO 13N69W ENHANCING THE
ACTIVITY IN THE SPECIAL FEATURES. OTHERWISE THE REMAINDER OF THE
CARIBBEAN REMAINS RATHER CLEAR THIS MORNING WITH THE EXCEPTION
OF POSSIBLE ISOLATED SHOWERS FROM 11N-17N BETWEEN 73W-80W.

ATLANTIC OCEAN...
WEAK UPPER TROUGH EXTENDS FROM THE W ATLC NEAR 26N72W INTO THE
CARIBBEAN ACROSS CENTRAL CUBA BOUNDED TO THE W BY THE UPPER
RIDGE THAT COVERS THE GULF OF MEXICO. A SURFACE TROUGH ENTERS
THE W ATLC THROUGH 32N78W SW TO OVER FLORIDA NEAR MELBOURNE TO
LAKE OKEECHOBEE GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS NW OF THE TROUGH TO INLAND OVER THE SE US AND N OF
30N W OF 73W. AN UPPER RIDGE IS IN THE CENTRAL ATLC ANCHORED N
OF THE REGION COVERING THE AREA N OF 28N FROM 48W-65W PROVIDING
UPPER LEVEL DIFFLUENCE TO GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 27N-31N BETWEEN 62W-65W. A RATHER BENIGN
UPPER LOW IS ALSO IN THE CENTRAL ATLC NEAR 23N48W AND IS
EMBEDDED IN DRY STABLE AIR. THE TYPICAL E/W UPPER RIDGE COVERS
THE E ATLC ALONG 15W EXTENDING FROM AFRICA TO NEAR 40W GIVING
THE E SUBTROPICAL ATLC NEAR ZONAL WESTERLY FLOW. THE SURFACE OF
THE ATLC IS DOMINATED BY A RIDGE E OF THE SURFACE TROUGH IN THE
W ATLC ANCHORED BY A 1025 MB HIGH NEAR 34N52W AND A WEAK 1018 MB
HIGH IN THE E ATLC NEAR 27N30W.

$$
WALLACE





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