[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250547
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI SEP 25 2009

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 29W/30W S OF 19N WITH A 1010 MB LOW ON
THE WAVE NEAR 13N MOVING W 20-25 KT. WAVE IS ALONG THE LEADING
EDGE OF A MOISTURE MAXIMUM AS INDICATED BY THE TOTAL
PRECIPITABLE WATER IMAGERY WITH SAHARAN DUST TO THE N AND BEING
DRAWN INTO THE SURFACE LOW. SCATTERED MODERATE WITH EMBEDDED
CLUSTERS OF ISOLATED STRONG CONVECTION ARE FROM 13N-17N BETWEEN
27W-30W AND FROM 12N-15N BETWEEN 30W-34W.

TROPICAL WAVE IS ALONG 58W S OF 19N MOVING W 20-25 KT. WAVE IS
ALONG W EDGE OF AN UPPER RIDGE DRAWING UPPER LEVEL MOISTURE N
AWAY FROM THE WAVE. CLUSTERS OF SCATTERED MODERATE CONVECTION
ARE FROM 10N-14N BETWEEN 49W AND THE WAVE AXIS.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 11N15W 13N28W 9N40W 10N62W.
LARGE AREA OF NUMEROUS STRONG CONVECTION IS JUST INLAND OVER W
AFRICA WITH SCATTERED/NUMEROUS STRONG CONVECTION WITHIN 120 NM
ALONG THE COAST OF SIERRA LEONE TO JUST S OF DAKAR SENEGAL AND
SCATTERED STRONG CONVECTION FROM 5N-8N BETWEEN 15W-17W. SMALL
CLUSTERS OF ISOLATED MODERATE CONVECTION DOT THE REMAINDER OF
THE ITCZ FROM 5N-11N BETWEEN 24W-51W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT ENTERS THE GULF OVER LOUISIANA NEAR VERMILION
BAY CONTINUING S ALONG 27N95W INTO THE BAY OF CAMPECHE AND S
MEXICO TO NEAR 18N96W. A WEAK SURFACE TROUGH IS IN THE E BAY OF
CAMPECHE FROM 23N90W TO W GUATEMALA NEAR 15N92W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE W OF THE FRONT WITH CLUSTERS
OF SIMILAR ACTIVITY OVER THE REMAINDER OF THE BAY OF CAMPECHE S
OF 21N BETWEEN THE FRONT AND SURFACE TROUGH. BROAD UPPER RIDGE
ANCHORED OVER THE NE GULF JUST OFF SHORE OF PENSACOLA FLORIDA
EXTENDS AN AXIS SW TO TAMPICO MEXICO FORCING AFTERNOON
THUNDERSTORMS THAT DEVELOPED OVER THE FLORIDA PENINSULA INTO THE
GULF WATERS LEAVING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 120 NM
ALONG THE W COAST OF FLORIDA. SIMILAR SHOWERS/THUNDERSTORMS THAT
DEVELOPED OVER W CUBA ARE WITHIN 60 NM OF OF THE NW COAST OF
CUBA. OTHERWISE...THE REMAINDER OF THE GULF IS TRANQUIL TONIGHT.

CARIBBEAN SEA...
AN UPPER RIDGE IS OVER THE W CARIBBEAN EXTENDING THE AXIS FROM
PANAMA TO THE NE YUCATAN PENINSULA PROVIDING DIFFLUENCE ALOFT TO
GENERATE SCATTERED SHOWERS/THUNDERSTORMS W OF A LINE FROM PANAMA
NEAR 9N79W 15N80W TO 21N85W INCLUDING MOST OF CENTRAL AMERICA.
BROAD UPPER TROUGH OVER THE W/CENTRAL ATLC EXTENDS OVER THE NE
CARIBBEAN N OF 17N FROM THE VIRGIN ISLANDS TO CENTRAL CUBA
PRODUCING ISOLATED SHOWERS OVER THE ISLANDS FROM PUERTO RICO TO
THE WINDWARD PASSAGE. FRESH TO STRONG EASTERLY TRADE WINDS
CONTINUE ACROSS THE AREA BUT THE E CARIBBEAN REMAINS RATHER
CLEAR TONIGHT INCLUDING THE LESSER ANTILLES.

ATLANTIC OCEAN...
BROAD UPPER RIDGE ANCHORED IN THE NE GULF OF MEXICO COVERS THE W
ATLC AND COMBINED WITH AN UPPER TROUGH OVER THE W/CENTRAL ATLC
CENTERED NEAR 28N64W IS PRODUCING STRONG NE UPPER WINDS OVER THE
W ATLC W OF 68W. THE UPPER TROUGH IS SUPPORTING A SURFACE TROUGH
THAT EXTENDS FROM 33N63W THROUGH A 1012 MB LOW NEAR 28N66W TO
24N67W. THE UPPER LOW IS ALSO PRODUCING CLUSTERS OF ISOLATED
SHOWERS AND POSSIBLE THUNDERSTORMS FROM 19N-23N BETWEEN 61W-70W
AND WITHIN 120/150 NM OF LINE FROM 26N55W 32N59W TO 32N64W. A
PAIR OF WEAK SURFACE TROUGHS ARE ANALYZED FROM 32N44W TO 29N50W
AND FROM 26N55W TO 22N57W WITH AN AREA OF SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS BETWEEN THEM FROM 22N-29N
BETWEEN 49W-54W. THE REMAINDER OF THE ATLC IS DOMINATED BY A
SURFACE RIDGE THAT COVERS THE AREA N OF 20N W OF 45W AND
RESULTING IN FAIR WEATHER FOR THE E ATLC. THE LAST VISIBLE
SATELLITE IMAGES SHOW A SWATH OF SAHARAN DUST WITHIN 200/225 NM
OF LINE FROM WESTERN SAHARA NEAR SW TO THE W OF THE TROPICAL
WAVE TO NEAR 40W AND BEING DRAWN BACK INTO THE LOW ASSOCIATED
WITH THE TROPICAL WAVE.

$$
WALLACE






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