[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 090000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 08 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
A LOW AMPLITUDE TROPICAL WAVE IS ALONG 31/32W S OF 16N MOVING W
AROUND 15 KT. 850 MB SATELLITE DERIVED VORTICITY AND THE
MIMIC-TPW FROM CIMSS SUPPORT THE WAVE POSITION. A CYCLONIC
TURNING IS SEEN ALONG THE WAVE AXIS NEAR 11N. SCATTERED MODERATE
CONVECTION IS MAINLY AHEAD OF THE WAVE AND NEAR THE INTERSECTION
OF THE WAVE AND THE ITCZ FROM 6N-10N BETWEEN 32W-40W. SCATTERED
SHOWERS ARE NEAR 11N32W.

A HIGH AMPLITUDE TROPICAL WAVE IS ALONG 52W FROM 11N-25N MOVING
W 15-20 KT. THE WAVE CONTINUES TO SHOW A WELL DEFINED INVERTED-V
CURVATURE ON SATELLITE IMAGERY WITH SCATTERED SHOWERS NEAR THE N
END OF THE WAVE AXIS. THE SSMI-DERIVED TOTAL PRECIPITABLE WATER
INDICATES A BAND OF MOISTURE EXTENDING NORTH-SOUTH ALONG THE
WAVE AXIS.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN ALONG 63W/64W
SOUTH OF 21N MOVING W 15-20 KT. THE INTERACTION OF THE WAVE WITH
AN UPPER-LEVEL LOW LOCATED NE OF THE LEEWARD ISLANDS NEAR 22N60W
IS PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE
LEEWARD/VIRGIN ISLANDS AND E PORTION OF PUERTO RICO. THIS AREA
OF MOISTURE IS FORECAST BY THE COMPUTER MODELS TO MOVE WNW CLOSE
TO NE PUERTO RICO TONIGHT AND SATURDAY. THE WAVE IS ALSO
GENERATING SOME SHOWER ACTIVITY OVER NE VENEZUELA.

A TROPICAL WAVE IS ALONG 83W/84W S OF 21N MOVING W 10-15 KT.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ASSOCIATED WITH
THE WAVE OVER HONDURAS AND THE CARIBBEAN PLAINS OF NICARAGUA AS
WELL AS OVER PARTS OF COSTA RICA AND WESTERN PANAMA WHERE THE
EPAC ITCZ IS ALSO HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS.
BROAD AREA OF DEEP LAYERED MOISTURE IS OBSERVED ON MIMIC-TPW
PRODUCT COVERING THE W CARIBBEAN W OF 80W. THE WAVE REMAINS AT
THE LEADING EDGE OF A SURGE OF AFRICAN DUST THAT COVERS THE
CENTRAL CARIBBEAN TO OVER THE GREATER ANTILLES.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N15W 11N26W 7N40W 8N50W 8N62W. A
LARGE CLUSTER OF MODERATE TO STRONG CONVECTION IS MOVING OFF THE
AFRICAN COAST AN COVERS FROM 10N-13N BETWEEN 13W-17W. THIS
ACTIVITY MAY BE ASSOCIATED WITH A NEW TROPICAL WAVE. SCATTERED
MODERATE CONVECTION IS FROM 8N-10N BETWEEN 25W-29W...AND FROM
6N-10N BETWEEN 30W-40W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS OVER N SURINAME AND SOUTH-CENTRAL GUYANA.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER-LEVEL HIGH OVER THE FOUR CORNER REGION EXTENDS A RIDGE
OVER THE NORTHERN GULF WATERS WHILE A DEEP LAYERED TROUGH
CONTINUES TO DIG SOUTH OVER THE EASTERN U.S. INTO N FLORIDA. THE
ATTENDANT COLD FRONT HAS MOVED INTO SE GEORGIA AND THE FLORIDA
PANHANDLE AT 2100 UTC. THE FRONT WILL MOVE A LITTLE MORE SWD
ACROSS THE N GULF WATERS TONIGHT THEN WILL BEGIN TO DISSIPATE
DURING THE WEEKEND. MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS
AND TSTMS ARE AFFECTING THE GULF REGION N OF 26N AND A GOOD
PORTION OF THE SUNSHINE STATE. A DRY AIR MASS FOLLOWS THE FRONT
AND IS INVADING THE SE CONUS. AN UPPER-LEVEL LOW ROTATING OVER
CENTRAL CUBA CONTINUES TO ENHANCE CONVECTION OVER THE YUCATAN
PENINSULA. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A
RIDGE ANCHORED ON A WEAK 1015 HIGH MB HIGH THAT REMAINS LOCATED
NEAR 27N93W. WINDS ARE MAINLY LIGHT AND VARIABLE ACROSS THE
AREA.

CARIBBEAN SEA...
AS PREVIOUSLY MENTIONED...AN UPPER-LEVEL LOW IS SPINNING OVER
CENTRAL CUBA COVERING THE SE GULF AND THE NW CARIBBEAN. BROAD
UPPER-LEVEL HIGH IS OVER THE CENTRAL CARIBBEAN WITH THE CENTER
NEAR THE ABC ISLANDS. ANOTHER UPPER-LEVEL LOW IS NE OF THE
LEEWARD ISLANDS NEAR 22N60W. THE CYCLONIC FLOW ASSOCIATED WITH
THIS SECOND UPPER LOW ENVELOPS THE FAR E CARIBBEAN. THE
INTERACTION OF THIS LOW WITH A TROPICAL WAVE IS GENERATING SOME
SHOWER ACTIVITY OVER THE NE CARIBBEAN. UPPER LEVEL DIFFLUENCE
COUPLED WITH ANOTHER TROPICAL WAVE IS SUPPORTING THE DEVELOPMENT
OF SCATTERED SHOWERS AND THUNDERSTORMS OVER THE SW CARIBBEAN AND
CENTRAL AMERICA FROM W PANAMA TO HONDURAS. ONCE AGAIN...
CONVECTION HAS FLARED UP OVER CUBA DUE TO THE PRESENCE
OF THE ABOVE MENTIONED UPPER LOW. MODERATE TO STRONG EASTERLY
TRADE WINDS ARE BLOWING ACROSS THE BASIN WITH THE STRONGEST
WINDS...AS USUAL... JUST OFFSHORE THE COLOMBIAN COAST.

ATLANTIC OCEAN...
SEVERAL UPPER-LEVEL LOWS ARE NOTED ACROSS THE DISCUSSION AREA ON
WV IMAGERY. ONE OF THEM IS JUST E OF THE BAHAMAS COVERING THE W
ATLC W OF 70W AND IS PRODUCING AN AREA OF SCATTERED SHOWERS AND
TSTMS FROM 24N-31N BETWEEN 68W-75W. THE SECOND ONE IS NE OF THE
LEEWARD ISLANDS AND THE THIRD ONE REMAINS OVER THE CENTRAL ATLC
NEAR 30N43W. ANOTHER UPPER-LEVEL LOW IS OVER THE E ATLC NEAR
29N23W WITH A TROUGH EXTENDING SW TO ANOTHER UPPER LOW CENTERED
NEAR 21N30W. IN BETWEEN...A PAIR OF UPPER-LEVEL HIGHS. THE MAIN
ONE IS OVER THE TROPICS NEAR 20N44W. OTHERWISE..THE ATLANTIC IS
DOMINATED BY A SURFACE RIDGE EXTENDING SW FROM A 1025 MB HIGH
LOCATED JUST NE OF THE AZORES. TIGHT PRES GRADIENT BETWEEN THE
ATLC RIDGE AND LOWER PRES OVER AFRICA IS PRODUCING A SWATH OF
NELY WINDS OF 20-25 KT BETWEEN THE MADEIRA/CANARY ISLANDS AND
THE AFRICAN COAST. THE ATLC RIDGE WILL STRENGTHEN SLIGHTLY
THROUGH MON...THEN BUILD WWD TUE AND WED. THE FRONTAL BOUNDARY
OVER THE SE U.S. IS FORECAST TO MOVE INTO THE FAR NW PORTION OF
THE AREA LATE TONIGHT/SAT MORNING AND IS EXPECTED TO REMAIN N OF
28N.

$$
GR



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