[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241759
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 24 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A NEW TROPICAL TROPICAL WAVE IS ADDED TO THE 1200 UTC SURFACE
MAP ALONG 22W/23W BASED ON SATELLITE IMAGERY AND THE HOVMOLLER
DIAGRAM THAT SHOWS THE WESTWARD PROPAGATION OF THE WAVE. IN
ADDITION...THE WAVE SHOWS UP WELL ON THE UW-CIMSS TPW PRODUCT
AND 850 MB VORTICITY. THIS SYSTEM MOVED OUT OF AFRICA
YESTERDAY...AND NOW IS APPROACHING THE CAPE VERDE ISLANDS.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 4N-10N
BETWEEN 21W-25W.

TROPICAL WAVE IS ALONG 32W/33W MOVING W NEAR 10 KT. THIS WAVE
ALSO SHOWS UP WELL ON THE MIMIC-TPW PRODUCT AND 850 MB VORTICITY
WITH MOST OF THE CONVECTIVE ACTIVITY EAST OF THE WAVE AXIS.
SCATTERED MODERATE CONVECTION IS FROM 6N-12N BETWEEN 28W-32W.

TROPICAL WAVE IS ALONG 66W MOVING W 5-10 KT. NO DEEP CONVECTION
IS ASSOCIATED WITH THE WAVE.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 8N26W 7N40W 8N60W. BESIDES FOR
THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED
MODERATE CONVECTION IS FROM 4N-7N BETWEEN 10W-15W...AND WITHIN
100 NM SOUTH OF AXIS 35W-40W.

DISCUSSION...

GULF OF MEXICO...
A COLD FRONT CONTINUES TO PUSH E ACROSS THE E GULF AND THE FAR
WEST CARIBBEAN BUT IS LOSING MUCH OF ITS PUNCH AND SPEED. AS OF
1500 UTC...THE FRONT EXTENDS FROM A 1007 MB LOW OVER NORTH
CAROLINA TO 31N81W THEN ACROSS FLORIDA CROSSING THE TAMPA BAY
AREA AND CONTINUING OVER THE SE GULF INTO THE WEST CARIBBEAN TO
THE GULF OF HONDURAS. MOSAIC DOPPLER RADAR FROM THE SE U.S.
DEPICTS A BAND OF SHOWERS WITH EMBEDDED TSTMS AFFECTING THE
WESTERN COAST OF FLORIDA BETWEEN TAMPA BAY AND FORT MYERS.
SHOWERS AND TSTMS ARE ALSO SEEN OVER SE FLORIDA IN A HUMID AND
UNSTABLE ATMOSPHERE AHEAD OF THE FRONT. DEEP LAYERED TROUGH
ASSOCIATED WITH THE FRONT EXTENDS FROM AN UPPER LOW OVER THE
LOWER MISSISSIPPI VALLEY INTO THE GULF AND NE MEXICO. THE STRONG
WINDS THAT HAVE BEEN BLOWING BEHIND THE FRONT ARE EXPECTED TO
DIMINISHED LATE THIS AFTERNOON AND TONIGHT. AN EARLIER QUIKSCAT
PASS SHOWED NLY WINDS OF 25 TO 35 KT JUST BEHIND THE FRONT. DRY
STABLE CONTINENTAL AIR CONTINUES TO PUSH E OVER THE NW PORTION
OF THE GULF CLEARING SKIES FROM SE LOUISIANA TO NEAR JALAPA
MEXICO. THE FRONT WILL CONTINUE TO MOVE SLOWLY THIS AFTERNOON
THEN STALL ACROSS FLORIDA AND THE STRAITS OF FLORIDA TONIGHT AND
THU.

CARIBBEAN SEA...
AN AREA OF DISTURBED WEATHER...ANALYZED 1009 MB SFC LOW...IS
LOCATED OVER THE CARIBBEAN SEA BETWEEN COLOMBIA AND JAMAICA.
SATELLITE IMAGERY SHOWS THE CLOUD PATTERN EXHIBITING CYCLONIC
CIRCULATION DUE TO THE PRESENCE OF THE LOW PRESSURE. CLUSTERS OF
MODERATE TO STRONG CONVECTION ARE OVER THE CENTRAL CARIBBEAN
SOUTH OF JAMAICA. THERE ARE CURRENTLY NO SIGNS OF ORGANIZATION
BUT UPPER-LEVEL ARE FORECAST TO SLOWLY BECOME A LITTLE MORE
FAVORABLE FOR DEVELOPMENT DURING THE NEXT COUPLE OF DAYS.
SCATTERED SHOWERS AND TSTMS ARE OVER THE NW CARIBBEAN JUST AHEAD
OF THE AFOREMENTIONED COLD FRONT. THE FRONT IS EXPECTED TO PUSH
SLOWLY EWD THIS AFTERNOON AND NW WINDS WILL INCREASE TO 20-25 KT
TONIGHT BEHIND THE FRONTAL BOUNDARY TONIGHT. UPPER DIFFLUENCE
BETWEEN AN UPPER LOW LOCATED OVER HONDURAS AND A RIDGE EXTENDING
NW FROM NORTHERN SOUTH AMERICA ACROSS THE CENTRAL CARIBBEAN INTO
E CUBA IS HELPING TO INDUCE ALL THE CONVECTIVE ACTIVITY OBSERVED
IN THE CENTRAL AND WESTERN CARIBBEAN SEA. A WEAK AREA OF LOW
PRESSURE...ANALYZED 1010 MB SFC LOW...IS JUST EAST OF THE
NORTHERN LEEWARD ISLANDS NEAR 17N60W. THIS FEATURE IS PRODUCING
A LARGE AREA OF CLOUDINESS AND SHOWERS. WHILE THIS SYSTEM HAS A
WELL-DEFINED LOW-LEVEL CIRCULATION...SHOWERS AND THUNDERSTORMS
REMAIN POORLY ORGANIZED AND PRIMARILY DISPLACED TO THE EAST DUE
TO STRONG UPPER WLY WINDS OVER THE AREA. UPPER-LEVEL WINDS ARE
EXPECTED TO REMAIN UNFAVORABLE FOR SIGNIFICANT DEVELOPMENT OF
THIS SYSTEM AS IT MOVE SLOWLY WESTWARD DURING THE NEXT COUPLE OF
DAYS. A TROPICAL WAVE IS MOVING ACROSS THE E CARIBBEAN. SEE
TROPICAL WAVE SECTION FOR DETAILS. LIGHT TRADES PREVAIL ACROSS
THE BASIN.

ATLANTIC OCEAN...
BROAD UPPER HIGH SITUATED N OF AREA CLIPS THE W-CENTRAL ATLC
WITH ELY WINDS AND DRY STABLE AIR N OF 26N FROM 55W TO 65W. AN
UPPER LOW IS NE OF THE VIRGIN ISLANDS NEAR 21N62W. AN UPPER
TROUGH EXTENDS NW FROM THIS LOW TO JUST N OF THE NW BAHAMAS. THE
RIDGE THAT DOMINATES THE CARIBBEAN SEA ALSO ENVELOPS EASTERN
CUBA...HISPANIOLA AND THE BAHAMAS. A LARGE DEEP LAYERED TROUGH
COVERS THE E/CENTRAL ATLC WITH A 1002 MB SURFACE LOW CENTERED
NEAR 32N33W AND A SURFACE TROUGH EXTENDING S TO 22N40W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WELL E OF THIS
SYSTEM. A BAND OF TRANSVERSE HIGH CLOUDS ASSOCIATED WITH A JET
STREAM BRANCH WITH CORE WINDS UP TO 70 KT CROSSES THE E-CENTRAL
ATLC ALONG 20N50W 24N35W 23N26W. WEAK UPPER RIDGE EXTENDS ALONG
THE COAST OF W AFRICA N OF 15N ACROSS THE CANARY ISLANDS TO
BEYOND 32N20W COVERING THE REMAINDER OF THE E ATLC. A SFC RIDGE
ANCHORED BY A 1024 HIGH LOCATED N OF AREA NEAR 34N58W DOMINATES
MOST OF THE W AND CENTRAL ATLC. WEAK SFC RIDGE COVERS THE E ATLC
WITH A 1017 HIGH LOCATED NEAR 25N22W. IN BETWEEN...IS THE ABOVE
MENTIONED SFC LOW.

$$
GR




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