[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUN 27 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
1715 UTC.

...TROPICAL WAVES...
A WEAK TROPICAL WAVE IS ALONG 25W S OF 14N MOVING W AT 20 KT.
THE SCATTERED MODERATE CONVECTION THAT WAS ACCOMPANYING THE WAVE
EARLIER IS WANING SIGNIFICANTLY...BUT THERE REMAINS A REGION OF
MORE ORGANIZED CONVECTION AROUND 25W BETWEEN 2N AND 4N.

A TROPICAL WAVE ALONG 37W S OF 12N IS MOVING W AT 15-20 KT. A
BROAD MID TO LOW LEVEL CIRCULATION IS NOTED ON INFRARED
SATELLITE IMAGERY AND WIDESPREAD DEEP CONVECTION CAN BE FOUND E
OF THE WAVE IN THE REGION WITHIN 11N34W TO 6N29W.

A TROPICAL WAVE HAS BEEN ADDED ALONG 50W S OF 13N.  THE LACK OF
DEEP CONVECTION WITH THIS WAVE HAS MADE IT DIFFICULT TO TRACK...
BUT THE WAVE WAS IDENTIFIED BASED ON AN EVIDENT LOW LEVEL
CIRCULATION NOTED ON VISIBLE SATELLITE IMAGERY CENTERED AROUND
9N50W IN ADDITION TO THE ASCAT PASS AROUND 1240Z THAT SHOWED A
DISTINCT TURNING IN THE WIND FIELD IN ADVANCE 0F THE WAVE.  THE
FEATURE COULD BE TRACKED BACK ON THE HOVMOLLER DIAGRAM FROM
1145Z/25 THROUGH 1145Z THIS MORNING.  IN ADDITION...THE CIMSS
MIMIC-TPW PRODUCT ALSO SHOWS A DISTINCT NORTHWARD SURGE IN
ATMOSPHERIC MOISTURE WITH THIS WAVE.  THE INITIAL ESTIMATE OF
THE FORWARD MOTION IS W AT 15 KT.

A WEAK TROPICAL WAVE APPEARS TO HAVE PASSED THROUGH TRINIDAD AND
TOBAGO THIS EVENING ACCORDING TO SFC OBS.  THE WAVE LIES MAINLY
S OF 13 BETWEEN 61W AND 62W AND IS MOVING W AT 20 KT.
CONVECTION WITH THIS WAVE IS WIDELY SCATTERED AND LIES PRIMARILY
OFF THE NORTHEASTERN VENEZUELA COAST BETWEEN CARACAS AND GRENADA.

A TROPICAL WAVE ALONG 91W S OF 22N HAS MOVED THROUGH THE
YUCATAN PENINSULA AND NOW LIES MAINLY IN THE EASTERN PACIFIC
OCEAN.  HOWEVER...SIGNIFICANT CONVECTION ASSOCIATED WITH THE
WAVE CAN BE FOUND IN THE CENTRAL GULF OF MEXICO BETWEEN 27N95W
AND 24N87W AS WELL AS OFF THE NORTHERN YUCATAN PENINSULA S OF
23N.  PLEASE SEE THE EASTERN PACIFIC TROPICAL WEATHER
DISCUSSION...TWDEP...FOR FURTHER DETAILS ON THIS WAVE.


...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 10N16W 10N22W 8N35W 5N42W AND
INTO NORTHEASTERN SOUTH AMERICA NEAR 4N51W. IN ADDITION TO
CONVECTION ASSOCIATED WITH TROPICAL WAVES...SCATTERED MODERATE
TO STRONG CONVECTION IS MOVING OFF THE WEST AFRICAN COAST TO 19W
FROM 9N-14N. SCATTERED MODERATE CONVECTION CAN BE FOUND OFF THE
NORTHEASTERN BRAZIL COAST S OF THE LINE FROM 3N41W TO
5S29W...WITH MORE VIGOROUS CONVECTION FOUND ON THE EASTERN EDGE
OF THAT REGION SE AND S OF ILHA FERNANDO DE NORONHA.


...DISCUSSION...

GULF OF MEXICO...
A HIGHLY AMPLIFIED UPPER PATTERN OVER THE GULF OF MEXICO IS
MARKED BY A LOW OVER THE WESTERN GULF AND A RIDGE OVER THE
EASTERN GULF.  AT THE SURFACE...THE WESTERN EDGE OF THE CENTRAL
NORTH ATLC RIDGE EXTENDS INTO THE EASTERN GULF WHILE A LOW
PRESSURE TROUGH MOVING INTO THE SOUTHERN PLAINS IS INDUCING
SOUTHEASTERLY GULF RETURN FLOW INTO THE TEXAS COAST.  AS A
RESULT...DEEP SOUTHERLY FLOW DOMINATES THE CENTRAL GULF AND IS
HELPING TO SUPPLY MOISTURE...IN CONJUNCTION WITH THE NORTHERN
EDGE OF THE TROPICAL WAVE PASSING THROUGH SOUTHERN MEXICO...TO
THE DEEP CONVECTION FOUND IN THE CENTRAL GULF BETWEEN 27N95W AND
24N87W AS WELL AS OFF THE NORTHERN YUCATAN PENINSULA S OF 23N.
THE MOST ORGANIZED AND VIGOROUS CONVECTION CAN BE FOUND WITHIN
THE REGION OF UPPER LEVEL DIVERGENT FLOW IN THE GULF FOUND
BETWEEN 85W AND 90W.  ELSEWHERE...ISOLATED THUNDERSTORMS CAN BE
FOUND NEAR THE CENTRAL GULF COAST BETWEEN BILOXI...MISSISSIPPI
AND APALACHICOLA...FLORIDA.

CARIBBEAN...
STRONG EASTERLY TRADE WINDS ON THE SOUTHERN EDGE OF THE
SUBTROPICAL RIDGE CENTERED ALONG 28N DOMINATES THE LOW LEVEL
PATTERN IN THE CARIBBEAN.  RELATIVELY DRY CONDITIONS AND UPPER
LEVEL CONVERGENCE OVER THE CENTRAL CARIBBEAN ARE SUPPRESSING
CONVECTION OVER MUCH OF THE REGION.  THE TROPICAL WAVE BETWEEN
61W AND 62W IS GENERATING LITTLE SENSIBLE WEATHER...WITH ONLY
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS PRIMARILY OFF THE
NORTHEASTERN VENEZUELA COAST BETWEEN CARACAS AND GRENADA.  MORE
VIGOROUS CONVECTION CAN BE FOUND IN THE FAR SOUTHEASTERN
CARIBBEAN OFF THE SOUTHERN COSTA RICA AND PANAMANIAN COAST WHERE
DEEP MOISTURE IS MORE PLENTIFUL AND SPEED DIVERGENCE ALOFT IS
INITIATING LIFT.  UNORGANIZED...SCATTERED CONVECTION CAN ALSO BE
FOUND OFF THE SOUTHEASTERN JAMAICAN COAST AND WITHIN THE JAMAICA
CHANNEL EXTENDING NORTHWARD TO THE SOUTHEASTERN CUBAN COAST.

ATLANTIC...
THE SUBTROPICAL HIGH PRESSURE AT THE SURFACE CONTINUES TO
DOMINATE THE LOW LEVEL FLOW ACROSS THE ATLC...WITH EASTERLY
TRADE WINDS FOUND NORTH AND WEST OF 10N30W AND FLOW GENERALLY
TURNING MORE N TO NE TO THE EAST OF THIS LOCATION.  OFF THE
WESTERN AFRICAN COAST...SCATTERED MODERATE TO STRONG CONVECTION
IS MOVING OFFSHORE TO 19W FROM 9N-14N.  TO THE EAST...TWO
TROPICAL WAVES ARE EMBEDDED WITHIN THE ITCZ...ONE AT 26W AND
ANOTHER AT 37W.  THE BEST DIVERGENCE ALOFT LIES BETWEEN THE TWO
WAVES NEAR 31N...WITH AN AREA OF MODERATE CONVECTION FOUND IN
THE REGION WITHIN 11N34W TO 6N29W.  FARTHER EAST...ANOTHER
TROPICAL WAVE INTRODUCED ALONG 50W IS GENERATING LITTLE
CONVECTION.  ELSEWHERE...SCATTERED MODERATE CONVECTION CAN BE
FOUND OFF THE NORTHEASTERN BRAZIL COAST S OF THE LINE FROM 3N41W
TO 5S29W...WITH MORE VIGOROUS CONVECTION FOUND ON THE EASTERN
EDGE OF THAT REGION SE AND S OF ILHA FERNANDO DE NORONHA.
ANOTHER AREA OF MODERATE CONVECTION CAN BE FOUND BETWEEN THE
TROPICAL WAVES AT 50W AND 61-62W WITHIN THE DIVERGENT FLOW
BETWEEN THE UPPER LEVEL CYCLONE AT 23N66W AND THE UPPER LEVEL
ANTICYCLONE NEAR 14N50W.  OFF THE EASTERN FLORIDA COAST...LOOK
FOR AFTERNOON THUNDERSTORMS BEING STEERED EASTWARD OFF THE
PENINSULA TO WEAKEN AS THEY PASS OFFSHORE AROUND SAINT AUGUSTINE
AND FORT PIERCE.

$$
SCHAUER CLARK




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