[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231757
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU AUG 23 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...
LOW AMPLITUDE TROPICAL WAVE IS OVER THE OPEN ATLANTIC ALONG
42W/43W S OF 13N ESTIMATED TO BE MOVING W 10-15 KT. THE LOW
LEVEL CYCLONIC TURNING IN THE VICINITY MAY BE MORE ASSOCIATED
WITH THE ITCZ. HOWEVER...THERE IS A SLIGHTLY HIGHER AMPLITUDE
INVERTED V PATTERN NOTED FURTHER NW FROM 16N-23N BETWEEN
45W-53W...BUT THE EVOLUTION OF THIS FEATURE OVER THE LAST FEW
DAYS IS A LITTLE UNCLEAR AND COULD BE MORE ASSOCIATED WITH LIFT
AHEAD OF THE UPPER LOW NEAR 21N55W. REGARDLESS...NEITHER AREA IS
WELL ORGANIZED AND DEEP CONVECTION REMAINS MINIMAL.

TROPICAL WAVE IS ALONG 65W/66W S OF 20N MOVING W NEAR 20 KT. IT
APPEARS AS IF THE SRN PORTION OF THIS WAVE IS OUTRUNNING THE LOW
LEVEL TURNING WE HAVE BEEN TRACKING FURTHER N. SCATTERED
SHOWERS/ISOLATED TSTMS WITH THIS SRN PORTION HAVE BEEN RACING W
THROUGH THE ABC ISLANDS OVER THE LAST FEW HOURS. THERE REMAINS
TO BE SOME LOW LEVEL CYCLONIC TURNING/TROUGHING NEAR AND JUST NE
OF THE LEEWARD ISLANDS...WHICH WILL LIKELY BE MADE A TROUGH ON
THE 1800 UTC MAP WITH THE SRN PORTION REMAINING A WAVE. ISOLATED
SHOWERS/TSTMS WITH THIS SECTION ARE AFFECTING THE LEEWARD
ISLANDS.

TROPICAL WAVE IS ALONG 80/81W S OF 22N MOVING W 15-20 KT. THE
WAVE APPEARS TO HAVE BECOME DETACHED FROM THE NEWLY FORMED 1014
MB SFC LOW NEAR THE NW BAHAMAS...WHICH HAS MOVED VERY LITTLE
OVER THE LAST SEVERAL HOURS. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE MOVING INTO THE NW CARIBBEAN WITH THE WAVE FROM
15N-22N BETWEEN 77W-85W.

ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N15W 12N27W 10N40W 9N60W. CLUSTERS
OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE ALONG AND
JUST OFFSHORE THE AFRICAN COAST FROM 12N-16N E OF 20W. SOME OF
THIS APPEARS TO BE ASSOCIATED WITH A TROPICAL WAVE THAT RECENTLY
MOVED OFF THE COAST AS PER DAKAR RAOB DATA. SCATTERED MODERATE
IS ALSO WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 50W-62W.

DISCUSSION...

GULF OF MEXICO...
DEAN IS NOW GONE AND THE WINDS AND SEAS ACROSS THE GULF HAVE
MOSTLY SUBSIDED...THOUGH HIS EFFECTS ARE NOT OVER. LONGER PERIOD
SWELL ENERGY FROM THE STORM CONTINUES TO REGISTER AT MANY OF THE
BUOYS ALONG THE GULF COAST. THIS WILL ALSO CONTINUE TO SLOWLY
SUBSIDE THROUGH THE END OF THE WEEK. ISOLATED TSTMS DOT THE ERN
GULF MAINLY S OF 29N E OF 90W...IN A REGION OF DIFFLUENT FLOW
ALOFT BETWEEN AN INVERTED UPPER TROUGH EXTENDING THROUGH THE
REGION AND AN UPPER HIGH OVER THE SOUTHEAST. EXCEPT FOR THE
MOISTURE NOTED IN THE BAY OF CAMPECHE...DRY/STABLE MID TO UPPER
AIR IS OVER THE WRN GULF E OF 90W WITH E TO NE UPPER FLOW. A
WEAK TROPICAL WAVE WILL MOVE INTO THE SE GULF OF MEXICO EARLY
FRI...CROSS THE MIDDLE GULF SAT...AND REACH THE FAR WESTERN GULF
SUN. MEANWHILE...WEAK SFC RIDGING WILL PERSIST ALONG 30N THROUGH
THE WEEKEND.

CARIBBEAN SEA...
A PAIR OF TROPICAL WAVES ARE MOVING THROUGH THE BASIN AND ARE
RESPONSIBLE FOR MOST OF THE WEATHER ACROSS THE BASIN THIS
AFTERNOON. SEE ABOVE FOR MORE DETAILS. THE SHOWERS/TSTMS JUST S
OF CUBA NOTED WITH THE WAVE NEAR 80W ARE ALSO BEING SUPPORTED BY
DIFFLUENCE ALOFT BETWEEN THE INVERTED TROUGHING EXTENDING UP THE
NW CARIB AND RIDGING BUILDING INTO THE CENTRAL CARIB FROM THE
ATLC. OTHERWISE TRADES ARE MODERATE AND GENERALLY EXPECTED TO
PERSIST THROUGH FRI.

ATLANTIC OCEAN...
THE MAIN FEATURE IN THE WRN ATLC IS THE SLOW MOVING...WEAK 1014
MB SFC LOW NEAR THE NRN BAHAMAS. THIS FEATURE HAS BEEN
GENERATING A FEW TSTMS WITHIN 210 NM MAINLY NW QUADRANT TO THE
CENTRAL FLORIDA COAST. MUCH OF THE REMAINDER OF THE SFC PATTERN
IS DOMINATED BY A WEAK 1019 MB HIGH NEAR 27N52W. A FEW LOW LEVEL
CYCLONIC SWIRLS/'SCREAMING EAGLES' ARE NOTED ROTATING AROUND
THIS RIDGING NEAR 22N54W AND 22N70W BUT NOTHING TO WARRANT
ADDING TO OUR SYNOPTIC SCALE MAP. THE SFC HIGH WILL SLIDE S
THROUGH FRI IN ADVANCE OF THE FRONTAL SYSTEM JUST N OF THE AREA.
THE TRADES ARE MOSTLY LIGHT ACROSS THE CENTRAL AND ERN ATLC DUE
TO THE WEAKNESS OF THE SFC RIDGE AND HOW FAR S IT IS LOCATED.
FAIR/STABLE WEATHER IS WIDESPREAD N OF 13N E OF 65W...ALTHOUGH
SCATTERED SHOWERS AND TSTMS WITH THE APPROACHING FRONT ARE
NEARING N OF 29N BETWEEN 57W-68W. BENIGN UPPER LOWS NOTED NEAR
21N55W AND 32N34W...WITH TYPICAL UPPER RIDGING OVER THE
REMAINDER OF THE E ATLC.

$$
WILLIS




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