[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI SEP 02 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION FOURTEEN IS CENTERED NEAR 20.6N 48.1W...OR
860 NM ENE OF THE NORTHERN LEEWARD ISLANDS...AT 02/0900 UTC
MOVING NW AT 9 KT. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH
GUSTS TO 40 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT34 KNHC FOR MORE DETAILS. THE LOW LEVEL CENTER
REMAINS PARTIALLY EXPOSED AS CONVECTION IS NOW CLOSER TO THE LOW
LEVEL CENTER. AN UPPER LOW TO ITS SW IS PRODUCING SOMEWHAT OF A
SSW SHEAR AND DRAWING THE DEEPEST CONVECTION NW OF THE LOW LEVEL
CENTER. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 75 NM OF
LINE 21N48W-23.5N52W. WITH THE SHEAR IN PLACE...FURTHER
DEVELOPMENT IS NOT EXPECTED FOR AT LEAST THE NEXT DAY OR TWO.
HOWEVER THE SHEAR IS EXPECTED TO LESSEN AFTER THAT TIME AND
FURTHER STRENGTHENING COULD OCCUR.

A 1008 MB LOW IS EMBEDDED WITHIN THE ITCZ NEAR 7N35W MOVING W
RATHER RAPIDLY NEAR 20 KT. ALTHOUGH THIS SYSTEM HAS NOT YET
SHOWN SIGNS OF FURTHER ORGANIZATION...THE UPPER LEVEL
ENVIRONMENT IS BECOMING MORE FAVORABLE. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS NE OF THE LOW WITHIN 60 NM OF LINE
9N36.5W-12.5N34W. SCATTERED MODERATE CONVECTION IS W OF THE LOW
LEVEL CENTER FROM 6N-10N BETWEEN 38W-42W. CONDITIONS ARE TO
REMAIN FAVORABLE FOR FURTHER STRENGTHENING AND HAS THE POTENTIAL
OF BECOMING A TROPICAL DEPRESSION OVER THE NEXT DAY OR TWO.

...TROPICAL WAVES...

TROPICAL WAVE OFF THE COAST AFRICA IS ALONG 21W MOVING W NEAR 10
KT. BROAD CYCLONIC TURNING IS OBSERVED ON THE FIRST VISIBLE
SATELLITE IMAGES. SCATTERED MODERATE/STRONG CONVECTION IS FROM
13N-17N BETWEEN THE COAST OF AFRICA AND 20W.

TROPICAL WAVE IN THE SE CARIBBEAN IS ALONG 62W/63W S OF 13N
MOVING W 5-10 KT. WAVE APPEARS DEFINED INLAND OVER SOUTH AMERICA
WITH LITTLE EVIDENCE IN THE CARIBBEAN SEA AND ANY
SHOWERS/THUNDERSTORMS ARE INLAND AS WELL.

TROPICAL WAVE MOVING FROM CENTRAL AMERICA TO OVER THE YUCATAN IS
ALONG 88W S OF 18N MOVING W NEAR 20 KT. WELL DEFINED CYCLONIC
TURNING IS OBSERVED IN THE E PACIFIC REGION WITH LITTLE EVIDENCE
IN THE CARIBBEAN. SCATTERED MODERATE CONVECTION IS IN THE GULF
OF HONDURAS S OF 18N W OF 87W TO INLAND OVER CENTRAL AMERICA
INTO THE E PACIFIC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N16W 12N29W 7N35W...THEN ALONG
6N39W 12N51W 13N61W. CLUSTERS OF SCATTERED MODERATE CONVECTION
ARE FROM 4N-10N BETWEEN 20W-28W. THE REMAINDER OF THE CONVECTION
IS ASSOCIATED WITH THE TROPICAL WAVE AND LOW.

...DISCUSSION...

GULF OF MEXICO...
A LARGE...ELONGATED UPPER LEVEL HIGH IS CENTERED ALONG THE NORTH
AND SOUTH CAROLINA COASTLINE AND AN ASSOCIATED RIDGE AXIS
EXTENDS SW ACROSS THE W FLORIDA PANHANDLE TO THE TEXAS COAST
NEAR CORPUS CHRISTI. THIS FEATURE IS PRODUCING A LARGE SWATH OF
E/SE FLOW OVER MAJORITY OF THE GULF OF MEXICO...WHICH ALSO
HAPPENS TO BE PUMPING LARGE AMOUNTS OF TROPICAL MOISTURE OVER
THE AREA FROM THE W ATLC. AN INVERTED UPPER TROUGH LOCATED ON
THE SW SIDE OF THE RIDGE...EXTENDING FROM THE W BAY OF CAMPECHE
TO EXTREME NE MEXICO. THE UPPER TROUGH IS PRODUCING AN AREA OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ON ITS DIFFLUENT W
SIDE INLAND OVER MEXICO WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS OVER THE SW GULF S OF 23N W OF 94W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS REMAIN IN THE STRAITS OF FLORIDA
S OF 25N W OF 85W. ALTHOUGH GENERAL HIGH PRESSURE IS CENTERED
OVER THE AREA WITH A STRONGER RIDGE INCHING INTO THE N GULF OVER
LOUISIANA AT THE SURFACE...A WEAK SURFACE TROUGH EXTENDS FROM A
1012 MB LOW E OF FLORIDA/GEORGIA BORDER NEAR 31N79W SW ALONG
27N83W TO 25N88W AND THIS COULD BE A FOCUS FOR THUNDERSTORMS IN
THE COMING DAYS. DEEP TROPICAL MOISTURE COVERS VIRTUALLY THE
ENTIRE AREA AT THE MOMENT...WHICH EXPLAINS THE HIGH COVERAGE OF
THUNDERSTORM ACTIVITY...BUT A MID/UPPER LEVEL TROUGH IS EXPECTED
TO MOVE IN LATE IN THE WEEKEND AND WILL PUSH THIS AIR MASS OVER
THE S GULF BY MON.

CARIBBEAN...
AN ELONGATED CLOSED UPPER LOW IS CENTERED S OF CUBA OVER THE
CAYMAN ISLANDS WITH THE TROUGH EXTENDING FROM CENTRAL CUBA NEAR
20N80W TO THE COAST OF THE YUCATAN PENINSULA NEAR N BELIZE. A
FAIRLY SOLID JET IS RACING FROM NICARAGUA/HONDURAS SE ALONG
17N80W THEN NE ACROSS HISPANIOLA INTO THE SW ATLC AND IS PUMPING
MOISTURE OVER THE NW CARIBBEAN WITH CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION OVER THE NW CARIBBEAN N OF
18N TO INLAND OVER CUBA FROM 78W-87W. ELSEWHERE...A RIDGE AXIS
EXTENDS FROM A HIGH OVER THE LEEWARD/VIRGIN ISLANDS NEAR 18N63W
SW TO N OF PANAMA NEAR 11N82W. THIS IS KEEPING THE STRONGEST
SUBSIDENCE OVER THE E/CENTRAL CARIBBEAN AND HENCE NO CONVECTION
E OF 78W. A LARGE AREA OF DRY AIR IS EXPECTED TO REMAIN OVER THE
CARIBBEAN THROUGH AT LEAST MON WITH THE GREATEST MOISTURE
LIMITED TO THE FAR SW CARIBBEAN AND NEAR THE YUCATAN CHANNEL.

WEST ATLANTIC...
A STATIONARY FRONT IS HUNG-UP ALONG THE N PORTION OF THE W ATLC
HOOKING UP WITH A 1012 MB LOW E OF FLORIDA/GEORGIA BORDER NEAR
31N79W SW ACROSS FLORIDA NEAR DAYTONA BEACH. THE TEMP/DEWPOINT
CONTRASTS REMAIN IN CONTRARY TO A FRONTAL BOUNDARY BUT THERE IS
SOME SORT OF WIND SHIFT BOUNDARY. THIS SURFACE LOW/TROUGH IS
BENEATH THE UPPER RIDGE AXIS THAT HAS BEEN CONTROLLING THE GULF
FOR THE PAST FEW DAYS. IN ADDITION...A 1011 MB LOW REMAINS S OF
BERMUDA NEAR 30N65W WITH A SURFACE TROUGH EXTENDING SW TO
25N72W. THIS FEATURE LIES JUST W OF AN UPPER LOW THAT HAS BEEN
IN PLACE FOR A FEW DAYS NEAR 31N58W...WITH AN EXTENSIVE TROUGH
WHICH EXTENDS SW TO A SECOND UPPER LOW N OF THE PUERTO RICO NEAR
23N67W TO CENTRAL CUBA...WHICH THEN CONNECTS TO THE UPPER LOW
OVER THE NW CARIBBEAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE NEAR THE SURFACE TROUGH FROM 24N-30N BETWEEN 60W-76W. THE
UPPER RIDGE IS EXPECTED TO TURN MORE E/W OVER THE NEXT FEW DAYS
THUS PUSHING THE UPPER TROUGH TO THE E. THE UPPER TROUGH IS
FORECASTED TO BECOME A COMPLEX SERIES OF UPPER LOWS WHICH COULD
BRING MORE UNSETTLED WEATHER TO THE AREA. THIS MODEL RUN IS VERY
DIFFERENT THAN THE PAST FEW NIGHTS...SO THIS SCENARIO REMAINS TO
BE SEEN.

EAST/CENTRAL ATLANTIC...
TROPICAL DEPRESSIONS FOURTEEN IS CENTERED OVER THE CENTRAL ATLC
AND IS INTERMINGLED WITH STRONG SHEAR-INDUCING UPPER LOW NEAR
18N55W. FARTHER E OVER THE E ATLC...BROAD NW FLOW EXTENDS OVER
THE SUBTROPICS E OF 43W AND IS DIGGING AN UPPER TROUGH DOWN TO
THE CANARY ISLANDS THEN LIFTING NE OVER MOROCCO AND
SPAIN/PORTUGAL. A SHORTWAVE IS DROPPING DOWN THE BACK SIDE OF
THE TROUGH AND IS EXPECTED TO DEVELOP A CUT-OFF LOW JUST SSW OF
THE AZORES IN THE NEXT 24 TO 36 HRS. A WEAK UPPER HIGH IS
LOCATED S OF THE TROUGH NEAR 13N36W WITH FAIRLY CONSISTENT
EASTERLY FLOW S OF 15N.

$$
WALLACE



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