[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 030006
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 2 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2330 UTC.

...SPECIAL FEATURES...

RAPIDLY STRENGTHENING CATEGORY 5 HURRICANE FELIX WAS CENTERED
NEAR 13.8N 72.9W OR ABOUT 340 NM SE OF KINGSTON JAMAICA AT
03/0000 UTC...MOVING WEST-NORTHWEST AT 16 KT. THE LATEST MINIMUM
CENTRAL PRESSURE ESTIMATED FROM RECONNAISSANCE DATA IS 934 MB.
MAXIMUM SUSTAINED WINDS HAVE INCREASED TO 145 KT WITH GUSTS TO
175 KT. FELIX CONTINUES ON A WNW PATH STEERED BY A STRONG
DEEP-LAYER RIDGE OVER THE WESTERN ATLANTIC. FELIX CONTINUES TO
LOOK VERY IMPRESSIVE ON SATELLITE IMAGERY WITH A WELL DEFINED
EYE EMBEDDED IN A SYMMETRICAL CENTRAL DENSE OVERCAST. NUMEROUS
MODERATE TO STRONG CONVECTION IS WITHIN 80 NM OF THE CENTER.
SCATTERED MODERATE EXISTS ELSEWHERE WITHIN 260 NM N...NEARING
THE S SHORE OF HISPANIOLA...AND WITHIN 180 NM S OVER NRN
VENEZUELA AND COLOMBIA. SEE LATEST NHC INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE
FULL FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS INCLUDING THE LATEST WATCH AND WARNING
INFORMATION.

A 1009 MB LOW PRES SYSTEM IS CENTERED NEAR 12N39W MOVING W NEAR
10 KT. SHOWER AND TSTM ACTIVITY ASSOCIATED WITH THIS SYSTEM
REMAIN LIMITED AND DISORGANIZED...AND DISPLACED TO THE W/NW OF
THE CENTER WITH PERSISTENT UPPER E/SE SHEAR OVER THE SYSTEM S OF
A STRONG UPPER HIGH. SCATTERED MODERATE IS FROM 11N-13N BETWEEN
40W-44W. ALTHOUGH UPPER-LEVEL WINDS ARE NOT PARTICULARLY
FAVORABLE FOR DEVELOPMENT...THE CIRCULATION REMAINS WELL-DEFINED
AND THERE IS STILL SOME POTENTIAL FOR THIS SYSTEM TO BECOME A
TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS. THE TROPICAL
WAVE AXIS THIS LOW HAS BEEN ALONG THE PAST FEW DAYS WILL BE
DROPPED FROM THE 03/0000 UTC MAP SINCE THERE IS LITTLE CYCLONIC
TURNING NOTED OUTSIDE OF ITS IMMEDIATE VICINITY. HOWEVER...THE
BROAD LOW TO MID LEVEL TURNING FURTHER W BETWEEN 50W-58W HAS A
MORE CLASSIC INVERTED V SHAPE AND SEEMS ASSOCIATED WITH THE SAME
SYSTEM OVERALL. THUS...A TROPICAL WAVE IN THE VICINITY OF 54W
WILL REMAIN ON THE NEXT ANALYSIS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 21W S OF 21N ESTIMATED TO BE MOVING W
NEAR 15 KT. SOUNDING DATA FROM DAKAR SHOWS THE WAVE PASSAGE
SOMETIME BEFORE 00Z LAST NIGHT. IN ADDITION...THIS MORNINGS
SOUNDING FROM SAL SUGGESTS THAT THE MID TO UPPER LEVEL PORTION
OF THE WAVE HAS PASSED...WITH THE SFC/NEAR SFC PORTION OF THE
WAVE JUST TO THE E OF SAL AS ALSO NOTED IN A RECENT QUIKSCAT
PASS FROM 02/1930 UTC. SATELLITE IMAGERY CONTINUES TO SHOW A
BROAD REGION OF LOW AND MID LEVEL TURNING ASSOCIATED WITH THIS
WAVE. REGARDLESS...SHOWER ACTIVITY IS CURRENTLY VERY LIMITED AND
LIKELY BEING SUPPRESSED BY STABLE LOW TO MID LEVEL AIR
SURROUNDING THIS FEATURE.

TROPICAL WAVE WAS ADDED ALONG 53W S OF 20N ESTIMATED TO BE
MOVING W NEAR 15 KT. AS NOTED IN SPECIAL FEATURES SECTION...THIS
WAVE APPEARS TO BE ASSOCIATED WITH THE SAME SYSTEM NEAR
12N39W...BUT THE TWO FEATURES NOW APPEAR TO BE DETACHED. THE
WAVE HAS A CLASSIC APPEARANCE IN THE SURROUNDING BUOY/SHIP
OBSERVATIONS AND SATELLITE IMAGERY...THOUGH SHOWER AND TSTM
ACTIVITY IS MINIMAL.

TROPICAL WAVE IS IN THE W CARIB ALONG 83W/84W S OF 21N MOVING W
NEAR 15 KT. THE WAVE CONTINUES TO INTERACT WITH A MID TO UPPER
TROUGH TO ITS W TO PRODUCE SCATTERED SHOWERS AND ISOLATED TSTMS
WITHIN 150 NM EITHER SIDE OF THE WAVE AXIS.

THE NRN EXTENSION OF A TROPICAL WAVE IS OVER S MEXICO ALONG 93W
S OF 18N. REFER TO THE EAST PACIFIC DISCUSSION...MIATWDEP...FOR
DETAILS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N22W 11N30W 13N37W 9N41W 9N52W.
SCATTERED MODERATE CONVECTION IS WITHIN 210 NM S OF THE AXIS
BETWEEN 23W-32W. ISOLATED MODERATE IS FROM 7N-9N BETWEEN
43W-53W.

DISCUSSION...

GULF OF MEXICO...
A DECAYING FRONT IS STALLED ACROSS THE N GULF COAST EXTENDING
FROM N FLORIDA TO THE TEXAS COAST GENERALLY ALONG 29N...BUT
SEEMS TO HAVE PUSHED A LITTLE FURTHER NORTH OVER THE LAST FEW
HOURS. A WIND SHIFT IS STILL EVIDENT AROUND THE BOUNDARY THOUGH
THE THERMAL GRADIENT CONTINUES TO WANE. THE FRONT IS PRODUCING
ISOLATED SHOWERS AND TSTMS NEAR THE GULF COAST AND OVER THE S.E.
U.S. MORE CONCENTRATED SCATTERED SHOWERS AND TSTMS ARE IN THE
WRN-MOST GULF S OF 28N W OF 94W ASSOCIATED WITH A LOW-LEVEL
TROUGH ALONG 97W AND A HIGHLY DIFFLUENT UPPER PATTERN. THE
REMAINDER OF THE AREA IS RELATIVELY TRANQUIL WITH PATCHES OF
ISOLATED SHOWERS ROTATING AROUND AN INVERTED MID TO UPPER TROUGH
WHICH EXTENDS NWD FROM THE YUCATAN INTO THE CENTRAL GULF. SFC
OBS INDICATE THAT WINDS ARE LIGHT AND VARIABLE IN THE E AND MUCH
OF THE CENTRAL GULF BUT INCREASE OUT OF THE E/SE IN THE W GULF
WHERE THE GRADIENT TIGHTENS. WINDS/SEAS EXPECTED TO REMAIN ON
THE LOW SIDE OVER THE NEXT DAY OR SO WITH WEAK HIGH PRES
DEVELOPING OVER THE MIDDLE GULF.

CARIBBEAN SEA...
EXTREMELY DANGEROUS HURRICANE FELIX IS THE MAIN EVENT IN THE
CARIB BASIN. ALL INTERESTS IN THE CENTRAL AND WESTERN CARIBBEAN
SEA SHOULD CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM. IN
GENERAL...FELIX IS EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF
2 TO 4 INCHES OVER THE GUAJIRA PENINSULA OF NORTHERN COLOMBIA.
FOR MORE DETAILS ON FELIX REFER TO THE SPECIAL FEATURE SECTION
ABOVE. THE INTERACTION BETWEEN A TROPICAL WAVE IN THE W CARIB
ALONG 83W AND AN INVERTED MID TO UPPER TROUGH IS PRODUCING A
FAIR AMOUNT OF SHOWER ACTIVITY IN THE FAR W CARIB AND NOW MOVING
INLAND OVER CENTRAL AMERICA AND THE YUCATAN PENINSULA. SEE ABOVE
FOR MORE DETAILS. ELSEWHERE...MID TO UPPER RIDGING N OF FELIX IS
EXPECTED TO EXPAND W STEERING FELIX TO THE WNW OVER THE NEXT
COUPLE OF DAYS ACROSS THE CARIB SEA.

ATLANTIC OCEAN...
A SLOW MOVING FRONTAL ZONE STRETCHES E-W ALONG OUR N BORDER FROM
S OF BERMUDA NEAR 30N65W TO NEAR THE FLORIDA/GEORGIA BORDER.
DOPPLER RADAR SHOWS SOME CYCLONIC ROTATION OF THE ASSOCIATED
SCATTERED SHOWER ACTIVITY OFF THE GEORGIA COAST FROM 29N-32N
BETWEEN 79W-81W. SOME SLOW DEVELOPMENT IS POSSIBLE IN THIS AREA
OVER THE NEXT COUPLE OF DAYS. BUOY DATA IN THIS AREA ALSO
SUGGEST A WEAK LOW MAY BE FORMING. SCATTERED SHOWERS ARE ALSO N
OF 26N BETWEEN 56W-65W. THIS IS PRIMARILY ASSOCIATED WITH
INSTABILITY AHEAD OF THE AFOREMENTIONED FRONT. HIGH LEVEL
CLOUDINESS ORIGINATING FROM THIS ACTIVITY SPREADS MUCH FARTHER S
DRIVEN BY STRONG NLY FLOW BETWEEN AN UPPER HIGH CENTERED NEAR
26N68W AND AN UPPER LOW NEAR 25N54W. ANOTHER MID TO UPPER LEVEL
LOW IS NOTED JUST E OF SE FLORIDA NEAR 24N79W. THIS ALONG WITH
LEFTOVER DIURNAL FORCING IS SUPPORTING ISOLATED SHOWERS/TSTMS
OVER THE BAHAMAS...SE FL...AND CUBA. IN THE E ATLC...A
DOMINATING UPPER HIGH REMAINS PARKED ACROSS THE AREA CENTERED
NEAR 23N29W. ABUNDANT DRY AIR ALOFT IS EMBEDDED WITHIN THIS
RIDGE. STRONG E TO SELY FLOW NEAR THE SW PERIPHERY OF THIS HIGH
IS SHEARING THE SPECIAL FEATURE NEAR 12N39W. ELSEWHERE AT THE
SFC...A 1020 MB HIGH IS NEAR 25N66W...WHILE MODERATE RIDGING
DOMINATES THE E ATLC S OF A 1028 MB HIGH NEAR 46N20W. THIS
PATTERN HAS ALLOWED TRADES TO REMAIN LIGHT TO MODERATE ACROSS
MOST OF THE AREA.

$$
WILLIS


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