[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 02 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730 UTC.

...TROPICAL WAVES...
A NEW ERN ATLC TROPICAL WAVE IS ADDED TO THE 1200 UTC MAP ALONG
20W/21W S OF 17N MOVING W 15 TO 20 KT. CYCLONIC CURVATURE IS
SEEN IN LOW CLOUD MOTIONS ON VISIBLE IMAGERY...BUT THE MAIN
JUSTIFICATION FOR ADDING THIS WAVE LIES IN THE VEERING SEEN IN
THE LOW LEVEL WINDS IN THE DAKAR SOUNDING OVER THE LAST 24 TO
36HRS. CLOUD TOPS HAVE WARMED A FEW DEGREES OVER THE ASSOCIATED
CLUSTER OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION THAT
MOVED OFF AFRICA LAST EVENING...THOUGH SCATTERED MODERATE STILL
LIES FROM 11N-16N BETWEEN 22W-25W. GFS SEEMS TO HAVE THIS
INITIALIZED FAIRLY WELL...THOUGH THE MODELS PLACEMENT IS
SLIGHTLY E OF MINE. THERE MAY BE A WEAK SURFACE LOW FORMING
ALONG THIS WAVE BUT MY CONFIDENCE IN THIS AT 1200 UTC WAS NOT
HIGH.

TROPICAL WAVE IS ALONG 39W S OF 18N WITH A 1009 MB LOW ALONG THE
WAVE NEAR 11N MOVING W NEAR 10 KT. BROAD ELONGATED LOW/MID LEVEL
CIRCULATION IS OBSERVED ON SATELLITE IMAGERY. SCATTERED MODERATE
CONVECTION IS OBSERVED FROM 12N-15N BETWEEN 36W-44W. ISOLATED
SHOWERS/TSTMS ARE NOTED S OF 11N WITHIN 150 NM OF EITHER SIDE OF
THE AXIS. THE CLUSTER OF MODERATE CONVECTION E OF THE WAVE MAY
BE MORE ASSOCIATED WITH THE ITCZ. THIS SYSTEM HAS SOME POTENTIAL
FOR DEVELOPMENT OVER THE NEXT FEW DAYS.

TROPICAL WAVE MOVING THROUGH THE LESSER ANTILLES IS ALONG 60W S
OF 19N WITH A 1010 MB LOW ALONG THE WAVE NEAR 15N MOVING W 10 TO
15 KT. THE SHOWER ACTIVITY HAS BECOME A LITTLE BETTER ORGANIZED
DURING THE PAST FEW HOURS AND SURFACE PRESSURES HAVE BEEN
FALLING. HOWEVER...UPPER-LEVEL WINDS ARE EXPECTED TO BECOME ONLY
SLIGHTLY MORE CONDUCIVE FOR DEVELOPMENT...IF ANY AT ALL.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM
12N-19N BETWEEN 58W-65W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N17W 12N22W 12N37W 11N43W 12N57W
AND REEMERGES IN THE SW CARIBBEAN NEAR THE COLOMBIAN COAST NEAR
10N76W AND EXTENDS W THROUGH PANAMA AND EXITS INTO THE EPAC NEAR
PAVONES COSTA RICA. ASIDE FROM THE ACTIVITY ASSOCIATED WITH THE
TROPICAL WAVES/LOWS...A COUPLE CLUSTERS OF SCATTERED MODERATE
WITH ISOLATED STRONG CONVECTION ARE BEGINNING TO MOVE OFF THE
COAST OF AFRICA FROM 13N-20N BETWEEN AFRICA AND 19W. SCATTERED
MODERATE CONVECTION IS FROM 8N-15N BETWEEN 32W-37W. CLUSTERS OF
MODERATE CONVECTION ARE ALSO AFFECTING THE SW CARIBBEAN SEA OFF
CENTRAL AMERICA.

...DISCUSSION...

GULF OF MEXICO...
THE MOST ACTIVE WEATHER IN THE GULF THIS AFTERNOON LIES IN THE
FLORIDA STRAITS AND FAR SE GULF. DOPPLER RADAR SHOWS NUMEROUS
SHOWERS AND TSTMS IN THIS REGION...LIKELY ASSOCIATED WITH UPPER
DIFFLUENT AIR BETWEEN A WEAK MID TO UPPER LEVEL SHORT WAVE RIDGE
EXTENDING THROUGH THE ERN GULF...AND THE UPPER LOW SEEN SPINNING
OVER THE SE BAHAMAS. A NARROW UPPER TROUGH IS EXTENDING NE
THROUGH THE BAY OF CAMPECHE...THROUGH THE CENTRAL GULF AND
TOWARDS THE WRN FLORIDA PANHANDLE. THERE IS A WEAK REFLECTION OF
THIS AS A TROUGH AT THE SURFACE...EXTENDING FROM 21N96W TO
30N84W. ISOLATED SHOWERS AND TSTMS ARE WITHIN 100NM OF THIS
AXIS. THE FAR NW GULF IS QUIET WITH VERY DRY MID TO UPPER LEVEL
AIR DOMINATING ON THE E SIDE OF AN UPPER HIGH OVER NRN MEXICO.
OVERALL A FAIRLY WEAK GRADIENT WITH LIGHT WINDS/LOW SEAS
EXPECTED TO DOMINATE THE GULF SFC PATTERN OVER THE NEXT COUPLE
DAYS.

CARIBBEAN SEA...
FAIR WEATHER DOMINATES MUCH OF THE CARIBBEAN OUTSIDE OF THE
TROPICAL WAVE AND SURFACE LOW OVER THE WINDWARD ISLANDS AND THE
ITCZ ACTIVITY OFF CENTRAL AMERICA. THERE ARE A FEW ISOLATED
SHOWERS AND TSTMS MOVING S INTO THE NW CARIBBEAN WATERS S OF
CUBA...AROUND THE W SIDE OF THE UPPER LOW OVER THE SE BAHAMAS. A
MID TO UPPER LEVEL HIGH IS SEEN JUST NORTH OF THE WAVE/LOW OVER
THE WINDWARD ISLANDS. MID TO UPPER LEVEL SW FLOW ON THE W OF
THIS HIGH/SE OF THE LOW OVER THE SE BAHAMAS IS STREAMING HIGH
CLOUDS TO THE NE BETWEEN COLOMBIA/VENEZUELA AND PUERTO
RICO/VIRGIN ISLANDS. 10-20 KT TRADES DOMINATE MUCH OF THE
CARIBBEAN. THIS WILL PERSIST OVER THE NEXT 24HRS WHILE
SHOWERS/TSTMS CONTINUE MOVING THROUGH THE ERN CARIBBEAN.

ATLANTIC OCEAN...
AN UPPER HIGH IS SEEN ON WV IMAGERY JUST ESE OF CAPE HATTERAS.
UPPER DIFFLUENT AIR BETWEEN THIS FEATURE AND THE UPPER LOW OVER
THE SE BAHAMAS IS HELPING TO SUPPORT THE SCATTERED SHOWERS AND
TSTMS IN THE FAR WRN ATLC AND ACROSS THE BAHAMAS/S FLORIDA FROM
22N-29N BETWEEN 75W-81W. ISOLATED SHOWERS/TSTMS ARE ROTATING
CYCLONICALLY AROUND THE UPPER LOW OVER THE SE BAHAMAS FROM
22N-69W BETWEEN 65W-75W. A BENIGN UPPER LOW IS SEEN SPINNING
NEAR 26N45W. MID TO UPPER LEVEL HIGHS ARE SEEN NEAR 18N31W AND
ANOTHER OVER THE COAST OF AFRICA NEAR 19N15W. AT THE SURFACE...A
1021MB HIGH S OF THE AZORES IS CENTERED NEAR 33N30W. THE
ANTICYCLONIC FLOW AROUND THIS HIGH IS DOMINATING MUCH OF OUR
ATLANTIC AREA N OF 15N. EXTENSIVE DRY AIR ALONG WITH A DENSE
SAHARAN DUST EXTENDS OUT TO NEAR 50W MAINLY N OF 15N.


$$
WILLIS


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