[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191106
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN 19 SEP 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLC 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 STORM JEANNE IS CENTERED NEAR 23.2N 72.5W...OR WITHIN
65 MILES NNE OF MAYAGUANA ISLAND IN THE SOUTHEASTERN BAHAMAS AT
19/0900 UTC MOVING NNW AT 6 KT. MAXIMUM SUSTAINED WIND SPEED IS
40 KT WITH GUSTS TO 50 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
1001 MB. SEE LATEST NHC PUBLIC ADVISORY OR NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC OR MIATCMAT1/
WTNT21 KNHC FOR MORE DETAILS. THE CONVECTION REMAINS POORLY
ORGANIZED AND IS LIMITED TO NE OF THE LOW LEVEL CIRCULATION. A
MID/UPPER LOW IS CENTERED SE OF JEANNE ALONG THE COAST OF CUBA
NEAR 21N75W. THIS IS LIMITING OUTFLOW TO THE WEST. SCATTERED
STRONG CONVECTION IS WITHIN A 45 NM RADIUS OF 22.5N70.5W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 75/90 NM
OF LINE FROM 22N69W-25N73W.

HURRICANE KARL IS CENTERED NEAR 16.3N 42.2W...OR ABOUT 1050 NM W
OF THE CAPE VERDE ISLANDS OR ABOUT 1100 NM E OF THE LESSER
ANTILLES AT 19/0900 UTC MOVING WNW AT 10 KT. MAXIMUM SUSTAINED
WIND SPEED IS 100 KT WITH GUSTS TO 120 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 960 MB. SEE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. A
SMALL EYE HAS REDEVELOPED BUT IS STILL OVERCAST. HURRICANE KARL
HAS SEVERAL SPIRAL BANDS IN ALMOST EVERY QUADRANT AND GOOD
OUTFLOW IN ALL DIRECTIONS. IN PARTICULAR...A OUTFLOW JET APPEARS
TO EXTEND TO THE NE OF KARL DUE TO AN UPPER LOW LOCATED ABOUT
740 NM NE OF KARL. SCATTERED MODERATE/STRONG CONVECTION COVERS
THE AREA FROM 13N-21N BETWEEN 37W-46W.

A STRONG TROPICAL WAVE IS LOCATED JUST W OF THE CAPE VERDE
ISLANDS ALONG 30W/31W S OF 19N MOVING W 10-15 KT WITH A 1010 MB
LOW ALONG THE WAVE NEAR 13N. A MID LEVEL LOW IS OBSERVED ON
INFRARED SATELLITE IMAGERY. SCATTERED MODERATE/STRONG CONVECTION
IS FROM 13N-15N BETWEEN 30W-33W. THIS SYSTEM HAS THE POTENTIAL
OF TROPICAL CYCLONE DEVELOPMENT OVER THE NEXT FEW DAYS AS IT
MOVES WESTWARD.

...TROPICAL WAVES...

TROPICAL WAVE JUST W OF BARBADOS IS ALONG 60W S OF 22N MOVING W
10-15 KT. VERY LITTLE INDICATION OF THE WAVE IS PRESENT ON
INFRARED SATELLITE IMAGERY. THIS WAVE IS BENEATH UPPER LEVEL
RIDGING E OF T.S. JEANNE. THE PRESENCE OF STRONG SUBSIDENCE AT
THE UPPER LEVELS AND DRY AIR AT THE SURFACE IS LIMITING SHOWERS
OVER THE WINDWARD ISLANDS. SCATTERED THUNDERSTORMS ARE FROM
16N-20N BETWEEN 60W AND THE LEEWARD ISLANDS.

...ITCZ...

ITCZ AXIS EXTENDS ALONG 18N10W 9N15W 17N40W 11N45W 6N58W. THE
ITCZ CONTINUES TO BE DISTORTED BY THE TROPICAL WAVES AND
HURRICANE KARL. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN 75 NM OF LINE FROM 6N23W-11N26W. CLUSTERS OF SIMILAR
CONVECTION ARE WITHIN 45/60 NM OF LINE FROM 7N13W-9N21W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 1N-6N BETWEEN
14W-27W.

...DISCUSSION...

GULF OF MEXICO...
STRONG COLD FRONT CONTINUES TO GRADUALLY PUSH S OVER THE FLORIDA
PENINSULA S OF LAKE OKEECHOBEE THEN DISSIPATING ACROSS THE GULF.
THE FRONT WAS PROBABLY HELPED ALONG BY THE CIRCULATION/TROF
ASSOCIATED WITH EX-HURRICANE IVAN. IT HAS BROUGHT IN VERY DRY
AIR BEHIND THE FRONT. A DEEP LAYERED TROF SITUATED ALONG THE
EASTERN SEABOARD AND TRAILING INTO THE E GULF HAS BROUGHT STRONG
SUBSIDENCE OVER THE AREA AT THE MID/UPPER LEVELS. FARTHER W...AN
UPPER LEVEL HIGH IS CENTERED OVER CNTRL MEXICO AND IT APPEARS
THAT THE ASSOCIATED UPPER LEVEL DIVERGENCE IS STILL TRIGGERING
ISOLATED SHOWERS/THUNDERSTORMS ALONG S OF TEXAS TO THE BAY OF
CAMPECHE.

CARIBBEAN...
THE NORMAL EASTERLY TRADES ARE PRETTY MUCH NON-EXISTENT ACROSS
THE CARIBBEAN ENTERING THE THIRD STRAIGHT DAY DUE TO THE
WEAKENED GRADIENT CAUSED BY T.S. JEANNE. THIS HAS PRODUCED
HIGHER THAN NORMAL TEMPERATURES OVER THE LESSER ANTILLES ALONG
THE COAST OF SOUTH AMERICA. A MID/UPPER LEVEL HIGH IS OVER THE
LEEWARD ISLANDS NEAR 18N64W WITH RIDGE AXIS EXTENDING TO THE NW
TO 26N72W AND THE EXPANDING ANTICYCLONIC OUTFLOW OF T.S. JEANNE.
SURFACE TROF EXTENDS FROM S OF JEANNE ACROSS HAITI ALONG 16N75W
TO 13N80W IN THE SW CARIBBEAN. SCATTERED MODERATE/STRONG
CONVECTION IS N OF 16N TO INLAND OVER THE DOMINICAN REPUBLIC AND
SIMILAR CONVECTION IS OVER LAKE MARACAIBO. SCATTERED
THUNDERSTORMS ARE FROM 17N-20N INCLUDING HAITI AND JAMAICA.

SUBTROPICAL ATLANTIC...
STRONG RIDGING CONTINUES OVER THE W ATLC WITH AN UPPER LEVEL
HIGH LOCATED NEAR 33N66W. MID/UPPER LEVEL TROF EXTENDS INTO THE
CNTRL ATLC FROM A MID/UPPER LEVEL LOW CENTERED NEAR 32N56W SW TO
25N62W. MOISTURE FROM T.S. JEANNE IS FEEDING INTO THIS TROF ON
THE E SIDE PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 90/120 NM OF LINE FROM 23N58W-32N52W. AN UPPER RIDGE LIES
TO THE E OF THIS LOW ALONG 20N60W TO BEYOND 32N44W AND TWO
MID/UPPER LOWS CONTINUE TO SWIRL OVER THE E ATLC NEAR 25N33W AND
30N16W. THE EASTERNMOST LOW IS BRINGING DRIER AIR OVER THE
CANARY ISLANDS BUT A FEW SHOWERS MAY BE EMBEDDED WITHIN THE
MID/UPPER LEVEL CLOUDINESS OVER W SAHARA AND MOROCCO.

TROPICAL ATLANTIC...
AN UPPER LEVEL RIDGE AND UPPER LEVEL MOISTURE IS SITUATED OVER
THE LEEWARD ISLANDS EXTENDING NEWD INTO THE SUBTROPICAL WATERS
BUT DRIER AIR IS MOVING IN FROM THE E BETWEEN 47W-60W ALONG AN
INVERTED TROF FROM 13N55W-22N49W. A SECOND UPPER RIDGE EXTENDS
TO THE E OF HURRICANE KARL ALONG 15N WITH STRONG WLY FLOW
PROBABLY AN OUTFLOW JET JUST TO THE N BETWEEN 20N-25N.

$$
WALLACE



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