[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261150
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT AUG 26 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...
TROPICAL STORM ERNESTO IS CENTERED NEAR 15.0N 70.6W AT 26/1200
UTC MOVING WNW AT 14 KT OR ABOUT 245 NM SOUTH SOUTH-WEST OF
SANTO DOMINGO IN THE DOMINICAN REPUBLIC AND 455 NM EAST
SOUTH-EAST OF KINGSTON JAMAICA. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 997 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 40 KT
WITH GUSTS TO 50 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER
HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. LOW LEVEL CENTER
IS NOW EMBEDDED WITHIN THE STRONGEST CONVECTION.
SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN A 60 NM RADIUS OF
14.5N69.5W WITH SCATTERED MODERATE/ ISOLATED STRONG CONVECTION
COVERING THE REMAINDER OF THE AREA FROM 12N-17N BETWEEN 65W-71W.
OUTER RAINBANDS ARE TO THE N AND E OF THE SYSTEM AND COVERS THE
AREA FROM 13N-20N BETWEEN 60W-80W INCLUDING THE LEEWARD/VIRGIN
ISLANDS...PUERTO RICO...HISPANIOLA AND JAMAICA WITH RAINFALL
AMOUNTS OF 2 TO 4 INCHES EXPECTED AND HIGHER AMOUNTS ARE
POSSIBLE IN MOUNTAINOUS REGIONS.

TROPICAL STORM DEBBY WAS DOWNGRADED TO TROPICAL DEPRESSION AT
26/0900 UTC. DEBBY IS CENTERED NEAR 25.3N 46.7W AT 26/0900 UTC
MOVING WNW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009
MB. THE MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40
KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER HEADERS
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. THE LOW LEVEL CENTER IS
NOW COMPLETELY EXPOSED WITH SCATTERED MODERATE CONVECTION FROM
27N-30N BETWEEN 45W-47W.

...TROPICAL WAVES...
A 1009 MB LOW IS MOVING OVER THE EASTERN MOST CAPE VERDE ISLANDS
NEAR 16N22W MOVING W 10-15 KT. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE N OF THE LOW WITHIN WITHIN 60 NM OF LINE
19N20W-20N25W.

TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 85W S OF 20N MOVING W
15-20 KT. WAVE IS BENEATH A STRONG UPPER LOW PARTIALLY MASKING
THE SATELLITE SIGNATURE. WAVE IS MOVED MOSTLY INLAND OVER
CENTRAL AMERICA WHILE THE N PORTION IS EMBEDDED WITHIN DRY
AIR...LIMITING ANY CONVECTION IN THE CARIBBEAN.

...THE ITCZ...
ITCZ IS CENTERED ALONG 12N15W 6N32W 7N52W 9N62W ACROSS THE N
PORTION OF SOUTH AMERICA...PANAMA...AND COSTA RICA NEAR 9N83W
INTO THE E PACIFIC REGION. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE WITHIN 150 NM OF THE AXIS FROM 16W-26W AND WITHIN
90/120 NM OF THE ITCZ FROM 43W-50W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS S OF 12N W OF 75W TO INLAND OVER
PANAMA...COSTA RICA...AND NICARAGUA.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE DOMINATES THE GULF ANCHORED OVER THE CENTRAL
MISSISSIPPI VALLEY WITH A WEAK UPPER TROUGH EMBEDDED OVER THE
CENTRAL GULF FROM THE YUCATAN PENINSULA TO THE N GULF COAST NEAR
THE MISSISSIPPI DELTA...REMNANTS OF THE UPPER LOW. AN UPPER
RIDGE EXTENDS ACROSS N/CENTRAL FLORIDA INTO THE W ATLC. THIS IS
PRODUCING SCATTERED SHOWERS/THUNDERSTORMS OVER THE NE GULF N OF
27N E OF 85W TO INLAND OVER N FLORIDA WITH ISOLATED SHOWERS
ACROSS THE REMAINDER OF THE N GULF N OF 27N. THE SURFACE RIDGE
FROM THE W ATLC HAS WEAKENED AS IT EXTENDS OVER THE FLORIDA
PENINSULA TO THE CENTRAL GULF.

CARIBBEAN SEA...
FOCUS OF WEATHER TONIGHT IN THE CARIBBEAN IS TROPICAL STORM
ERNESTO AND THE CONVECTION ASSOCIATED WITH THE ITCZ AXIS ACROSS
THE SE CARIBBEAN. A LARGE UPPER LOW REMAINS OVER THE N/CENTRAL
CARIBBEAN JUST W OF JAMAICA COVERING THE AREA N OF 14N W OF 74W.
THIS UPPER LOW WILL PRODUCE WEAK SHEAR OVER THE NEXT FEW DAYS AS
ERNESTO CONTINUES TO MOVE ACROSS THE CARIBBEAN. BROAD UPPER HIGH
IS LOCATED JUST TO THE E OF ERNESTO PRODUCING GOOD OUTFLOW
MAINLY OVER THE ISLANDS NE OF THE ERNESTO.

ATLANTIC OCEAN...
DEEP LEVEL TROUGH IS OVER THE NW ATLC JUST N OF THE REGION WITH
THE ASSOCIATED FRONTAL BOUNDARY EXTENDING THROUGH BERMUDA THEN
AS A SURFACE TROUGH ALONG 30N TO THE E COAST OF THE US. JUST TO
THE S IS THE UPPER RIDGE THAT EXTENDS FROM GULF OF MEXICO ACROSS
N/CENTRAL FLORIDA TO BEYOND 32N58W. THIS IS GENERATING SCATTERED
SHOWERS/THUNDERSTORMS FROM 25N-30N BETWEEN 76W-79W AND N OF 30N
FROM 71W-77W. A SMALL...ELONGATED UPPER LOW IS NOTED NEAR 24N70W
WITH THE TROUGH EXTENDING INTO THE LARGE UPPER LOW IN THE N
CARIBBEAN. A LARGE UPPER LOW IS IN THE CENTRAL ATLC NEAR 28N53W
WITH A TROUGH EXTENDING S TO NEAR 21N54W. THIS IS GENERATING
ONLY WIDELY ISOLATED SHOWERS AS IT IS EMBEDDED WITHIN VERY DRY
AIR. THE INTERACTION OF THE E PORTION OF THIS UPPER LOW AND THE
W PORTION OF LARGE SCALE MID/UPPER RIDGING OFF THE COAST OF
AFRICA IS GENERATING THE STRONG SOUTHERLY SHEAR OVER DEBBY. A
1028 MB HIGH IS JUST NE OF THE AZORES WITH RIDGE AXIS EXTENDING
SW TO N OF DEBBY INTO THE W ATLC AND THE E GULF OF MEXICO. MORE
AFRICA DUST IS BEING DRAWN INTO THE FAR E ATLC BUT MAINLY FROM
20N-28N E OF 30W.

$$
WALLACE




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