[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 01 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM LAURA IS CENTERED NEAR 46.5N 46.5W AT 01/1500 UTC
OR ABOUT 270 NM EAST OF CAPE RACE NEWFOUNDLAND MOVING NNE AT 16
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 995 MB. MAXIMUM
SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE
THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. LAURA IS EXPECTED TO
LOSE ITS TROPICAL CHARACTERISTICS THIS AFTERNOON BUT MAINTAIN
ITS STRENGTH AND BECOME EXTRATROPICAL LATER THIS AFTERNOON. NO
DEEP CONVECTION REMAINS ASSOCIATED WITH LAURA. ADDITIONAL
INFORMATION ON THIS SYSTEM CAN BE FOUND IN THE HIGH SEAS
FORECASTS ISSUED BY THE NWS/OCEAN PREDICTION CENTER UNDER AWIPS/
WMO HEADERS NFDHSFAT1/FZNT01.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 38W S OF 19N MOVING W 10-15 KT. THIS
WAVE REMAINS EMBEDDED WITHIN DEEP LAYERED MOISTURE AS INDICATED
ON THE MIMIC-TPW ANIMATION WITH SCATTERED MODERATE CONVECTION
FROM 14N-17N BETWEEN 35W-41W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 6N-11N BETWEEN 36W-42W.

TROPICAL WAVE IS ALONG 49W FROM 12N-21N MOVING W NEAR 10 KT AND
IS BECOMING MORE TILTED IN A NE/SW ORIENTATION DUE TO AN UPPER
TROUGH/LOW AXIS ALONG 50W. CYCLONIC CURVATURE IN LOW-LEVEL
CLOUDS IS OBSERVED ON SATELLITE IMAGERY N OF 14N. NO ASSOCIATED
SHOWERS OR DEEP CONVECTION WITH THE WAVE.

TROPICAL WAVE IS ALONG 65W S OF 16N MOVING W 10-15 KT. WEAK WAVE
SIGNATURE IS NOTED ACROSS THE SW CARIBBEAN SEA WITH NO DEEP
CONVECTION OBSERVED.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 10N13W 7N20W 11N35W 9N41W 7N60W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 6N-9N BETWEEN 10W-16W AND FROM 5N-11N BETWEEN 19W-26W.
SIMILAR CONVECTION IS FROM 4N-9N BETWEEN 49W-55W.

...DISCUSSION...

GULF OF MEXICO...
DEEP UPPER TROUGH OVER THE ERN US EXTENDS OVER THE GULF WITH
MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR COVERING MUCH OF
THE REGION WITH THE EXCEPTION OF THE FLORIDA STRAITS. A SURFACE
TROUGH EXTENDS FROM THE W ATLC ACROSS EXTREME SRN FLORIDA AND
THE FLORIDA KEYS ALONG 25N80W TO OVER FAR WRN CUBA AND THE NRN
YUCATAN PENINSULA. A RE-ENFORCING COLD FRONT EXTENDS ACROSS THE
NRN GULF THROUGH THE BIG BEND AREA OF FLORIDA TO 28N90W AND
INLAND OVER TEXAS NEAR CORPUS CHRISTI. STRONG AND MOIST SW
MID-UPPER FLOW IS E OF THE SURFACE TROUGH PROVIDING SUPPORT FOR
SCATTERED SHOWERS/ISOLATED TSTMS OVER THE FLORIDA STRAITS.
SCATTERED LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE NOTED
ACROSS THE SW GULF S OF 22N WHILE THE REMAINDER OF THE REGION IS
RELATIVELY CLOUD FREE THIS AFTERNOON.

CARIBBEAN SEA...
AN UPPER RIDGE IS ANCHORED IN THE WRN CARIBBEAN NEAR 16N84W WITH
A RIDGE AXIS EXTENDING NE TO CENTRAL CUBA PRODUCING UPPER LEVEL
DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED TSTMS NW OF A
LINE FROM THE WINDWARD PASSAGE TO THE NICARAGUA/COSTA RICA
BORDER. A SECOND UPPER RIDGE EXTENDS INTO THE N/CENTRAL AND NE
CARIBBEAN N OF 15N E OF 75W ANCHORED BY AN UPPER HIGH OVER THE W
ATLC. SOMEWHAT STABLE CONDITIONS AND DRYER AIR ARE BENEATH THIS
RIDGE WITH ONLY A FEW ISOLATED SHOWERS FROM 14N-18N BETWEEN
63W-73W. A THIRD UPPER RIDGE IS OVER THE SE CARIBBEAN ANCHORED
OVER SOUTH AMERICA AND EXTENDING A RIDGE AXIS FROM NE VENEZUELA
ACROSS THE LESSER ANTILLES TO NEAR GRENADA. THE ITCZ AXIS
EXTENDS ALONG 9N IN THE SW CARIBBEAN SEA AND ACROSS CENTRAL
PANAMA INTO THE ERN PACIFIC GENERATING SCATTERED SHOWERS WITHIN
120 NM ALONG THE COAST OF NRN COLOMBIA AND PANAMA BETWEEN
67W-82W.

ATLANTIC OCEAN...
TROPICAL STORM LAURA IS LOCATED WELL N OF THE REGION...SEE
SPECIAL FEATURES ABOVE. THE DEEP UPPER TROUGH OVER THE ERN US
AND GULF OF MEXICO EXTENDS INTO THE W ATLC W OF 75W WITH THE
ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N69W SW TO
GRAND BAHAMA ISLAND WHERE A SURFACE TROUGH CONTINUES INTO A 1010
MB LOW NEAR 26N80W ALONG THE COAST OF FLORIDA NEAR PALM BEACH.
THE SW UPPER FLOW IS DRAWING ABUNDANT MOISTURE ACROSS THE AREA
PROVIDING THE UPPER SUPPORT FOR SCATTERED SHOWERS/ISOLATED TSTMS
WITHIN 150 NM E OF THE FRONT. A BROAD UPPER HIGH COVERS THE
REMAINDER OF THE W ATLC INTO THE CENTRAL ATLC AND S OVER THE NE
CARIBBEAN SEA CENTERED NEAR 25N64W. STRONG SUBSIDENCE AND DRY
STABLE AIR COVER THE AREA S OF 30N BETWEEN 59W-69W RESULTING IN
FAIR WEATHER OVER THAT AREA. A CUT-OFF UPPER LOW IS IN THE WRN
TROPICAL ATLC NEAR 18N51W TO THE W OF THE TROPICAL WAVE ALONG
49W. NEARLY ZONAL FLOW COVERS THE REMAINDER OF THE ATLC N OF 20N
E OF 44W. MULTILAYERED CLOUDINESS IS ACROSS THE CENTRAL ATLC
WITH POSSIBLE ISOLATED SHOWERS N OF 25N BETWEEN 36W-45W. THE
TYPICAL E/W UPPER RIDGE THAT DOMINATES THE TROPICAL ATLC EXTENDS
ALONG 15N TO 45W ANCHORED BY AN UPPER HIGH CENTERED NEAR 15N30W.
A SURFACE RIDGE EXTENDS FROM THE E ATLC THROUGH 32N29W SSE TO
THE CAPE VERDE ISLANDS AND A SECOND SURFACE RIDGE EXTENDS SW TO
NEAR 23N67W. VISIBLE SATELLITE IMAGERY SHOWS AFRICAN DUST
COVERING THE ERN ATLC FROM 10N-20N E OF 30W.

$$
HUFFMAN


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