[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 062354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON OCT 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
TROPICAL STORM MARCO IS CENTERED NEAR 19.7N 95.1W AT 07/0000 UTC
OR ABOUT 70 NM EAST-NORTHEAST OF VERACRUZ MEXICO MOVING WNW AT 6
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM
SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. SEE THE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/
WTNT23 KNHC FOR MORE DETAILS. MARCO IS A RELATIVELY SMALL
TROPICAL CYCLONE AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD
UP TO ABOUT 30 NM FROM THE CENTER. SCATTERED MODERATE CONVECTION
IS WITHIN 40 NM OF THE CENTER IN THE WRN BAY OF CAMPECHE.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 36W S OF 15N MOVING W NEAR 10-15 KT. A
SMALL MID-LEVEL CIRCULATION IS OBSERVED ON SATELLITE IMAGERY
CENTERED ALONG THE WAVE NEAR 10N. CLUSTERS OF SCATTERED SHOWERS
ARE FROM 10N-14N BETWEEN 35W-39W.

TROPICAL WAVE IS ALONG 62W S OF 18N MOVING W 10-15 KT. WEAK
CYCLONIC CIRCULATION IS NOTED IN THE LOW-MIDDLE LEVEL CLOUD
FIELD OVER THE ERN CARIBBEAN SEA. THE WAVE IS MOVING BENEATH
STRONG NW WINDS ALOFT...AND THEREFORE NO SHOWERS OR DEEP
CONVECTION ARE ASSOCIATED WITH THE WAVE.

TROPICAL WAVE IS ALONG 72W S OF 19N MOVING W NEAR 10 KT. WAVE IS
MOVING BENEATH AN AREA OF UPPER DIFFLUENCE AND HIGH CLOUDS ARE
OBSCURING ANY SIGNATURE AT LOWER LEVELS THEREFORE POSITION IS
BASED ON EXTRAPOLATION. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE ACROSS THE CENTRAL CARIBBEAN SEA BETWEEN 67W-78W
AND LIKELY THE RESULT OF THE UPPER-LEVEL DIFFLUENT PATTERN.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 10N14W 6N20W 10N33W 9N38W 7N50W
9N60W. SCATTERED MODERATE/STRONG CONVECTION IS INLAND ACROSS W
AFRICA AND EXTENDS INTO THE ADJACENT COASTAL WATERS FROM 5N-10N
BETWEEN 10W-14W. SIMILAR AREA OF CONVECTION IS FROM 3N-8N
BETWEEN 20W-26W. SCATTERED MODERATE CONVECTION IS FROM 7N-11N
BETWEEN 47W-55W.

...DISCUSSION...

GULF OF MEXICO...
TROPICAL STORM MARCO IS LOCATED IN THE BAY OF CAMPECHE...SEE
SPECIAL FEATURES ABOVE FOR MORE DETAILS. A BROAD UPPER RIDGE IS
ANCHORED ALONG THE NWRN COAST OF THE YUCATAN PENINSULA COVERING
ALL OF THE GULF WATERS BRINGING MOIST TROPICAL AIR ACROSS MOST
OF THE GULF S OF A LINE FROM NE FLORIDA NEAR 30N81W TO S OF
BROWNSVILLE TEXAS. A WEAK SURFACE TROUGH EXTENDS FROM THE W ATLC
ACROSS CENTRAL FLORIDA INTO THE NE GULF NORTH OF ST. PETERSBURG
WEST TO NEAR 28N90W. SCATTERED SHOWERS AND TSTMS ARE ACROSS MUCH
OF THE FLORIDA PENINSULA...INCLUDING ADJACENT COASTAL GULF
WATERS AND A PORTION OF THE NE GULF FROM 28N-30N BETWEEN
85W-89W. SCATTERED SHOWERS ARE ALSO ACROSS THE SW GULF FROM
21N-24N BETWEEN 92W-96W DUE TO THE UPPER DIFFLUENT PATTERN
ALOFT. MODERATE SUBSIDENCE/DRY AIR ALOFT IS ACROSS THE NW GULF
WITH THE NEXT FRONTAL BOUNDARY EXPECTED TO ENTER THE GULF LATE
TUE AFTERNOON.

CARIBBEAN SEA...
A BROAD UPPER RIDGE COVERS THE NW CARIBBEAN W OF THE CAYMAN
ISLANDS ANCHORED ALONG THE NWRN COAST OF THE YUCATAN PENINSULA.
TO THE EAST IS AN UPPER LOW CENTERED SW OF JAMAICA NEAR 14N82W
EXTENDING UPPER TROUGHING SW TO COSTA RICA AND WRN PANAMA. THE
CENTRAL AND SERN CARIBBEAN IS DOMINATED BY A BROAD UPPER RIDGE
ANCHORED OVER NW VENEZUELA. BETWEEN THE UPPER LOW AND UPPER
RIDGE...AN UPPER DIFFLUENT PATTERN RESIDES ACROSS THE CENTRAL
CARIBBEAN BRINGING SCATTERED SHOWERS AND ISOLATED TSTMS FROM
INLAND ACROSS NRN VENEZUELA TO 17N BETWEEN 66W-78W. MODERATE TO
STRONG SUBSIDENCE/DRY AIR IS NOTED ACROSS THE ERN GREATER
ANTILLES AND THE FAR NRN LEEWARD ISLANDS. A FEW ISOLATED SHOWERS
ARE ACROSS PUERTO RICO THIS EVENING...BUT FAIR WEATHER
CONDITIONS REMAIN ELSEWHERE N OF 17N AND E OF 72W.

ATLANTIC OCEAN...
A LINGERING SURFACE TROUGH REMAINS ACROSS THE W ATLC EXTENDING
FROM A STATIONARY FRONT N OF THE REGION ALONG 32N70W TO NEAR
MELBOURNE FLORIDA AND ACROSS THE CENTRAL FLORIDA PENINSULA. AN
UPPER RIDGE EXTENDING FROM THE THE SE GULF DOMINATES THE W ATLC
W OF 65W GENERATING SCATTERED SHOWERS AND TSTMS ACROSS THE
FLORIDA PENINSULA AND SCATTERED SHOWERS FROM 26N-30N W OF 76W. A
LARGE CUT-OFF UPPER LOW IS IN THE CENTRAL ATLC CENTERED NEAR
21N61W WITH A SURFACE TROUGH EXTENDING FROM 28N57W TO 21N60W
PRODUCING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM OF THE
SURFACE TROUGH. AN UPPER TROUGH CONTINUES TO DIG SW OVER THE NE
ATLC INTO THE ERN TROPICAL ATLC THROUGH 32N12W SW TO 15N40W WITH
AN UPPER RIDGE CENTERED NEAR 14N20W TO OVER THE CANARY ISLANDS...
THUS PRODUCING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS W
OF THE CAPE VERDE ISLANDS FROM 15N-19N BETWEEN 25W-30W.

$$
HUFFMAN




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