[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 22 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.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 24W S OF 14N MOVING W NEAR 5-10 KT.
THIS WAVE CONTINUES TO REMAIN WEAK AND EMBEDDED WITHIN THE ITCZ.
NO ORGANIZED SHOWERS OR DEEP CONVECTION ASSOCIATED WITH THE WAVE.

A TROPICAL WAVE IS ALONG 52W/53W S OF 21N MOVING W NEAR 10 KT.
THE SSMI-TPW PRODUCT FROM CIMSS INDICATES A NORTHWARD SURGE OF
MOISTURE ALONG THE WAVE AXIS. THE WAVE IS INTERACTING WITH AN
UPPER-LEVEL LOW NEAR 22N55W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 11N-21N BETWEEN 44W-49W.

A TROPICAL WAVE IS ALONG 79W S OF 17N MOVING W NEAR 10-15 KT.
THE WAVE IS EMBEDDED WITHIN STRONG EASTERLY SURFACE FLOW ACROSS
THE CARIBBEAN AND IS ENHANCING CONVECTION ACROSS THE WRN
CARIBBEAN FROM 11N-16N BETWEEN 77W-82W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N13W 9N22W 7N26W 11N51W 11N55W
11N65W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM
5N-10N BETWEEN 29W-48W. SIMILAR CONVECTION IS FROM 10N-13N
BETWEEN 59W-62W ACROSS THE SRN WINDWARD ISLANDS.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER-LEVEL HIGH CENTERED OVER JAMAICA EXTENDS WEAK
RIDGING ACROSS THE ENTIRE GULF AND FLORIDA PENINSULA PRODUCING
SW UPPER-LEVEL FLOW. MODERATE TO STRONG SUBSIDENCE/DRY AIR IS
NOTED OVER MUCH OF THE SW AND NE GULF. AT THE SURFACE...A
SURFACE TROUGH EXTENDS FROM A 1012 MB LOW NEAR 23N95W ALONG 95W
TO NEAR 28N. CYCLONIC TURNING IS OBSERVED ALONG THE TROUGH AXIS
WITH ISOLATED SHOWERS FROM 25N29N BETWEEN 92W-95W. ELSEWHERE...
A 1011 MB LOW IS LOCATED OFF THE NRN BELIZE COAST NEAR 18N88W
AND EXTENDS A SURFACE TROUGH ACROSS THE YUCATAN PENINSULA AND SE
GULF TO NEAR 25N83W. SCATTERED/NUMEROUS SHOWERS COVER THE SE
GULF AND FLORIDA STRAITS FROM 20N-26N E OF 88W...INCLUDING THE
SRN FLORIDA PENINSULA. A SURFACE HIGH PRESSURE RIDGE EXTENDS
FROM THE W ATLC ACROSS NRN FLORIDA AND THE NRN GULF WATERS N OF
27N. A COLD FRONT IS FORECAST TO ENTER THE NW GULF WATERS BY
EARLY THURSDAY BRINGING MODERATE TO STRONG NORTHERLY WINDS IN
WAKE OF THE FRONT.

CARIBBEAN SEA...
A 1011 MB SURFACE LOW PRESSURE IS CENTERED OFF THE NRN BELIZE
COAST NEAR 18N88W WITH A SURFACE TROUGH EXTENDING NWD ACROSS THE
ERN YUCATAN PENINSULA. SCATTERED SHOWERS COVER MUCH OF THE NW
CARIBBEAN WITH MOST INTENSE ACTIVITY FROM 17N-20N BETWEEN
83W-88W. THIS LOW IS EXPECTED TO MOVE N-NW AHEAD OF THE COLD
FRONT FORECAST TO ENTER THE NW GULF OF MEXICO EARLY THURSDAY. AN
UPPER-LEVEL HIGH CENTERED OVER JAMAICA DOMINATES THE ENTIRE
CARIBBEAN SEA IS HELPING TO INDUCE THE CONVECTIVE ACTIVITY OVER
THE NW CARIBBEAN AND ALSO THE TROPICAL WAVE ALONG 79W. MODERATE
TRADE WINDS OF 15 TO 20 KT ARE BLOWING ACROSS THE BASIN. AN AREA
OF SCATTERED SHOWERS AND ISOLATED TSTMS ARE MOVING ACROSS THE
SRN WINDWARD ISLANDS AND FAR SE CARIBBEAN. THIS ACTIVITY APPEARS
TO BE THE RESULT OF THE UPPER DIFFLUENT PATTERN IN PLACE.

ATLANTIC OCEAN...
ZONAL UPPER-LEVEL FLOW IS ACROSS THE W ATLC W OF 60W. WEAK
UPPER-LEVEL RIDGING EXTENDS FROM THE CARIBBEAN N TO ACROSS THE
BAHAMAS. MULTILAYERED CLOUDINESS AND ISOLATED SHOWERS ARE ACROSS
THE NRN BAHAMAS AS LOW-MIDDLE LEVEL MOISTURE STREAMS NE FROM THE
SURFACE TROUGH ACROSS THE SE GULF OF MEXICO. A DEEP LAYERED
TROUGH IS OVER THE CENTRAL ATLC WITH AN UPPER LOW CENTERED NEAR
22N55W. THE ATTENDANT COLD FRONT ENTERS THE AREA NEAR 32N51W
EXTENDING TO NEAR 23N59W. SCATTERED SHOWERS RELATED TO THIS
FRONT ARE FROM 25N-31N BETWEEN 48W-54W. A SURFACE TROUGH EXTENDS
NWD FROM THE TROPICAL WAVE ALONG 52W/53W FROM 22N52W TO 28N51W.
POSSIBLE SCATTERED SHOWERS ARE EAST OF THIS TROUGH FROM 21N-27N
BETWEEN 42W-49W. ELSEWHERE...MODERATE TO STRONG SUBSIDENCE IS IN
PLACE ACROSS THE W ATLC N OF 27N AND W OF THE COLD FRONT. AREAS
OF LOW-LEVEL CLOUDS AND MODERATE TRADE WINDS ARE OBSERVED OVER
THE E ATLC LARGELY IN PART TO A SURFACE RIDGE COVERING THE E
ATLC E OF 40W. AN UPPER-LEVEL TROUGH WITH AXIS JUST WEST OF THE
THE CANARY AND CAPE VERDE ISLANDS IS SUPPORTING A COLD FRONT
ENTERING THE DISCUSSION AREA NEAR 32N9W OVER MOROCCO EXTENDING
WWD TO NEAR 31N23W. POSSIBLE ISOLATED SHALLOW SHOWERS ARE WITHIN
120 NM OF THE FRONT.

$$
HUFFMAN




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