[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON OCT 27 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.

...TROPICAL WAVES...
A TROPICAL WAVE IS ABOUT MIDWAY BETWEEN THE CAPE VERDE ISLANDS
AND THE LESSER ANTILLES ALONG 43W S OF 16N MOVING W 10-15 KT. A
LARGE AREA OF SHOWERS AND TSTMS IS ASSOCIATED WITH THIS WAVE.
ALTHOUGH THIS SYSTEM IS SHOWING SOME SIGNS OF ORGANIZATION...ANY
FURTHER DEVELOPMENT SHOULD BE SLOW TO OCCUR AS THE SYSTEM
CONTINUES TO MOVE SLOWLY WESTWARD OVER THE NEXT COUPLE OF DAYS.
SCATTERED MODERATE CONVECTION IS WITHIN 200 NM E OF WAVE AXIS
FROM 8N-14N. STRONG UPPER DIFFLUENCE IS ENHANCING CONVECTION IN
THIS AREA.

A TROPICAL WAVE IS ALONG 56W/57W S OF 15N MOVING W 10-15 KT. A
DIFFLUENT PATTERN ALOFT BETWEEN AN UPPER-LEVEL HIGH OVER THE
CARIBBEAN SEA AND AN UPPER-LEVEL TROUGH OVER THE N TROPICAL ATLC
IS HELPING TO INDUCE SOME SHOWER ACTIVITY NEAR THE NORTHERN END
OF THE WAVE AXIS.

...THE ITCZ...
ITCZ AXIS IS ANALYZED ALONG 10N15W 8N30W 9N41W 7N50W 7N61W.
SCATTERED MODERATE CONVECTION IS FROM 3N-11N BETWEEN 22W-34W...
AND FROM 9N-14N BETWEEN 35W-40W.

...DISCUSSION...

GULF OF MEXICO...
AN UNUSUALLY STRONG 1040 MB SURFACE HIGH IS CENTERED OVER
NORTHERN TEXAS. AT THE LEADING EDGE OF THIS CONTINENTAL POLAR
AIRMASS IS A STRONG COLD FRONT THAT EXTENDS ACROSS NORTH FLORIDA
AND THE NORTHERN GULF WATERS. A ROPE CLOUD DELINEATES THE
FRONTAL BOUNDARY WHICH IS RAPIDLY MOVING ACROSS THE GULF REGION
AS SEEN ON VIS SATELLITE PICTURES. THE FRONT IS EXPECTED TO
CLEAR THE ENTIRE GULF BY EARLY TUE MORNING WITH TEMPERATURES
DROPPING TO NEAR THE RECORDS ACROSS SOUTH FLORIDA TUESDAY NIGHT/
WEDNESDAY MORNING. AN EARLIER ASCAT PASS SHOWED INCREASING NLY
WINDS OF 20 TO 30 KT BEHIND THE FRONT...AND NLY WINDS OF 15 TO
20 KT AHEAD OF THE FRONTAL SYSTEM. A DEEP LAYERED TROUGH OVER
THE E CONUS SUPPORTS THE AFOREMENTIONED COLD FRONT...WITH STRONG
MID/UPPER-LEVEL WESTERLY WINDS OVER THE N GULF. AS HIGH PRES
BUILDS IN...A VERY TIGHT PRES GRADIENT HAS DEVELOPED ALONG AND
INLAND THE MEXICAN COAST. AS A RESULT...STRONG NLY WINDS ARE
BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC PRODUCING A GAP WIND
EVENT IN THE E PACIFIC REGION. THESE WINDS ARE ALREADY REACHING
GALE FORCE...AND ARE EXPECTED TO INCREASE TO STORM FORCE BY 1800
UTC TUESDAY.

CARIBBEAN SEA...
A NEARLY STATIONARY FRONTAL BOUNDARY STRETCHES ACROSS THE GULF
OF HONDURAS AND WESTERN CUBA...THEN CONTINUES AS A COLD FRONT
OVER THE BAHAMAS AND THE W ATLC TO A 1010 MB LOW LOCATED NEAR
39N67W. A 120 NM WIDE BAND OF MULTILAYERED CLOUDS WITH SCATTERED
SHOWERS AND ISOLATED TSTMS IS RELATED TO THE FRONT ACROSS THE
CARIBBEAN SEA WITH THE STRONGEST SHOWER ACTIVITY OVER CENTRAL
CUBA. THE DEEP LAYERED TROUGH OVER THE EASTERN U.S. ALSO
SUPPORTS THIS FRONT. AN UPPER-LEVEL HIGH CENTERED BETWEEN
HISPANIOLA AND THE SE BAHAMAS EXTENDS A RIDGE OVER MOST OF THE
BASIN. SWLY FLOW N OF THIS UPPER RIDGE CONTINUES TO TRANSPORT
DEEP TROPICAL MOISTURE INTO THE NW CARIBBEAN WHICH IS
INTERACTING WITH THE ABOVE MENTIONED STATIONARY FRONT. AN
UPPER-LEVEL TROUGH FROM THE
CENTRAL ATLC CLIPS THE FAR SE CARIBBEAN AND THE WINDWARD
ISLANDS. A PATCH OF LOW LEVEL MOISTURE WITH EMBEDDED LIGHT
SHOWERS IS MOVING ACROSS THE NORTHERN LEEWARD ISLANDS INTO THE
VIRGIN ISLANDS AND EASTERN PUERTO RICO. THIS CLOUDINESS IS
LIKELY ASSOCIATED WITH THE REMNANTS OF A FRONTAL BOUNDARY...
ANALYZED AS A SFC TROUGH OVER THE CENTRAL ATLC ON THE 1800 UTC
MAP. LOW-TOPPED TRADE WIND SHOWERS ARE SEEN OVER THE E AND
CENTRAL CARIBBEAN. THE COLD FRONT CURRENTLY OVER THE GULF OF
MEXICO...WHICH IS MOVING RAPIDLY SE WILL MERGE WITH THE
STATIONARY FRONT OVER THE NW CARIBBEAN. THE MERGED FRONT WILL
CONTINUE TO MOVE SE AND STALL FROM E CUBA TO NE HONDURAS TUE
AFTERNOON.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH OVER THE E CONUS IS APPROACHING THE W
ATLC...WITH STRONG MID/UPPER LEVEL FLOW ROTATING AROUND THE BASE
OF THE TROUGH INTO THE W ATLC. THESE WINDS ARE ADVECTING
MID/UPPER LEVEL MOISTURE FROM THE NW CARIBBEAN AND THE SE GULF
OF MEXICO INTO THE W ATLC. A MUCH DRIER AND COOLER AIRMASS WILL
BEGIN TO PUSH ACROSS THE W ATLC TONIGHT...WHICH IS BEING USHERED
IN BY A COLD FRONT THAT IS CURRENTLY MOVING SOUTHWARD ACROSS
NORTHERN FLORIDA. FURTHER TO THE E...UPPER LEVEL ANTICYCLONIC
FLOW ASSOCIATED WITH THE UPPER-LEVEL HIGH LOCATED BETWEEN
HISPANIOLA AND THE SE BAHAMAS COVERS MUCH OF THE CENTRAL ATLC.
ANOTHER DEEP LAYERED TROUGH ENTERS THE FORECAST AREA NEAR 31N41W
THEN CONTINUES SW TO THE WINDWARD ISLANDS/FAR SE CARIBBEAN. THIS
TROUGH IS SUPPORTING THE SURFACE TROUGH THAT EXTENDS ACROSS THE
CENTRAL ATLC ALONG 31N42W 22N50W TO THE NORTHERN LEEWARD
ISLANDS. ISOLATED SHOWERS ARE ALONG THE TROUGH AXIS. THE E
ATLC...WHERE GENERALLY FAIR WEATHER CONDITIONS PREDOMINATE...IS
UNDER THE INFLUENCE OF A SFC RIDGE ANCHORED ON HIGH SITUATED
WELL N OF THE AREA. AN EAST-TO-WEST UPPER-LEVEL RIDGE DOMINATES
THE DEEP TROPICS...PARTICULARLY E OF 45W AND IS ENHANCING
CONVECTION ALONG THE ITCZ AXIS.

$$
GR


WWWW
This weather bulletin was brought to you by:
www.nashvilleweather.net