[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN OCT 21 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

THE TROPICAL WAVE THAT WAS PREVIOUSLY ANALYZED ALONG 52W/53W ON
THE 06Z SURFACE MAP WAS RELOCATED ALONG 50W/51W BASED ON LATEST
VIS SATELLITE IMAGERY THAT SHOWS A VERY WELL DEFINED INVERTED-V
PATTERN ASSOCIATED WITH THIS FEATURE. THIS WAVE CONTINUES TO
SHOW UP WELL IN LOW LEVEL SATELLITE DERIVED WINDS...AND THE
UW-CIMSS TPW PRODUCT WITH A GOOD SURGE OF MOISTURE. SCATTERED
MODERATE CONVECTION IS MAINLY EAST OF AXIS FROM 7N-16N BETWEEN
45W-51W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 6N30W 11N49W 11N53W 10N63W.
BESIDES FOR THE ACTIVITY ASSOCIATED WITH THE TROPICAL SCATTERED
MODERATE CONVECTION IS WITHIN 180 NM N OF AXIS WEST OF 26W.
SIMILAR CONVECTION IS SEEN OVER THE WINDWARD ISLANDS AND NE
VENEZUELA.

DISCUSSION...

GULF OF MEXICO...
THE STATIONARY FRONT THAT WAS OVER THE CENTRAL GULF IS BEGINNING
TO MOVE NWD AS A WARM FRONT. AS OF 1500 UTC...THE WARM FRONT
EXTENDS ACROSS N-CENTRAL FLORIDA TO THE CENTRAL GULF NEAR 26N90W
TO 25N96W. THIS FRONT AND ASSOCIATED MOISTURE/SHOWERS WILL
CONTINUE TO LIFT N OVER THE NORTHERN GULF WATERS TONIGHT. A
CLUSTER OF MODERATE CONVECTION IS ALONG THE FRONTAL BOUNDARY
COVERING FROM 24N-27N BETWEEN 84W-87W. THIS CONVECTIVE ACTIVITY
IS JUST AHEAD OF A SHORTWAVE TROUGH LOCATED OVER THE EASTERN
GULF WHILE AN UPPER HIGH SITUATED NEAR 22N92W DOMINATES THE
WESTERN HALF OF THE REGION. THE COMBINATION OF THE FRONT AND THE
UPPER TROUGH IS ALSO SUPPORTING SCATTERED SHOWERS AND ISOLATED
TSTMS OVER NORTH FLORIDA. A SFC RIDGE ANCHORED ON A HIGH OVER
NORTH CAROLINA IS IN CONTROL OF THE SE U.S. AND THE NORTHERN
GULF WATERS. THIS HIGH IS EXPECTED TO MOVE E FAIRLY QUICKLY OVER
THE NEXT COUPLE OF DAYS IN ADVANCE OF THE NEXT STRONGER COLD
FRONT EXPECTED TO MOVE OFF THE TEXAS COAST MONDAY MORNING. GALE
CONDITIONS ARE STILL EXPECTED ACROSS THE WESTERN GULF...BEHIND
THE COLD FRONT MONDAY NIGHT THROUGH TUE.

CARIBBEAN SEA...
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER THE NW CARIBBEAN
MAINLY WEST OF 85W ASSOCIATED WITH A SFC TROUGH AND A WEAK 1008
MB LOW LOCATED NEAR 18N87W AT 21/1500 UTC. THESE SYSTEMS ARE
FORECAST TO MOVE INLAND OVER THE YUCATAN PENINSULA/BELIZE LATE
THIS AFTERNOON. THE TROUGH IS ANALYZED FROM 24N86W TO 14N89W
CROSSING HONDURAS. UPPER DIFFLUENCE AROUND THE SE PERIPHERY OF
AN UPPER HIGH OVER THE WESTERN GULF IS ENHANCING THIS CONVECTIVE
ACTIVITY. AN UPPER-LEVEL LOW REMAINS OVER THE E CARIBBEAN AND
NOW IS LOCATED JUST SOUTH OF DOMINICAN REPUBLIC. THIS UPPER
SYSTEM HAS A TROUGH EXTENDING SW TOWARDS PANAMA AND NE THROUGH
PUERTO RICO INTO THE CENTRAL ATLC. SWLY WINDS AHEAD OF THE
TROUGH HAVE BEEN ADVECTING ABUNDANT TROPICAL MOISTURE FROM
NORTHERN SOUTH AMERICA THROUGH THE EASTERN CARIBBEAN INTO THE
TROPICAL NORTH ATLANTIC. SCATTERED SHOWERS AND ISOLATED TSTMS
ARE OVER THIS AREA. TRADES ARE MODERATE OVER THE CENTRAL AND ERN
CARIBBEAN...AND BEND MORE SE IN THE WRN PORTION EAST OF THE
TROUGH NEAR THE GULF OF HONDURAS.

ATLANTIC OCEAN...
A STATIONARY FRONT IS OVER THE WRN ATLC...ENTERING THE AREA NEAR
31N68W AND CONTINUING MAINLY WEST OVER N-CENTRAL FLORIDA.
SCATTERED SHOWERS AND TSTMS ARE ALONG THE FRONTAL BOUNDARY. THE
UPPER PATTERN OVER THE WRN ATLC IS STILL DOMINATED BY A LARGE
ANTICYCLONE CENTERED NEAR 28N73W. NELY WINDS BETWEEN THIS HIGH
AND AN ELONGATED UPPER TROUGH THAT EXTENDS SW ACROSS MUCH OF THE
CENTRAL ATLC ARE TRANSPORTING VERY DRY AIR ACROSS THE CENTRAL
AND SE BAHAMAS...EASTERN CUBA...HISPANIOLA AND JAMAICA. THE
ELONGATED UPPER-LEVEL TROUGH IS SUPPORTING A SFC TROUGH ALONG
31N32W 25N40W 25N56W...WHICH EXTENDS SW FROM A 1015 MB LOW
LOCATED NEAR THE AZORES. SCATTERED SHOWERS ARE GENERALLY WITHIN
120 NM EITHER SIDE OF THE SFC TROUGH. THE REMAINDER OF THE ATLC
FORECAST AREA IS UNDER THE INFLUENCE OF A RIDGE AROUND A 1027 MB
HIGH N OF THE AREA NEAR 38N42W AND ANOTHER WEAK 1024 MB HIGH
CENTERED JUST E OF PORTUGAL. A WEAK UPPER-LEVEL LOW HAS
DEVELOPED WITHIN 225 NM N OF THE CAPE VERDE ISLANDS AND IS
GENERATING ISOLATED SHOWERS.

$$
GR




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