[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311131
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE OCT 31 2006

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 63W S OF 13N MOVING W
NEAR 10-15 KT.  THIS WAVE ALONG WITH THE ITCZ IS GENERATING
SCATTERED MODERATE CONVECTION OVER SOUTHERN VENEZUELA.
ELSEWHERE...NO SIGNIFICANT CONVECTION IS NOTED.

A TROPICAL WAVE IS ALONG 81/82W S OF 21N MOVING W NEAR 15 KT. A
1008 MB LOW IS ALONG THE WAVE AXIS NEAR 18N. CLUSTERS OF
MODERATE TO ISOLATED STRONG CONVECTION ARE BEHIND THE WAVE AXIS
FROM 12N-21N BETWEEN 76W-81W. THIS CONVECTIVE ACTIVITY IS
AFFECTING JAMAICA AND THE CAYMAN ISLANDS WITH HEAVY SHOWERS AT
TIMES. THE GFS MODEL SHOWS A VORTICITY MAXIMUM IN THIS AREA THAT
SHOULD MOVE NW DURING THE NEXT 24 HOURS. DEVELOPMENT OF THIS
SYSTEM...IF ANY...SHOULD BE SLOW TO OCCUR.

A TROPICAL WAVE IS ALONG 88W S OF 16N MOVING W 10 TO 15 KT.  A
1010 MB SURFACE LOW IS ON THE NORTHERN END OF THE WAVE AXIS OVER
THE GULF OF HONDURAS NEAR 17N86W. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE RELATED TO THIS LOW.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 9N30W 8N40W 4N51W. SCATTERED
MODERATE/ISOLATED CONVECTION IS FROM 5N-10N WEST OF 20W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 5N-13N BETWEEN 20W-26W.
SIMILAR CONVECTION IS FROM 4N-9N BETWEEN 42W-48W.

...DISCUSSION...
THE GULF OF MEXICO...
AN UPPER LEVEL RIDGE AND A VERY DRY/STABLE ATMOSPHERE COVERS THE
ENTIRE GULF. A SHORT WAVE TROUGH IS OVER MEXICO MOVING EWD.
SURFACE HIGH PRESSURE RIDGING DOMINATES THE GULF OF MEXICO WITH
RIDGE AXIS EXTENDING FROM THE FLORIDA PANHANDLE TO THE BAY OF
CAMPECHE. COLD AIR STRATOCUMULUS CLOUDS ARE STILL VISIBLE OVER
THE GULF WATERS...PARTICULARLY W OF 92W. THE SURFACE HIGH
PRESSURE WILL CONTINUE TO MOVE EASTWARD GIVING THE AREA ELY
LIGHT WINDS OVER THE EASTERN GULF AND STRONGER SLY FLOW OF 15-20
KT OVER THE WESTERN PORTION OF THE GULF. NEXT COLD FRONT WILL
MOVE OFF NW GULF COAST EARLY WED. STRONG HIGH PRESSURE WILL
FOLLOW THE FRONT.

THE CARIBBEAN SEA...
A BROAD AREA OF LOW PRESSURE DOMINATES THE NW CARIBBEAN WITH A
COUPLE OF TROPICAL WAVES/LOWS. SEE TROPICAL WAVES SECTION. IN
ADDITION...A LARGE CLUSTER OF MODERATE TO ISOLATED STRONG
CONVECTION IS OVER N COLOMBIA. PATCHES OF LOW LEVEL MOISTURE
WITH EMBEDDED SHOWERS ARE MOVING ACROSS THE EASTERN CARIBBEAN
UNDER AN ELY SURFACE FLOW. IN THE UPPER LEVELS...ABUNDANT UPPER
LEVEL MOISTURE EXISTS IN THE CENTRAL AND WESTERN WEST OF 72W. AN
UPPER HIGH REMAINS OVER HISPANIOLA WITH A RIDGE EXTENDING OVER
THE NW CARIBBEAN AND NORTHERN CENTRAL AMERICA. DIFFLUENCE
ASSOCIATED WITH THIS SYSTEM IS IS SUPPORTING THE DEVELOPMENT OF
SHOWER/TSTMS ACTIVITY RELATED TO THE TROPICAL WAVE/LOW LOCATED
ALONG 81/82W. AN INVERTED TROUGH LIES ALONG 78W SOUTH OF 16N.
PLENTY OF DRY/STABLE AIR ALOFT RESULTING IN MODERATE TO STRONG
SUBSIDENCE DOMINATES THE EASTERN CARIBBEAN EAST OF 72W...
INCLUDING PUERTO RICO...THE VIRGIN ISLANDS AND THE LESSER
ANTILLES. 15-20 TRADE WINDS ARE BLOWING ACROSS THE BASIN WITH
THE STRONGEST WINDS JUST NORTH OF THE COLOMBIA COAST.

THE ATLANTIC OCEAN...
A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE ATLC. STRONG SWLY
WINDS AHEAD OF AN UPPER TROUGH LOCATED OVER THE W ATLC AND
NORTHERN BAHAMAS ARE ADVECTING TROPICAL MOISTURE FROM THE W
CARIBBEAN ACROSS CUBA AND THE BAHAMAS INTO THE W ATLC BEYOND
31N60W. THE ATTENDANT FRONTAL BOUNDARY ENTERS THE AREA NEAR
32N50W THEN CONTINUES SW ALONG 25N60W 25N73W. THIS FRONTAL
BOUNDARY IS FORECAST TO MOVE BACK NORTH. THE GFS IS SHOWING A
FRONTAL TROUGH APPROACHING SOUTH FLORIDA LATE TONIGHT. A 1021 MB
HIGH IS OFF THE CAROLINAS COAST NEAR 35N71W. A DEEP LAYERED
TROUGH IS OVER THE E ATLC WITH A STRONG UPPER LEVEL LOW NEAR
31N26W. AT THE SURFACE...A 1003 MB LOW IS OVER THE E ATLANTIC
NEAR 31N26W. THIS LOW IS COLD-CORE AT THE MOMENT. A COLD FRONT
EXTENDS FROM ALONG 33N22W 26N23W TO 20N30W WHERE IT BECOMES
STATIONARY TO 20N40W. SCATTERED MODERATE CONVECTION IS JUST
AHEAD OF THE FRONT FROM 27N-34N BETWEEN 17W-22W. IN THE DEEP
TROPICS A LARGE ELONGATED UPPER LOW IS NEAR 13N46W. STRONG UPPER
LEVEL WINDS SE OF THE LOW ARE ADVECTING TROPICAL MOISTURE TO THE
NE. DRY AIR ALOFT COVERS FROM 10N-25N BETWEEN 45W-70W.

$$
GR







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