[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT 23 OCT 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLC 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IN THE TROPICAL ATLC IS ALONG 50W/51W S OF 16N
MOVING W 10-15 KT.  WAVE HAS GOTTEN BETTER-DEFINED IN SATELLITE
PICTURES WITH A CLEAR V-SHAPE AND INCREASING CONVECTION.  THE
GFS GENERALLY WEAKENS THE WAVE AS IT APPROACHES THE LESSER
ANTILLES BUT SUGGESTS GREATER RAIN CHANCES THAN AVERAGE IN THE
WINDWARD ISLANDS FOR MON.  SCATTERED MODERATE WITHIN 75 NM OF
THE AXIS BETWEEN 6N-12N.

...ITCZ...
ITCZ AXIS IS ALONG 8N13W 5N30W 9N46W 10N62W.   ISOLATED MODERATE
IS WITHIN 75 NM OF LINES 5N11W 4N39W AND 9.5N18W 7N36W.  WIDELY
SCATTERED MODERATE FROM 6N-10N BETWEEN 41W-49W.

...DISCUSSION...
GULF OF MEXICO...
TODAY APPEARS TO BE A CARBON COPY OF YESTERDAY EXCEPT FOR THE
LACK OF A FRONTAL ZONE IN THE AREA. MUCH WARMER-THAN-AVERAGE
WEATHER CONTINUES IN THE WESTERN GULF STATES WITH SOME MODERATE
IN FLORIDA.  GENERALLY ELY WINDS ARE PRESENT IN THE E GULF WITH
MORE MOIST SLY WINDS IN THE W GULF AHEAD OF THE NEXT FRONT OVER
TEXAS.  MID/UPPER RIDGE IS SITTING OVER N-CENTRAL MEXICO WITH
STRONG SUBSIDENCE LIMITING SHOWER ACTIVITY IN THE GULF.  TEXAS
COLD FRONT IS FORECAST TO MOVE INTO THE GULF ON SUN THOUGH IT IS
EXPECTED TO HANG UP IN THE NW GULF OVERNIGHT WITH INCREASING
RAIN ALONG THE GULF COAST.  FRONT SHOULD MOVE THROUGH ALL OF
FLORIDA BY MON WITH ANOTHER SHOT OF DRIER AIR.

SUBTROPICAL ATLC W OF 60W...
POWERFUL DEEP-LAYERED LOW IS SPINNING NEAR 35N68W WITH TROF S
INTO THE AREA THRU THE SE BAHAMAS INTO FAR E CUBA .  THIS LOW
WILL HAVE TO BE WATCHED FOR SIGNS OF SUBTROPICAL DEVELOPMENT AS
IT COULD LOSE ITS FRONTAL CHARACTERISTICS OVER THE NEXT DAY OR
TWO WHILE STILL OVER WARM WATER.  IN ANY EVENT THIS LOW IS
DRIVING A COLD FRONT THRU THE TROPICS FROM 32N61W TO E CUBA NEAR
21N76W AND DISSIPATING AS A TROUGH OVER THE NW CARIBBEAN THRU
THE YUCATAN CHANNEL.  ISOLATED SHOWERS ARE NEAR AND BEHIND THE
FRONT FROM N OF 24N BETWEEN 60W-65W.  OTHERWISE ISOLATED SHOWERS
ARE OCCURRING IN THE NLY FLOW BEHIND THE FRONT OVER THE NW
BAHAMAS ACROSS E FLORIDA AND THE N COAST OF CUBA.

CARIBBEAN SEA...
MID-LATITUDE TROUGH CONTINUES FROM E CUBA THRU JAMAICA INTO A
FORMING MID-LEVEL LOW ACROSS N NICARAGUA.  WEAK TROUGH FROM A
DISSIPATING COLD FRONT IS PRODUCING A FEW SHOWERS WITHIN 90 NM S
OF CUBA.  THE WEATHER W OF THE TROUGH AXIS IS RELATIVELY QUIET
BUT THE CENTRAL/E CARIBBEAN IS MUCH MORE UNSETTLED.  SURFACE
TROUGH REMAINS FROM COSTA RICA TO PUERTO RICO WITH TSTMS ALONG
AND AHEAD OF THE BOUNDARY.  WIDELY SCATTERED MODERATE S OF 15N
BETWEEN 70W-79W WITH SIMILAR CONVECTION N OF 16N BETWEEN
62W-68W.  FLOODING IS POSSIBLE IN PUERTO RICO AND THE LEEWARD
ISLANDS AS THIS MOISTURE-LADEN TROUGH REMAINS.  ANOTHER WET DAY
IS LIKELY TOMORROW BEFORE THE HEAVIEST RAIN SHIFTS E ON MON
FOR PUERTO RICO.  MID/UPPER RIDGE POKES INTO THE AREA FROM ABOUT
GUADELOUPE TO COSTA RICA WITH THE DISTURBED WEATHER ON THE NW
PERIPHERY OF THE HIGH.

SUBTROPICAL ATLC E OF 60W AND TROPICAL ATLC...
AMPLIFYING HIGH IN THE MID/UPPER LEVELS DOMINATES THIS AREA W OF
30W WITH A CENTER NEAR 18N55W AND RIDGE AXIS FROM GUADELOUPE TO
23N46W THEN N TO 32N46W.   A 1007 MB SURFACE LOW HAS FORMED NEAR
25N54W MOVING NE 15 KT.  THIS LOW IS STRONGLY SHEARED FROM THE W
WITH SCATTERED MODERATE CONVECTION FROM 21N-29N BETWEEN 44W-52W.
FARTHER SW... THE TAIL END OF A SURFACE TROUGH FROM PUERTO RICO
ENDS NEAR 20N60W WITH SCATTERED MODERATE CONVECTION WITHIN 75 NM
OF THE TROUGH.  THE REST OF THE SUBTROPICAL ATLC AND DEEP
TROPICS IS QUIET WITH A DEEPENING TROUGH ALONG 22N NEAR AND N OF
THE CAPE VERDES.  STRONG SUBSIDENCE IS KEEPING THE AREA FREE OF
SIGNIFICANT CONVECTION EXCEPT THE ITCZ REGION.  THIS TROUGH/
RIDGE/TROUGH PATTERN IN THE SUBTROPICAL ATLC LOOKS TO BE FAIRLY
STABLE WITH NO CHANGES SEEN THRU MID-WEEK.

$$
BLAKE


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