[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 232342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IN THE TROPICAL ATLC IS ALONG 51W/52W S OF 15N
MOVING W 10-15 KT.  WAVE HAS GOTTEN BETTER-DEFINED IN SATELLITE
PICTURES WITH A CLEAR V-SHAPE.  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 CONVECTION IS FROM 7N-9N BETWEEN 52W-55W.

...ITCZ...
ITCZ AXIS IS ALONG 9N10W 7N30W 9N50W 9N55W 14N68W 9N80W.
ISOLATED MODERATE CONVECTION IS FROM 6N-8N BETWEEN 18W-20W...
FROM 6N-9N BETWEEN 27W-30W...AND FROM 7N-10N BETWEEN 43W-48W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 10N-12N
BETWEEN 68W-71W.  SCATTERED MODERATE CONVECTION IS FROM 8N-11N
BETWEEN 77W-82W.

...DISCUSSION...
GULF OF MEXICO...
FAIR WEATHER HIGH PRESSURE RIDGING DOMINATES THE GULF OF
MEXICO.  WARMER-THAN-AVERAGE WEATHER CONTINUES IN THE WESTERN
GULF STATES WITH MODERATE TEMPERATURES 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.  ANTICYCLONIC
CIRCULATION IS SITTING OVER THE CENTRAL GULF OF MEXICO NEAR
24N88W. STRONG SUBSIDENCE IS 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 34N66W WITH TROF S
INTO THE AREA THRU THE SE BAHAMAS INTO FAR E CUBA .  THIS LOW
WILL 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 32N55W TO E CUBA NEAR 21N75W AND
DISSIPATING AS A TROUGH OVER THE NW CARIBBEAN TO 21N84W.
ISOLATED SHOWERS ARE WITHIN 120 NM OF THE FRONT N OF 25N.
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...
UPPER LEVEL TROUGH CONTINUES FROM E CUBA THRU JAMAICA TO AN
UPPER LEVEL LOW OVER N NICARAGUA AT 13N87W.  WEAK SURFACE TROUGH
FROM A DISSIPATING COLD FRONT IS PRODUCING A FEW SHOWERS WITHIN
90 NM S OF CUBA.  THE WEATHER W OF THE UPPER LEVEL 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 CONVECTION IS 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...
ANTICYCLONIC CIRCULATION DOMINATES THE AREA W OF 30W WITH A
CENTER NEAR 21N53W AND RIDGE AXIS EXTENDING SW TO GUADELOUPE...
AND ANOTHER RIDGE AXIS EXTENDING NE TO BEYOND 32N45W.  A 1005 MB
SURFACE LOW IS NEAR 26N52W MOVING NE AT 15 KT.  THIS LOW IS
STRONGLY SHEARED FROM THE W WITH SCATTERED MODERATE CONVECTION
FROM 21N-29N BETWEEN 42W-52W.  THE REST OF THE SUBTROPICAL ATLC
AND DEEP TROPICS IS QUIET WITH A DEEPENING UPPER LEVEL TROUGH
ALONG 22W 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.

$$
FORMOSA



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