[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 232339
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT SEP 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
HURRICANE HELENE IS CENTERED NEAR 38.0N 44.4W OR ABOUT 945
MILES...1520 KM...WEST OF THE AZORES AT 23/2100 UTC MOVING
EAST-NORTHEAST AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
970 MB. MAXIMUM SUSTAINED WIND SPEED IS 80 KT WITH GUSTS TO 100
KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/ WTNT23 KNHC FOR MORE DETAILS. SATELLITE IMAGERY
SHOWED THAT A SMALL AREA OF DEEP CONVECTION DEVELOPED OVER AND
JUST NORTH OF THE CENTER.  SCATTERED MODERATE CONVECTION IS FROM
38N-39N BETWEEN 43W-45W.  A BAND OF SCATTERED MODERATE
CONVECTION IS NW OF THE CENTER FROM 38N-44N BETWEEN 44W-47W.
HELENE IS BARELY MAINTAINING TROPICAL CHARACTERISTICS AND IS
EXPECTED TO TRANSFORM INTO AN EXTRATROPICAL CYCLONE IN THE NEAR
FUTURE.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 43W S OF 16N. A 109 MB LOW IS BEHIND THE
WAVE AXIS NEAR 18N41N.  BROAD LOW/MID LEVEL CYCLONIC ROTATION
COVERS A LARGE AREA WITH CLUSTERS OF SCATTERED MODERATE/STRONG
CONVECTION FROM 16N-21N BETWEEN 36W-43W. SLOW DEVELOPMENT OF
THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS IT MOVES
TOWARD THE NORTHWEST AT ABOUT 10 MPH. MEANWHILE...THE TROPICAL
WAVE WILL CONTINUE TO MOVE WWD AT 10-15 KT.

TROPICAL WAVE IS ALONG 60W S OF 20N MOVING W 10 KT. THE WAVE
SHOWS AN INVERTED-V CLOUD PATTERN ON SATELLITE PICTURES.
SCATTRED SHOWERS AND ISOLATED TSTMS ARE AFFECTING THE WINDWARD
ISLANDS FROM 12N-17N BETWEEN 57W-62W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N15W 8N25W 14N38W 10N50W 13N60W.
OUTSIDE FROM THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
5N-8N BETWEEN 16W-25W.  SCATTERED MODERATE CONVECTION IS FROM
11N-13N BETWEEN 30W-32W.

...DISCUSSION...
GULF OF MEXICO...
THE GULF OF MEXICO HAS SLY RETURN FLOW DUE TO SURFACE RIDGING.
ISOLATED MODERATE CONVECTION IS OVER W CUBA FROM 22N-24N BETWEEN
81W-86W.  FAIR WEATHER DOMINATES THE REMAINDER OF THE GULF.  A
COLD FRONT IS OVER CENTRAL TEXAS MOVING SE.  IN THE UPPER
LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER THE SE GULF OF
MEXICO NEAR 23N88W WITH STRONG SUBSIDENCE EXCEPT NEAR THE
CONVECTION MENTIONED ABOVE.  EXPECT THE COLD FRONT TO ENTER THE
NW GULF OF MEXICO SUNDAY MORNING WITH CONVECTION.  THE REMAINDER
OF THE GULF WILL HAVE CONTINUED SE SURFACE FLOW AND FAIR
WEATHER.

CARIBBEAN SEA...
MODERATE TRADEWINDS ARE NOTED OVER THE CARIBBEAN SEA.  SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER EL
SALVADOR...GUATEMALA...AND S MEXICO FROM 13N-19N BETWEEN
88W-94W.  ISOLATED MODERATE CONVECTION IS OVER HISPANIOLA...AND
CUBA...BETWEEN 71W-80W.  IN THE UPPER LEVELS... CYCLONIC FLOW IS
OVER THE NW CARIBBEAN DUE TO THE UPPER LEVEL LOW OVER THE SE
GULF OF MEXICO.  THE REMAINDER OF THE CARIBBEAN HAS NELY TO ELY
UPPER LEVEL FLOW WITH STRONG SUBSIDENCE. EXPECT MORE CONVECTION
OVER THE W CARIBBEAN AND CENTRAL AMERICA OVER THE NEXT 24
HOURS... AS WELL AS MORE SHOWERS OVER THE E CARIBBEAN DUE TO THE
TROPICAL WAVE.

ATLANTIC OCEAN...
A 1023 MB HIGH IS OVER THE W ATLANTIC NEAR 35N65W PRODUCING FAIR
WEATHER.  A SURFACE TROUGH IS S OF HURRICANE HELENE ALONG 32N44W
26N56W.  SCATTERED SHOWERS ARE WITHIN 60 NM OF THE TROUGH.  A
1019 MB HIGH IS OVER THE E ATLANTIC NEAR 32N30W.  IN THE UPPER
LEVELS... AN UPPER LEVEL HIGH IS OVER THE W ATLANTIC NEAR
28N73W.  A SMALL UPPER LEVEL LOW IS CENTERED N OF THE LEEWARD
ISLANDS NEAR 20N63W.  ANOTHER UPPER LEVEL LOW IS CENTERED
NEAR 20N50W.  A LARGE HIGH IS CENTERED OVER THE CAPE VERDE
ISLANDS NEAR 18N25W.

$$
FORMOSA




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