[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED OCT 04 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.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 42 S OF 18N WITH AN EXPOSED 1010 MB LOW
ON THE WAVE NEAR 12N MOVING W 10-15 KT. THIS LOW IS FORECAST TO
DISSIPATE DURING THE NEXT 24 HRS. SCATTERED SHOWERS ARE
ASSOCIATED WITH THE LOW/WAVE. MOST OF THE CONVECTIVE ACTIVITY IS
WITHIN THE ITCZ.

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 52W S OF 15N MOVING W
NEAR 10 KT. SOME CYCLONIC TURNING IS NOTED IN THE LOW TO MID
CLOUD FIELD. SCATTERED MODERATE CONVECTION FROM 10N-12N BETWEEN
50W-52W.

A TROPICAL WAVE EXTENDS FROM HISPANIOLA TO WESTERN VENEZUELA
MOVING W 10-15 KT. A SLIGHT INVERTED V PATTERN IS NOTED. THE
WAVE IS ENHANCING THE SHOWER/TSTM ACTIVITY OVER HISPANIOLA...
PUERTO RICO AND WESTERN VENZUELA. A DIFLUENT PATTERN ALOFT IS
SUPPORTING THE DEVELOPMENT OF THIS CONVECTIVE ACTIVITY. THE SAN
JUAN DOPPLER RADAR SHOWS NUMEROUS SHOWERS WITH EMBEDDED TSTMS
MOVING UNDER A SELY WIND FLOW OVER PUERTO RICO AND THE U.S.
VIRGIN ISLANDS. WEATHER CONDITIONS WILL GRADUALLY IMPROVE OVER
THESE ISLANDS AS THE TROPICAL WAVE MOVES AWAY FROM THIS AREA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N14W 5N25W 11N38W 10N50W 8N58W.
OUTSIDE OF THE CONVECTION NEAR THE TROPICAL WAVES...PATCHES OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE OVER THE COAST
OF AFRICA AND ADJACENT ATLC WATERS FROM 5N-13N EAST OF 20W.
SIMILAR CONVECTION IS FROM 8N-11N BETWEEN 37W-50W. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE MAINLY SOUTH OF THE ITCZ AXIS
FROM 1N-7N BETWEEN 20W-35W.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER TROUGH LIES ALONG THE COAST OF TEXAS AND MEXICO. BROAD
UPPER RIDGE EXTENDS ACROSS THE YUCATAN PENINSULA INTO THE GULF.
A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH THESE FEATURES IS
GENERATING A LARGE AREA OF CLOUDINESS WITH SCATTERED MODERATE
CONVECTION THAT COVERS MOST OF THE GULF. THERE ARE NO SIGNS OF
ORGANIZATION...AND UPPER-LEVEL WINDS ARE CURRENTLY NOT CONDUCIVE
FOR FURTHER DEVELOPMENT. CLUSTERS OF MODERATE TO ISOLATED STRONG
CONVECTION HAVE ALSO DEVELOPED OVER THE YUCATAN PENINSULA AND
NORTHERN GUATEMALA. HIGH CLOUDS FROM THESE SHOWER/TSTM ACTIVITY
ARE STREAMING TO THE E AROUND THE RIDGING OVER THE E GULF. THE
NE CORNER OF THE GULF AND THE STATE OF FLORIDA ARE UNDER DRY MID
TO UPPER AIR WITH TROUGHING JUST OFF THE EAST COAST. A 1023 MB
SURFACE HIGH LOCATED OVER THE GEORGIA/ALABAMA BORDER IS
PRODUCING MODERATE TO STRONG WINDS OF 15-20 KT ACROSS MUCH OF
THE GULF. THIS IS EXPECTED TO PERSIST THE NEXT COUPLE OF DAYS.

CARIBBEAN SEA...
A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE CARIBBEAN SEA. THE
UPPER RIDGE THAT EXTENDS ACROSS THE YUCATAN PENINSULA ALSO
COVERS THE NW CARIBBEAN AND NORTHERN CENTRAL AMERICA. AN UPPER
LEVEL TROUGH OVER THE WEST ATLC EXTENDS S INTO THE BASIN ALONG
74W/75W WITH AN UPPER RIDGE OVER THE E CARIBBEAN. UPPER
DIFFLUENCE BETWEEN THIS TROUGH AND THE RIDGE OVER THE ERN
CARIBBEAN IS HELPING TO SUPPORT THE SCATTERED SHOWERS/TSTMS OVER
THE GREATER ANTILLES. THIS ACTIVITY IS ALSO BEING ENHANCED BY
THE TROPICAL WAVE MOVING THROUGH THE AREA. ITCZ MOISTURE IS
GENERATING SCATTERED MODERATE CONVECTION OVER COSTA
RICA...PANAMA AND THE SW CARIBBEAN. 10-20 KT TRADE WINDS BLOW
ACROSS THE CARIBBEAN WITH THE STRONGEST WINDS JUST OFF THE
COLOMBIAN COAST.

ATLANTIC OCEAN...
UPPER LEVEL TROUGH EXTENDS OVER THE W ATLC INTO THE CARIBBEAN
SEA ALONG THE BAHAMAS AND EASTERN CUBA. THE ASSOCIATED SURFACE
TROUGH RUNS FROM 31N66W TO 22N72W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS MAINLY WITHIN 130/150 NM BEHIND THE TROUGH
AXIS. PART OF THIS SHOWER ACTIVITY IS AFFECTING THE SOUTHERN
BAHAMAS. THERE ARE NO SIGNS OF ORGANIZATION...AND UPPER-LEVEL
WINDS ARE CURRENTLY NOT CONDUCIVE FOR FURTHER DEVELOPMENT. THE
COMBINATION OF THE TROUGH AND A HIGH PRESSURE CENTER LOCATED
NORTH OF THE AREA IS PRODUCING MODERATE NE WINDS OVER SOUTH
FLORIDA AND THE STRAIT OF FLORIDA. SEVERAL LOCATIONS ALONG THE
SE COAST REPORTED GUSTY WINDS OF 20 KT DURING THE AFTERNOON.
SCATTERED SHOWERS AND TSTMS ARE MOVING UNDER THE NE WIND FLOW
ACROSS THE STRAIT OF FLORIDA. ANOTHER BREEZY DAY IS EXPECTED
TOMORROW. THE UPPER RIDGE FROM THE CARIBBEAN EXTENDS ACROSS
PUERTO RICO AND THE W/CENTRAL ATLC ALONG 68W. A DEEP LAYER LOW
IS NEAR 31N35W WHERE A WEAK 1016MB SURFACE LOW IS ALSO ANALYZED.
THIS LOW IS EXPECTED TO WEAKEN. AN ELONGATED UPPER TROUGH
EXTENDS FROM THE UPPER LOW ALONG 25N36W 18N50W. ABUNDANT UPPER
LEVEL MOISTURE IS AHEAD OF THE UPPER TROUGH FROM THE DEEP
TROPICS ALL THE WAY NE AND N OVER THE E ATLC. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE SEEN NORTH OF 24N BETWEEN 23W-32W. AN
UPPER HIGH IS BETWEEN THE CANARY ISLANDS AND THE W COAST OF
AFRICA. AT THE SURFACE...THE ERN ATLC IS ALSO DOMINATED BY THE
SOUTHERN PORTION OF A 1029MB SURFACE HIGH LOCATED JUST N OF THE
MADEIRA ISLANDS.

$$
GR




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