[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 11 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 34W S OF 18N MOVING W 10 KT. LOW/MID
INVERTED-V SIGNATURE IS NOTED ON SATELLITE IMAGERY...WITH A
SWIRL OF LOW CLOUDS NEAR 14N. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 12N-16N BETWEEN 30W-34W.

A LARGE TROPICAL WAVE IS ALONG 60W/61W S OF 24N MOVING W NEAR 10
KT. EARLIER QUIKSCAT PASS SHOWS EVIDENCE OF A CLOSED SURFACE
CIRCULATION. A 1012 MB LOW IS ANALYZED NEAR 13.N59.5W ON THE
1200 UTC MAP. A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION
IS JUST E OF THE WEAK SURFACE LOW FROM 12N-15N BETWEEN 57W-59W.
THE WAVE IS EXPECTED TO MOVE WEST-NORTHWESTWARD ACROSS THE
WINDWARD AND LEEWARD ISLANDS INTO THE EASTERN CARIBBEAN SEA
DURING THE NEXT DAY OR TWO. ENVIRONMENTAL CONDITIONS DO NOT
FAVOR SIGNIFICANT DEVELOPMENT OF THIS SYSTEM WHICH COULD BRING
LOCALLY HEAVY RAIN AND GUSTY WINDS TO THESE ISLANDS. BARBADOS
REPORTED HEAVY RAIN AND SUSTAINED WINDS OF 20 KT THIS MORNING.

TROPICAL WAVE IS ALONG 72W S OF 20N MOVING W 10 KT. BROAD LOW
LEVEL INVERTED-V STRUCTURE IS NOTED ON SATELLITE IMAGERY. THIS
SYSTEM IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
OVER THE LAKE MARACAIBO. ELSEWHERE ISOLATED SHOWERS ARE FOUND.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 1ON14W 6N25W 8N32W 8N40W 12N57W
WIDELY SCATTERED MODERATE CONVECTION IS MAINLY SOUTH OF THE AXIS
FROM 4N-8N EAST OF 20W. CLUSTER OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE INLAND OVER AFRICA FROM 7N-11N BETWEEN
8W-12W.

...DISCUSSION...
GULF OF MEXICO...
DEEP LAYERED TROUGH IS MOVING RAPIDLY EASTWARD ACROSS THE
MISSISSIPPI VALLEY TO OVER THE SE US. THE ASSOCIATED FRONTAL
BOUNDARY IS APPROACHING THE N GULF COAST AND WILL EXTEND FROM
THE FLORIDA PANHANDLE TO THE CENTRAL PORTION OF THE GULF LATE
TONIGHT. AS OF 1500 UTC...A WEAK PRE-FRONTAL TROUGH EXTENDS FROM
SE LOUISIANA TO NE MEXICO. A NARROW LINE OF SHOWERS AND ISOLATED
TSTMS IS RELATED TO THE TROUGH. AN UPPER ANTICYCLONE CENTERED
OVER CENTRAL MEXICO NEAR 20N101W COVERS MOST OF THE GULF AND
CENTRAL AMERICA. AT THE SURFACE...A REMNANT FRONTAL SURFACE
TROUGH EXTENDS THROUGH THE STRAITS OF FLORIDA NEAR 24N80W WWD TO
24N89W WITH ISOLATED SHOWERS/TSTMS MOVING ALONG THE TROUGH AXIS
BETWEEN 81W-84W. THIS SHOWER ACTIVITY MAY REACH SOUTH FLORIDA
TONIGHT. A STRONG COLD FRONT WILL MOVE OFF THE TEXAS AND
LOUISIANA COAST LATE THU AFTERNOON. THIS FRONT PROMISES TO BRING
THE COLDEST AIR OF THE SEASON SO FAR ACROSS THE CENTRAL AND EAST
PARTS OF THE U.S.. TEMPERATURES MAY DROP A FEW DEGREES BELOW
NORMAL ACROSS SOUTH FLORIDA ON SUNDAY.

CARIBBEAN SEA...
AN UPPER RIDGE COVERS THE W-CENTRAL CARIBBEAN WHILE AN UPPER
TROUGH IN THE W ATLC EXTENDS S INTO THE CARIBBEAN ACROSS
HISPANIOLA. THIS UPPER TROUGH WILL APPROACH PUERTO RICO ON
THURSDAY AND MAY INTERACT WITH THE TROPICAL WAVE LOCATED
CURRENTLY ALONG 60/61W...BRINGING THE POTENTIAL OF HEAVY RAIN TO
THE ENCHANTED ISLAND. BROAD RIDGE ANCHORED IN THE TROPICS
COVERING THE CENTRAL ATLC INCLUDES THE FAR E CARIBBEAN. UPPER
DRY AIR DOMINATES MOST OF THE BASIN WITH THE EXCEPTION OF THE SW
CARIBBEAN WHERE THERE ARE ISOLATED SHOWERS/TSTMS. SCATTERED
MODERATE CONVECTION IS ALSO SEEN FROM NORTHERN COLOMBIA TO COSTA
RICA DUE TO THE PRESENCE OF THE ITCZ AXIS. MODERATE TRADE WINDS
OF 10-15 KT WILL CONTINUE TO BLOW ACROSS THE AREA DURING THE
NEXT FEW DAYS.

ATLANTIC OCEAN...
A SHORT WAVE TROUGH ENTERS THE AREA NEAR 31N70W THEN CONTINUES S
INTO THE CARIBBEAN SEA ACROSS HISPANIOLA. A CLUSTER OF MODERATE
TO ISOLATED STRONG CONVECTION IS JUST AHEAD OF THE TROUGH AXIS
FROM 19N-22W BETWEEN 65W-69W. PART OF THIS CONVECTIVE ACTIVITY
EXTENDS SW AFFECTING THE EASTERN PART OF DOMINICAN REPUBLIC.
THE ASSOCIATED WEAKENING FRONTAL BOUNDARY STRETCHES FROM 32N70W
TO 24N80W. A NARROW LINE OF SHOWERS WITH EMBEDDED TSTMS IS
ASSOCIATED WITH THIS FEATURE. BROAD UPPER RIDGE DOMINATES THE
CENTRAL ATLC ANCHORED IN THE TROPICS NEAR 12N46W COVERING THE
AREA FROM 40W-65W. UPPER TROUGH IS OVER THE E ATLC WITH THE AXIS
EXTENDING THROUGH 32N16W SW TO NEAR 15N30W WITH THE ASSOCIATED
COLD FRONT N OF THE REGION. AT THE SURFACE A BROAD SURFACE RIDGE
COVERS THE ATLC E OF 55W WITH A 1023 MB HIGH LOCATED NEAR
29N44W. AN AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS IS FROM
20N-28N BETWEEN 39W-47W ASSOCIATED WITH A SHORT WAVE TROUGH THAT
LIES ALONG 48W.

$$
GR





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