[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 090002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT OCT 08 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND 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 FEATURE...

SUBTROPICAL DEPRESSION TWENTY-TWO HAS FORMED AND IS CENTERED
NEAR 29.1N 60.8W...OR 325 NM SE OF BERMUDA...AT 08/2100 UTC
MOVING WNW 17 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB.
MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/
WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER HEADERS MIATCPAT2/
WTNT32 KNHC FOR MORE DETAILS. THE DEPRESSION IS EMBEDDED WITHIN
A BROAD UPPER LEVEL CYCLONIC GYRE AND HAS GENERATED A MORE
SUBTROPICAL THAN TROPICAL SIGNATURE WITH AN EXPANDED AND
ASYMMETRIC WIND FIELD. SCATTERED MODERATE CONVECTION HAS MOVED W
OF THE CENTER FROM 28N-30N BETWEEN 62W-64W.  SCATTERED SHOWERS/
TSTMS ARE CURRENTLY LOCATED WITHIN A BAND TO THE N AND E OF THE
CENTER FROM 26N-31N BETWEEN 58W-62W. SHOWERS/TSTMS ARE EXPECTED
TO BEGIN SPREADING OVER BERMUDA TONIGHT AND ON SUN AS TROPICAL
MOISTURE IS PULLED NWD.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE IS ALONG 24W S OF 17N MOVING W 10
KT. NO SIGNIFICANT CONVECTION IS NOTED.  THERE IS HOWEVER A NEW
OUTBREAK OF AFRICAN DUST THAT EXTENDS E OF THE WAVE AXIS TO W
AFRICA.

EAST/CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 35W S OF 14N
MOVING W 10-15 KT. THE WAVE IS LOW-AMPLITUDE AND HAS A RATHER
FLAT SIGNATURE YET THERE IS STILL A FAIRLY WELL-DEFINED
CIRCULATION ALONG 8N. ISOLATED MODERATE CONVECTION IS FROM
9N-11N BETWEEN 33W-38W.

CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 50W/51W S OF 20N MOVING
W 5-10 KT. A 1011 LOW IS ON THE WAVE AXIS NEAR 14N51W. DEEP
CONVECTION REMAINS E OF THE WAVE AXIS FROM 12N-18N BETWEEN
46W-50W.

CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 75W S OF 20N MOVING W
10 KT. THE WAVE HAS AN EXTREMELY POOR SIGNATURE AND IS BEING
OBSCURED BY CONVECTION PRODUCED BY UPPER LEVEL DIFFLUENCE.
PATCHES OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
OVER E CUBA AND HISPANIOLA FROM 15N-21N BETWEEN 70W-77W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N16W 8N30W 7N42W 13N50W 16N60W.
SCATTERED MODERATE TO STRONG CONVECTION IS ALONG THE COAST OF W
AFRICA FROM 10N-15N BETWEEN 10W-18W. ISOLATED MODERATE
CONVECTION IS FROM 3N-8N BETWEEN 10W-23W...AND FROM 2N-4N
BETWEEN 23W-41W. SCATTERED MODERATE CONVECTION IS FROM 5N-7N
BETWEEN 43W-46W. WIDELY SCATTERED MODERATE CONVECTION IS FROM
10N-12N BETWEEN 48W-51W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT CONTINUES TO MOVE SLOWLY ACROSS THE GULF WATERS AND
IS ANCHORED BY A 1004 MB LOW LOCATED JUST W OF TAMPA BAY FLORIDA
NEAR 28N83W. THE GRADIENT BEHIND THE FRONT IS RATHER WEAK SO THE
AIR MASS COMING OFF THE CONTINENTAL U.S. IS QUICKLY BEING
MODIFIED BY THE WARM GULF WATERS AND THERE IS LITTLE TEMPERATURE
OR DEWPOINT CHANGE. SCATTERED TO BROKEN LOW CLOUDS EXTEND BEHIND
THE COLD FRONT TO THE TEXAS AND LOUISIANA COASTS.  THE BOUNDARY
EXTENDS FROM THE LOW SW TO THE N YUCATAN COAST NEAR 22N87W THEN
S OF THE CAMPECHE COAST NEAR 18N94W. A STATIONARY SEGMENT
CONTINUES TO LIE INLAND ACROSS MEXICO FROM 18N96W TO 27N107W
WITH OVERCAST LOW AND MIDDLE CLOUDS. THE FRONT ALSO EXTENDS NE
OF THE LOW PAST JACKSONVILLE INTO THE CAROLINAS. SHOWER ACTIVITY
NEAR THE FRONT IS MINIMAL...PARTLY DUE TO STRONG SUBSIDENCE OVER
THE AREA IN ASSOCIATION WITH A LARGE UPPER LOW OVER NE TEXAS
NEAR 32N95W. ISOLATED SHOWERS ARE NOTED ALONG THE MEXICAN COAST
BETWEEN VERACRUZ AND TAMPICO.  EXPECT THE SURFACE LOW TO MOVE
SLOWLY TO NE FLORIDA...AND THE COLD FRONT TO WEAKEN TO A SURFACE
TROUGH AND EXTEND S TO CENTRAL CUBA IN 24 HOURS.

CARIBBEAN...
THE ATMOSPHERE REMAINS QUITE MOIST ACROSS THE CARIBBEAN AS THE
UPPER LOW OVER THE W ATLANTIC NEAR 24N62W ADVECTS ATLANTIC
MOISTURE INTO THE N CARIBBEAN BETWEEN THE LEEWARD ISLANDS AND W
CUBA...AND PUSHES IT S TO 13N.  CONVECTION IS PRIMARILY BEING
FORCED BY A FEW LOW-LEVEL BOUNDARIES. A SURFACE TROUGH EXTENDS
FROM W CUBA TO THE GULF OF HONDURAS AND IS TRIGGERING SCATTERED
MODERATE CONVECTION FROM 15N-21N BETWEEN 81W-87W.  A TROPICAL
WAVE IS OVER THE CENTRAL CARIBBEAN...SEE ABOVE.  LOW LEVEL SPEED
CONVERGENCE IS OVER THE LEEWARD ISLANDS PRODUCING SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION FROM 13N-19N BETWEEN
60W-68W.  EXPECT CONTINUED CONVECTION OVER THE CARIBBEAN E OF
88W FOR THE NEXT 24 HOURS.

WEST/CENTRAL ATLANTIC...
A PRE-FRONTAL TROUGH LIES ALONG 78W...AHEAD OF THE COLD FRONT
MOVING ACROSS THE SOUTHEAST U.S.  AN UPPER LEVEL RIDGE IS
LOCATED OVER THE TROUGH ALONG 76W AND IS PROVIDING A FAVORABLY
DIFFLUENT ENVIRONMENT OVER THE BAHAMAS.  A DEEP UPPER LEVEL
TROUGH IS LOCATED ALONG 62W WITH AN EMBEDDED UPPER LOW NEAR
24N62W...AND THIS FEATURE IS WHAT LED TO THE DEVELOPMENT OF
SUBTROPICAL DEPRESSION TWENTY-TWO. ASIDE FROM CONVECTION NEAR
THE DEPRESSION...ISOLATED MODERATE CONVECTION HAS ALSO FORMED
FARTHER E FROM 20N-26N BETWEEN 45W-55W.

EAST ATLANTIC...
A LARGE UPPER LEVEL HIGH IS CENTERED WITHIN THE TROPICS NEAR
14N42W.  FURTHER E... A DEEP-LAYERED TROUGH IS OVER THE E
ATLANTIC WITH AXIS ALONG 32N21W 17N29W. AN UPPER LOW IS
EMBEDDED WITHIN THE TROUGH NEAR 33N20W AND ODDLY ENOUGH A TIGHT
CORE OF CONVECTION HAS DEVELOPED WITHIN 45 NM OF THE
CENTER...GIVING THE SYSTEM AN ALMOST TROPICAL APPEARANCE. A
SURFACE TROUGH EXTENDS S AND SE OF THE LOW FROM THE WESTERN
CANARY ISLANDS SW TO 23N30W AND IS ALONG THE LEADING EDGE OF A
STRATOCUMULUS FIELD. ISOLATED SHOWERS MAY MOVE ACROSS THE CANARY
AND MADEIRA ISLANDS...BUT THIS SYSTEM IS MOSTLY COLD-CORE AND IS
NOT EXPECTED TO BECOME TROPICAL OVER THE COLDER WATERS OF THE NE
ATLC. FARTHER E...THE DEEP TROUGH IS ADVECTING TROPICAL MOISTURE
ALL THE WAY UP TO THE STRAITS OF GIBRALTAR AND SCATTERED
MODERATE CONVECTION HAS FORMED OVER MOROCCO AND WESTERN SAHARA
FROM 23N-32N BETWEEN 8W-15W.

$$
FORMOSA


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