[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE SEP 13 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...

HURRICANE OPHELIA IS CENTERED NEAR 32.6N 78.1W...OR 110 NM S OF
WILMINGTON NORTH CAROLINA...AT 13/2130 UTC MOVING NNW 3 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 985 MB. MAXIMUM SUSTAINED
WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
AND THE PUBLIC ADVISORY UNDER HEADERS MIATCPAT1/WTNT31 KNHC FOR
MORE DETAILS.  RECONNAISSANCE AIRCRAFT WITH STEPPED-FREQUENCY
MICROWAVE RADIOMETER WINDS FOUND HURRICANE FORCE SURFACE WINDS
IN OPHELIA...THUS THE STORM WAS UPGRADED.  OPHELIA'S STRUCTURE
HAS GREATLY IMPROVED SINCE YESTERDAY AND IT APPEARS THAT THE
HURRICANE HAS FINALLY BEEN ABLE TO SHED ITSELF OF DRY UPPER
LEVEL AIR THAT HAD WRAPPED AROUND.  A LARGE 30 NM DIAMETER EYE
STILL REMAINS.  UPPER LEVEL OUTFLOW IS RELATIVELY CIRCULAR.  A
FEEDER BAND WITH SQUALLY WINDS AND SCATTERED MODERATE CONVECTION
IS INLAND OVER EASTERN SOUTH CAROLINA AND SOUTHERN NORTH
CAROLINA. PRESENTLY SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS FROM 31N-36N BETWEEN 75W-80W.  THIS ACTIVITY WILL
CONTINUE TO SPREAD INLAND AS OPHELIA SLOWLY HEADS N ALONG THE
NORTH CAROLINA COAST.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE IS ALONG 36W S OF 17N MOVING W 10
KT. THE WAVE IS STILL LOW LATITUDE BUT HAS BEGUN TO ACQUIRE A
STRONGER LOW-LEVEL CIRCULATION AS IT BECOMES MORE EMBEDDED IN
THE TRADE WIND FLOW REGIME. SCATTERED MODERATE CONVECTION IS
FROM 10N-14N BETWEEN 36W-40W.

CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 48W S OF 21N MOVING W 10
KT. THE WAVE CONTINUES TO DISPLAY A WELL-DEFINED AND SHARP
CIRCULATION...BUT IT CONTINUES TO BE AFFECTED BY MODERATE SWLY
SHEAR THAT IS KEEPING ALL CONVECTION E OF THE CENTER.  SCATTERED
MODERATE CONVECTION IS FROM 13N-16N BETWEEN 45W-48W.

WEST CARIBBEAN TROPICAL WAVE IS ALONG 84W S OF 20N MOVING W 15
KT. THE WAVE HAS AN IMPROVED CIRCULATION NOTED OVER CENTRAL
AMERICA AND S OF NICARAGUA.  SCATTERED MODERATE TO STRONG
CONVECTION IS FROM 11N-16N BETWEEN 82W-88W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N16W 9N20W 7N35W 10N40W 11N50W
9N60W.  WIDELY SCATTERED MODERATE CONVECTION IS FROM 3N-7N
BETWEEN 32W-35W.  WIDELY SCATTERED MODERATE IS ALSO FROM 5N-10N
BETWEEN 35W-45W.

...DISCUSSION...

GULF OF MEXICO...
1019 MB HIGH IS OVER THE NE GULF OF MEXICO NEAR 27N88W AND IS
FORECAST TO REMAIN STATIONARY FOR THE NEXT 24 HOURS.  FAIR
WEATHER AND LIGHT WINDS DOMINATE THE GULF.  SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION IS NOTED...HOWEVER...OVER THE
YUCATAN PENINSULA FROM 18N-22N BETWEEN 87W-91W.   IN THE UPPER
LEVELS...A CYCLONIC CIRCULATION IS OVER S MEXICO NEAR 18N99W.
FURTHER E...A RIDGE AXIS EXTENDS FROM THE YUCATAN PENINSULA TO N
FLORIDA.  EXPECT CONTINUED CONVECTION OVER THE YUCATAN PENINSULA
OVER THE NEXT 24 HOURS.

CARIBBEAN...
A TROPICAL WAVE IS OVER CENTRAL AMERICA WITH ASSOCIATED
CONVECTION.  A 1008 MB LOW IS OVER N COLOMBIA NEAR 8N76W.
MODERATE TRADEWINDS COVERS THE REMAINDER OF THE SEA.
HISPANIOLA...E CUBA...AND JAMAICA HAVE SCATTERED MODERATE
CONVECTION OVER HIGHER ELEVATIONS DUE TO OROGRAPHIC LIFTING.
WIDELY SCATTERED MODERATE CONVECTION IS ALSO OVER PANAMA AND THE
SW CARIBBEAN FROM 7N-13N BETWEEN 79W-82W.  IN THE UPPER LEVELS...
A CYCLONIC CIRCULATION IS CENTERED OVER JAMAICA NEAR 18N77W.
CYCLONIC FLOW IS W OF 70W.  FURTHER E...A RIDGE AXIS EXTENDS
FROM THE W ATLANTIC AT 28N70W TO THE LEEWARD ISLANDS NEAR
17N60W.  EXPECT CONTINUED CONVECTION OVER CENTRAL AMERICA FROM
PANAMA TO THE YUCATAN PENINSULA OVER THE NEXT 24 HOURS.

WEST ATLANTIC...
TROPICAL STORM OPHELIA IS SLOWLY MOVING N TOWARDS THE CAROLINA
COAST. A SURFACE TROUGH IS OVER THE N BAHAMAS ALONG 28N75W
25N80W WITH SCATTERED SHOWERS WITHIN 30 NM.  A 1020 MB HIGH IS E
OF OPHELIA NEAR 29N64W.  A SURFACE TROUGH IS EXPECTED TO DEVELOP
NEAR PUERTO RICO OVER THE NEXT 24 HRS AND THEN MOVE NW OVER THE
BAHAMAS...WHICH COULD INCREASE THE CHANCE OF SHOWERS/TSTMS OVER
THE AREA THROUGH THE WEEKEND.

CENTRAL/EAST ATLANTIC...
A STATIONARY FRONT IS OVER THE CENTRAL ATLANTIC ALONG 32N36W
24N50W 20N60W.  SCATTERED SHOWERS ARE WITHIN 30 NM OF THE
FRONT.  SCATTERED MODERATE CONVECTION IS ALSO FROM 23N-25N
BETWEEN 58W-60W.  A 1022 MB HIGH IS OVER THE E ATLANTIC NEAR
35N21W.  EASTERLY FLOW IS FROM 20N-30N E OF 35W.  IN THE UPPER
LEVELS...AN UNSEASONABLY STRONG UPPER LEVEL TROUGH HAS DUG DOWN
OVER THE SUBTROPICAL WATERS N OF 22N BETWEEN 40W-70W BUT APPEARS
RELATIVELY STATIONARY AT THE MOMENT. A CYCLONIC CIRCULATION IS
LOCATED NEAR 21N45W AT THE NRN END OF THE CENTRAL ATLC TROPICAL
WAVE AND IS BEING PULLED NWD AHEAD OF THE UPPER TROUGH.  AN
ANTICYCLONIC CIRCULATION HAS DEVELOPED DEEP IN THE TROPICS
NEAR 13N35W AND IS PROVIDING A FAIRLY DECENT ENVIRONMENT ABOVE
THE TROPICAL WAVE ALONG 36W. ELSEWHERE...AN UPPER TROUGH LIES
JUST OFF THE AFRICAN COAST ALONG 32N11W TO THE CANARY ISLANDS TO
19N23W AND APPEARS TO BE INCREASING UPPER LEVEL OUTFLOW FARTHER
S OFF THE COAST OF GUINEA.

$$
FORMOSA


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