[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141212
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED SEP 14 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...

HURRICANE OPHELIA IS CENTERED NEAR 33.4N 77.8W 70 NM S OF
WILMINGTON NORTH CAROLINA AND 125 NM SOUTHWEST OF CAPE LOOKOUT
NORTH CAROLINA...AT 14/1200 UTC MOVING N AT 4 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 980 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.
OPHELIA CONTINUES TO BECOME BETTER ORGANIZED THIS MORNING. THE
ASSOCIATED DEEP CONVECTION HAS BECOME A LITTLE RAGGED OVER THE
LAST 6 HOURS DUE TO INTERACTION WITH LAND. HEAVY
SHOWERS/THUNDERSTORMS COVERS THE AREA FROM 31.5N-35N BETWEEN
75.5W-80W INCLUDING SE NORTH CAROLINA AND NE SOUTH CAROLINA.
WITH THE WEAK STEERING CURRENTS...OPHELIA COULD LINGER OVER THE
AREA TOADY...SLOWLY MOVING OUT OF SOUTH CAROLINA TONIGHT INTO
THU BUT REMAINING ALONG THE NORTH CAROLINA COASTAL AREA THROUGH
THU NIGHT.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE ALONG 39W/40W S OF 17N MOVING W 15 KT.
BROAD WAVE WITH A LOW-LEVEL CURVATURE IS OBSERVED ON VISIBLE
SATELLITE IMAGERY. WAVE IS ALSO EMBEDDED IN A COPIOUS AMOUNT OF
TROPICAL MOISTURE PRODUCING SCATTERED MODERATE/STRONG CONVECTION
FROM THE ITCZ AXIS N TO 14N BETWEEN 32W-41W.

CENTRAL ATLC TROPICAL WAVE TILTED ALONG 7N51W 15N51W 21N49W
MOVING W 10-15 KT. WAVE CONTINUES TO DISPLAY A WELL-DEFINED AND
SHARP CURVATURE...BUT IT CONTINUES TO BE AFFECTED BY MODERATE
SW SHEAR THAT IS KEEPING ALL CONVECTION WELL TO THE E.

W CARIBBEAN TROPICAL WAVE HAS MOVED INTO THE S GULF OF MEXICO
ALONG 92W S OF 20N MOVING W 15 KT. WAVE IS ACROSS S MEXICO INTO
THE E PACIFIC WITH THE CURVATURE EASILY DEFINED IN THE E PACIFIC
REGION. THIS WAVE IS INTERACTING WITH AN UPPER LEVEL HIGH OVER
THE YUCATAN PENINSULA PUSHING THE SCATTERED MODERATE/ISOLATED
STRONG CONVECTION OVER THE W BAY OF CAMPECHE S OF 20.5N W OF
93.5W. STRONGER CONVECTION IS WELL INTO THE E PACIFIC REGION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 13N15W 8N27W 12N45W 11N62W.
SCATTERED STRONG CONVECTION IS WITHIN 120 NM OF THE AXIS FROM
17W-21W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 5N TO THE ITCZ AXIS E OF 27W TO THE
COAST OF AFRICA AND FROM 1N TO THE ITCZ AXIS BETWEEN 35W-48W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH/SHEAR AXIS EXTENDS ACROSS THE SE UNITED
STATES NEAR ALABAMA TO THE W BAY OF CAMPECHE AND IS DRAWING SOME
TROPICAL MOISTURE N OVER THE E GULF AHEAD OF A BUILDING UPPER
RIDGE THAT EXTENDS FROM THE YUCATAN PENINSULA NE TO THE CENTRAL
FLORIDA PENINSULA. DIFFLUENCE OVER THE YUCATAN AND BAY OF
CAMPECHE IS ENHANCING THE SHOWERS/THUNDERSTORMS ASSOCIATED WITH
THE TROPICAL WAVE. SCATTERED SHOWERS FROM 22N-27N BETWEEN
86W-95W. WEAK 1017 MB HIGH IS IN THE S/CENTRAL GULF NEAR 25N87W.
THIS PATTERN IS EXPECTED TO BE MAINTAINED UNTIL A DRIER SURGE OF
AIR MOVES IN LATE THU.

CARIBBEAN...
THE UPPER LEVEL FLOW OVER THE CARIBBEAN IS DOMINATED BY A LARGE
UPPER LOW CENTERED S OF JAMAICA NEAR 17N78W. THE DEEPEST
MOISTURE REMAINS LOCATED OVER THE SW CARIBBEAN WHERE CLUSTERS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 15N W OF 76W
TO INLAND OVER PANAMA TO NICARAGUA. ELSEWHERE...THERE ARE SOME
PATCHES OF UPPER MOISTURE MOVING AROUND THE CIRCULATION
ASSOCIATED WITH THE UPPER LOW...BUT LOW-LEVEL CONDITIONS ARE
GENERALLY TOO DRY FOR WIDESPREAD CONVECTION. SCATTERED SHOWERS
ARE WITHIN 120 NM OF LINE FROM W/CENTRAL CUBA TO THE GULF OF
HONDURAS. ISOLATED SHOWERS DOT THE E CARIBBEAN N OF 14N E OF
74W.

WEST ATLANTIC...
HURRICANE OPHELIA CONTINUES TO DRAW DRY CONTINENTAL AIR ACROSS
GEORGIA TO S OF THE SYSTEM. AN UPPER RIDGE EXTENDS FROM NEAR
OPHELIA SSE TO THE MONA PASSAGE. DEEP LAYERED MID-LATITUDE
TROUGH DIGS INTO THE CENTRAL ATLC IS BREAKING THE SUBTROPICAL
SURFACE RIDGE DOWN FORMING A WEAK RIDGE EXTENDING FROM
A 1020 MB HIGH NEAR BERMUDA SW TO THE S/CENTRAL BAHAMA ISLANDS.

CENTRAL/EAST ATLANTIC...
THE UNSEASONABLY STRONG UPPER LEVEL TROUGH HAS DUG DOWN OVER
THE SUBTROPICAL WATERS N OF 18N BETWEEN 38W-68W AND REMAINS NEAR
STATIONARY. ATTENDANT STATIONARY FRONT EXTENDS THROUGH 32N36W
ALONG 24N50W TO 22N62W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 120/150 NM OF EITHER SIDE OF THE FRONT
FROM 23N-31N. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
WITHIN 90 NM W OF THE FRONT N OF 31N AND WITHIN 120/150 NM
EITHER SIDE OF THE FRONT W OF 55W. A SECOND SURGE IN THE FORM
OF AN UPPER SHORTWAVE TROUGH WITH AN ATTENDANT COLD FRONT ALONG
32N NEAR 53W. AN UPPER HIGH IS DEEP IN THE TROPICS NEAR 8N43W
WITH A RIDGE EXTEND NNE TO 27N35W AND IS PROVIDING A FAIRLY
DECENT AMOUNT OF MOISTURE AND DIFFLUENCE ASSOCIATED WITH THE
TROPICAL WAVE ALONG 39W/40W. AN UPPER TROUGH IS DIGGING S OFF
THE AFRICAN COAST ALONG 32N16W JUST W OF THE CANARY ISLANDS
TO S OF THE CAPE VERDE ISLANDS NEAR 12N26W.

$$
WALLACE


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