[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150620 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU SEP 15 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURE...

HURRICANE OPHELIA IS CENTERED NEAR 34.5N 76.3W...OR 17 NM SSE OF
CAPE LOOKOUT NORTH CAROLINA...AT 15/0600 UTC MOVING ENE AT 6 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 980 MB. MAXIMUM SUSTAINED
WIND SPEED IS 75 KT WITH GUSTS TO 90 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 HAS HUGGED TO COAST OF THE CAROLINAS
THROUGHOUT THE DAY TODAY AND LOOKS TO CONTINUE THIS TREND FOR
THE NIGHT AND THROUGH THE DAY TOMORROW. A MID/UPPER TROUGH
MOVING INTO THE NE UNITED STATES IS STARTING TO DISRUPT THE
PREVIOUSLY UNIFORM OUTFLOW FORMING W SHEAR OVER OPHELIA. HEAVY
SHOWERS/THUNDERSTORMS REMAIN ALONG THE COASTAL PLAINS OF NORTH
CAROLINA E OF RALEIGH BETWEEN CAPE FEAR AND ALBEMARLE SOUND.
OVER WATER THE ACTIVITY COVERS THE AREA FROM 32.5N-36N W OF 74W
TO INLAND OVER NORTH CAROLINA.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 20W S OF 17N MOVING W 10-15 KT.
WAVE IS ON THE TRAILING EDGE OF AN UPPER TROUGH THAT CONTAINS
DRY AIR AND  A SMALL AMOUNT OF SAHARAN DUST. THUS...NO
ASSOCIATED SHOWERS/CONVECTION.

CENTRAL ATLC TROPICAL WAVE IS ALONG 44W S OF 15N MOVING W 10 KT
WITH A 1009 MB LOW ALONG THE WAVE NEAR 9N. BROAD CURVATURE IS
OBSERVED ON INFRARED SATELLITE IMAGERY. WAVE IS ALSO EMBEDDED IN
A COPIOUS AMOUNT OF TROPICAL MOISTURE PRODUCING A LARGE AREA OF
SCATTERED MODERATE/STRONG CONVECTION WITHIN 90 NM OF LINE
7N41.5W-11.5N46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS WITHIN 60/75 NM OF LINE 10N37.5W-12N44.5W AND 11N47.5W-7N50W.

W ATLC TROPICAL WAVE IS ALONG 54W/55W S OF 17N MOVING W 10-15
KT. WAVE CONTINUES TO DISPLAY A WELL-DEFINED AND SHARP CURVATURE
AND EMBEDDED WITHIN VERY DRY AIR BENEATH THE W EDGE OF AN UPPER
RIDGE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60 NM
OF LINE 14N51W-19N54W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 13N16W 8N27W 9N47W 9N62W. SCATTERED
MODERATE/STRONG CONVECTION IS WITHIN 75 NM OF THE ITCZ AXIS E OF
19W TO THE COAST OF GUINEA BISSAU TO S OF DAKAR SENEGAL.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
WITHIN 150/175 NM OF LINE FROM 8N24W-4N43W.

...DISCUSSION...

GULF OF MEXICO...
STRONG MID/UPPER RIDGE EXTENDS FROM AN UPPER HIGH OVER N CENTRAL
MEXICO ACROSS TEXAS INTO THE GULF NEAR CORPUS CHRISTI TO NEAR
29N86W. THIS IS BRINGING DRY CONTINENTAL AIR OVER THE N GULF N
AN UPPER LEVEL SHEAR AXIS THAT EXTENDS FROM N OF TAMPA FLORIDA
TO NEAR TAMPICO MEXICO. A MID/UPPER LEVEL HIGH IS IN THE BAY OF
CAMPECHE NEAR 19N96W. DIFFLUENCE OVER THE BAY OF CAMPECHE IS
BRINGING SHOWERS/THUNDERSTORMS INLAND OVER S MEXICO...BUT DUE TO
THE DRY AIR OVER THE GULF ONLY ISOLATED SHOWERS ARE ABLE TO FORM
OVER THE AREA. A 1018 MB HIGH IS IN THE N/CENTRAL GULF NEAR
29N88W. THE GULF WILL REMAIN DRY THROUGH THE FIRST OF THE
WEEKEND.

CARIBBEAN...
THE UPPER LEVEL FLOW OVER THE CARIBBEAN CONTINUES TO BE
DOMINATED BY AN UPPER LOW CENTERED S OF JAMAICA NEAR 16N79W. THE
DEEPEST MOISTURE REMAINS LOCATED OVER THE SW CARIBBEAN WHERE
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF
11N FROM OVER COLOMBIA TO CENTRAL AMERICA. ELSEWHERE...THERE ARE
SOME PATCHES OF UPPER MOISTURE MOVING AROUND THE CIRCULATION
ASSOCIATED WITH THE UPPER LOW WITH SCATTERED SHOWERS/
THUNDERSTORMS ARE N OF 20N TO THE COAST OF CUBA FROM 78W-84W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT EH AREA FROM
13N-20N W OF 66W TO OVER CENTRAL AMERICA AND THE YUCATAN. AN
UPPER INVERTED TROUGH FROM CENTRAL VENEZUELA TO THE LEEWARD
ISLANDS IS DRAWING DRY CONTINENTAL AIR OVER THE SE CARIBBEAN AND
THE WINDWARD ISLANDS.

ATLANTIC...
HURRICANE OPHELIA CONTINUES TO DRAW DRY CONTINENTAL AIR ACROSS
NE FLORIDA AND SW GEORGIA TO S OF THE SYSTEM. AN UPPER RIDGE
EXTENDS FROM NEAR OPHELIA S TO THE CENTRAL BAHAMAS. DEEP LAYERED
MID-LATITUDE TROUGH THAT HAD DUG INTO THE CENTRAL ATLC HAS
WEAKENED IN THE LAST 24 HOURS AS THE SUBTROPICAL SURFACE RIDGE
AGAIN TAKES HOLD OF THE REMAINING ATLC WATERS. UPPER LEVEL
TROUGH NOW EXTENDS THROUGH 32N50W SW TO 25N65W AS THE UPPER
RIDGE TO THE S BUILDS NORTHWARD. THE ATTENDANT COLD FRONT
EXTENDS THROUGH 32N41W TO 27N46W. DIFFLUENCE CONTINUES TO
GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM
OF A LINE FROM 23N58W TO BEYOND 32N40W. DRY UPPER AIR AND
STRONG SUBSIDENCE IS N OF THE CONVECTION TO 30N BETWEEN 44W-60W
AND N OF 24N BETWEEN 60W-67W. AN UPPER HIGH IS DEEP IN THE
TROPICS NEAR 10N43W WITH FLOW COVERING THE AREA S OF 22N BETWEEN
29W-55W. THIS RIDGE IS PROVIDING UPPER LEVEL DIFFLUENCE N OF THE
INVERTED TROUGH IN THE CARIBBEAN TO GENERATE SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 20N-24N BETWEEN
59W-65W. THIS UPPER HIGH IS ALSO PROVIDING A DECENT AMOUNT OF
MOISTURE AND DIFFLUENCE ASSOCIATED WITH THE TROPICAL WAVE ALONG
44W. AN UPPER TROUGH CONTINUES TO DIG S OFF THE AFRICAN COAST
FROM AN UPPER LOW OFF THE SW COAST OF PORTUGAL NEAR 36N12W JUST
W OF THE CANARY ISLANDS TO S OF THE CAPE VERDE ISLANDS NEAR
10N27W.

$$
WALLACE


This weather bulletin was brought to you by:
www.nashvilleweather.net