[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 312356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 31 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM CHANTAL IS CENTERED NEAR 41.7N 61.2W AT 31/2100
UTC OR ABOUT 200 NM SOUTH-SOUTHEAST OF HALIFAX NOVA SCOTIA AND
ABOUT 460 NM SOUTHWEST OF CAPE RACE NEWFOUNDLAND MOVING RAPIDLY
NE AT 23 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB.
MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC FOR ADDITIONAL DETAILS. CHANTAL CONTINUES
TO SHOW A CURVED BAND STRUCTURE BUT IS EXPECTED TO BEGIN THE
TRANSITION TO EXTRATROPICAL AS IT MOVES OVER COOLER WATER.
SCATTERED MODERATE CONVECTION IS N OF THE LOW LEVEL CENTER
WITHIN 75 TO 120 NM OF LINE FROM 42N61W TO 47N57W. AN OUTER
RAINBAND EXTENDS S OF THE CENTER WITH SCATTERED SHOWERS/
THUNDERSTORMS WITHIN 60 NM IF LINE FROM 28N60W TO 42N57W.

A 1010 MB LOW NEAR 12N51W IS ABOUT 485 NM E OF THE S WINDWARD
ISLANDS. SYSTEM HAS BECOME LESS ORGANIZED WITH ANY DEEP
CONVECTION WELL AWAY FROM THE LOW LEVEL CENTER. HOWEVER...THIS
SYSTEM STILL HAS THE POTENTIAL FOR FURTHER DEVELOPMENT. CLUSTERS
OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 7N-11N
BETWEEN 47W-55W AND FROM 11N-14N BETWEEN 53W-56W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 35W/363W S OF 20N MOVING W 15 KT. WEAK
LEVEL INVERTED-V CURVATURE COVERING THE AREA FROM 32W-40W. ANY
DEEP CONVECTION IS WITHIN THE ITCZ.

TROPICAL WAVE IS OVER THE LESSER ANTILLES ALONG 60W/61W MOVING W
15-20 KT. WEAK LOW LEVEL INVERTED-V CURVATURE COVERS THE AREA
FROM 58W-65W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER
THE LESSER ANTILLES S OF GUADELOUPE TO INLAND OVER SOUTH AMERICA
BETWEEN 59W-62W.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN AND SW ATLC IS CURVED
FROM 24N70W THROUGH 15N71W TO INLAND OVER SOUTH AMERICA TO NEAR
7N70W. THE N PORTION OF THE WAVE OVER THE SW ATLC MAY BECOME
SEPARATED FROM THE MAIN BODY OF THE WAVE OVER THE NEXT 12 TO 24
HOURS. THIS WAVE IS EMBEDDED WITHIN SOME RATHER DRY STABLE AIR
ESPECIALLY OVER THE CARIBBEAN...THUS ONLY AFTERNOON
THUNDERSTORMS ARE BEING GENERATED OVER THE GREATER ANTILLES.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N15W 9N31W 13N48W 10N53W 10N59W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG  CONVECTION ARE
FROM 6N-15N E OF 24W TO THE COAST OF W AFRICA AND FROM 6N-11N
BETWEEN 35W-42W.

...DISCUSSION...
GULF OF MEXICO...
DEEP LAYERED TROUGH EXTENDS OVER THE E US DIPPING INTO THE W
ATLC AND NE FLORIDA WITH THE ASSOCIATED COLD FRONT IN THE W ATLC
AND TO OVER THE N GULF COAST STATES GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS INTO THE GULF N OF A LINE FROM
FORT MYERS FLORIDA TO THE LOUISIANA/TEXAS BORDER. RAIN WITH
EMBEDDED SCATTERED THUNDERSTORMS COVER THE FLORIDA PENINSULA.
MOST OF THE GULF IS DOMINATED BY AN UPPER RIDGE AXIS THAT
EXTENDS FROM AN UPPER HIGH OVER CENTRAL TEXAS ESE TO THE FLORIDA
PENINSULA NEAR LAKE OKEECHOBEE...THUS DRYING OUT THE REMAINDER
OF THE GULF. A WEAK SURFACE RIDGE EXTENDS ACROSS THE CENTRAL
BAHAMAS THROUGH A WEAKENING 1017 MB HIGH OVER THE W TIP OF CUBA
TO THE NW GULF.

CARIBBEAN...
CONDITIONS ACROSS THE MAJORITY OF THE CARIBBEAN SEA ARE TRANQUIL
THIS EVENING IN RESPONSE TO ABUNDANT DRY STABLE AIR ALOFT.
WEAK UPPER LEVEL INVERTED TROUGH EXTENDS ACROSS THE CENTRAL
CARIBBEAN FROM COLOMBIA TO HISPANIOLA GIVING THE E CARIBBEAN SE
UPPER FLOW AND W CARIBBEAN NE UPPER FLOW. AFTERNOON
THUNDERSTORMS THAT WERE GENERATED OVER THE GREATER ANTILLES FROM
PUERTO RICO TO E CUBA ARE BEGINNING TO DIE OUT WITH REMAINING
ISOLATED SHOWERS/THUNDERSTORMS ACROSS THE N/CENTRAL CARIBBEAN N
OF 17N FROM 67W-78W. THE ITCZ AXIS EXTENDS INTO THE E PACIFIC
REGION ACROSS PANAMA AND COSTA RICA GIVING THE FAR SW CARIBBEAN
ISOLATED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90
NM ALONG THE COAST OF COSTA RICA AND NICARAGUA S OF 13N. THE
ACTIVITY OVER THE LESSER ANTILLES IS ASSOCIATED WITH THE
TROPICAL WAVE IN THE AREA. THE REMAINDER OF THE CARIBBEAN
REMAINS SHOWER FREE THIS EVENING.

ATLANTIC...
SEE SPECIAL FEATURES FOR INFORMATION ON TROPICAL STORM CHANTAL
AND THE 1010 MB LOW IN THE W TROPICAL ATLC. DEEP LAYERED TROUGH
EXTENDS FROM OVER THE E US INTO THE W ATLC N OF 28N W OF 72W TO
OVER NE FLORIDA WITH AN ASSOCIATED WEAK COLD FRONT ENTERING THE
REGION NEAR 32N75W TO ACROSS NE FLORIDA NEAR JACKSONVILLE TO
INLAND OVER THE N GULF COAST STATES. SCATTERED SHOWERS/
THUNDERSTORMS ARE S OF 31N AND W OF A LINE FROM 31N68W TO THE N
BAHAMAS NEAR 25N77W. RAIN WITH EMBEDDED SCATTERED THUNDERSTORMS
COVER THE FLORIDA PENINSULA. THE UPPER RIDGE FROM THE GULF OF
MEXICO EXTENDS ACROSS CENTRAL FLORIDA NEAR LAKE OKEECHOBEE INTO
THE W ATLC ALONG 28N76W TO BEYOND 32N69W ENHANCING THE ACTIVITY
ABOVE. THE REMAINDER OF THE ATLC IS DOMINATED BY BENIGN UPPER
LEVEL FEATURES MOSTLY DUE TO THE DRY STABLE AIR THAT COVERS THE
ATLC E OF 70W. THE EXCEPTION IS A WEAKENING 1010 MB LOW IN THE E
TROPICAL ATLC NEAR 13N28W WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 90 NM W OF THE LOW FROM 12-14N. THIS LOW IS
BEING OVERTAKEN BY THE NEXT TROPICAL WAVE/LOW EMERGING OFF THE
COAST OF AFRICA AND WILL BE INTRODUCED ON THE 0000 UTC SURFACE
ANALYSIS. OTHERWISE...A SURFACE RIDGE ALSO CONTINUES TO DOMINATE
THE ATLC ANCHORED BY A 1026 MB W OF THE AZORES.

$$
WALLACE







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