[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 061050
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 06 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...SPECIAL FEATURE....

THE CENTER OF TROPICAL STORM BERTHA IS NEAR 17.3N 43.2W AT
06/0900 UTC MOVING WEST 19 KT. THIS POSITION ALSO IS ABOUT
2110 KM EAST OF THE NORTHERN LEEWARD ISLANDS. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1000 MB. THE MAXIMUM SUSTAINED WIND
SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE READ THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
AND THE LATEST PUBLIC ADVISORY UNDER MIATCPAT2/WTNT32 FOR MORE
DETAILS. SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 17N TO
18N BETWEEN 43W AND 44W. POSSIBLE SHOWERS ELSEWHERE FROM
15N TO 21N BETWEEN 39W AND 47W. THE LONG-TERM FORECAST FOR
BERTHA IS TO MOVE WEST-NORTHWEST DURING THE FORECAST
PERIOD...AND POSSIBLY BECOME A HURRICANE AFTER THE NEXT
THREE DAYS. SEA SURFACE TEMPERATURES WILL BE FAVORABLE FOR
DEVELOPMENT. EVERYTHING WILL DEPEND ON THE WIND SHEAR.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 25W/26W SOUTH OF 20N
MOVING WEST 15 KT. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND
POSSIBLE PRECIPITATION FROM 5N TO 12N BETWEEN 23W AND 28W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 68W SOUTH OF 24N
MOVING WEST 20 TO 25 KT. LOW CLOUDS ARE MOVING CYCLONICALLY
AROUND THE WAVE NO DEEP CONVECTIVE PRECIPITATION.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 83W SOUTH OF 25N MOVING
WEST 15 KT. THIS WAVE STRETCHES FROM JUST WEST OF THE FLORIDA
KEYS TO CUBA TO COSTA RICA. LINGERING SHOWERS ARE NEAR THE WAVE.
A MIDDLE TO UPPER LEVEL TROUGH PASSES OVER CUBA TO 19N78W TO TO
11N77W. SOME OF THE PRECIPITATION MAY BE RELATED TO THE WAVE AND
SOME OF THE PRECIPITATION MAY BE RELATED TO THE OTHER MIDDLE TO
UPPER LEVEL FEATURES.

A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 95W SOUTH OF 20N
MOVING WEST 15 TO 20 KT. THIS WAVE STRETCHES FROM THE
SOUTHWESTERN CORNER OF THE GULF OF MEXICO. EARLIER ISTHMUS OF
TEHUANTEPEC PRECIPITATION HAS WEAKENED. WIDELY SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE SOUTH OF
22N BETWEEN THE YUCATAN PENINSULA AND THE MEXICO COAST.

...THE ITCZ...
12N16W 8N25W 17N36W 14N39W 6N50W 5N56W. STRONG SHOWERS AND
THUNDERSTORMS IN ONE CELL WITHIN A 15 NM RADIUS OF 9N14.5W.
ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 5N TO 10N BETWEEN
AFRICA AND 30W...AND FROM THE EQUATOR TO 12N BETWEEN 30W AND 53W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS IN
NORTHERN MEXICO SPREADING CYCLONIC FLOW ACROSS MEXICO NORTH OF
23N. SHOWERS AND THUNDERSTORMS ARE FROM 19N TO 22N...AND FROM
20N TO 22N ALONG THE MEXICO EAST COAST. AN UPPER LEVEL RIDGE
FROM THE UPPER TEXAS COAST/SOUTHWESTERN LOUISIANA BORDER INTO
THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO IS SENDING UPPER
LEVEL ANTICYCLONIC FLOW ACROSS PRACTICALLY THE ENTIRE GULF OF
MEXICO. THE FLOW DOES NOT BECOME CYCLONIC UNTIL REACHING 84W
FROM WEST TO EAST. A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH
30N80W TO A CYCLONIC CIRCULATION CENTER NEAR 28N80W JUST OFF THE
FLORIDA EAST COAST...TO THE CUBA COAST ALONG 80W...INTO THE
CARIBBEAN SEA NEAR 17N79W. POSSIBLE SHOWERS IN THE ATLANTIC
OCEAN AND THE CARIBBEAN SEA NORTH OF 17N WEST OF 77W. WIDELY
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS
ARE FROM 20N TO 25N BETWEEN 67W AND 70W UNDER UPPER LEVEL
ANTICYCLONIC FLOW AND POSSIBLY IN AN AREA OF ENOUGH UPPER
LEVEL DIFFLUENT WIND FLOW IN ORDER TO HELP THE DEVELOPMENT
OF CONVECTIVE PRECIPITATION.

THE CARIBBEAN SEA...

UPPER LEVEL ANTICYCLONIC FLOW FROM A FEW SOURCES COVERS THE WEST
OF 70W. SOME ANTICYCLONIC FLOW COMES FROM A WESTERN GULF OF
MEXICO RIDGE...SOME COMES FROM A SEPARATE SMALL UPPER LEVEL
RIDGE IN THE SOUTHWESTERN CORNER OF THE AREA. AN INVERTED MIDDLE
TO UPPER LEVEL RIDGE IS ALONG 69W IN DRY AIR/SUBSIDENCE.
CONVECTIVE DEBRIS CLOUDS AND MOSTLY LINGERING SHOWERS ARE WEST
OF 75W.

THE ATLANTIC OCEAN...

BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA NORTH
OF 25N BETWEEN 60W AND 74W. MIDDLE LEVEL CYCLONIC FLOW IS CUTTING
INTO THE NORTHEASTERN CORNER OF THE SECTION OF UPPER LEVEL
ANTICYCLONIC FLOW. AN UPPER LEVEL TROUGH PASSES THROUGH 32N49W
TO 27N55W TO 22N60W. NO DEEP CONVECTIVE PRECIPITATION ACCOMPANIES
THIS TROUGH. A MIDDLE TO UPPER LEVEL TROUGH EXTENDS THROUGH
31N23W TO 26N34W. A SURFACE RIDGE EXTENDS FROM A 1026 MB HIGH
PRESSURE CENTER NEAR 33N58W TO 28N77W TO THE FLORIDA EAST COAST
NEAR 28N.

$$

MT




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