[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 191810
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI JUL 18 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...SPECIAL FEATURES...

THE CENTER OF HURRICANE BERTHA AT 19/1500 UTC IS NEAR 43.1N
45.4W MOVING NORTHEAST OR 35 DEGREES 22 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 989 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 65 KT WITH GUSTS TO 80 KT. PLEASE READ THE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
AND THE PUBLIC ADVISORY UNDER MIATCPAT2/WTNT32 KNHC FOR MORE
DETAILS. BERTHA IS STILL A HURRICANE EVEN THOUGH IT IS NOW WELL
NORTH OF 40 DEGREES NORTH LATITUDE AND MOVING OVER RATHER CHILLY
SEA-SURFACE TEMPERATURES. BERTHA'S LONG LIFE AS A TROPICAL
CYCLONE PROBABLY IS NEARING ITS END SINCE IT IS GAINING LATITUDE
SO QUICKLY. THE OFFICIAL FORECAST CALLS FOR BERTHA TO BE AN
EXTRATROPICAL CYCLONE WITHIN ABOUT 24 HOURS AND THEN BE ABSORBED
BY A LARGER SYSTEM IN LESS THAN THREE DAYS.

TROPICAL STORM CRISTOBAL JUST FORMED OFF THE COAST OF SOUTH
CAROLINA DURING THE LAST HOUR. ITS CENTER AT 19/1800 UTC
IS NEAR 32.8N 78.3W OR ABOUT 100 MILES/160 KM EAST OF CHARLESTON
SOUTH CAROLINA AND ABOUT 225 MILES/365 KM SOUTHWEST OF CAPE
HATTERAS NORTH CAROLINA. CRISTOBAL IS MOVING NORTHEAST 6 KT.
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 35 KT WITH GUSTS TO 45 KT. PLEASE
READ THE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT3/
WTNT33 KNHC FOR MORE DETAILS. SOME STRENGTHENING OF CRISTOBAL
IS FORECAST DURING THE NEXT FEW DAYS. THE CENTER OF THE STORM
IS EXPECTED TO MOVE ALONG THE COASTS OF SOUTH AND NORTH CAROLINA
TODAY AND TOMORROW. RAINFALL AMOUNTS OF 3 TO 5 INCHES ARE
EXPECTED ALONG THE COASTS OF NORTH CAROLINA AND NORTHERN SOUTH
CAROLINA...WITH ISOLATED HEAVIER AMOUNTS IN NORTHEASTERN SOUTH
CAROLINA AND SOUTHEASTERN NORTH CAROLINA. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 30N TO 34N
BETWEEN 75W AND 80W.

THE WESTERN CARIBBEAN SEA TROPICAL WAVE THAT WAS ALONG 78W
TWENTY FOUR HOURS AGO NOW IS ALONG 89W SOUTH OF 21N MOVING
WEST ABOUT 15 KT. THE WAVE RUNS FROM THE NORTHERN YUCATAN
PENINSULA TO THE EASTERN PACIFIC OCEAN...CROSSING OVER
EL SALVADOR. ALL THE STRONG PRECIPITATION WITH THIS WAVE
IS IN THE EASTERN PACIFIC OCEAN FROM 11N TO 13N BETWEEN
92W AND 93W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 53W/54W SOUTH OF 20N
MOVING WEST 15 TO 20 KT. THIS WAVE IS COMPARATIVELY MUCH LESS
EVIDENT IN THE VISIBLE SATELLITE THAN THE OTHER WAVES.
NO DEEP CONVECTIVE PRECIPITATION ACCOMPANIES THIS WAVE.

...THE ITCZ...
17N16W 8N27W 5N39W 10N63W. THE SMALL SECTION OF THE ATLANTIC
OCEAN AND THE SOUTHEASTERN CARIBBEAN SEA WITH SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 9N TO 13N BETWEEN
56W AND 66W IS TO THE SOUTH OF THE BASE OF A MIDDLE TO UPPER
LEVEL ATLANTIC OCEAN 19N56W-TO-CARIBBEAN SEA 13N64W TROUGH.
SCATTERED STRONG THUNDERSTORMS WITHIN A 30 NM RADIUS OF 8N25W...
FROM 7N TO 8N BETWEEN 26W AND 27W...AND FROM 7N TO 8N BETWEEN
29W AND 30W. WIDELY SCATTERED MODERATE SHOWERS AND ISOLATED
STRONG THUNDERSTORMS FROM 4N TO 7N BETWEEN 36W AND 40W.
ISOLATED MODERATE SHOWERS FROM 1N TO 5N BETWEEN 40W AND 50W.

...DISCUSSION...

THE GULF OF MEXICO...
MIDDLE TO UPPER LEVEL CYCLONIC FLOW COVERS THE SOUTHEASTERN
CORNER OF THE AREA THANKS TO THE MIDDLE TO UPPER LEVEL TROUGH
THAT EXTENDS FROM THE BAHAMAS ACROSS CUBA INTO THE WESTERN
CARIBBEAN SEA. A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM EAST
TEXAS TO A CYCLONIC CIRCULATION CENTER ALONG THE TEXAS/MEXICO
BORDER NEAR 28N100W TO A SECOND POSSIBLE CYCLONIC CENTER NEAR
25N101W...TO 22N103W. AN UPPER LEVEL RIDGE COVERS THE REST OF
THE GULF OF MEXICO IN BETWEEN THE TWO AREAS OF CYCLONIC FLOW.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL TROUGH IS IMMEDIATELY TO THE WEST OF THE
78W TROPICAL WAVE...EXTENDING FROM THE BAHAMAS...ACROSS CUBA
INTO THE WESTERN AND SOUTHWESTERN CARIBBEAN SEA. ANOTHER MIDDLE
TO UPPER LEVEL TROUGH EXTENDS FROM THE ATLANTIC OCEAN NEAR 19N56W
INTO THE SOUTHEASTERN CARIBBEAN SEA NEAR 13N64W. SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 9N TO 13N
BETWEEN 56W AND 66W IS TO THE SOUTH OF THE BASE THE TROUGH.

THE ATLANTIC OCEAN...
A SURFACE TROUGH DEVELOPED WELL TO THE SOUTH OF HURRICANE
BERTHA. THE TROUGH PASSES THROUGH 32N53W TO 27N60W TO A 1015 MB
LOW PRESSURE CENTER NEAR 27N65W. THE TROUGH CONTINUES FROM THE
LOW PRESSURE CENTER TO 27N67W AND 30N71W. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 27N TO 28N
BETWEEN 62W AND 64W. ISOLATED MODERATE SHOWERS ARE WITHIN
15 TO 30 NM ON EITHER SIDE OF THE TROUGH BETWEEN THE LOW CENTER
AND 68W. CONVECTIVE DEBRIS AND POSSIBLE SHOWERS ARE WITHIN
30 NM ON EITHER SIDE OF THE TROUGH EAST OF THE LOW CENTER.
A MIDDLE TO UPPER LEVEL TROUGH IS CONNECTED BY ONE CYCLONIC
CIRCULATION CENTER NEAR 27N50W TO 22N50W TO 19N56W TO 13N64W
IN THE SOUTHEASTERN CARIBBEAN SEA. THIS TROUGH IS EMBEDDED
IN/SURROUNDED BY DRY AIR IN SUBSIDENCE.

$$
MT


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