[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 201157 AAA
TWDAT

TROPICAL WEATHER DISCUSSION...UPDATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 20 2008

...UPDATE ON CRISTOBAL...

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 1045 UTC.

...SPECIAL FEATURES...

TROPICAL STORM CRISTOBAL AT 20/1200 UTC IS NEAR 34.1N 76.8W OR
ABOUT 35 NM SOUTH-SOUTHWEST OF CAPE LOOKOUT NORTH CAROLINA AND
ABOUT 90 NM SOUTHWEST OF CAPE HATTERAS NORTH CAROLINA. CRISTOBAL
IS MOVING NE AT 5 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS
1007 MB. MAXIMUM SUSTAINED WINDS ARE NOW 45 KT WITH GUSTS TO 55
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. THE OVERALL
ORGANIZATION OF THE SYSTEM CONTINUES TO SLOWLY EVOLVE AS
INDICATED BY THE LATEST SATELLITE IMAGERY AND RADAR DATA FROM
THE WILMINGTON NC WSR-88D. CRISTOBAL IS FORECAST TO SLOWLY
STRENGTHEN OVER THE NEXT FEW DAYS AS THE CENTER OF THE STORM
MOVES ALONG THE COAST OF NORTH CAROLINA SUNDAY. RAINFALL AMOUNTS
OF 3 TO 5 INCHES ARE EXPECTED ALONG THE COAST OF NORTH CAROLINA
WITH ISOLATED HEAVIER AMOUNTS. AN AREA OF SCATTERED MODERATE
CONVECTION IS S OF THE CENTER FROM 31N-33N BETWEEN 77W-78W.

THE CENTER OF TROPICAL STORM BERTHA AT 20/0900 UTC IS NEAR 48.5N
38.9W OR ABOUT 670 MILES...1080 KM...EAST-NORTHEAST OF CAPE RACE
NEWFOUNDLAND MOVING NORTHEAST OR 35 DEGREES 26 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 985 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 60 KT WITH GUSTS TO 75 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 RETAINING TROPICAL STORM INTENSITY EVEN AS IT
CONTINUES TO PLOW WELL NORTH OF 45 DEGREES LATITUDE AND MOVE
OVER COOLER WATERS. BERTHA IS EXPECTED TO BECOME AN
EXTRATROPICAL CYCLONE WITHIN 12 HOURS AND THEN BE ABSORBED BY A
LARGER SYSTEM IN LESS THAN THREE DAYS. THUS FAR BERTHA'S LONG
LIFE AS A TROPICAL CYCLONE MAKES BERTHA BY SEVERAL DAYS THE
LONGEST LIVED JULY TROPICAL CYCLONE. PRESENTLY THE STRONGEST
CONVECTION IS N OF THE CENTER. SCATTERED MODERATE CONVECTION IS
FROM 48N-50N BETWEEN 38W-40W.

STRONG TROPICAL WAVE IS ALONG 82W S OF 21N WITH AN ASSOCIATED
GALE LOW NEAR 15N82W 1006 MB. GALE CONDITIONS ARE FROM 16N-20N
BETWEEN 77W-82W AS CONFIRMED BY RECONNAISSANCE AIRCRAFT.
SCATTERED STRONG CONVECTION IS W OF JAMAICA FROM 15N-20N BETWEEN
79W-83W. ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR THIS
SYSTEM TO BECOME A TROPICAL CYCLONE WITHIN THE NEXT DAY OR TWO
AS IT MOVES WEST NORTHWESTWARD AT 15 KT. REGARDLESS OF
DEVELOPMENT...LOCALLY HEAVY RAINS WILL AFFECT PORTIONS OF
CUBA...AND THE CAYMAN ISLANDS TODAY. INTERESTS IN THE
NORTHWESTERN CARIBBEAN SEA AND THE YUCATAN PENINSULA SHOULD
CONTINUE TO MONITOR THE PROGRESS OF THIS SYSTEM.

THE WESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 94W SOUTH OF 21N
MOVING WEST ABOUT 12 KT. THE WAVE EXTENDS FROM THE BAY OF
CAMPECHE TO THE ERN PACIFIC. ASSOCIATED 1006 MB LOW IS LOCATED
OVER THE E PACIFIC NEAR 13N94W. HEAVY RAINS OVER PORTIONS OF EL
SALVADOR... GUATEMALA...AND SE MEXICO COULD CAUSE
LIFE-THREATENING FLASH FLOODS AND MUDSLIDES OVER THE NEXT DAY OR
SO. IN ADDITION... CONDITIONS APPEAR CONDUCIVE FOR POSSIBLE
TROPICAL CYCLONE FORMATION WITHIN THE NEXT 48 HOURS IN THE E
PACIFIC BASIN.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 34W SOUTH OF 13N MOVING W AT 15 KT. THIS
IS A LOW AMPLITUDE WAVE WITH WIDELY SCATTERED MODERATE
CONVECTION CONFINED TO THE ITCZ FROM 3N-7N BETWEEN 30W-40W.

TROPICAL WAVE IS ALONG 58W SOUTH OF 20N MOVING WEST 17 KT. THIS
WAVE IS SOMEWHAT LESS EVIDENT IN THE SATELLITE IMAGERY THAN THE
OTHER WAVES NOTED WITH ONLY AN INVERTED V SIGNATURE INDICATED IN
THE STRATOCUMULUS FIELD WITH NO DEEP CONVECTION ALONG THE WAVE
AXIS ITSELF. SCATTERED SHOWERS ARE W OF THE WAVE AXIS OVER THE
WINDWARD ISLANDS FROM 10N-15N BETWEEN 60W-65W.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 12N16W 10N25W 7N40W 10N60W.
BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION
...SCATTERED MODERATE TO STRONG CONVECTION IS ALONG THE COAST OF
W AFRICA FROM 5N-13N BETWEEN 10W-20W. SCATTERED MODERATE
CONVECTION IS FROM 10N-12N BETWEEN 20W-25W. ISOLATED MODERATE
CONVECTION IS FROM 6N-8N BETWEEN 48W-54W.

...DISCUSSION...

THE GULF OF MEXICO...
A 1018 MB HIGH IS CENTERED OVER THE E GULF OF MEXICO NEAR 29N85W
PRODUCING MOSTLY FAIR WEATHER. A WEAK SURFACE RIDGE EXTENDS W TO
E TEXAS. WINDS ARE PREDOMINATELY SELY 5-10 KT. A TROPICAL WAVE
IS OVER THE BAY OF CAMPECHE S OF 21N. SCATTERED MODERATE
CONVECTION IS FROM 18N-20N BETWEEN 95W-98W. IN THE UPPER
LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER S TEXAS NEAR
30N100W PRODUCING SLY FLOW OVER THE W GULF W OF 93W. ANOTHER
UPPER LEVEL LOW IS CENTERED OVER W CUBA NEAR 22N84W MOVING W.
CYCLONIC FLOW IS OVER THE E GULF AND W CUBA E OF 91W. EXPECT
CONVECTION TO BE OVER W CUBA...THE YUCATAN CHANNEL...AND THE
SOUTH CENTRAL GULF OF MEXICO WITHIN 24 HOURS DUE TO THE TROPICAL
WAVE PRESENTLY OVER W CARIBBEAN. ALSO EXPECT CONVECTION S
MEXICO...AND THE BAY OF CAMPECHE DUE TO THE TROPICAL WAVE
PRESENTLY ALONG 94W OVER THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
A STRONG TROPICAL WAVE WITH GALE FORCE WINDS IS OVER THE
CARIBBEAN SEA. SEE ABOVE. ANOTHER TROPICAL WAVE IS APPROACHING
THE LESSER ANTILLES PRODUCING SCATTERED SHOWERS OVER THE
WINDWARD ISLANDS. IN ADDITION...SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS INLAND OVER N COLOMBIA FROM 7N-10N BETWEEN
74W-77W. IN THE UPPER LEVELS...THE UPPER LEVEL LOW OVER W CUBA
IS PRODUCING CYCLONIC FLOW IS OVER THE NW CARIBBEAN. ANOTHER
UPPER LEVEL LOW IS OVER THE LEEWARD ISLANDS NEAR 18N64W WITH
STRONG SUBSIDENCE. THE REMAINDER OF THE CARIBBEAN HAS
CONSIDERABLE UPPER LEVEL MOISTURE. EXPECT THE TROPICAL WAVES TO
MOVE W OVER THE NEXT 24 HOURS WITH CONVECTION.

THE ATLANTIC OCEAN...
T.S. CRISTOBAL IS OFF THE NORTH CAROLINA COAST AND IS NO LONGER
PRODUCING CONVECTION OFF THE COAST OF FLORIDA. A 1021 MB HIGH IS
OVER THE W ATLANTIC NEAR 34N66W. A SURFACE TROUGH IS OVER THE
CENTRAL ATLANTIC ALONG 32N55W 28N60W 27N63W. A 1016 MB LOW HAS
DEVELOPED ON THE TROUGH AT 27N63W. SCATTERED SHOWERS ARE WITHIN
60 NM OF THE TROUGH...AND SCATTERED MODERATE CONVECTION IS FROM
27N-28N BETWEEN 61W-64W. A 1029 HIGH IS CENTERED WELL N OF THE
AZORES NEAR 48N20W. A RIDGE AXIS EXTENDS SW TO 40N30W 34N40W
31N50W. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS OVER THE W
ATLANTIC NEAR 27N64W. A SMALL UPPER LEVEL LOW IS FURTHER E NEAR
27N50W. AN UPPER LEVEL RIDGE IS OVER THE E ATLANTIC E OF 30W.

$$
FORMOSA


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