[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 200558
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN JUL 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM BERTHA AT 20/0300 UTC IS NEAR 45.7N
41.8W OR ABOUT 545 MILES...875 KM...EAST OF CAPE RACE
NEWFOUNDLAND MOVING NORTHEAST OR 40 DEGREES 21 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 990 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 40 DEGREES LATITUDE AND MOVE
OVER COOLER WATERS. BERTHA IS EXPECTED TO BECOME AN
EXTRATROPICAL CYCLONE WITHIN 24 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 47N-51N BETWEEN 38W-44W.

TROPICAL STORM CRISTOBAL AT 20/0300 UTC IS NEAR 33.4N 77.5W OR
ABOUT 45 MILES... 70 KM...SOUTHEAST OF CAPE FEAR NORTH CAROLINA
AND ABOUT 170 MILES...270 KM...SOUTHWEST OF CAPE HATTERAS NORTH
CAROLINA. CRISTOBAL IS MOVING NORTHEAST 5 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WINDS ARE
NOW 40 KT WITH GUSTS TO 50 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 TO ISOLATED STRONG CONVECTION IS S OF THE CENTER FROM
31N-33N BETWEEN 77W-79W.

STRONG TROPICAL WAVE IS ALONG 81W S OF 21N WITH AN ASSOCIATED
GALE LOW NEAR 15N81W 1006 MB. GALE CONDITIONS ARE FORECAST FROM
15N-20N BETWEEN 75W-82W AS CONFIRMED BY RECONNAISSANCE AIRCRAFT.
SCATTERED STRONG CONVECTION IS W OF JAMAICA FROM 14N-19N BETWEEN
78W-82W. 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 92W93W 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 13N92W. 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 33W SOUTH OF 13N MOVING W AT 15 KT. THIS
IS A LOW AMPLITUDE WAVE WITH SCATTERED MODERATE CONVECTION
CONFINED TO THE ITCZ FROM 4N-8N BETWEEN 29W-34W.

TROPICAL WAVE IS ALONG 57W 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.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 12N16W 10N26W 6N40W 10N60W.
BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION
...SCATTERED MODERATE TO STRONG CONVECTION IS OFF THE COAST OF W
AFRICA FROM 8N-12N BETWEEN 15W-19W. ISOLATED MODERATE CONVECTION
IS FROM 5N-7N BETWEEN 37W-39W...AND FROM 7N-9N BETWEEN 44W-47W.

...DISCUSSION...

THE GULF OF MEXICO...
A 1018 MB HIGH IS CENTERED OVER THE E GULF OF MEXICO NEAR 27N85W
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 TO
ISOLATED STRONG CONVECTION IS FROM 18N-20N BETWEEN 94W-96W. 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 22N784W
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 92W/93W 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...WIDELY SCATTERED MODERATE
CONVECTION IS INLAND OVER N COLOMBIA FROM 4N-10N BETWEEN
72W-77W. SIMILAR CONVECTION IS INLAND OVER NICARAGUA AND
HONDURAS FROM 11N-14N BETWEEN 85W-89W. 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 ID NO LONGER
PRODUCING CONVECTION OFF THE COAST OF FLORIDA. A 1021 MB HIGH IS
OVER THE W ATLANTIC NEAR 34N67W. A SURFACE TROUGH IS OVER THE
CENTRAL ATLANTIC ALONG 32N54W 27N60W 27N64W. A 1018 MB LOW HAS
DEVELOPED ON THE TROUGH AT 27N64W. SCATTERED SHOWERS ARE WITHIN
60 NM OF THE TROUGH...AND SCATTERED MODERATE CONVECTION IS FROM
27N-28N BETWEEN 62W-64W. A 1030 HIGH IS CENTERED NEAR THE AZORES
NEAR 41N30W. A RIDGE AXIS EXTENDS SW TO 28N50W. 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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