[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 111158 AAA
TWDAT

TROPICAL WEATHER DISCUSSION...UPDATED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 11 2005

...UPDATED FOR 1200 UTC INFORMATION ON OPHELIA...

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURE...

HURRICANE OPHELIA CENTERED NEAR 31.6N 75.7W...OR 220 NM ESE OF
CHARLESTON SOUTH CAROLINA...AT 11/1200 UTC WITH NEARLY
STATIONARY MOVEMENT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 979
MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC AND THE PUBLIC ADVISORY UNDER HEADERS
MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. OPHELIA FINDS ITSELF IN
THE MIDDLE OF TWO AREAS OF DEEP AND BROAD ANTICYCLONIC FLOW. ONE
AREA OF ANTICYCLONIC FLOW IS IN THE EASTERN U.S.A. AND THE OTHER
ONE IS IN THE ATLANTIC OCEAN NORTH OF 10N BETWEEN 40W AND 70W.
OPHELIA IS NOT FORECAST TO HAVE MUCH MOVEMENT TO IT FOR THE NEXT
3 DAYS OR SO. SCATTERED MODERATE TO STRONG SHOWERS AND
THUNDERSTORMS FROM 31N TO 33N BETWEEN 74W AND 77W. ISOLATED TO
WIDELY SCATTERED MODERATE SHOWERS AND LOCALLY STRONG
THUNDERSTORMS ELSEWHERE FROM 30N TO 34N BETWEEN 65W AND 74W.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE IS ALONG 37W SOUTH OF 23N MOVING
WEST 10 TO 15 KT. THE WAVE REMAINS IN A DRY AND STABLE
ENVIRONMENT WITH NO ASSOCIATED CONVECTION.

CARIBBEAN SEA TROPICAL WAVE IS ALONG 63W/64W SOUTH OF 21N IS
MOVING WEST 15 KT. THE STRONG SHOWERS AND THUNDERSTORMS IN THE
SOUTHEASTERN CORNER OF THE CARIBBEAN SEA FROM 6 HOURS AGO HAVE
GIVEN WAY TO ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND
THUNDERSTORMS FROM 10N TO 15N BETWEEN 60W AND 64W. SCATTERED
MODERATE TO ISOLATED STRONG SHOWERS FROM 19N TO 23N BETWEEN
54W AND 70W...IN AN AREA OF SOME UPPER LEVEL DIFFLUENT FLOW.
THIS PRECIPITATION IS OCCURRING AT THE PERIPHERY OF LARGE
SCALE ANTICYCLONIC FLOW IN THE ATLANTIC OCEAN...TO THE
SOUTHEAST OF THE FLOW AROUND HURRICANE OPHELIA...AND EAST
AND NORTHEAST OF AN AREA OF WEAK MIDDLE TO UPPER LEVEL
CYCLONIC FLOW/TROUGH NEAR THE MONA PASSAGE.

CARIBBEAN SEA TROPICAL WAVE IS ALONG 76W SOUTH OF 20N IS
MOVING WEST 15 KT. THIS WAVE IS IN AN AREA OF MIDDLE TO UPPER
LEVEL DIFFLUENT FLOW. IT IS NOT EASY TO FIND ANY SHOWER OR
THUNDERSTORM ACTIVITY TO THE THIS WAVE.

WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 91W/92 SOUTH OF 22N
MOVING WEST 15 KT. THIS WAVE IS CONTINUING TO INTERACT WITH THE
MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER WHICH SPANS
THE YUCATAN PENINSULA. STRONG SHOWERS AND THUNDERSTORMS ARE
OCCURRING OFF THE EASTERN SHORES OF NICARAGUA AND HONDURAS.
STRONG SHOWERS AND THUNDERSTORMS WERE SOUTH OF CUBA...NORTHWEST
OF JAMAICA 5 TO 6 HOURS AGO...BUT SINCE THAT TIME THE CLOUD TOP
TEMPERATURES HAVE BECOME COMPARATIVELY WARMER...WEAKENING SOME
OF THE CONVECTIVE ACTIVITY.

...ITCZ...

ITCZ 13N17W 12N23W 10N34W 9N39W 9N50W 10N61W. ISOLATED TO WIDELY
SCATTERED MODERATE SHOWERS AND LOCALLY STRONG THUNDERSTORMS ARE
FOUND FROM 3N TO 11N BETWEEN 10W AND 50W...AND ISOLATED MODERATE
SHOWERS FROM 4N TO 13N BETWEEN 50W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...
A SURFACE RIDGE RUNS FROM NORTHERN ALABAMA TO THE CENTRAL TEXAS
COAST. A TROPICAL WAVE ALONG 91W/92W IS MOVING THROUGH THE AREA
OF AN ALREADY-EXISTING MIDDLE TO UPPER LEVEL YUCATAN PENINSULA
LOW PRESSURE CENTER. ISOLATED SHOWERS ARE JUST OFFSHORE THE
NORTHWESTERN CORNER OF THE YUCATAN PENINSULA. ANOTHER MIDDLE
TO UPPER LEVEL LOW PRESSURE CENTER IS IN INTERIOR NORTH CENTRAL
MEXICO. SHOWERS AND THUNDERSTORMS ARE IN THE GULF WATERS AND
COASTAL PLAINS OF THE MIDDLE TEXAS GULF COAST. MIDDLE TO UPPER
LEVEL DRY AIR IS IN THE GULF WATERS NORTH OF 23N EAST OF 93W.
NOT TOO MANY CLOUDS ARE IN THIS AREA.

THE CARIBBEAN SEA...
A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 91W/92 SOUTH OF
22N MOVING WEST 15 KT. THIS WAVE IS CONTINUING TO INTERACT WITH
THE MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER WHICH SPANS
THE YUCATAN PENINSULA. STRONG SHOWERS AND THUNDERSTORMS ARE
OCCURRING OFF THE EASTERN SHORES OF NICARAGUA AND HONDURAS.
STRONG SHOWERS AND THUNDERSTORMS WERE SOUTH OF CUBA...NORTHWEST
OF JAMAICA 5 TO 6 HOURS AGO...BUT SINCE THAT TIME THE CLOUD TOP
TEMPERATURES HAVE BECOME COMPARATIVELY WARMER...WEAKENING SOME
OF THE CONVECTIVE ACTIVITY. ANOTHER TROPICAL WAVE IS ALONG 76W
SOUTH OF 20N. AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG
63W/64W SOUTH OF 21N IS MOVING WEST 15 KT. THE STRONG SHOWERS
AND THUNDERSTORMS IN THE SOUTHEASTERN CORNER OF THE CARIBBEAN
SEA FROM 6 HOURS AGO HAVE GIVEN WAY TO ISOLATED MODERATE TO
LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM 10N TO 15N BETWEEN
60W AND 64W. SCATTERED MODERATE TO ISOLATED STRONG SHOWERS FROM
19N TO 23N BETWEEN 54W AND 70W...IN AN AREA OF SOME UPPER LEVEL
DIFFLUENT FLOW. THIS PRECIPITATION IS OCCURRING AT THE PERIPHERY
OF LARGE SCALE ANTICYCLONIC FLOW IN THE ATLANTIC OCEAN...TO THE
SOUTHEAST OF THE FLOW AROUND HURRICANE OPHELIA...AND EAST AND
NORTHEAST OF AN AREA OF WEAK MIDDLE TO UPPER LEVEL CYCLONIC
FLOW/TROUGH NEAR THE MONA PASSAGE.

THE ATLANTIC OCEAN...
HURRICANE OPHELIA IS IN THE WESTERN ATLANTIC OCEAN.
A 1020 MB HIGH IS NEAR 26N63W. A 1025 MB HIGH IS OVER THE
EASTERN ATLANTIC OCEAN NEAR 36N17W. ANTICYCLONIC FLOW IS NORTH
OF 25N AND EAST OF 30W. A SMALL UPPER LEVEL HIGH APPEARS TO BE
CENTERED JUST SW OF OPHELIA AND IS PRODUCING A FAIRLY FAVORABLE
OUTFLOW PATTERN OVER THE CYCLONE. AN UPPER LEVEL LOW IS CENTERED
NORTH OF THE SE BAHAMAS NEAR 24N73W.  THE UPPER LOW IS PRODUCING
SCATTERED MODERATE CONVECTION NE OF CENTER FROM 25N TO 28N
BETWEEN 69W AND 71W. THIS UPPER LOW IS FORECAST TO WEAKEN AS IT
CONTINUES TO MOVE NE. A VERY LARGE AND STRONG UPPER LEVEL HIGH
IS CENTERED OVER THE CENTRAL ATLC WATERS NEAR 25N51W WITH A
RIDGE AXIS EXTENDING WNW  TOWARDS OPHELIA. THE HIGH IS PRODUCING
BROAD ANTICYCLONIC FLOW OVER MOST OF THE ENTIRE AREA BETWEEN
35W-65W. THE ONLY EXCEPTION IS NEAR A WEAK MID/UPPER LEVEL LOW
IS LOCATED SE OF THE HIGH NEAR 14N44W...AND IS MOVING WSW AT
15-20 KT. A STATIONARY UPPER LEVEL TROUGH EXTENDS FROM NEAR THE
CANARY ISLANDS SW ALONG 20N27W TO NEAR THE UPPER LOW MENTIONED
ABOVE.

$$
MT/BERG





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