[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 020605
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU 02 SEP 2004

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...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0515 UTC.

...SPECIAL FEATURES...

CATEGORY FOUR HURRICANE FRANCES CENTER NEAR 22.7N 72.5W OR ABOUT
35 MILES...55 KM...NORTHEAST OF MAYAGUANA ISLAND IN THE BAHAMAS.
THIS IS ALSO ABOUT 555 MILES EAST-SOUTHEAST OF PALM BEACH
FLORIDA...AT 02/0300 UTC...MOVING WEST-NORTHWEST 12 KT. MAXIMUM
SUSTAINED WIND SPEED REMAINS AT 120 KT GUSTS 145 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE REPORTED BY A RECONNAISSANCE AIRCRAFT
IS 937 MB. SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT1/WTNT31 KNHC AND THE FORECAST/ ADVISORY UNDER
HEADERS MIATCMAT1/WTNT21 KNHC FOR ADDITIONAL INFORMATION.
FRANCES CONTINUES TO RADIATE IMPRESSIVE UPPER LEVEL CIRRUS OVER
THE NORTHERN...EASTERN...AND SOUTHERN QUADRANTS EXTENDING
OUTWARD UP TO 500 NM AWAY FROM THE CENTER. THE OUTFLOW IS
SLIGHTLY MORE RESTRICTED TO THE W OF THE HURRICANE...ABOUT
225 NM AWAY...AS IT RUNS INTO THE DRIER AIR NEAR AN UPPER TROF
BETWEEN THE BAHAMAS AND FLORIDA. THE INNER CORE OF FRANCES HAS
BEEN CYCLING THROUGH BURSTS OF CONVECTION AND POSSIBLY AN
EYEWALL REPLACEMENT CYCLE THROUGH THE AFTERNOON HOURS WITH THE
EYE SHRINKING TO ABOUT 8 NM WIDE AT 2045Z AND EXPANDING TO 16 NM
WIDE AS OF 2315Z. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM
20N TO 23.5N BETWEEN 70W AND 73W. VERY HEAVY RAINFALL AND STRONG
WINDS ARE NOW AFFECTING PARTS OF THE SOUTHEASTERN CARIBBEAN SEA
NOW...AND WILL CONTINUE TO SPREAD ACROSS THE REST OF THE
SOUTHERN BAHAMAS DURING THE COURSE OF TODAY.

THE COLDEST CLOUD TOPS...COLDER THAN ABOUT -70C...ARE ONCE AGAIN
WRAPPING ENTIRELY AROUND THE EYE AND IT SEEMS THAT THE
SHORT-TERM TREND IS FOR THE STORM TO MAINTAIN ITS CURRENT STATUS
OR EVEN GAIN A LITTLE STRENGTH. WATER TEMPERATURES ARE EXPECTED
TO BE WARMER NEAR THE BAHAMAS THAN THE TEMPERATURES OF THE OPEN
ATLANTIC WATERS...AND WITH THE FAVORABLE UPPER LEVEL
CONDITIONS...IT DOES NOT SEEM LIKELY THAT THIS HURRICANE WILL
LOSE MUCH STRENGTH AS IT HEADS TO THE NORTHWEST. RESIDENTS AND
VISITORS TO THE BAHAMAS AND FLORIDA ARE URGED TO FOLLOW THE
DIRECTIONS OF LOCAL EMERGENCY MANAGERS AND BE PREPARED TO
EXPERIENCE TROPICAL STORM OR HURRICANE CONDITIONS THROUGH THE
NEXT SEVERAL DAYS.

AN 1012 MB LOW PRESSURE CENTER IS NEAR 19N38W...ALONG A TROUGH/
THE NORTHERN PART OF A TROPICAL WAVE...WHICH IS ALONG 24N37W
19N38W 14N39W. SCATTERED MODERATE TO STRONG SHOWERS AND
THUNDERSTORMS FROM 18N TO 23N BETWEEN 35W AND 41W. STRONG
UPPER LEVEL SOUTHWESTERLY WINDS ARE AFFECTING THE SYSTEM
(CIMSS ESTIMATES SHOW 50 TO 60 KT OF SHEAR NORTHWEST OF THE
LOW CENTER). TROPICAL CYCLONE DEVELOPMENT IS POSSIBLE WITHIN THE
NEXT 36 HOURS IF THE LOW CENTER IS ABLE TO WITHSTAND THE SHEAR.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 17N21W 10N23W 7N23W...EAST OF THE CAPE VERDE
ISLANDS...MOVING WEST ABOUT 15 KT. AN 1010 MB LOW PRESSURE CENTER
IS ALONG THE WAVE NEAR 10N23W.  NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS FROM 10N TO 12.5N BETWEEN 24W AND 27W...AND FROM
7N TO 9N BETWEEN 25W AND 28W. SEVERAL NUMERICAL MODELS
STRENGTHEN THIS SYSTEM OVER THE ATLANTIC OCEAN WATERS.
IT WILL BE WATCHED FOR FURTHER DEVELOPMENT.

TROPICAL WAVE ALONG 24N55W 13N57W 7N57W...ABOUT 200 NM EAST OF
THE EASTERN CARIBBEAN SEA...MOVING WEST 15 KT. A MIDDLE TO UPPER
LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 25N48W. CYCLONIC FLOW
FROM 18N TO 32N BETWEEN 40W AND 55W. SCATTERED STRONG SHOWERS
AND THUNDERSTORMS FROM 19N TO 22N BETWEEN 46W AND 51W. ISOLATED
MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM 23N
TO 25N BETWEEN 51W AND 56W...AND FROM 23N TO 30N BETWEEN 48W AND
56W. BROAD MIDDLE LEVEL CYCLONIC TURNING IS PRESENT FROM 12N TO
20N BETWEEN 53W AND 61W. UPPER LEVEL ANTICYCLONIC OUTFLOW FROM
HURRICANE FRANCES REACHES THE EASTERN CARIBBEAN SEA ISLANDS NORTH
OF 15N. OTHER UPPER LEVEL...IN DRY AIR...APPEARS TO BE CUTTING
ACROSS THIS WAVE FROM WEST TO EAST...FROM BROAD UPPER LEVEL
CYCLONIC FLOW. ITCZ-RELATED SHOWERS AND THUNDERSTORMS ARE
WEAKENING FROM 10N TO 13N BETWEEN 53W AND 55W.

...ITCZ...

ITCZ 10N14W 8N23W 13N33W 9N50W 8N58W...AND IN THE CARIBBEAN SEA
10N76W 9N82W. ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND
THUNDERSTORMS IN THE WATERS WEST OF SIERRA LEONE AND GUINEA FROM
8N TO 9N BETWEEN 13W AND 14W...FROM 9N TO 12N BETWEEN 32W AND
40W...AND FROM 9N TO 12N BETWEEN 40W AND 60W. NO DISCERNIBLE
DEEP CONVECTIVE ACTIVITY IS APPARENT IN THE SOUTHWESTERN CORNER
OF THE CARIBBEAN SEA.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL RIDGE STRETCHES FROM THE MEXICO PACIFIC COAST
NEAR 22N105W TOWARD SOUTH TEXAS AND SOUTHEASTERN LOUISIANA. IT
HELPS TO HAVE EASTERN PACIFIC HURRICANE HOWARD NEAR 17.0N 112.4W
AND ITS ASSOCIATED UPPER LEVEL OUTFLOW. THE UPPER LEVEL MOISTURE
WITH THIS ANTICYCLONIC FLOW IS WEST OF 29N90W 24N92W 16N94W.
ISOLATED SHOWERS ARE WEST OF THIS LINE. ISOLATED MODERATE TO
LOCALLY STRONG SHOWERS AND THUNDERSTORMS SOUTH OF 28N EAST OF
THE 29N90W 16N94W LINE...IN AN AREA OF UPPER LEVEL DIFFLUENT
FLOW...WITH REGARD TO THE ATLANTIC-TO-STRAITS OF FLORIDA TROUGH
AND BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW ELSEWHERE IN THE
EASTERN AND NORTHEASTERN GULF. MIDDLE TO UPPER LEVEL CYCLONIC
FLOW FROM 15N TO 23N BETWEEN 85W AND 93W...ISOLATED MODERATE TO
LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM THE YUCATAN
PENINSULA TO THE ISTHMUS OF TEHUANTEPEC OF MEXICO.

...THE CARIBBEAN SEA...
MOST OF THE AREA ACTUALLY IS EXPERIENCING FAIRLY GOOD WEATHER...
WITH THE CIRCULATION OF HURRICANE FRANCES NOW NORTH OF
HISPANIOLA. THE DEEP-LAYERED FLOW IS MOSTLY FROM THE EAST BUT
EXTENSIVE CIRRUS OUTFLOW FROM THE HURRICANE HAS EXPANDED ACROSS
THE EXTREME WESTERN PART OF PUERTO RICO AND ALL OF HISPANIOLA...
EVEN APPEARING TO FAN OUT AS FAR SOUTH AS THE SOUTH CENTRAL
CARIBBEAN SEA WATERS...AND EVEN POSSIBLY TOUCHING NORTHERN
COLOMBIA. THERE IS A BIT OF A MIDDLE LEVEL TROUGH FROM THE
VENEZUELAN ISLANDS NORTHEASTWARD TO THE VIRGIN ISLANDS. MIDDLE
LEVEL DRY AIR IS IN PLACE WEST OF 65W...WITH THE UPPER LEVEL
HURRICANE OUTFLOW BLOWING RIGHT ON TOP OF IT.

...THE SUBTROPICAL ATLANTIC/THE TROPICAL ATLANTIC...
HURRICANE FRANCES IS MOVING TOWARD THE WEST-NORTHWEST AT THIS
MOMENT...ITS EYE IS NORTH OF THE SOUTHEASTERN BAHAMAS...MOVING
ROUGHLY TOWARD PARTS OF THE CENTRAL BAHAMAS. A MIDDLE TO UPPER
LEVEL TROUGH...AN OLD CLOSED CYCLONIC CENTER...RUNS FROM 31N74W
TO THE WATERS BETWEEN THE NORTHERN BAHAMAS AND FLORIDA...TOWARD
SOUTH FLORIDA AND THE STRAITS OF FLORIDA. THIS IS ADDING TO THE
WEAKNESS IN THE MIDDLE LEVEL RIDGE...WHICH IS ALLOWING HURRICANE
FRANCES TO TAKE A MORE WEST-NORTHWEST OR NORTHWEST TRACK NOW.
MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
25N48W. CYCLONIC FLOW FROM 18N TO 32N BETWEEN 40W AND 55W.
SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 19N TO 22N
BETWEEN 46W AND 51W. ISOLATED MODERATE TO LOCALLY STRONG SHOWERS
AND THUNDERSTORMS FROM 23N TO 25N BETWEEN 51W AND 56W...AND FROM
23N TO 30N BETWEEN 48W AND 56W. BROAD UPPER LEVEL ANTICYCLONIC
FLOW FROM THE EQUATOR TO 30N BETWEEN AFRICA AND 40W...EXCEPT
FOR A SMALL PART OF THE AREA ABOUT 350 NM WEST OF THE CANARY
ISLANDS...WHICH IS BEING OVERRUN BY THE BASE OF MIDDLE TO UPPER
LEVEL TROUGH WHICH IS DROPPING SOUTHWARD...AND COVERING THE AREA
NORTH OF 26N BETWEEN AFRICA AND 30W.

$$
MT

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