[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091113
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUL 09 2005

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 1015 UTC.

...SPECIAL FEATURE...
AT 7 AM EDT...1100Z...THE EYE OF HURRICANE DENNIS WAS LOCATED
NEAR 24.1N 83.2W...OR ABOUT 95 MILES WEST-SOUTHWEST OF KEY WEST
FLORIDA. DENNIS IS MOVING TOWARD THE NORTHWEST NEAR 14 MPH AND
THIS MOTION IS EXPECTED TO CONTINUE DURING THE NEXT 24 HOURS.
A NOAA RECONNAISSANCE PLANE INDICATES THAT WINDS ARE BEGINNING
TO INCREASE AGAIN AND HAVE REACHED 105 MPH...WITH HIGHER GUSTS.
DENNIS IS NOW A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON
SCALE.  SOME RE-STRENGTHENING IS FORECAST DURING THE NEXT
24 HOURS. HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 65 MILES
FROM THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD
UP TO 175 MILES. KEY WEST HAS EXPERIENCED A GUST TO 74 MPH...
HURRICANE FORCE. SOMBRERO KEY...AN ELEVATED PLATFORM NEAR
MARATHON FLORIDA...REPORTED SUSTAINED HURRICANE FORCE WINDS
OF 74 MPH WITH A GUST TO 88 MPH. MINIMUM CENTRAL PRESSURE
REPORTED BY AN AIR FORCE RECONNAISSANCE AIRCRAFT WAS 969 MB...
28.61 INCHES. PLEASE SEE THE LATEST NHC PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND THE FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE
DETAILS. DENNIS WEAKENED AS IT PASSED OVER CUBA...AND NOW HAS
RE-ENTERED THE WATERS...NOW IN THE SOUTHEASTERN GULF OF MEXICO.
THE PRESSURE HAS FILLED A BIT MORE...NOW UP TO 972 MB. THE UPPER
LEVEL RIDGE AROUND WHICH DENNIS IS MOVING STILL RUNS FROM THE
ATLANTIC OCEAN NEAR 32N70W...ACROSS FLORIDA INTO THE EAST
CENTRAL GULF OF MEXICO. THE MIDDLE TO UPPER LEVEL TROUGH FROM
24 HOURS AGO...MOVING THROUGH TEXAS EASTWARD... REMAINS AND NOW
EXTENDS FROM THE MIDDLE MISSISSIPPI VALLEY SOUTHWESTWARD TO THE
TEXAS COAST. ALL THE CLOUDS AND UGLY WEATHER ARE EAST OF
87W/88W... WITH MIDDLE TO UPPER LEVEL DRY AIR WEST OF THIS
BOUNDARY. A SURFACE STATIONARY FRONT...WITH THE MIDDLE TO UPPER
LEVEL TROUGH...LINGERS FROM EASTERN GEORGIA TO NORTH CENTRAL
LOUISIANA . ISOLATED SHOWERS ARE ALONG THE NORTHWESTERN GULF
COAST FROM SOUTHWESTERN LOUISIANA TO THE MIDDLE TEXAS COAST. ONE
AREA OF SOLID STRONG SHOWERS AND THUNDERSTORMS FROM 20N TO 22N
BETWEEN 79W AND 82W NEAR AND SOUTH OF CUBA...FROM 23N TO 25N
BETWEEN 82W AND 85W IN THE SOUTHEASTERN GULF OF MEXICO...AND
ACROSS FLORIDA WITHIN 30 NM ON EITHER SIDE OF 25N79W 27N80W
27N83W. OVERCAST MULTILAYERED CLOUDS AND OTHER POSSIBLE
SHOWERS/THUNDERSTORMS ALSO ARE WEST OF 32N76W 24N70W COVERING
THE BAHAMAS ISLANDS IN THE WESTERN ATLANTIC OCEAN. CLOUD COVER
IN GENERAL AROUND HURRICANE DENNIS IN THE CARIBBEAN SEA IS
EXTENSIVE NORTH OF 13N WEST OF 68W.

...TROPICAL WAVES...

THE WAVE REPORTED EARLIER TO BE ALONG 29W/30W HAS BEEN CHANGED
TO BE TREATED AS A TROUGH...NOT A TROPICAL WAVE. IT IS MOVING
WEST 10 KT. ITCZ PRECIPITATION IS IN THE VICINITY OF THIS WAVE.

THE SURFACE LOW NEAR 11N36W FROM THE 09/0000 UTC ANALYSIS HAS
BEEN ATTACHED TO A TROPICAL WAVE WHICH WAS PLACED ALONG 36W...
BASED ON LONG-TERM SATELLITE IMAGERY. IT IS MOVING WEST 10 TO
15 KT. SHOWERS AND THUNDERSTORMS IN INDIVIDUAL CLUSTERS COVER
THE WATERS FROM 5N TO 12N BETWEEN 30W AND 40W. SOME OF THIS
PRECIPITATION PROBABLY IS MORE RELATED TO THE ITCZ THAN TO THIS
LOW CENTER.

IT WAS DETERMINED...VIA LONG-TERM SATELLITE IMAGERY...THAT THE
FEATURE REPORTED EARLIER TO BE A TROPICAL WAVE ACTUALLY IS A
TROUGH FROM AN EARLIER BAROCLINIC SYSTEM. THIS TROUGH IS ALONG
43W/44W FROM 9N TO 18N. NO PRECIPITATION IS DIRECTLY RELATED TO
THIS WAVE.

TROPICAL WAVE ALONG 60W/61W HAS ENTERED THE EASTERN CARIBBEAN
SEA. UPPER LEVEL SOUTHERLY WIND FLOW CONTINUES TO CUT ACROSS THE
AREA THROUGH WHICH THIS WAVE IS MOVING. ISOLATED MODERATE
SHOWERS AND POSSIBLE THUNDERSTORMS ARE FOUND FROM 10N TO 16N
BETWEEN 58W AND 66W.

...THE ITCZ...

ITCZ 11N16W 11N21W 12N27W...12N31W 11N35W...10N39W 7N42W...7N45W
8N58W. STRONG SHOWERS AND THUNDERSTORMS FROM 10N TO 12N BETWEEN
AFRICA AND 19W. ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND
THUNDERSTORMS FROM FRENCH GUIANA TO 8N BETWEEN 51W AND 55W.

...DISCUSSION...

GULF OF MEXICO...
HURRICANE DENNIS DOMINATES THE WEATHER STORY FOR THE EASTERN
GULF OF MEXICO...THE YUCATAN CHANNEL AREA AND OTHER PARTS OF
THE NORTHWESTERN CARIBBEAN SEA...AND THE ATLANTIC OCEAN WATERS
ADJACENT TO FLORIDA AND OVER THE BAHAMAS. THE MIDDLE TO UPPER
LEVEL TROUGH FROM 24 HOURS AGO...MOVING THROUGH TEXAS
EASTWARD...REMAINS AND NOW EXTENDS FROM THE MIDDLE MISSISSIPPI
VALLEY SOUTHWESTWARD TO THE TEXAS COAST. ALL THE CLOUDS AND UGLY
WEATHER ARE EAST OF 87W/88W...WITH MIDDLE TO UPPER LEVEL DRY AIR
WEST OF THIS BOUNDARY. A SURFACE STATIONARY FRONT...WITH THE
MIDDLE TO UPPER LEVEL TROUGH...LINGERS FROM EASTERN GEORGIA TO
NORTH CENTRAL LOUISIANA. ISOLATED SHOWERS ARE ALONG THE
NORTHWESTERN GULF COAST FROM SOUTHWESTERN LOUISIANA TO THE
MIDDLE TEXAS COAST. ONE AREA OF SOLID STRONG SHOWERS AND
THUNDERSTORMS FROM 20N TO 22N BETWEEN 79W AND 82W NEAR AND
SOUTH OF CUBA...FROM 23N TO 25N BETWEEN 82W AND 85W IN THE
SOUTHEASTERN GULF OF MEXICO...AND ACROSS FLORIDA WITHIN
30 NM ON EITHER SIDE OF 25N79W 27N80W 27N83W.

THE CARIBBEAN SEA...
HURRICANE DENNIS DOMINATES THE WEATHER STORY IN THE AREA OF THE
YUCATAN CHANNEL AND SURROUNDING PARTS OF THE NORTHWESTERN CORNER
OF THE AREA. A MIDDLE TO UPPER LEVEL TROUGH ORIGINATES IN THE
ATLANTIC OCEAN NEAR 25N56W AND EXTENDS TO 22N60W...ENTERING
THROUGH THE NORTHEASTERN CORNER TO 13N67W...BRINGING WITH IT
MIDDLE TO UPPER LEVEL DRY AIR WITHIN 100 NM ON EITHER SIDE OF
IT. THE 60W/61W TROPICAL WAVE BRINGS SOME SHOWERS AND POSSIBLE
THUNDERSTORMS...FOR THE MOMENT...TO THE EASTERN CARIBBEAN SEA
ISLANDS FROM 10N TO 16N BETWEEN 58W AND 66W.

THE ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE RUNS FROM 32N704W...ACROSS FLORIDA...INTO
THE EAST-CENTRAL GULF OF MEXICO. CLOUDINESS AND SHOWERS AROUND
HURRICANE DENNIS ARE WEST OF THE LINE FROM 32N76W TO 24N70W
COVERING THE BAHAMAS ISLANDS IN THE WESTERN ATLANTIC OCEAN.
A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
25N70W...ISOLATED MODERATE SHOWERS ARE IN BETWEEN THIS 25N70W
CYCLONIC CENTER AND THE ATLANTIC-TO-CARIBBEAN SEA TROUGH.
A SURFACE TROUGH RUNS FROM 29N60W TO 24N66W TO 22N73W.
MIDDLE LEVEL CYCLONIC WIND FLOW FROM A NOT WELL PRONOUNCED
MIDDLE TO UPPER LEVEL TROUGH COVERS THE WATERS ROUGHLY FROM 10N
TO 20N BETWEEN 35W AND 50W. BROAD SURFACE ANTICYCLONIC WIND FLOW
COVERS THE ATLANTIC WATERS NORTH OF 20N BETWEEN AFRICA AND THE
30N58W 25N62W SURFACE TROUGH. A SURFACE RIDGE EXTENDS FROM A
1023 MB HIGH PRESSURE CENTER NEAR 31N64W TO 30N80W.

$$
MT


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