[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201155
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON AUG 20 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1015 UTC.

...SPECIAL FEATURE...
EXTREMELY DANGEROUS CATEGORY FOUR HURRICANE DEAN WAS NEAR 17.8N
81.5W...OR 380 NM/710 KM EAST OF BELIZE CITY AT 20/1200 UTC.
DEAN IS MOVING WEST 18 KT. THE MAXIMUM SUSTAINED WIND SPEEDS ARE
130 KT WITH GUSTS TO 160 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 926 MB. ALL RESIDENTS IN THE WESTERN CARIBBEAN
SEA...AND THE GULF OF MEXICO SHOULD MONITOR THE PROGRESS OF THIS
POWERFUL HURRICANE. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE LATEST
PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR THE MOST RECENT
WATCH AND WARNING INFORMATION. FOR STORM INFORMATION SPECIFIC TO
YOUR AREA...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS.
PLEASE MONITOR FORECASTS AND BULLETINS ISSUED BY YOUR LOCAL
WEATHER OFFICE.  NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE
FROM 16N TO 19N BETWEEN 80W AND 82W. STRONG SHOWERS AND
THUNDERSTORMS ARE IN BANDS ELSEWHERE AROUND THE CENTER FROM 15N
TO 20N BETWEEN 78W AND 83W. WIDELY SCATTERED MODERATE SHOWERS
AND ISOLATED STRONG THUNDERSTORMS ARE FROM 12N TO 18N BETWEEN
72W AND 75W.

...TROPICAL WAVES...

A LARGE ATLANTIC OCEAN TROPICAL WAVE IS ALONG 58W SOUTH OF 25N
MOVING WEST 20 KT DURING THE LAST 24 HOURS. THE 1010 MB LOW
PRESSURE CENTER FROM 6 HOURS AGO HAS DISSIPATED. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS FROM 23N TO 25N BETWEEN 55W AND 58W...
FROM 23N TO 25N BETWEEN 52W AND 55W...AND FROM 20N TO 21N BETWEEN
55W AND 57W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS FROM THE SOUTH AMERICA COAST OF GUYANA AND SURINAME
NORTHWARD TO 27N BETWEEN 50W AND 65W...AND IN PART OF THE ITCZ
STRETCHING NORTHWARD FROM 12N TO 22N BETWEEN 40W AND 50W.
THIS WAVE WILL CONTINUE TO BE MONITORED AS SLOW DEVELOPMENT
APPEARS POSSIBLE AS IT TRACKS WEST-NORTHWESTWARD DURING THE
NEXT COUPLE OF DAYS.

A GULF OF MEXICO TROPICAL WAVE IS ALONG 94W SOUTH OF 20N
MOVING WEST 10 TO 15 KT. A MIDDLE TO UPPER LEVEL CYCLONIC
CIRCULATION CENTER IS NEAR 26N93W. ALL THE PRECIPITATION
IN THE GULF OF MEXICO WEST OF 85W APPEARS TO BE RELATED
TO THIS CYCLONIC CENTER. NUMEROUS STRONG THUNDERSTORMS
IN THE GULF OF TEHUANTEPEC.

...THE ITCZ...
FROM THE AFRICA COAST NEAR 12N15W TO 9N33W TO 13N56W. STRONG
SHOWERS AND THUNDERSTORMS ARE FROM 6N TO 8N BETWEEN 42W AND
46W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS
ELSEWHERE FROM 2N TO 12N BETWEEN AFRICA NEAR 16W AND 40W...
AND ELSEWHERE FROM 5N TO 10N BETWEEN 40W AND 50W.

DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
26N93W CONTINUING TO MOVE WESTWARD ACROSS THE GULF OF MEXICO.
THE WESTWARD MOVEMENT OF 15 TO 20 KT THAT WAS PREDICTED BY MANY
OF THE COMPUTER MODELS HAS BEEN PRETTY ACCURATE...THUS LIMITING
ITS IMPACTS ON HURRICANE DEAN. CYCLONIC FLOW AROUND THE CENTER
COVERS THE AREA WEST OF 85W. ISOLATED MODERATE SHOWERS ARE IN
THE GULF WATERS NORTH OF 21N WEST OF 88W. WIDELY SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 27N
TO 28.5N BETWEEN 85W AND 86.5W IN MIDDLE LEVEL DIFFLUENT WIND
FLOW. THE DIFFLUENT FLOW IS COURTESY OF A MIDDLE LEVEL
ANTICYCLONIC CIRCULATION CENTER NEAR IN THE ATLANTIC OCEAN.
MIDDLE LEVEL ANTICYCLONIC FLOW IS IN THE GULF OF MEXICO EAST OF
85W...AND FROM THE BAHAMAS NORTHWARD WEST OF 70W IN THE ATLANTIC
OCEAN. A SURFACE RIDGE EXTENDS FROM SOUTHEASTERN GEORGIA TO
SOUTHEASTERN LOUISIANA TO THE DEEP SOUTH OF TEXAS. A TROPICAL
WAVE IS ALONG 94W SOUTH OF 20N.

THE CARIBBEAN SEA...
ALL THE ATTENTION REMAINS FOCUSED ON POWERFUL CATEGORY FOUR
HURRICANE DEAN. DEAN WILL CONTINUE TO HAVE SIGNIFICANT IMPACTS
ON THE CENTRAL AND WESTERN CARIBBEAN SEA AS WELL AS THE YUCATAN
PENINSULA FROM NOW UNTIL AND INCLUDING TUESDAY NIGHT. A MIDDLE
TO UPPER LEVEL TROUGH EXTENDS FROM THE ATLANTIC OCEAN NEAR
24N62W TO 14N64W IN THE NORTHEASTERN CORNER OF THE AREA. THE
LARGE CYCLONIC ENVELOPE COVERS THE ATLANTIC OCEAN AND THE
CARIBBEAN SEA FROM 16N TO 28N BETWEEN 50W AND 70W.

THE ATLANTIC OCEAN...
AN MIDDLE LEVEL ANTICYCLONIC CIRCULATION CENTER IS NEAR 30N75W.
MIDDLE LEVEL ANTICYCLONIC FLOW IS IN THE ATLANTIC OCEAN FROM THE
BAHAMAS NORTHWARD WEST OF 70W. THIS IS THE FEATURE STEERING DEAN
FAIRLY QUICKLY TO THE WEST OR WEST-NORTHWEST ACROSS THE WESTERN
CARIBBEAN SEA. DEAN'S STRONG CIRCULATION IS CAUSING DISTINCT
SINKING/DRYING BEYOND ITS OUTFLOW ACROSS THE CENTRAL BAHAMAS
AND REGIONS MORE TO THE NORTH. EASTERLY WINDS ARE QUITE
STRONG...25 TO 30 KT WITH HIGHER GUSTS ACROSS THE EXTREME
SOUTHWESTERN ATLANTIC OCEAN NEAR DEAN. A MIDDLE TO UPPER LEVEL
TROUGH EXTENDS FROM THE ATLANTIC OCEAN NEAR 24N62W TO 14N64W IN
THE NORTHEASTERN CORNER OF THE AREA. THE LARGE CYCLONIC ENVELOPE
COVERS THE ATLANTIC OCEAN AND THE CARIBBEAN SEA FROM 16N TO 28N
BETWEEN 50W AND 70W. THIS TROUGH IS RIGHT ON TOP OF THE 58W
TROPICAL WAVE. A MIDDLE LEVEL ANTICYCLONIC CIRCULATION CENTER IS
NEAR 14N40W. ANTICYCLONIC FLOW IS WITHIN A 360 NM RADIUS OF THE
CENTER. A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC
CIRCULATION CENTER NEAR 30N30W TO 22N36W. A SURFACE RIDGE PASSES
THROUGH 33N44W...TO JUST SOUTH OF BERMUDA...TO 31N80W.

$$
MT


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