[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 191154
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN AUG 19 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
1115 UTC.

...SPECIAL FEATURE...
AS OF 19/1200 UTC THE EYE OF EXTREMELY DANGEROUS HURRICANE DEAN
WAS LOCATED NEAR LATITUDE 16.8 NORTH...LONGITUDE 74.3 WEST OR
ABOUT 180 MILES...295 KM...EAST-SOUTHEAST OF KINGSTON JAMAICA.
DEAN IS MOVING TOWARD THE WEST NORTH-WEST NEAR 16 KT. MAXIMUM
SUSTAINED WINDS REMAIN NEAR 125 KT WITH HIGHER GUSTS...THIS
MAKES DEAN A STRONG CATEGORY FOUR HURRICANE. THE ESTIMATED
MINIMUM CENTRAL PRESSURE WAS 921 MB. SOME FLUCTUATIONS IN
INTENSITY ARE LIKELY DURING THE NEXT 24 HOURS. ALL INTERESTS IN
THE CENTRAL AND WESTERN CARIBBEAN SEA...AND THE GULF OF MEXICO
SHOULD CLOSELY 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 PRODUCTS ISSUED BY YOUR LOCAL WEATHER OFFICE. DEAN
REMAINS VERY IMPRESSIVE ON SATELLITE IMAGERY WITH A WELL-DEFINED
EYE AND SYMMETRIC SIGNATURE TO IT'S EYEWALL ...RAINBANDS AND
OUTFLOW. EYE DIAMETER IS 15 NM. NUMEROUS MODERATE TO STRONG IS
WITHIN 75 NM OF THE CENTER. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION...IN SPIRAL BANDS...IS ELSEWHERE FROM 13N-19N
BETWEEN 70W-76W.

...TROPICAL WAVES...
A VERY LARGE TROPICAL WAVE IS ALONG 46W S OF 21N MOVING W 15 KT.
A DISTINCT LOW LEVEL CIRCULATION IS NOTED NEAR 13N46W. A VERY
BROAD ELONGATED AREA OF LOW TO MID LEVEL CYCLONIC TURNING NOW
EXTENDS BETWEEN 30W AND 60W.  ISOLATED MODERATE CONVECTION IS E
OF THE WAVE AXIS FROM 7N-12N BETWEEN 36W-44W.  PATCHES OF WIDELY
SCATTERED MODERATE CONVECTION IS OVER THE NRN PART OF THE WAVE
FROM 17N-20N BETWEEN 39W-52W.  ISOLATED MODERATE CONVECTION IS W
OF THE WAVE AXIS FROM 10N-12N BETWEEN 52W-56W.

TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 90W S OF 21N
MOVING W 15-20 KT. A WEAK INVERTED V-SHAPE IS SEEN ON SATELLITE
IMAGERY. THE NORTHERN PART OF THE WAVE IS BEING MASKED HOWEVER
BY AN UPPER LEVEL LOW CENTERED OVER THE ERN GULF OF MEXICO.
SCATTERED SHOWERS ARE FROM 13N-17N BETWEEN 87W -92W.  SCATTERED
MODERATE CONVECTION IS FURTHER S IN THE ERN PACIFIC FROM 11N-13N
BETWEEN 89W-92W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 8N20W 11N30W 13N40W 11N50W
7N60W. BESIDES THE ACTIVITY MENTIONED ABOVE...SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION IS S OF THE ITCZ AXIS FROM 4N-7N
BETWEEN 25W-28W.

DISCUSSION...

THE GULF OF MEXICO...
WEAK SURFACE RIDGING IS OVER THE GULF OF MEXICO WITH RIDGE AXIS
ALONG 30N. THUS SURFACE WINDS ARE MOSTLY FROM THE E AT 10-15 KT
E OF 80W...AND FROM THE SE AT 10-15 KT W OF 80W.  PATCHES OF
SHOWERS AND ISOLATED THUNDERSTORMS ARE STREAMING OVER CENTRAL
AND SOUTH FLORIDA WITH THE EASTERLIES. IN THE UPPER LEVELS...AN
UPPER LEVEL LOW IS CENTERED OVER THE ERN GULF NEAR 25N87W MOVING
W.  CYCLONIC FLOW IS BETWEEN 80W-94W.  THE SYSTEM IS PRODUCING
NOCTURNAL THUNDERSTORMS FROM 22N-26N BETWEEN 85W-90W.  UPPER
LEVEL RIDGING IS OVER THE WRN GULF PRODUCING NLY FLOW W OF 94W.
ALL EYES ARE ON HURRICANE DEAN WHICH IS EXPECTED TO MOVE INTO
THE SW PORTION OF THE GULF ON TUE NIGHT.

THE CARIBBEAN SEA...
ATTENTION REMAINS FOCUSED ON POWERFUL CATEGORY FOUR HURRICANE
DEAN. DEAN WILL CONTINUE TO HAVE SIGNIFICANT IMPACTS ON THE
CENTRAL AND WESTERN CARIBBEAN AS WELL AS THE YUCATAN PENINSULA
THROUGH TUE NIGHT. FOR DETAILS REFER TO THE SPECIAL FEATURE
SECTION ABOVE. A TROPICAL WAVE IS ALSO TRAVERSING CENTRAL
AMERICA WITH LIMITED CONVECTION.  ELSEWHERE...ISOLATED MODERATE
CONVECTION IS ALONG THE COAST OF NRN VENEZUELA...NRN
COLOMBIA...PANAMA...AND COSTA RICA S OF 12N. IN THE UPPER
LEVELS...A TROUGH IS OVER THE NW CARIBBEAN SEA N OF 18N AND W OF
80W. UPPER LEVEL OUTFLOW FROM DEAN IS NOW NOTED E OF 80W.

THE ATLANTIC OCEAN...
A LARGE SCALE RIDGE DOMINATES THE ATLANTIC OCEAN...ANCHORED BY A
1032 MB HIGH W OF THE AZORES AT 38N34W PRODUCING WIDESPREAD FAIR
WEATHER AND MODERATE TRADES E OF 60W.  IN THE UPPER LEVELS...
A RIDGE IS OVER THE W ATLANTIC N OF 25N AND W OF 70W THAT IS
PUSHING S AND WILL EFFECT THE FUTURE TRACK OF DEAN. AN UPPER LOW
IS OVER THE CENTRAL ATLANTIC NEAR 30N56W MOVING W.  LIGHTNING
DATA HAS BEEN DEPICTING A FEW ISOLATED TSTMS ASSOCIATED WITH
THIS FEATURE FROM 27N-34N BETWEEN 50W-57W. UPPER RIDGING IS OVER
THE ERN ATLANTIC E OF 40W.

$$
FORMOSA





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