[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 190606
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT AUG 18 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURE...
AS OF 19/0600 UTC THE EYE OF EXTREMELY DANGEROUS HURRICANE DEAN
WAS LOCATED NEAR NEAR LATITUDE 16.4 NORTH...LONGITUDE 72.6 WEST
OR ABOUT 295 MILES...480 KM...EAST-SOUTHEAST OF KINGSTON JAMAICA
AND ABOUT 155 MILES...245 KM...SOUTH OF PORT AU PRINCE HAITI.
DEAN IS MOVING TOWARD THE WEST NORTH-WEST NEAR 15 KT. MAXIMUM
SUSTAINED WINDS REMAIN NEAR 125 KT WITH GUSTS TO 155 KT...THIS
MAKES DEAN A STRONG CATEGORY FOUR HURRICANE. THE MINIMUM CENTRAL
PRESSURE REPORTED BY AN AIR FORCE RESERVE RECONNAISSANCE
AIRCRAFT WAS 918 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. 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 69W-74W.

...TROPICAL WAVES...
A VERY LARGE TROPICAL WAVE IS REPOSITIONED ALONG 45W S OF 21N
MOVING W 20 KT.   A DISTINCT LOW LEVEL CIRCULATION IS NOTED NEAR
12N45W THAT WAS BETWEEN TWO FORMERLY TRACKED TROPICAL WAVES.
BOTH WAVES WERE DROPPED AND A NEW MEDIAN WAVE WAS CREATED.  A
VERY BROAD ELONGATED AREA OF LOW TO MID LEVEL CYCLONIC TURNING
NOW EXTENDS BETWEEN 30W AND 60W.  WIDELY SCATTERED MODERATE
CONVECTION IS E OF THE WAVE AXIS FROM 7N-12N BETWEEN 36W-43W.
PATCHES OF SCATTERED MODERATE CONVECTION IS OVER THE NRN PART OF
THE WAVE FROM 16N-20N BETWEEN 43W-50W.  ISOLATED MODERATE
CONVECTION IS W OF THE WAVE AXIS FROM 10N-12N BETWEEN 51W-54W.

TROPICAL WAVE IS OVER CENTRAL AMERICA AND THE W CARIB ALONG 88W
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 MODERATE CONVECTION IS ALONG THE COAST OF
HONDURAS FROM 15N-17N BETWEEN 87W-89W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N15W 10N20W 11N30W 13N40W 10N50W
7N60W. BESIDES FOR THE ACTIVITY MENTIONED ABOVE...SCATTERED
MODERATE CONVECTION IS S OF THE ITCZ AXIS FROM 5N-7N BETWEEN
23W-27W.

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 SE AT 10-15
KT. A PATCH OF SCATTERED MODERATE CONVECTION IS OVER THE FLORIDA
PANHANDLE NEAR FROM 30N-31N BETWEEN 85W-86W.  SIMILAR CONVECTION
IS OVER THE BAY OF CAMPECHE FROM 18N-20N BETWEEN 91W-93W. THE
REMAINDER OF THE GULF OF MEXICO IS VOID OF CONVECTION. IN THE
UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER THE ERN GULF
NEAR 25N86W MOVING W.  CYCLONIC FLOW IS BETWEEN 80W-94W.  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 W/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...SCATTERED MODERATE
CONVECTION IS ALONG THE COAST OF NRN VENEZUELA FROM 11N-13N
BETWEEN 68W-70W. 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
1034 MB HIGH W OF THE AZORES AT 40N35W 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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