[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181058
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE AUG 18 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...SPECIAL FEATURES...
THE CENTER OF HURRICANE BILL AT 18/0900 UTC IS NEAR 15.5N
49.7W...OR ABOUT 810 MILES...1305 KM...EAST OF THE LEEWARD
ISLANDS MOVING WNW AT 15 KT. THE ESTIMATED CENTRAL PRESSURE IS
967 MB. MAXIMUM SUSTAINED WIND SPEEDS REMAIN AT 85 KT WITH GUSTS
UP TO 105 KT. HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 25
MILES...FROM THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND
OUTWARD UP TO 130 MILES. GRADUAL INTENSIFICATION IS EXPECTED.
PLEASE READ THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
TCMAT3/ WTNT23 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO
STRONG CONVECTION IS CURRENTLY FROM 13N-17N BETWEEN 47W-52W.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 33W S OF 17N MOVING W NEAR 20 KT. THE
WAVE LIES ON A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL
PRECIPITABLE WATER IMAGERY WITH A DRY SLOT W OF THE WAVE AXIS AT
12N. WIDELY SCATTERED MODERATE CONVECTION IS FROM 14N-16N
BETWEEN 30W-34W... AND FROM 7N-8N BETWEEN 31W-33W.

A TROPICAL WAVE...THE REMNANTS OF ANA...IS ALONG 73W S OF 20N
MOVING W NEAR 20-25 KT. LOCALLY HEAVY RAINFALL AND GUSTY WINDS
THREATEN HISPANIOLA AND CUBA OVER THE NEXT COUPLE OF DAYS.
PRESENTLY SCATTERED MODERATE CONVECTION IS N OF HISPANIOLA FROM
21N-24N BETWEEN 72W-75W. SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS S OF HISPANIOLA FROM 17N-19N BETWEEN 71W-75W.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 11N15W 10N25W 11N33W 10N37W
14N45W 13N51W 9N61W. SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS ALONG THE COAST OF W AFRICA FROM 6N-10N BETWEEN
13W-20W...AND FROM 10N-12N BETWEEN 18W-20W. SCATTERED SHOWERS
ARE FROM 6N-11N BETWEEN 25W-50W.

...DISCUSSION...

THE GULF OF MEXICO...
WEAK HIGH PRESSURE RIDGING IS OVER THE GULF OF MEXICO WITH AXIS
ALONG 30N. A GOOD AMOUNT OF TROPICAL MOISTURE STILL REMAINS
HOWEVER OVER THE GULF N OF 25N. FURTHER S...SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION IS OVER THE BAY OF CAMPECHE FROM
17N-21N BETWEEN 93W-96W. SURFACE WINDS ARE PREDOMINATELY FROM
THE SE AT 10-15 KT. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS
CENTERED OVER THE NE GULF NEAR 28N88W. A SMALL UPPER LEVEL LOW
IS CENTERED OVER MEXICO NEAR 21N101W. A GOOD AMOUNT OF UPPER
LEVEL MOISTURE BLANKETS THE ENTIRE GULF. EXPECT...A SURFACE
TROUGH OVER THE BAHAMAS TO MOVE OVER FLORIDA AND THE SE GULF
OVER THE NEXT 24 HOURS WITH CONVECTION. ALSO EXPECT MORE
CONVECTION OVER THE N GULF N OF 25N.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS ALONG 73W. SEE ABOVE. ELSEWHERE...SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS OVER BELIZE AND
GUATEMALA FROM 15N-17N BETWEEN 88W-91W. CLUSTERS OF WIDELY
SCATTERED MODERATE CONVECTION ARE OVER W VENEZUELA...N
COLOMBIA...AND PANAMA FROM 5N-11N BETWEEN 70W-83W. IN THE UPPER
LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER CENTRAL CUBA NEAR
22N79W. ZONAL FLOW IS OVER THE E CARIBBEAN E OF 70W. EXPECT...
CONVECTION TO MOVE OVER CUBA...THE NW CARIBBEAN...AND CENTRAL
AMERICA OVER THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
A SURFACE TROUGH IS OVER THE N BAHAMAS AND THE W ATLANTIC ALONG
31N74W 27N81W 23N81W. SCATTERED SHOWERS ARE WITHIN 30 NM OF THE
TROUGH. ANOTHER SURFACE TROUGH IS N OF HISPANIOLA ALONG 27N67W
25N71W 22N73W. WIDELY SCATTERED MODERATE CONVECTION IS 150 NM N
OF THE TROUGH. A 1023 MB HIGH IS OVER THE W ATLANTIC OFF THE
COAST OF NORTH CAROLINA NEAR 35N74W. ANOTHER 1022 MB HIGH IS
OVER THE E ATLANTIC NEAR 32N32W. IN THE UPPER LEVELS...THE UPPER
LEVEL LOW CENTERED OVER CUBA IS PRODUCING DIFFLUENCE OVER THE S
BAHAMAS...ENHANCING SHOWERS FROM 20N-28N BETWEEN 70W-75W. AN
UPPER LEVEL HIGH IS CENTERED NEAR 20N60W. AN UPPER LEVEL TROUGH
IS OVER THE CENTRAL ATLANTIC N OF 20N BETWEEN 50W-60W. AN UPPER
LEVEL HIGH IS OVER THE E ATLANTIC NEAR 30N35W. AN UPPER LEVEL
TROUGH IS OVER THE CANARY ISLANDS. EXPECT BILL TO BE THE
DOMINATE FEATURE OVER THE TROPICAL CENTRAL ATLANTIC FOR THE NEXT
SEVERAL DAYS WHILE THE REMNANTS OF ANA MOVES TOWARDS FLORIDA.

$$
FORMOSA







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