[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190554
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED AUG 19 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0415 UTC.

...SPECIAL FEATURES...
HURRICANE BILL IS CENTERED NEAR NEAR 17.2N 53.4W OR ABOUT 480 NM
EAST OF THE LEEWARD ISLANDS MOVING WNW AT 13 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 952 MB. MAXIMUM SUSTAINED WIND SPEED
IS 110 KT WITH GUSTS TO 135 KT. SEE THE LATEST FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS TCMAT3/WTNT23 KNHC FOR MORE DETAILS.
SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 120 NM OF THE
CENTER IN THE SW QUADRANT WITH SCATTERED MODERATE/STRONG
CONVECTION COVERING THE REMAINDER OF THE AREA FROM 14N-20N
BETWEEN 50W-56W.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 16N39W TO 8N34W MOVING W 15-20 KT.
WAVE IS AT THE LEADING EDGE OF AN AREA DEEP LAYER MOISTURE
MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY WHICH
CONTINUES TO BE DRAWN INTO THE CIRCULATION OF HURRICANE BILL
CAUSING THE TILTED AXIS. ISOLATED SHOWERS ARE WITHIN 60/75 NM OF
LINE FROM 15N43W TO 12N28W.

TROPICAL WAVE IS ALONG 79W/80W S OF 22N MOVING W NEAR 25 KT.
THIS WAVE RESULTED FROM THE REMNANTS OF ANA AND IS NOT
DISPLAYING THE TYPICAL CHARACTERISTICS OF A TROPICAL WAVE...SUCH
AS BEING EMBEDDED WITHIN DEEP LAYERED MOISTURE. IT IS IN AN AREA
OF DRY STABLE AIR AND NOT PRODUCING ANY SHOWERS/CONVECTION.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 13N16W 11N25W 12N34W THEN ALONG
10N38W 13N47W THEN ALONG 11N56W 9N62W. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS FROM 5N-8N BETWEEN 42W-45W.
CLUSTERS OF SIMILAR CONVECTION ARE 7N-13N BETWEEN 19W-26W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE COVERS THE W AND CENTRAL GULF WHILE A UPPER
LOW IN THE CARIBBEAN EXTENDS AN UPPER TROUGH OVER THE E GULF
PROVIDING ABUNDANCE OF UPPER LEVEL MOISTURE ACROSS THE ENTIRE
AREA. A WEAK SURFACE TROUGH EXTENDS FROM THE W YUCATAN PENINSULA
NEAR 19N90W TO OVER THE CENTRAL GULF TO 28N88W. SCATTERED
SHOWERS/THUNDERSTORMS ARE S OF 20N ACROSS THE ENTIRE BAY OF
CAMPECHE TO INLAND OVER MEXICO. ISOLATED SHOWERS DOT THE
REMAINDER OF THE GULF.

CARIBBEAN SEA...
THE MOST SIGNIFICANT FEATURE FOR THE CARIBBEAN TONIGHT IS THE
UPPER LOW CENTERED NEAR 20N83W COVERING THE NW CARIBBEAN AND
EXTENDING AN UPPER TROUGH N OVER THE E GULF OF MEXICO AND SE TO
NEAR 12N76W. THIS FEATURE IS GENERATING SCATTERED SHOWERS/
THUNDERSTORMS N OF 18N OVER CUBA AND THE YUCATAN CHANNEL BETWEEN
83W-87W AND ISOLATED SHOWERS/THUNDERSTORMS OVER THE SW CARIBBEAN
WITHIN 60 NM OF 11N FROM 75W-82W. FRESH TO STRONG EASTERLY TRADE
WINDS CONTINUE ACROSS THE AREA. DRY STABLE AIR ACROSS THE AREA E
OF 80W IS LIMITING ANY SHOWERS RESULTING IN FAIR CONDITIONS
TONIGHT ACROSS THE REMAINDER OF THE CARIBBEAN. HOWEVER...
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WILL BE
APPROACHING THE LEEWARD ISLANDS DURING THE NIGHT AS HURRICANE
BILL MOVES NW OF THE ISLANDS.

ATLANTIC OCEAN...
THE MAIN FOCUS TONIGHT FOR THE ATLC IS MAJOR HURRICANE BILL.
THE UPPER TROUGH OVER THE E GULF OF MEXICO AND NW CARIBBEAN
COVERS THE SW ATLC...AN UPPER RIDGE IS JUST TO THE E EXTENDING
FROM HISPANIOLA TO JUST W OF BERMUDA...AND TO THE E OF BERMUDA
IS AN UPPER LOW NEAR 32N61W. THIS SCENARIO IS PROVIDING
DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 23N-29N BETWEEN 76W TO JUST INLAND OVER THE
FLORIDA PENINSULA NEAR 81W WITH ISOLATED SHOWERS/THUNDERSTORMS
DOTTING THE AREA WITHIN 120 NM OF LINE FROM 28N76W TO 32N63W.
OTHERWISE THE ATLC BASIN IS DOMINATED BY A SURFACE RIDGE
ANCHORED BY A 1022 MB HIGH OVER THE W ATLC JUST N OF THE REGION
NEAR 33N73W AND BY A 1023 MB HIGH NEAR 30N32W IN THE E WITH A
WEAKNESS OVER THE CENTRAL ATLC COMPLIMENTS OF HURRICANE BILL.

$$
WALLACE





This weather bulletin was brought to you by:
www.nashvilleweather.net