[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212343
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 21 2011

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2300 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BRET IS CENTERED NEAR 34.2N 69.7W AS OF 2100 UTC
MOVING ENE AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007
MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT.
PUBLIC ADVISORIES ON BRET ARE ISSUED UNDER WMO HEADER WTNT32
KNHC AND UNDER AWIPS HEADER MIATCPAT2. FORECAST/ ADVISORIES ARE
ISSUED UNDER WMO HEADER WTNT22 KNHC AND UNDER AWIPS HEADER
MIATCMAT2. SCATTERED MODERATE CONVECTION IS S OF THE CENTER FROM
32N-34N BETWEEN 70W-73W...AND FROM 27N-31N BETWEEN 66W-70W.

TROPICAL STORM CINDY IS CENTERED NEAR 42.3N 45.0W AS OF 2100 UTC
MOVING NE AT 24 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002
MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT.
PUBLIC ADVISORIES ON CINDY ARE ISSUED UNDER WMO HEADER WTNT33
KNHC AND UNDER AWIPS HEADER MIATCPAT3. FORECAST/ADVISORIES ARE
ISSUED UNDER WMO HEADER WTNT23 KNHC AND UNDER AWIPS HEADER
MIATCMAT3. SCATTERED MODERATE CONVECTION IS FROM 41N-43N BETWEEN
43W-48W.

...TROPICAL WAVES...

TROPICAL WAVE IN THE ERN TRPCL ATLC EXTENDS S OF THE CAPE VERDE
ISLANDS ALONG 13N25W TO 5N28W MOVING W AT 15-20 KT. SATELLITE
IMAGERY AND SATELLITE DERIVED WINDS INDICATE CLEAR CYCLONIC FLOW
IS AROUND THE WAVE AXIS. WHILE THERE IS NOT A RIDGE OF DEEP
LAYER MOISTURE ASSOCIATED WITH THE WAVE...ENHANCED VALUES ARE
SURROUNDING THE AXIS. SCATTERED MODERATE/STRONG CONVECTION IS
FROM 10N-12N BETWEEN 26W-28W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 6N-8N BETWEEN 23W-30W.

TROPICAL WAVE EXTENDS E OF THE WINDWARD ISLANDS ALONG 17N49W
11N52W 7N52W MOVING W NEAR 20 KT. SATELLITE IMAGERY INDICATES
BROAD CYCLONIC FLOW IS AROUND THE WAVE AXIS. TOTAL PRECIPITABLE
WATER IMAGERY ALSO SHOWS A SURGE OF DEEP LAYER MOISTURE IS
AROUND THE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 12N-19N BETWEEN 46W-53W.

TROPICAL WAVE IS ACROSS THE NW CARIBBEAN AND WRN CUBA ALONG
24N81W TO 17N82W MOVING WNW NEAR 15 KT. THE WAVE IS EMBEDDED
WITHIN WIDESPREAD MODERATE MOISTURE ACROSS MUCH OF THE WRN
CARIBBEAN. WAVE LOCATION IS DIFFICULT TO DETERMINE AND IS
CURRENTLY BASED ON CONTINUITY AND SURFACE OBSERVATIONS IN THE NW
CARIBBEAN. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM EITHER
SIDE OF THE WAVE AXIS. STRONGER ACTIVITY IS ALL ACROSS CUBA AS
WELL. HOWEVER...THIS IS MORE A RESULT OF DAYTIME HEATING THAN
THE WAVE.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 16N ALONG 15N4W 17N12W ACROSS SENEGAL TO 11N22W. THE ITCZ
PICKS UP ON THE OTHER SIDE OF A TROPICAL WAVE ALONG 7N31W TO
7N45W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 2N-7N BETWEEN
30W-40W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
4N-7N BETWEEN 44W-49W.

...DISCUSSION...

GULF OF MEXICO...
MUCH OF THE GULF OF MEXICO IS UNDER FAIR WEATHER THIS EVENING
DUE TO THE COMBINATION OF WEAK SURFACE RIDGING ALONG 26N AND DRY
AIR ALOFT AROUND AN UPPER LEVEL RIDGE CENTERED OVER TENNESSEE.
LIGHT ANTI-CYCLONIC FLOW IS AROUND THE RIDGE WITH STRONGER SE
WINDS UP TO 20 KTS ACROSS THE NE MEXICO COAST. TYPICAL AFTERNOON
SHOWERS/THUNDERSTORMS ARE STILL ACROSS PORTIONS OF S FLORIDA DUE
TO DAYTIME HEATING. A FEW ISOLATED SHOWERS ARE IN THE NE GULF N
OF 26N E OF 91W. A TROPICAL WAVE S OF THE FLORIDA PENINSULA
ACROSS WRN CUBA AND THE NW CARIBBEAN MAY ENHANCE CONVECTION
ACROSS THE SE GULF AND YUCATAN PENINSULA OVER THE NEXT DAY OR SO
AS IT MOVES W OR WNW. WEAK SURFACE RIDGING IS EXPECTED TO REMAIN
ACROSS THE REMAINDER OF THE BASIN.

CARIBBEAN SEA...
A TROPICAL WAVE IN THE NW CARIBBEAN IS BRINGING A FEW ISOLATED
SHOWERS/THUNDERSTORMS TO THIS AREA N OF 17N BETWEEN 80W-84W.
STRONGER SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF CUBA DUE TO
DAYTIME HEATING. SOME OF THIS ACTIVITY MAY BE ENHANCED BY AN
UPPER LEVEL LOW THAT IS SPINNING OVER ERN CUBA NEAR 20N75W. A
WEAK UPPER TROUGH IS ALSO OVER THE WINDWARD ISLANDS...BUT IS
EMBEDDED WITH VERY DRY AIR. THIS DRY AIR IS MAINTAINING MOSTLY
FAIR WEATHER ACROSS THE REMAINDER OF THE BASIN. A FEW AFTERNOON
CONVECTIVE SHOWERS/THUNDERSTORMS ARE ACROSS HISPANIOLA AND
PUERTO RICO. SIMILAR ACTIVITY IS ACROSS
HONDURAS...NICARAGUA...AND PANAMA. SOME OF THE ACTIVITY ACROSS
PANAMA IS INFLUENCED BY THE MONSOON TROUGH EXTENDING FROM THE E
PACIFIC ACROSS COSTA RICA TO NRN COLOMBIA. ELY TRADEWINDS OF
20-25 KTS ARE ACROSS MUCH OF THE ERN CARIBBEAN. EXPECT THE
TROPICAL WAVE IN THE NW CARIBBEAN TO MOVE OUT OF THE AREA OVER
THE NEXT DAY OR. A TROPICAL WAVE E OF THE WINDWARD ISLANDS WILL
PROBABLY BEGIN IMPACTING THE ISLANDS WITHIN THE NEXT 24 HRS
BRINGING SHOWERS/THUNDERSTORMS...SOME HEAVY AT TIMES.

ATLANTIC OCEAN...
EVEN THOUGH TROPICAL STORM BRET IS N OF THE DISCUSSION
AREA...SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE SYSTEM ARE
IMPACTING THE AREA N OF 26N BETWEEN 64W-72W. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE NW BAHAMAS. THE
REMAINDER OF THE BASIN IS DOMINATED BY A BROAD SURFACE RIDGE
ANCHORED AROUND A 1032 MB AZORES HIGH NEAR 39N32W PROVIDING FAIR
WEATHER BASIN-WIDE. ALOFT...AN UPPER LEVEL RIDGE EXTENDS OVER
THE FAR WRN ATLC FROM THE ERN CONUS. AN UPPER LEVEL TROUGH IS TO
THE E N OF 29N. AN UPPER LEVEL RIDGE EXTENDS FROM NEAR 46N36W TO
AN ANTI-CYCLONIC CENTER NEAR 21N49W. AN UPPER TROUGH EXTENDS
FROM THE AZORES ISLANDS TO NEAR 24N38W. A SECOND ANTI-CYCLONIC
CENTER IS JUST N OF THE CAPE VERDE ISLANDS NEAR 21N26W...WHILE
ANOTHER UPPER LEVEL TROUGH COVERS THE FAR E ATLC EXTENDING FROM
PORTUGAL TO THE CANARY ISLANDS.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON





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