[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082336
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUL 08 2012

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
2245 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 20N22W TO 12N24W MOVING W AT 10-15 KT.
THE WAVE LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE
PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. THERE IS ALSO A
CLEARING IN THE LARGE AREA OF SAHARAN DUST AROUND THE WAVE
INDICATING ITS PRESENCE. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 8N-13N BETWEEN 20W-25W.

TROPICAL WAVE IS ALONG 27N54W TO 17N60W MOVING W NEAR 15 KT. THE
WAVE IS ON THE WRN SIDE OF AN AREA OF ENHANCED MOISTURE. THE
WAVE ALSO LIES ON THE LEADING EDGE OF A LARGE AREA OF SAHARAN
DUST THAT EXTENDS ACROSS MUCH OF THE TROPICAL ATLC. THE DUST IS
SUPPRESSING MOST CONVECTION NEAR THE WAVE EXCEPT FOR SOME WIDELY
ISOLATED MODERATE CONVECTION FROM 22N-26N BETWEEN 52W-56W.

TROPICAL WAVE IS EMERGING OFF THE YUCATAN PENINSULA ALONG 23N90W
TO 14N91W MOVING W NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY
INDICATES THAT THE WAVE LIES WITHIN A SURGE OF DEEP LAYER
MOISTURE COVERING THE YUCATAN PENINSULA AND SW GULF OF MEXICO.
SATELLITE IMAGERY ALSO SHOWS BROAD LOW-MID LEVEL CYCLONIC FLOW
IS AROUND THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS E OF
THE WAVE AXIS ACROSS THE YUCATAN PENINSULA FROM 18N-22N BETWEEN
86W-90W. SIMILAR ACTIVITY IS W OF THE WAVE FROM 17N-20N BETWEEN
93W-96W. SCATTERED STRONG CONVECTION IS NEAR THE SRN EXTENT OF
THE WAVE FROM 14N-16N BETWEEN 90W-94W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
SENEGAL AT 14N17W TO 10N27W. THE ITCZ BEGINS AT 10N27W TO A 1010
MB SURFACE LOW NEAR 7N43W CONTINUING TO 4N52W. A CLUSTER OF
STRONG CONVECTION IS MOVING OFF THE COAST OF AFRICA FROM 8N-12N
BETWEEN 13W-15W. ISOLATED MODERATE CONVECTION IS FROM 6N-9N
BETWEEN 28W-39W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS NEAR THE LOW CENTER FROM 5N-8N BETWEEN 39W-47W. SCATTERED
MODERATE CONVECTION IS FROM 5N-9N BETWEEN 47W-52W.

...DISCUSSION...

GULF OF MEXICO...
WEAK SURFACE RIDGING IS ACROSS THE GULF OF MEXICO AROUND A 1020
MB HIGH NEAR THE BIG BEND OF FLORIDA AT 29N85W. LIGHT
ANTI-CYCLONIC FLOW IS AROUND THE SURFACE RIDGE. DRY AIR ALOFT IS
KEEPING A GOOD PORTION OF THE BASIN UNDER MOSTLY FAIR CONDITIONS
WITH ONLY A FEW ISOLATED SHOWERS/THUNDERSTORMS IN THE CENTRAL
GULF. HOWEVER...SHOWERS/THUNDERSTORMS HAVE POPPED UP INLAND
ACROSS AREAS OF THE GULF COAST. SHOWERS/THUNDERSTORMS ARE ACROSS
S FLORIDA AND THE FLORIDA STRAITS DUE TO DIFFLUENCE ALOFT AROUND
AN UPPER LEVEL TROUGH OVER THE ERN GULF. SIMILAR ACTIVITY ALSO
COVERS PORTIONS OF LOUISIANA....TEXAS...MISSISSIPPI...AND
ALABAMA...DUE TO A SECOND UPPER LEVEL TROUGH THAT IS SANDWICHED
BETWEEN TWO LARGE UPPER RIDGES OVER THE ERN CONUS AND SW CONUS.
THE UPPER RIDGE OVER THE SW CONUS EXTENDS OVER THE NW GULF. A
SECOND UPPER LEVEL RIDGE OVER THE WRN CARIBBEAN COVERS THE SRN
GULF OF MEXICO. A TROPICAL WAVE IS MOVING OFF THE YUCATAN
PENINSULA SUPPORTING SHOWERS/THUNDERSTORMS ACROSS THE PENINSULA
AND SW GULF. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS.
SURFACE RIDGING WILL REMAIN ACROSS THE BASIN WHILE THE TROPICAL
WAVE NEAR THE YUCATAN PENINSULA CONTINUES WWD OVER THE SW GULF.
MOIST CONDITIONS ARE EXPECTED ACROSS THE SW GULF AS WELL AS
ACROSS INLAND PORTIONS OF THE GULF COAST.

CARIBBEAN SEA...
MOST OF THE MOISTURE ASSOCIATED WITH THE TROPICAL WAVE OVER THE
YUCATAN PENINSULA HAS MOVED W OF THE AREA. A FEW
SHOWERS/THUNDERSTORMS REMAIN NEAR THE ERN SIDE OF THE YUCATAN.
SHOWERS/THUNDERSTORMS ARE ALSO ACROSS WRN CUBA ASSOCIATED WITH
DIFFLUENCE ALOFT AROUND THE E SIDE OF AN UPPER LEVEL TROUGH OVER
THE ERN GULF OF MEXICO. UPPER LEVEL RIDGING COVERS MOST OF THE
WRN HALF OF THE CARIBBEAN. STRONG SHOWERS/THUNDERSTORMS COVER
SRN NICARAGUA...COSTA RICA...AND WRN PANAMA LIKELY DUE TO THE E
PACIFIC MONSOON TROUGH THAT EXTENDS ACROSS SRN COSTA RICA AND
PANAMA TO NRN COLOMBIA. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE
ALSO OVER HISPANIOLA AND PUERTO RICO MOSTLY ASSOCIATED WITH
DAYTIME HEATING AND INSTABILITY. THE ERN CARIBBEAN AND CENTRAL
CARIBBEAN WATERS ARE MOSTLY CLEAR DUE TO DRY AIR ALOFT AROUND AN
UPPER LEVEL RIDGE OVER THE NE CARIBBEAN. A WEAK INVERTED UPPER
TROUGH IS ACROSS THE CENTRAL CARIBBEAN BETWEEN THE TWO UPPER
RIDGES ACROSS THE ERN AND WRN SIDES. TRADEWIND FLOW OF 15-20 KT
IS ACROSS MUCH OF THE BASIN WITH WINDS REACHING 25 AND POSSIBLY
30 KT IN THE S CENTRAL CARIBBEAN. EXPECT LITTLE CHANGE OVER THE
NEXT 24 HOURS. A TROPICAL WAVE NE OF THE BASIN MAY IMPACT THE
NRN LESSER ANTILLES...BUT WILL LIKELY REMAIN MOSTLY N OF THE
BASIN.

ATLANTIC OCEAN...
A SMALL UPPER LEVEL TROUGH OVER THE ERN GULF OF MEXICO IS
PROVIDING DIFFLUENCE ALOFT ACROSS THE WRN BAHAMAS SUPPORTING
SCATTERED SHOWERS/THUNDERSTORMS W OF 78W. THE REMAINDER OF THE
WRN ATLC IS EXPERIENCING MOSTLY FAIR CONDITIONS DUE TO DRY AIR
ALOFT AROUND A BROAD UPPER RIDGE COVERING THE ERN CONUS AND W
ATLC. TO THE E...AN UPPER TROUGH EXTENDS FROM NEAR 29N57W TO
24N71W...BUT IS NOT CAUSING ANY SIGNIFICANT WEATHER. A SECOND
UPPER TROUGH EXTENDS ALONG 51W SUPPORTING ISOLATED
SHOWERS/THUNDERSTORMS 20N-28N BETWEEN 51W-58W. THIS ACTIVITY MAY
ALSO BE RELATED TO A TROPICAL WAVE. THE HAVE HAS BEEN MOSTLY DRY
FOR THE PAST FEW DAYS DUE TO A LARGE AREA OF DUST TRAILING IT.
THE UPPER TROUGH IS PROVIDING JUST ENOUGH LIFT TO PRODUCE SOME
OF THIS WEAK ACTIVITY. BROAD SURFACE RIDGING COVERS THE
REMAINDER OF THE CENTRAL AND ERN ATLC ANCHORED BY A 1030 MB
AZORES HIGH NEAR 41N33W. THE RIDGE IS SUPPORTED BY AN UPPER
LEVEL RIDGE OVER THE N CENTRAL ATLC. UPPER RIDGING ALSO COVERS
THE TROPICAL ATLC. AS MENTIONED PREVIOUSLY...A LARGE AREA OF
AFRICAN DUST EXTENDS BETWEEN THE WAVE IN THE CENTRAL ATLC AND
AROUND THE TROPICAL WAVE NEAR THE COAST OF AFRICA.

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

$$
WALTON





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