[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN AUG 20 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 33W/34W SOUTH OF 20N
MOVING WEST 20 KT. THIS WAVE IS NOT GENERATING ANY DEEP
CONVECTIVE PRECIPITATION ALONG IT AT THIS MOMENT. PRECIPITATION
IS IN THE ITCZ FROM 6N TO 10N BETWEEN 30W AND 42W. LOW CLOUDS
AND POSSIBLE SHOWERS ARE WITHIN 60 TO 90 NM ON EITHER SIDE OF
A LINE THAT CURVES FROM 14N44W TO 17N42W 19N40W 19N36W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 47W/48W SOUTH OF 20N
MOVING WEST 15 TO 20 KT. SAHARAN DUST WAS SEEN EAST OF THIS WAVE
IN EARLIER VISIBLE IMAGERY. NO DEEP CONVECTIVE PRECIPITATION.

A CARIBBEAN SEA TROPICAL WAVE IS PASSING PUERTO RICO ALONG
67W/68W SOUTH OF 18N MOVING WEST 10 TO 15 KT. THIS WAVE ALL
BY ITSELF REALLY DOES NOT APPEAR TO BE CAUSING ANY DEEP
CONVECTIVE PRECIPITATION. ONE CELL OF STRONG
SHOWERS/THUNDERSTORMS IS IN THE WATERS JUST WEST OF
PUERTO RICO RIGHT NOW.

A TROPICAL WAVE WAS ADDED TO THE 20/1800 UTC SURFACE MAP ANALYSIS
BASED ON HOVMOLLER DIAGRAMS/SATELLITE IMAGERY. IT IS IN THE
WESTERN CARIBBEAN SEA ALONG 81W/82W SOUTH OF 19N MOVING WEST
10 TO 15 KT. IT IS MOVING THROUGH THE AREA OF THE WESTERN
CARIBBEAN SEA WITH A MIXTURE OF FEATURES IN IT.

...THE ITCZ...
ITCZ 11N14W 9N23W 9N32W 9N35W 8N42W 9N47W 8N50W 7N59W.
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE OCCURRING FROM
12N TO 14N BETWEEN 14W AND 18W...FROM 11N TO 12N BETWEEN 17W
AND 19W...AND FROM 9N TO 10N BETWEEN 16W AND 18W. ALL THIS
CONVECTIVE PRECIPITATION EASILY ACCOMPANIES THE NEXT TROPICAL
WAVE THAT WILL HIT THE ATLANTIC OCEAN. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FOUND FROM 6N TO
10N BETWEEN 30W AND 48W. ISOLATED MODERATE SHOWERS ARE FOUND
ELSEWHERE FROM 6N TO 8N BETWEEN 20W AND 26W...AND FROM
6N TO 12N BETWEEN 48W AND 60W.

...DISCUSSION...
THE GULF OF MEXICO...THE ATLANTIC OCEAN WEST OF 70W...
AND THE NORTHWESTERN CARIBBEAN SEA NORTHWEST OF 20N78W 16N85W...
MIDDLE TO UPPER LEVEL LOW PRESSURE CENTERS ABOUND. THE FIRST
LOW CENTER IS IN THE WESTERN ATLANTIC OCEAN NEAR 28N79W.
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS
COVER THE BAHAMAS AND THE ATLANTIC WATERS NORTH OF THE BAHAMAS
FROM 24N TO 29N BETWEEN 76W AND 80W. SHOWERS AND THUNDERSTORMS
ARE SPREAD OVER FLORIDA FROM SOUTH FLORIDA TO SOUTH OF TAMPA
TO NORTH CENTRAL FLORIDA. A MIDDLE TO UPPER LEVEL LOW IN THE
SOUTHWESTERN CORNER OF THE AREA IS THE SECOND MOST WELL-DEFINED
LOW IN THE AREA. UPPER LEVEL ANTICYCLONIC FLOW FROM A RIDGE
PASSES FROM THE SOUTHEASTERN U.S.A. TO TEXAS AND NORTHERN
MEXICO NORTHWARD THROUGH ARIZONA AND NEW MEXICO. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED ALONG THE WESTERN COAST OF MEXICO
IN UPPER LEVEL DIFFLUENT FLOW BETWEEN THE RIDGE AND THE
SOUTHWESTERN GULF OF MEXICO LOW CENTER. SCATTERED STRONG
SHOWERS AND THUNDERSTORMS STRETCH FROM NORTHERN GUATEMALA
TO THE NORTHERN YUCATAN PENINSULA. SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS ARE IN THE ISTHMUS OF
TEHUANTEPEC ON THE SOUTHERN SIDE OF THE LOW CENTER. SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE IN THE
CENTRAL GULF OF MEXICO FROM 23N TO 27N BETWEEN 86W AND 92W...
WITH A NOT-SO-WELL-DEFINED MIDDLE TO UPPER LEVEL LOW PRESSURE
CENTER. WIDELY SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE NORTH OF 20N BETWEEN 80W AND WESTERN CUBA.
OTHER STRONG SHOWERS AND THUNDERSTORMS ARE IN CUBA AND ADJACENT
WATERS FROM 21N TO 22N BETWEEN 75W AND 78W. A SURFACE TROUGH
IS IN THE WATERS OF THE NORTHEASTERN CORNER OF THE GULF...
FROM A 1015 MB LOW PRESSURE CENTER IN SOUTHEASTERN GEORGIA.
THIS LOW CENTER HAD BEEN IN THE ATLANTIC WATERS 24 HOURS AGO.

THE REST OF THE CARIBBEAN SEA...
THE WEST CENTRAL CARIBBEAN SEA IS MIXTURE OF AT LEAST A FEW
FEATURES COMING TOGETHER AT THE SAME TIME. REMNANTS OF A MIDDLE
TO UPPER LEVEL LOW CENTER IN THE NORTHWESTERN CORNER OF THE AREA
FROM 24 HOURS AGO STILL ARE PRESENT. ADD TO THAT SOME MIDDLE TO
UPPER LEVEL FLOW WHICH PASSES OVER THE ISTHMUS OF TEHUANTEPEC TO
THE SOUTH OF A SOUTHWESTERN GULF OF MEXICO LOW CENTER...REACHES
THE YUCATAN PENINSULA...AND CURVES SOUTHWARD OVER NICARAGUA
TOWARD COSTA RICA. ADD TO THAT AN UPPER LEVEL RIDGE ALONG
78W/79W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS WERE EVIDENT
AT 20/1845 UTC FROM 13N TO 15N BETWEEN 77W AND 80W. THE CLOUD
TOP TEMPERATURES HAVE WARMED IN MUCH OF THAT AREA SINCE THAT
TIME. THE COLDEST CLOUD TOP TEMPERATURES AND STRONG
THUNDERSTORMS ARE FOUND NOW FROM 15N TO 17N BETWEEN 78W AND 79W.
OTHER ISOLATED MODERATE SHOWERS AND THUNDERSTORMS ARE FOUND
FROM 16N TO 20N BETWEEN 74W AND 80W. THE NORTHEASTERN CORNER OF
THE AREA STILL IS UNDER THE INFLUENCE OF A MIDDLE TO UPPER LEVEL
TROUGH THAT ORIGINATES IN THE ATLANTIC OCEAN...THROUGH 26N62W TO
22N64W TO 20N66W. MIDDLE TO MOSTLY UPPER LEVEL EASTERLY FLOW
MOVES INTO THE REST OF THE CARIBBEAN SEA FROM THE ATLANTIC OCEAN.

THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH 32N60W TO 26N62W
22N64W TO 20N66W. ISOLATED MODERATE SHOWERS AND POSSIBLE
THUNDERSTORMS ARE IN THE ATLANTIC OCEAN FROM 22N TO 31N BETWEEN
51W AND 66W. A SURFACE TROUGH IS ALONG 30N56W 25N62W 20N66W.
MIDDLE TO UPPER LEVEL DRY AIR IS EAST OF 32N37W 23N50W 15N60W.
A MIDDLE TO UPPER LEVEL TROUGH GOES FROM ONE LOW PRESSURE CENTER
NEAR 33N24W TO A SECOND ONE NEAR 28N30W TO A THIRD ONE NEAR
23N42W. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE REST
OF THE ATLANTIC OCEAN NORTH OF 20N. BROAD SURFACE ANTICYCLONIC
WIND FLOW IS IN THE ATLANTIC OCEAN ON EITHER SIDE OF THE 30N56W
20N66W TROUGH.

$$
MT


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