[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 211812
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT 21 AUG 2004

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 1200 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1745 UTC.

...SPECIAL FEATURE...
TROPICAL DEPRESSION DANIELLE CENTER NEAR 30.7N 39.1W...OR
ABOUT 855 MILES...1375 KM...WEST-SOUTHWEST OF THE AZORES...
AT 21/1500 UTC. IT IS MOVING WEST 3 KT. THE MAXIMUM SUSTAINED
WIND SPEED IS 25 KT G 35 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1009 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
DANIELLE IS BECOMING A BROAD AREA OF LOW PRESSURE. DANIELLE
CONSISTS OF A TIGHT SWIRL OF LOW CLOUDS VOID OF DEEP CONVECTION.
GLOBAL MODELS SUGGEST THAT THE UPPER-LEVEL WINDS WILL REMAIN
UNFAVORABLE FOR DEVELOPMENT...THEREFORE DANIELLE SHOULD
DEGENERATE INTO A REMNANT LOW LATER TODAY. IT IS LIKELY THAT
THE REMNANT WILL BE ABSORBED BY AN APPROACHING COLD FRONT BY
72 HOURS. THERE WILL NOT BE ANY MORE ADVISORIES ISSUED BY THE
NATIONAL HURRICANE CENTER UNLESS REGENERATION OCCURS.

...TROPICAL WAVES...
TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS ALONG 30W
SOUTH OF 20N MOVING WEST 10 TO 15 KT. THE SURFACE LOW PRESSURE
CENTER ALONG THE WAVE AT 21/0600 UTC IS NOT FOUND AT THIS TIME.
ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS
FROM 6N TO 10N BETWEEN 16W AND 20W. BROKEN TO OVERCAST
MULTILAYERED CLOUDS WITH THIS WAVE FROM 2N TO 20N BETWEEN
10W AND 30W.

TROPICAL WAVE ALONG 67W/68W SOUTH OF 17N MOVING WEST 20 TO
25 KT. SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 14.5N
TO 16N BETWEEN 65.5W AND 68W. BROKEN TO OVERCAST MULTILAYERED
CLOUDS AND ISOLATED MODERATE SHOWERS/THUNDERSTORMS COVER THE
EASTERN CARIBBEAN SEA SOUTH OF 19N EAST OF 72W. AN ARC CLOUD
WITH SHOWERS AND THUNDERSTORMS WITHIN 10 NM ON EITHER SIDE OF
17N71W 16N73W 14.5N73W...MOVING NORTHWEST ABOUT 30 KT TOWARD
THE SOUTHERN SHORES OF HISPANIOLA...NEAR THE BARAHONA PENINSULA.

WESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 81W/82W SOUTH OF 18N
MOVING WEST 20-25 KT. SCATTERED STRONG SHOWERS AND THUNDERSTORMS
FROM 9.5N TO 11N BETWEEN 80W AND 82W...AND FROM 10.5N TO 12N
BETWEEN 83W AND 85W IN SOUTHEASTERN NICARAGUA AND NORTHERN COSTA
RICA ALONG ITS BORDER WITH NICARAGUA. IT IS POSSIBLE THAT THE
AFOREMENTIONED PRECIPITATION IN THE SOUTHWESTERN CARIBBEAN SEA
MIGHT BE MORE RELATED TO THE ITCZ...AND IT MIGHT BE ENHANCED
BY THIS WAVE.

...ITCZ...
ITCZ AXIS IS ALONG 11N13W 9N20W 11N28W 7N43W 12N65W 11N68W.
A FEW CELLS OF SHOWERS/THUNDERSTORMS FROM 12N TO 13N BETWEEN
30W AND 33W. ISOLATED MODERATE SHOWERS AND LOCALLY STRONG
THUNDERSTORMS FROM 7N TO 10N BETWEEN 38W AND 48W.

...DISCUSSION...
THE GULF OF MEXICO...
UPPER LEVEL WEST TO SOUTHWEST WIND FLOW FROM THE EASTERN PACIFIC
OCEAN...ACROSS INTERIOR MEXICO...CONTINUING INTO THE UNITED
STATES GULF COAST STATES...FROM SOUTH CENTRAL TEXAS TO NORTH
CENTRAL FLORIDA...FROM 28N TO 32N BETWEEN 81W AND 100W.
UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO FROM NORTHEASTERN
FLORIDA TO THE SOUTHWESTERN CORNER OF THE GULF. A SURFACE
STATIONARY FRONT GOES FROM NORTHEAST TEXAS THROUGH 33N95W TO
31N97W TO 30N104W. A WEAK SURFACE TROUGH RUNS FROM LOUISIANA
NEAR 32N91W TO THE NORTHWESTERN GULF WATERS NEAR 28N93W.
A WEAK SURFACE PRESSURE GRADIENT EXISTS IN THE GULF OF MEXICO.
LAKE OKEECHOBEE THROUGH THE FLORIDA KEYS AND INTO NW CUBA. THIN
WEDGE OF DRIER MIDDLE LEVEL AIR NOTED IN WATER VAPOR IMAGERY
EXTENDS WITHIN 180 NM EITHER SIDE OF TROUGH AXIS INTO CENTRAL
FLORIDA. E OF THIS TROUGH AXIS...BROAD AREA OF SCATTERED SHOWERS
AND ISOLATED TSTMS AREA FOUND IN AN AREA OF WEAK DIFFLUENCE
ALOFT.

THE SUBTROPICAL ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL TROUGH THROUGH 31N75W TO THE NORTHERN
BAHAMAS NEAR 27N78W TO THE STRAITS OF FLORIDA NEAR 24N81W...TO
THE EAST CENTRAL YUCATAN PENINSULA COAST NEAR 19N88W. ISOLATED
MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS COVER THE
NORTHERN HALF OF THE BAHAMAS FROM 23N TO 27N BETWEEN 76W AND
80W...AND IN THE NORTHWESTERN CARIBBEAN SEA NORTH OF 18N WEST OF
80W. OTHER ISOLATED MODERATE SHOWERS AND THUNDERSTORMS ARE JUST
SOUTH OF THE SOUTHEASTERN PART OF CUBA NORTH OF 19N...AT THE
EDGE OF AN AREA OF UPPER LEVEL RIDGE ALONG 71W/72W FROM
HISPANIOLA TO 30N. ISOLATED MODERATE SHOWERS/THUNDERSTORMS
FROM 26N TO 30N BETWEEN 70W AND 74W...EAST OF THE 31N75W 19N88W
TROUGH. UPPER LEVEL ANTICYCLONIC FLOW NEAR THE 67W/68W TROPICAL
WAVE FROM 14N TO 20N BETWEEN 53W AND 72W...MOSTLY COVERING THE
EASTERN CARIBBEAN SEA. SCATTERED TO BROKEN HIGH CLOUDS HAVE BEEN
DEVELOPING FROM 21N TO 26N BETWEEN 55W AND 60W...NEAR A WEAK
UPPER LEVEL TROUGH ALONG 27N58W 20N61W. DEEP LAYER CYCLONIC
CIRCULATION CENTER NEAR 33N52W...1018 MB LOW PRESSURE CENTER NEAR
35N56W...CONNECTED TO SURFACE FRONTAL BOUNDARY NORTH OF THE AREA.
TROUGH...SURROUNDED BY MIDDLE TO UPPER LEVEL DRY AIR...WITHIN
120 TO 180 NM ON EITHER SIDE OF 26N31W 19N36W 13N39W.

THE CARIBBEAN SEA...
SOUTHERN END OF A MIDDLE TO UPPER LEVEL TROUGH REACHES THE EAST
CENTRAL YUCATAN PENINSULA COAST NEAR 19N88W. UPPER LEVEL
ANTICYCLONIC FLOW NEAR THE 67W/68W TROPICAL WAVE FROM 14N TO 20N
BETWEEN 53W AND 72W...MOSTLY COVERING THE EASTERN CARIBBEAN SEA.
ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS
COVER THE NORTHWESTERN CARIBBEAN SEA NORTH OF 18N WEST OF 80W.
OTHER ISOLATED MODERATE SHOWERS AND THUNDERSTORMS ARE JUST SOUTH
OF THE SOUTHEASTERN PART OF CUBA NORTH OF 19N...AT THE EDGE OF
AN AREA OF UPPER LEVEL RIDGE ALONG 71W/72W FROM HISPANIOLA TO
30N. BROAD AREA OF MIDDLE TO UPPER LEVEL CYCLONIC FLOW IN THE
SOUTHWESTERN CORNER OF THE AREA...RIGHT NEXT TO UPPER LEVEL
ANTICYCLONIC FLOW FROM HONDURAS CURVING TO SOUTHEASTERN
NICARAGUA.

TROPICAL ATLANTIC...
STRONG MID/UPPER SUBSIDENCE IS CAPPING CONVECTION ASIDE FROM
ITCZ AND W AFRICAN TROPICAL SQUALL. DRY AIR STRETCHES ACROSS
THE ENTIRE AREA WITH STRONGEST SUBSIDENCE FOUND FROM 14N TO 25N
BETWEEN 30W AND 40W IN ASSOCIATION WITH A WESTWARD MOVING MIDDLE
TO UPPER LEVEL CIRCULATION CENTERED NEAR 16N35W. THE CLOUDS AND
REMAINING PRECIPITATION ASSOCIATED WITH NEXT TROPICAL WAVE
INLAND OVER AFRICA HAVE EMERGED FROM THE COAST.

$$
MT




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