[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 241059
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON 23 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 0600 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1015 UTC.

...SPECIAL FEATURE...

SATELLITE IMAGES INDICATE THAT THE THUNDERSTORM ACTIVITY
ASSOCIATED WITH A STRONG TROPICAL WAVE CENTERED ABOUT 575 MILES
WEST-SOUTHWEST OF THE CAPE VERDE ISLANDS IS GRADUALLY INCREASING
AND BECOMING BETTER ORGANIZED. CONDITIONS APPEAR TO BE FAVORABLE
FOR A TROPICAL CYCLONE TO FORM LATER TODAY OR WEDNESDAY AS THE
SYSTEM MOVES WESTWARD AT 15 MPH. SCATTERED STRONG SHOWERS AND
THUNDERSTORMS ARE WITHIN 40 TO 60 NM ON EITHER SIDE OF 12N28W
12N32W 9N33W. ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND
THUNDERSTORMS ELSEWHERE FROM 5N TO 10N BETWEEN 35W AND 41W.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 50W/51W SOUTH OF 17N MOVING WEST 20 KT. THIS
IS A CONFUSING WAVE WITH ONE PIECE OF IT APPARENTLY BREAKING OFF
TO FORM A CENTRAL ATLANTIC TROUGH...30N43W 25N44W 20N45W...WHILE
ANOTHER FEATURE CAN BE TRACKED IN THE ITCZ. ISOLATED MODERATE
SHOWERS FROM 26N TO 28N BETWEEN 40W AND 45W. COMPUTER MODELS
INDICATE THAT THE SOUTHERN PART OF THE WAVE...DENOTED BY THE
INCREASE IN ITCZ SHOWERS AND THUNDERSTORMS...WILL MOVE INTO
THE WINDWARD ISLANDS WEDNESDAY WITH ENHANCED RAINSHOWERS.

WESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 90W/91W SOUTH OF 17N
MOVING WEST 20 KT. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE
IN THE GULF OF TEHUANTEPEC NORTH OF 15N...AND FROM 11.5N TO 15N
BETWEEN 90W AND 94W. WESTERN EL SALVADOR AND SOUTHERN GUATEMALA
ARE BEING AFFECTED.

...ITCZ...
ITCZ 9N13W 7N26W 8N40W 9N48W 6N57W. ISOLATED MODERATE SHOWERS
FROM 7N TO 13N BETWEEN 40W AND 60W...NOT COUNTING THE SHOWERS
AND THUNDERSTORMS WITH THE TROPICAL WAVE ABOUT 575 NM WEST OF
THE CAPE VERDE ISLANDS.

...DISCUSSION...

THE GULF OF MEXICO...
UPPER LEVEL RIDGE FROM CENTRAL MEXICO TO CENTRAL TEXAS EASTWARD
TO LOUISIANA AND EVENTUALLY SOUTHEASTERN GEORGIA. MIDDLE TO
UPPER LEVEL TROUGH FROM EASTERN PACIFIC OCEAN NEAR 14N100W
TO CYCLONIC CIRCULATION CENTER IN NORTHWESTERN ISTHMUS OF
TEHUANTEPEC OF MEXICO TO SHORES OF NORTHWESTERN YUCATAN
PENINSULA. HIGH LEVEL MOISTURE FROM THE MEXICO-TO-TEXAS-TO
SOUTHEASTERN GEORGIA RIDGE COVERS THE GULF WATERS NORTH OF 27N
WHILE THE REST OF THE GULF WATERS SEE MIDDLE TO UPPER LEVEL
DRY AIR...SAVE FOR SOME MORE HIGH LEVEL MOISTURE IN THE
SOUTHWESTERN CORNER OF THE GULF AND THE YUCATAN PENINSULA SOUTH
OF 22N BETWEEN 90W AND 95W. ISOLATED MODERATE SHOWERS FROM
THE ATLANTIC OCEAN ADJACENT TO THE NORTHERN SHORES OF CUBA
NEAR 22N78W TO 26N83W. THIS PRECIPITATION IS ALONG THE WESTERN
PERIPHERY OF AN AREA OF MIDDLE TO UPPER LEVEL CYCLONIC
FLOW...WHICH IS RELATED TO AN ATLANTIC OCEAN-TO-NORTHERN
CARIBBEAN SEA TROUGH.

THE CARIBBEAN SEA...
UPPER LEVEL RIDGE WEST OF 80W SOUTH OF 20N WITH A DIFFLUENT
ENVIRONMENT...COMBINED WITH 86W/87W TROPICAL WAVE...TO GIVE
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 11.5N TO 15N
BETWEEN 88W AND 92W...ENCOMPASSING THE EASTERN PACIFIC COASTAL
AREAS OF NICARAGUA...WESTERN HONDURAS...EL SALVADOR...AND
SOUTHERN GUATEMALA. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS
ALSO ARE IN THE SOUTHWESTERN CORNER...SOUTH OF 12.5N BETWEEN
80W AND THE COSTA RICA/NICARAGUA BORDER...POSSIBLY DUE TO THE
ITCZ AND ANY REMAINING ENERGY FROM THE 90W/91W TROPICAL WAVE.
LITTLE CHANGE IS LIKELY FOR THE NEXT COUPLE DAYS AS THE UPPER
TROUGH SETTLES OVER THE CENTRAL CARIBBEAN.

SUBTROPICAL ATLANTIC OCEAN AND TROPICAL ATLANTIC WEST OF 50W...
THE WEATHER REMAINS MOSTLY QUIET IN THIS AREA WITH SPECKLES OF
SHOWER ACTIVITY PRESENT.. MOST NUMEROUS IN THE BAHAMAS.  UPPER
RIDGING EXTENDS FROM CENTRAL FLORIDA ENE TO BERMUDA WITH DRY
AIR/SUBSIDENCE S OF THE RIDGE AXIS TO 26N KEEPING THINGS CALM.
BROAD SURFACE RIDGE 30N64W 27N72W TO 25N82W IN THE STRAITS OF
FLORIDA. THE MID-OCEANIC TROUGH HAS TAKEN UP RESIDENCE IN THE
CENTRAL ATLC WITH ONE BIG UPPER LEVEL CYCLONIC CIRCULATION
CENTER NEAR 26N58W...AND ONE BEING STRETCHED NEAR 38N53W...THE
TROUGH WITH THESE CYCLONIC CENTERS EVENTUALLY REACHES THE
EASTERN CARIBBEAN SEA. SURFACE TROUGH 30N60W 25N62W 20N62W.
WIDELY SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND
THUNDERSTORMS WITHIN 30 TO 40 NM ON EITHER SIDE OF 32N53W 28N54W
25N54W. ISOLATED MODERATE SHOWERS ELSEWHERE NORTH OF 20N BETWEEN
50W AND 70W. CYCLONIC FLOW FROM THE MID-OCEANIC TROUGH STRETCHES
ALL THE WAY INTO THE DEEP TROPICS WITH MOSTLY SOUTH TO SOUTHWEST
FLOW IN THE TROPICAL ATLC AND VERY DRY AIR ALOFT. THE REMNANT
CIRCULATION OF DANIELLE IS CENTERED ABOUT 800 MILES
WEST-SOUTHWEST OF THE AZORES ISLANDS AND IS MOVING
NORTH-NORTHWESTWARD NEAR 10 MPH. SHOWER ACTIVITY ASSOCIATED
WITH THIS SYSTEM HAS DIMINISHED AND UPPER-LEVEL WINDS HAVE
BECOME UNFAVORABLE FOR RE-DEVELOPMENT.

SUBTROPICAL ATLANTIC OCEAN EAST OF 50W....
BENIGN WEATHER IN THE E ATLC WITH AN UPPER LEVEL ANTICYCLONIC
CIRCULATION CENTER NEAR 27N41W KEEPING THINGS DRY. OTHERWISE
A WEAKENING UPPER TROUGH ALONG 34N NORTH OF 21N SEPARATES THE
AFOREMENTIONED ANTICYCLONIC CENTER WITH BROAD ANTICYCLONIC FLOW
IN THE EASTERN ATLANTIC OCEAN. THE REMNANTS OF DANIELLE ARE
NORTH OF THE AREA NEAR 34N44W WITH OCCASIONAL THUNDERSTORMS
NEAR THE CENTER BUT SHEAR KEEPS THE SYSTEM FROM FURTHER
DEVELOPMENT.

TROPICAL ATLANTIC EAST OF 50W...
MODERATE/STRONG SUBSIDENCE IS THE RULE WEST OF 40W KEEPING A LID
ON ANY SIGNIFICANT CONVECTION. INCREASING MOISTURE IS PRESENT
FARTHER E IN ASSOCIATION WITH A STRONG TROPICAL WAVE WEST OF THE
CAPE VERDES. MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTER IS NEAR 20N34W WITH EASTERLY WINDS AND RELATIVELY LIGHT
SHEAR EAST OF 40W.

$$
MT




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