[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 240607 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...COR
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON 23 AUG 2004

CORRECTION FOR SATELLITE IMAGERY VALID TIME...0345 UTC...

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 0000 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0345 UTC.

...SPECIAL FEATURE...

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A LARGE TROPICAL WAVE
LOCATED ABOUT 400 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS HAVE
INCREASED THIS EVENING. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS
EXIST FROM 9N TO 12N BETWEEN 28W AND 33W. ISOLATED TO WIDELY
SCATTERED MODERATE/LOCALLY STRONG SHOWERS AND THUNDERSTORMS EXIST
FROM 5N TO 10N BETWEEN 34W AND 40W. ENVIRONMENTAL CONDITIONS
APPEAR TO BE FAVORABLE FOR DEVELOPMENT...AND THIS SYSTEM HAS
THE POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT
DAY OR TWO AS IT MOVES WESTWARD AT 10 TO 15 MPH.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 48W SOUTH OF 16N MOVING WEST 20 KT. THIS IS
A CONFUSING WAVE WITH ONE PIECE OF IT APPARENTLY BREAKING OFF TO
FORM A CENTRAL ATLANTIC TROUGH...29N39W 26N40W 17N41W...WHILE
ANOTHER FEATURE CAN BE TRACKED IN THE ITCZ. 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 86W/87W SOUTH OF 17N
MOVING WEST 20 KT. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS
WITHIN 40 TO 60 NM ON EITHER SIDE OF 8N86W 11N88W 12N88W 15N90W
FROM THE EASTERN PACIFIC OCEAN TO SOUTHERN GUATEMALA.

...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 JUST 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 86W/87W 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.
1020 MB SURFACE HIGH IS NEAR 27N68W S OF THE UPPER RIDGE AXIS.
THE MID-OCEANIC TROUGH HAS TAKEN UP RESIDENCE IN THE CENTRAL
ATLC WITH TWO BIG UPPER LOWS NEAR 34N53W AND 24N57W COMPRISING
THE TROUGH CONTINUING INTO THE LEEWARD ISLANDS.  THIS FEATURE
IS RATHER DEEP WITH SOME SURFACE REFLECTION AS A WEAK TROUGH
IS PRESENT ALONG 60W N OF 18N.  ISOLATED MODERATE IS N OF 23N
BETWEEN 50W-55W ASSOCIATED WITH LIFT/INSTABILITY ASSOCIATED WITH
THE MID-OCEANIC TROUGH.   CYCLONIC FLOW FROM THE MID-OCEANIC
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 SYSTEM HAS DIMINISHED AND UPPER-LEVEL WINDS HAVE BECOME
UNFAVORABLE FOR REDEVELOPMENT.

SUBTROPICAL ATLANTIC OCEAN EAST OF 50W....
BENIGN WEATHER IN THE E ATLC WITH AN UPPER HIGH NEAR 27N41W
KEEPING THINGS DRY.  OTHERWISE A WEAKENING UPPER TROUGH ALONG
34N N OF 21N SEPARATES THE AFOREMENTIONED HIGH WITH BROAD
ANTICYCLONIC FLOW IN THE E ATLC.  THE REMNANTS OF DANIELLE ARE N
OF THE AREA NEAR 33N44W WITH OCCASIONAL TSTMS NEAR THE CENTER
BUT SHEAR KEEPS THE SYSTEM FROM FURTHER DEVELOPMENT.

TROPICAL ATLANTIC E OF 50W...
MODERATE/STRONG SUBSIDENCE IS THE RULE W OF 40W KEEPING A LID ON
ANY SIGNIFICANT CONVECTION.  INCREASING MOISTURE IS PRESENT
FARTHER E IN ASSOCIATION WITH A STRONG TROPICAL WAVE W OF THE
CAPE VERDES.   MID/UPPER HIGH IS NEAR 20N34W WITH ELY WINDS AND
RELATIVELY LIGHT SHEAR E OF 40W.  UPPER DIVERGENCE CONTINUES TO
ENHANCE THE CAPE VERDE WAVE WITH CONSIDERABLY MORE TSTM ACTIVITY
TONIGHT THAN LAST NIGHT AT THIS TIME.

$$
MT




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