[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 21 2010

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

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

...SPECIAL FEATURE...

A SURFACE TROUGH IS ALONG 26N70W IN THE ATLANTIC OCEAN TO THE
DOMINICAN REPUBLIC NEAR 18N72W. BROKEN TO OVERCAST MULTILAYERED
CLOUDS COVER THE AREA BETWEEN 60W AND 77W. STRONG SHOWERS AND
THUNDERSTORMS COVER THE CARIBBEAN SEA AND ATLANTIC OCEAN FROM
17N TO 22N BETWEEN 64W IN THE VIRGIN ISLANDS AND 77W IN JAMAICA.
AN UPPER LEVEL TROUGH GOES FROM 31N72W TO A 27N73W CYCLONIC
CIRCULATION CENTER...TO SOUTHEASTERN CUBA NEAR 20N77W TO JUST TO
THE SOUTH OF JAMAICA NEAR 17N77W. UPPER LEVEL ANTICYCLONIC FLOW
CURVES SOUTHEASTWARD...EVENTUALLY RUNNING INTO THE CYCLONIC FLOW
OF THE TROUGH/CYCLONIC FLOW THAT IS BETWEEN 50W AND 60W. DATA
FROM THE NOAA G-IV JET INDICATE THAT UPPER-LEVEL WINDS ARE NOT
CONDUCIVE FOR DEVELOPMENT AT THIS TIME...ALTHOUGH THEY MAY BECOME
MARGINALLY FAVORABLE IN A DAY OR TWO. LOCALLY HEAVY SHOWERS AND
GUSTY WINDS ASSOCIATED WITH THIS AREA OF WEATHER WILL SPREAD
ACROSS THE BAHAMAS...SECTIONS OF CUBA...AND SOUTHERN FLORIDA
DURING THE NEXT COUPLE OF DAYS AS THE SYSTEM MOVES WESTWARD OR
WEST-NORTHWESTWARD 10 TO 15 MPH. THE CHANCE THAT THIS SYSTEM MAY
BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS MEDIUM.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 15N37W TO 7N36W TO
3N35W...MOVING WEST 10 KT. IT IS NOT EASY TO DETERMINE WHICH
PRECIPITATION IS JUST ASSOCIATED WITH THIS WAVE AND WHICH
PRECIPITATION JUST IS ASSOCIATED WITH THE ITCZ. NO SIGNIFICANT
AND ORGANIZED DEEP CONVECTIVE PRECIPITATION IS NEAR THE WAVE.

A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 77W/78W TO THE
SOUTH OF 17N AND JAMAICA...MOVING WESTWARD 10 KT. NO SIGNIFICANT
AND ORGANIZED DEEP CONVECTIVE PRECIPITATION IS NEAR THE WAVE.

...THE ITCZ...

13N17W 9N28W 7N34W 7N44W 8N53W 10N61W. CYCLONIC FLOW IN THE
LOW CLOUDS OF THE DAY'S LAST VISIBLE IMAGERY BETWEEN 23W AND
27W IS BEING RELATED TO A TROPICAL WAVE THAT IS ALONG 25W/26W.
ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE
FROM 8N TO 10N BETWEEN 26W AND 32W...FROM 1N TO 2N BETWEEN
33W AND 35W...AND FROM 9N TO 12N BETWEEN 53W AND 57W. ISOLATED
MODERATE SHOWERS ARE ELSEWHERE TO THE SOUTH OF 10N BETWEEN 36W
AND 50W.

...DISCUSSION...

THE GULF OF MEXICO...
A SURFACE TROUGH CURVES FROM THE COASTAL PLAINS OF MEXICO...
IN THE SOUTHWESTERN GULF OF MEXICO...TO 24N96W AND 29N95W.
STRONG SHOWERS AND THUNDERSTORMS ARE IN THE NORTHEASTERN COASTAL
AREA OF THE YUCATAN PENINSULA...TO MEXICO AND WESTERN-BORDERING
GUATEMALA...INTO THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO
WITHIN A 60 NM RADIUS OF 20N93W...NORTHWARD BETWEEN 90W AND 100W
IN THE GULF WATERS. AN UPPER LEVEL CYCLONIC CENTER IS NEAR
27N99W ALONG THE TEXAS/MEXICO BORDER. UPPER LEVEL ANTICYCLONIC
OUTFLOW MOVES SOUTHEASTWARD...COVERING THE GULF OF MEXICO BETWEEN
84W AND 90W.

THE CARIBBEAN SEA...
CLOUDS...SHOWERS...AND THUNDERSTORMS COVER THE ATLANTIC OCEAN
AND THE CARIBBEAN SEA FROM 10N TO 17N BETWEEN 58W AND 67W...
INCLUDING THE EASTERN CARIBBEAN SEA ISLANDS. THE 24-HOUR
RAINFALL TOTAL FOR GUADELOUPE FOR 21/1200 UTC WAS 2.26 INCHES.
THIS AREA IS TO THE SOUTHWEST OF THE UPPER LEVEL 19N57W CYCLONIC
CIRCULATION CENTER...IN AN AREA OF DIFFLUENT UPPER LEVEL WIND
FLOW THAT IS HELPING TO INCREASE THE CLOUDS AND PRECIPITATION.
STRONG SHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING IN
NORTHWESTERN VENEZUELA TO THE EAST OF LAKE MARACAIBO...AND IN
NORTHERN COASTAL COLOMBIA TO THE NORTH OF 10N...IN BROAD LOW
PRESSURE THAT RUNS FROM THE SURFACE INTO THE LOWER LEVELS OF
THE ATMOSPHERE.

THE ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS ALONG 29N53W 23N56W...TO A POSSIBLE
CYCLONIC CENTER NEAR 19N57W...TO 11N54W. DRY AIR IN SUBSIDENCE
SURROUNDS THIS TROUGH. A SURFACE TROUGH IS ALONG 30N46W 24N44W
18N42W. BROKEN LOW CLOUDS AND POSSIBLE SHOWERS ARE TO THE NORTH
OF 12N BETWEEN 40W AND 50W. THIS SURFACE TROUGH USED TO BE THE
NORTHERN EXTENSION OF THE 15N37W 3N35W TROPICAL WAVE. AN UPPER
LEVEL TROUGH IS ALONG 31N10W TO 25N22W TO 22N27W...SURROUNDED
BY DRY AIR IN SUBSIDENCE.

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

$$
MT





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