[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 101059
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT SEP 10 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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 FEATURES...

HURRICANE OPHELIA WEAKENED ENOUGH AND WAS DOWNGRADED TO TROPICAL
STORM OPHELIA AT 10/0900 UTC. THE CENTER OF TROPICAL STORM
OPHELIA IS NEAR 31.2N 76.8W AT 10/0900 UTC MOVING NORTHEAST
9 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 MB. THE
MAXIMUM SUSTAINED WIND SPEEDS ARE 60 KT WITH GUSTS TO 75 KT.
PLEASE REFER TO THE LATEST NHC FORECAST/ ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 31N TO 32N
BETWEEN 76W AND 77W. SCATTERED MODERATE SHOWER TO ISOLATED
STRONG THUNDERSTORMS FROM 32N TO 34N BETWEEN 72W AND 77W.

THE CENTER OF TROPICAL STORM NATE IS NEAR 34.8N 48.1W
AT 10/0900 UTC MOVING EAST 15 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 997 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 45 KT
WITH GUSTS TO 55 KT. PLEASE REFER TO THE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE
DETAILS. NATE CONSISTS ONLY OF A SWIRL OF LOW-LEVEL CLOUDS.
A TROUGH IS SOUTH AND SOUTHWEST OF THE CIRCULATION AROUND NATE.
ISOLATED MODERATE SHOWERS AND LOCALLY STRONG THUNDERSTORMS ARE
WITHIN 15 TO 30 NM ON EITHER SIDE OF 31N43W 28N50W 26N60W.

THE CENTER OF TROPICAL STORM MARIA IS NEAR 43.6N 38.6W AT
10/0900 UTC MOVING NORTHEAST 15 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 989 MB. THE MAXIMUM SUSTAINED WIND SPEEDS
ARE 50 KT WITH GUSTS TO 60 KT. PLEASE REFER TO THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS. SCATTERED MODERATE SHOWERS FROM 41N TO 49N
BETWEEN 34W AND 42W.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 30W/31W SOUTH OF 22N MOVING
WEST 15 KT WITH A WEAK AND ILL-DEFINED 1012 MB NEAR 10.5N. NO
DEEP CONVECTIVE ACTIVITY ACCOMPANIES THIS WAVE.

TROPICAL WAVE ALONG 57W/58W SOUTH OF 22N MOVING WEST 15 KT.
ISOLATED MODERATE SHOWERS...WHICH REALLY MAY HAVE NOTHING
TO DO WITH THIS WAVE...FROM 15N TO 20N BETWEEN 50W AND 60W.

EASTERN CARIBBEAN SEA TROPICAL WAVE ALONG 70W/71W SOUTH OF 20N
MOVING WEST 15 KT. THE WAVE CONTINUES TO INTERACT WITH AN UPPER
LEVEL ATLANTIC OCEAN LOW PRESSURE CENTER WITHIN 300 NM OF THE
NORTHERN COAST OF THE DOMINICAN REPUBLIC. CONVECTIVE DEBRIS
CLOUDS FROM ALREADY WEAKENED SHOWER AND THUNDERSTORM ACTIVITY
IS NORTH OF 17N BETWEEN THE HAITI/DOMINICAN REPUBLIC BORDER
AND JAMAICA. SOME REMAINING STRONG THUNDERSTORMS ARE ALONG
THE NORTHEASTERN SHORES OF JAMAICA. SHOWERS AND THUNDERSTORMS
RELATED TO THE UPPER LEVEL LOW ARE ABOUT 110 NM NORTHEAST
OF THE SOUTHERN BAHAMAS.

WESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 85W SOUTH OF 20N
MOVING WEST 15 TO 20 KT. THIS WAVE IS ALSO INTERACTING
WITH A LARGE UPPER LEVEL NORTHWESTERN CARIBBEAN SEA LOW PRESSURE
CENTER. THE SHOWERS AND THUNDERSTORMS ALONG THE HONDURAS COAST
MAY BE RELATED TO THE UPPER LEVEL LOW THAN TO THE WAVE. THE
STRONG SHOWERS AND THUNDERSTORMS IN THE SOUTHWESTERN CORNER OF
THE CARIBBEAN SEA MAY BE MORE RELATED TO THE ITCZ THAN ANYTHING
ELSE. IT IS NOT EASY TO FIND PRECIPITATION DIRECTLY AND ONLY
RELATED TO THIS WAVE.

...ITCZ...

ITCZ 10N10W 8N28W 8N32W 8N47W 8N62W. SCATTERED MODERATE TO
STRONG SHOWERS AND THUNDERSTORMS FROM 6N TO 10N BETWEEN 50W
AND 56W. ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND
THUNDERSTORMS ELSEWHERE FROM 6N TO 14N BETWEEN AFRICA AND 50W.

...DISCUSSION...

GULF OF MEXICO...
ONE UPPER LEVEL LOW PRESSURE CENTER IS IN THE NORTHWESTERN
CARIBBEAN SEA. A SECOND UPPER LEVEL LOW PRESSURE CENTER IS IN
NORTH CENTRAL MEXICO. THE UPPER FLOW IS PRIMARILY DOMINATED BY
THE EASTERN UPPER LOW WITH N/NE WINDS EXTENDING S OF 27N INTO
THE BAY OF CAMPECHE AND YUCATAN PENINSULA. THE WESTERN LOW OVER
MEXICO IS HELPING TO MOVE TROPICAL PACIFIC MOISTURE OVER THE
EASTERN HALF OF MEXICO AND THE FAR WESTERN GULF. SCATTERED
MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ARE NORTH OF 23N
BETWEEN 95W AND THE MEXICO/TEXAS COASTS...IN AN AREA OF BROAD
SURFACE LOW PRESSURE AND A WEAK SURFACE TROUGH. ISOLATED
MODERATE SHOWERS ARE TRICKLING INTO THE YUCATAN CHANNEL
AREA...ON THE NORTHERN SIDE OF THE UPPER LEVEL NORTHWESTERN
CARIBBEAN SEA LOW PRESSURE CENTER.

CARIBBEAN...
THE LARGE NORTHWESTERN CARIBBEAN SEA UPPER LOW OVER THE NW
CARIBBEAN NEAR 19N84W HAS BEEN PRESENTED ALREADY WITH REGARD
TO GULF OF MEXICO WEATHER AND THE TROPICAL WAVE ALONG 83W.
SHOWERS AND THUNDERSTORMS. SHOWERS AND THUNDERSTORMS IN CENTRAL
AMERICA AND IN THE CARIBBEAN SEA FROM 10N TO 20N WEST OF 80W
HAVE BEEN RELATED TO THE 83W WAVE. SOME SHOWERS ARE ON TOP OF
HAITI AND SOME ARE IN THE EASTERN CARIBBEAN SEA.

WEST ATLANTIC...
AN UPPER LEVEL LOW IS CENTERED NORTH OF THE DOMINICAN REPUBLIC
REPUBLIC NEAR 24N71W MOVING QUICKLY NORTHWESTWARD...AND IS
PRODUCING SCATTERED SHOWERS/THUNDERSTORMS FROM THE SOUTHERN
BAHAMAS ISLANDS TO 30N BETWEEN 60W AND 75W.

EAST/CENTRAL ATLANTIC...
A LARGE UPPER LEVEL HIGH IS CENTERED OVER THE CENTRAL ATLC
WATERS NEAR 28N50W WITH A RIDGE AXIS EXTENDING WWD TOWARDS
OPHELIA AND SWWD TOWARDS THE LESSER ANTILLES. A SURFACE TROUGH
EXTENDING SOUTH OF T.S. NATE WAS PRODUCING A FEW SHOWERS EARLIER
TODAY BUT THE SUBSIDENCE ASSOCIATED WITH THE UPPER HIGH JUST
ABOUT HAS STOPPED THAT DEVELOPMENT. THE HIGH IS QUITE EXPANSIVE
AND IS DRIVING DEEP EASTERLIES ACROSS THE TROPICS FROM THE CAPE
VERDES TO THE LESSER ANTILLES. A STATIONARY UPPER LEVEL TROUGH
EXTENDS FROM NEAR THE CANARY ISLANDS SW TO 20N27W AND IS BEING
REINFORCED BY A WEAK UPPER LOW DROPPING DOWN THE BACK SIDE OF
THE TROUGH NEAR 20N36W. WHILE MOST OF THE AREA IS FREE OF ANY
WIDESPREAD AREAS OF DEEP CONVECTION...SKIES ARE PROBABLY RATHER
HAZY AND MILKY DUE TO A LARGE AREA OF SAHARAN DUST EXTENDING
ACROSS THE ENTIRE AREA...AND A LARGE CANOPY OF HIGH LEVEL CIRRUS
EXTENDING N OF 25N BETWEEN 23W-50W.

$$
MT




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