[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

RECONNAISSANCE AIRCRAFT LATE THIS MORNING DETERMINED THE OPHELIA
ONCE AGAIN RE-STRENGTHENED INTO A HURRICANE. OPHELIA IS CENTERED
NEAR 31.7N 76.2W...ABOUT 225 M ESE OF CHARLESTON SOUTH CAROLINA
AT 10/1800 UTC. OPHELIA IS MOVING NORTHEAST AT 3 KT. MINIMUM
CENTRAL PRESSURE IS 977 MB AND THE MAXIMUM SUSTAINED WIND SPEED
IS 70 KT WITH GUSTS TO 85 KT. PLEASE REFER TO THE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS. THE CLOUD PATTERN ASSOCIATED WITH OPHELIA
REMAINS WELL ORGANIZED WITH A RAGGED EYE FEATURE DISCERNIBLE IN
VISIBLE SATELLITE IMAGES. HOWEVER...DURING THE PAST FEW HOURS
CLOUDS TOPS HAVE WARMED OVER THE NW QUADRANT. SCATTERED TO
NUMEROUS MODERATE CONVECTION IS WITHIN 100 NM OF CENTER.
SCATTERED MODERATE CONVECTION IS ALSO LOCATED FROM 31N-35N
BETWEEN 72W-75W.

TROPICAL STORM NATE IS CENTERED NEAR 34.6N 44.8W AT 10/1500 UTC
MOVING EAST 20 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 998
MB. THE MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50
KT. PLEASE REFER TO THE LATEST NHC FORECAST/ ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. NATE
IS BECOMING EXTRATROPICAL AND CONSISTS OF A SWIRL OF LOW CLOUDS
WITH NO DEEP CONVECTION.  FUTURE INFORMATION ON THE REMNANTS OF
NATE CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE OCEAN
PREDICTION CENTER UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER
FZNT01 KWBC. A TROUGH EXTENDS SW FROM NATE ALONG 32N46W TO
28.5N49W.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 32W/33W SOUTH OF 22N MOVING
WEST 15 KT.  THE WEAK LOW ALONG THE WAVE HAS DISSIPATED.  A
WAVE POSITION IS BASED ON A LOW LEVEL VORTICITY MAXIMUM ALONG
THE WAVE AT 17N. THE WAVE REMAINS IN A DRY/STABLE ENVIRONMENT
WITH NO ASSOCIATED CONVECTION.

TROPICAL WAVE ALONG 58W/59W SOUTH OF 18N IS MOVING WEST 15 KT.
THIS WAVE REMAINS WEAK WITH SCATTERED SHOWERS/TSTMS OCCURRING
ALONG AND WEST OF THE WAVE AXIS. THE CONVECTION ACTIVITY IS
OCCURRING IN AN AREA FROM 13N-20N BETWEEN 56W-67W. SOME OF THE
ACTIVITY OVER THE EAST CARIBBEAN IS NOT DIRECTLY ASSOCIATED WITH
WAVE. THE POSITION OF THE WAVE IS SUPPORTED BY TRACKING THE LOW
CLOUD FEATURES IN THREE DAY SATELLITE LOOPS.

CARIBBEAN SEA TROPICAL WAVE ALONG 72W SOUTH OF 20N IS MOVING
WEST 15 KT. THE WAVE HAS BECOME INCREASING DIFFICULT TO TRACK AS
IT CONTINUES TO INTERACT WITH AN UPPER LEVEL OVER THE ATLC NORTH
OF THE SE BAHAMAS. IT APPEARS THAT MOST OF THE ENERGY WITH THE
WAVE WAS PULLED NORTHWARD INTO THE UPPER LOW WITH LITTLE
ASSOCIATED CONVECTION ACTIVITY REMAINING OVER THE CARIBBEAN.

WESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 87W SOUTH OF 20N
MOVING WEST 15 KT. THIS WAVE IS ALSO INTERACTING WITH A LARGE
UPPER LEVEL NORTHWESTERN CARIBBEAN SEA LOW PRESSURE CENTER.
A BAND OF SHOWERS/THUNDERSTORMS EXTENDING FROM THE YUCATAN
CHANNEL TO JUST N OF THE N YUCATAN COAST NEAR 22N89W ARE
PRIMARILY ASSOCIATED WITH A WEAKENING SURFACE TROUGH OF THE
SOUTHERN GULF OF MEXICO. HOWEVER...ENHANCED SHOWERS/THUNDERSTORM
ACTIVITY MAY OCCUR THIS AFTERNOON OVER PORTIONS OF SE MEXICO AND
CENTRAL AMERICA DUE TO THE WAVE AND UPPER LOW INTERACTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N13W 11N23W 8N36W 8N48W 10N61W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
WITHIN 125 NM OF THE AXIS FROM 50W-58W. ISOLATED TO LOCALLY
WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 75 NM OF THE
AXIS FROM 24W-42W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL LOW CENTERED OVER EXTREME NORTHERN MEXICO NEAR
29N102.5W IS MOVING NNE. THE UPPER LOW WILL BE MOVING ACROSS
THE BORDER INTO WEST TEXAS THIS AFTERNOON. NARROW DOWNSTREAM
RIDGING IS SEEN OVER THE WESTERN GULF WITH AXIS ALONG 22N97W
TO 28N95W. DIFFLUENT FLOW BETWEEN THESE FEATURES AND A WEAK
SURFACE TROUGH ALONG THE COAST OF MEXICO/TEXAS IS SUPPORTING
SCATTERED TO NUMEROUS SHOWERS/TSTMS ALONG AND WITHIN 240 NM
OF THE WESTERN GULF COAST N OF 23N. ANOTHER UPPER LEVEL LOW OVER
THE NW CARIBBEAN IS INTERACTING WITH WEAKENING SURFACE TROUGH
OVER THE SE GULF OF MEXICO TO PRODUCE A BAND OF SCATTERED
SHOWERS/THUNDERSTORMS FROM THE YUCATAN CHANNEL TO JUST N OF
THE YUCATAN COAST NEAR 22N89W. A VERY DRY NELY MID/UPPER FLOW
IS SEEN OVER NORTHERN FLORIDA AND THE NE GULF OF MEXICO. THIS
WILL KEEP MOSTLY SUNNY SKIES ACROSS THESE AREAS WITH LITTLE
IF ANY SHOWER ACTIVITY.

CARIBBEAN...
LARGE UPPER LOW REMAINS OVER THE NORTHWESTERN CARIBBEAN SEA
NEAR 18N86.5W. WIDELY SCATTERED SHOWERS ARE CURRENTLY DEVELOPING
WITHIN 45 NM OF LINE FROM THE GULF OF HONDURAS NE TO NEAR THE
CAYMAN ISLANDS. ADDITIONAL SHOWERS/THUNDERSTORMS WILL LIKELY
DEVELOP OVER LAND AREAS ADJACENT TO THE NW CARIBBEAN AS THE
UPPER LOW INTERACTS WITH A TROPICAL WAVE IN THE AREA. UPPER
LEVEL RIDGE IS BUILDING OVER THE SW CARIBBEAN FROM PANAMA NE TO
JUST SW OF JAMAICA. THIS IS PRODUCING DIFFLUENT FLOW OVER THE SW
CARIBBEAN WHICH HAS LEAD TO AN AREA OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION S OF 12N W OF 79W. THE UPPER LOW
OVER THE ATLC CONTINUES TO MOVE NORTHWARD AWAY FROM THE AREA.
IN ITS WAKE A MODERATE E TO SE MID/UPPER FLOW IS SEEN E OF 70W.

WEST ATLANTIC...
A SMALL UPPER LEVEL ANTICYCLONIC CIRCULATION APPEARS TO BE
CENTERED JUST SW OF OPHELIA AND IS PRODUCING A FAIRLY
FAVORABLE OUTFLOW PATTERN OVER THE CYCLONE. UPPER LEVEL SWLY
WINDS BECOME MUCH STRONGER FARTHER NORTH OFF THE COAST OF NORTH
CAROLINA AND THIS IS SENDING MID/HIGH LEVEL CLOUDS/MOISTURE FROM
OPHELIA WELL NORTHEASTWARD INTO THE ATLC.  AN UPPER LEVEL LOW IS
CENTERED NORTH OF THE SE BAHAMAS NEAR 24N72W. THE LOW IS MOVING
QUICKLY NORTHWARD AND IS BECOMING ELONGATED NORTH TO SOUTH. THE
UPPER LOW IS PRODUCING SCATTERED MODERATE CONVECTION WITHIN 240
NM WEST SEMICIRCLE OF CENTER. THE UPPER LOW IS FORECAST TO
WEAKEN AS IT CONTINUES TO MOVE NE.

EAST/CENTRAL ATLANTIC...
A VERY LARGE AND STRONG UPPER LEVEL HIGH IS CENTERED OVER THE
CENTRAL ATLC WATERS NEAR 26N51W WITH A RIDGE AXIS EXTENDING WNW
TOWARDS OPHELIA. THE HIGH IS PRODUCING BROAD ANTICYCLONIC FLOW
OVER MOST OF THE ENTIRE AREA BETWEEN 35W-65W. THE ONLY EXCEPTION
IS NEAR A WEAK MID/UPPER LEVEL LOW IS LOCATED SE OF THE HIGH
NEAR 16N40W...AND IS MOVING WSW AT 15-20 KT. A STATIONARY UPPER
LEVEL TROUGH EXTENDS FROM NEAR THE CANARY ISLANDS SW ALONG
20N27W TO NEAR THE UPPER LOW MENTIONED ABOVE. THE AREA N OF THE
ITCZ IS COVERED BY DRY/STABLE AIR WHICH IS KEEPING SHOWER AND
THUNDERSTORM ACTIVITY TO A MINIMUM. THE AREA OF SAHARAN DUST
SEEN IN VISIBLE IMAGERY YESTERDAY APPEARS TO BE LESS
CONCENTRATED TODAY.  HOWEVER...SKIES LIKELY REMAIN HAZY OVER THE
EASTERN ATLANTIC FROM 10N-27N E OF 50W.

$$
BROWN

This weather bulletin was brought to you by:
www.nashvilleweather.net