Re: Some models---Bill a little too close for comfort to NE??
Posted by Chucktowner on 8/19/2009, 9:56 am
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
735 AM EDT WED AUG 19 2009

.SYNOPSIS...
THE BERMUDA HIGH WILL REMAIN IN PLACE ALONG THE EASTERN SEABOARD
TODAY...HOWEVER...A CHANGE IN THE WEATHER PATTERN WILL BEGIN ON
THURSDAY. THE BERMUDA HIGH WILL GET PUSHED OUT BY THE PASSAGE OF
BILL WELL OFF THE EAST COAST ON FRIDAY WHILE A COLD FRONT APPROACHES
FROM THE WEST. THE FRONT IS EXPECTED TO MOVE ACROSS THE WESTERN
CAROLINAS ON SATURDAY AND THEN OFF THE EAST COAST BY SUNDAY...
ALLOWING DRIER HIGH PRESSURE TO RIDGE IN FROM THE NORTHWEST EARLY
NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPPER LEVEL RIDGE STUBBORNLY HOLDS ONTO THE CAROLINAS AND GEORGIA
FOR ONE LAST DAY...SPELLING YET ANOTHER HOT AND MUGGY DAY WITH
MAINLY JUST MTN CONVECTION. A BLEND OF THE LATEST GUIDANCE KEEPS
LIKELY POPS ALONG THE TN/NC BORDER...WITH A SHARP GRADIENT TO BARELY
SLIGHT CHANCE SOUTH/EAST OF I-85. THE NCEP 4KM WRF HAS DONE A
REASONABLE JOB THE LAST TWO DAYS...AND IT SHOWS CONVECTION OVER THE
NC MTNS PROPAGATING NEWD...WITH CONVECTION DEVELOPING TO OUR SOUTH
MOVING IN THIS EVENING. SO I ADJUSTED POPS WITH THAT IN MIND. MAX
TEMPS SHOULD BE SIMILAR TO YESTERDAY.

TONIGHT...BOTH THE NAM AND GFS SHOW A SURGE OF DEEP MOISTURE FROM
THE GULF STREAM...MERGING WITH INCREASING TRANSPORT OUT OF THE
EASTERN GULF OF MEXICO...AS HIGH PRESSURE BEGINS TO ERODE ALONG ITS
WESTERN EDGE. THE NAM IS PARTICULARLY BULLISH ON NOCTURNAL
DESTABILIZATION WITH THE MOISTURE AND HAS CONVECTION FIRING ALONG
THE BLUE RIDGE IN SOUTHERLY H85 FLOW. THE 21Z SREF DOESN/T SEEM TO
BE PICKING UP ON THIS. SO I TOOK A BLEND...RESULTING IN A CHC OF
SHWRS/TSTMS ALONG THE BLUE RIDGE. IF THE NAM/GFS ARE RIGHT...PWATS
JUMP TO NEAR 2.00" BY 06Z THURSDAY. SO A HEAVY RAIN THREAT MAY
INCREASE...IF CONVECTION CAN TRAIN OVER THESE UPSLOPE AREAS. WITH
DEWPTS HOVERING AROUND 70 ACRS MUCH OF THE AREA...AND MORE LOW-MID
LEVEL CLOUDINESS...MIN TEMPS WILL BE ABOUT A CATEGORY HIGHER THAN
LAST FEW NIGHTS.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 210 AM WEDNESDAY...AN INTERESTING SHORT RANGE FORECAST FOR THE
END OF THE WEEK. THE UPPER ANTICYCLONE/RIDGE ALONG THE SOUTHEAST
COAST AT THE START OF THE PERIOD GETS SQUINCHED BETWEEN THE
CIRCULATION OF BILL...EXPECTED TO REMAIN WELL OFF THE SE COAST...AND
THE DEEP UPPER TROF DIGGING DOWN FROM THE PLAINS...ACROSS THE MS
VALLEY...TO THE TN VALLEY BY 12Z SUNDAY. THE DESTRUCTION OF THE
UPPER RIDGE AND THE APPROACH OF THE TROF FROM THE WEST SHOULD
IMPROVE OUR PRECIP CHANCES FOR THURSDAY AND FRIDAY. WHAT IS
INTERESTING IS THAT SOME WEAK REFLECTION OF THE REMNANTS OF ANA IS
LIKELY TO MOVE OVER THE SOUTHEAST LATE IN THE WEEK. THE NAM IS MORE
OPTIMISTIC ABOUT BRINGING THIS REMNANT FARTHER N AND W OVER THE
WRN CAROLINAS WHILE THE GFS APPEARS TO KEEP THIS MORE ALONG THE E
COAST. THE PREFERENCE IS FOR SOMETHING CLOSER TO THE GFS...BUT AT
THIS POINT IT APPEARS THAT SOME INFUSION OF RICHER TROPICAL MOISTURE
WILL TAKE PLACE AHEAD OF THE APPROACHING UPPER TROF. FOR THAT
REASON...HAVE RAISED PRECIP CHANCES THROUGHOUT THE ENTIRE PERIOD IN
MOST PLACES. CONVECTION COULD REALLY HAPPEN AT ANY TIME FROM NOON
THURSDAY THROUGH FRIDAY NIGHT AS SOUTH OR SOUTHEAST LOW LEVEL
UPSLOPE FLOW BRINGS THE MOISTURE IN FROM THE ATLANTIC. WENT LIKELY
ACROSS THE MTNS/FOOTHILLS THURSDAY AFTERNOON AND KEPT THE LIKELY
OVERNIGHT ALONG THE BLUE RIDGE AS A RESULT. FRIDAY STILL LOOKS LIKE
THE BEST CHANCE FOR NUMEROUS SHOWERS AND STORMS. THIS COULD EASILY
PERSIST INTO THE FRIDAY NIGHT PERIOD BUT KEPT THE POP IN LINE WITH
GUIDANCE...AND IN THE CHANCE RANGE...FOR NOW. HOPEFULLY...EVERYONE
WILL GET A DECENT RAIN OUT OF THIS SITUATION. AS FOR TEMPS...HAVE
SHADED DOWNWARD FOR HIGHS THURSDAY AND FRIDAY WITH THE INCREASED
CLOUD COVER AND SHOWER COVERAGE.
90
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Some models---Bill a little too close for comfort to NE?? - jack ruby, 8/19/2009, 7:19 am
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