FXUS61 KRNK 140442
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1142 PM EST SAT MAR 13 2010
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO TRACK SLOWLY EAST ALONG THE MID
ATLANTIC COAST THROUGH SUNDAY. HIGH PRESSURE WILL BUILD IN BY
TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
PERSISTENT CONVERGENCE AXIS WRAPPING AROUND UPPER LOW OVER THE
WESTERN CAROLINAS REMAINS ACROSS THE SOUTHERN VA ZONES TONIGHT.
LATEST SHORT TERM MODELS INDICATE THIS AREA TO PERSIST ANOTHER FEW
HOURS BEFORE FADING AS THE COLD POOL ALOFT SLIDES BY AFTER
MIDNIGHT. PRECIP HAS BEEN RATHER LIGHT SO NOT EXPECTING ANY ADDED
FLOODING PROBLEMS BEFORE COVERAGE FADES. ALSO WITH LOSS OF HEATING
APPEARS TSRA CHANCES LESS SO REMOVING MOST THUNDER FOR THE
OVERNIGHT IN THE SE. HOWEVER WITH 00Z RAOBS SHOWING VERY DEEP
MOISTURE IN PLACE WILL NEED TO KEEP AN AXIS OF LIKELY POPS GOING
ACROSS THE SOUTH THRU MIDNIGHT...THEN LIFTING NE ACROSS THE FAR
EASTERN ZONES DURING THE EARLY MORNING HOURS. IN ADDITION WEAK
COLD ADVECTION WILL CONTINUE TO BLEED IN FROM THE NW OVERNIGHT IN
THE WAKE OF THE UPPER SYSTEM WITH A SLIGHTLY DEEPER UPSLOPE
COMPONENT BY MORNING. THIS SUPPORTS A STRIP OF LIKELY POPS OVER
THE NW AS WELL LATE. ANY SNOW SHOWER CHANCES WILL REMAIN ACROSS
THE HIGHEST ELEVATIONS UNTIL WELL AFTER MIDNIGHT WHEN COULD LOWER
TO ABOUT 2500 FEET BY DAYBREAK. THUS DELAYED ANY SNOWFALL FOR A
FEW MORE HOURS ESPCLY GIVEN LACK OF WESTERN PRECIP ATTM UNTIL
BETTER UPSLOPE KICKS IN LATER. LOOKS LIKE MAINLY A COATING
POSSIBLE OUTSIDE THE HIGHEST PEAKS AT THIS POINT. BUMPED DOWN LOWS
A NOTCH IN THE WEST WHILE UPPING SOME IN THE EAST WHERE CLOUDS AND
ONLY WEAK COOL ADVECTION WILL PREVAIL OVERNIGHT.
PREVIOUS DISCUSSION BELOW...
NUMEROUS SHOWERS ONGOING OVER THE FOOTHILLS AND INTO THE LOWER NEW
RIVER VALLEY. HAD REPORTS OF SMALL HAIL FROM CONVECTION IN NC AS
COLDER AIR ALOFT FROM THE UPPER LOW SLIDES IN. DECIDED TO ADD SMALL
HAIL TO THE FORECAST INTO EARLY EVENING AS SUNSHINE HAS HELPED
ENHANCE LAPSE RATES WITH TEMPS IN THE 60S.
FORECAST FOR THUNDER SEEMS REASONABLE AS WELL DOWN EAST. SPEED OF
MOVEMENT HAS CONCERNS FOR EXCESSIVE RAIN. SINCE THE CELLS ARE
FLUCTUATING IN STRENGTH AND NOT AS WIDESPREAD WILL NOT ISSUE ANY
FLASH FLOOD WATCH...BUT WILL MONITOR PROGRESSION. NOT OUT OF THE
QUESTION A FLASH FLOOD WARNING COULD BE ISSUED.
SHOULD SEE SOME DIMINISHING IN COVERAGE OVERNIGHT WITH LOSS OF
HEATING...BUT STRONG DYNAMICS WILL KEEP CHANCES AROUND...WITH BEST
LIFT MOVING ACROSS NC....WITH WINDS BECOMING MORE WEST TO NW ALOFT.
SHOULD ALSO SEE SOME COLDER TEMPS INTO OVERNIGHT WITH SNOWFALL OVER
THE HIGHER MTNS IN NC/SW VA AND SE WV. SNOW AMOUNTS SHOULD BE LESS
THAN INCH DUE TO WET GROUND.
KEPT LOWS TONIGHT UP DUE TO SLOWNESS OF COLDER AIR IN THE LOW LVLS
AND CLOUDINESS/PRECIP LINGERING.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
THE UPPER LOW PRESSURE SYSTEM WILL EXIT THE REGION SUNDAY INTO
MONDAY WITH A NORTHWEST FLOW FOLLOWING IN ITS WAKE. THE UPSLOPE FLOW
WILL ENHANCE THE PRECIPITATION MAINLY IN THE WESTERN MOUNTAINS OF
SOUTHEAST WEST VIRGINIA.
COOLER AIR WILL ADVECT INTO THE AREA BEHIND THE DEPARTING LOW WITH
85H TEMPERATURES RANGING FROM -1C SOUTH TO -3C NORTH.
THEREFORE...SOME SNOW WILL MIX IN WITH THE RAIN OVERNIGHT SUNDAY AND
MONDAY. LOW TEMPERATURES WILL BE AROUND FREEZING BUT EXPECT LITTLE
TO NO SNOW ACCUMULATION. IF ANY ACCUMULATION OCCURRED IT WOULD BE
CONFINED TO THE HIGHER ELEVATIONS AND DO NOT EXPECT MORE THAN A
DUSTING.
A MORE NORTHERLY FLOW WILL DOMINATE THE AREA TUESDAY MORNING WHICH
WILL ALLOW THE UPSLOPE PRECIPITATION TO BE CUT OFF. HAVE REDUCED
TEMPERATURES FOR TUESDAY A COUPLE OF DEGREES AS THE 1000-850
THICKNESSES ARE SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE EXTENDED PERIOD IS CHARACTERIZED BY DRY WEATHER AND NEAR TO
SLIGHTLY ABOVE NORMAL TEMPERATURES. WE WILL REMAIN IN A MEAN TROUGH
THROUGH THE PERIOD...WITH 850MB TEMPERATURES STARTING OUT AROUND 1C
ON TUESDAY AND INCREASING TO 4-5C BY FRIDAY. THIS WILL MEAN WE WILL
SEE INCREASING TEMPERATURES EACH DAY THROUGH FRIDAY.
WITH THE TROUGH OVERHEAD WE WILL HAVE RATHER STEEP LOW LEVEL LAPSE
RATES TUESDAY THROUGH THURSDAY...WHICH COULD ALLOW ISOLATED
AFTERNOON SHOWERS TO DEVELOP. THE BEST CHANCE FOR THIS APPEARS TO BE
ACROSS THE WEST...BUT ANY SHOWERS WILL BE ISOLATED AND THEREFORE
CURRENTLY JUST GOING WITH A DRY FORECAST. THE NEXT CHANCE FOR MORE
WIDESPREAD RAIN DOES NOT APPEAR TO BE UNTIL SUNDAY...WHEN MODELS
SHOW A COLD FRONT MOVING THROUGH.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
BAND OF LIGHT TO MODERATE SHOWERS PERSISTS BETWEEN KLYH/KDAN AND
EXPECT LITTLE CHANGE IN THE NEXT COUPLE OF HOURS BEFORE THE PRECIP
FADES. WITHIN THESE SHOWERS...A PERIOD OF MVFR CONDITIONS LIKELY
WITH A BRIEF REDUCTION IN VSBY POSSIBLE. OTRW EXPECTING MAINLY
VFR OUTSIDE OF SHRA OVER THE EAST OVERNIGHT WHILE THE WEST LINGERS
IN MVFR/OCNL IFR IN LOWER CIGS AND SPOTTY -RA/-DZ BY MORNING. CIGS
WILL LIKELY START TO LOWER MORE AT KBLF AS DEEPER WESTERLY FLOW
DEVELOPS WITH CIGS GOING BELOW 1KFT BY 12Z SUNDAY... AND REMAINING
IN LOW END MVFR IN PATCHY DRIZZLE WHICH SHOULD STICK AROUND THRU
SUNDAY MORNING. MAY SEE SOME BREAKS DUE TO DOWNSLOPE FLOW EAST OF
THE MOUNTAINS SUNDAY AFTERNOON WHILE AREAS WEST OF THE BLUE RIDGE
REMAIN STUCK IN MVFR/IFR CIGS AND PASSING -SHRA.
LOOKS LIKE LOW CLOUDS AND SPOTTY -RA MAY KEEP AT LEAST MVFR
CONDITIONS GOING MAINLY IN THE MTNS INTO MONDAY WITH SOME SLOW
IMPROVEMENT TO VFR BY MID WEEK.
&&
.HYDROLOGY...
AREAL FLOODING CONTINUES OVER PORTIONS OF SOUTHEAST WEST VIRGINIA
AND SOUTHWEST VIRGINIA. WILL MONITOR ANY HEAVIER SHOWERS THAT
COULD CAUSE ADDITIONAL FLOODING FARTHER EAST. AS FAR AS RIVERS
GO...THE FLOOD WARNING IS CANCELLED FOR BUCHANAN ALONG THE JAMES
RIVER. THE NEW RIVER AT RADFORD IS FORECAST TO RISE JUST UNDER
FLOOD STAGE LATE TONIGHT AND JUST ABOVE FLOOD STAGE AT GLEN LYN.
IN ADDITION...MINOR FLOODING IS NOW EXPECTED AT RANDOLPH ON THE
LOWER ROANOKE RIVER BY SUNDAY MORNING.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...REB
NEAR TERM...JH/WP
SHORT TERM...REB
LONG TERM...MC/REB
AVIATION...JH/REB
HYDROLOGY...
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