FXUS61 KRLX 110949
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
445 AM EST THU MAR 11 2010

.SYNOPSIS...
UPPER LEVEL SYSTEM AFFECTS THE REGION THROUGH THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AFTER ANOTHER WARM DAY YESTERDAY AND DEWPOINTS THAT CREPT PAST
40F...EXPECT MORNING COOPS WILL SHOW A PRETTY GOOD DECREASE IN SNOW
COVER ACROSS NORTHERN MTNS. THIS HAS ALREADY RESULTED IN STRONG
RISES IN AREA CREEKS AND STREAMS AS NOTED BY DAY SHIFT. EXPECT SOME
OF THESE ARE ALREADY OUT OF THEIR BANKS NOW. WILL MAKE SOME CALLS
NEXT FEW HRS TO SEE IF SUSPICION IS CONFIRMED. NEEDLESS TO
SAY...AREAL FLOOD WARNING CONTINUES. SEE HYDRO SECTION BELOW. ALSO
NOTICING SOME STEEP CURVES ON SOME OF THE RIVERS...ESPECIALLY ON THE
TYGART...WITH BELINGTON SHOWING IMPRESSIVE RISES ALREADY.

LATEST SAT IMAGERY SHOWING SOME SOME CIRRUS AND MID DECK STEADILY
ADVANCING NORTH AND EAST...WELL AHEAD OF NEXT IMPULSE TO AFFECT THE
AREA. THIS SHOULD PROVIDE FOR SOME CLOUDS THIS MORNING FOR MOST.

MODELS CONT TO SLOW THE ARRIVAL OF AFOREMENTIONED IMPULSE.
CONSIDERING THE AMPLITUDE OF THE H5 RIDGE ACROSS THE EAST AND AMNT
OF DEEP LAYER SUBSIDENCE IN PLACE...THINK MOST OF THE DAYLIGHT HRS
TODAY WILL REMAIN DRY. AS A RESULT...COULD SEE A LITTLE SUNSHINE
FROM TIME TO TIME TODAY. THIS SHOULD ALLOW TEMPS TO CLIMB PAST 70F
MOST AREAS OUTSIDE OF THE MTNS. USED THE WARM MET AS A
BASE...TWEAKING UP TOWARD THE LCL MOS. USING THE LOW LEVEL THICKNESS
VALUES AND TWEAKING DOWN A DEGREE OR TWO TO ACCOUNT FOR CLOUDS
GENERALLY YIELDS 70-72F FOR MUCH OF THE LOWLANDS. EVEN THE HIGHEST
ELEVATIONS IN THE MTNS SHOULD WARM WELL INTO THE 50S COURTESY OF H85
TEMPS OF 9-10C. THIS WILL CONTINUE TO PROMOTE SIGNIFICANT SNOW MELT
IN THE NORTHERN MTNS...FARTHER EXACERBATING THE WATER CONCERNS.

AFOREMENTIONED S/W LOOKS TO ROTATE THRU BETWEEN 22-06Z TONIGHT AS
INDICATED MY MOST OF THE NEAR TERM MODELS. ASSOCIATED BAND OF PCPN
WILL PROBABLY WEAKEN AND BECOME MORE BKN IN NATURE AS IT MOVES
THRU...WITH THE TYPICAL SPLIT OVER THE WV LOWLANDS COURTESY OF
DOWNSLOPING EFFECTS. TRIED TO FINESSE THE POPS USING THAT
THINKING...CONFINING CAT POPS TO NORTHERN PARTS OF SE OH AND MOST OF
THE MTNS. QPF LOOKS TO BE RATHER LIGHT...AROUND A TENTH ACROSS THE
LOWLANDS AND A QUARTER SE OH AND MTNS. COULD BE A FEW STORMS
DEVELOPING AHEAD OF THE MAIN PCPN BAND LATER THIS AFTN...MAINLY
ACROSS NE KY/SW VA/SOUTHWESTERN WV WHERE MARGINAL INSTABILITY
RESIDES. CONT THUNDER FOR THOSE LOCATIONS IN WX GRIDS.

SHOULD SEE A LULL IN THE ACTION LATER TONIGHT AS SIGNIFICANT DRYING
OCCURS IN THE MID LEVELS. LOW LEVEL MOISTURE REMAINS PLENTIFUL
HOWEVER...KEEPING ABUNDANCE OF LOW CLOUDS AROUND. GIVEN WARM MOIST
SOUTHERLY FLOW...WENT A FEW DEGREES ABOVE GUIDANCE FOR LOWS...WITH
MID 50S COMMON OUTSIDE OF THE MTNS.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A CUT OFF UPPER LEVEL LOW WILL SLOWLY DRIFT EASTWARD THROUGH THE
WEEKEND. THIS WILL SEND SEVERAL BANDS OF SHOWERS THROUGH THE AREA.
AS IS TYPICAL WITH A CUT OFF UPPER LOW...MODELS ARE STRUGGLING WITH
TIMING AND PLACEMENT OF THESE BANDS. THEREFORE CONFIDENCE IS LOW IN
THE FORECAST DETAILS.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
WENT ALONG WITH HPC IDEAS FOR THE EXTENDED PERIOD...AGAIN FOLLOWING
THE 00Z ECMWF FAMILY...BLENDED WITH NAEFS. EARLY PORTION OF PERIOD
IS DOMINATED BY CONTINUED INFLUENCE OF LARGE H500 UPPER LOW AND
SLOW-MOVING SURFACE REFLECTION...WHICH EDGES OFF OF THE ATLANTIC
COAST BY MONDAY MORNING. SPOKES OF ENERGY WILL CONTINUE TO ROTATE
AROUND THE SYSTEM. TIMING THESE IS TRICKY AT THIS DISTANCE...SO
KEPT POPS FAIRLY GENERAL OVERALL.

SURFACE LOW SHOULD BE OVER CWA AT START OF PERIOD...WITH BACK EDGE
OF MAIN RAIN SHIELD EXITING TO THE NORTH ALONG WITH ISENTROPIC
LIFT/UPPER DIVERGENCE. THIS WILL BE FOLLOWED BY PASSAGE OF UPPER
LOW ITSELF DURING THE DAY SUNDAY...AND KEPT LIKELY POPS FOR THIS.
THEN HAVE A SLOW DECREASE IN POPS FOR SUNDAY NIGHT/MONDAY AS MAIN
SYSTEM PULLS AWAY BUT VORT LOBES CONTINUE TO ROTATE AROUND. SHOULD
START TO SEE AN UPSLOPE COMPONENT AS WELL WITH LOW LEVEL FLOW
TURNING TO THE NORTHWEST. H850 TEMPS LEAK TO JUST BELOW ZERO WITH
TIME AS WELL...SUGGESTING NIGHTTIME SNOW SHOWERS ARE POSSIBLE IN AT
LEAST THE MOUNTAINS.

AVAILABLE MOISTURE FINALLY STARTS TO THIN BY 12Z TUESDAY...AND
EXPECT ONLY A FEW ISOLATED MOUNTAIN SHOWERS BY THAT TIME. HIGH
PRESSURE THEN SLOWLY STARTS TO NOSE IN FROM THE WEST...WITH PARTLY
CLOUDY SKIES FORECAST FOR TUESDAY NIGHT AND WEDNESDAY.

STAYED CLOSE TO HPC TEMPERATURES OVERALL...WHICH WERE A BLEND OF MEX
AND ENSEMBLE NUMBERS.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
12Z THURSDAY THROUGH 12Z FRIDAY...
EXPECT MAINLY VFR CONDITIONS AREA WIDE TODAY...WITH EXCEPTION OF
SOME MORNING PATCHY PATCHY MVFR FOG. NOCTURNAL ENHANCED LOW LEVEL
JET HAS RESULTED IN WS CONCERNS AS SFC WINDS REMAIN CALM. INSERTED
WS FOR KCRW/KHTS/KPKB UNTIL 13Z...WITH 30KTS 1-2KFT AGL NOTED ON RLX
VAD WIND PROFILE.

CEILINGS WILL GRADUALLY LOWER TODAY AS ANOTHER SHORTWAVE IN
ASSOCIATION WITH LOW PRESSURE OVER THE MIDWEST ROTATES THROUGH THE
REGION. THIS WILL GENERATE ANOTHER ROUND OF RAIN SHOWERS.
PRECIPITATION WILL MOVE FROM SOUTH TO NORTH AND MOVE INTO SW VA/NE
KY BY 22Z...AND INTO CENTRAL WV AND SE OH BY 00Z...EXITING ACROSS
THE NORTH AFTER 06Z. ISOLATED THUNDERSTORMS WILL ALSO BE
POSSIBLE...MAINLY WEST OF A LINE FROM KI43-KHTS AND SOUTH INTO SW
VA. EXPECT MVFR VSBYS AND CIGS IN RAIN SHOWERS.

AFTER 12Z FRIDAY...
OCCASIONAL IFR CONDITIONS AND RAIN SHOWERS FRIDAY NIGHT INTO
SUNDAY.

&&

.HYDROLOGY...
THE MOUNTAIN SNOWPACK HAS BEEN SLOWLY RECEDING DURING RECENT DAYS
BUT IN A CONTROLLED MANNER...AS MELTING SNOW BY DAY HAS BEEN
BALANCED BY BELOW FREEZING TEMPERATURES AT NIGHT. THE MELT WILL
PICK UP SPEED AS TEMPERATURES AT NIGHT STAY ABOVE FREEZING.

STARTING TODAY...THE COMBINATION OF RISING TEMPS AND BREEZY
SOUTHERLY WINDS SHOULD LEAD TO DECENT SNOWMELT OVER NORTHEASTERN
MOUNTAINS WHERE 2 TO 5 INCHES OF LIQUID WATER EQUIVALENT RESIDES.
THEN...RAIN CHANCES WILL BE ON THE INCREASE...WITH THE BEST CHANCES
FRIDAY NIGHT AND SATURDAY AS A LOW PRESSURE SYSTEM CROSSES.

DUE TO THIS INCREASING THREAT...COUNTIES THAT WERE IN THE WATCH
HAVE BEEN UPGRADED TO AN AREAL FLOOD WARNING IN EFFECT THROUGH
SATURDAY NIGHT. THIS IS DUE TO STRONG RISES OF AREA CREEKS AND
STREAMS. SOME OF WHICH ARE EXPECTED TO RISE ABOVE BANKFULL TODAY AND
TONIGHT...RESULTING IN MINOR FLOODING IN LOW LYING AND POOR DRAINAGE
AREAS. THE WARNING WAS ISSUED AT THIS TIME TO MAXIMIZE THE LEAD TIME
AND TO ALLOW RESIDENTS/EMERGENCY MANAGEMENT OFFICIALS TO HAVE PLENTY
OF TIME TO TAKE MEASURES.

THE MAIN STEM RIVERS WILL CONTINUE TO SLOWLY RISE AS THEIR
RESPECTIVE CREEKS CONTRIBUTE THE WATER FROM THE SNOW MELT...COMBINED
WITH EXPECTED RAINFALL OVER THE NEXT FEW DAYS. THE FOLLOWING
RIVERS APPEAR TO BE THE MOST VULNERABLE TO FLOODING FROM THURSDAY
NIGHT ONWARD...TYGART...CHEAT...GREENBRIER... UPPER ELK...AND
UPPER GAULEY.

GETTING INTO NEXT WEEKEND AND BEYOND...WE WILL HAVE TO
MONITOR POTENTIAL IMPACT OF THE SNOWMELT AND RAIN EVENTUALLY
DRAINING INTO THE OHIO RIVER.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...CL
AVIATION...30
HYDROLOGY...30








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