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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 061844
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
142 PM EST FRI DEC 6 2013

.SYNOPSIS...
SLOW MOVING COLD FRONT CONTINUES SOUTHEAST WITH ABUNDANT
PRECIPITATION THROUGH TONIGHT. BRIEF HIGH PRESSURE SATURDAY.
ANOTHER WET SYSTEM SUNDAY AND MONDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
-- Changed Discussion --
MODELS CONTINUE TO ADVERTISE A COUPLE MORE WAVES MOVING UP THE COLD
FRONT AS IT SLOWLY SAGS SOUTHEAST. ACTUAL COLD FRONT IS SE OF
CWA...BUT BELOW 0C AIR REMAINS MAINLY NW OF CWA...WITH SLIGHT WARM
NOSE ALOFT STILL IN PLACE AS WELL. RAIN/WINTRY MIX LINE APPEARS TO
BE NUDGING INTO NW PERRY COUNTY AS OF 18Z. TEMPERATURES IN THE LOWER
ATMOSPHERE WILL REMAIN FAIRLY STEADY...OR VERY SLOWLY COOL THIS
AFTERNOON UNTIL NEXT WAVE PASSES AND COOLER AIR CAN BEGIN TO FILTER
IN. THAT WAVE LOOKS TO BE IN CENTRAL KY RIGHT NOW. HAVE ONE MORE
WAVE STILL PROGGED TO MOVE NW AS WELL THIS EVENING...AND THEN PRECIP
INTENSITIES SHOULD BEGIN TO DECREASE FROM NORTHWEST TO SOUTHEAST
EARLY SATURDAY MORNING. USED A BLEND OF NAM/RAP FOR WARM NOSE INTO
TONIGHT...THEN TRANSITIONED TO NAM/GFS BLEND...AND USED THIS TO
DEVELOP P-TYPE TRANSITION ZONE AND SNOW ACCUMULATIONS. THIS PROCESS
COOLED THINGS A BIT FASTER THAN PREVIOUS FORECAST...SO HAVE WINTRY
PRECIP MIXING IN JUST A BIT FASTER. DUE TO THIS...ADDED JACKSON
COUNTY OHIO TO WINTER WEATHER ADVISORY FOR SNOW/SLEET ACCUMULATIONS.
COUNTY AVERAGE SNOW ACCUMULATION ACROSS PERRY COUNTY REMAINS
MARGINAL FOR WARNING CRITERIA...BUT STILL EXPECT A DOSE OF HEAVY
SNOW THIS AFTERNOON INTO TONIGHT. HEAVIEST ACCUMULATIONS SHOULD BE
IN THE NW HALF OF THE COUNTY. COULD GET A VERY BRIEF PERIOD OF
FREEZING RAIN ACROSS LOWLANDS AS COLDER TEMPS DROP SE THROUGH THE
NIGHT...HOWEVER WITH WARM/WET GROUND THE ONLY ICE ACCUMULATIONS
SHOULD BE VERY LIGHT AND ONLY ON ELEVATED SURFACES -- FOR EXAMPLE
TOPS OF CARS.

USED NON-DIURNAL TEMPERATURES TONIGHT AND TOMORROW...BY BLENDING
MAV/MET TEMPS TONIGHT AND MAV/CONSALL TEMPS FOR HIGHS. THIS KEEPS
TEMPS DROPPING AT HIGHER ELEVATIONS THROUGH THE DAY TOMORROW. LOWER
ELEVATIONS MAY GET A LITTLE DIURNAL RISE BUT ONLY A DEGREE OR TWO.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
ONLY MINOR DIFFERENCES WITH THE LARGE SCALE FEATURES IN RUN TO RUN
COMPARISONS OF VARIOUS SHORT TERM MODEL OUTPUT. NOT MUCH CHANGE WITH
THE OVERALL PREVIOUS FORECAST FOR SATURDAY. SFC FRONT AND AXIS OF
DEEP LAYER MOISTURE CONTINUES TO PUSH OFF TO THE SOUTHEAST DURING
THE DAY SATURDAY. PRECIP CHANCES WILL WIND DOWN FROM WEST TO EAST
DURING THE 12Z-18Z TIME FRAME MAINLY EAST OF THE OHIO RIVER. DRYING
IN THE MID-LEVELS DURING THIS TIME FRAME SUGGESTS THE POTENTIAL FOR
THE END OF PRECIP TO POTENTIALLY BE SLEET/FREEZING RAIN. THIS BEARS
WATCHING OF COURSE BUT AMOUNTS SHOULD REMAIN ON THE LIGHT SIDE.
CLOUDS MAY BE SLOW TO BREAK EAST OF THE OHIO AS USUAL WITH CONTINUED
COLD ADVECTION BUT EVEN HERE SHOULD SEE SOME LATE DAY PARTLY CLOUDY
SKIES. MEANWHILE...SE OHIO ZONES SHOULD SEE BREAKS IN THE CLOUDS BY
MID-MORNING SAT.

THINGS BEGIN TO CHANGE RAPIDLY OVERNIGHT SATURDAY NIGHT AS SFC HIGH
PRESSURE PUSHES OFF TO OUR NORTHEAST AND THE NEXT WAVE OF LOW
PRESSURE RIDES NORTHEAST ALONG THE FRONT TO OUR SOUTHEAST. TEMPS
SHOULD FALL DURING THE EVENING HOURS SAT NIGHT INTO THE LOW/MID 20S
MOST LOWLAND LOCATIONS BEFORE LEVELING OFF AS DENSE CLOUD COVER
MOVES OVERHEAD AND WIND DIRECTION QUICKLY VEERS FROM NORTH AT 00Z
SUN TO THE EAST BY 12Z SUN. MEANWHILE...DEEP LAYER MOISTURE PROGGED
TO ARRIVE AGAIN FROM SOUTH TO NORTH BTWN 12Z AND 18Z SUN...AND AS
SUCH HAVE BUMPED UP POPS TO CATEGORICAL PRETTY MUCH EVERYWHERE
EXCEPT THE NORTHWEST ZONES BY 18Z SUN. PRECIP TYPE AT THIS POINT
APPEARS TO TRANSITION FROM SNOW TO SLEET/FZRA TO FINALLY RAIN BY
AROUND THE 18Z-19Z TIME FRAME FOR THE CRW-HTS CORRIDOR SOUTH INTO
THE COALFIELDS...AND FOR THE PKB-CKB AREA BY AROUND 21Z. CODED UP A
QUICK HALF INCH TO AN INCH OF SNOW FOR MUCH OF THE LOWLANDS EARLY
SUNDAY MORNING PRIOR TO THE CHANGEOVER. THE NORTHWEST ZONES MAY
REMAIN IN AN ALL SNOW OR WINTRY MIX ALL DAY...WHERE THESE LOCATIONS
MAY SEE A BIT MORE TOTAL SNOW BY LATE SUNDAY...PERHAPS AROUND
1.0-1.5 INCHES. ALSO...THERE CONTINUES TO BE A GREATER CONCERN FOR A
FAIRLY PROLONGED FREEZING RAIN EVENT FOR THE EASTERN MOUNTAINS PER
LATEST GUIDANCE FROM SUN MID AFTERNOON INTO SUN EVENING AND INTO
EARLY OVERNIGHT MONDAY. AS SUNDAY AFTERNOON IS STILL FIVE PERIODS
OUT...OPTED TO NOT ISSUE ANY ICE HIGHLIGHTS DUE TO ONGOING
HIGHLIGHTS...AS WELL AS TO ALLOW THE DAY SHIFT TO TAKE ANOTHER LOOK
AT THE EVENT.

TEMPS ON SUNDAY NIGHT WILL CONTINUE TO SLOWLY RISE DURING THE
OVERNIGHT HOURS AS MOISTURE CONTINUES TO FLOW INTO THE AREA...HAVE
CONTINUED THE NON-DIURNAL TEMP CURVE WHICH THE PREVIOUS SHIFT HAD A
GOOD HANDLE ON. A GOOD CHANCE OF PRECIP WILL CONTINUE DURING THE
OVERNIGHT HOURS...BUT PRECIP BY EARLY MONDAY MORNING SHOULD BE ALL
RAIN EXCEPT PERHAPS THE FAR NORTHERN REACHES OF PERRY COUNTY OH AND
A FEW SHELTERED DEEP VALLEYS OF THE EASTERN MOUNTAINS. WILL ALSO
NEED TO CONTINUE TO MONITOR WATER AS WELL. WITH PRECIP RECEIVED FROM
THIS CURRENT ROUND...IT MAY NOT TAKE TOO TERRIBLY MUCH FOR FLOODING
WITH SUNDAY AND SUNDAY NIGHT/S ROUND.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
REASONABLE MODEL AGREEMENT WITH THE LAST IN A SERIES OF LOW PRESSURE
SYSTEMS TO AFFECT OUR AREA THIS PERIOD. LOW CENTER LIFTS NORTH JUST
TO THE WEST OF OUR AREA MONDAY...BEFORE SWEEPING A COLD FRONT THRU
MONDAY NIGHT AND ENDING PRECIPITATION. AHEAD OF THE LOW...STUBBORN
COLD AIR DAMMING IS NOTED ON THE MODELS ON EAST FACING SLOPES OF THE
WEST VIRGINIAN MOUNTAINS...WITH A GOOD WARM SURGE WEST OF THE
MOUNTAINS SUNDAY NIGHT AND MONDAY. THUS...EXPECT A PERIOD OF
FREEZING RAIN ON EAST FACING SLOPES BEFORE CHANGING TO ALL RAIN
MONDAY MORNING. ELSEWHERE...RAIN. AMOUNT OF QPF LOOKS TO BE POSSIBLY
HEAVY...AND WILL HAVE TO WATCH WATER PROBLEMS CLOSELY IN ADDITION TO
CURRENT RAINFALL EVENTS. WITH STRONG ANTICYCLONIC CURVATURE IN THE
SURFACE HIGH BUILDING IN BEHIND THE SYSTEM MONDAY NIGHT...POST
FRONTAL SNOW SHOWERS DO NOT LOOK AS POTENT AND LONG LIVED AS ONE
WOULD THINK IN THE COLD ADVECTION UPSLOPE FLOW. THUS...MINOR SNOW
ACCUMULATIONS EXPECTED. HIGH PRESSURE BUILDS IN TUESDAY THRU
THURSDAY WITH DRY AND COLD WEATHER.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
GENERAL RULE THROUGH THE NIGHT WILL BE IFR CEILINGS WITH MVFR TO
IFR VISIBILITIES AS LARGE STORM SYSTEM CONTINUES TO IMPACT THE
REGION. SHOULD START TO SEE CEILINGS IMPROVE EARLY SATURDAY
MORNING ACROSS SE OHIO...THEN IMPROVEMENT TO MVFR AT TAF SITES
DURING THE DAY SATURDAY AS THE SYSTEM PULLS AWAY. THIS AFTERNOON
PRECIP SHOULD BE MAINLY RAIN BUT THEN PRECIPITATION TYPE BECOMES A
TOUGH CALL AT TIME AS COLD AIR BEGINS TO FILTER IN FROM THE WEST.
WESTERN TAF SITES WILL BE THE FIRST TO CHANGE...GOING FROM RAIN TO
SLEET TO SNOW OVER A SEVERAL HOUR TIME PERIOD. CAN NOT RULE OUT A
VERY BRIEF PERIOD OF FREEZING RAIN...HOWEVER PAVEMENT WITH BE WARM
AND WET SO SHOULD NOT GET ANY ICE ACCUMULATION EXCEPT POSSIBLY ON
ELEVATED SURFACES. LIGHT SNOW SHOWERS WILL DECREASE FROM WEST TO
EAST SATURDAY MORNING.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING OF CATEGORICAL AND PRECIP CHANGES MAY VARY.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    L
BKW CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M
EKN CONSISTENCY  M    H    H    H    H    H    H    M    M    M    M    M
PKB CONSISTENCY  M    H    H    H    H    H    H    H    H    M    M    L
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M

AFTER 18Z SATURDAY...
IFR POSSIBLE SUNDAY AND MONDAY.
-- End Changed Discussion --

&&

.HYDROLOGY...
SIGNIFICANT RISES ARE OCCURRING/EXPECTED ON RIVERS IN RESPONSE TO
ONGOING...PROLONGED RAIN WHICH IS EXPECTED TO LAST THROUGH TODAY.
RIVERS THAT ARE ESPECIALLY VULNERABLE INCLUDE...BUT ARE NOT
LIMITED TO -- THE LITTLE SANDY INCLUDING GRAYSON...THE WEST FORK
INCLUDING CLARKSBURG...THE LITTLE
KANAWHA...MUD...POCATALICO...TYGART VALLEY...AND SYMMES CREEK.
RISES ARE ALSO EXPECTED ON SMALL CREEKS AND STREAMS THAT DRAIN
INTO THESE LARGER...MAIN STEM WATERWAYS.

ANOTHER WET SYSTEM WILL EFFECT THE REGION ON SUNDAY AND MONDAY. WITH
THE RIVERS ALREADY RUNNING HIGH FROM THE CURRENT EVENT...THE
THREAT OF RIVER FLOODING REMAINS...AND EVEN INCREASES.

&&

.EQUIPMENT...
-- Changed Discussion --
REPAIRS CONTINUE AT PARKERSBURG ASOS...AND AUTOMATED OBSERVATIONS
MAY BE UNAVAILABLE AT TIMES.
-- End Changed Discussion --

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLOOD WATCH THROUGH SATURDAY MORNING FOR WVZ005>011-013>020-
     024>032-037>040-047.
OH...FLOOD WATCH THROUGH SATURDAY MORNING FOR OHZ067-075-076-
     083>087.
     WINTER WEATHER ADVISORY UNTIL 1 AM EST SATURDAY FOR OHZ067-075-
     076-083-084.
     WINTER STORM WARNING UNTIL 1 AM EST SATURDAY FOR OHZ066.
KY...FLOOD WATCH THROUGH SATURDAY MORNING FOR KYZ101>103-105.
VA...NONE.

&&

$$
SYNOPSIS...JMV/MZ/SL
NEAR TERM...MZ
SHORT TERM...JM
LONG TERM...JMV
AVIATION...MZ
HYDROLOGY...MZ
EQUIPMENT...MZ