Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 131745
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
145 PM EDT SUN APR 13 2014

.SYNOPSIS...
SOUTHERLY FLOW INCREASES THIS AFTERNOON WITH WARM SUMMER LIKE
TEMPERATURES. STRONG FRONT MONDAY NIGHT. HIGH PRESSURE REST OF THE
WORK WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
SENT A QUICK UPDATE TO INCREASE COVERAGE OF LIGHT SHOWERS ACROSS
PORTIONS OF SOUTHEAST OHIO DURING THE MORNING HOURS PER LATEST
RADAR IMAGES. ALSO INCREASE SKY THERE FOR CONSISTENCY. REST OF
FORECAST REMAIN REPRESENTATIVE.

PREVIOUS DISCUSSION BELOW...
6 AM UPDATE. WIDELY SCATTERED NOCTURNAL MID LEVEL SHOWERS HAVE
FORMED OVER CENTRAL AND SOUTHWESTERN OHIO...ON THE NOSE OF AN 850
MB SOUTHWESTERLY JET. THESE ARE TRACKING NORTHEAST...MAINLY
NORTHWEST OF PERRY...VINTON AND MORGAN COUNTIES. WILL INCLUDE JUST
A SMALL CHANCE OF A SHOWER THERE EARLY THIS MORNING...BEFORE THEY
DISSIPATE SHORTLY AFTER DAWN. OTHERWISE...CLOUDS OVER SOUTHEAST
OHIO WILL DECREASE TO JUST MAINLY THIN CIRRUS DURING THE DAY.
REMAINDER OF AREA NO CHANGE.

PREVIOUS DISCUSSION...
HIGH PRESSURE OFF THE EAST COAST WILL STILL BE STRONG ENOUGH TO
DOMINATE OUR WEATHER THIS PERIOD...ALTHOUGH CLOUDS INCREASE FROM THE
WEST LATE TONIGHT AHEAD OF AN APPROACHING COLD FRONT. THE BIG ISSUE
TODAY WILL BE FIRE DANGER. WITH INCREASING PRESSURE GRADIENT BETWEEN
THE HIGH AND APPROACHING COLD FRONT...SOUTHERLY WINDS WILL BECOME
GUSTY UP TO NEAR 30 MPH IN PLACES LATER THIS MORNING AND AFTERNOON.
PLENTY OF SUNSHINE AND SOUTHERLY WINDS WILL DRIVE TEMPERATURES WELL
INTO 80S THIS AFTERNOON...ABOVE MOST GUIDANCE WITH A RECENT HISTORY
OF COLD BIAS. LOW LEVEL MOISTURE WILL BE SLOW TO INCREASE
TODAY...SO THAT THE COMBINATION OF THESE FACTORS AND DRYING FUELS
PRESENT AN ENHANCED FIRE THREAT. THE RAP MODEL IN THE HI RES SUITE
OF MODELS SHOW THIS MOST CLEARLY WITH SOME DRIER AIR MIXING DOWN
DURING THE DAY. WE FORECAST RELATIVE HUMIDITIES TO DROP INTO THE 25
TO 30 PERCENT RANGE THIS AFTERNOON...NOT QUITE ENOUGH FOR A RED FLAG
WARNING. HOWEVER...ENOUGH CONCERN TO ISSUE A SPECIAL WEATHER
STATEMENT FOR AN ENHANCED FIRE THREAT TODAY. WILL MONITOR RELATIVE
HUMIDITIES CLOSELY FOR ANY CHANGES. PLENTY OF SUNSHINE TODAY THRU
THIN HIGH CLOUDS.

FOR TONIGHT...SOUTH WINDS DO SUBSIDE WITH LOSS OF HEATING...WHILE
CLOUDS DO INCREASE FROM THE WEST LATER TONIGHT AHEAD OF THE
APPROACHING COLD FRONT. HAVE TO GO ABOVE GUIDANCE AGAIN
TONIGHT...WITH A SOUTHERLY BREEZE PREVAILING AND CLOUDS INCREASING.
LOOK FOR LOWS MOSTLY IN THE 60S.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
LOW LEVEL JET AHEAD OF THE COLD FRONT NOW NOT BEING DEPICTED AS
STRONG COMPARED TO THE MODEL RUNS LAST NIGHT. NEVERTHELESS...COLD
FRONT IS POTENT AND WILL EXPECT A LINE OF CONVECTION CAPABLE OF
STRONG WINDS DESPITE THE WEAKENED LOW LEVEL DYNAMICS. INSTABILITY
STILL LESS THAN IMPRESSIVE WITH DEWPOINTS IN THE LOW 50S. QUESTIONS
ARISE IN THE POPS AHEAD OF THIS EXPECTED LINE ON MONDAY IN THE WARM
SECTOR. CANNOT LEAVE POPS OUT...BUT IN EFFORTS TO GET MORE
DETERMINISTIC WITH THE TIMING OF CONVECTION CHANCES...HAVE TRIMMED
THE FRONT END BY A FEW HOURS AND WAIT UNTIL MID AFTERNOON BEFORE
INTRODUCING THE HIGHER POPS. DUE TO THE NORTHWARD TRACK OF THE MAIN
CENTER OF LOW PRESSURE WITH THIS FRONTAL SYSTEM...IT WILL TAKE SOME
TIME TO CLEAR THE FRONTOGENETIC FORCING OUT OF THE
CWA...NECESSITATING THE CHANCES FOR POPS INTO TUESDAY.

A VERY COLD AIRMASS FOLLOWS BEHIND THE SYSTEM WITH THICKNESSES
DROPPING TO AROUND 520DKM OVER THE NORTHWEST ZONES AND 850MB
TEMPERATURES IN THE -10-12C RANGE...DEPENDING ON THE MODEL.
REGARDLESS...IT WILL BE COLD...AND WILL LIKELY END UP BELOW FREEZING
TUESDAY NIGHT WITH A SURFACE DOME OF HIGH PRESSURE OVER THE MIDDLE
OHIO VALLEY. LIKELY WILL HAVE A SHARP DISCREPANCY IN BETWEEN THE
HILL TOPS AND THE VALLEYS.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
GENERALLY QUIET REST OF THE WORK WEEK WX WISE. CONTINUES TO LOOK
LIKE QUITE A CHILLY NIGHT TUESDAY WITH MANY PLACES DIPPING WELL
BELOW FREEZING. SOME MODERATION ON WEDNESDAY BUT STILL BELOW
NORMAL FOR THIS TIME OF YEAR. THE MORE ROBUST WARM UP OCCURS
THURSDAY AND FRIDAY AS UPPER HEIGHTS BUILD AND WAA COMMENCES ON
DEVELOPING SW FLOW ALOFT. SOME DIFFERENCES AMONGST THE MODELS
BECOME EVIDENT FOR SATURDAY REGARDING INBOUND TROF AND ASSOCIATED
COLD FRONT. WILL PLAY IT CLOSE TO WPC AND GO WITH SOME CHANCE POPS
AT THIS DISTANCE.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
SATELLITE IMAGES SHOW HIGH LEVEL CIRRUS CROSSING THE AREA. SFC
OBSERVATIONS INDICATED THAT THE STRONG SOUTHWEST WINDS ARE MIXING
DOWN TO THE SURFACE AS EXPECTED. RADAR VAD WINDS SHOW SOUTHWEST
WINDS A LITTLE STRONGER ABOUT 2000 FEET. THIS COULD PRODUCE
MOUNTAIN TURBULENCE MAINLY AFFECTING BKW AND EKN THIS AFTERNOON
THROUGH TONIGHT.

MODELS SHOW INCREASING SOUTHWEST FLOW OVERNIGHT. UNDER WAA AND
ISENTROPIC UPGLIDE...THE LOWER ATMOSPHERE COULD DECOUPLE PRODUCING
LIGHT VARIABLE WINDS AT THE SURFACE...BUT 20 TO 30 KNOTS WINDS
ALOFT. THIS COULD PRODUCE LLWS FOR AREAS THAT DECOUPLE OVERNIGHT.

WINDS WILL INCREASE ONCE AGAIN MONDAY WITH DIURNAL MIXING GUSTY UP
TO 30 KNOTS ACCOUNTING FOR BUFKIT SOUNDING MOMENTUM TRANSFER.
MIXING COULD BE BEST IF A DIURNAL DECK CU DEVELOPS PROVIDING AREAS
OF DIFFERENTIAL HEATING. EXPECT STRONG WINDS OVER HIGHER
ELEVATIONS.

THE INCREASE IN WINDS IS DUE TO THE APPROACHING STRONG COLD FRONT.
HOWEVER...THE FRONT AND THE CONVECTION ASSOCIATED WITH IT COULD
ENTER SOUTHEAST OH BY THE END OF THE PERIOD OR BY 18Z MONDAY.

MVFR/IFR CEILINGS COULD DEVELOP OVER BKW AND OTHER MOUNTAINS
VALLEYS UNDER SURFACE SOUTHEAST FLOW. OTHERWISE...WIDESPREAD IFR
CONDITIONS EXPECTED THROUGH THE PERIOD, EXCEPT FOR CEILINGS AROUND
8000 FEET AND A BRIEF SHOWER OVER PARTS

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

FORECAST CONFIDENCE: HIGH.

ALTERNATE SCENARIOS: LLWS COULD BE INCLUDED IN TAF LATER IF
ATMOSPHERE DECOUPLES...MAINLY AT EKN AND CRW.

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
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
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    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR CONDITIONS EXPECTED LATE MONDAY INTO MONDAY NIGHT UNDER
MODERATE RAIN SHOWERS.

&&

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

&&

$$
SYNOPSIS...JMV/26
NEAR TERM...ARJ/JMV
SHORT TERM...ARJ/26
LONG TERM...30
AVIATION...ARJ








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