313  
FXUS61 KRLX 240136  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
936 PM EDT SUN SEP 23 2018  
   
SYNOPSIS
 
 
FRONTAL BOUNDARY WILL REMAIN NEARLY STATIONARY OVER THE AREA  
THROUGH LATE TONIGHT. THE FRONT LIFTS NORTH AS A WARM FRONT BY  
MONDAY NIGHT. ANOTHER COLD FRONT MOVES IN BY MIDWEEK.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
AS OF 936 PM SUNDAY...  
 
LATEST RADAR MOSAIC SHOWS RAIN SHIELD THAT HAD BEEN IMPACTING  
MUCH OF THE AREA HAS PUSHED NORTHEAST WITH ONLY SOME ISOLATED  
POCKETS OF RAIN ACROSS THE SOUTHWEST COUNTIES.  
 
LATEST HI-RES MODELS INDICATE THIS TREND WILL CONTINUE  
OVERNIGHT WITH THE RAIN INCREASING IN AREAL COVERAGE LATER  
TONIGHT.  
 
WITH THIS IN MIND, HAVE MADE SOME CHANGES TO THE POP AND WX  
GRIDS TO REFLECT THIS THINKING.  
 
AS OF 350 PM SUNDAY...  
RADAR IMAGERY SHOWS AREAS OF STRATIFORM RAIN, LIGHT TO MODERATE  
ACROSS NORTHEAST KY, SOUTHWEST AND CENTRAL WV MOVING EAST  
NORTHEAST PARALLEL TO A NEARLY STATIONARY FRONTAL BOUNDARY. THIS  
FRONT WILL OSCILLATE OVERHEAD THROUGH TONIGHT. RAINFALL AMOUNTS  
SEEM OVERDONE BY ALL MODELS. HALF TO 3/4 OF AN INCH OF RAIN HAS  
BEEN REPORTED IN PERIODS OF 6 HOURS. NOT ENOUGH TO CAUSE  
FLOODING. HOWEVER, ACCOUNTING FOR ADDITIONAL RAINFALL TONIGHT.  
THEREFORE, THE FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH 10Z  
MONDAY.  
 
IN OTHER HAND, MODELS THETA-E FIELDS INDICATE A PACKED GRADIENT  
JUST NORTH OF OUR CWA SEPARATING A JUICY AIRMASS, SOUTH OF THE  
BOUNDARY, FROM A DRIER AIRMASS NORTH OF THE BOUNDARY. MODELS  
SUGGEST THAT H850 WINDS WILL TURN FROM THE SOUTH BY 06Z TONIGHT,  
LIFTING THE STATIONARY FRONT NORTH, AS A WARM FRONT MONDAY  
MORNING. AT THE SAME TIME, H500 CHARTS SHOW A SERIES OF  
VORTICITY MAXIMA RIDING NORTH NORTHEAST, ALONG AND EAST OF THE  
OH RIVER, UNDER PWATS NEAR 2 INCHES, LIMITED BUOYANCY, AND POOR  
DEEP LAYERED SHEAR. THESE PARAMETERS SUGGEST LIMITED CONVECTION  
AND MORE STRATIFORM RAIN WOULD OCCUR.  
 
THERE IS CONSENSUS AMONG THE HRRR, NAM, ECMWF, AND AT SOME  
DEGREE THE RAP13, THAT SUGGESTS A LULL IN PCPN, SPREADING FROM  
EXTREME SOUTHWEST VA, NORTH, ROUGHLY OVER THE EASTERN HALF OF  
THE AREA AFTER 06Z TONIGHT THROUGH MONDAY AFTERNOON. THE REST OF  
MODELS BRING ADDITIONAL AREAS OF RAIN ACROSS THE ENTIRE AREA.  
PREFER THE MODEL CONSENSUS AND CODED HIGHER POPS ACROSS  
SOUTHEAST OH ACCORDINGLY. ADDITIONAL PCPN IS EXPECTED AS THE MID  
LEVEL SHORTWAVES MOVE NORTH ACROSS SOUTHEAST OH MONDAY, AND  
ACROSS THE REST OF THE AREA MONDAY NIGHT. THESE SHORTWAVES COULD  
PRODUCE MODERATE TO HEAVY RAIN, POSING A THREAT FOR FLOODING  
OVER AREAS THAT ARE NEARLY SATURATED. A FLASH FLOOD WATCH  
CONTINUES IN EFFECT FOR NORTHEAST KY, AND PORTIONS OF SOUTHEAST  
OH AND WV THROUGH 10Z OVERNIGHT TONIGHT, BUT IT WILL LIKELY BE  
EXTENDED THROUGH MONDAY NIGHT, OR RE-ISSUE AS A NEW WATCH TO  
DEAL WITH THE UPCOMING RAINFALL.  
 
CLOUDINESS, COOLING RAIN, AND DEWPOINTS IN THE 50S UNDER LIGHT  
NORTHERLY FLOW WILL KEEP TEMPERATURES IN THE COOL SIDE, MORE  
NOTICEABLE NORTHERN SECTIONS. IN FACT, WENT COOLER THAN ALL  
GUIDANCE FOR LOWS TONIGHT, PERHAPS A DEGREE OR TWO ABOVE THEIR  
EXPECTED DEWPOINTS. WENT CLOSER TO THE NBM FOR HIGHS ON MONDAY.  
 

 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
 
 
AS OF 500 PM SUNDAY...  
 
THIS SHOULD BE THE GRAND FINALE TO A WET MONTH ACROSS THE AREA  
AS AN UNSETTLED PERIOD OF WEATHER PERSISTS MUCH OF THE TIME AS  
THE AREA REMAINS IN THE WARM SECTOR. INITIALLY ON MONDAY NIGHT  
A WARM FRONT IS SHOWN BY THE MODELS TO BE LIFTING NORTH ACROSS  
EASTERN OHIO AND WESTERN/CENTRAL PENNSYLVANIA AND A COLD FRONT  
WORKING IN FROM FURTHER BACK IN THE MIDWEST. THE OPERATIONAL  
MODELS CONTINUE TO SHOW SOME RUN TO RUN AND MODEL TO MODEL  
DIFFERENCES IN THE PLACEMENT OF THE HEAVIEST QPF. BASED ON  
SYNOPTICS WHICH SHOW AN EXITING 60 KT+ JET STREAK OVER OHIO AND  
PENNSYLVANIA ALONG AND NORTH OF THE WARM FRONT AND SEVERAL MID-  
LEVEL RIPPLES OF ENERGY NEAR AND JUST NORTH OF THE WARM FRONT  
ONE AREA FOR MODERATE TO HEAVIER RAIN ON MONDAY NIGHT SHOULD BE  
OVER OUT NORTHERN COUNTIES IN WEST VIRGINIA ALONG AND NORTH OF  
THE WARM FRONT WHERE LIFT FROM THE FRONT AND SUPPORT ALOFT IS  
EFFECTIVE AT GENERATING PRECIPITATION. A SECOND AREA SHOULD BE  
OVER OUR NORTHWESTERN COUNTIES IN OHIO, CLOSEST TO THE  
APPROACHING COLD FRONT WHERE AMPLE LIFT AND A HIGH MOISTURE  
CONTENT (PWATS NEAR 1.95 INCHES) ARE SHOWN. FURTHER SOUTH AND  
EAST OF CHARLESTON THESE AREAS MAY NOT SEE MUCH IN THE WAY OF  
SHOWERS OR THUNDERSTORMS MONDAY NIGHT AS THESE LOCATIONS REMAIN  
AWAY FROM THE BEST LIFT AND SUPPORT ALOFT. POPS LEAN TOWARD THE  
ECMWF WHICH SEEMS TO HAVE THE MOST REASONABLE FEEL FOR THE  
LARGER SCALE FEATURES AND PLACEMENT OF HEAVIER QPF. SOME MODELS  
SUCH AS THE 12Z OPERATIONAL GFS LOOKED A LITTLE DRY IN SPOTS IN  
THIS TIME FRAME. THERE WILL BE A THREAT FOR HEAVY RAIN ACROSS  
OUR OHIO AND NORTHERN WEST VIRGINIA COUNTIES IN THE MONDAY NIGHT  
TIME FRAME AND POSSIBLE PONDING OF WATER AND FLOODING WILL NEED  
TO BE WATCHED FOR ALONG WITH AREAS OF DENSE FOG. LOWS SHOULD BE  
ABOUT 10-15 DEGREES ABOVE NORMAL MONDAY NIGHT.  
 
ONCE THE WARM FRONT LIFTS NORTH OF THE AREA ON TUESDAY, THE MAIN  
FOCUS WILL SHIFT TO THE INCOMING COLD FRONT. ALL MODELS,  
INCLUDING THE GFS, NOW HAVE A FASTER TIMING WITH THE FRONT OVER  
MOST OF AREA INITIALLY. FOR TUESDAY, WE SHOULD REMAIN IN THE  
WARM SECTOR WITH REALLY AN ANYTIME CHANCE OF SHOWERS AND  
THUNDERSTORMS WITH CHANCES. THE MAIN THING THAT MAY IMPACT  
TIMING IS WEAKER PIECES OF MID-LEVEL ENERGY MOVING NORTHEAST  
ACROSS THE AREA WITHIN THE WARM SECTOR. SURFACE COMPUTED CAPE  
VALUES ARE SHOWN BY THE GFS TO BE OVER 1500 J/KG WEST OF THE  
OHIO RIVER IN OUR AREA ON TUESDAY AFTERNOON WHICH MAY HELP SOME  
HEALTHIER CONVECTION TO GET GOING. MODELS CONTINUE TO FOCUS SOME  
OF THE HIGHER QPF AMOUNTS OVER OUR NORTHWESTERN COUNTIES IN THIS  
TIME FRAME AS A RESULT. DEPENDING ON HOW MUCH SUN WET GET, HIGHS  
MAY REACH INTO THE LOWER 80S IN WARMER VALLEY LOCATIONS  
ESPECIALLY IN THE SOUTHERN HALF OF THE AREA.  
 
THE COLD FRONT STARTS TO WORKING EAST TUESDAY NIGHT INTO  
WEDNESDAY MOVING FROM INDIANA ACROSS OHIO. PWATS STAY SOLIDLY IN  
THE 1.90-2.10 INCH RAIN IN OUR AREA, WHICH REMAINS AT OR ABOVE  
THE HIGHEST 90 PERCENT THRESHOLD BASED ON SPC SOUNDING  
CLIMATOLOGY. AN 80 KT+ JET STREAK IS PROGGED TO MOVE OVERHEAD  
AT 250 MB COMBINED WITH SOME SUBTLE MID-LEVEL RIPPLES OF ENERGY  
WHICH SHOULD FURTHER AID IN LIFTING OF THE AIR AND GENERATING  
HEAVY RAIN. THIS WILL CONTINUE TO RESULT IN THE THREAT OF  
PONDING OF WATER IN POOR DRAINAGE AREAS AND POSSIBLE FLOODING  
WITH AN EYE NEEDING TO BE KEPT ON AREA RIVERS GIVEN ANTECEDENT  
CONDITIONS (I.E. SATURATED SOILS FROM RECENT RAINS). IN  
ADDITION, GFS SURFACE COMPUTED CAPE VALUES ARE SHOWN TO BE OVER  
1500 J/KG ACROSS THE ENTIRE AREA WITH SOME AREAS OVER 2000 J/KG  
IN WEST VIRGINIA. LIS OF -3 TO -5 ARE SHOWN AS WELL ALONG WITH  
SPEED SHEAR IN FORECAST SOUNDINGS. THUS A THREAT FOR STRONG TO  
SEVERE THUNDERSTORMS WILL ALSO EXIST, WITH THE MAIN HAZARD  
LIKELY DAMAGING WINDS AS SOME SORT OF LINEAR ORGANIZED  
CONVECTION LOOKS FAVORED WITH THE APPROACHING COLD FRONT. LOWS  
TUESDAY NIGHT WILL REMAIN 10-15 DEGREES ABOVE NORMAL AND HIGHS  
ON WEDNESDAY SHOULD BE NEAR TO A FEW DEGREES ABOVE NORMAL.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
AS OF 510 PM SUNDAY...  
 
THE FRONT ITSELF IS EXPECTED TO CROSS THE CENTRAL AND EASTERN  
PORTIONS OF THE AREA WEDNESDAY NIGHT AND EXIT BY THURSDAY  
MORNING. THE THREAT FOR HEAVY RAIN AND STRONG TO SEVERE  
THUNDERSTORMS WILL LINGER INTO THESE AREAS FOR THE FIRST PART  
OF WEDNESDAY NIGHT THEN END WITH THE PASSAGE OF THE COLD FRONT.  
HOWEVER, CLEARING ON THE BACK SIDE OF THE FRONT AWAY FROM THE  
NORTHWESTERN COUNTIES IN OHIO WILL BE SLOW TO COME BY AS THE  
COLD FRONT STARTS TO SLOW DOWN AS IT MOVES TOWARD SOUTHERN  
VIRGINIA AND BECOMES PARALLEL TO THE MID AND UPPER LEVEL FLOW  
ALOFT. THIS COMBINED WITH SOME LINGERING MID-LEVEL ENERGY ALONG  
THE FRONT SHOULD HELP TO KEEP CLOUDS AND THE POSSIBILITY OF  
LIGHTER RAIN SHOWERS AROUND OVER THE ASTERN MOUNTAINS AND  
ADJACENT LOWLANDS INTO THURSDAY AND THURSDAY NIGHT. WE DID  
DECREASE CLOUD COVER SOME AND LOWER POPS OVER THE NORTHWEST  
THIRD OF THE AREA WHERE THE MODEL CONSENSUS IS BETTER FOR THE  
FRONT TO PULL AWAY FROM. 850 MB TEMPS DROP A FEW DEGREES BEHIND  
THE FRONT SO THERE SHOULD BE SOME A SLIGHT DROP IN TEMPERATURES  
BUT NOTHING SIGNIFICANT WITH HIGHS NEAR NORMAL THURSDAY AND LOWS  
STILL 5-8 DEGREES ABOVE NORMAL THURSDAY NIGHT.  
 
ANY 'COOLING' WILL BE VERY SUBTLE WITH THE FLOW ALOFT GOING  
QUASI-ZONAL FOR FRIDAY. MODELS ARE NOW BRINGING ANOTHER BATCH OF  
ENERGY INTO THE GREAT LAKES BY NEXT WEEKEND WHICH FOR NOW SHOULD  
STAY FAR ENOUGH NORTH OF THE AREA TO KEEP THINGS DRY. HOWEVER,  
MID AND HIGH LEVEL CLOUDS MAY MAKE A RETURN ESPECIALLY BY LATER  
SATURDAY INTO SUNDAY. OTHERWISE EXPECT LOWS ABOUT 3-5 DEGREES  
ABOVE NORMAL ON SATURDAY AND 5-7 DEGREES ABOVE NORMAL ON SUNDAY  
WITH HIGHS NEAR TO A FEW DEGREES ABOVE NORMAL SATURDAY AND  
NEARING 5 DEGREES ABOVE NORMAL SUNDAY. THE NBM MODEL WAS MAINLY  
FOLLOWED FOR TEMPERATURES.  
 

 
   
AVIATION /02Z MONDAY THROUGH FRIDAY/
 
 
AS OF 746 PM SUNDAY...  
 
RADAR IMAGERY AND SFC OBS CONTINUE TO SHOW IFR/LIFR CONDITIONS  
UNDER LIGHT TO MODERATE RAIN EXTENDING FROM NORTHEAST KY,  
NORTHEAST INTO OUR NORTHEAST MOUNTAINS. OUTSIDE OF THE  
PRECIPITATION, VFR/MVFR CONDITIONS PREVAILED.  
 
THE AREA OF RAIN IS PUSHING SLOWLY EAST WHICH SHOULD BRIEFLY  
ALLOW AREAS TO THE WEST TO IMPROVE. HOWEVER, IFR CONDITIONS MAY  
DEVELOP AS LOW CLOUDS AND/OR FOG DEVELOP.  
 
MODELS SUGGEST THE LULL IN PCPN SPREADING FROM WEST TO EAST  
WILL CONTINUE. HOWEVER, ABUNDANT LOW LEVEL MOISTURE, CLOUDINESS  
AND FORCING ALOFT WILL BRING AREAS OF RAIN AND ASSOCIATED IFR  
CONDITIONS, ONCE AGAIN SPREADING FROM WEST TO EAST BY 12Z.  
 
FRONT WILL MOVE NORTH OF THE AREA LATER ON MONDAY, KEEPING HIGH  
PROBABILITIES FOR RAIN AND IFR CONDITIONS ACROSS SOUTHEAST OH  
AND NORTHERN WV.  
 
EXPECTING WIDESPREAD IFR/LIFR IN POST RAIN FOG AND LOW STRATUS  
ON MONDAY. LIGHT NORTHEASTERLY WINDS THROUGH THE PERIOD.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS  
 
ALTERNATE SCENARIOS: TIMING OF PCPN AND CHANGE OF CONDITIONS  
TONIGHT AND MONDAY MAY VARY FROM FORECAST. MORE LIFR AND VLIFR  
CONDITIONS ARE POSSIBLE LATE TONIGHT THAN CURRENTLY FORECAST.  
 
AFTER 00Z TUESDAY...IFR AT TIMES IN SHOWERS AND THUNDERSTORMS  
AND POST RAIN STRATUS AND FOG THROUGH AT LEAST MID WEEK.  
 

 
 

 
   
RLX WATCHES/WARNINGS/ADVISORIES
 
 
WV...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR WVZ005>008-  
013>020-024>032-034-039-040-515>526.  
OH...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OHZ086-087.  
KY...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR KYZ101>103-105.  
VA...NONE.  
 

 
 

 
SYNOPSIS...ARJ  
NEAR TERM...JSH/ARJ  
SHORT TERM...STACHELSKI  
LONG TERM...STACHELSKI  
AVIATION...JSH  
 
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