977 FXUS61 KRLX 060302 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1001 PM EST FRI DEC 5 2014 .SYNOPSIS... SERIES OF LOW PRESSURE WAVES CROSS INTO SATURDAY. HIGH PRESSURE SUNDAY. COLD FRONT EARLY NEXT WEEK MAY BE FOLLOWED A BY LONGER PERIOD OF HIGH PRESSURE. && .NEAR TERM /THROUGH SATURDAY/... 945 PM UPDATE. CURRENT FORECAST LOOKS GOOD. PREVIOUS DISCUSSION... NOT MUCH CHANGE IN FORECAST THINKING FROM MIDNIGHT SHIFT. WARM FRONTAL BOUNDARY WILL TRY TO MAKE INROADS THRU CWA THIS EVENING...REORIENTING ITSELF IN A SW TO NE FASHION ACROSS SE OH. AS SUCH...EXPECT MOST OF THE STEADIER RAINS TO SHIFT INTO THOSE LOCATIONS LATER THIS AFTERNOON AND EARLY THIS EVENING. MUCH OF WV AND SW VA SHOULD GET INTO THE WARM SECTOR FOR A TIME THIS EVENING...WITH MORE OF A SCT SHOWERY REGIME TO THE PRECIP. TEMPS WILL STAY UP THRU THE NIGHT WITH CONTINUED WAA AND SE DOWNSLOPING FLOW NEAR THE SURFACE. MOST OF THE HEAVIER QPF WILL BE REALIZED NEAR THE WARM FRONT ACROSS NE KY AND ESPECIALLY SE OH...WHERE UP TO AN INCH OF RAIN IS POSSIBLE OVERNIGHT. THE SURFACE LOW WILL TRACK NE OVERNIGHT...ESSENTIALLY ALONG THE BOUNDARY...THRU SE OH AND N WV. WILL BE WATCHING FOR HEAVY SHOWERS IN THE WARM SECTOR...ALONG A PRETTY STOUT LOW LEVEL JET AND SPEED CONVERGENCE. ALSO OF NOTE IS DECENT THETA E ADVECTION WITH STRONG LIFT INTO THE MID LEVELS. GIVEN ALL OF THIS...EXPECT SOME HEAVIER RAINS TO SWING THRU IN KY AND UP INTO WV LATE TONIGHT. KEPT IDEA OF THUNDER ON NOSE OF THE THETA E RIDGE. ANY CONVECTION WILL ENHANCE RAINFALL RATES AND THIS WILL NEED TO BE MONITORED FOR ANY FLASHY ISSUES. OVERALL THOUGH...LOOKS LIKE MOST OF THE QPF WILL OCCUR IN A 12 HR PERIOD...WITH AN INCH UP TO POSSIBLY 2 INCHES ALONG OH RIVER AND INTO SE OH. AFTER DISCUSSING WITH OUR HYDROLOGIST...ELECTED NOT TO HOIST A FLOOD WATCH AT THIS TIME. OF NOTE RFC AND WPC ARE SHOWING QUITE A BIT LESS IN WAY OF QPF THAN SOME OF THE MORE CONVECTIVE ALLOWING HI RES MODELS. WILL PASS ALONG CONCERNS TO EVENING SHIFT AND KEEP MENTION IN HWO. AS THE SURFACE LOW PASSES TO THE NE...A COLD FRONT WILL SWING THRU DURING THE DAY ON SATURDAY. WHILE MOST OF THE PRECIP WILL EXIT WITH THE FRONT...EXPECT SHOWERS TO ROLL THRU IN THE AFTERNOON WITH PASSAGE OF THE UPPER TROF. ALL IN ALL A DREARY SATURDAY WITH LOW CIGS AND VSBY UNTIL LATER IN THE AFTERNOON. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... NAM SOLUTION IS A FEW HOURS FASTER ON THE LOW PRESSURE WAVE AND ASSOCIATED WIND SHIFT ON SATURDAY COMPARED TO THE GLOBAL GFS/ECWMF. WE MAY HAVE SLOWED DOWN THE FRONT A BIT COMPARED TO THE NAM...BUT NOT MUCH. OF COURSE...WE HAVE THE HOURLY TEMPERATURES PEAKING IN THE MORNING...THEN DROPPING. BUT HOW HIGH TO JUMP THE TEMPERATURE UP...SAY CKB-CKB ON EAST IS HARD TO FIGURE. ANY RAIN MAY HOLD IT DOWN. ON THE OTHER SIDE OF THE FRONT...HAVE TEMPERATURES FALLING SHARPER SATURDAY AFTERNOON IN THE MID OHIO VALLEY THEN OUR PREVIOUS FORECAST. 850 MB MOISTURE CONVERGENCE PEAKS 09Z TO 15Z SATURDAY. A 50 KNOT 850 MB SPEED MAX SWINGS UNDER THE 850 LOW THRU KENTUCKY LATE TONIGHT. THIS WAS ONE REASON WE ADDED THE POSSIBLE OF EMBEDDED THUNDER AHEAD OF THE LOW PRESSURE WAVE. OVERALL...MOST STREAM SHOULD BE ABLE TO HANDLE 1 TO 1.5 INCHES OF RAIN OVER 12 TO 24 HOURS. YET...CONSIDERING THE WETTEST COUNTIES THE PAST WEEK...WE DECIDED TO INTRODUCE A POSSIBLE FLOOD HAZARD IN THE HAZARDOUS WEATHER POTENTIAL FOR LATE TONIGHT INTO SATURDAY...IN CASE HEAVIER RAINS DO DEVELOP WITH THAT FORCING. IN THE WAKE OF THE FRONT...LIGHT RAIN AND DRIZZLE WANES...BUT HELD ONTO IT A BIT LONGER OVER THE SOUTHERN MOUNTAIN COUNTIES...INCLUDING BECKLEY VICINITY. WAS MORE OPTIMISTIC ON SUNSHINE ON SUNDAY...SHOULD BE WELCOMED. TEMPERATURES FORECAST TOUGH SUNDAY NIGHT...AS LOW LEVEL FLOW QUICKLY BECOMES SOUTHEAST AND INCREASES. THINKING AN INVERSION MAY DEVELOP IN THE WESTERN LOWLANDS AND SOME OF THE DEEP MOUNTAIN VALLEYS THOUGH...SO WENT COLDER. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MODELS INDICATE A HIGH PRESSURE MOVING OVER NEW ENGLAND...EXTENDING SOUTHWEST INTO WV SUNDAY NIGHT. ALTHOUGH A COLD AIR MASS WILL BE IN PLACE...THIS PATTERN WOULD BRING EAST TO SOUTHEAST FLOW...CAPABLE TO PRODUCE DOWNSLOPING WARMING ACROSS THE LOWLANDS SUNDAY NIGHT. INCREASED FEW DEGREES FROM HPC GUIDANCE ACCORDINGLY. FOR MONDAY...BUFKIT SOUNDINGS SHOW DRY AIR ALOFT WITH LIMITED MOISTURE IN THE VERY LOW LEVELS WHILE A H500 WEAK SHORTWAVE CROSSES THE AREA. KEPT LOW CHANCE POPS WITH THIS FEATURE...MORE ALONG THE GFS SOLUTION. THE ECMWF BRINGS STRONG COLD AIR ADVECTION FOR THE SAME TIME PERIOD WITH SUCH A WEAK WAVE. BELIEVE ECMWF IS OVERDOING CAA SO PREFERRED THE GFS. BY MONDAY NIGHT FLOW IN THE LOW LEVELS TURN NORTHWEST WITH SOME CAA FROM BOTH MODELS. FIGURE A GOOD SET UP FOR UPSLOPE PCPN. THE GFS BRINGS THE 0C LEVEL AROUND THE NORTHEAST MOUNTAINS WHILE IN THE ECMWF...THE 0C LINE GOES WAY SOUTH OF THE AREA. WENT WITH A BLEND SOLUTION EXPECTING CHANCE POPS WITH FEW SNOW SHOWERS OR MIX PCPN OVER THE MOST FAVORABLE UPSLOPE AREAS...AND RAIN ELSEWHERE. PCPN IS EXPECTED TO TAMPER OFF ON TUESDAY KEEPING CHANCE POPS OVER THE EASTERN MOUNTAINS ESPECIALLY WITH THE UPSLOPE COMPONENT AND DRY WEATHER SPREADING FROM SOUTHEAST OH...EAST. DRY WEATHER EXPECTED THROUGH THE REST OF THE PERIOD AS A HIGH PRESSURE BUILDS IN. WENT CLOSE TO HPC TEMPERATURES THROUGH THE PERIOD. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... 03Z SATURDAY THRU 00Z SUNDAY... A WARM FRONT LIFTS NORTH OF THE AREA TONIGHT...LOW PRESSURE AND COLD FRONT MOVE ACROSS SATURDAY. THIS RESULTS IN WIDESPREAD RAIN AND FOG MAINLY SOUTHEAST OHIO AND NORTHWEST WV EARLY TONIGHT NORTH OF THE WARM FRONT...SPREADING EAST AND SOUTH LATER TONIGHT AND SATURDAY MORNING WITH THE LOW AND COLD FRONT. THUS...THRU 06Z...IFR WILL PREVAIL AT PKB...WITH GENERALLY MVFR CONDITIONS AT HTS...CRW...CKB...EKN...AND FINALLY VFR AT BKW. 06Z-12Z...BECOMING GENERAL IFR IN RAIN AND FOG FROM NORTHWEST TO SOUTHEAST...FIRST AT HTS AND PKB BY 06Z...CRW AND CKB BY 09Z...AND FINALLY AT EKN AND BKW BY 12Z. OCCASIONAL LIFR POSSIBLE ESPECIALLY WEST. AFTER 12Z SATURDAY. THE COLD FRONT SHIFTS EAST ACROSS THE AREA SATURDAY MORNING...REACHING THE OHIO RIVER BY 14Z...CRW TO CKB BY 17Z AND IN THE MOUNTAINS BY 20Z. EXPECT WIDESPREAD IFR/LIFR ACROSS THE AREA EVEN BEHIND THE COLD FRONT WITH RAIN TAPERING OFF. AFTER 18Z...SLOWLY IMPROVING FROM THE WEST TO MVFR WEST OF THE OHIO RIVER IN SCATTERED LIGHT RAIN...REMAINING IFR EAST OF THE OHIO RIVER WITH RAIN CONTINUING.. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE: LOW TO MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR CONDITIONS IN RAIN AND FOG MAY VARY. IF THERE IS ENOUGH DOWNSLOPE COMPONENT TO THE WIND...COULD SEE HIGHER CEILINGS IN TYPICAL DOWNSLOPE IMPACTED LOCATIONS LIKE EKN...CKB AND MAYBE CRW OVERNIGHT. 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. DATE SAT 12/06/14 UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08 CRW CONSISTENCY H L L H L L L L L L L M HTS CONSISTENCY H H H L L L L M M M H H BKW CONSISTENCY L M M M M L L L L L L M EKN CONSISTENCY H H H H L H H H H L L L PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H L L L L L L H AFTER 00Z SUNDAY... IFR POSSIBLE FRIDAY NIGHT INTO THE WEEKEND IN RAIN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/JMV/30/26 NEAR TERM...JMV/30 SHORT TERM...26 LONG TERM...ARJ AVIATION...JMV