000 FXUS61 KRLX 181019 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 520 AM EST MON DEC 18 2006 .AVIATION /12Z TO 12Z/... COLD FRONT CONTS TO APPCH FM THE NW. LTL CHANGE IN TIMING OF THE FRONT FM PVS AVN DISCUSSION /REACHING OH RVR ARND 15Z/. VFR QUICKLY BCMS MVFR ONCE FRONT ARRIVES. MVFR RW ARE LKLY AT EKN THIS AFTN WITH FROPA...WHILE REMAINDER OF THE TERMINALS PROB TOO LOW FOR INCLUSION. NRLY WINDS COMMENCE AT BKW ARND 6Z MON...WHICH COULD DROP CIGS TO IFR...BUT FOR THE TIME LEFT IT JUST ABV /012/. DZ WL BE SPOTTY IN THE MTNS TNGT. MVFR CIGS LIFT AT PKB AND CKB TWRD THE TAIL END OF THE FCST AS DRIER AIR ARRIVES...OTRW OVC012-025 RULE. && .PREV DISCUSSION... /ISSUED 344 AM EST MON DEC 18 2006/ SHORT TERM /TODAY AND TONIGHT/... BAROCLINIC ZN APPROACHING I-70 IN OH...WHILE RW CONT TO TRAIN ACR NRN OH WHERE DEEPER MSTR EXISTS. A WARM OVRNGT WITH MID AND UPR 50S COMMON THRU THE LLNDS AND 40S IN THE MTNS. 0Z NCEP CHAIN AGREE ON ANAFRONT TIMING /SEE AVN XCTN BLW FOR MORE SPECIFIC/...THE BIG QSTN IS AREAL CVRG OF RW...IF ANY. SREF MEAN KEEPS ALL QPF OVR WV ALBEIT LESS THAN A NICKEL. GFS SLOSHES A FEW HUNDREDTHS AREA WIDE AND THE NAM-WRF FALLS IN LINE WITH THE SREF. LCL HI-RES MDLS ARE NOT KEEN ON PCPN EITHER PER WK DYNAMICS. OPTED TO LWR POPS A SMIDGE TO SCHC OUTSIDE THE NRN MTNS. UNDER NW WINDS AND ABUNDANT LLVL RH...EKN SHOULD SQUEEZE A FEW HUNDREDTHS OUT. AS BAROCLINIC ZN SLOWLY MEANDERS S THRU THE COAL FLDS TNGT...AN INC CHC OF PCPN EXISTS AS IT ENCOUNTERS DEEPER MSTR. A SHALLOW LYR OF RH REMAINS BHND THE FRONT...SO WASNT TOO QUICK TO CLR THE SKY TNGT. EVEN IN NWRN ZNS WHEN THE LOW CLDS SCOUR OUT...H7-H3 DCVA INDUCED ALTOCU TRAVERSES. MTNS MAY EXP A PD OF L- THIS EVNG INTO THE OVRNGT. MRNG HIGHS FOR ALL...SAVE FOR SERN AREAS FM BKW-I16-CWD. COLDER AIR RETURNS TNGT WITH FZ TEMPS. IT APPEARS ALL MEASURABLE AND NON-MEASURABLE PCPN WL BE GONE BY THE TIME FZ TEMPS ARRIVE. LONG TERM /TUESDAY THROUGH SUNDAY/... UNDER CUTTING OR REVERSE WARM ADVECTION PATTERN TAKES PLACE TUESDAY AS FRONT SAGS S...FOLLOWED BY SLOPING BAROCLINIC TRANSITION WITH EPV / MOISTURE ALIGNED WITH Q VECTOR CONVERGENCE AND WEAK FRONTOGENETIC FORCING NOW A BIT HIGHER IN THE ATMOSPHERE THAN INDICATED ON PREVIOUS MODEL RUNS. POPS MAXIMIZE IN SOUTHERN MOUNTAINS BRIEFLY TUESDAY MORNING AS AFOREMENTIONED FORCING IS COUPLED WITH UPSLOPE WNW FLOW. RESULTING SEEDER FEEDER COULD SUPPORT MEASURABLE PRECIPITATION THERE THEN. LOW LEVEL COLD AIR ARRIVING TUESDAY MORNING COULD GET MOUNTAIN TEMPERATURES DOWN TO FREEZING CLOSE TO THE TIME PRECIPITATION IS ENDING BUT BUFKIT SOUNDINGS SUGGEST THIS WILL TAKE PLACE JUST N OF WHERE DRY LAYER IS SHALLOW ENOUGH FOR SEEDER FEEDER. INCREASED CLOUDS AND POPS S PORTION OF AREA AND ADDED DRIZZLE...BUT DIMINISHED POPS BELOW 15 BY LATE AFTERNOON WHILE BRINGING IN CLEARING FROM THE N. HIGH PRESSURE SETTLES IN FOR TUESDAY NIGHT AND WEDNESDAY INTO WEDNESDAY NIGHT. SOME CLOUDS PERSIST IN MOUNTAINS TUESDAY INTO TUESDAY NIGHT BEFORE HIGH BUILDS IN AND CUTS OFF NW UPSLOPE FLOW. TIMING ON LATE SYSTEM ARRIVING FROM THE W THURSDAY AFTERNOON LOOKS REASONABLE WITH ONLY MINOR EDITS TO POPS DURING PEAK OF SYSTEM FRIDAY INTO FRIDAY NIGHT. MET IS UP A BIT FROM YESTERDAY FOR HIGHS TUESDAY BUT REMAINS LOWER THAN MAV...WITH THE FWC LOWER STILL. ADJUSTED UPWARD SLIGHTLY IN RESPONSE TO THE HIGHER MET. LOWS TUESDAY NIGHT LOOK GOOD WITH RADIATIVE COOLING. FORECAST VALUES ARE A BIT BELOW THE NUMBERS. MET AND MAV AS VERY MUCH DIVERGED ON HIGHS WEDNESDAY. THINK HIGHS WILL BE VERY SIMILAR TO THOSE TUESDAY...WHICH TAKES ME BETWEEN NUMBERS BUT A BIT CLOSER TO THE LOWER MET. LOWS WEDNESDAY NIGHT LOOKED GOOD WITH RADIATIVE COOLING TO START THE NIGHT...LOWERED MOUNTAIN VALLEYS A BIT. RAISED HIGHS TOWARD THE NEW MEX THURSDAY IN S DOWNSLOPE FLOW AND SOME SUNSHINE AHEAD OF NEXT SYSTEM. PREV DISCUSSION... /ISSUED 1252 AM EST MON DEC 18 2006/ AVIATION /06Z TO 06Z/... COLD FRONT TO AFFECT ALL SITES LTR THIS AFTN. NOT MUCH IN THE WAY OF PCPN OUTSIDE THE MTNS IS FCST...BUT CIGS WL LWR TO MVFR JUST AHD OF THE FRONT AND PERSIST MOST OF THE NGT. DRY AIR REACHES PKB BY THE END OF THE PD MEANING A RTN TO VFR. ANY VSBY RESTRICTIONS IN RW WL BE NO WORSE THAN MVFR. COLD FRONT TIMING IS AS FOLLOWS: PKB-HTS 15Z CKB-CRW-EKN 16-17Z BKW 18Z && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ AVIATION...29