Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 191800 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 200 PM EDT SUN APR 19 2015 .SYNOPSIS... WARM FRONT BRINGS SHOWERS AND STRONG WINDS TODAY...BEFORE MOVING THROUGH TONIGHT. COLD FRONT BRINGS SHOWERS AND STRONG STORMS MONDAY...FOLLOWED BY AN EXTENDED PERIOD OF COOLER WEATHER. && .NEAR TERM /THROUGH TONIGHT/... 11AM UPDATE... MADE SOME ADJUSTMENT TO THE POPS FOR THE AFTERNOON...AND WILL BE WATCHING THE QPF AMOUNTS IN THE NORTHEAST MOUNTAINS. PREVIOUS DISCUSSION... WARM FRONT OVER THE TN VALLEY EARLY THIS MORNING APPROACHES TODAY AND MOVES NEWD THROUGH THE FCST AREA TONIGHT...BRINGING ON A WET CLOSE TO THE WEEKEND. WRFARW APPEARED TO HAVE A GOOD HANDLE ON THE EVOLUTION OF THE RAIN ASSOCIATED WITH THE WARM FRONT. THE RAIN HAS MADE BETTER NWD PROGRESS OUT TO THE W EARLY THIS MORNING...AND EVEN THERE THE SHOWERS WERE RATHER LIGHT AND WIDELY SCATTERED BACK THROUGH CENTRAL KY. THEREFORE HAVE DELAYED THE ONSET OF PRECIPITATION FROM THE S AND W EARLY THIS MORNING. ALL NEAR TERM MODELS HAVE THE FCST AREA DRY THROUGH 12Z. WITH HIGH PRESSURE DRIVING A BACK DOOR DOWN THE E COAST...AND A WARM WAVE APPROACHING FROM THE WRN TN VALLEY...THE RESULTING TIGHTENING PRESSURE GRADIENT WILL CREATE STRONG WINDS THAT WILL MIX TO THE SFC AS THE WARM FRONT GETS CLOSE / MOVES THROUGH. IN ADDITION TO PRODUCING GUSTS UP TO AROUND 30 KTS TODAY...THESE STRONG WINDS...TO THE TUNE OF 60 KTS OR BETTER AT H85...WILL CREATE THE TYPICAL UPSLOPE DOWNSLOPE EFFECT...WITH A RAIN SHADOW JUST W OF THE MOUNTAINS...AND ENHANCED QPF E OF THE MOUNTAINS...THE BLUE RIDGE IN PARTICULAR. THIS IS IN AGREEMENT WITH THE WPC SLIGHT RISK AND RNK / LWX THINKING. THE WRFARW HAD BEEN INDICATING HEAVY PRECIPITATION INTO POCAHONTAS COUNTY BUT NOW KEEPS THE HEAVIEST E OF THE BLUE RIDGE THIS EVENING. THE WRFNMM IS HITTING THE POCAHONTAS / RANDOLPH LINE A LITTLE HARD THOUGH. AS THE WARM FRONT MOVES INTO THE AREA...TAPERING THE RAIN SHOWERS SW TO NE THIS EVENING...THERE WILL BE A WINDOW OF OPPORTUNITY FOR CONVECTION TO DEVELOP SW PORTION OF FCST AREA THAT COULD THEN TAKE ADVANTAGE OF THE STRONG FLOW...ESPECIALLY ALONG THE WARM FRONT IF THERE IS ENOUGH DIRECTIONAL SHEAR THERE. WILL MAINTAIN HWO MENTION THERE PER PREVIOUS PACKAGE AND SWODY1 FOR THIS EVENING. OTHERWISE THE CWA WILL TREND DRIER IN THE WARM SECTOR OVERNIGHT TONIGHT. USED A MET/MOSGUIDE/WRFARW BLEND FOR TEMPERATURES TODAY AND THIS EVENING AND A MET/MOSGUIDE BLEND TONIGHT...NOT MUCH CHANGE OVERALL BUT SUBTLE TIMING ADJUSTMENTS RELATIVE TO PRECIPITATION TODAY. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ACTIVE WEATHER CONTINUES IN THE SHORT TERM PERIODS AS ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS DEVELOP...AS A SURFACE COLD FRONT...AND UPPER SHORTWAVE TROUGH AFFECT THE AREA. THERE IS THE POSSIBILITY THAT SOME OF THE STORMS COULD BECOME SEVERE...AND IF ANY BREAKS ARE ABLE TO FORM IN THE CLOUD COVER ON MONDAY OUT AHEAD OF THE FRONT...THIS WILL ONLY HELP TO INCREASE THE INSTABILITY. MODELS INDICATING 30-40 KTS 0-6KM BULK SHEAR...AND UNIDIRECTIONAL WIND PROFILES...SUGGESTIVE OF STORMS CAPABLE OF PRODUCING DAMAGING WINDS. IN ADDITION...FZLVS AROUND 8000-9000 FEET SUGGESTED ON MODEL SOUNDINGS...ALONG WITH 1000-1500 J/KG CAPE...LARGE HAIL WILL ALSO BE A FACTOR IN ANY STORMS THAT ARE ABLE TO DEVELOP. SPC HAS HIGHLIGHTED THE EASTERN HALF OF THE CWA IN A SLIGHT RISK FOR SEVERE ON MONDAY AS A RESULT. COLD FRONT WILL BE TO THE EAST OF THE CWA LATE MONDAY NIGHT...WITH CALMER...BUT COOLER...WEATHER TAKING HOLD. UPPER LOW WILL LINGER ACROSS THE GREAT LAKES REGION FOR THE REMAINDER OF THE SHORT TERM PERIOD...AND THIS COMBINED WITH WAVES ROTATING AROUND THE LOW AT TIMES...WILL CREATE ADDITIONAL CHANCES FOR PRECIPITATION. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... OVERALL...WE LOOK TO BE COOLER THAN NORMAL...ESPECIALLY AT NIGHT THROUGH THE LONG TERM. BEST CHANCE FOR A FROST/FREEZE LOOKS TO BE FRIDAY MORNING AFTER A WEAK COLD FRONT PASSES THROUGH WEDNESDAY NIGHT OR THURSDAY. STUCK PRETTY CLOSE TO WPC FOR POPS/SKY/HIGH TEMPS. UNDERCUT WPC TEMPS A BIT ON OVERNIGHT LOWS. BOTH GFS AND ECMWF SHOW 850MB TEMPS BELOW ZERO LATE THIS WEEK INTO THIS WEEKEND. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... SOUTHEAST WINDS GUST TO 25-35KTS THROUGH 00Z...SUBSIDING SLOWLY TONIGHT. THESE WINDS WILL KEEP THE LOWER ATMOSPHERE TURBULENT ENOUGH TO KEEP IFR CEILINGS FROM FORMING...INCLUDING BKW...DESPITE PERSISTENT SHOWERS THROUGH THE NEXT 6 TO 12 HOURS. THE SAME LOGIC FOLLOWS THE VISIBILITIES THAT SHOULD ONLY DROP TO MVFR AT TIMES AS WELL. A COLD FRONT WILL COME THROUGH THE AREA AFTER 09Z MONDAY. SHOWERS AND STORMS WILL DEVELOP ALONG THIS COLD FRONT...ESPECIALLY WITH THE HELP OF DAYTIME HEATING HEADING INTO THE AFTERNOON HOURS. THUNDER POTENTIAL IS BETTER SOUTH AND EAST OF THE OHIO RIVER TERMINALS. COVERED THIS WITH VCTS/CB. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: BRIEF IFR POSSIBLE IN HEAVY RAIN...BUT SHOULD NOT LAST LONG. TIMING OF PRECIPITATION BEGINNING/END 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 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 M M H H H H H M H H BKW CONSISTENCY M H H H H H H H M M H H EKN CONSISTENCY H H H H H M M M H H H H PKB CONSISTENCY H H M M M 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 POSSIBLE MONDAY IN SHOWERS AND THUNDERSTORMS. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM/26 SHORT TERM...SL LONG TERM...MZ AVIATION...26

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