623 FXUS61 KRLX 211042 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 642 AM EDT THU JUN 21 2012 .SYNOPSIS... UPPER RIDGE MOVES EAST TODAY. COLD FRONT CROSSES FRIDAY. AN INCREASE IN SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FRONT. COOLER TEMPERATURES FOLLOW. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... BATCH OF MID LEVEL MOISTURE WITH SOME ASSOCIATED LIFT HAS PRODUCED SPRINKLES OVER SOUTHEAST OHIO...WHICH SHOULD END IN THE NEXT COUPLE OF HOURS. OTHERWISE...NO MAJOR CHANGES. PREVIOUS DISCUSSION... UPPER RIDGE SLIDES EAST MARKING THE SLOW TRANSITION INTO A SLOW PATTERN CHANGE FROM THE VERY WARM AIRMASS IN PLACE OVER THE PAST FEW DAYS. FORECAST SOUNDINGS SHOW INSTABILITY THROUGH AROUND 650MB TODAY...WITH SOME DEFINED FRONTOGENETIC FORCING ALONG THE OHIO RIVER VALLEY AND IN THE MOUNTAINS. HAVE CONCENTRATED THE HIGHER CHANCE POPS TODAY IN THESE LOCATIONS...BUT WILL CARRY THE SLIGHT CHANCE ELSEWHERE WITH STORM MOTION. BROAD UPPER LEVEL TROUGH WILL ADVECT FROM THE WEST TONIGHT WITH A COLD FRONT TRACKING FROM THE GREAT LAKES TOWARDS THE OHIO VALLEY. WILL SLOW DOWN THE POPS A LITTLE BIT FROM PREVIOUS FORECAST WITH THE FRONT DECELERATING DURING THE NIGHT...POSSIBLY DUE TO A VORT MAX RIDING ALONG THE WEAK TROUGH AXIS. THIS WILL HELP KEEP THE THREAT FOR CONVECTION GOING DURING THE NIGHT AS IT ENTERS THE NORTHWESTERN ZONES OF SOUTHEAST OHIO. DESPITE THE PATTERN CHANGE ON ITS WAY...THERE WILL BE ONE LAST DAY OF 90F PLUS WEATHER FOR THE LOWLANDS. WILL TICK THESE NUMBERS DOWN A NOTCH OR TWO FROM THE PREVIOUS DAY WITH MORE EXPECTED CLOUD COVER TODAY. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... OTHER THAN SLIGHT TIMING DIFFERENCES AMONG THE MODELS...A COOL FRONT PUSHES STEADILY EASTWARD ACROSS THE AREA ON FRIDAY TO END THE HEAT. DESPITE THE POOR DIURNAL TIMING OF THE FRONT...MAINLY FRIDAY MORNING INTO EARLY AFTERNOON...ENOUGH UPPER SUPPORT AND CERTAINLY ENOUGH MOISTURE TRANSLATE TO LIKELY POPS AS WE FOLLOW THE FRONT ON FRIDAY. ALTHOUGH SCATTERED CONVECTION MAY OCCUR IN THE SOUPY AIRMASS AHEAD OF THE FRONT...MODELS HAVE THE ORGANIZED CONVECTION ALONG AND BEHIND THE FRONT. WILL INCLUDE CHANCE OF THUNDER...AS MODELS INDICATE AT LEAST ELEVATED INSTABILITY. WE EXPECT A RATHER SHARP BACK EDGE TO THE ORGANIZED CONVECTION AS HIGH PRESSURE BUILDS IN...WITH MOST OF THE SHOWERS ENDING IN THE WESTERN PARTS BY MID AFTERNOON. BY FRIDAY EVENING...BACK EDGE OF THE ORGANIZED CONVECTION WILL BE CROSSING THE MOUNTAINS...THEN EXITING THE AREA TO THE EAST EARLY FRIDAY NIGHT. FRIDAY TEMPERATURES WILL MAINLY BE IN THE 80S WITH ALL THE CLOUDS AND SHOWERS. DRIER AIR MOVES IN FRIDAY NIGHT WITH COOLER TEMPERATURES ON WEAK COLD ADVECTION. THE WEEKEND LOOKS TO BE DRY AS HIGH PRESSURE RULES. FOR THE LOW LANDS...MODEL CONSENSUS HAS TEMPERATURES IN THE 80S FOR HIGHS UNDER ABUNDANT SUNSHINE...AND MUCH LESS HUMIDITY. LOWS WILL BE FARTHER DOWN INTO THE LOW TO MID 60S. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... UNSETTLED BUT COOLER WEATHER IS EXPECTED IN THE LONG TERM AS AN UPPER LOW DROPS SOUTH OUT OF CANADA...DEEPENING AN UPPER LEVEL TROUGH ACROSS THE EASTERN U.S. EARLY NEXT WEEK. GFS TENDS TO INDICATE A DEEPER TROUGH DEVELOPING ACROSS THE EASTERN U.S. THAN OTHER MODELS SUCH AS THE ECMWF...BUT ECMWF HAS HAD RUN TO RUN INCONSISTENCIES IN THE HANDLING OF THIS FEATURE. REGARDLESS...A COOLER BUT UNSETTLED PERIOD IS EXPECTED ACROSS THE AREA IN THE LONG TERM. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... ISOLATED TO SCATTERED CONVECTION EXPECTED THIS AFTERNOON...BUT LOWER POPS GIVE ONLY ENOUGH CONFIDENCE FOR VCTS/CB IN THE TAFS THIS MORNING. CLOUD COVER TO HANG ON TONIGHT TO SOME DEGREE...SO WILL NOT INCLUDE ANY FOG FOR THIS ISSUANCE. WILL ALSO NEED TO ASSESS IF RAINFALL OCCURS AT TERMINALS TODAY...WHICH COULD INCREASE THE CHANCE FOR MIST OR FOG TONIGHT. OTHERWISE...VFR CUMULUS...SOME TOWERING...TODAY IN LIGHT SOUTHWESTERLY TO WESTERLY SURFACE FLOW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: MAY NEED SHRA/TSRA WITH CONVECTION. AMENDMENTS MAY BE NEEDED. MAY NEED TO UP THE VISIBILITY RESTRICTIONS TONIGHT. 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 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY H L H H H H H H H H H H HTS CONSISTENCY L L 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 L L L L 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 12Z FRIDAY... NO WIDESPREAD AREAS OF IFR EXPECTED AT THIS TIME. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JMV/26 NEAR TERM...26 SHORT TERM...JMV LONG TERM...SL AVIATION...26