Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 080006 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 706 PM EST SUN FEB 7 2016 .SYNOPSIS... HIGH PRESSURE EXITS TONIGHT. COLD FRONT MONDAY. UNSETTLED/COLDER TUESDAY AND WEDNESDAY UNDER LARGE MID/UPPER LEVEL LOW...WITH ROUNDS OF SNOW SHOWERS THAT LINGER THROUGH MUCH OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... 700PM UPDATE...OPTED TO KEEP A MORE PREDOMINATELY RAIN MIXTURE ON MONDAY MORNING...BASED ON LATEST GUIDANCE WHICH KEEPS A FAIRLY DEEP WARM LAYER BELOW 850MB. UPPER LOW DIGS DOWN FROM THE UPPER MIDWEST TONIGHT WITH AN ASSOCIATED SURFACE LOW AND TRAILING COLD FRONT. COLD FRONT PASSES THE REGION TOMORROW BRINGING RAIN AND SNOW SHOWERS WITH IT. PRECIPITATION WILL ENTER THE OHIO VALLEY AROUND DAYBREAK AND SPREAD EASTWARD FROM THERE. FORECAST CONFIDENCE IS FAIRLY HIGH ON THE TIMING OF FROPA BUT STILL SOME UNCERTAINTY WITH REGARD TO P-TYPES. CURRENT THINKING IS THAT BEFORE THE FRONT ARRIVES MOST OF THE REGION SHOULD BE ABOVE FREEZING...HOWEVER AS HEAVIEST PRECIP MOVES OVERHEAD WET-BULBING IN AREA OF GREATEST FORCING COULD DROP SURFACE TEMPERATURES ENOUGH FOR A QUICK BURST OF WET SNOW TO OCCUR IN THE LOWLANDS. THIS WILL LIKELY ONLY BE WITH THE HEAVIEST BAND OF PRECIPITATION AND AFTER THE BEST FORCING MOVES THROUGH...EXPECTING JUST PLAIN RAIN SHOWERS OUTSIDE OF THE HIGHER TERRAIN. AS FAR AS ACCUMULATION GOES THROUGH 00Z TUESDAY...IT LOOKS LIKE 1 TO 2 INCHES WILL BE POSSIBLE IN THE MOUNTAINS AND GENERALLY A HALF INCH OR LESS IN THE LOWLANDS. DUE TO THE UNCERTAINTY WITH BOUNDARY LAYERS TEMPERATURES...ON- COMING SHIFTS WILL JUST HAVE TO MONITOR HOW THE EVENT UNFOLDS AND AN SPS FOR A BRIEF PERIOD OF HEAVY SNOW TOMORROW MORNING COULD BE POSSIBLE. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... DEEP L/W TROUGH OVER THE ERN U.S. THIS ENTIRE PERIOD SPELLS BELOW NORMAL TEMPERATURES AND SNOW SHOWERS. THE PARTY BEGINS RIGHT AT THE START OF THE PERIOD MON NT...WITH COLD ADVECTION OVERSPREADING THE AREA FROM SW TO NE...BEHIND A NW TO SE ORIENTED SFC LOW PRESSURE TROUGH EXTENDING FROM THE ERN GREAT LAKES TO THE DELMARVA PENINSULA BY 12Z TUE. OUTSIDE WIDESPREAD UPSLOPE SNOW SHOWERS...MODELS DEPICT A LAKE MI TRAJECTORY COMING ACROSS THE NRN TIER OF THE FCST AREA MON NT INTO TUE...ENHANCING LOWLAND SNOW AMOUNTS THERE VS. AREAS FARTHER S. BEYOND THAT...TOUGH TO TIME THE SMALLER SCALE FEATURES ROTATING AROUND THE EVOLVING UPPER LOW NEARBY TO THE N...BUT IT LOOKS LIKE THE GENERAL TRAJECTORIES MAY NOT CHANGE MUCH. WITH H85 TEMPERATURES DROPPING INTO THE TEENS BELOW ZERO C TUE AND SLOWLY DROPPING FURTHER BEYOND THAT...DENDRITIC CRYSTAL GROWTH IS FAVORED...RESULTING IN HIGH SNOW TO LIQUID RATIOS. FOR STARTERS...SNOW TOTALS FOR MON NT THROUGH TUE ARE CLOSE TO 12 HOUR ADVISORY CRITERIA BUT 3-5 INCHES SHORT OF WARNING CRITERIA ON A COUNTY AVERAGE BASIS THROUGHOUT THE FCST AREA. THUS NOT INTRODUCING ANY HEADLINES AT THIS TIME ALTHOUGH IT IS PLAUSIBLE ADVISORIES WILL BE NEEDED FOR THAT PERIOD...AND THEN TUE NT INTO WED LOOK TO BE NEARLY AS SNOWY WITH THE UPPER LEVEL LOW AND L/W TROUGH AXIS STILL OVER THE UPPER AND MIDDLE OHIO VALLEYS. THE LAKE MI TRAJECTORY INTO NRN PORTIONS OF THE FCST AREA MAY STILL BE THERE OR MAY BE BECOMING REESTABLISHED WED AFTERNOON. TEMPERATURES WERE LOWER THAN GUIDANCE BUT GENERALLY STAYED CLOSE TO PREVIOUS PACKAGE AND RAW GUIDANCE IN THIS ANOMALOUS PNA PATTERN...PERHAPS JUST SLOWING DOWN THE COOLING A BIT MON NT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... STILL EXPECTING SCT SNOW SHOWERS OVER THE AREA WEDNESDAY NIGHT. STREAMLINE ANALYSIS AND HYSPLIT BACKWARDS TRAJECTORY PARCELS ALONG WITH OMEGA/RH IN THE DENDRITIC GROWTH ZONE DO INDICATE SOME ENHANCEMENT FROM LAKE MICHIGAN FOR A TIME IN THE EVENING...AFFECTING SE OH AND ESPECIALLY N WV. THIS IS ENHANCED FURTHER WITH A SUBTLE VORT MAX ROUNDING THE BASE OF THE UPPER TROF. SO...HAVE KEPT SOME FAIRLY HEALTHY POPS OVER THE N DURING THE NIGHT. HOWEVER...EXPECT THIS TO BE A LOW QPF/HIGH POP SCENARIO WITH GREATEST ACCUMULATIONS WEDNESDAY NIGHT OVER THE N WV MOUNTAINS WHERE AN INCH OR TWO OF ADDITIONAL SNOW MAY FALL. THURSDAY MORNING WILL FEATURE SOME LINGERING SNOW SHOWERS AND FLURRIES...PRIMARILY WITHIN ANY LAKE MICHIGAN PLUME AS SHOWN ON GFS. H85 THERMAL TROF LINGERS IN THE VICINITY SO HARD TO SEE MUCH IN THE WAY OF IMPROVEMENT WITH THE EROSION OF THE STRATOCU AND ANY TEMPERATURE MODERATION. WE FINALLY GET SOME WAA GOING THURSDAY NIGHT WHICH SHOULD BE ENOUGH FOR SOME CLEARING AREAWIDE. AT THE SURFACE HIGH PRESSURE WILL BE BUILDING IN WHICH WILL MAKE FOR A VERY COLD NIGHT SHOULD WE INDEED LOSE THE CLOUDS AMID A FRESH SNOW PACK. SOME BELOW ZERO READINGS ARE POSSIBLE IN THE IN THE TYPICAL COLD SPOTS OF THE MOUNTAIN VALLEYS. CONFIDENCE BEGINS TO DECREASE HEADING INTO THE WEEKEND. THE GLOBAL MODELS ARE HAVING SOME ISSUES RESOLVING FEATURES AND THE OVERALL MEAN TROF OVER THE EASTERN CONUS. THUS HAVE STAYED CLOSE TO WPC WHICH FAVORED A COLDER ECMWF SOLUTION FOR THE WEEKEND AMID ANOTHER ARCTIC HAMMER DROP. NO BIG SYSTEM IS ENVISIONED OVER THE WEEKEND THOUGH. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... CLOUDS WILL BE ON THE INCREASE TONIGHT AS COLD FRONT APPROACHES THE AREA FROM THE WEST. RAIN OR SNOW SHOWERS WILL ENTER THE OHIO VALLEY BY DAYBREAK AND SPREAD EASTWARD THROUGH THE DAY. MVFR WITH INCREASING CHANCES OF IFR. ALL TERMINALS WILL LIKELY STAY BELOW VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: TEMPERATURES MAY BE COOL ENOUGH TO HAVE IFR SNOW. 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 MON UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 CRW CONSISTENCY H H H H H H H H H H H M HTS CONSISTENCY H H H H H H H H H H M M BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H H AFTER 00Z TUESDAY... MVFR TO PERIODS OF IFR CONDITIONS POSSIBLE IN RAIN/SNOW SHOWERS ALL THE WAY INTO WEDNESDAY...WITH THE WORST CONDITIONS EXPECTED TUESDAY MORNING THROUGH WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/MPK/30 NEAR TERM...MPK SHORT TERM...TRM LONG TERM...30 AVIATION...JW

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