Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 081047 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 547 AM EST MON FEB 8 2016 .SYNOPSIS... COLD FRONT TODAY. 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 TONIGHT/... UPPER LEVEL LOW CONTINUES ITS SLOW TREK...DROPPING INTO THE GREAT LAKES AND MIDDLE OHIO VALLEY. SURFACE FRONTAL SYSTEM COUNTERPART WILL TAKE A COLD FRONT THROUGH THE AREA TODAY...FOLLOWED BY A SERIES OF UPPER LEVEL VORTICITY LOBES AND TROUGH AXES WELL INTO THE SHORT TERM FORECAST PERIOD. EXPECTING A SIGNIFICANT CHANGE IN AIRMASS IN TERMS OF TEMPERATURE WITH A PROLONGED PERIOD OF BELOW FREEZING WEATHER BEGINNING TONIGHT. SHOULD SEE A SLIGHTLY UNUSUAL PATTERN FOR THE TEMPERATURES AND PRECIPITATION TYPE AS THE DAY EVOLVES. MAY SEE A LITTLE LIGHT SNOW AT FIRST GIVEN THE POTENTIAL TO WET BULB...AS DEWPOINTS RESIDE IN THE LOW TO MID 20S CURRENTLY WHILE TEMPERATURES ARE IN THE UPPER 20S TO MID 30S. SHOULD TRANSITION TO RAIN AS TEMPERATURES CLIMB TO THE UPPER 30S AND LOWER 40S OVER THE LOWLANDS...AND FALL OFF BEHIND THE FRONT THIS EVENING AND TONIGHT...CHANGING BACK TO SNOW. THE HIGHER ELEVATIONS SHOULD NOT GET ABOVE FREEZING...SO THIS SHOULD BE AN ALL SNOW EVENT FRONT THE GET GO...AND HENCE...THE ADVISORY BEGINNING AT 18Z FOR RANDOLPH AND POCAHONTAS COUNTIES. 850MB TEMPERATURES DROP HARD TONIGHT IN THE TRANSITION TO A MUCH COLDER ENVIRONMENT THAT WILL SUPPORT THE OFF AND ON SNOW SHOWERS...BRIEFLY HEAVY AT TIMES. SHOULD NOT HAVE ANY ISSUES AT THE ONSET WITH SATURATION IN THE DENDRITE GROWTH LAYER...AND WILL SEE MODEST ACCUMULATIONS BEGINNING TONIGHT...ESPECIALLY OVER THE NORTHERN ZONES...AND IN THE NORTHEAST MOUNTAINS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... A DEEP LOW PRESSURE/TROUGH BRINGS A SERIES OF SHORT WAVES ACROSS THE AREA THROUGH THE PERIOD. THIS WILL CONTRIBUTE TO BELOW NORMAL TEMPERATURES AND PERIODS OF SNOW SHOWERS. THE GFS/ECMWF/NAM ARE IN AGREEMENT WITH THE TIMING AND INTENSITY OF THE PCPN. THE GFS/NAM SOLUTIONS SUGGEST SIGNIFICANT SNOWFALL TUESDAY AND WEDNESDAY...CONTINUING INTO THURSDAY. 2 TO 4 INCHES OF SNOW WILL BE COMMON...DEPENDING ON WHERE A SNOW BAND SET UP. OUTSIDE WIDESPREAD UPSLOPE SNOW SHOWERS...MODELS DEPICT A LAKE MI TRAJECTORY COMING ACROSS THE NRN TIER OF THE FCST AREA BY TUESDAY...ENHANCING LOWLAND SNOW AMOUNTS THERE VS. AREAS FARTHER S. WITH H85 TEMPERATURES DROPPING INTO THE TEENS BELOW ZERO C TUE AND SLOWLY DROPPING FURTHER BEYOND THAT...BELIEVE ALL PCPN WILL BE IN FORM OF SNOW. DESCENT OMEGA WITHIN THE DENDRITE SUGGEST LOCALIZED BURSTS OF SNOW ARE POSSIBLE WHERE OMEGA REACH 15 TO 20 MICRO BARS PER SECOND. 3 TO 5 INCHES OF SNOW CAN BE EXPECTED IN A TIME PERIOD OF 24 TO 36 HOURS. ISSUED WINTER WEATHER ADVISORY FOR MOST PLACES FOR SNOW WITH THE MODEL CONSENSUS. WENT GENERALLY WITH THE ALLBLEND AND SUPERBLEND FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /THURSDAY 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 DENDRITE 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 /12Z MONDAY THROUGH FRIDAY/...
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STILL EXPECTING DETERIORATING CONDITIONS TODAY WITH A COLD FRONT AND POST FRONTAL RAIN TURNING TO SNOW BY THIS EVENING/TONIGHT. PREVAILING MVFR TO IFR LIKELY FOR ALL SITES...ESPECIALLY ONCE THE LOWEST LEVELS SATURATED AFTER A FEW HOURS OF PRECIPITATION. THIS APPLIES TO BOTH CEILINGS AND VISIBILITIES. SNOW SHOWERS TONIGHT WILL ALSO CARRY PREVAILING IFR VISIBILITIES FOR ALL TERMINALS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE...HIGH IN THE DETERIORATING TRENDS...AND MEDIUM IN THE DETAILS AND TIMING. ALTERNATE SCENARIOS: TIMING OF IFR WILL VARY. LOW LEVEL SATURATION MAY REQUIRE EARLIER ONSET OF IFR ONCE THE COLD FRONT PASSES. MAY NEED A COUPLE HOURS OF IMPROVED FLIGHT CATEGORIES LATER TODAY. 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 02/08/16 UTC 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 EST 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16 CRW CONSISTENCY H H M M M L L L L L M M HTS CONSISTENCY H M M L L L L M M M M M BKW CONSISTENCY H H H M M L L L L L L L EKN CONSISTENCY H H H H H H H M M L L L PKB CONSISTENCY H H H M M L L L L M M M CKB CONSISTENCY H H H H H H M M M M L L AFTER 12Z TUESDAY... PERIODS OF IFR CONDITIONS POSSIBLE IN RAIN/SNOW SHOWERS ALL THE WAY THROUGH WEDNESDAY NIGHT...WITH THE WORST CONDITIONS EXPECTED TUESDAY MORNING THROUGH WEDNESDAY MORNING.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR WVZ005>011-013>020-024>040. WINTER WEATHER ADVISORY FROM NOON TODAY TO 7 AM EST WEDNESDAY FOR WVZ046-047. OH...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR OHZ066-067-075-076-083>087. KY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR KYZ101>103-105. VA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR VAZ003-004. && $$ SYNOPSIS...ARJ/26 NEAR TERM...26 SHORT TERM...ARJ LONG TERM...30 AVIATION...26

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