Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 281838 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 138 PM EST SAT FEB 28 2015 .SYNOPSIS...
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WARM FRONT LATE TONIGHT INTO SUNDAY. COLD FRONT SUNDAY NIGHT. HIGH PRESSURE BRINGS DRIER WEATHER MONDAY INTO MONDAY NIGHT. ANOTHER WARM/COLD FRONT COMBO TUESDAY INTO WEDNESDAY.
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&& .NEAR TERM /THROUGH SUNDAY/... WARM ADVECTION S FLOW INTO AN ARCTIC AIR MASS...ON THE BACK SIDE OF THE EXITING ARCTIC HIGH...WILL CREATE MIXED PRECIPITATION IN THE AREA OVERNIGHT TONIGHT AND SUNDAY..BENEATH FLAT UPPER LEVEL SW FLOW.. PRECIPITATION SHOULD SPREAD INTO THE OHIO VALLEY AFTER MIDNIGHT TONIGHT. MODELS WARM THE LAYERS ABOVE FREEZING MORE OR LESS AT THE SAME TIME ALTHOUGH BUFKIT SOUNDINGS DO SUGGEST A SHALLOW LAYER OF COLD AIR HANGING ON INTO SUNDAY AFTERNOON ESPECIALLY TO THE NW OF THE OHIO RIVER...AND IN THE GREENBRIER VALLEY. STILL GETTING AROUND 2 INCHES SNOW PERRY AND MORGAN COUNTIES TO KEEP THE ADVISORY GOING THERE...WITH A TOUCH OF FREEZING RAIN POSSIBLE THERE IN THE TRANSITION. ALSO CONSIDERING ADVISORY FOR FREEZING RAIN OVER THE EASTERN SLOPES OF OUR WV MOUNTAIN COUNTIES OF POCAHONTAS...FAYETTE AND RANDOLPH COUNTIES. WILL CONSIDER EXPANSION OF ADVISORY TO THESE COUNTIES IN COORD WITH NEIGHBORS THIS AFTERNOON. ANY FREEZING RAIN ELSEWHERE IS EXPECTED TO BE BRIEF AND RELATIVELY INCONSEQUENTIAL. USED NAM / MET BLENDED WITH PREVIOUS RUN FOR TEMPERATURES AND DEW POINTS. DO HOLD ON THE COLD AIR A LITTLE LONGER IN SE OHIO AND IN THE GREENBRIER VALLEY ON SUNDAY. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
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SOME COLD AIR ADVECTION CONTINUES SUNDAY NIGHT UNDER NORTHWEST FLOW BEHIND FIRST COLD FRONT TRANSITIONING PCPN INTO A MIX OR SNOW WITH LINGERING MOISTURE. PCPN SHOULD BRIEFLY END SUNDAY NIGHT BEFORE NEXT SYSTEM APPROACHES. A BRIEF HIGH PRESSURE WILL CROSS THE AREA MONDAY NIGHT WITH DRY WEATHER. BY LATE SUNDAY NIGHT INTO MONDAY...FLOW BECOMES SOUTHWEST TO BRING WAA. A WARM FRONT LIFTS NORTH LATE MONDAY NIGHT NIGHT INTO TUESDAY...TO BRING CHANCES OF PCPN TO THE AREA. BUFKIT SOUNDINGS FROM THE GFS SUGGEST ONSET OF PCPN AS FZRA ACROSS THE SOUTHERN THIRD OF THE AREA EARLY TUESDAY MORNING BEFORE SWITCHING TO RAIN. MODELS INDICATE STRONG WARM AIR ADVECTION AT H850 UNDER AROUND 50 KNOTS FROM THE SOUTHWEST WITH TEMPERATURES INCREASING FROM 4C TO 9C BY 06 WEDNESDAY. THEREFORE...EXPECT MOST PCPN IN THE FORM OF RAIN THROUGH TUESDAY NIGHT. A BRIEF WINTER WEATHER ADVISORY MAY BE REQUIRED FOR THAT AREA FOR FREEZING RAIN TUESDAY MORNING. CONCERNS CONTINUES AS EXTENDED PERIOD OF RAIN IS FORECAST TUESDAY INTO MID WEEK. WITH WET TERRAIN...SNOW PACK AND WHATEVER RAINFALL AMOUNTS OCCUR...FLOODING THREAT INCREASES TUESDAY INTO WEDNESDAY. THERE IS MORE LIQUID EQUIVALENT IN THE DEEPER SNOW PACK OVER THE EASTERN MOUNTAINS...WHERE FLOODING IS MORE LIKELY. KEPT HIGH POPS WITH THE AFOREMENTIONED SYSTEM RANGING FROM CATEGORICAL SOUTHEAST OH...AND WESTERN HALF OF WV INCLUDING THE NORTHEAST MOUNTAINS AHEAD OF AN APPROACHING COLD FRONT. H850 WINDS INCREASE TO NEAR 70 KNOTS BY THE END OF THE PERIOD WITH STRONG WAA AHEAD OF THE FRONT. WEND WITH BIAS CORRECTED CONSENSUS MOS BLENDED WITH ALL BLEND GUIDANCE THROUGH THE PERIOD.
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&& .LONG TERM /WEDNESDAY THROUGH SATURDAY/...
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MODELS STARTING TO COME INTO BETTER AGREEMENT WITH EACH OTHER IN TERMS OF OVERALL PATTERN...ALTHOUGH TIMING ISSUES REMAIN. BRIEF BREAK IN THE PRECIPITATION EXPECTED FOR THE FIRST PART OF TUESDAY...AS HIGH PRESSURE HOLDS ON A LITTLE LONGER. HOWEVER...THIS WILL CHANGE AS A WARM FRONTAL BOUNDARY LIFTS NORTH ACROSS THE REGION. DEPENDING ON SURFACE TEMPERATURES...COULD SEE A BRIEF PERIOD OF FREEZING RAIN OR EVEN SLEET AT THE ONSET TUESDAY...BEFORE ENOUGH WARM AIR IS ABLE TO SURGE NORTH TO SCOUR OUT COLDER SURFACE TEMPERATURES. STILL LOOKING LIKE GOOD TAP OF GULF MOISTURE SURGING INTO THE REGION TUESDAY INTO WEDNESDAY WITH STRONG SOUTHWESTERLY WINDS DEVELOPING...WITH PW VALUES EXPECTED TO RISE AROUND 1.2 TO 1.3 INCHES...OR ABOUT 3 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. THIS...ALONG WITH THE STRONG DYNAMICS...WILL RESULT IN HEAVY RAIN ACROSS THE AREA...WITH A GENERAL 1 TO 2 INCHES OF RAIN EXPECTED...WITH THE HIGHER AMOUNTS AT THIS POINT EXPECTED ACROSS WV LOWLANDS AND SOUTHEAST OHIO. THE HEAVY RAIN...COMBINED WITH ANY SNOW MELT THAT IS ABLE TO OCCUR DUE TO WARMING TEMPERATURES...COULD CREATE FLOODING ISSUES. THERE IS A GENERAL 2 TO 4 INCHES OF WATER IN THE SNOW PACK ACROSS THE MOUNTAINS. OF COURSE THERE IS STILL UNCERTAINTY AS TO HOW MUCH SNOW MELT WILL OCCUR AND HOW RAPID IT WILL BE. WILL NEED TO MONITOR AREA CREEKS AND STREAMS INITIALLY WITH THIS SYSTEM...AND POSSIBLY RIVERS AS TIME PROGRESSES. THE GOOD NEWS IS...MODELS HAVE TRENDED TOWARDS A MORE SOUTHERLY TRACK WITH THE LOW THAT WILL DEVELOP AND PUSH ACROSS THE SOUTHEAST U.S. MID WEEK. THIS SHOULD HOPEFULLY KEEP THE BULK OF MOISTURE WITH THAT LOW TO OUR SOUTH. COLD FRONT WILL PUSH THROUGH THE CWA WEDNESDAY OR EARLY THURSDAY...WITH A GENERAL DRYING TREND TAKING HOLD AS HIGH PRESSURE BUILDS IN FROM THE WEST. ANY PRECIPITATION WILL CHANGE OVER TO LIGHT SNOWFALL BEHIND THE FRONT. WILL CONTINUE TO MENTION FLOODING POTENTIAL IN THE HWO FOR THE TIME PERIOD.
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&& .AVIATION /19Z SATURDAY THROUGH THURSDAY/...
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VFR FINISH TO THE DAY AS THE LAST MAJOR ARCTIC AIR MASS OF THE SEASON LEAVES THE AREA. THIS WILL GIVE WAY TO WARM ADVECTION TONIGHT AND SUNDAY...AS A WEAK LOW PRESSURE SYSTEM MOVES UP THE OHIO RIVER VALLEY. THIS WILL PUMP MOISTURE AND MILDER AIR INTO THE AREA. SNOW IS LIKELY TO OVERSPREAD THE MIDDLE OHIO VALLEY OVERNIGHT TONIGHT AND THEN MIX WITH SLEET...THEN BRIEFLY TO FREEZING RAIN...AND THEN ALL RAIN BY 18Z SUNDAY. ANOTHER WEAK DISTURBANCE MOVING UP FROM THE S WILL BRING SNOW AND SLEET TO THE NRN WV MOUNTAINS EARLY SUNDAY MORNING WITH SLEET...FREEZING RAIN AND RAIN INTO THE SOUTHERN AND CENTRAL WV MOUNTAINS. THE PRECIPITATION IN THE MOUNTAINS WILL ALSO GO TO RAIN BY 18Z SUNDAY...SAVE FOR PERHAPS THE HIGHEST TERRAIN AND ERN SLOPES...WHERE A MIX MAY PERSIST. CIGS WILL DROP TO MVFR SUNDAY MORNING WITH LOW MVFR MOST PLACES BY 18Z SUNDAY. EXPECT MVFR VSBY IN PRECIPITATION SUNDAY MORNING BUT IFR SNOW WILL BE CLOSE BY PKB...TO THE W OF THE OHIO RIVER...AND IN THE HIGHER TERRAIN. LIGHT AND VARIABLE SFC FLOW WILL HAVE MOSTLY AN ERLY COMPONENT...A LITTLE STRONGER SE IN THE MOUNTAINS. LIGHT SW FLOW ALOFT WILL BECOME MODERATE SW OVERNIGHT TONIGHT AND THEN REMAIN SO ON SUNDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS: TIMING OF ONSET OF PRECIPITATION AND ASSOCIATED LOWER CIGS AND VSBYS COULD VARY. IFR SNOW COULD GET INTO PKB SUNDAY MORNING. MUCH OF THE MOS GUIDANCE IS SUGGESTING IFR CIGS AND VSBYS BY MIDDAY SUNDAY. 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 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H 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 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 H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z SUNDAY... IFR POSSIBLE IN RAIN OR MIXED RAIN/SNOW LATE SUNDAY INTO EARLY MONDAY. IFR POSSIBLE AGAIN IN RAIN SHOWERS TUESDAY INTO WEDNESDAY.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...WINTER WEATHER ADVISORY FROM 1 AM TO 1 PM EST SUNDAY FOR OHZ066-067. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/RPY/SL/30 NEAR TERM...TRM SHORT TERM...ARJ LONG TERM...SL AVIATION...TRM

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