Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 021043 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 543 AM EST MON MAR 2 2015 .SYNOPSIS... A COLD FRONT THAT EXTENDED FROM EASTERN PENNSYLVANIA TO EAST TENNESSEE WILL CONTINUE TO MOVE EAST AND OFF THE COAST THIS MORNING. HIGH PRESSURE WILL FOLLOW BEHIND THE FRONT...CROSSING THE OHIO VALLEY TONIGHT AND EXTENDING SOUTH INTO THE MID ATLANTIC REGION TONIGHT. A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS ON TUESDAY WILL MOVE NORTHEAST AND WILL PUSH A STRONG COLD FRONT THROUGH OUR AREA ON WEDNESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 500 AM EST MONDAY... A COLD FRONT COMES THROUGH THE MORNING AND WILL BE EAST OF THE FORECAST AREA BY NOON. MODELS HOLD A MAJORITY OF THE PRECIPITATION ALONG AND AHEAD OF THE FRONT IN THE FAR WESTERN COUNTY WARNING AREA THIS MORNING. PUSH OF DRIER AIR BEHIND THE FRONT WILL BE ENOUGH TO END CHANCE OF PRECIPITATION AND CLEAR OUR MUCH OF THE FOG AND CLOUD COVER THIS AFTERNOON. HIGH PRESSURE MOVES ACROSS THE OHIO VALLEY TODAY AND WEDGES DOWN THE EAST SLOPES OF THE APPALACHIANS TONIGHT. 850 MB WINDS BEHIND THE FRONT WILL BE 45 TO 55 KNOTS WITH PRESSURE RISES 5 TO 7 MB/6 HOURS THIS MORNING. WILL HAVE WINDS GUSTING JUST BELOW ADVISORY LEVEL...UP TO 50 MPH THIS MORNING. WINDS DIMINISH THIS AFTERNOON AND THE TURN TO THE EAST THEN SOUTHEAST TONIGHT AS THE WEDGE BECOMES ESTABLISHED. THE EAST TO SOUTHEAST WINDS WILL BRING LOW LEVEL MOISTURE BACK NORTH ALONG THE BLUE RIDGE AND EASTERN SLOPES OVERNIGHT. COLDER AIR COMES IN BEHIND THE FRONT TODAY...BUT WITH SHRINKING AREAL COVERAGE OF PRECIPITATION AND SOME SUN IN THE AFTERNOON...TEMPERATURES WILL HOLD STEADY OR SLOWLY RISE. AS WIND DROPS OFF THIS EVENING...TEMPERATURES WILL COOL BUT AS CLOUD FILL BACK IN LATE TONIGHT DROP IN TEMPERATURES WILL BE LIMITED. HAVE ADDED PATCHY DRIZZLE AND FREEZING DRIZZLE AFTER MIDNIGHT FOR THE TYPICAL UPSLOPE AREA ALONG AND EAST OF THE SOUTHERN BLUE RIDGE. BUFKIT SHOWED A WARM NOSE AROUND 3000 FT AGL AND SURFACE TEMPERATURES DROPPING BELOW FREEZING. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... AS OF 500 AM EST MONDAY... WE WILL START OUT TUESDAY DEALING WITH ANOTHER WEDGE SITUATION SIMILAR TO WHAT WE JUST WENT THROUGH ON SUNDAY...BUT WITH MORE SYNOPTIC PRECIPITATION TO DEAL WITH. COLD HIGH PRESSURE WEDGES DOWN THE EASTERN SEABOARD WILL GET OVER RUN BY MUCH WARMER AIR AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. SOUNDINGS ON BUFKIT SHOW THE DEPTH OF THE COLD AIR IN THE BOUNDARY LAYER TO BE SUBSTANTIALLY DEEP AND COLD AT THE ONSET OF PRECIPITATION. THIS WILL FAVOR SOME SLEET AND HELP KEEP DOWN ICING ACCUMULATIONS FROM FREEZING RAIN AS PRECIPITATION MOVES IN. AS IS TYPICALLY THE CASE...THE WARMER AIR WILL MOVE IN FROM THE SOUTHWEST WITH GOOD WARMING AND THE LEAST POTENTIAL FOR ICING FROM THE MOUNTAIN EMPIRE AND GRAYSON HIGHLANDS OF VA INTO THE NW MOUNTAINS OF NC. EXPECTING THE WARMER AIR TO INTRUDE INTO THE NEW RIVER AND ROANOKE VALLEYS DURING THE AFTERNOON...BUT THE COLD AIR WILL MODERATE ONLY SLOWLY ACROSS THE GREENBRIER VALLEY...ALLEGHANY HIGHLANDS...AND PIEDMONTS OF NC/VA. HOWEVER...EVEN THIS SLIGHT TEMPERATURE MODERATION SHOULD BE ENOUGH TO END THE THREAT OF FREEZING RAIN FOR THE VAST MAJORITY OF THE AREA BY MID TO LATE AFTERNOON WITH TEMPS IN THE LOW TO MID 30S. RAIN WILL CONTINUE ACROSS THE REGION AS THE FRONT APPROACHES TUESDAY NIGHT BEFORE IT MOVES THROUGH ON WEDNESDAY. BASED ON THE LATEST QPF FORECASTS AND EXPECTED SNOW MELT...CURRENT HYDROLOGIC MODELS DO NOT INDICATE A SIGNIFICANT RIVER FLOOD THREAT BUT SMALLER STREAMS AND CREEKS ARE STILL A CONCERN. HOWEVER...CONSENSUS TIMING OF THE FRONTAL PASSAGE IS NOT CLEAR CUT AND BELIEVE IT BEST TO WAIT FOR LATER MODEL RUNS BEFORE DECIDING IF ANY HYDRO WATCHES ARE NEEDED. AS COLDER AIR MOVES IN BEHIND THE FRONT ON BLUSTERY NORTHWEST WINDS CONDITIONS APPEAR FAVORABLE FOR A BURST OF SNOW AS THE COLD AIR CATCHES UP TO THE BACK EDGE OF PRECIPITATION STARTING ON WEDNESDAY NIGHT AND CONTINUING INTO THURSDAY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT. IT LOOKS TO BE A FINE LINE BETWEEN WHERE THE AIR TEMPERATURES WILL SUPPORT SNOW AND WHERE THE HIGHEST PRECIPITATION WILL BE. THE MOST LIKELY LOCATION TO RECEIVE SEVERAL INCHES OF WET SNOW CURRENTLY APPEARS TO BE 30 MILES OR SO EITHER SIDE OF THE BLUE RIDGE...BUT THIS WILL LIKELY CHANGE AS THE SITUATION DEVELOPS. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... AS OF 130 PM EST SUNDAY... THURSDAY NIGHT...SOME LINGERING SNOW SHOWER WILL STILL BE POSSIBLE EAST OF THE BLUE RIDGE. HOWEVER...BY MIDNIGHT...PRECIPITATION IS EXPECTED TO COME TO AN END...AND CLOUD COVER ACROSS THE ENTIRE REGION WILL TREND FROM CLOUDY TO PARTLY CLOUDY THROUGH THE NIGHT. LOW TEMPERATURES WILL RANGE FROM THE SINGLE DIGITS TO THE LOWER TEENS ACROSS THE MOUNTAINS WITH MID TO UPPER TEENS ACROSS THE PIEDMONT. FRIDAY INTO SATURDAY...A BROAD AREA OF HIGH PRESSURE IS EXPECTED TO BUILD INTO...OVER...AND THEN EAST OF THE AREA. THIS WILL HAVE THE IMPACT TO KEEP OUR REGION PRECIPITATION FREE WITH A TREND FROM COLDER CONDITIONS TO MILDER CONDITIONS AS WE START GETTING ON THE RETURN SIDE SW-W FLOW OF THE HIGH BY SATURDAY AFTERNOON. THE TREND WILL CONTINUE INTO SUNDAY WITH NO PRECIPITATION AND EVEN MILDER CONDITIONS AS A TROUGH DEEPENS IN THE CENTRAL U.S. AND A SHORTWAVE RIDGE ALOFT BUILDS OVER THE REGION. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 800 PM EST SUNDAY... POOR FLYING CONDITIONS TONIGHT AND EARLY MONDAY. BKN-OVC MVFR CIGS WITH POCKETS OF IFR IN LIGHT RAIN/DRIZZLE ARE EXPECTED EARLY TONIGHT. FRONTAL PASSAGE TOWARD DAYBREAK MONDAY WILL BEGIN THE CLEARING PROCESS WITH WINDS BECOMING NORTHWESTERLY...DRY AIR ADVECTING INTO THE FORECAST AREA. A RETURN TO VFR IS EXPECTED FOR ALL RNK TERMINALS FOR MONDAY AFTERNOON. .EXTENDED FORECAST... ANOTHER POTENTIALLY POTENT SYSTEM THAT MAY IMPACT ALL OR PARTS OF THE REGION TUESDAY INTO WEDNESDAY WITH SUB- VFR DEVELOPING IN MOST LOCATIONS LATER TUESDAY INTO WEDNESDAY...WITH POST FRONTAL MVFR TO IFR POSSIBLE IN RAIN/SNOW ON THURSDAY. && .HYDROLOGY... AS OF 500 AM EST MONDAY... CONCERN FOR HAS BEEN POTENTIAL COMBINATION OF SNOW MELT AND HEAVY RAINFALL ACROSS THE GREENBRIER...UPPER JAMES RIVER BASINS WHERE UP TO TWO FEET OF SNOW HAS FALLEN DURING THE PAST COUPLE OF WEEKS. SOME MELTING HAS OCCURRED AND MORE IS EXPECTED TODAY AND TUESDAY. FORECAST RAIN AMOUNTS ON TUESDAY NIGHT AND WEDNESDAY MAY REACH 1.5 INCHES. THE COMBINATION OF SNOW MELT AND THIS MODERATE TO HEAVY RAINFALL MAY RESULT IN MINOR RISES ON AREA CREEKS AND STREAMS. MAJOR FLOODING IS NOT ANTICIPATED AT THIS TIME. THE NEXT WAVE OF HEAVIER PRECIPITATION SHOULD TRACK ACROSS THE PIEDMONT...WHERE THERE IS LITTLE TO NO SNOWPACK OF CONCERN. ONE OTHER ISSUE MIGHT BE POTENTIAL ICE JAMS ON LOCAL STREAMS AND RIVERS...GIVEN THE FACT THAT MUCH OF THE LAST THREE WEEKS HAVE BEEN WELL BELOW FREEZING...WITH MANY DAYS BELOW 20. THIS COULD RESULT IN MORE EXTENSIVE FLOODING IN CERTAIN SPOTS AND WILL NEED TO BE MONITORED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...MBS LONG TERM...DS AVIATION...PM HYDROLOGY...AMS/RAB

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