Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 300112 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 912 PM EDT SUN MAR 29 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST OVERNIGHT BEFORE PASSING ACROSS THE AREA MONDAY MORNING. A SECOND COLD FRONT AND ASSOCIATED CLIPPER SYSTEM WILL PASS ACROSS THE REGION ON TUESDAY...FOLLOWED BY HIGH PRESSURE FOR THE MIDDLE OF THE WEEK. MOISTURE AHEAD OF ANOTHER STRONGER COLD FRONT WILL INCREASE BY THE END OF THE WEEK BRINGING THE NEXT CHANCE FOR SHOWERS AND POSSIBLE STORMS ON FRIDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 845 PM EDT SUNDAY... MAIN AXIS OF DEEPER PRE-FRONTAL MOISTURE REMAINS JUST WEST OF THE OHIO RIVER THIS EVENING WITH LOTS OF VERY DRY AIR STILL OVER THE AREA IN ADVANCE OF THIS BOUNDARY. THIS SEEN VIA THE LINGERING LOW PWAT AND MID LEVEL DRYNESS SEEN OFF THE EVENING RNK SOUNDING AS WELL AS THE CONTINUED LOW DEWPOINTS AT THE SURFACE PER LATEST OBS. MOST SOLUTIONS INCLUDING THE LATEST HRRR AND HIRES-ARW DO BRING SOME PRECIP INTO THE FAR NW SHORTLY AFTER MIDNIGHT...THEN SOUTH AND EAST TO THE BLUE RIDGE WITH BEST LIFT/MOISTURE WORKING DOWN THE WESTERN SLOPES INTO THE NW NC RIDGES BEFORE DAYBREAK. SHOWER BAND MAY THEN TEND TO JUMP EAST OF THE MOUNTAINS LATE OR EARLY MONDAY BUT IFFY GIVEN DEEP WESTERLY FLOW ALOFT SEEN OFF EVENING RAOBS. SINCE GUIDANCE REMAINS TOO FAST WITH PRECIP INTO THE DRY AIR FROM EARLIER...SLOWED DOWN POPS AGAIN OVERNIGHT IN THE WEST WHILE INCREASING SOME OVER THE SW TOWARD DAYBREAK WHERE RUNNING WITH BRIEF CAT/LIKELY POPS FOR LOW QPF. LEFT IN SOME LOW POPS OUT EAST AS WELL BUT DOUBTFUL AS TO HOW FAR EAST OF THE BLUE RIDGE MUCH MORE THAN SPRINKLES MAKE IT OVERNIGHT. VERY DRY AIR AND TEMPS COOLING INTO THE 30S COULD SUPPORT A BIT OF SLEET WEST AT THE ONSET SO ADDED WHILE KEEPING THE SNOW MENTION AT ELEVATION ACROSS THE NW WHERE COULD SEE SOME LIGHT ACCUMULATION. OTRW LOWERED TEMPS EARLY OVER THE WEST FOR SOME WET BULB COOLING AT THE ONSET BEFORE READINGS RISE LATE AS MIXING PICKS UP JUST AHEAD OF THE FRONT BY DAWN. PREVIOUS DISCUSSION AS OF 329 PM EDT SUNDAY... 1030 MB SFC HIGH PRESSURE CENTERED OVER SOUTH CAROLINA THIS AFTERNOON WILL MOVE SOUTHEAST THIS EVENING INTO TONIGHT. LOW PRESSURE OVER THE GREAT LAKES WITH A TRAILING COLD FRONT WILL MOVE EAST TONIGHT INTO MONDAY. CLOUD COVER WILL SPREAD EAST ACROSS THE AREA THIS EVENING INTO TONIGHT IN ADVANCE OF AN APPROACHING COLD FRONT. MODELS CONTINUE TO TREND SLOWER WITH THE ARRIVAL OF THE PRECIPITATION IN THE REGION. WITH A DRY AIRMASS IN PLACE AS NOTED BY PWAT AT 0.05 ON THIS MORNING 12Z RNK SOUNDING...SLOWED OUR ARRIVAL TIME A LITTLE. DESPITE THE DRY AIR...MOISTURE AND LIFT WILL INCREASE LATE TONIGHT INTO MONDAY MORNING. MODELS ARE STILL SHOWING PRECIPITABLE WATER RISING ABOVE 0.50 INCH. FOR TONIGHT POPS USED A BLEND OF HIRESW-ARW EAST...RAP AND NAM...THEN LEANED TOWARDS THE NAM AND GFS BLEND MONDAY. BELIEVE THER IS ENOUGH COLD AIR TO ALLOW RAIN SHOWERS TO BECOME MIXED WITH SNOW SHOWERS IN THE HIGHER ELEVATIONS. A LIGHT SNOW ACCUMULATION LESS THAN A INCH MAY BE POSSIBLE IN THE NORTHWEST HIGHEST ELEVATIONS. WPC HAS PAINTED A SMALL AREA OF SNOW IN THE WINTER WEATHER DAY 1 OUTLOOK JUST TO OUR NORTH. WINDS PICK UP AHEAD OF THE COLD FRONT BUT BUFKIT SHOWED STRONGEST WINDS AHEAD OF THE FRONT JUST ABOVE THE SURFACE AND REMAINING ABOVE THE INVERSION. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE LOWER 30S IN THE NORTHWEST MOUNTAINS TO AROUND 40 DEGREES IN THE PIEDMONT. A COLD FRONT PASSING ACROSS THE AREA EARLY MONDAY...WILL TRIGGER SHOWERS AS IT MOVES EAST ACROSS THE PIEDMONT. SHOWERS WILL DIMINISH QUICKLY BEHIND THE FRONT AS WINDS SHIFT WEST TO NORTHWEST AS HIGH PRESSURE BUILDS IN FROM THE CENTRAL PLAINS. HIGH TEMPERATURES MONDAY WILL RANGE FROM THE UPPER 40S IN SOUTHEAST WEST VIRGINIA TO THE LOWER TO MID 60S ACROSS THE PIEDMONT. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 305 PM EDT SUNDAY... NEXT SHORTWAVE/CLIPPER SLIDES FROM NRN IL MONDAY EVENING INTO CENTRAL VA BY TUESDAY AFTERNOON. MODELS ARE SIMILAR IN KEEPING MAIN THREAT OF SHOWERS NORTH OF INTERSTATE 64...SO NOT GOING WITH POPS ANY HIGHER THAN 25. A LITTLE LEFTOVER COLD AIR TUESDAY MORNING COULD ALLOW FOR SOME WINTRY MIX NORTH OF LEWISBURG AND HOT SPRINGS...BUT OVERALL DRY. WE WILL SEE HIGH PRESSURE WORK EASTWARD ACROSS THE MID ATLANTIC WEDNESDAY WITH SE FLOW DEVELOPING LATE IN THE DAY. TEMPS WILL BE AT AND ABOVE SEASONAL NORMS. THE WEST FLOW TUESDAY AHEAD OF THE CLIPPER SHOULD ENHANCE TEMPS ACROSS THE PIEDMONT BARRING ANY EXTENSIVE CLOUD COVER...WITH NEAR 70 POSSIBLE FROM DANVILLE/MARTINSVILLE SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 200 PM EDT SUNDAY... MODELS CONTINUE TO VARY ON SPEED/AMPLIFICATION OF NEXT SYSTEM AFFECTING OUR AREA THE END OF THE WEEK...THOUGH IN DECENT AGREEMENT THAT THERE WILL BE A THREAT OF SHOWERS THU-EARLY SATURDAY...WITH FRIDAY LOOKING THE MOST UNSETTLED. WARM ADVECTION PATTERN WILL KICK IN ONCE THE HIGH MOVES OFF THE COAST WEDNESDAY NIGHT...THOUGH AM THINKING ENOUGH SE FLOW AND IN SITU WEDGE MAY HOLD TEMPS DOWN BRIEFLY BEFORE STRONGER LLJ MOVES ACROSS THE MTNS. EXPECT A CHANCE OF RAIN/RAIN SHOWERS BY THURSDAY WITH BETTER CONVERGENCE WEST OF THE MTNS...WITH SOME OVERRUNNING INTO THE SRN CWA. THURSDAY NIGHT INTO FRIDAY FRONTAL BOUNDARY WORKS SLOWLY SE INTO PA- KY LINE WITH MAIN SFC LOW WELL INTO CANADA. ANOTHER WAVE OR TWO OF LOW PRESSURE IS EXPECTED TO FORM ALONG THE FRONT FRIDAY AFTERNOON/EVENING. MODELS SHOW INSTABILITY IN THE WARM SECTOR AND ADDED SOME THUNDER IN MOST PLACES FRIDAY. STILL NOT GOING TO HAVE LIKELY POPS YET...AS MODELS ARE NOT CONSISTENT WITH POTENTIAL FOR SEEING A BREAK IN THE ACTION IN BETWEEN WAVES. AS WE HEAD INTO FRIDAY NIGHT-SATURDAY...THE ECMWF KICKS THE FRONT EAST FAST BY ABOUT 5-8 HOURS...WITH GFS SLOWLY EDGING IT SOUTHWARD WITH WEAKER LOW. WILL MAINTAIN SHOWER CHANCES WITH HIGHER POPS FRIDAY NIGHT BEFORE WE START TO SEE DRYING BY SAT AFTERNOON. A BRIEF SHOT OF COOLER/DRIER AIR...THOUGH CLOSER TO NORMAL FOLLOWS THIS FRONT SAT NIGHT-SUNDAY. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... AS OF 650 PM EDT SUNDAY... HIGH PRESSURE TO THE SOUTH OF THE REGION WILL GIVE WAY TO A COLD FRONT THAT WILL APPROACH FROM THE NORTHWEST OVERNIGHT BEFORE PASSING THROUGH THE AREA MONDAY MORNING. MOISTURE WELL IN ADVANCE OF THE FRONT WILL OVERSPREAD THE TAF SITES FROM THE NORTHWEST BY MIDNIGHT...WITH DEEPER MOISTURE AND PRECIP CLOSER TO THE FRONT ARRIVING DURING THE EARLY MORNING HOURS OF MONDAY. THIS SHOULD BRING A FEW HOURS OF MVFR TO LOCATIONS FROM KBCB WESTWARD INTO SE WEST VA AFTER MIDNIGHT AND PERHAPS AS FAR EAST AS KROA BY DAYBREAK MONDAY. LIGHT RAINFALL MAY REDUCE VSBYS TO LOW END VFR AT TIMES BY EARLY MONDAY WITH OCNL MVFR POSSIBLE AROUND KBLF. GIVEN THE VERY DRY AIR...SOME SLEET MAY ALSO OCCUR ACROSS THE MOUNTAINS AT THE ONSET BUT SHOULD BE BRIEF AND ON THE LIGHT SIDE. CIGS SHOULD GRADUALLY IMPROVE TO MOSTLY VFR HEADING INTO MONDAY AFTERNOON AS MUCH DRIER AIR ALOFT WORKS IN BEHIND THE FRONT. SOUTHWEST WINDS AT 10-15 KTS WILL GRADUALLY BECOME MORE WESTERLY BY EARLY MONDAY AND THEN SHIFT TO THE NW BEHIND THE FRONT MONDAY AFTERNOON WHEN GUSTS TO 25-30 KTS MAY OCCUR OVER THE WEST. MEDIUM TO HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS DURING THE TAF PERIOD. EXTENDED AVIATION FORECAST... THERE IS ALSO POTENTIAL FOR STRONG GUSTY WINDS TO CONTINUE MONDAY NIGHT BEHIND THE FRONT...AND AGAIN ON TUESDAY AS ANOTHER CLIPPER SLIDES ACROSS FROM THE NORTHWEST. WEAK HIGH PRESSURE SHOULD MAINTAIN MAINLY VFR CONDITIONS TUESDAY INTO WEDNESDAY WITH ONLY LINGERING MOUNTAIN UPSLOPE DRIVEN MVFR CIGS AND SPOTTY SHOWERS ON TUESDAY. ON THURSDAY...AS A WARM FRONT LIFTS NORTH ACROSS THE REGION WITH THE POSSIBILITY OF SUB-VFR CONDITIONS . MOISTURE WILL INCREASE AHEAD OF A STRONGER COLD FRONT FRIDAY WITH MVFR/IFR CONDITIONS POSSIBLE IN CONVECTION. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH/KK NEAR TERM...JH/KK SHORT TERM...WP LONG TERM...WP AVIATION...AMS/JH/KK

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