Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 241858 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 258 PM EDT TUE MAR 24 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN WEDGED ALONG THE EASTERN SLOPES OF THE APPALACHIANS TODAY INTO TONIGHT. A WARM FRONT WILL LIFT SLOWLY NORTH INTO THE AREA BY WEDNESDAY AHEAD OF A STRONG COLD FRONT APPROACHING FROM THE WEST. THE FRONT CROSS THE REGION LATER THURSDAY BRINGING MORE WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM EDT TUESDAY... SATELLITE IMAGERY INDICATES A MIXTURE OF CLOUDS AND SUNSHINE THIS MORNING...WITH TEMPERATURES STARTING TO SPIKE UPWARD IN AREAS WHERE PROLONGED SUNSHINE IS REACHING THE SURFACE. NOTICING THE BACK EDGE OF CLOUDS ENTERING THE MOUNTAIN EMPIRE...SO LOOKS LIKE WE WILL SEE AN AREA OF MORE PROLONGED CLEARING IN THE WEST. HAVE THEREFORE ADJUSTED AFTERNOON HIGHS A FEW DEGREES UPWARD ACROSS FOR THE INTERSTATE 77 CORRIDOR WESTWARD...AND THEN TAPERED THE RISE IN TEMPERATURES UPWARD TO A LESSER EXTENT FURTHER EAST TO THE BLUE RIDGE. REGARDLESS...TODAY IS ANOTHER ONE OF THOSE DAYS WHERE YOU ARE BETTER OFF DRESSING IN LAYERS WHICH CAN BE ADDED OR REMOVED AS THE SUN MOVES IN AND OUT FROM BEHIND THE CLOUDS. RAPID UPDATE WEATHER MODELS HAVE BACKED OFF ON THE TIMING OF OUR NEXT UPPER LEVEL DISTURBANCE. HAVE THEREFORE REMOVED ANY RAIN CHANCES FOR THE MORNING...AND INSTEAD WILL SEE RAIN CHANCES INCREASE DURING LATE AFTERNOON AS THE DISTURBANCE ENTERS THE AREA. BOUNDARY TO OUR SOUTH STARTS TO LIFT BACK NORTH TONIGHT AS A WARM FRONT WITH DEEPENING SOUTHERLY FLOW AROUND AND OVER THE LINGERING LOW LEVEL COLD POOL ASSOCIATED WITH HIGH PRESSURE TO OUR EAST. THIS ALONG WITH FAINT IMPULSES RIDING IN ALOFT JUST NORTH OF THE FRONT MAY ALLOW FOR BETTER COVERAGE OF -RA WITHIN THE WEDGE WITH MORE SHOWERY NATURE SW AS WELL AS THE WESTERN SLOPES. MAY EVEN BE SOME DRIZZLE AROUND BLUE RIDGE EAST LATE PENDING DEGREE OF SATURATION WITHIN THE CAD. THUS KEEPING OVERALL DECENT CHANCE POPS WITH ONLY A FEW POCKETS OF RAIN/SNOW MIX AT THE HIGHEST ELEVATIONS ACROSS THE EXTREME NORTH. SHOULD SEE TEMPS STEADY OUT AFTER MIDNIGHT AND POSSIBLY RISE OVER THE SW GIVEN INCREASING WARM ADVECTION. EXPECT COLDEST READINGS IN THE NORTH/EAST UNDER THE DEEPER COLD POOL WITH LOWS IN THE 30S...WHILE SPOTS FROM ALONG THE BLUE RIDGE WEST ONLY FALL INTO THE 40S FOR THE MOST PART. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 345 AM EDT MONDAY... WEDNESDAY WILL START WITH A CONTINUING WEDGE SITUATION AS HIGH PRESSURE OVER THE NORTHEAST EXTENDS DOWN THE EASTERN SEABOARD. THIS WILL KEEP A SHALLOW LAYER OF COOL AIR AT THE SURFACE EAST OF THE BLUE RIDGE AS A SERIES OF LOW PRESSURE SYSTEMS MOVE THROUGH THE OHIO VALLEY TO OUR WEST. THIS WILL ALLOW FOR WARM AND MOIST AIR TO RUN UP OVER THE WEDGE WITH THE ISENTROPIC LIFT AND SOUTHEASTERLY UPSLOPE WINDS EAST OF THE BLUE RIDGE GENERATING SOME LIGHT PRECIPITATION INTO WEDNESDAY NIGHT. THE WEDGE WILL WEAKEN AND GIVE WAY EARLY WEDNESDAY NIGHT WITH TEMPERATURES SLOWLY RISING AFTER MIDNIGHT. WITH THE WEDGE NO LONGER KEEPING THE BOUNDARY LAYER COOL TEMPERATURES ON THURSDAY WILL RISE INTO THE 60S AND 70S AHEAD OF AN APPROACHING COLD FRONT. THE WARM AND MOIST CONDITIONS WILL CREATE ENOUGH INSTABILITY FOR A CHANCE OF THUNDERSTORMS AHEAD OF THE FRONT THURSDAY AFTERNOON INTO THURSDAY NIGHT. THE MODELS DIFFER A BIT ON TIMING THE FRONTAL PASSAGE AND THE TREND SEEMS TO BE FOR SLOWER MOVEMENT...BUT THE FRONT LOOKS TO BE PUSHING OFF TO OUR EAST BY FRIDAY MORNING. MUCH COLDER AIR WILL MOVE IN BEHIND THE FRONT AND BRING AN EARLY SPRING COLD SNAP WITH TEMPERATURES WELL BELOW NORMAL INTO THE WEEKEND. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... AS OF 245 PM EDT MONDAY... RETURN TO WINTER DURING THIS PERIOD. SIGNIFICANTLY COLDER TEMPERATURES WILL ADVECT INTO THE REGION FROM THE NORTHWEST. 850MB TEMPS WILL PLUNGE TO WELL BELOW ZERO...BOTTOMING OUT AROUND -16C ACROSS THE MOUNTAINS BY 12Z SAT. THE COLD ADVECTION SIGNAL/AND POCKET OF COLD AIR ASSOCIATED WITH THIS SYSTEM...-22C NEAR PIT...APPEARS SIMILAR TO SEVERAL EVENTS WE SAW IN FEBRUARY...SO NEEDLESS TO SAY IT IS GOING TO BE A RUDE AWAKENING COMPARED TO RECENT DAYS. THE WEEKEND SHOULD BE DRY WITH MUCH BELOW NORMAL TEMPERATURES AS THE CANADIAN HIGH SETTLES OVER THE REGION BY EARLY SUN...THEN A SLIGHT REINFORCING SURGE IS NOTED FOR LATE IN THE WEEKEND INTO MONDAY. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... AS OF 230 PM EDT TUESDAY... HIGH PRESSURE REMAINS SITUATED OVER THE DELMARVA THIS AFTERNOON... MAINTAINING A LIGHT EAST TO SOUTHEASTERLY FLOW GENERALLY EAST OF THE INTERSTATE 77 CORRIDOR. FURTHER WEST...OBSERVING SOUTHWESTERLY WIND FLOW WHERE HIGH PRESSURE IS LESS INFLUENTIAL. SATELLITE INDICATES A CU FIELD WEST OF THE BLUE RIDGE WITH VFR BASES GENERALLY IN THE 5KFT TO 7KFT. RADAR INDICATES A FEW SHOWERS ASSOCIATED WITH AN APPROACHING UPPER LEVEL DISTURBANCE PASSING EAST ACROSS WEST VIRGINIA. THIS EVENING...CLOUD COVER WILL CONTINUE TO INCREASE AS THE DISTURBANCE APPROACHES. MAY SEE A FEW SHOWERS ACROSS THE MOUNTAINS BEFORE SUNSET...BUT MORE WIDESPREAD LIGHT RAIN WILL ENTER THE AREA BETWEEN SUNSET AND MIDNIGHT. WHILE RAINFALL IS EXPECTED TO BE LIGHT AND RESULT IN ONLY SPORADIC/MODEST REDUCTIONS IN VISIBILITY... DO EXPECT THE ADDED MOISTURE TO ENHANCE THE HIGH PRESSURE WEDGED AGAINST THE MOUNTAINS...RESULTING IN LOWERING CEILINGS THROUGH THE NIGHT. EXPECT VFR CONDITIONS TO PERSIST MOST LOCATIONS THROUGH 05Z/06Z...BEFORE CEILINGS BEGIN TO LOWER TO MVFR...AND EVENTUALLY IFR TOWARD DAWN WEDNESDAY FOR SPOTS ACROSS THE MOUNTAINS. DRIER AIR HUGGING THE SURFACE EAST OF THE BLUE RIDGE SHOULD KEEP CEILINGS TO LOW END MVFR. A TRAIN OF WEAK DISTURBANCES WILL CONTINUE TO PUSH ACROSS THE AREA ON WEDNESDAY...KEEPING THE HIGH PRESSURE WEDGE LOCKED IN...WITH SOUTH TO SOUTHEASTERLY WIND FLOW AND ONLY A GRADUAL IMPROVEMENT OF CEILINGS INTO THE AFTERNOON. SOUTHWEST WINDS ARE EXPECTED TO INCREASE AHEAD OF AN APPROACHING COLD FRONT LATE WEDNESDAY NIGHT...ALLOWING FOR IMPROVEMENT TO VFR INTO THURSDAY. THIS COLD FRONT IS EXPECTED TO MOVE INTO OUR AREA THURSDAY EVENING...WITH SHOWERS AND THE POTENTIAL FOR A FEW THUNDERSTORMS. DO SEE SOME POTENTIAL FOR FRONTAL SLOWDOWN AHEAD OF ANOTHER DISTURBANCE APPROACHING FROM THE WEST FRIDAY...RESULTING IN LINGERING RAIN/MOUNTAIN SNOW SHOWERS AND SUB VFR CEILINGS OVER THE WEST. VFR RETURNS TO AREAS EAST OF THE BLUE RIDGE SATURDAY WHILE UPSLOPE DRIVEN MVFR LOW CLOUDS LIKELY PERSIST MOUNTAINS UNDER CONTINUED GUSTY NORTHWEST WINDS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/NF NEAR TERM...JH/NF SHORT TERM...MBS LONG TERM...AMS/MBS/RAB AVIATION...JH/NF

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