Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 011800 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 200 PM EDT FRI MAY 1 2015 .SYNOPSIS... AN UPPER LEVEL LOW PRESSURE WILL CONTINUE ITS PROGRESSION ACROSS THE AREA TODAY. HIGH PRESSURE WILL ARRIVE TO BRING WARMER WEATHER FOR EARLY NEXT WEEK. THE CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS WILL RETURN AS THE WEEK PROGRESSES. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1250 PM EDT FRIDAY... THE FIRST MAIN AREA OF PRECIPITATION IS BEGINNING TO DISSIPATE ACROSS SOUTHSIDE VIRGINIA AND NEIGHBORING SECTIONS OF NORTH CAROLINA. OUR ATTENTION FOR ADDITIONAL SHOWERS THIS AFTERNOON WILL BE CENTERED NEAR A LINE FROM LEWISBURG WV TO MT AIRY NC. SHOWERS ARE EXPECTED TO DEVELOP WITHIN THIS REGION EARLY THIS AFTERNOON...AND THEN GRADUALLY DRIFT EAST INTO THE EVENING HOURS...AND TREND TOWARDS LESS COVERAGE TOWARDS SUNSET. ISOLATED STORMS CANNOT BE RULED OUT WITHIN THE SHOWERS. TEMPERATURES HAVE BEEN SLOW TO RISE TODAY. HAVE TRENDED FORECAST HIGHS LOWER BY A FEW DEGREES ACROSS MUCH OF THE AREA. THE ONE EXCEPTION IS THE AREA BETWEEN LEWISBURG AND HOT SPRINGS...SOUTH INTO THE UPPER JAMES RIVER BASIN. THIS AREA HAS SEEN SOME BREAKS IN THE CLOUD COVER...ALLOWING FOR SOME WARMING. FOR THIS AREA...FORECAST HIGHS HAVE BEEN INCREASED A COUPLE OF DEGREES. NO OTHER MAJOR CHANGES AT THIS TIME. AS OF 930 AM EDT FRIDAY... NO MAJOR CHANGES HAVE BEEN MADE TO THE FORECAST FROM LATE THIS MORNING INTO THE EARLY AFTERNOON. WE ARE STILL EXPECTING A TREND TOWARDS THE CURRENTLY PRECIPITATION TO CONTINUE STREAMING TOWARD THE SOUTHWEST DURING THE REMAINDER OF THE AFTERNOON AND INTO THE EARLY AFTERNOON. FROM THE EARLY AFTERNOON THROUGH THE LATE AFTERNOON...A REDEVELOPMENT OF PRECIPITATION IS EXPECTED ACROSS THE CENTRAL TO WESTERN PORTIONS OF THE AREA ALONG A NORTH-SOUTH ORIENTATION. ENOUGH INSTABILITY MAY ALSO PROMPT SOME ISOLATED THUNDERSTORMS. AS OF 640 AM EDT FRIDAY... UPPER SYSTEM TRACKING OVER THE NW NC/SRN VA AREA THIS MORNING TO TRACK OUT OF THE AREA BY THIS EVENING. SHOWERS HAVE WEAKENED ACROSS PORTIONS OF THE NRN CWA WITH STRONGER COVERAGE FROM THE MARTINSVILLE/STUART VA AREA SOUTH INTO THE NC PIEDMONT. AS WE HEAD THROUGH THE MORNING THE MAIN COVERAGE WILL SHIFT EAST THEN ANOTHER AREA OF LIFT PIVOTS AREA OF SHOWERS BACK TOWARD THE WRN CWA...AND THIS PORTION OF THE FORECAST WAS NOT CHANGED. PREVIOUS DISCUSSION AT 400 AM... FOR THIS FIRST DAY OF MAY...EXPECT TO SEE SCATTERED TO NUMEROUS SHOWERS AS THE UPPER LOW OVER THE MOUNTAINS EARLY THIS MORNING SHIFTS EAST INTO THE PIEDMONT BY MIDDAY. THIS WILL PUT THE FAR SW VA/NW NC MTNS IN THE DRY POCKET...THOUGH NOT RAIN FREE WITH BEST LIFT AND UPPER SUPPORT KEEPING THE HIGHER THREAT OF RAIN FROM THE ALLEGHANY HIGHLANDS...EAST SOUTHEAST THROUGH ROANOKE/BLACKSBURG TO LYH/DAN. AS WE HEAD THROUGH THIS AFTERNOON...ANOTHER SPOKE OF ENERGY ON THE BACKSIDE OF THE DEPARTING UPPER LOW WILL SPIN MORE SHOWERS TOWARD THE HIGHLANDS INTO SE WV...SOUTH INTO THE NRV AND ROANOKE VALLEYS TO THE FOOTHILLS OF VA. ALL MODELS SEEM TO EVEN DEPICT THIS FAIRLY WELL. INSTABILITY TO BE LIMITED BUT AGAIN COLD POCKET ALOFT WITH ENOUGH LOW LVL INSTABILITY MAY EVEN ALLOW FOR SOME THUNDER ONCE AGAIN IN THE CORRIDOR FROM THE ALLEGHANYS TO SOUTHSIDE VA...AS GFS MUCAPE SHOWING 300-1000 J/KG AT 18Z...SO HAVE SLIGHT CHANCE T. COULD EVEN SEE SMALL HAIL AGAIN. HIGHS TODAY WILL BE STAY ABOUT 10 DEGREES COOLER THAN NORMAL WITH UPPER 50S TO AROUND 60 MOUNTAINS...TO LOWER TO MID 60S EAST. TONIGHT...THE GFS/ECMWF SHIFT MAIN RAIN THREAT OFFSHORE WITH POCKETS OF NRLY FLOW SHOWERS ACROSS THE MTNS/FOOTHILLS. THE NAM IS MORE AGGRESSIVE WITH COVERAGE BETWEEN THE BLUE RIDGE AND ALLEGHANYS. AM LEANING TOWARD DRIER SOLUTION BUT KEPT SLIGHT TO LOW CHANCE POPS THIS EVENING IN THE MTNS TO BLUE RIDGE SIMILAR TO NAM LOCATION.. THEN OVERNIGHT CLEARING TAKES PLACE WITH NW FLOW ALOFT BRINGING DRIER AIR IN WITH SFC HIGH MOVING INTO THE OHIO AND TENNESSEE VALLEYS BY DAWN SATURDAY. LOWS EXPECTED TO BE CLOSER TO NORMAL WITH LOWER TO MID 40S MTNS TO UPPER 40S EAST. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... AS OF 330 AM EDT FRIDAY... LOOKING TO SATURDAY...TEMPERATURES WILL BE AT LEAST 10 DEGREES WARMER OVER THOSE OBSERVED ON FRIDAY AS UPPER LEVEL TROUGHING MOVES FURTHER AWAY FROM THE MID ATLANTIC...WHILE HIGH PRESSURE IN THE LOW LEVELS WILL MAKE FOR INCREASED SUNSHINE AND THEREFORE STRONGER HEATING. MODELS STILL HINTING AT THE POSSIBILITY OF A FEW SHOWERS ACROSS THE PIEDMONT...MAYBE EVEN A SHORT LIVED THUNDERSTORM OR TWO DURING LATE AFTERNOON...AS A WEAK UPPER LEVEL DISTURBANCE MOVES ACROSS THE AREA. OTHERWISE...EXPECT LIGHT NORTHERLY WINDS THROUGH THE DAY...WITH AFTERNOON HIGH TEMPERATURES REACHING INTO THE UPPER 60S ACROSS THE MOUNTAINS...AND THE LOW TO MID 70S FURTHER EAST. UPPER LEVEL RIDGING ACROSS THE CENTRAL PART OF THE NATION WILL DRIFT EAST ON SUNDAY AND MONDAY...RESULTING IN INCREASING 500MB HEIGHTS. WILL ALSO SEE HIGH PRESSURE IN THE LOW LEVELS PASS EAST OF THE MOUNTAINS SATURDAY NIGHT...BRINGING A RETURN OF SOUTHWESTERLY WINDFLOW TO OUR AREA. BOTH WILL SUPPORT A CONTINUED WARMUP FOR THE MID ATLANTIC THAT WILL PERSIST INTO THE MIDDLE OF NEXT WEEK. SUNDAY AFTERNOON HIGHS WILL REACH INTO THE 70S MOST LOCATIONS...WITH UPPER 60S MORE LIKELY FOR THE HIGHER ELEVATIONS...AND MONDAY WILL BE A FEW DEGREES WARMER STILL...WITH SPOTS ACROSS THE SOUTHSIDE LIKELY TOUCHING 80 DEGREES. MAY SEE A SHOWER OR TWO DEVELOP ACROSS THE MOUNTAINS EITHER DAY WITH DAYTIME HEATING...BUT DO NOT EXPECT ANY ORGANIZED DISTURBANCES PASSING ACROSS OUR AREA. WARMER OVERNIGHTS CAN BE EXPECTED AS WELL. SATURDAY NIGHT LOW TEMPERATURES WILL FALL INTO THE 40S AREAWIDE...WITH LOWS WARMING A FEW DEGREES EACH NIGHT SUCH THAT MOST AREAS CAN EXPECT 50S FOR LOWS ON MONDAY NIGHT. && .LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 1230 PM EDT THURSDAY... UPPER LEVEL RIDGING WILL CONTINUE ACROSS THE REGION DURING THE MAJORITY OF THIS PORTION OF THE FORECAST. AN UPPER LOW MOVING EASTWARD THROUGH CANADA WILL WEAKEN THE RIDGE A BIT WEDNESDAY INTO THURSDAY...SHIFTING A BACKDOOR FRONT TOWARD OUR REGION. WHILE ALL OF THIS IS OCCURRING...AN ELONGATED TROUGH/UPPER LOW WILL BE DEVELOPING ACROSS THE CENTRAL PART OF THE COUNTRY. WE ARE ANTICIPATING PROGRESSIVELY MILDER TEMPERATURES EACH DAY WITHIN THIS REGIME. FOR PRECIPITATION...THE CENTER OF THE SURFACE HIGH WILL JUST BE SHIFTING EAST OF THE AREA ON MONDAY. THIS WILL LIMIT THE DEGREE OF RETURN MOISTURE INTO THE AREA TO THE NORTHERN MOUNTAINS OF NORTH CAROLINA. IT IS HERE WHERE ISOLATED SHOWERS WILL BE FORECAST FOR THE AFTERNOON. FROM TUESDAY INTO THURSDAY...COVERAGE OF SHOWERS AND STORMS WILL BE INCREASING...ESPECIALLY IN THE WEST...WITH THE APPROACH...AND POTENTIAL ARRIVAL...OF THE BACKDOOR FRONT. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AS OF 140 PM EDT FRIDAY... FORECAST CONFIDENCE IS MODERATE TO HIGH THROUGH SATURDAY. MIX OF MVFR AND LOW END VFR CIGS PREVAIL ACROSS THE REGION THIS AFTERNOON AS THE AREA AS AN AREA OF UPPER LEVEL LOW PRESSURE CROSS THE REGION. SHOWERS HAD STARTED TO DECREASE IN COVERAGE UNTIL RECENTLY. NOW THE FOCUS FOR NEW DEVELOPMENT WILL BE ALONG A KLWB- KBCB LINE...AND THEN POINTS EAST AS THE CONVECTION TRANSITIONS EASTWARD...FOLLOWING THE TRACK OF THE UPPER LOW. BRIEF...ISOLATED IFR CONDITIONS WILL BE POSSIBLE UNDER THE HEAVIER SHOWERS AND STORMS THAT DEVELOP. OVERNIGHT...CLOUDS WILL DECREASE IN COVERAGE AS DRIER AIR STARTS TO WORK ITS WAY INTO THE AREA...AND PRECIPITATION WILL DECREASE IN COVERAGE THROUGH THE EVENING HOURS. LINGERING BOUNDARY LAYER MOISTURE MAY DEVELOP INTO SOME PATCHY FOG IN THE RIVER AND MOUNTAIN VALLEYS AS WINDS TREND LIGHTER. BETWEEN KBLF-KLWB...A SHALLOW IFR CIG MAY DEVELOP AS LIGHT NORTHWEST FLOW GENERATES A SMALL UPSLOPE COMPONENT IN THIS AREA. ON SATURDAY...ANY SUB-VFR OVERNIGHT CONDITIONS WILL TRANSITION FAIRLY QUICKLY TO VFR AFTER SUNRISE. THE VISIBILITY SENSOR AT THE ASOS AT KBLF CONTINUES TO MALFUNCTION. WILL CONTINUE WITH AMD NOT SKED APPENDED TO ITS TAF. FORECAST CONFIDENCE IS HIGH SATURDAY AFTERNOON THROUGH MONDAY NIGHT. OTHER THAN SOME PATCHY LATE NIGHT/EARLY MORNING RIVER VALLEY FOG IN THE TYPICAL LOCATIONS...VFR CONDITIONS ARE EXPECTED THROUGH MONDAY NIGHT. FORECAST CONFIDENCE TUESDAY THROUGH WEDNESDAY IS MODERATE. LOOK FOR AN INCREASING AMOUNT OF SHOWERS AND LOWER BASED CLOUDS TUESDAY AND WEDNESDAY AS LOW LEVEL MOISTURE FLOW INCREASES ACROSS THE AREA...AND A BACKDOOR FRONT DRIFTS SOUTH TOWARD OR INTO OUR AREA. && .EQUIPMENT... AS OF 1255 PM EDT FRIDAY... THE VISIBILITY SENSOR AT THE BLUEFIELD...KBLF...ASOS MAY ALTERNATE BETWEEN AVAILABLE AND UNAVAILABLE UNTIL SUCH TIME APPROPRIATE CORRECTIVE MEASURES CAN BE COMPLETED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS/PW/WP NEAR TERM...DS/WP SHORT TERM...NF LONG TERM...DS AVIATION...DS EQUIPMENT...DS

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