Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 011922 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 322 PM EDT FRI MAY 1 2015 .SYNOPSIS...
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AN UPPER LEVEL LOW PRESSURE SYSTEM WILL PROGRESS EASTWARD...OUT OF THE REGION TONIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEKEND AND BE POSITIONED ACROSS OUR REGION INTO MUCH OF NEXT WEEK. OUR NEXT BEST CHANCE OF PRECIPITATION WILL COME DURING THE MIDDLE OF NEXT WEEK WHEN A BACKDOOR COLD FRONT APPROACHES OUR AREA.
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&& .NEAR TERM /THROUGH SATURDAY/...
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AS OF 300 PM EDT FRIDAY... AN AREA OF SHOWERS WITH A FEW THUNDERSTORMS CONTINUES TO EXPAND IN COVERAGE BETWEEN ROUGHLY HOT SPRINGS AND BLACKSBURG VA. THE PRECIPITATION WAS EXPANDING TOWARDS THE S-SW. HEADING INTO THIS EVENING...THE REGION OF PRECIPITATION WILL GRADUALLY MAKE PROGRESS EASTWARD...IN PACE WITH THE PROGRESSION OF THE RESPONSIBLE UPPER LEVEL LOW PRESSURE SYSTEM. COVERAGE WILL START TO DECREASE AT SUNSET...WITH THE LAST SHOWERS EXITING THE AREA OR DISSIPATING AROUND 11PM BETWEEN DANVILLE AND LYNCHBURG. CLOUD COVER WILL BE ON THE DECREASE THE REMAINDER OF THE NIGHT. PATCHY LIGHT RIVER VALLEY FOG WILL BE POSSIBLE...AND ALSO IN VALLEYS THAT RECEIVED PRECIPITATION THIS AFTERNOON OR EVENING. LOW TEMPERATURES WILL RANGE FROM AROUND 40 TO THE MID 40S ACROSS THE MOUNTAINS...WITH MID 40S TO UPPER 40S ACROSS THE PIEDMONT. ON SATURDAY...HIGH PRESSURE WILL START TO WORK ITS WAY INTO THE REGION FROM THE WEST. ONE LATE SHORTWAVE TROUGH ROUNDING THE BACKSIDE OF THE DEPARTING UPPER LOW IS EXPECTED TO MOVE SOUTH THROUGH CENTRAL VIRGINIA AND NORTH CAROLINA TOMORROW AFTERNOON. THIS FEATURE PASSING AT THE TIME OF PEAK HEATING MAY HELP TO GENERATE SOME ISOLATED SHOWERS...GENERALLY ALONG AND EAST OF A LEXINGTON VA TO REIDSVILLE NORTH CAROLINA LINE. THANKS TO BUILDING HEIGHTS AND LESS CLOUD COVER...ANTICIPATE A MILDER DAY ON SATURDAY AS COMPARED TO TODAY. HIGHS ACROSS THE MOUNTAINS WILL RANGE FROM THE MID 60S TO NEAR 70 DEGREES...WITH LOW TO MID 70S ACROSS THE PIEDMONT.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
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AS OF 315 PM EDT FRIDAY... 500 MB HEIGHTS GRADUALLY RISE SATURDAY NIGHT AND SUNDAY AS THE PATTERN BECOMES MORE ZONAL. BUFKIT DATA FOR SUNDAY IN THE SOUTHWEST COUNTY WARNING AREA SHOWED A LARGE ENOUGH LOW LEVEL LAPSE RATE AND A LAYER OF MOISTURE THAT WOULD SUPPORT SHOWERS ISOLATED THUNDERSTORMS. HOWEVER...THERE WILL ONLY BE MINIMAL LIFT FROM ANY VORTICITY SO COVERAGE WILL BE CONFINED TO AREAS WITH THE BEST HEATING AND INSTABILITY. AIR MASS WARMS THROUGH THE PERIOD AND WILL BE CLOSE TO +10 TO +12 VALUES AT 850 MB BY THE END OF THE DAY ON MONDAY. THIS WILL PUT MAXIMUM TEMPERATURES JUST ABOVE NORMAL MONDAY. HIGH PRESSURE WILL BE OVER THE AREA SATURDAY NIGHT AND SUNDAY.
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&& .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
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AS OF 125 PM EDT FRIDAY... LONG WAVE PATTERN ADVERTISED BY MODELS SHOWED TROFING IN THE WESTERN UNITED STATES AND A BROAD SOUTHEAST U.S. RIDGE. A SURFACE COLD FRONT THE THE NORTHERN STREAM WILL BE OVER THE GREAT LAKES ON MONDAY AND WILL PUSH SOUTH AS A BACKDOOR FRONT OVER THE MID ATLANTIC REGION TUESDAY AND WEDNESDAY. QUESTIONABLE HOW FAR SOUTH THIS BOUNDARY GETS HEADING INTO A LARGE RIDGE OVER THE SOUTHEAST. BEST PROBABILITY OF PRECIPITATION WILL BE IN THE VICINITY OF THIS BOUNDARY. OTHERWISE THE CHANCE WILL BE LIMITED TO AIRMASS TYPE THUNDERSTORMS...MAINLY IN THE MOUNTAINS EACH AFTERNOON AND EVENING. MAXIMUM/MINIMUM TEMPERATURES WILL REMAIN 5 TO 15 DEGREES ABOVE NORMAL TUESDAY THROUGH FRIDAY.
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&& .AVIATION /19Z 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 NEAR TERM...DS SHORT TERM...AMS LONG TERM...AMS AVIATION...DS EQUIPMENT...DS

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