Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 060500 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1200 AM EST SAT FEB 6 2016 .SYNOPSIS... HIGH PRESSURE WILL BUILD ACROSS THE AREA FROM THE WEST TONIGHT AND REMAIN OVER THE REGION INTO SATURDAY NIGHT. A STORM SYSTEM DEVELOPING OFF THE SOUTHEAST COAST SHOULD PASS WELL TO THE SOUTH AND EAST LATER SATURDAY NIGHT INTO SUNDAY NIGHT. ANOTHER COMPLEX AREA OF LOW PRESSURE WILL ARRIVE FROM THE NORTHWEST MONDAY BRINGING COLDER TEMPERATURES ALONG WITH THE THREAT OF MORE WINTRY PRECIPITATION INTO MIDWEEK. && .NEAR TERM /THROUGH SATURDAY/... AS OF 920 PM EST FRIDAY... UPDATED GRIDS STAYED FAIRLY CONSISTENT WITH THE PREVIOUS...ONLY CHANGED OVER NIGHT MINIMUM TEMPERATURE SLIGHTLY COOLER DUE TO EXPECTED RADIATIONAL COOLING WITH A TYPICAL DIURNAL TREND. THERE ARE SOME HIGH THIN CLOUDS EXPECTED IN THE NORTH AND NORTH WEST REGION OF THE FORECAST AREA. WINDS WILL STAY LIGHT FOR MOST OF THE NIGHT WITH CALM CONDITIONS DOMINATING UNTIL JUST AFTER SUNRISE. PREVIOUS AFD... SHORTWAVE RIDGE AXIS WILL CROSS THE REGION TONIGHT ALLOWING FOR DEEPENING SW FLOW ALOFT INTO SATURDAY AHEAD OF THE NEXT UPPER LOW/TROUGH EJECTING EAST OUT OF THE SOUTHERN PLAINS. THIS SHOULD BEGIN TO TAP HIGH LEVEL MOISTURE AHEAD OF THIS FEATURE LATER TONIGHT WITH PERHAPS PERIODS OF THICKER MID/HIGH CANOPY BY MORNING OVER THE NORTH AND WEST MAKING FOR CLEAR TO BECOMING PARTLY/MOSTLY CLOUDY LATE. THIS ALSO PLAYS INTO JUST HOW COLD TO GO WITH LOWS OVERNIGHT GIVEN LOW DEWPOINTS AND SURFACE HIGH PRESSURE SETTLING OVER AND TO THE SOUTH OF THE AREA BY EARLY SATURDAY. EXPECT MORE CLOUDS TO START SATURDAY BUT AGAIN MOSTLY OF THE MID/HIGH VARIETY WITH MOISTURE POSSIBLY DECREASING DURING THE AFTERNOON AS ENERGY STARTS TO TRANSLATE TOWARD THE SE COAST. OTRW DRY AND A BIT WARMER UNDER AN ELONGATED AXIS OF SURFACE HIGH PRESSURE BENEATH THE PASSING MID/HIGH DECK. THINK WITH GRADUAL WARMING ALOFT WILL SEE HIGHS GET BACK INTO THE 40S...ALTHOUGH GIVEN LIGHT MIXING UNDER SOME CLOUDS MAY SEE SOME SPOTS ALONG/WEST OF THE BLUE RIDGE GET STUCK IN THE 30S UNTIL LATER IN THE DAY. THUS OPTED TO STAY SLIGHTLY BELOW MOS THERE IN CASE THE CANOPY PERSISTS LONGER OR IS THICKER. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... AS OF 250 PM EST FRIDAY... SATURDAY NIGHT A CLOSED UPPER LOW CROSSES THE SOUTHEAST UNITED STATES. ANOTHER UPPER LOW CLOSED OFF OVER THE UPPER MISSISSIPPI VALLEY ON SUNDAY MORNING WHICH BOOTS THE SOUTHER STREAM SYSTEM EAST AS IT DIGS INTO THE OHIO VALLEY MONDAY. AT THE SURFACE LOW PRESSURE MOVES THROUGH THE GREAT LAKES ON OHIO VALLEY ON MONDAY WITH A SECONDARY LOW DEVELOPING OVER THE MID ATLANTIC REGION...WHICH THEN DEEPENS OFF THE COAST ON TUESDAY. ONCE THE COASTAL LOW MOVES FAR ENOUGH NORTH AND EAST...THE SURFACE AND LOW LEVEL WINDS WILL BACK TO THE SOUTH AND SOUTHEAST...BUT THIS MAY TAKE UNTIL MONDAY AFTERNOON AND EVENING. MODELS ALSO SHOWING A REGION OF GOOD UPPER DIFFLUENCE CROSSING THE MID ATLANTIC REGION ON MONDAY. CLOUD COVER AROUND THE COASTAL LOW WILL ADVANCE INTO THE FORECAST AREA SUNDAY MORNING...WITH A MAJORITY OF THE MORE WIDESPREAD CLOUD COVER IN THE EAST. THIS MAY KEEP THE MAXIMUM TEMPERATURES A COUPLE OF DEGREES LOWER THAN FORECAST SUNDAY. MORE CLOUDS WILL ARRIVE FROM THE WEST AHEAD OF THE NORTHERN STREAM SYSTEM SUNDAY NIGHT. GFS IS SLIGHTLY FASTER WITH BRINGING THE DEEPER MOISTURE IN THE WEST ON MONDAY COMPARED TO THE NAM...BUT NOT ENOUGH TO NEED A CHANGE IN THE PROBABILITY OF PRECIPITATION FOR MONDAY. NAM...GFS AND GEFS ALL TRENDING TOWARD 0.10 TO 0.50 INCHES LIQUID EQUIVALENT FOR MONDAY AND MONDAY NIGHT...WITH THE HIGHER AMOUNTS ACROSS THE FAR NORTHERN COUNTY WARNING AREA. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 250 PM EST FRIDAY... SIGNIFICANT LOWERING OF HEIGHTS AND TEMPERATURES BY TUESDAY...WITH EASTERN 500 MB LONG WAVE TROF BEING RE-ENFORCED BY ANOTHER SHORT WAVE ON WEDNESDAY. THE TROF AXIS MOVES EAST...HEIGHTS RISE...AND TEMPERATURES MODERATE WEDNESDAY NIGHT AND THURSDAY. EXPECTING LONG FETCH OF NORTHWEST FLOW...THAT MAY EVEN TAP MOISTURE FROM THE ONLY PARTIALLY FROZEN GREAT LAKES TUESDAY NIGHT AND WEDNESDAY. QUESTIONABLE IF THE WESTERN UPSLOPE WILL CONTINUE PAST WEDNESDAY NIGHT SINCE SURFACE TO 850 MB WINDS BECOME MORE WEST BY THAT TIME. COLD 850 MB AIR WITH THE EASTERN TROF REACHES THE FORECAST AREA ON TUESDAY NIGHT AND WEDNESDAY...POTENTIALLY BOTTOMING OUT AROUND -18 BY WEDNESDAY NIGHT. WILL HIGHLIGHT POTENTIAL LOW WIND CHILL VALUES AT HIGHER ELEVATIONS IN THE FAR WESTERN COUNTY WARNING AREA IN THE HAZARDOUS WEATHER OUTLOOK. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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AS OF 1150 PM EST FRIDAY... VFR CONDITIONS EXPECTED THROUGH THE TAF VALID PERIOD WITH A VERY DRY AIR MASS AND WEAK HIGH PRESSURE ACROSS THE REGION THROUGH THE TAF VALID PERIOD. AN UPPER LOW TRACKING THROUGH THE SOUTHERN STATES WILL SPREAD INCREASING CIRRUS THROUGH THE REGION FROM THE WEST AND SOUTHWEST THROUGH THE PERIOD. CIGS WILL REMAIN AT OR ABOVE 150 THROUGH THE TAF VALID PERIOD. NO RESTRICTIONS TO VISIBILITY ARE EXPECTED. WINDS WILL BE CHAOTIC AND LIGHT...TRENDING TOWARD MOSTLY CALM AT NIGHT AND VARIABLE 3-6KTS DURING THE DAYLIGHT HOURS. IF ANY TENDENCY IN THE DIRECTION CAN BE ASCERTAINED...IT WOULD BE TOWARD THE SW-WSW. HIGH CONFIDENCE IN VFR CIGS AND VSBYS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN WIND DIRECTION THROUGH THE TAF VALID PERIOD. HIGH CONFIDENCE IN WIND SPEED THROUGH THE TAF VALID PERIOD. EXTENDED DISCUSSION... VFR CONDITIONS WILL CONTINUE INTO SUNDAY AS AN UPPER LOW REMAINS WELL SOUTHEAST OF THE REGION. AS WE MOVE INTO NEXT WEEK...A STRONG UPPER AREA OF LOW PRESSURE WILL SINK SOUTHWARD FROM THE GREAT LAKES BY MONDAY LEADING TO OVERALL MVFR CONDITIONS ACROSS MOST TAF SITES. AN ASSOCIATED COLD FRONT PASSES THROUGH MONDAY NIGHT FOLLOWED BY A SECONDARY ARCTIC BOUNDARY TUESDAY EVENING. THESE SHOULD COMBINE TO KEEP SUB-VFR OVER THE MOUNTAINS WITH LOWER CEILINGS CONTINUING WITH THE PRESENCE OF SNOW SHOWERS MONDAY NIGHT...CONTINUING THROUGH WEDNESDAY AS A STRONG UPSLOPE FLOW PATTERN KICKS IN. A MIX OF MVFR/VFR EXPECTED AT TIMES IN THE EAST WITH DOWNSLOPE LIMITING CLOUD COVER FOR TUESDAY INTO WEDNESDAY. SOME ALBERTA CLIPPERS WILL BE TRACKING THROUGH THE BASE OF THE UPPER TROUGH...WHICH COULD BRING SNOW SHOWERS AND LIGHT SNOW TO AREAS FURTHER EAST OF THE ALLEGHANYS AT TIMES.
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&& .HYDROLOGY... AS OF 240 PM EST FRIDAY... MINOR FLOODING CONTINUES AT SOUTH BOSTON ON THE DAN RIVER. THE RIVER HAS CRESTED AND WILL BE DROPPING BELOW FLOOD STAGE EARLY SATURDAY. SEE THE LATEST WBCFLSRNK PRODUCT FOR ADDED DETAILS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH NEAR TERM...JH/MBS SHORT TERM...AMS LONG TERM...AMS AVIATION...JH/JM/RAB HYDROLOGY...JH

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