000 FXUS61 KRNK 251503 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1003 AM EST MON FEB 25 2008 .SYNOPSIS... AFTER MORNING LOW CLOUDS AND FOG...WEAK HIGH PRESSURE TODAY WILL BRING DRIER AND WARMER WEATHER. A STRONG COLD FRONT WILL MOVE THROUGH THE REGION TUESDAY. BEHIND THE FRONT TUESDAY NIGHT LOOK FOR STRONG WEST WINDS AND MUCH COLDER AIR...ALONG WITH SNOW SHOWERS IN THE MOUNTAINS. THE MUCH COLDER AIR REMAINS IN THE AREA WEDNESDAY AND THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOW LEVEL FOG AT LYH/DAN HAS LIFTED. LINGERING LOW LEVEL MOISTURE ACROSS THE WEST WILL VERY SLOWLY MIX OUT AS THE FLOW BACKS TO THE SW THIS AFTERNOON AND A SHORT WAVE RIDGE BUILDS OVER THE AREA. ADJUSTED TEMPS DOWN JUST A BIT IN THE WEST DUE TO LONG-LINGERING STRATO-CU DECK. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... SOUTHWEST FLOW AND WARM ADVECTION STRENGTHENS IN ADVANCE OF THE APPROACHING STRONG COLD FRONT TONIGHT. THIS SHOULD KEEP TEMPS QUITE MILD...ESPECIALLY ON THE RIDGES. LOOKS LIKE PRE-FRONTAL SHOWERS WILL MAKE IT TO THE FAR WESTERN CWA TOWARD MORNING...SO I RAISED POPS TO CATEGORICAL IN THE FAR WEST AFTER 09Z. THE STRONGER DYNAMICS AND DEEPENING SFC LOW PRESSURE MOVES THRU THE OHIO VALLEY TUE MORNING...WHILE THE BETTER INSTABILITY REMAINS SOUTH OF THE FORECAST AREA. LOOKS LIKE MUCH OF THE FORECAST AREA WILL BE IN THE LIGHTER PRECIPITATION IN THE MIDDLE. I DID INCLUDE A SLIGHT CHC OF THUNDER IN THE NW PIEDMONT OF NC AND SOUTHSIDE VA IN THE 12 TO 18Z PERIOD. THE SFC FNT MOVES THRU MUCH OF THE MTNS BY 18Z...AND THEN EAST OF THE PIEDMONT PORTION OF THE CWA BY 00Z. I HAVE THE 12 TO 18Z PERIOD WITH CATEGORICAL POPS...AND THEN DROP THEM OFF QUICKLY IN THE AFTERNOON TUE AS A STRONG JET AND ASSOCIATED DRY SLOT MOVES ACROSS THE CWA FROM 18 TO 00Z. MODELS HAVE GOTTEN STRONGER WITH THE PRESSURE RISES TUE EVENING...AND THE LOW LEVEL JET IS STRONG ENOUGH THAT WE MAY NEED A HIGH WIND WARNING FOR ELEVATIONS ABOVE 3000 FEET AND WIND ADVISORIES FOR MOUNTAIN VALLEYS OF SW VA/NW NC TUE NIGHT INTO WEDNESDAY. THIS IS A GOOD PATTERN FOR THE AREA TO GET STRONG WINDS...WITH DEEPENING SFC LOW PRESSURE MOVING JUST NORTH OF THE CWA. WITH THE STRONG COLD ADVECTION BEHIND THE FRONT...I HAD TO HAND EDIT THE HOURLY TEMPS TUE TO HAVE THEM FALLING IN THE MID TO LATE AFTERNOON IN THE MTNS. FINALLY...WITH THE STRONG COLD ADVECTION INTO THE MTNS TUE NIGHT AND FAIRLY DEEP LOW LEVEL MOISTURE...IT LOOKS LIKE THERE WILL BE SNOW SHOWERS ON WESTERN SLOPES...ESPECIALLY AFTER 06Z AS THE LOW LEVEL FLOW BEGINS TO GET BETTER TRAJECTORY OFF LAKE MICHIGAN. I HAVE LIKELY TO CATEGORICAL POPS ON WESTERN SLOPES AREAS OVERNIGHT...WITH ACCUMULATING SNOW. I ALSO LOWERED THE MIN TEMPS INTO THE TEENS IN HIGHER ELEVATIONS AND WESTERN SLOPES WITH MINUS 14 TO 18C AT 850 MB PROGGED BY 12Z WED. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... NORTHWEST WINDS AND STRONG COLD ADVECTION WITH TRAJECTORY OFF LAKE MICHIGAN CONTINUES WED...ALONG WITH UPSLOPE SNOW SHOWERS. WILL LIKELY SEE SEVERAL INCHES OF SNOW THROUGH WED NIGHT BEFORE ANTICYCLONIC FLOW SWINGS DRIER AIR IN. ON THURSDAY...SNOW SHOWERS SHOULD HAVE COME TO AN END WITH HIGH PRESSURE SLIDING THROUGH THE REGION. ON FRIDAY...A WARM FRONT WILL SLIP THROUGH THE REGION WITH TEMPERATURES RETURNING TO NORMAL. THE NEXT CHANCE FOR PRECIPITATION TO MOVE THROUGH THE AREA WILL BE FRIDAY AFTERNOON INTO SATURDAY AS A COLD FRONT CROSSES THE AREA. HIGH PRESSURE ARRIVES SUNDAY WITH DRY WEATHER. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... SHALLOW MOISTURE IN LIGHT NORTHWEST FLOW ACROSS THE AREA HAS RESULTED IN LOW CIGS AND FOG AT BLF AND LWB...AND SHALLOW FOG DEVELOPMENT AT LYH AND DAN. THE FOG SHOULD NOT LAST MUCH PAST 12Z AT LYH AND DAN...BUT THEY MAY SEE A FEW PERIODS OF LIFR THRU ABOUT 13Z. BLF AND LWB WILL STAY MVFR TO IFR INTO MID TO LATE MORNING... UNTIL THE NORTHWEST FLOW BACKS MORE TO THE WEST AND THEN SOUTHWEST. I EXPECT BLF AND LWB TO BE VFR BY 16Z. AFTER THEN...ALL SITES SHOULD HAVE VFR CONDITIONS...WHICH WILL LAST THROUGH MUCH OF THE NIGHT. PREFRONTAL- SHOWERS AHEAD OF A STRONG COLD FRONT WILL LIKELY MOVE INTO THE BLF AND LWB AREAS BEFORE 12Z TUE. THIS WILL LOWER THEIR CONDITIONS TO MVFR. THERE IS A CHANCE THAT ROA...LYH AND DAN MAY SEE MVFR CEILINGS DEVELOP IN A LIGHT SOUTHEAST FLOW TOWARD TUE MORNING. FOR NOW...I HAVE JUST ADDED SCT LOW CLOUDS. I EXPECT CEILINGS AND VISIBILITIES TO LOWER TO AT LEAST MVFR AND OCCASIONALLY IFR TUESDAY...AS A STRONG COLD FRONT MOVES THROUGH THE REGION WITH PERIODS OF RAIN. TUESDAY NIGHT THRU WED NIGHT WILL SEE STRONG GUSTY WINDS ACROSS THE HIGHER ELEVATIONS (BLF AND ROA THE HIGHEST...BUT STRONG WINDS AT THE OTHER SITES AS WELL. THERE WILL ALSO BE NUMEROUS SNOW SHOWERS ON WESTERN SLOPES WITH ACCUMULATING SNOW LIKELY (KBLF/KLWB). HIGH PRESSURE RETURNS FRIDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/JJ NEAR TERM...JJ/JS SHORT TERM...JJ/WP LONG TERM...WP AVIATION...JJ/RCS