391 FXUS61 KRLX 301629 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1129 AM EST THU DEC 30 2010 .SYNOPSIS... A MID ATLANTIC HIGH PRESSURE BUILDS WEST TONIGHT. WARM ADVECTION CONTINUES THROUGH FRIDAY. STRONG PACIFIC COLD FRONT CROSSES SATURDAY. HIGH PRESSURE OF PACIFIC ORIGIN FOLLOWS EARLY NEXT WEEK. && .NEAR TERM /THROUGH FRIDAY/... UPDATED FORECASTS TO CANCELLED FREEZING RAIN ADVISORY AS RAIN MOVED NORTH OF THE AREA BY 11 AM. ADJUSTED TEMPERATURES AND SKY GRIDS AS CLEARING SKIES DEVELOPED ACROSS THE SOUTHERN SECTIONS...SPREADING NORTH THROUGH THIS AFTERNOON. ALSO CUT POPS CONSIDERABLY FOR DRY CONDITIONS THROUGH THE REST OF THE PERIOD. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... SFC HIGH PRESSURE SHIFTS EASTWARD FRIDAY AS COLD FRONT APPROACHES FROM THE WEST. SOUTHWEST FLOW BRINGS CONSIDERABLE WARM AIR ADVECTION INTO FRIDAY NIGHT. COLD FRONT PROGGED TO MOVE THROUGH DURING THE DAY ON SATURDAY. EURO AND GFS MODELS IN PRETTY CLOSE AGREEMENT HANDLING THE PASSAGE OF FRONT THROUGH THE OHIO VALLEY AND WV ON SATURDAY. ONLY DIFFERENCE IS THAT GFS IS SLIGHTLY FASTER WITH WEST TO EAST MOISTURE TRANSITION. LATEST GFS SLOWING PROGRESS DOWN A BIT...COMING IN LINE WITH PREVIOUS RUNS OF THE EURO. FOLLOWING FROPA...CAA SETS UP FOR SUNDAY. ATMOSPHERIC COLUMN DRIES QUICKLY...HOWEVER THERE MAY BE A SHORT PERIOD SATURDAY NIGHT AND SUNDAY THAT SEES LIQUID PRECIP TRANSITIONING TO THE FROZEN VARIETY...MAINLY AS A RAIN...SNOW MIX...OR ALL SNOW TRANSITION FOR THE EASTERN MOUNTAINS EARLY SUNDAY MORNING. FOR TEMPS...USED BC MOS FIELDS WITH SLIGHT MANUAL ADJUSTMENT UPWARDS FOR THROUGH SATURDAY. THE END RESULT SHOWED LITTLE MODIFICATION TO VALUES PRESENTED IN PREVIOUS FORECAST PACKAGE. LEFT PREVIOUS TEMP FORECAST FOR SUNDAY IN PLACE. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... SFC WAVE WILL EXIT TO NE SUNDAY MORNING...ALLOWING BAROCLINIC ZONE TO RESUME THE MARCH TO THE COAST. STILL LOOKS LIKE THE PCPN COULD END AS SOME -SN OR FLURRIES BUT NOT EXPECTING MUCH IF ANY ACCUMULATION. SFC HIGH QUICKLY BUILDS IN FOR SUNDAY AFTN INTO EARLY NEXT WEEK. NOT LOOKING FOR MUCH UPSLOPE GIVEN WESTERLY COMPONENT IN THE FLOW. AS A RESULT SHOULD SEE MORE IN THE WAY OF SUN AND A BETTER DIURNAL RANGE THAN WHAT HAS BEEN OBSERVED OVER THE PAST SEVERAL WEEKS. CONTINUED TO GO BELOW GUIDANCE FOR HIGHS GIVEN LOW LEVEL TEMPS OFF THE MODELS. && .AVIATION /12Z THURSDAY THROUGH TUESDAY/... RAIN OVERSPREADING THE AREA EARLY THIS MORNING HAD BECOME RATHER WIDESPREAD UPSTREAM OVERNIGHT. THE RAIN WILL OVERSPREAD THE AREA BY MID TO LATE MORNING...AND THEN DISSIPATE DURING MIDDAY AND EARLY AFTERNOON. WITH TEMPERATURES CLOSE TO FREEZING THE PRECIPITATION CAN FREEZE ON SOME SURFACES ANYWHERE FROM A 3I2-CRW /POINT PLEASANT TO CHARLESTON/ LINE NE. THE FREEZING RAIN THREAT WILL END NEAR 14Z ALONG THE 3I2-CRW LINE...BUT AS LATE AS 17Z AT EKN...WHERE IT WON/T START TIL 14-15Z. OTHERWISE THE PRECIPITATION SHOULD BRING NO WORSE THAN MVFR CONDITIONS TO THE AREA. CONDITIONS SHOULD BE VFR THIS AFTERNOON INTO THIS EVENING...BUT AREAS OF DENSE FOG MAY FORM LATE TONIGHT CENTRAL AND NORTHERN PORTIONS OF WV...ESPECIALLY IN THE MOUNTAINS...GIVEN DEW POINTS AND TEMPERATURES ABOVE FREEZING AND NEARLY EQUAL...COMBINED WITH THE MELTING SNOW AND COLD DAMP GROUND. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: MODERATE. ALTERNATE SCENARIOS: TIMING OF PRECIPITATION...MORE FREEZING RAIN THAN EXPECTED...AND POSSIBLE IFR CONDITIONS. ALSO...TIMING AND EXTENT OF IFR DENSE FOG TONIGHT. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 CRW CONSISTENCY M M M M M M H M H H H H HTS CONSISTENCY L L M M M M H H H H H H BKW CONSISTENCY M M H H H H H H H H H H EKN CONSISTENCY H M H H H M L L H H M M PKB CONSISTENCY L L L L L L L L M M H H CKB CONSISTENCY H M M M L L L L M M M M AFTER 18Z FRIDAY... IFR POSSIBLE WITH DENSE FOG FIRST THING FRI MORNING AND IN RAIN SAT AFTERNOON WITH THE ARRIVAL OF A COLD FRONT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR WVZ031-032. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KMC/TRM NEAR TERM...ARJ SHORT TERM...KMC LONG TERM...30 AVIATION...TRM