000 FXUS63 KEAX 261102 AFDEAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 502 AM CST WED DEC 26 2007 .DISCUSSION... MAIN FORECAST CONCERNS WILL BE WITH PRECIPITATION CHANCES TODAY AND AGAIN THURSDAY NIGHT INTO FRIDAY. CURRENTLY WATCHING THE PROGRESS OF LIGHT SNOW BAND STRETCHING FROM NORTHWEST IA SOUTHWARD THROUGH SOUTHEAST NE AND INTO CENTRAL KS. TIMING HAS THIS FEATURE CREEPING INTO THE NORTHWEST CORNER OF MISSOURI AROUND 12Z. CURRENTLY UNIMPRESSED WITH SNOW PRODUCTION OUT OF THIS SYSTEM WITH THE SNOW BAND AXIS COINCIDING WITH MODERATE H85-H7 FRONTOGENETICAL FORCING. HOWEVER...WITH STRONGER UPPER SUPPORT FURTHER SOUTH ACROSS THE SOUTHERN PLAINS ALONG WITH DECENT MID LEVEL DRY LAYER TO OVERCOME...SNOW PRODUCTION HAS BEEN LACKING THUS FAR. MODELS INDICATE THE SNOW BAND TO STEADILY WEAKEN THIS MORNING AS FRONTOGENETICAL FORCING SLOWLY DWINDLES. IN ADDITION...ANY PRECIP THAT DEVELOPS ACROSS THE SOUTHERN HALF OF THE CWA WILL LIKELY HAVE TO BATTLE A WARMER SFC LAYER. THEREFORE...KEPT A MENTION OF RAIN/SNOW MIX ACROSS THIS AREA THIS MORNING WITH THE CENTRAL COUNTIES LIKELY CHANGING OVER TO ALL SNOW BY THE AFTERNOON. KEPT THE SOUTHEASTERN COUNTIES IN A LONGER DURATION OF THE RAIN/SNOW MIX AS THIS AREA LOOKS TO BE SLOWER TO COOL THE LOW LEVELS. EXPECTING THE BAND TO EXPAND SOMEWHAT AGAIN BY THE AFTERNOON HOURS AS BETTER EPV SPREADS EASTWARD AHEAD OF MEAN TROUGH AXIS. OVERALL...WITH THE RECENT HISTORY OF THIS SYSTEM AND ONLY MODEST DYNAMICS EXPECTED...TONED DOWN SNOW ACCUMULATIONS A BIT AND THINK MOST AREAS WILL REMAIN UNDER AN INCH. SNOW SHOULD GRADUALLY SHIFT EAST TONIGHT BEFORE EXITING BY TOMORROW MORNING. SOME CONCERN WITH LINGERING STRATUS OVERNIGHT AS MODELS INDICATING LOW LEVELS REMAINING FAIRLY SATURATED. NOT COMPLETELY SOLD ON THE IDEA AS SOME CONCERN THE DRIER AIR CURRENTLY ACROSS NEBRASKA WILL FILTER SOUTHWARD. THEREFORE...THINKING THE EASTERN COUNTIES WILL HAVE THE BEST SHOT AND KEPT HIGHER CLOUD COVER AND MENTION OF DRIZZLE OR FREEZING DRIZZLE FOR THESE AREAS. ATTENTION THEN TURNS TO THE NEXT SHORT WAVE TROUGH TO AFFECT THE AREA WITHIN THE PROGRESSIVE PATTERN. VERY COLD SYSTEM ALREADY EVIDENT COMING ONSHORE ACROSS THE PACIFIC NORTHWEST WITH COLD CORE CU ALREADY SHOWING UP. SYSTEM BECOMING BETTER SAMPLED TONIGHT AS IT PUSHES INTO THE RAOB NETWORK WITH 00Z QUILLAYUTE, WA SOUNDING INDICATING H5 TEMPS OF -35 DEGREES. SUBSEQUENTLY...MODELS COMING INTO BETTER AGREEMENT WITH THE TIMING AND PLACEMENT. STAYED CLOSE TO THE MORE CONSISTENT ECMWF WITH OPERATIONAL GFS AND NAM ALSO COMING IN FAIRLY SIMILAR. MEAN UPPER TROUGH AXIS SWINGS INTO THE CENTRAL PLAINS THURSDAY NIGHT AND APPROACHES OUR NECK OF THE WOODS BY FRIDAY MORNING. OVERALL...A BIT OF A SOUTHWARD TREND HAS BEEN THE RULE AND HAVE TAKEN PRECIP SWATH AND SUBSEQUENT HIGHER SNOW TOTALS SOUTH AS WELL. UPPER TROUGH AXIS PROGGED TO BECOME SOMEWHAT NEGATIVELY TILED AS IT SWINGS THROUGH THE AREA WITH 125+KT H25 JET ROUNDING ITS BASE BY FRIDAY MORNING. MAIN VORT MAX APPEARS TO PUSH INTO SOUTHEASTERN KS BY EARLY FRIDAY MORNING AND THEN LIFTS NORTHEASTWARD THROUGH FRIDAY NIGHT. THIS PLACES STRONGER FRONTOGENETICAL FORCING FOR BANDED PRECIP ACROSS CENTRAL MISSOURI...PERHAPS ENCOMPASSING THE SOUTHERN COUNTIES DURING THE EVENT. HOWEVER...WITH SUCH COLD TEMPS ALOFT STEEPENING LAPSE RATES AS THE COLD CORE CENTER APPROACHES...IN ADDITION TO FAIRLY STRONG QG FORCING...SHOULD LEND TO DECENT SNOWFALL RATES ACROSS MANY AREAS. YET...SOME LIMITING FACTORS DO COME INTO PLAY AS THE SYSTEM TRANSITIONS...MAINLY THE OVERALL SPEED AND THE CHANCE OF DRY AIR LIMITING SNOW GROWTH POTENTIAL...ALTHOUGH LESS CONCERNED WITH THE LATTER AS A MORE SOUTHERN TRACK WOULD PLACE THE DRY SLOT ACROSS SOUTHERN MISSOURI. NEVERTHELESS...A QUICK BURST OF A FEW INCHES OF SNOW WILL CERTAINLY BE POSSIBLE AND HAVE PAINTED HIGHER AMOUNTS ACROSS THE SOUTHERN 2/3RD OF THE CWA CLOSER TO THE PATH OF THE VORT MAX TRACK AND BETTER FRONTOGENETICAL FORCING. HOWEVER...EXPECTING MOST AREAS TO SEE AT LEAST SOME SNOWFALL AS COLD CORE IS EXPECTED TO SWING VERY NEAR. PRECIP SHOULD START TO WIND DOWN FROM WEST TO EAST FRIDAY AFTERNOON EXITING THE EASTERN COUNTIES BY FRIDAY NIGHT. DEROCHE && .AVIATION... LOWER CLOUD DECK INCHING ACROSS NORTHEAST KANSAS AND FAR NORTHWEST MISSOURI EARLY THIS MORNING. CURRENT TIMING BRINGS LOWER CEILINGS ACROSS THE TERMINALS BY 19-20Z WITH SNOW CHANCES INCREASING AROUND THIS TIME AS WELL. NOT EXPECTING THIS TO BE A LONG DURATION EVENT AS FAR AS PRECIP IS CONCERNED...ALTHOUGH LOW CLOUD DECK MAY LINGER INTO THE EARLY MORNING HOURS THURSDAY. DEROCHE/21 && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$