769 FXUS65 KBYZ 111643 AFDBYZ AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BILLINGS MT 943 AM MST MON FEB 11 2013 .SHORT TERM...VALID FOR TDY AND TUE... ONLY MINOR ADJUSTMENTS FOR THE MORNING UPDATE PACKAGE. MAIN FORECAST CHALLENGE TODAY IS TEMPERATURES WITH ALL THE NEWLY FALLEN SNOW...DOWNSLOPE WINDS AND DRAINAGE FLOWS. THE PRIMARY IMPACT WE ARE EXPECTING TODAY IS THE CLARKS FORK DRAINAGE SET UP KEEPING BILLINGS BELOW MODEL GUIDANCE. THIS LOOKS ON TRACK BASED ON BELOW ZERO TEMPERATURES IN THE BIG HORN BASIN AND OBSERVED LOW LEVEL WIND FIELDS INTO THE YELLOWSTONE VALLEY. MY ONLY CONCERN IS THE WIND FIELDS ARE SOMEWHAT WEAK TO THE SOUTH...BUT ANY AIR THROUGH THE VALLEY WILL NOT MODERATE MUCH DUE TO THE NEW SNOW IN CARBON COUNTY. FOR THE AFTERNOON PACKAGE I WILL BE CONCENTRATING ON WIND ISSUES IN THE WEST AND A POTENTIAL PRECIPITATION EVENT AT MID WEEK. BT .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... MODELS REMAIN IN GOOD AGREEMENT FOR WEDNESDAY THROUGH FRIDAY WITH UNSETTLED WEATHER PATTERN ACROSS THE REGION. UNSTABLE NORTHWEST FLOW WILL BE OVER THE REGION WITH SEVERAL SHORT WAVES MOVING THROUGH. GAP FLOW WINDS DEVELOPING TUESDAY NIGHT WILL CONTINUE ON WEDNESDAY BUT WILL DIMINISH BY LATE AFTERNOON AS A COLD FRONT BACK DOORS INTO THE AREA. THURSDAY WILL SEE LIGHTER WINDS BUT ANOTHER SHORT WAVE WILL DROP INTO OUR AREA AS FLOW ALOFT BECOMES NORTHERLY AND STRONG COLD AIR ADVECTION DEVELOPS. UPPER RIDGE OF HIGH PRESSURE WILL BUILD IN FRIDAY AND SATURDAY FOR DRY WEATHER. FLOW ALOFT ONCE AGAIN BECOMES PROGRESSIVE AS ANOTHER TROUGH MOVES IN FROM THE PACIFIC NORTHWEST. THERE IS SOME MODEL UNCERTAINTY ON THE STRENGTH OF THIS TROUGH. THE ECMWF MOVES A SPLITTING TROUGH ACROSS OUR AREA WHEREAS THE GFS HAS A MUCH DEEPER TROUGH MOVING IN. WILL EASE INTO THIS TIME PERIOD BY ADDING ISOLATED POPS FOR NOW AND WILL SEE HOW LATER MODEL RUNS EVOLVE THIS TROUGH. TEMPERATURES WILL BE NEAR SEASONAL WEDNESDAY BUT WILL FALL TO BELOW NORMAL VALUES THURSDAY AND FRIDAY WITH NORTHERLY FLOW ALOFT. RIDGING FRIDAY AND SATURDAY WILL BRING SEASONAL TEMPERATURES BACK TO THE REGION ONLY TO FALL AGAIN TO BELOW NORMAL SUNDAY AND MONDAY WITH UPPER TROUGH OVER THE REGION. RICHMOND && .AVIATION... DRIER AIR MOVING INTO THE REGION WILL RESULT IN VFR CONDITIONS AT ALL FLIGHT TERMINALS TODAY. MVFR/IFR CEILINGS WILL CONTINUE TO BURN OFF ACROSS FAR SOUTHEASTERN MONTANA OVER THE NEXT FEW HOURS. WEST TO SOUTHWEST WINDS GUSTS OVER 30 KTS WILL BE COMMON TODAY FROM KLVM TO BIG TIMBER. STC && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 030 022/043 030/045 024/034 018/037 026/047 026/043 0/U 00/B 14/W 32/S 21/B 10/B 02/W LVM 034 025/038 031/042 024/032 016/036 027/046 031/041 0/N 01/N 14/W 43/S 21/E 11/N 12/W HDN 034 016/040 026/044 022/035 014/036 021/047 023/043 0/U 00/B 14/W 32/S 21/B 10/B 02/W MLS 034 021/038 029/042 024/031 014/033 025/044 025/042 0/U 00/B 14/W 32/S 21/B 10/B 01/B 4BQ 029 016/037 026/042 022/031 011/032 021/042 021/040 0/U 00/B 14/W 33/S 21/B 10/B 01/B BHK 029 019/037 026/038 021/027 009/028 019/037 020/038 0/U 00/B 03/J 33/S 21/B 10/B 01/B SHR 030 012/038 022/041 018/030 012/032 018/043 019/040 0/U 00/B 14/W 33/S 22/S 10/B 02/J && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS