037 FXUS65 KTFX 252209 AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 309 PM MST SUN NOV 25 2012 .DISCUSSION... TONIGHT THROUGH TUESDAY...AN UPPER TROUGH WILL BE MOVING OUT OF CENTRAL MONTANA THIS EVENING BUT STILL EXPECT LINGERING SNOW SHOWERS INTO THE EARLY EVENING FOR CENTRAL MONTANA. OTHERWISE A NORTHWEST FLOW ALOFT WILL DOMINATE AS AN UPPER RIDGE MOVES SLOWLY NORTHEAST THROUGH THE PACIFIC NORTHWEST. EXPECT HIGH LEVEL MOISTURE TO BE EMBEDDED IN THE NORTHWEST FLOW BUT LOW LEVELS WILL REMAIN DRY AND DO NOT EXPECT ANY PRECIPITATION AFTER THIS EVENING. A RELATIVELY COLDER AIRMASS WILL CONTINUE OVER NORTH CENTRAL MONTANA THROUGH TUESDAY. WILL CONTINUE WITH THE WINTER WEATHER ADVISORY TO 8 PM FOR PORTIONS OF THE AREA. SNOW SHOWERS CONTINUE OVER MOST OF THE ADVISORY AREA AS OF MID-AFTERNOON BUT EXPECT THEM TO DIMINISH FROM THE NORTHWEST LATER THIS AFTERNOON AND EARLY EVENING AND IT IS POSSIBLE THAT PORTIONS OF THE WINTER WEATHER ADVISORY COULD BE CANCELLED BEFORE 8 PM. BLANK TUESDAY NIGHT THROUGH FRIDAY...A QUIET WEATHER PATTERN CAN BE EXPECTED OVER THE REGION FOR TUESDAY AND WEDNESDAY...AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE RESIDES OVER THE REGION. NO PRECIPITATION IS EXPECTED...BUT A SLOW WARMING TREND IS ANTICIPATED. FOR THURSDAY AND INTO FRIDAY...THE FLOW ALOFT BECOMES A BIT MORE SOUTHWESTERLY...RESULTING IN A FEW UPPER LEVEL DISTURBANCES MOVING THROUGH THE REGION. THUS THE CHANCES FOR PRECIPITATION HAVE BEEN INCREASED A BIT...ESPECIALLY OVER THE WESTERN MOUNTAINS. PRECIPITATION AMOUNTS DO NOT LOOK TO BE EXCESSIVE AT THIS TIME...AND WITH LOWER ELEVATION TEMPERATURES IN THE 40S/50S...MOST OF THE PRECIPITATION AT LOWER LEVELS WILL BE RAIN...POSSIBLY MIXED WITH SNOW AT TIMES DURING THE OVERNIGHT OR EARLY MORNING HOURS...BUT ANY SIGNIFICANT SNOWFALL ACCUMULATIONS WILL BE CONFINED MAINLY TO RIDGE TOPS. FOR NEXT SATURDAY AND SUNDAY...BOTH THE GFS AND ECMWF DIFFER QUITE A BIT. BOTH MODELS HAVE A STORM SYSTEM MOVING THROUGH THE AREA...BUT THE EC HAS THE STORM MOVING THROUGH LATE FRIDAY AND SATURDAY MORNING...WHILE THE GFS HAS THE STORM MOVING THROUGH SUNDAY. THUS TEMPERATURES AND POPS ARE QUITE A BIT DIFFERENT ON BOTH MODELS...SO WITH THE OVERALL FORECAST...I WENT WITH A COMPROMISE AT THIS TIME...UNTIL BETTER AGREEMENT ON TIMING AND LOCATION OF PRECIPITATION CAN BE DETERMINED FOR NEXT WEEKEND. OVERALL...CONFIDENCE IN THE FORECAST FOR NEXT WEEKEND AT THIS TIME IS VERY LOW. BRUSDA && .AVIATION... UPDATED 1810Z. CONDITIONS WILL BE MAINLY VFR WITH OCCASIONAL IFR AFFECTING KHVR AND KLWT IN SNOW SHOWERS. THERE COULD BE BRIEF LIFR CONDITIONS AFFECTING KHVR AND KLWT. AM CONFIDENT THAT KCTB WILL BE VFR BY EARLY EVENING BUT HAVE LOW CONFIDENCE IN THE TIMING OF WHEN CONDITIONS THERE WILL GO VFR. HAVE KEPT KGTF VFR BUT WOULD NOT BE SURPRISED IF THEY GO BRIEFLY MVFR IN SNOW SHOWERS THIS AFTERNOON. CLOUDS WILL DIMINISH OVERNIGHT. && .PRELIMINARY POINT TEMPS/POPS... GTF 21 38 25 43 / 20 0 0 0 CTB 11 33 16 38 / 10 0 0 0 HLN 13 35 21 42 / 10 0 0 0 BZN 9 28 14 42 / 10 0 0 0 WEY -6 25 8 34 / 30 0 0 0 DLN 13 34 18 41 / 10 0 0 0 HVR 10 28 8 27 / 30 0 0 0 LWT 14 36 16 39 / 60 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING NORTHERN ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT. WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING BLAINE... CASCADE...CHOUTEAU...FERGUS...HILL...JUDITH BASIN...LIBERTY... MEAGHER...TOOLE. WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING GALLATIN... MADISON. && $$ WEATHER.GOV/GREATFALLS