692 FXUS65 KTFX 180437 AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 937 PM MST TUE JAN 17 2012 .UPDATE... WEATHER DISTURBANCE ALOFT FROM SOUTHEAST B.C. INTO EASTERN WASHINGTON WILL MOVE SOUTHEAST THROUGH THE FORECAST AREA LATER TONIGHT. BANDS OF SNOW AHEAD OF THIS FEATURE OVER THE NORTHWEST ZONES WILL ALSO SPREAD SOUTHEAST. HAVE INCREASED POPS IN THE AREA OF RADAR ECHOES FOR THE REST OF THIS EVENING AND OVER MOST OF THE PLAINS AND ADJOINING MOUNTAINS AFTER MIDNIGHT. ALSO INCREASED POPS IN THE MOUNTAINS OF SOUTHWEST MONTANA LATER TONIGHT. COLD FRONT SOUTH OF A LINE FROM GREAT FALLS TO LEWISTOWN AT MID-EVENING WILL SPREAD SOUTH REACHING TO NEAR A BOZEMAN TO WHITEHALL LINE BY EARLY MORNING. HAVE ADJUSTED WIND FORECASTS TO REFLECT THIS AND ALSO HAVE LOWERED LOWS FOR TONIGHT NORTH OF THE FRONT ESPECIALLY OVER CENTRAL MONTANA AND THE NORTHERN PORTIONS OF SOUTHWEST MONTANA. NORRIS HILL IS STAYING BELOW HIGH WIND CRITERIA AS OF MID-EVENING BUT WITH UPPER FRONT EXPECTED TO MOVE THROUGH THE AREA LATER TONIGHT THINK THERE IS AN OUTSIDE CHANCE OF REACHING HIGH WIND CRITERIA SO HAVE DECIDED NOT TO CANCEL THE HIGH WIND WARNING. BLANK && .AVIATION... UPDATED 0000Z. A QUASI-STATIONARY FRONT WILL REMAIN OVER CENTRAL MONTANA BUT SHOULD STAY SOUTH OF KGTF THROUGH TONIGHT. THE FRONT IS BETWEEN KGTF AND KLWT AS OF 00Z WEDNESDAY. MOIST FLOW ALOFT WILL BRING SNOW TO THE AREA WITH WIDESPREAD MVFR/IFR CONDITIONS AFTER 06Z WEDNESDAY. SNOW DEVELOPED ALONG THE ROCKY MOUNTAIN FRONT AND ALONG THE HI-LINE LAST NIGHT AND SNOW WILL CONTINUE FOR THESE AREAS THROUGH THE PERIOD. WIDESPREAD MOUNTAIN OBSCURATION WILL CONTINUE. MLV && .PREV DISCUSSION... /ISSUED 703 PM MST TUE JAN 17 2012/ FXUS65 KTFX 180203 AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 703 PM MST TUE JAN 17 2012 UPDATE... CUT BANK IS MEETING WIND CHILL WARNING CRITERIA SO WILL UPGRADE THE ADVISORY TO A WARNING FOR GLACIER AND TOOLE COUNTIES FOR TONIGHT. ALSO WILL CHANGE ELEVATIONS ABOVE 7000 FEET FOR GALLATIN AND MADISON AND BEAVERHEAD COUNTIES FROM A WINTER WEATHER ADVISORY TO A WINTER STORM WARNING BASED ON SNOWFALL TOTALS. FINALLY ON THURSDAY AFTER HAVING LOOKED AT FORECAST SOUNDINGS WILL TONE DOWN THE MENTION OF FREEZING RAIN OVER SOUTHWEST MONTANA. BLANK && .PREV DISCUSSION... /ISSUED 500 PM MST TUE JAN 17 2012/ TONIGHT THROUGH THURSDAY...NUMEROUS WINTER WEATHER HIGHLIGHTS HAVE BEEN ISSUED TODAY. THE WINTER STORM WARNING OVER THE ROCKY MOUNTAIN FRONT AND THE WIND CHILL ADVISORY OVER THE NORTHERN TIER OF THE REGION WILL CONTINUE. A WINTER STORM WARNING HAS BEEN ISSUED FOR CENTRAL MONTANA ABOVE 5000 FEET...WITH AN ADVISORY BELOW 5000 FEET. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR PORTIONS OF SOUTHWEST AND NORTH CENTRAL MONTANA...BASICALLY THE REMAINING AREAS EXPECT HILL AND BLAINE COUNTIES. THE BULK OF THE SNOW WILL BEGIN VERY LIGHTLY TONIGHT OVER NORTH CENTRAL MONTANA...THEN SPREAD SLOWLY SOUTHWARD TOWARDS CENTRAL MONTANA BY MORNING. LIGHT SNOW SNOW WILL BE POSSIBLE OVER MUCH OF THE REGION ON WEDNESDAY...WITH A BIT HEAVIER SNOWFALL IN THE MOUNTAINS. AGAIN...THIS WILL BE A PRO-LONGED SNOW EVENT...WITH GRADUAL ACCUMULATIONS FOR MOST AREAS. THERE WILL BE SOME SHORT PERIODS OF MODERATE/HEAVY SNOW...FOLLOWED BY PERIODS OF LIGHT SNOW OR FLURRIES. TEMPERATURES WILL REMAIN COLD THROUGH THURSDAY MORNING...THEN WARMER AIR WILL START TO PUSH NORTHWARD INTO SOUTHWEST MONTANA. ENOUGH WARM AIR COULD PUSH IN ALOFT...THAT SOME FREEZING RAIN WILL BE POSSIBLE IN THE VALLEYS OF SOUTHWEST MONTANA ON THURSDAY. BRUSDA THURSDAY NIGHT THROUGH TUESDAY NIGHT...MEDIUM RANGE MODELS CONTINUE TO INDICATE THAT THE FLOW ALOFT WILL BECOME A MORE PROGRESSIVE WESTERLY ONE DURING THIS PERIOD. HOWEVER...THERE ARE SIGNIFICANT DIFFERENCES IN MOVING THE MODERATELY COOL AIRMASS AROUND NORTH CENTRAL MONTANA. THEREFORE...RATHER THAN TRYING TO TIME THE FLUCTUATIONS IN TEMPERATURES...HAVE DECIDED TO GO WITH A MORE BROAD-BRUSHED OVERALL TREND FORECAST. MODELS SOMEWHAT AGREE IN BRINGING THE WARMER (NEAR NORMAL) TEMPERATURES NORTHEAST INTO NORTH CENTRAL MONTANA BY SATURDAY...AND TEMPERATURES GENERALLY REMAIN CLOSE TO THESE LEVELS THROUGHOUT THE PERIOD. HOWEVER...THE AREA OF THE CWA NEAR THE CANADIAN BORDER WILL REMAIN SLIGHTLY BELOW NORMAL. THE GREATEST CHANCE FOR PRECIPITATION FOR THE ENTIRE AREA WILL BE EARLY IN THE PERIOD (THROUGH SATURDAY)...AS MOISTURE OVERRUNS THE LINGERING COOL AIRMASS. THE WESTERLY FLOW ALOFT WILL BE QUITE STRONG DURING THIS TIME...WHICH MAY LEAD TO STRONG WINDS IN THE MOUNTAINS (CAUSING AREAS OF BLOWING SNOW) AND IN THE SOUTHWEST MONTANA VALLEYS (ON THE WARM SIDE OF THE SURFACE BOUNDARY). AS THE COOLER AIRMASS EXITS NORTH CENTRAL MONTANA AND MORE WESTERLY DOWNSLOPE WINDS SPREAD ACROSS THAT AREA...THE CHANCE FOR SHOWERS OVER THE PLAINS AND IN THE VALLEYS WILL DECREASE THROUGH THE REMAINDER OF THE PERIOD. HOWEVER...THE CONTINUED MOIST WESTERLY FLOW ALOFT WITH ASSOCIATED WEAK DISTURBANCES WILL KEEP A GOOD CHANCE OF SNOW IN THE MOUNTAINS. COULSTON .PRELIMINARY POINT TEMPS/POPS... GTF -12 -3 -7 9 / 60 90 90 90 CTB -26 -9 -12 1 / 100 90 90 90 HLN 7 15 11 28 / 60 90 90 90 BZN 15 21 21 32 / 20 90 90 90 WEY 6 19 17 29 / 40 90 90 90 DLN 15 23 23 36 / 50 80 80 80 HVR -17 -7 -13 1 / 60 70 80 80 LWT -10 -1 -4 11 / 60 80 90 80 && .TFX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 AM WEDNESDAY TO 4 AM MST FRIDAY FOR ELEVATIONS BELOW 5000 FEET FOR CASCADE...CENTRAL AND SOUTHERN LEWIS AND CLARK...JUDITH BASIN...MEAGHER. WINTER STORM WARNING FROM 5 AM WEDNESDAY TO 4 AM MST FRIDAY FOR ELEVATIONS ABOVE 5000 FEET FOR CASCADE...CENTRAL AND SOUTHERN LEWIS AND CLARK...JUDITH BASIN...MEAGHER. WINTER WEATHER ADVISORY FROM NOON WEDNESDAY TO 4 AM MST FRIDAY CHOUTEAU...EASTERN GLACIER...EASTERN PONDERA...EASTERN TETON... FERGUS...LIBERTY...TOOLE. WIND CHILL ADVISORY UNTIL 8 AM MST WEDNESDAY BLAINE...CHOUTEAU... EASTERN PONDERA...EASTERN TETON...HILL...LIBERTY. WINTER WEATHER ADVISORY FROM 5 AM WEDNESDAY TO 4 AM MST FRIDAY BEAVERHEAD...BROADWATER...GALLATIN...JEFFERSON...MADISON. WINTER STORM WARNING FROM 5 AM WEDNESDAY TO 4 AM MST FRIDAY FOR ELEVATIONS ABOVE 7000 FEET FOR BEAVERHEAD...GALLATIN...MADISON. WIND CHILL WARNING UNTIL 8 AM MST WEDNESDAY EASTERN GLACIER... NORTHERN ROCKY MOUNTAIN FRONT...TOOLE. HIGH WIND WARNING UNTIL 5 AM MST WEDNESDAY FOR A PORTION OF MADISON COUNTY. WINTER STORM WARNING UNTIL 4 AM MST FRIDAY NORTHERN ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT. && $$ SHORT TERM...BLANK LONG TERM...MLS AVIATION...MLS WEATHER.GOV/GREATFALLS