FXUS65 KBYZ 171517 AFDBYZ AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BILLINGS MT 917 AM MDT MON MAR 17 2014 .UPDATE... PACIFIC FRONT HAS MOVED THROUGH LIVINGSTON ON TRACK FOR A 10 AM ARRIVAL IN BILLINGS WITH POLAR FRONT HAVING PASSED GREAT FALLS. BREEZY CONDITIONS AND SHOWERY ACROSS THE WESTERN HALF OF THE AREA TODAY BEHIND THE PACIFIC FRONT BUT SNOW WILL HOLD OFF UNTIL LATER THIS AFTERNOON WHEN POLAR FRONT ARRIVES. STILL LOOKS BEST FOR SNOW TO CREATE LOCALIZED PROBLEMS WEST OF BILLINGS AND BETTER SNOWFALL EXPECTED THIS EVENING SOUTH AND EAST OF BILLINGS. NO UPDATES. BORSUM && .SHORT TERM...VALID FOR TDY AND TUE... A POTENT BUT QUICK MOVING STORM SYSTEM WILL BRING STRONG WINDS...RAIN TURNING TO SNOW...AND ISOLATED THUNDERSTORMS TO THE AREA TODAY. BY TONIGHT PRECIPITATION WILL BE ALL SNOW WITH AREAS OF BLOWING SNOW. SYSTEM EXITS THE AREA TUESDAY MORNING WITH SOME LIGHT RESIDUAL SNOW SHOWERS INTO TUESDAY NIGHT. A STRONG STORM SYSTEM IS CENTERED OVER NORTHERN WASHINGTON THIS MORNING WITH A STRONG SUBTROPICAL MOISTURE FEED OUT AHEAD OF IT SPREADING CLOUDS ACROSS THE AREA THIS MORNING. SURFACE FRONT IS TAKING SHAPE ALONG THE CONTINENTAL DIVIDE AT 4AM WITH SNOW ALREADY FALLING OVER MOUNTAINS OF WESTERN MONTANA. EXPECT THIS FRONT TO PUSH THROUGH LIVINGSTON EARLY THIS MORNING AND ARRIVE IN BILLINGS BEFORE NOON. ONCE THE FRONT GETS THROUGH BILLINGS IT WILL ACCELERATE THROUGH THE REST OF THE AREA DURING THE AFTERNOON HOURS. VERY COLD AIR IS ASSOCIATED WITH THE UPPER LEVEL CIRCULATION OF THIS STORM SYSTEM. THIS WILL LEAD TO VERY STEEP LAPSE RATES ACROSS THE AREA TODAY INTO TONIGHT. THIS INSTABILITY WILL ALLOW STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE CREATING WIDESPREAD GUSTS OF 35 TO 45 MPH THIS AFTERNOON INTO TONIGHT. WINDS WILL START OFF WESTERLY THIS MORNING WHICH HAS DRIED OUT THE LOWER ATMOSPHERE SO IT WILL TAKE A WHILE FOR PRECIPITATION TO GET GOING TODAY. AS WINDS TURN NORTHWESTERLY THIS AFTERNOON MORE LOWER ELEVATION AND FOOTHILLS AREAS WILL SEE PRECIPITATION...HOWEVER DOWNSLOPING OFF THE LITTLE BELT...SNOWY AND BULL MOUNTAINS WILL TEMPER THE PRECIPITATION FROM BILLINGS WEST TO BIG TIMBER AND HARLOWTON. THESE AREAS WILL SEE PRECIPITATION BANDS AND A PERIOD OF PRECIPITATION WITH THE FRONT BUT NOT THE MORE PERSISTENT PRECIPITATION FOUND FURTHER EAST AND INTO THE FOOTHILLS OF THE PRYOR/BIG HORN MOUNTAINS. AREAS FROM NYE TO RED LODGE DO NOT LOOK FAVORED FOR SIGNIFICANT SNOW WITH THIS EVENT...BUT IF WINDS TURN JUST A BIT MORE NORTHERLY WILL HAVE THE POTENTIAL FOR HEAVIER AMOUNTS SO WILL HAVE TO WATCH THESE AREAS CLOSELY. ISSUED A WINTER WEATHER ADVISORY FOR JUDITH GAP FOR STRONG NORTHERLY WINDS AND PERIODS OF INTENSE SNOWFALL MAKING TRAVEL DIFFICULT THERE. ALSO POSTED A WINTER WEATHER ADVISORY FOR LIVINGSTON AND THE PARADISE VALLEY WHERE STRONG INSTABILITY AND NORTH-NORTHWEST WINDS SHOULD PRODUCE SIGNIFICANT UPSLOPE SNOW ALONG WITH BLOWING SNOW IMPACTING PORTIONS OF I-90 AND HIGHWAY 89. IN ADDITION...THE STRONG INSTABILITY TODAY MAY BE ENOUGH TO GENERATE A FEW THUNDERSTORMS AS THE FRONT MOVES ACROSS THE AREA. BURST OF INTENSE RAIN/SNOW CAN BE EXPECTED WITH ANY THUNDERSTORMS THAT DO DEVELOP ALONG WITH STRONG WIND GUSTS. ONCE THE FRONT PUSHES THROUGH THE AREA THIS AFTERNOON PRECIPITATION WILL TURN FROM A MIX OF RAIN/SNOW TO ALL SNOW THIS EVENING. AREAS FROM SOUTHERN BIG HORN EAST INTO CARTER COUNTY WILL SEE THE POTENTIAL FOR THE HEAVIEST SNOW ACCUMULATIONS ALONG WITH BLOWING SNOW AND A WINTER WEATHER ADVISORY IS IN PLACE. ROADS WILL BE MAINLY WET UNTIL MID EVENING WHEN THE METRO MODEL SUGGEST ROADS WILL BECOME ICY AND SNOWPACKED IN THESE AREAS. THE BIG HORN MOUNTAINS COULD SEE 6 TO 10 INCHES OF SNOW TONIGHT. BULK OF THE STORM SYSTEM PUSHES WELL SOUTHEAST OF THE AREA BY TUESDAY MORNING BRINGING AN END TO THE SIGNIFICANT SNOW ACCUMULATIONS. BLOWING SNOW COULD REMAIN A PROBLEM INTO MID DAY OVER SOUTHERN AND SOUTHEAST COUNTIES. WRAP AROUND INSTABILITY SNOW SHOWERS WILL LIKELY CONTINUE ACROSS THE AREA INTO TUESDAY EVENING BEFORE PRECIPITATION FINALLY ENDS. WESTERLY WINDS WILL HELP PUSH TEMPERATURES INTO THE MID 30S TO MID 40S FOR TUESDAY AFTERNOON HELPING TO MELT SNOW AND IMPROVE TRAVEL CONDITIONS. CHAMBERS .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... MODELS REMAIN IN PRETTY GOOD AGREEMENT FOR THE EXTENDED PERIOD...FAVORING A A COOLER AND PROGRESSIVE PATTERN. A STRONG WEATHER SYSTEM WILL CROSS THE REGION TO END THE WORK WEEK...AND SEVERAL WEAKER WAVES ARE PROGGED THROUGH THE REMAINDER OF THE PERIOD. A SHORT PERIOD OF RIDGING IS IN CONTROL OVER THE REGION WEDNESDAY...AHEAD OF THE NEXT SYSTEM BEGINS TO IMPACT WEST MOUNTAINS WEDNESDAY NIGHT. TIMING APPEARS TO BE COMING INTO BETTER AGREEMENT...AND CURRENTLY LOOKS VERY CLOSE. ALTHOUGH DYNAMICS MAY NOT BE AS STRONG DUE TO STREAM WISE VORTICITY...SHOWER DEVELOPMENT SHOULD NOT BE A PROBLEM....WITH SNOW IN THE HIGH TERRAIN..AND A MIX ACROSS LOWER ELEVATIONS. THIS SYSTEM LOOKS LIKE IT COULD BRING A GOOD INITIAL SHOT OF HEAVY SNOW INTO COOKE CITY IN SOUTHWEST FLOW EARLY THURSDAY...BUT WILL BE SHORT LIVED AS TROF AXIS SHIFTS EAST. WINDS WILL SHIFT NORTHERLY OVERNIGHT...AND FAVOR NORTH FACING SLOPES FOR HEAVY PRECIPITATION THROUGH MUCH OF THE DAY FRIDAY. THIS NORTHERLY FLOW WILL ALSO BRING A SURGE OF COLD AIR...WILL AFFECT A SIGNIFICANT COOLING TREND INTO THE WEEKEND. RAISED POPS ACROSS MUCH OF THE REGION THROUGH THE PERIOD...BUT ESPECIALLY IN COOKE CITY LATE WEDNESDAY AND EARLY FRIDAY...AND ON NORTH FACING SLOPES THROUGH FRIDAY. ALSO CONTINUED TRENDING COOLER INTO THE WEEKEND. UNSETTLED NORTHWEST FLOW CONTINUES OVER THE REGION THROUGH SUNDAY...WITH WEEK SHORTWAVES SLIDING THROUGH THE REGION. PRECIP CHANCES WILL BE RELATIVELY SLIGHT THROUGH THE WEEKEND...WITH LIMITED MOISTURE AVAILABILITY. EXPECT A WARMING TREND THROUGH THE WEEKEND...BUT FAIRLY SLOW DUE TO PERSISTENT NORTHWEST FLOW AND CONTINUED PERIOD IC SHORTWAVE ACTIVITY. MODELS DIVERGE A BIT AT THIS POINT...WITH MORE SIGNIFICANT WAVE SLIDING THROUGH THE REGION SUNDAY NIGHT IN THE EC...WITH GFS BRINGING RIDGING BACK INTO THE REGION. KEPT SLIGHT POPS THROUGH THE LATTER PORTIONS OF THE EXTENDED AT THIS TIME...ERRING ON SIDE OF CAUTION. WILL BARE WATCHING AS GETS CLOSER IN TIME. AAG && .AVIATION... A COLD FRONT WILL MOVE THROUGH THE REGION TODAY...SWITCHING WINDS TO MORE OF A N OR NW DIRECTION. WINDS WILL BE STRONGEST FROM MID DAY TODAY THROUGH LATE THIS EVENING...WHEN GUSTS OVER 35 KTS WILL BE COMMON ACROSS THE REGION. GUSTS MAY APPROACH 45 KTS IN THE KSHR AREA BY EARLY THIS EVENING. RAIN AND SNOW SHOWERS WILL INCREASE THROUGH THE DAY...WITH A FEW THUNDERSTORMS POSSIBLE THIS AFTERNOON. PRECIP WILL GRADUALLY CHANGE TO ALL SNOW BY THIS EVENING AND CONTINUE INTO TONIGHT. MVFR/IFR CONDITIONS WILL BECOME MORE WIDESPREAD THIS AFTERNOON AND WILL CONTINUE INTO TONIGHT...WITH AREAS OF LIFR PROBABLE. EXPECT MOUNTAIN OBSCURATION THROUGH TONIGHT. STC && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 048 029/044 027/050 031/048 026/037 020/041 022/043 6/T 63/W 11/B 24/W 33/J 22/J 12/W LVM 050 023/038 024/045 027/043 020/034 014/040 018/040 +/W 93/W 11/N 34/W 33/J 21/B 22/J HDN 050 030/044 026/049 031/049 026/038 018/042 021/044 8/T 84/W 11/B 24/W 44/J 22/W 12/W MLS 050 030/044 027/050 031/050 028/037 019/041 021/043 8/T 94/W 21/B 13/W 34/J 22/J 12/W 4BQ 054 030/042 025/048 029/049 027/038 019/041 020/042 4/T +5/W 21/B 13/W 34/J 22/W 12/W BHK 052 027/039 025/046 027/048 025/034 017/037 018/039 8/T +4/W 31/B 13/W 45/J 22/J 12/J SHR 055 028/039 020/047 024/047 023/036 015/041 017/042 4/T +5/W 21/B 13/W 33/J 23/J 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO NOON MDT TUESDAY FOR ZONES 36>38-57-58. WINTER WEATHER ADVISORY IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR ZONE 63. WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MDT TUESDAY FOR ZONES 64-65. WY...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO NOON MDT TUESDAY FOR ZONE 99. WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MDT TUESDAY FOR ZONE 98. && $$ WEATHER.GOV/BILLINGS  FXUS65 KBYZ 171622 AFDBYZ AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BILLINGS MT 1022 AM MDT TUE MAR 17 2015 .UPDATE... ADJUSTED CHANCES OF PRECIPITATION BASED ON CURRENT RADAR TRENDS AND RAPID REFRESH MODEL PROJECTIONS. EXPECT ACTIVITY THIS AFTERNOON TO BE MORE SHOWERY. REGARDLESS AIRMASS IS VERY MOIST AND UPSLOPE FLOW WILL KEEP LOW CLOUDS AND HIGH HUMIDITY IN THE AREA. THIS WILL MAKE IT SEEM DAMP EVEN IF MUCH MOISTURE IS NOT FALLING FORM THE CLOUDS. LOWERED TEMPERATURES WESTERN AREAS AS THE NEXT ROUND OF LIFT BEGINS MOVING IT WILL MAINTAIN CLOUD THICKNESS AND LIMIT SOLAR INSOLATION. BORSUM && .SHORT TERM...VALID FOR TDY AND WED... A VERY MOIST AIRMASS HAS MOVED INTO THE FORECAST AREA WITH STANDARD DEVIATIONS OF 3-4 ABOVE NORMAL ON PRECIPITABLE WATER VALUES. THIS AIRMASS WILL BE SLOW TO MOVE AS IT WAS BEING REPLENISHED BY A TROPICAL FEED FROM THE BAHA. THIS WILL LEAD TO PLENTY OF MOISTURE AVAILABLE FOR PRECIPITATION THE NEXT COUPLE OF DAYS. OVERALL THOUGH...DESPITE THE DEEPLY MOIST AIRMASS...FORCING WILL BE RELATIVELY WEAK...AND THUS AM NOT EXPECTING A LARGE PRECIPITATION EVENT. SHOULD BE FAIRLY WET TODAY WITH WARM ADVECTION ALOFT CAUSING GENERALLY LIGHT PRECIPITATION MOST OF THE DAY. MODELS INDICATE THAT THE BEST SURGE OF FORCING WILL BE THIS MORNING...WITH A BIT OF A LULL THIS AFTERNOON. WILL KEEP POPS HIGH EVEN INTO THE AFTERNOON THOUGH...AS WILL NOT TAKE MUCH FORCING TO GENERATE A FEW LIGHT SHOWERS IN THIS DEEPLY MOIST AIRMASS. LOW LEVELS WILL BE ADEQUATELY COLD ENOUGH FOR SNOW THIS MORNING. A WARM GROUND SHOULD LIMIT ACCUMULATIONS THOUGH WITH WET ROADS STAYING MAINLY WET. A SECOND WAVE OF FORCING MOVES IN FROM THE WEST THIS EVENING AND MOVES ACROSS WESTERN AND CENTRAL ZONES TONIGHT AND WEDNESDAY. WILL KEEP HIGH POPS FOR THIS AS JET FORCING WILL PLAY A ROLE IN POSSIBLY MAKING THIS TIME FRAME A MORE PRODUCTIVE PRECIPITATION MAKER. LOW TO MID LEVEL TEMPERATURES WILL BE RISING THROUGH THIS PERIOD AND BELIEVE THE PRECIPITATION WILL BE MAINLY RAIN...OR A RAIN AND SNOW MIXTURE. THE MOUNTAINS AND FOOTHILLS WILL HAVE THE BEST CHANCE OF GETTING ACCUMULATIONS...BUT ACCUMULATIONS SHOULD BE ON THE LIGHT SIDE EVEN IN THESE LOCATIONS DUE TO WEST TO SOUTHWEST FLOW AT 700MB...AND THE FACT THAT AIRMASS IS NOT EXPECTED TO BE VERY COLD. THE TROUGH FORCING THE SHOWERS TONIGHT AND WEDNESDAY WILL SHIFT EAST AND PUSH THE DEEP MOISTURE OUT...REPLACING IT WITH DRYING FLOW FROM THE NORTHWEST WEDNESDAY NIGHT. THIS WILL EFFECTIVELY TAPER OFF SHOWER CHANCES. LOOKS LIKE A DAMP COUPLE OF DAYS AHEAD WITH SOME AREAS RECEIVING OVER A THIRD OF AN INCH OF PRECIPITATON. MOST PLACES WILL NOT GET THAT MUCH AND BE CLOSER TO TWO TENTHS. AFTER THE LATEST DRY SPELL THOUGH...ANY PRECIPITATION IS NEEDED. TWH .LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON... THE EXTENDED FORECAST LOOKS TO BE IN PRETTY GOOD SHAPE BUT DID MAKE A FEW ADJUSTMENTS FOR NEXT WEEKEND. HIGH PRESSURE RIDGING WILL BE OVER THE FORECAST AREA THURSDAY AND FRIDAY RESULTING IN DRY AND MILD CONDITIONS. HOWEVER...A BACK DOOR FRONT STILL LOOKS TO SLIDE INTO THE EASTERN ZONES FRIDAY AFTERNOON USHERING IN AN EASTERLY WIND AND COOL DOWN WITH TEMPERATURES COMPARED TO OUR CENTRAL AND WESTERN AREAS. SATURDAY WILL SEE AN UPPER LOW AND TROUGH MOVE OUT OF THE PACIFIC NORTHWEST INTO IDAHO AND WESTERN MONTANA SHIFTING THE RIDGE AXIS EAST. AS THIS THROUGH MOVES EAST...IT WILL BRING A PACIFIC FRONT ACROSS THE AREA INCREASING SHOWER CHANCES FROM WEST TO EAST SATURDAY AFTERNOON THROUGH SUNDAY. THE EASTERN WINDS ACROSS THE EAST MAY INHIBIT THIS SECOND FRONT FROM GETTING THROUGH THE FAR EASTERN ZONES AS MODELS KEEP COOLER AIR ACROSS THIS AREA. AS A RESULT...DID LOWER TEMPERATURES SEVERAL DEGREES SATURDAY AND SUNDAY ACROSS THE FAR EAST...ESPECIALLY ALONG THE DAKOTA BORDERS. THE SYSTEM EXITS THE AREA BY MONDAY AND TUESDAY BRINGING A RETURN TO DRY CONDITIONS ALONG WITH SLIGHTLY WARMER TEMPERATURES MONDAY AND ESPECIALLY TUESDAY. HOOLEY && .AVIATION... FAIRLY HIGH CONFIDENCE THAT AREAS OF LIFR TO VLIFR CEILINGS AND VISIBILITIES WILL AFFECT KLVM AND KBIL THIS AFTERNOON AND TONIGHT...AS AREAS OF RAIN AND SNOW MOVE THROUGH THE REGION. MVFR CONDITIONS CAN BE EXPECTED AT KMLS AND KSHR THROUGH TONIGHT. GENERALLY MVFR CONDITIONS ARE EXPECTED WED MORNING...WITH VFR AT KLVM. ARTHUR && .PRELIMINARY POINT TEMP/POPS... TDY WED THU FRI SAT SUN MON ------------------------------------------------------- BIL 041 035/053 036/060 036/066 037/063 037/054 031/056 4/W 74/W 31/U 00/B 01/B 22/W 10/B LVM 043 035/048 034/058 035/064 037/062 034/053 029/055 4/W 76/W 21/U 00/B 02/W 32/W 11/B HDN 048 035/054 033/062 033/068 034/066 033/056 027/061 3/W 73/W 31/B 00/B 01/B 22/W 00/B MLS 044 030/045 031/057 033/062 031/057 030/048 028/057 3/W 74/W 21/B 00/B 11/B 22/W 10/B 4BQ 043 030/047 032/057 031/066 032/059 031/048 028/059 4/W 53/W 21/B 00/U 01/B 22/W 21/B BHK 045 025/038 026/050 030/056 026/047 024/043 024/053 1/E 65/W 21/B 01/B 11/E 23/W 21/B SHR 049 035/050 032/056 030/064 034/061 034/052 029/058 2/W 33/W 42/W 00/U 00/B 22/W 10/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS  FXUS65 KBYZ 131005 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 305 AM MST Mon Feb 13 2017 .SHORT TERM...valid for Tdy and Tue... Upper ridge seen early this morning along the BC/Pacific NW coast on water vapor imagery, will push inland today and slide gradually SE across the region through Tue. night. The ridge will bring dry and warmer weather, with windy conditions from KBIL W Tue. night. The models continued to bring some weak energy S along the MT/Dakotas border tonight, but moisture had decreased since last night's runs, so will keep the forecast dry. For temperatures, today's airmass will be similar to yesterday's, so have gone with similar high temperatures. 850 mb temperatures increase to +4 E to +8 degrees C W on Tue., so expect temperatures to be a few degrees higher than today's readings. Will leave the FLS for the ice jam on the Musselshell alone. This can be evaluated again today. Arthur .LONG TERM...valid for Wed...Thu...Fri...Sat...Sun... Extended forecast continues to looks mild and relatively dry through the week. An amplified upper ridge sits right over the forecast area on Wednesday. This ridge gets flattened and pushed east on Thursday by a fragmented shortwave trough moving in from northern California. Surface pressure gradients tighten up over the west for increasing winds over the western valleys. Wednesday night into Thursday morning should be the windiest times and based on guidance, bumped winds up from Livingston to Big Timber. May very well be advisory levels winds for this event, so will issue a HWO and supportive wind graphic. Have started PoPs a little earlier and painted low chances over the west early in the day Thursday. Spread these PoPs east Thursday afternoon and night. Energy swings north of the area Friday, so expect drying then. There will be another shot of precipitation Saturday with the next shot of energy moving up in southwest flow. Temperatures looks mild with the coldest air locked to the north. The precipitation on Thursday and Thursday night looks like a mix of rain and snow, as does Saturday. One note, the ECMWF was closing off a low over southeast Montana Sunday night, while the GFS was way farther south. Should the ECMWF verify, this could be a potentially significant storm system to impact the northern parts of southeast Montana. We will monitor that period closely. TWH && .AVIATION... VFR conditions will be over the forecast area again today. Winds will not be as strong as yesterday, but a few gusts to 20kts can be expected from KLVM to KBIL. TWH && .PRELIMINARY POINT TEMP/POPS... Tdy Tue Wed Thu Fri Sat Sun ------------------------------------------------------- BIL 044 024/047 029/057 036/058 035/052 028/048 031/047 0/N 00/U 00/N 00/N 22/W 01/B 22/W LVM 048 022/051 028/053 037/054 033/050 028/048 030/047 0/N 00/U 00/N 00/N 23/J 02/W 22/W HDN 044 019/047 022/054 024/054 030/049 026/045 025/045 0/U 00/U 00/U 00/U 22/J 01/B 22/W MLS 042 022/045 024/052 029/055 032/051 027/046 029/044 0/U 00/U 00/U 00/U 12/W 01/B 12/W 4BQ 045 021/048 025/055 031/058 032/052 028/048 031/048 0/U 00/U 00/U 00/U 02/W 00/B 12/W BHK 040 023/043 025/052 028/055 030/051 026/046 028/046 0/U 00/U 00/U 00/U 02/W 10/B 12/W SHR 045 019/048 024/058 027/058 029/051 025/049 028/046 0/U 00/U 00/U 00/U 22/J 00/B 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings