Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/15/21

Area Forecast Discussion
National Weather Service La Crosse WI
745 PM CST Thu Jan 14 2021 .UPDATE...Tonight Issued at 739 PM CST Thu Jan 14 2021 Based on model and radar trends, forecast snowfall amounts have been increased along and east of the Mississippi River into the 3 to 6 inch range. Meanwhile, snow totals in southeast Minnesota in the Winter Storm Warning area were decreased into the 6 to 8 inch range due to less snow expected tonight. As the dry slot moves into the area overnight, the snow will quickly diminish or end from the southeast. This should occur at KLSE and KRST between 15.07z and 15.09z. && .SHORT TERM...(This evening through Friday) Issued at 201 PM CST Thu Jan 14 2021 Messy winter system continues to impact the region early this afternoon, with warm air aloft leading to more of a wintry mix west of the Mississippi River this morning and dry air preventing much from falling to the east. Early afternoon surface observations showed a surface low over far southeast Minnesota/far northeast Iowa. While we`re going through a bit of a precip lull currently, expect an uptick in coverage and intensity as we go through the afternoon. As said low deepens through the afternoon, expect a cold conveyor belt to start ramping up, bringing in higher PWAT air from the east. In addition, short term guidance is in good agreement of some stronger frontogenesis and a TROWAL providing plenty of lift for an enhanced band of snow to form west of the Mississippi River and pivot over the I-90 corridor. Unfortunately, it does look like the timing of the band will impact the evening commute, especially near and just west of the Mississippi River. While 14.12Z HREF guidance doesn`t show particularly high chances for 1" per hour rates in this band (30-50 percent), would expect at least some spots within the band to see those rates, especially given the aforementioned forcing beginning to show up in the latest guidance. The surface low looks to move southward tonight with dry air wrapping around it and into much of the forecast area overnight. This will lead to snow lightening up or stopping completely for much of the area. How far north and west the dry air makes it through Friday morning remains a large question and will impact snowfall totals quite a bit. That said, short term guidance is in reasonable agreement that snow continues over the northwest half of the forecast area (roughly a line including Charles City, IA and La Crosse). To the southeast, CAMs do suggest the potential for some light precipitation in the dry slot and RAP soundings are trending toward a deep enough saturated layer for some freezing drizzle or very light snow, pending presence of in cloud ice. That said many other pieces of guidance are much shallower with the low level moisture and weaker with the lift, which would result in a dry period. For now keeping low precip chances in the forecast. On Friday, the low will slowly push south/southeast with light snow filling back in across the area. When all is said and done, expect highest amounts of around 6 to 10" in southeast Minnesota where they will receive the longest duration of snowfall and also be impacted by the heavier band this evening. Elsewhere, totals are expected to range from around 2 to 6 inches. Again, amounts will really depend on how much of lull we see tonight. In addition, surface temperatures right around freezing may prevent sticking at the onset of snow, especially in river valleys, so snow totals may be lower in those areas. Overall, totals did come down a bit, owing to said warmer surface temperatures, as well as expected lower snow/liquid ratios (right around 10 to 1). Still, with the anticipated higher snowfall rates with the band tonight, do still look like we should reach winter storm warning criteria, or at least be very close, so not adjusting any headlines. .LONG TERM...(Friday night through Thursday) Issued at 201 PM CST Thu Jan 14 2021 Our winter storm will slowly depart into the Ohio Valley Friday night with some lingering light deformation band snow across the area, but little to no additional accumulation. Can`t rule out some patchy freezing drizzle in spots overnight as the column desaturates aloft. With persistent cyclonic flow over the region, forecast soundings certainly show possibility of flurries into Saturday, especially east of the Mississippi River. Slightly better snow chances look to arrive heading into Saturday night and Sunday with a weak shortwave dropping through the area. Plenty of GEFS and EPS members show an area of light snow working southward across the area, so will retain small precip chances in the forecast. Certainly not looking like any appreciable snowfall out of this weak feature, likely just an inch or less mainly near and west of the Mississippi River. Temperatures will cool a bit over the weekend but will still remain above normal for mid-January. High pressure drifts over the region Sunday night into Monday, and then a clipper system is progged to drop somewhere into the region later in the day. Plenty of model spread in whether this system remains a quick-hitting, sheared out wave aloft or whether it develops into a slower-moving, deeper wave with impacts lingering into Tuesday. As such, just relied on a blend for now which yields slight chance PoPs for a portion of the area. Will continue to monitor this feature. Models diverge more late in the period but there is some potential for a Panhandle Low ejecting into the Ohio Valley or Great Lakes region by Thursday. Very low confidence on track this far out and whether it might eventually impact part of the area, so another feature we`ll just continue to monitor. Temperatures next week look to sit near or just above normal. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 529 PM CST Thu Jan 14 2021 A band of moderate to heavy snow is expected to move northward toward the Interstate 90 corridor early this evening and then stay in the region through 15.08z. Hourly snow rates look to be in the 0.5 to 1 inch range. One new development in the HRRR is that the heaviest snow looks to stay mainly in Wisconsin. We will continue to monitor this to see whether this trend continues before making too many changes to the KRST TAF. A dry slot looks to move into KLSE around 15.08z. This may result in the remainder of the TAF period for KLSE. As far as KRST, we will have to monitor where the FGEN band forms for late tonight and Friday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory until 6 PM CST Friday for WIZ017-029- 032>034-041>044-053>055-061. MN...Winter Weather Advisory until 6 PM CST Friday for MNZ088-095-096. Winter Storm Warning until 6 PM CST Friday for MNZ079-086-087- 094. IA...Winter Weather Advisory until 6 PM CST Friday for IAZ008>011-018- 019-029-030. && $$ UPDATE...Boyne SHORT TERM...CA LONG TERM...Kurz AVIATION...Boyne
Area Forecast Discussion
National Weather Service Pueblo CO
845 PM MST Thu Jan 14 2021 .UPDATE... Issued at 822 PM MST Thu Jan 14 2021 Overall, no big changes to the forecast for tonight, and no big changes to the headlines for Friday. However, did make some upward adjustments to the winds and gusts. Upper level system will continue to spin over the central CONUS, with the western edge still impacting parts of CO tonight into Friday afternoon. While winds will remain gusty over the area, the stronger winds will be situated to the east for much of tonight. Winds and gusts still on track to quickly increase early Friday morning, and did think about starting the High Wind Warning slightly earlier. At this time, any timing differences look to be small, but will continue to monitor tonight as it is possible for winds and gusts to strengthen sooner especially across Kiowa County. Latest RAP analysis showing some rather strong winds, 50-75kt, not too far off the deck over the Central Plains. As the 700mb low slightly retrogrades later tonight into Friday morning, will see these stronger speeds pivot back over the far eastern plains of CO. With tightening pressure gradient and mixing Friday morning, will see speeds/gusts really ramp up from early to mid morning. Given those speeds currently in place, expected trends with the pattern, and with model soundings showing these speeds in place over the far eastern plains by tomorrow morning, did increase winds and gusts. Have mentioned of northerly gusts up to 65 mph, but I am a little concerned there could be some occasional higher gusts during the mid morning time frame. Didn`t want to go too high at this time, but don`t think a few gusts in the 70-75 mph range would be out of the question. Will continue to monitor trends tonight and adjust as needed. It does look as if windier conditions will be present to the west of the current High Wind Warning, however, not enough to support expansion of the current headline. Strongest winds and gusts will occur through midday, but should begin to see a downward trend by early Friday afternoon, though still remaining on the strong side. && .SHORT TERM...(This evening through Friday) Issued at 242 PM MST Thu Jan 14 2021 .SHORT TERM...(Tonight and Friday) ...One more day of wind, then add enhanced fire danger... Currently...The strong upper low pressure system located over Iowa and the Dakotas has created strong north to northwest winds across much of the forecast area today with many locations reporting gusts of 40 to 50 mph. Winds have been much stronger across the higher elevations, but most sites save for the far eastern plains have struggled to reach high wind criteria. Mt wave cirrus shield from earlier today has finally dissipated, and temps at most spots have only warmed into the 30s and 40s. Tonight...The upper low moves very little tonight, as a H7 80kt jet sits overhead. However, high res models are indicating that the lower levels should decouple this evening and weaken, especially along the I-25 corridor. Under clear skies, look for very cold temps overnight along the corridor as well as the San Luis Valley. Elsewhere, across the far eastern plains as well as the higher terrain, winds will stay elevated for much of the night and minimum temperatures will be more moderate. Expect lows in the 20s along the eastern border, in the teens along the I-25 corridor and Upper Arkansas River Valley, and 5 below to 10 above for the San Luis Valley. Tomorrow...Similar set up for tomorrow as the upper jet laying across the region mixes down to the surface, and decided to issue another high wind warning for those spots closest to the eastern border starting at 5 am. Winds there are expected to increase to 30- 40 mph, with gusts up to 60 mph possible. The upper low center pulls to the east enough that the focus area for the stronger winds should slide out of the I-25 corridor, and since those areas did not meet criteria today, felt safe in leaving them out. However, it will still be windy tomorrow all areas. Also went ahead and issued a Red Flag Warning for Kiowa, Bent, Prowers and Baca counties. Those areas will have the strongest winds as well as the driest air, so critical fire weather conditions are anticipated starting at 10 am and lasting until 5 pm. After 5 pm models show the strongest winds overhead will have moved east, and with the short days, high wind conditions as well as critical fire weather conditions will ebb. Look for high temps in 40s tomorrow for the plains, and 30s for the high valleys. Moore .LONG TERM...(Friday night through Thursday) Issued at 242 PM MST Thu Jan 14 2021 The pattern will start to become somewhat more active through this long term period as several disturbance will be moving through and an active jet pattern will be over the region. Additionally, with the jet over us, temps will are expected to at or around seasonable values through this period. Based on current guidance, the best chance for meaningful precip will occur during the Tuesday time frame as a rather stout short wave is fcst to drop south across the Great Basin, and favorable upslope flow is fcst to develop over the region. The potential problem with this fcst scenario is if the short wave drops south too far west, and then the chance of precip will not be so favorable over the region (on the other hand if it moves a bit farther east then we will see better upslope over our fcst area). For now, the ensemble guidance is showing nearly all members with some precip over the region during the Tuesday time frame. Other short waves are fcst to move across the region during this period. A weak wave will move across the during the Saturday time frame and this will likely bring some light snow to the mountains during this time frame. Later in the week things may continue to be active as a long wave trough is likely going to push through. How this trough come through and how amplified it will be still is uncertain, but it will likely continue cool and unsettled later in the week. As for temperatures, given the jet pattern over the region temps will remain at or around seasonable through this period. Tuesday will likely be the coolest day. /Hodanish && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 242 PM MST Thu Jan 14 2021 VFR conditions will prevail for all locations throughout the forecasted period. The tightening of the gradient with the low pressure system that is propagating southeastward to the northeast will provide strong and gusty winds this evening, so some light to moderate CAT could be possible, especially east of the Rampart Range and further eastward over the plains. Winds will decouple later this evening and remain strong and gusty over the mountain ranges and along high mountain canyons and passes throughout the night. These winds will begin to percolate back to the surface by 17Z tomorrow and become strong and gusty and even stronger in the northeastern portion of the CWA by tomorrow afternoon as a significant jet maxima at the 700mb level of 75-85kts sets up over this area, so expect even some moderate or even possibly severe CAT to be present again from 17Z to 00Z if flying below FL100 over this portion of the CWA. Winds will increase over 20kts from the surface up to FL020 due to this jet maxima aloft, therefore there will be LLWS (Speed sheer) present for COS from 17Z throughout the remainder of the forecasted period. && .PUB WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 5 AM to 5 PM MST Friday for COZ095>099. Red Flag Warning from 10 AM to 5 PM MST Friday for COZ234>237. && $$ UPDATE...RODRIGUEZ SHORT TERM...MOORE LONG TERM...HODANISH AVIATION...STEWARD
Area Forecast Discussion
National Weather Service Riverton WY
354 PM MST Thu Jan 14 2021 .SHORT TERM...This evening through Friday night Issued at 150 PM MST Thu Jan 14 2021 After a varied weather day yesterday with record high temperatures in spots and winds in excess of 60 mph, today is much quieter. It is still quite windy, especially over Johnson County where a High Wind Warning remains in effect until 5 PM this afternoon. While it is less windy than yesterday, expect many areas to continue gusting to over 40 mph at times until around sunset. MOS data show winds diminishing in most places by around this time, with some areas still lingering into the evening hours. The current pattern over the CONUS is highly amplified with a deep trough carved into the Plains and MS Valley and a closed low near the Quad Cities. In the west, an area of high pressure is centered off the California coast southwest of Point Conception. In between is a tight gradient with a strong northerly to northwesterly flow. This is the flow that is currently over Wyoming. This should allow for dry conditions through the rest of the day, under a good deal of sunshine. The only exception would be over the Bighorns and Absarokas, where some lingering snow showers may be around through the afternoon hours. The aforementioned trough is projected to move eastward slowly throughout the period, allowing the winds to finally lessen. With winds diminishing tonight and the absence of much cloud cover, low temperatures should be seasonably cold with some below zero readings over the western mountains and single digits to teens elsewhere. The ridge becomes more oriented west to east tomorrow with the axis forecasted to be over the CWA around 00Z Saturday. Therefore, expect the daylight hours Friday to remain dry with temperatures several degrees warmer over the mountains and other areas being similar to today. By the time tomorrow night comes, models show a shortwave trough moving through the overall ridge pattern. Some light snowfall is possible with this feature, mainly over the western mountains and the Bighorns. It is not out of the question that southeast Sweetwater County may also see some snow, as the HRRR puts out an area of precipitation from Rock Springs to Wamsutter at 09Z and 12Z Saturday. MOS data shows just under 20 percent PoP on the NAM from 06-12Z for Rock Springs, so confidence is low on anything of significance over this area. Expect accumulations up to an inch over the Tetons and near Yellowstone and, possibly, one to two inches over the Bighorns. .LONG TERM...Saturday through Thursday Issued at 150 PM MST Thu Jan 14 2021 Any leftover snow from the Friday night system should be ending Saturday morning, with mainly dry conditions with transitional ridging and surface high pressure building into western Wyoming. These dry conditions should hold through Saturday night and into Sunday morning. The next Pacific trough then moves into northwestern Wyoming for Sunday afternoon and crosses the state through Monday. Both the ECMWF and GFS are in fairly good agreement with keeping the chances of precipitation across the area through Monday night. Both models also favor northern Wyoming for the heaviest QPF. There are some differences in the details however. The GFS is somewhat further south with the best forcing and has heavier QPF, especially in eastern areas. Meanwhile, the ECMWF keeps the system a bit more disorganized with the best forcing to the north across Montana. As a result, confidence on any snowfall amounts remains low at this time. Still time to watch it though, as it is still 3 days out. Shortwave ridging should then bring mainly dry conditions for Tuesday. Uncertainty then gets cranked up to 11 for the evolution of the possible next system for midweek. The models continue to be undecided on the effect of an upper level low near California and that will be the determining factor. The models also continue to show very poor run to run consistency. For now, we kept things mainly dry with snow mainly over the mountains until there is more model agreement. && .AVIATION...For the 00Z TAFS through 00Z Saturday VFR conditions are expected at all terminals through the TAF period. Strong west to northwest wind observed this afternoon across much of the area will weaken this evening. Most locations will generally have light winds by around 06Z. The exception will be breezy westerly winds will remain at KRKS through the TAF period. A few snow showers over the northern mountains, pushing into the adjacent lower elevations, will be ending at the beginning of the TAF period. Patchy morning fog across the far western valleys is not out of the question, but overall boundary layer moisture looks a bit dry for anything widespread. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued at 150 PM MST Thu Jan 14 2021 Expect windy conditions to continue for the afternoon hours, making for good conditions for any smoke dispersal. Temperature inversions may set up tonight for basin areas with a mainly clear sky and light winds. Dry conditions are expected for the day Friday. Some snow may return to the western mountains and Bighorns Friday night/Saturday morning. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 5 PM MST this afternoon for WYZ010. && $$ SHORT TERM...Clayton LONG TERM...Hattings AVIATION...Murrell FIRE WEATHER...Clayton