Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/03/18

Area Forecast Discussion
National Weather Service Gaylord MI
1047 PM EST Fri Feb 2 2018 .UPDATE... Issued at 958 PM EST Fri Feb 2 2018 A healthy lake effect snow band has been clipping the Whitefish Pt area for a few hours since late afternoon, but that band is now lifting just north of there. It will hover in that vicinity for the next several hours, then get dragged back southward again as winds veer. That won`t last long before 1000-850mb winds collapse toward morning as the pressure gradient is disrupted, killing the band entirely. Still, have bumped of snow amounts tonight north of Paradise. Elsewhere, very light lake effect snows are just starting to respond to an influx of mid-level moisture. Areal coverage has increased considerably near and north of M-32. Intensity is also on an upward trajectory, though slower. QPF progs in far northern lower MI from the hi-res guidance are generally unimpressive, less than a tenth of an inch thru 12z. Might be able to slightly tweak snow amounts down over far northern lower. However, guidance is more bullish on breaking out snow showers in the rest of nw lower MI overnight (especially near and s-sw of TVC). Nam is probably excessive in breaking out almost 0.20 of liquid near Wellston by late morning, but the HRRR and Rap both argue for 1-2" snow accums even before the advisory kicks in down there. Given that a headline is already up, there`s no good reason not to accelerate the start time to cover late-night and early- morning lake effect. Will go ahead and do that. && .NEAR TERM...(Tonight through Saturday) Issued at 307 PM EST Fri Feb 2 2018 ...Lake snows give way to widespread snow to start the weekend... High impact weather potential: Widespread accumulating snow likely by the end of Saturday, heaviest in the traditional snow belt regions. Pattern synopsis/forecast: Broad troughing remains overhead, and looks to remain locked in place for the next several days. Attendant cold air drop within this trough axis continues to kick off lake effect snow showers, albeit of lighter intensity than experienced the last day or so as dry air and shallow lake induced convective depths have taken their collective toll. Winds steadily backing through the day have spread the wealth, so to speak, but once again with minimal accumulations. Attention through the near term focused on dual upstream waves, the lead of which is punching rapidly southeast across northern Minnesota, with the other way back across Alberta. Initial wave will rejuvenate the lake processes tonight, while the latter looks to drum up a widespread light to moderate snow event Saturday and Saturday night. Primary forecast concerns/challenges: Snow amounts and attendant headline decisions remain the primary forecast concerns. Details: One complicated forecast with regards to snow evolution (and amounts) tonight and Saturday. Minnesota wave arrives quickly this evening, bringing enhanced moisture along with it. While the lake induced convective boundary layer remains fairly shallow, a developing seeder-feeder mechanism in an increasingly favorable thermal regime should support a reorganization and intensification of lake snows. Wind speeds do decrease later tonight, which may partially inhibit moisture flux off the big waters. Winds continue to slowly back to a west/southwest direction, focusing best enhancement along the Lake Michigan Coast and up into some of the Tip of the Mitt counties. Still thinking an additional 2 to 4 inches of snow tonight in those favored areas. But...more snow to come Saturday with arrival of that second wave. Initial shot of warm air advection gives way to transient fgen forcing and broad deformation, all within a slowly deepening moisture field (precipitable water values up near a quarter of an inch). Still looking at a touch of lake enhancement in southwest flow areas, although modifying thermal profiles and increasingly disorganized wind fields likely preventing things from getting too out of hand. System snow itself will deliver, especially across northern lower Michigan. Expect an additional 1 to 4 inches, heaviest closer to Lake Michigan. Isolated higher amounts are possible, especially if fgen forcing can become stationary for any length of time. Good news is wind speeds will remain light, negating any blowing or drifting snow concerns. More snow expected Saturday night. See short term section below for that information. Headline Management: After in-house coordination with short term forecaster and coordination with surrounding offices, have introduced a winter weather advisory for much of northwest lower Michigan, beginning tonight/Saturday morning, running into Sunday morning. Possible more counties will need to be added at a later time. && .SHORT TERM...(Saturday night through Monday) Issued at 307 PM EST Fri Feb 2 2018 ...Snowy Weekend... High Impact Weather Potential...Snow from a storm system and lake enhancement/effect Pattern Synopsis/Forecast...The ridge/Trough pattern at 500 mb has returned over the Upper Great Lakes, and expected to continue over the region through the next weekend. So the details over the weekend will be that of the sfc low/500 mb shortwave trough rotating through the region producing light to moderate amounts of snow for Saturday night, then lake effect snow Sunday and into Sunday night. Monday has lake effect, but from the SW and starts as lake effect, but begins to transition into system snow into Monday. Primary Forecast concerns...The system snow is pretty straight forward, so the amounts look okay. Had to blend the snow ratios(SLR) a bit with the WPC guidance for SLR, as the model consensus numbers were a bit on the high side for the system snow. Then transitioned into the 20+:1 rations Sunday as we get into the LES with the colder 850 temperatures (-18c to -20c). Monday, SREF and GFS show WSW flow snow les, but the 850 mb temperatures support it, but the 850-700 mb layer rh is a bit on the dry side. so would expect minor to light amounts. .LONG TERM...(Monday night through Friday) Issued at 307 PM EST Fri Feb 2 2018 ...Continued Below Normal Temperatures and Periodic Snow... Extended (Monday night through Friday)...As mentioned in the pattern section of the short term section above, the 500 mb low stays north of the forecast area, and keeps us in the trough into next weekend. This will bring us below normal temperatures, and periodic chances of snow/snow showers as a low will move through and bring system snow, then on the back side, lake effect snow showers until the high dries out of the region briefly for it to start over again. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1047 PM EST Fri Feb 2 2018 Snow to intensify late tonight into Saturday. Mostly VFR with some MVFR conditions out there presently (mainly PLN), with light lake effect snow showers. An incoming low pressure system will reach southern WI by Saturday evening. System snow and lake effect will to be re-invigorated late tonight and especially Saturday. IFR conditions will arrive at MBL/TVC/PLN on Sat morning, and APN in the afternoon. Current west winds will back southerly tonight and Saturday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY from 4 AM Saturday to 9 AM EST Sunday for MIZ020-025>027-031>033. WINTER WEATHER ADVISORY until 7 AM EST Sunday for MIZ016-017-019- 021-022. && $$ UPDATE...JZ NEAR TERM...MB SHORT TERM...JL LONG TERM...JL AVIATION...JZ
Area Forecast Discussion
National Weather Service Cheyenne WY
339 PM MST Fri Feb 2 2018 .SHORT TERM...(This evening through Saturday night) Issued at 235 PM MST Fri Feb 2 2018 Main focus will be on winds in the wind prone areas as well as the expected heavy snowfall over the higher mtns through Saturday. Winds around the Arlington area as well as the summit have edged up this afternoon and a couple locations hitting high wind speeds. Expect this trend to continue while spreading a little more so have upgraded the watch to a warning. Winds still look like they will ease some tomorrow morning before likely rising again by late in the day as 7H winds increase to around 50kts along with decent downward motion over the S. Laramie Range. Will also have to watch areas such as the Laramie Valley for some stronger winds if sufficient mixing occurs. Moist nwly flow will keep snow going over the higher mtns through Saturday night, likely heaviest later this evening into Saturday, aided by a passing shortwave in the flow. Next push of cold air arrives Saturday night with an areas of mainly light snow developing behind the front over the northeast part of the CWA. .LONG TERM...(Sunday night through Friday) Issued at 235 PM MST Fri Feb 2 2018 A general northwest flow aloft will keep the varying weather going across the area with periodic cold air surges and associated snows. Fairly widespread snow expected over the CWA early Sunday as the front banks up against the mtns but the snow should end fairly quickly Sunday afternoon as the surface high dives rather quickly southeast over the central plains and upslope flow is lost. Could be a band of moderate snowfall over the northern parts of the CWA Sunday morning so will have to watch. Front quickly backs out Sunday night with a strong wind event shaping up again for the wind prone areas into Monday morning. The next surge of colder air then arrives late Monday with another round of mainly light snow behind it. Cool Tuesday before warming again for Weds and Thursday. Unsettled pattern persists for late in the week as the next surge of cold air drops out of Canada into the region Friday bringing the next chance for snow. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 337 PM MST Fri Feb 2 2018 VFR conditions for airports east of Laramie Range the next 24 hours. Looking at some snow to develop west of the Laramie Range tonight that could impact KLAR and KRWL with lower flight conditions for a time tonight. Latest HRRR hitting KRWL the hardest with IFR conditions after 08Z. Generally followed its guidance for the 00Z TAFs. && .FIRE WEATHER... Issued at 235 PM MST Fri Feb 2 2018 No fire weather concerns expected into at least early next week. There will be periods of gusty/strong winds but cool temperatures and resulting RH well outside of critical thresholds. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Storm Warning until noon MST Sunday for WYZ112-114. High Wind Warning until 5 AM MST Saturday for WYZ110-116. High Wind Warning from 8 PM this evening to 5 AM MST Saturday for WYZ106-117. NE...None. && $$ SHORT TERM...RE LONG TERM...RE AVIATION...GCC FIRE WEATHER...RE
Area Forecast Discussion
National Weather Service Grand Forks ND
704 PM CST Fri Feb 2 2018 .UPDATE... Issued at 658 PM CST Fri Feb 2 2018 Light snow area moving SSE into Grand Forks/Thief River falls and will move into Bemidji soon. Nothing impactful with trace to a couple tenths. Will keep a mention of -sn thru the evening in NE ND and NW MN. Next stronger system moving quickly southeast into eastern Washington state at 00z and will move southeast into the central Plains into Saturday. Sfc low with this feature will develop in Montana and move into southern South dakota or northern Nebraska. Light snow in Alberta and SW Saskatchewan will spread ESE thru the night across ND and parts of SD reaching E ND 06z and afterwards into NW/WC MN and ending Saturday morning. HRRR and RAP meso models have shifted a bit back southward with main snow and show best chances for 3 or so inches more from south of Minot to Fargo area... But a wide area of light snow so idea of a 1-3 inch snowfall still seems ok...but it is possible many spots in NE ND are on the lower end of current fcst range (2-3). Winds do increase Saturday from the north at 15-20 kts in cold advection and this will need monitoring. But appears winds to follow after the snow ends. && .SHORT TERM...(This evening through Saturday) Issued at 312 PM CST Fri Feb 2 2018 Snow and associated impacts the main concern for the forecast overnight into Saturday. Northwest flow afoft continues to bring embedded short waves across the northern plains. There is a current wave bringing light snow to the Roseau and Lake of the Woods area. The light snow will drift to the south into the late afternoon and evening. Minimal impacts with this event as an inch or so of accumulation is expected from light snow over several hours. Attention turns to the next wave into the overnight period as SFC low tracks from NW SD to SE SD during Saturday. As it moves southeast early Saturday morning snow will spread from northwest to southeast across the area with Pwats increasing to near a quarter inch. Frontogentical forcing translates quickly across the forecast area with strongest synoptic forcing displaced north across Manitoba. Expecting some disorganized and transient bands developing and diminishing through the overnight. Given this environment expecting widespread 1 to 3 inches with possibly 4 plus inches if and where a stronger band sets up. Winds will turn towards the north and escort the next push of arctic air into the region Saturday afternoon. Blowing snow is not anticipated as winds remain below 20kts however some drifting snow can be expected Saturday afternoon. .LONG TERM...(Saturday night through Friday) Issued at 312 PM CST Fri Feb 2 2018 Main concern to start the period will be temperatures and associated wind chills. Surface ridging will build into the region overnight allowing temperatures to drop into the teens and twenties below zero. Although winds won`t increase until later in the day on Sunday, temperatures will be cold enough to produce wind chills within advisory criteria (possibly pushing warning criteria across the far north). The dangerous wind chills will continue throughout the day on Sunday (even as temperatures warm) due to increasing westerly winds between high pressure to the south and low pressure further north. Sunday also has the potential to bring blowing snow and associated visibility issues if winds can get high enough (roughly 30+ mph) thanks to any fresh snow from Saturday. Following the weekend, cold high pressure looks to keep the region dry for the first part of the new work week. However, wind chills will continue to be a concern during the overnight and early morning hours for much of the area. Confidence remains low for any precipitation chances later in the period as model solutions diverge. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 658 PM CST Fri Feb 2 2018 Mix of MVFR/VFR cigs thru the pd...mostly in the 2500-4000 ft agl range. Winds turning northerly overnight into Saturday and light snow at times this eve GFK/TVF/BJI then more widespread and lower vsbys late tonight into Saturday morning. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Riddle SHORT TERM...JK LONG TERM...Lee AVIATION...Riddle
Area Forecast Discussion
National Weather Service Glasgow MT
647 PM MST Fri Feb 2 2018 .DISCUSSION... 630PM Update...With snow beginning to move into northeast Montana from the west and north this evening, the overall forecast looks to be in excellent shape. Only real change was to increase pops in the northeast a little earlier than previously forecast as snow is already being shown on radar across northern Valley county all the way east to Sheridan, and have also received reports of snow from Poplar. This snow is expected to increase in coverage throughout the evening, but should remain fairly light in intensity. Most of northeast Montana can expect 1 to 2 inches of snow tonight, then another round Saturday. This second round will be more intense across the western half of northeast Montana, with 3 to 6 inches of snow possible, and up to 8 inches would not be surprising in the Little Rockies. Of immediate concern is also the freezing rain/sleet potential. Latest near term models are very consistent with at least the possibility of freezing rain generally along a frontal boundary that will move across Petroleum and Garfield counties tonight with H850 temperatures up to 2 or 3 degrees Celsius above zero, and below freezing temperatures at the surface. This is also supported by the 1000 to 500mb geopotential thicknesses. With the SREF and RAP bringing above freezing temperatures aloft as far east as Prairie County, have no issues with leaving the Winter Weather Advisory as is. With the H700 and surface temperatures well below freezing, however, there is question as to how long this lasts with such a shallow warm layer to work with, so expect this to be limited to along or very near the frontal boundary. With recent reports of freezing rain in Havre and the potential impacts to roads and sidewalks any freezing rain would have, prefer to err on the side of caution and make no changes. Will keep an eye on things to see if we end up needing to expand the area of freezing rain in the forecast. Behind this system, another shot of cold air moves in tomorrow night. Will likely need either a Wind Chill Advisory or expand the Winter Weather Advisory for bitter cold wind chills Saturday night into Sunday, but will leave this for the overnight shift to take another look at and make that final decision. Previous Discussion: As a wave of pacific moisture overrides Arctic air residing into northeast Montana, expect light snow at times tonight. Latest 12z model guidance does have the warm nose aloft a little further northeast. Taking a look at Bufkit forecast soundings across the area as well as SREF probability of precipitation type products, the Winter Weather Advisory in effect looks good. Given the trend, the next shift will have to monitor locations a little further north and east. A transition to snow will take place Saturday and continue into Saturday night. Several inches of accumulation are likely, and this will create travel difficulties, especially if it obscures any icy surfaces that develop. For messaging simplicity, left the Winter Storm Watch in place for now, and the next shift can make any upgrade decisions as the existing advisory reaches expiration. Lastly, with a reinforcement of Arctic temperatures Saturday night and Sunday morning, wind chill concerns may result at times as well, and this will be another cause of impacts. Expecting northwest upper flow over the region for Sunday into early next week. The next wave of overrunning moisture looks to affect the southwest zones during this time with accumulating snow again possible. Given the focus on the near term impacts as well as considering how model spread increases at larger time scales, the forecast for the midweek onward was trended toward latest model consensus blends which maintains an unsettled weather pattern overall through the week. Maliawco && .AVIATION... IFR CIGS will prevail along with reduced visibilities in snow overnight and on Saturday. A little wintry mix is possible at times tonight as well near KGDV, though confidence is low on the northeastward extent. Expect northeast winds at 5 to 10 kts becoming north on Saturday at 10 to 15 kts. Maliawco / Hickford && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from 3 AM MST Saturday through late Saturday night for Central and Southeast Phillips...Central and Southern Valley...Daniels...Dawson...Garfield...McCone...Northern Phillips...Northern Valley...Petroleum...Prairie...Richland... Southwest Phillips...Western Roosevelt...Wibaux. Winter Weather Advisory until 3 AM MST Saturday for Garfield... Petroleum...Prairie...Southwest Phillips. && $$
National Weather Service Jackson KY
720 PM EST Fri Feb 2 2018 .UPDATE... Issued at 720 PM EST FRI FEB 2 2018 Surface high pressure is currently centered over the lower OH Valley region. At the same time mid level heights are expected to rise tonight with the sfc high working across the Appalachians with the center of the high over eastern VA and northeast NC by dawn on Saturday. Cu and stratocu have been dissipating with loss of sunlight with any remaining low clouds dissipating over the next few hours. Mid and high clouds will increase overnight, especially late. However, with dewpoints across the region near 10 above and many valley locations in the mid to upper teens the cold spots should easily reach 8 or 9 above overnight. Some ridgetop locations were also running colder than the previous forecast and some of the guidance so those locations were also cooled off a bit as well. Hourly temperatures have been updated accordingly with no other changes attm. && .SHORT TERM...(This evening through Saturday night) Issued at 330 PM EST FRI FEB 2 2018 20z sfc analysis shows high pressure moving steadily into Kentucky as low pressure and cyclonic low level flow departs southeast Kentucky. The low has held on fierce today, though, keeping lower clouds in the southeast along with some scattered light snow showers and flurries into the first part of the afternoon. Only now are the clouds clearing and the radar returns fading out. Temperatures did not recover much today from morning lows as northwest winds of 5 to 15 mph continued to advect in colder air. As such, afternoon highs were generally capped in the upper teens and lower 20s. Meanwhile dewpoints were mainly in the single digits. The models are in good agreement aloft through the short term portion of the forecast. They all depict a pattern adjustment in the wake of an eastern trough pulling out of the area switching mid level flow from northwesterly tonight to southwest flow on Saturday into Sunday morning. Embedded in this flow will be a developing trough and associated spokes of energy moving into Kentucky from the west Saturday night. At the same time a couple strengthening 300 mb jet streaks will interact over eastern Kentucky with a healthy pocket of divergence aloft and enhanced lift for our area late Saturday night. Given the model symmetry will favor a general blend, but lean most heavily on the higher resolution HRRR and NAM12 for weather specifics through the period. Sensible weather will feature a clear and cold night with good radiation expected owing to light winds and subsidence aloft. Further complicating the situation will be the disparate, and almost entirely elevation dependent, snow cover left from last night`s event. Expect the ridges to be the coldest due to the extra snow cover, but valleys should not do too bad either so have lowered min temperatures across the board tonight. For Saturday we will see quite a warm up as the winds switch to the south and increase ahead of an incoming warm front. This front brings another slug of moisture to eastern Kentucky later that night into Sunday morning with a dicey temperature profile. Best indications are that the pcpn will initially wetbulb to below freezing through the column resulting in a period of snow - perhaps mixed with a touch of sleet for a time late Saturday night into dawn Sunday. Generally, a half to one inch of snowfall can be expected from this. Will highlight this concern in the forthcoming HWO. Again used the CONSShort and ShortBlend as the starting point for all the grids with some complicated point based adjustments tonight for elevation and snow cover differences. As for PoPs, kept them low through 06z Sunday before ramping them up toward 12z. .LONG TERM...(Sunday through Friday) Issued at 255 PM EST FRI FEB 2 2018 The extended period will feature alternating periods of quiet and active weather across eastern Kentucky. The start of the period will feature periods of rain and snow showers across the area Sunday through Monday morning, as areas of low pressure moves slowly across the Great Lakes and Ohio Valley regions and the Tennessee Valley. A mix of rain and snow can be expected for most of the area on Sunday morning, with our far eastern Kentucky seeing all snow to start the day. The snow and rain snow mix should transition to all rain through out the mid and late morning hours, with everyone likely seeing nothing but rain by early Sunday afternoon. Snowfall amounts should average less than an inch for most locations, with the higher terrain along the Virginia perhaps seeing an inch or two of snow before all is said and done. After the precipitation finally comes to an end on Monday, we can expect a brief period of dry weather Monday afternoon and most of Monday night. Another area of low pressure, and its attendant surface cold front, area forecast to move across the region from early Tuesday morning through early Wednesday night. This system should bring scattered rain and snow showers to the area Tuesday morning, before temperatures warm enough for everything to transition over to all rain by early Tuesday afternoon. This system will not have the amount of cold air with it that its predecessors had, so only a rain snow mix is forecast for Tuesday night into Wednesday morning north of the Mountain Parkway. After a period of nothing but rain, it looks like another bit of cold air will make its way into the area, which will pave the way for snow mixing with rain by late Wednesday afternoon. This trend should then continue into Wednesday evening and Wednesday night, with a rain snow mix changing over to all snow across the area. This last bit of precipitation should be out of the area by late Wednesday night. Thursday and Friday should be dry, as a ridge of high pressure finally builds across the region. Temperatures on average should max out each day in the 40s, with the exceptions being Monday, when highs will likely not make it out of the 30s, and Tuesday, when locations along and south of the Hal Rogers Parkway may max out in the lower 50s. Areas north of the Mountain Parkway also may only make it into the upper 30s for highs, with lower 40s everywhere else on Thursday. Nightly lows should generally be in the 20s across the area. Tuesday night will be the outlier, with lows that night forecast to only fall into the 30s and 40s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 719 PM EST FRI FEB 2 2018 VFR conditions are occurring across the region with a few patches of stratocu around 2kft lingering over far southeast KY near the VA border. These should continue to dissipate through 3Z as surface and mid level ridging build across the area. The high will move east of the area later tonight and on Saturday with mid and high clouds gradually increasing and lowering from west to east between ahead of the next approaching system. Winds will be light and variable through tonight as the high moves across the area, becoming southerly at generally 10kt or less during the 12Z to 0Z period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...JP