Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/08/21

Area Forecast Discussion
National Weather Service Gaylord MI
650 PM EST Tue Dec 7 2021 .NEAR TERM...(Through Tonight) Issued at 343 PM EST Tue Dec 7 2021 ...Lake effect snow reinvigorates tonight... High Impact Weather Potential: Moderate. Accumulating lake effect/enhanced snow nw lower MI. High pressure is crossing southern IN/OH. 1013mb low pressure is over nw IA. This low will approach southern Lake MI by morning, though this low will tend to fill overnight, as cyclogenesis proceeds over northern MI. An initial, weak shortwave pushes from southern MN to central lower MI tonight, but a stronger wave digs across Superior tonight. The surface low reorganizes further north in response to that. A small area of synoptically-driven will continue eastward, just north of the original surface low. This would track into central lower MI late evening/overnight, tending to diminish with time as the original low deteriorates. The synoptic component to snowfall tonight will be negligible. But the low levels are abundantly cold (widespread temps in the teens) and potentially unstable. Lake effect snow should see a considerable resurgence with the added moisture, and a rather long sw fetch on Lake MI. 850mb temps of -13 to -15C will provide abundant instability, and a respectable DGZ (and at times max omega within it) to promote fluffier snowfall and higher snow-liquid ratios. Sw flow holds for most of the night, only veering w-nw over Lake MI toward 12Z. Have adjusted QPF and snow ratios higher. How much higher? Well, multiple runs of the HRRR have generated over an inch of liquid QPF on a small part of Emmet Co tonight. The HRRR is likely in general overdone, but sw flow events do get excessively exuberant on occasion over the tip of the mitt. Do have a small area of Emmet Co, between Harbor Spgs and Cross Village, getting up to 8" of fluffy snow tonight. Without much wind, and with a largely nocturnal event, a warning does not appear necessary. Have expanded the advisory a touch this afternoon, to include Charlevoix Co (where healthy snow is expected along the coast, including in the city of Charlevoix). Cheboygan Co was also added, though this was a tougher call; heavier snow amounts should only be in a small portion of nw Cheboygan Co, west of the city of Cheboygan. But this includes a decent stretch of I-75, and have elected to include largely for that reason. With increasing cloud cover, and low-level warm advection, temps won`t get an opportunity to fall too much. Mins will be mainly in single digits above zero in eastern upper MI, and in the lower to middle teens in northern lower. && .SHORT TERM...(Wednesday through Friday) Issued at 343 PM EST Tue Dec 7 2021 High Impact Weather Potential: System snow Thursday with precipitation-type issues Thursday night...additional system later Friday. Pattern Synopsis/Forecast: Morning surface analysis shows broad high pressure across the eastern CONUS...though Lake Aggregate troughing holds on across Northern Michigan, resulting in lingering lake effect snow here. Next system upstream is located over southeast South Dakota...associated with a trough axis aloft extending from Minnesota southwestward into the Lee of the Rockies. Thermal boundary at the surface is analyzed from this system back into southern Montana towards the Oregon/Washington coast. Thermal gradient aloft is tightening across Alberta this morning as ridging moves onshore...resulting in a stationary boundary analyzed over this same area...with a resultant upper level jet max as well, which will feed into the troughing across the central CONUS. By Wednesday morning...will look for trough axis to have moved nearly overhead...and continue to swing through through the remainder of the day. Ridging will be quick to move in behind it...ahead of a southern stream shortwave taking shape across the central/southern Rockies, with a resultant surface low ahead of it. This niblet will head northeastward along the flow...affecting us Thursday. Flow will amplify across the well as upstream over the Pacific...going through the day Friday. This will result in a deeper and more organized trough axis across the western central CONUS by late Friday...with another deep trough diving toward the Pacific coast of North America for the end of the short term...and beginning of the extended. Primary Forecast Concerns: Lingering snowfall Wednesday...return of snow and precipitation type issues Thursday?...ditto for Friday...gusty winds late week as well... By Wednesday morning...trough axis aloft should be poised just to our west/northwest...swinging across the CWA through the day...and taking much of any remaining mid-level moisture along with it. Will look for the surface reflection to be ahead of the trough axis aloft...with fropa likely taking place during the morning hours, resulting in NW flow behind the system. Would look for a potential band of snow to precede the front, given some potential upper level support along/ahead of the trough aloft...though the strongest signals for snow will remain across northwest Lower Wednesday morning. Currently doesn`t look like there`ll be a ton of wind with this (thankfully), which should help keep any lingering lake effect behind the system closer to shore. Does appear that inversion heights fall through the day as we lose mid-level moisture...but, like trying to brake in the will take longer to put the stop on the lake effect machine than we may expect. Guidance points toward some potential NW flow convergence across Eastern Upper through the day...which is something we`ll have to keep an eye on, particularly with somewhat better instability up that way. Once surface high pressure passes by Wednesday night (which could result in a chilly night for some areas that stay clear to mostly clear with lighter winds...), will look for southerly flow to return and strengthen for Thursday ahead of the next system, related to a couple niblets of energy in the flow ahead of larger-scale troughing across the western/central CONUS. As deeper moisture returns to the Great Lakes ahead of this system on strong southerly flow...will look for some warm advection precip to spread into the area ahead of a weakening surface low in broader surface troughing extending northward to a surface low in central Manitoba. This surface trough/cold front will swing through Thursday into Thursday night ...lending to additional synoptic support for combination with an approaching upper level jet max. Attm...deepest moisture looks to be a little further north with this system, closer to the UP and Tip of the Mitt...but will have to watch this in the next day or two to see if anything changes. Looks like this will likely be focused later in the afternoon into early Thursday night, with guidance perhaps a touch quicker than previously. With warm advection comes potential for p-type will have to keep an eye on that as well. Additionally...with the warm advection aloft...and a deep mid-level dry layer Thursday evening/night, but saturated low levels possible up to around 850mb...may have some freezing drizzle concerns to contend with. Going into Friday...the column begins to saturate again from the top down ahead of a more substantial system developing out in the central/southern Plains. This will remain a tricky guidance continues to track this system through the Great Lakes, though recent model trends seem to indicate a further south and east track. This suggests we may have more frozen/mixy crud to deal with, as opposed to the primarily rain situation we`d have if it were further north...though there is still a fair amount of uncertainty in the exact track and timing attm. Will have to watch this it will bring a conglomeration of potential impacts to the area...including mixed precip and gusty winds, in addition to higher-moisture-content synoptic snow...all of which will be dependent on where the system tracks. Currently...may be dealing with a bit of a calm-before-the-storm situation early Friday...with the biggest impacts perhaps holding off till later in the day/evening...but will have to see how timing trends play out in the coming model runs. .LONG TERM...(Friday night through Tuesday) Issued at 343 PM EST Tue Dec 7 2021 High Impact Weather Potential: Moderate...potential system Friday night into Saturday... Pattern Synopsis/Forecast: Aforementioned deep and organized trough axis will swing across the central CONUS Saturday...with a strong upper level jet max ahead of it. Synoptic moisture will advect in from the south on Friday night into Saturday ahead of the surface low. An abundance of upper level support looks to be in play with this a strong upper level jet passes through the flow. As mentioned above, at the end of the short term...will have to keep an eye out for some p-type issues, as warm advection should cause us to flirt with some warmer temps aloft. Either way, it should be rather unpleasant Friday night into Saturday. As we get in behind the system on Saturday night into Sunday, with some wraparound moisture on the backside of the system...and some colder air aloft moving in...will look for lake effect potential to return to Northern Michigan. Beyond Saturday...will be watching the pattern turn more ridgy across the CONUS/eastern CONUS going into the start of next week. May have to watch out for some niblets trying to pass through the flow at times, with some uncertainty in how strong the ridge will ultimately end up being. That being said...temperatures will probably become the main story going forward, unless signals dampen in the next few days. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 646 PM EST Tue Dec 7 2021 Lake enhanced snow will continue to increase at PLN, MBL and TVC overnight into Wednesday morning before waning by afternoon. Cigs/Vsbys will be mainly MVFR but IFR vsbys are possible at times. At APN only a few flurries are expected. Generally low end VFR cigs/vsbys are then expected Wednesday afternoon. Winds will be light and variable through early Wednesday then pick up and be a bit gusty out of the northwest Wednesday morning and afternoon. && .MARINE... Issued at 343 PM EST Tue Dec 7 2021 High pressure is passing to our south today, with winds decreasing somewhat as they back toward the sw. Sw winds linger into tonight, though will start to veer nw toward morning, as low pressure develops over northern MI. Relatively light nw to w breezes hold for Thursday and Thu night. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY until noon EST Wednesday for MIZ016-017- 020-025-031-099. LH...NONE. LM...NONE. LS...SMALL CRAFT ADVISORY until 5 AM EST Wednesday for LSZ321. && $$ NEAR TERM...JZ SHORT TERM...FEF LONG TERM...FEF AVIATION...AS MARINE...JZ
Area Forecast Discussion
National Weather Service Goodland KS
313 PM MST Tue Dec 7 2021 .SHORT TERM...(This evening through Thursday) Issued at 215 PM MST Tue Dec 7 2021 At the beginning of the short term period, current RAP analysis shows the CWA having a west-northwesterly flow aloft while there is an upper air ridge over the Pacific Northwest and an upper air low just off the coast of central CA. By tonight, the front part of the ridge is expect to make it over the CWA turning the flow over the CWA north-northwesterly overnight. At the surface, dry conditions look to continue across the CWA. Winds look to be light and variable through the remainder of the afternoon and turn southerly at 5 to 10 mph by the evening hours before transitioning to more west- southwesterly overnight. Daytime temperatures do not expect to pass over the 50 degree mark before beginning to cool with overnight lows between the upper teens and lower 20s. On Wednesday, the ridge makes it over the CWA during the day while the aforementioned upper air low opens up into a trough in the southwestern CONUS. By the evening hours, the trough is expected to weaken while moving towards the CWA turning the flow aloft southwesterly. Overnight, models show a zonal upper air flow looks over the CWA. At the surface, dry conditions continue while a lee surface trough is expected to develop over the Front Range due to the pattern aloft that moves through the CWA during the evening hours. With this surface feature, winds on Wednesday expect to blow from the south at around 15 to 20 mph with gusts up to 30 mph possible during the day. Winds expect to slow to 5 to 10 mph and turn westerly late by the evening hours. Daytime high temperatures on Wednesday expect to range between the middle 50s and the lower 60s with overnight lows in the middle 20s to lower 30s. For Thursday, the next weather maker for the area starts to develop thanks to an upper air trough in the Pacific Northwest. Models show this trough strengthening and moving eastward throughout the day with its front part reaching over the CWA late Thursday turning the flow aloft southwesterly again. At the surface, models show a surface low developing in central CO during the day with this pattern aloft and slowly moving eastward over the CO/KS border by Thursday night. As mentioned in the previous short-term forecast discussion, models still continue to show most of the CWA in the warm sector of the system overnight though the position of the low looks to have moved slightly southward. With this setup, northwestern Yuma county looks to see a slight chance for light rain in the evening. This precipitation expects to transition to light snow and increase in coverage to most of Yuma county along with portions of the NE counties overnight which might be the start of a possible winter event for the CWA that goes into the beginning of the long term forecast period. Daytime highs on Thursday expect to range between the middle 50s and the lower 60s followed by overnight lows in the upper teens to lower 30s. .LONG TERM...(Friday through Tuesday) Issued at 220 PM MST Tue Dec 7 2021 Friday...GEFS/GFS/ECMWF models remain in pretty good agreement bringing an upper level trough across the area during the day, moving east and away from the area during the night. At the surface, low pressure over southwest Kansas in the morning moves east into the Wichita area during the afternoon, reaching the Kansas City area by days end. Behind the surface low, a 1024mb surface moves into the area from the west. North winds gusting up to 35 mph or so are expected during the day with steadily decreasing winds during the night as the pressure gradient relaxes. The latest model runs have lowered the high temperatures compared to 12 hours ago with lower 30s to lower 40s currently expected. Blending the various 2m temperatures and MOS guidance numbers suggests that the current high temperature forecast may be a few degrees too high so further refinements may be needed. Low temperatures are expected to fall into the single digits to lower teens above zero in far eastern Colorado to the upper teens near Hill City. Regarding precipitation chances, the latest model trends have increased pops across all but the extreme east and southern parts of the forecast area (Hill City to Tribune south) as wraparound rain and snow looks more promising in the morning. Chances decrease some and include the entire forecast area in the afternoon with dry conditions expected during the night as the storm moves away from the area. At this time, snowfall amounts of a trace to an inch are expected from Cheyenne Wells to Norton northward, highest across Yuma county to McCook. The combination of snow and north winds gusting to 35 mph will likely produce some reduced visibilities at times with the highest chance along the KS/NE border during the day. Given that we`re still 72 to 84 hours out from this "event" and that the storm system itself has yet to develop further refinements to the forecast area likely. Saturday...broad upper level ridging redevelops over the area with high temperatures in the upper 30s to upper 40s and low temperatures in the middle teens to lower 20s. Breezy west to southwest winds are possible during the day, mainly across far eastern Colorado. If snowfall amounts from Fridays storm are higher, its likely that high temperatures for Saturday will need to be adjusted down due to snow cover. Sunday...high temperatures continue to warm with middle 50s to around 60 expected. Low temperatures are currently forecast to be in the upper teens to lower 20s. Monday...upper level heights slowly rise ahead of a developing upper level trough off the west coast. High temperatures are expected to be in the middle 50s to around 60 with low temperatures in the lower 20s to near 30. Tuesday...the forecast area is under southwest flow aloft ahead of the west coast upper trough which is forecast to move ashore. GFS/ECMWF/GEM 850mb temperatures are forecast to be in the 15C to 17C range which should easily support the current forecast of lower to upper 60s. Given typical mixing at 850mb these forecast highs could be several degrees on the cool side with highs in the 70s very possible. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 305 PM MST Tue Dec 7 2021 Both KGLD and KMCK expect to see VFR conditions throughout the 00Z TAF period. KGLD starts with southerly winds around 7 kts that become westerly around 12 kts at 02Z before slowing to around 7 kts again at 10Z. By 17Z, KGLD winds turn southwesterly and then return to southerly when they speed up to 13G21 kts at 18Z. The KMCK terminal sees south-southeasterly winds around 6 kts to begin the 00Z TAF period that turn southwesterly by 07Z. At 08Z, KMCK winds expect to become light and variable until 16Z when they become southerly again around 7 kts. By 20Z, winds at KMCK speed up to 13G20 kts for the remainder of the period. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...076 LONG TERM...99 AVIATION...076