Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/06/22

Area Forecast Discussion
National Weather Service North Platte NE
643 PM CDT Wed Oct 5 2022 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... Issued at 358 PM CDT Wed Oct 5 2022 H5 analysis this morning had a closed low off the coast of the Delmarva Peninsula. A ridge was located west of this feature and extended northeast from the lower Ohio Valley into the eastern Great Lakes. West of this feature, closed low pressure was located over northwestern Iowa. A trough extended southwest of this feature into southeastern Nebraska. A secondary shortwave trough was located over southwestern New Mexico. Further west, ridging extended from central California, north into the Idaho Panhandle. Skies were partly to mostly cloudy this afternoon across the area. With northwesterly winds of 10 to 20 MPH, 3 PM CT temperatures ranged from 69 at Gordon, to 76 at North Platte. && .SHORT TERM...(This evening through Thursday night) Issued at 358 PM CDT Wed Oct 5 2022 A strong cold front will approach northern Nebraska tonight, then track across western and north central Nebraska on Thursday. For tonight, expect mainly clear skies with winds becoming more northerly across far northern Nebraska toward morning. The latest NAM12 and GFS solns have the front entering far northern Nebraska by 12z Thursday morning. Overnight lows will bottom out in the lower to middle 40s. On Thursday, a strong cold front will pass through most of the area by 21z Thursday. Winds behind the front will be northerly with a northeasterly shift in winds late in the day. Temperatures will vary widely across the area on Thursday. With the morning passage of the front, temperatures will struggle to rise out of the middle 50s north of highway 2. Further south, the afternoon timing of the fropa, will allow highs to reach near 70 south of I-80. Thursday night into Friday will prove to be the most impactful and difficult portion of the forecast. Beginning Friday night, as the surface front backs west into the Panhandle, then front range of Wyoming and nern Colorado, favorable mid and upper level lift will approach, then track across the forecast area from the northwest. The latest NAM12 and GFS solns, along with the 12z HRRR (to 12z Friday), develop a distinct northwest to southeast oriented band of precipitation across the forecast area. ATTM, the NAM12, 12z HRRR, NAMNEST, and GEFS ensembles have this band of precipitation from Sheridan county, south southeastward into Lincoln, SW Custer and Frontier counties. Impacts to the forecast which hinge on the location of this band are two fold. First: Cross sections taken perpendicular to the strongest mid level frontogenesis, indicate strong short duration vertical lift (possibly convective) within the band. Temperatures will fall off to the middle to upper 30s Friday morning in central and western Nebraska. Normally not a huge concern for snow, however, if the strong vertical lift materializes, we could see some good dynamic cooling in the most intense areas of precipitation. This may lead to some wet snow from 3 AM-9 AM MT Friday morning. As for impacts from this snow, winds will be light so no blowing snow is expected. However, there may be some threat for localized, brief, moderate to possibly heavy bursts of snow. As better forecast confidence in the location of the band and if the models continue to trend toward stronger mid level lift, we may need to trend our hazards messaging more toward the threat for snow Friday morning. Second: The location of the band will influence cloud cover and the threat for frost/freezing temperatures Thursday night. ATTM, feel the best confidence in this occurring is over the far northeast. That being said, went ahead and trended temps downward utilizing a blend of NBM, with MET and MAV guidance (which was 27 and 29 respectively for KONL). The NBM kept temps slightly elevated vs. the statistical guidance. This seemed like a good compromise if the GFS were to verify and clouds were to be more prevalent in the NERN CWA. Precipitation will shift southeast into southwestern Nebraska late Friday morning, before exiting the area Friday afternoon. Temperatures should warm by late morning into the upper 30s/lower 40s, mitigating the threat for snow. Temperatures will remain very cool Friday as cloud cover will be prevalent across the area. Highs will only reach into the upper 40s to around 50. .LONG TERM...(Friday through Wednesday) Issued at 358 PM CDT Wed Oct 5 2022 Skies will gradually clear across the north and eastern forecast area and feel fairly confident in widespread frost and freezing temps. Further west and southwest, clouds may linger into Saturday morning, limiting frost potential along and south of Interstate 80. Cloud potential will need to be monitored closely as this will factor into frost development or not in SW Nebraska. Beyond Friday night, we should see dry northwesterly flow through Monday. An upper level low and trough will deepen across the intermountain west toward the middle of next week. This will lead to southwesterly flow aloft and some moisture return to the area. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 642 PM CDT Wed Oct 5 2022 A strong cold front will move through western and north central Nebraska tomorrow morning, causing winds to shift to the north and northeast between 10 and 15 knots. MVFR ceilings will develop in northern Nebraska including KVTN between mid-morning and the early afternoon as this happens. Otherwise, VFR conditions are expected. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...Meltzer
Area Forecast Discussion
National Weather Service Marquette MI
810 PM EDT Wed Oct 5 2022 .SHORT TERM...(This evening through early tonight) Issued at 133 PM EDT WED OCT 5 2022 GOES Water Vapor imagery and RAP analysis show a mid-level low slowly progressing through the Dakotas and into Iowa. A surface boundary dropping into western Lake Superior is supporting cloud cover over western Upper Michigan and some light radar reflectivities are starting to pop up over the far west and west of the Keweenaw. Some additional development will be possible along this boundary this afternoon and evening as it presses eastward. Further upstream, a shortwave and surface front are moving into northwestern Minnesota will be the focus for the next round of showers, mainly after midnight tonight and into Thursday. .LONG TERM...(Thursday night through Wednesday) Issued at 314 PM EDT WED OCT 5 2022 Below normal temperatures prevail throughout the extended forecast period with near normal precipitation along the lakeshores to below normal precip away from Lake Superior. A seasonably strong cold front tracks southeast across our area shortly after midnight with a secondary surface trough following a few hours later. Winds increase behind the initial front, but the secondary feature brings cooler air, deeper mixing, and stronger winds during the daylight hours on Thursday. This should result in a non-diurnal temperature curve with falling temperatures, especially during the afternoon hours. In terms of precip chances, there could be a few pre-frontal shower but showers are much more likely along the initial cold front. There is some weak pre-frontal instability (~250 J/kg), but think it`s insufficient for thunderstorms. Behind the front, CAA saturates low levels resulting in lake effect clouds and primarily orographic showers until colder air arrives behind the secondary trough. Mid-levels are dry while lake effect precip is ongoing indicating a pure lake effect environment. In general, the lake effect environment is characterized by inversions around 3-4 kft with a briefly higher values up to 5 kft possible. Thermal profiles suggest pure rain until Thursday night when our higher elevation locations should mix with if not changeover to graupel/snow. Marginal temperatures and light to moderate precip rates suggest little if any accumulation that would be confined to grassy/elevated surfaces. Lake effect showers gradually end from west to east on Friday as the surface ridge axis moves overhead. Friday night`s temperature forecast is tricky, because there`s potential for much colder temperatures if clear skies/calm winds materialize. However, with the surface ridge positioned well to our southwest over the Central Plains, mixing may limit nocturnal cooling. The pressure gradient strengthens on Saturday between the ridge to our SW and a low near James Bay, which may result in some low-end westerly gales. A weak cold front follows later on Saturday with surface ridging providing more tranquil weather through early next week. An amplified pattern develops by the middle of next week as deep troughing moves into the Pacific NW sending a much warmer air mass our way. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 810 PM EDT WED OCT 5 2022 VFR conditions will prevail into tonight with abrupt deterioration in the Thu 06-09Z time frame as a cold front tracks through the region. TAFs will quickly deteriorate to IFR levels, especially at KIWD and KCMX with onset of rain. Would not entirely rule out LIFR conditions, but confidence is not high enough at this time to mention CIGS that low. Northerly winds will also be an impact early tomorrow morning at KCMX and KIWD in the wake of the front with sustained speeds in the 12 to 18 kt range and gusting as high as 30 kts at KCMX. KIWD will gust up to 26 to 28 kts. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 326 PM EDT WED OCT 5 2022 Light winds of 20 knots or less continue across Lake Superior until late tonight, when a strong cold front drops down from northern Ontario. Expect winds to quickly increase behind the cold front late Wednesday night into Thursday, with northerly gales of 35 to 40 knots seen across the lake by late Thursday morning. Expect north winds to decrease Thursday night into the 20 to 25 knot range late as building high pressure weakens the pressure gradient across the area. However, northerly gales to 35 knots could persist into early Thursday evening over the east half. Winds briefly diminish to 20 knots or less on Friday as they back west-northwest in the afternoon. West winds then increase again to 20 to 30 knots Friday night into Saturday as another low pressure system moves across northern Ontario. Would not be surprised to see a few gale gusts to 35 knots off the tip of the Keweenaw Peninsula late Friday night into early Saturday. Light winds of 20 knots or less eventually return Saturday night into Monday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning from 8 AM to 5 PM EDT Thursday for LSZ162. Gale Warning from 8 AM to 7 PM EDT Thursday for LSZ240>244-263- 264. Gale Warning from 8 AM to 10 PM EDT Thursday for LSZ245-248>251- 265>267. Lake Michigan... None. && $$ SHORT TERM...JTP LONG TERM...EK AVIATION...TDUD MARINE...JTP
Area Forecast Discussion
National Weather Service Missoula MT
226 PM MDT Wed Oct 5 2022 .DISCUSSION...Above normal temperatures will continue through the rest of the week. The ridge of high pressure will slowly retrograde westward, allowing for easterly winds to develop across western Montana overnight and Thursday. This will also allow for cooler temperatures compared to the past couple days, but will remain slightly above normal for this time of the year. The HRRR smoke model is projecting areas of haze, particularly across west- central Montana through Friday of this week. Forecast ensemble members continue showing an increasing likelihood for a wet and colder weather pattern arriving Tuesday and Wednesday next week, as a closed mid-level low pressure traverses the intermountain west. Currently there is around a 70% chance for this pattern to occur. Where the uncertainty remains, are the details in how much rain occurs, and how low the snowlevels ultimately get. As it stands now, there is about a 30% chance that the high valleys along the Continental Divide will receive up to an inch of snow by Wednesday morning. There could even be a few snow flakes falling in the valleys across the Flathead, south into Missoula. As the system exits the region Wednesday, a colder Canadian air- mass will settle in over the region. This will allow for the potential of the first widespread frost/freeze in the valleys of western Montana and north-central Idaho. Currently, there is a 50% chance for the valleys of western Montana to wake up to lows in the mid 20s Wednesday, Thursday and Friday mornings. There is also a 32% chance for areas in the vicinity of Grangeville and Pierce to lower to around 32F degrees. Make plans to protect those sensitive plants and vegetation. Long range forecast models indicate another ridge of high pressure arriving by next weekend, allowing for normal temperatures and drier conditions to return. && .AVIATION...Patchy fog is again expected to develop by morning across the Northern Rockies, with VCFG likely for KGPI and KMSO through 06/1500Z. An easterly gradient will develop overnight, producing a light easterly breeze. This will keep most of the fog at bay, and will likely be confined to local bodies of water. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$