Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/19/21

Area Forecast Discussion
National Weather Service La Crosse WI
603 PM CST Sat Dec 18 2021 .SHORT TERM...(This evening through Sunday) Issued at 235 PM CST Sat Dec 18 2021 -Quiet weather rounds out the weekend with seasonal temperatures. It`s been a wild last week of weather and a well deserved break continues for the rest of the weekend. A shallow upper level trough brought light snow to the region this morning, but has since shifted east of the forecast area. Low stratus/stratocumulus persists well into the overnight hours within the northwesterly flow in place over the Upper Mississippi River Valley. Surface ridging over the eastern Dakotas meanders eastward for tonight and departs by sunrise. Southerly flow increases during the day ahead of the next frontal system ejecting across the Northern High Plains. The biggest question in the forecast revolves around low-level cloud cover, especially on the backside of the ridge axis. RAP forecast profiles are quite robust on keeping the low clouds around while over solutions are not as bullish. The best chance of clearer skies will be over the southern forecast area during the day on Sunday. Modest WAA during the day should nudge highs on Sunday back into the low to mid 30s area-wide. .LONG TERM...(Sunday night through Saturday) Issued at 235 PM CST Sat Dec 18 2021 -Weak weather systems move through during the week with the impactful snow threat on the low side. -Keep an eye on the forecast for around the Christmas holiday. A progressive upper level pattern ushers multiple weak disturbances over the region, the first of which will be on Sunday night into Monday. Forecast soundings and EPS progs are quite dry with its passage, with the best chance of any light flurries being over northern Wisconsin. High pressure builds in for late Monday into Monday night, with the next undulation rippling through on Tuesday. The track of this system follows a similar course to its predecessor, mainly north of the forecast area with the best chance of snow residing over northern Wisconsin and the Minnesota Arrowhead. The next system in the caravan comes through Wednesday night, but again will suffer from a lack of moisture and will be rather transient in nature. Confidence in the forecast going into the Christmas holiday degrades, but a deepening upper tropospheric trough across the Pacific NW could eject several shortwaves over the region during the holiday weekend that may have a better chance of producing impactful precipitation. The temperature forecast for the first half of the week varies little with highs in the 30s, but there are hints that warmer air returns for the end of the week. Most of the ensemble guidance is pushing into the 40s for that timeframe. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 555 PM CST Sat Dec 18 2021 Variable MVFR/VFR ceilings tonight with weak low level flow and patches of cloud-free areas. Light northwest winds become south Sunday and increase 12 to 18kts with gusts 20 to 30kts. Some flurries possible, however confidence in timing too low to include. Ceilings improve to VFR 16-20Z with high clouds in the area. Potential for low level wind shear increases after 22Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Skow LONG TERM...Skow AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Lincoln IL
734 PM CST Sat Dec 18 2021 .SYNOPSIS... Issued at 145 PM CST Sat Dec 18 2021 Dry weather is expected the rest of the weekend and through most of next week, with chilly temperatures through tomorrow. However, warmer conditions are expected through the new week. && .UPDATE... Issued at 733 PM CST Sat Dec 18 2021 Main forecast issue tonight will be with the clouds. Stratocumulus is mostly limited to areas near/east of I-55 early this evening, with some renewed development just southwest of Peoria. Additional clouds around 2,000 feet are oozing south from northern Illinois. While some holes are developing upstream over parts of Wisconsin and Iowa, the latest HRRR model shows these clouds spreading over much of the CWA west of I-57 after midnight. This is supported on RAP soundings by a pinch of moisture around 900 mb increasing after midnight, though the new NAM is showing a slower arrival of said moisture. Did some beefing up of the sky cover in the grids, though this did not have an appreciable effect on the worded forecast. && .SHORT TERM...(This evening through Sunday) ISSUED AT 145 PM CST Sat Dec 18 2021 High pressure will drop into the area by tomorrow morning with dry conditions. Chilly temperatures are expected through Sunday with overnight lows in the middle to upper 20s followed by Sunday highs only in the middle to upper 30s. && .LONG TERM...(Sunday night through Saturday) ISSUED AT 145 PM CST Sat Dec 18 2021 Dry weather is expected through most of the period despite a cold front moving through the state middle of the week. The next chance of rain will be Friday afternoon through Friday night, but there is some considerable spread with model solutions at this point. Therefore, an ensemble forecast looks good for now, with pops in the slight chance category over most of the CWA and chance pops in far eastern IL for Friday evening. Hopefully a better consensus will be seen with later model runs. Most of the precip that does occur during that period will be rain, but a mix of rain and snow might occur in far northern parts of the CWA Friday night. The main focus in the extended period is temperatures. All extended model ensembles agree that warmer than normal temps will occur Thur through Sat. A large area of unseasonably warm air is expected to build across the middle of the US from middle of the week into the Christmas weekend and this will include central IL. After normal temps for Wed, behind that dry cold front, temps are expected to reach into the 50s by Fri and Sat, which is around 15 degrees above normal for this time of year. These warm conditions in December do occur in central Illinois at times, but will be nowhere near records, as those are in the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 522 PM CST Sat Dec 18 2021 While much of central Illinois is still seeing ceilings below 3,000 feet early this evening, a clear area was located in western Illinois and adjacent areas across the Mississippi River. Some concern as to how much of this is going to remain clear, as stratocumulus oozes south from Iowa/northern Illinois. HRRR ceiling plot suggests potential for southward expansion, especially after 06Z. Will need to monitor this closely, but for now, am thinking all terminals should be VFR by about 03Z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SYNOPSIS...Auten SHORT TERM...Auten LONG TERM...Auten AVIATION...Geelhart
Area Forecast Discussion
National Weather Service North Platte NE
548 PM CST Sat Dec 18 2021 .SHORT TERM...(This evening through Sunday night) Issued at 337 PM CST Sat Dec 18 2021 The models are in very good agreement warming h850mb temperatures to around 10C Sunday. This should support highs in the mid 50s or warmer and the temperature forecast leans on the warmer RAP model for highs. This is near the 50th percentile of the NBM but a few degrees cooler than the very warm guidance blend. Given that high clouds will remain mostly north of the region, the temperature forecast Sunday could be too cool. The guidance blend plus bias correction is in place for lows in teens and single digits tonight, and teens and 20s Sunday night. A southerly low level jet develops tonight in tandem with low level warm air advection. A back door cold front will begin moving through wrn and ncntl Nebraska Sunday night. Thus, neither tonight nor Sunday night appear to be strong radiational cooling events, especially given the SREF indicates stratus will form along the cold front Sunday night. .LONG TERM...(Monday through Saturday) Issued at 337 PM CST Sat Dec 18 2021 There is little change in the extended forecast philosophy today. A Pacific cold front will move through wrn and ncntl Nebraska Tuesday followed by a protracted period of warm air advection Wednesday through Saturday. The ECM and GEM suggest the potential for a back door cold front Friday night but it would appear the front will hold up and become stationary across the Missouri river valley, just north and east of wrn and ncntl Nebraska. WPC, like the GFS, supports this forecast. The models are in very good agreement developing a long wave trof off the West Coast next week and place a 984-994 mb sfc low off the coast of Washington state by Friday. The associated long wave trof off the West Coast should support a surge of warm desert air across the Rockies and into Nebraska Tuesday and beyond. Highs in the 40s and 50s are in place Tuesday through Saturday- cool air and stratus hold down highs Monday to the 20 and 30s. The temperature forecast Tuesday and beyond is middle-of-the-road for one reason-bouts of high level cloudiness at times will affect the very short daytime heating cycle. If the high clouds can hold off presenting a clear day, highs in the upper 50s and 60s could result according to the 90 percentile of the NBM. Later forecasts may mark up highs several degrees as the predictability of high cloudiness will improve. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 546 PM CST Sat Dec 18 2021 VFR conditions should prevail over the next 24 hours. Winds will gradually shift from the southeast this evening to the south overnight, then to the southwest tomorrow morning. Winds may become gusty across the area tomorrow afternoon, peaking between 20 and 25 knots. Skies should be mostly clear aside from some high clouds. && .FIRE WEATHER... Issued at 337 PM CST Sat Dec 18 2021 Little change was noted in the wind and humidity forecast Sunday. Fire weather conditions are expected to be elevated across western Nebraska Sunday afternoon. The predicted single digits to near 10F dew points and temperatures in the 50s result in humidity in the 15 to 20 percent range. The lowest values are expected across swrn Nebraska and the srn Panhandle and winds are in the 10 to 20 mph range in this area. North, generally along and north of highway 2, humidity increases to around 20 percent and winds increase to 20 to 25 mph. Much of this area received significant rain and snow Wednesday, and in some cases, snow is still on the ground melting. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Meltzer FIRE WEATHER...CDC