Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/12/20

Area Forecast Discussion
National Weather Service Denver/Boulder CO
922 PM MDT Sun Oct 11 2020 .UPDATE... Issued at 840 PM MDT Sun Oct 11 2020 Winds have decreased for the night in the foothills and plains with boundary layer decoupling and will increase again with mixing tomorrow. Winds remain gusty in the mountians and will overnight. Northwest flow and lee troughing will mean another windy day, though winds are not expected to be quite as strong as today. The area will be dry and warm again, so fire danger remains widespread and critical. We have issued another Red Flag Warning for tomorrow afternoon. Some light snow fell on the fires in the mountains and suppressed smoke production today, and will continue to do so tomorrow. Transport winds also turned more westerly and these factors should give us a short break from the smoke that has impacted the area for the past few weeks. We updated the smoke grids by reducing the area impacted by smoke to only those close to the fires and along the Colorado- Wyoming border, east of the largest mountain fires. Otherwise, the forecast remains on track and no changes were made. && .SHORT TERM...(This evening through Monday) Issued at 316 PM MDT Sun Oct 11 2020 Lots going on right now as a vigorous trough moves across Colorado. Winds are peaking ahead of the shower band, with the strongest winds across Denver now. There was some smoke pooled right behind the front, but it`s been overtaken by a lot of blowing dust. Winds are starting to diminish north of Interstate 76 and the improvement will be dropping south across the area by early evening. Meanwhile, the mountains wound up getting pretty widespread precipitation west of the Front Range and a little ways down the east slopes. It`s mainly been light, but came fast enough for a little accumulation over the higher passes. This looks to have a couple hours left as well. The downslope will prevent anything around Denver, though there could be a few sprinkles out near the eastern border in the late afternoon. The low level winds will decrease some this evening. Still not sure about a possible northerly surge behind the trough that could produce a period of lighter north or northeast winds into Denver for a while in the evening. Otherwise, it will remain windy in the mountains and breezy on the plains through Monday. There is potential for some mountain wave amplification as warm advection aloft sets in overnight. It`s a pretty sheared environment, but it`s probably at least enough to keep speeds up over the ridges and higher east slopes. Warming aloft and low level southwest flow will bring temperatures back up to near today`s levels on Monday afternoon. Our moisture will be long gone, and humidities will be low enough for another Red Flag Warning for the foothills, South Park, and the plains. Jackson and Grand counties will also be close, the humidities will be a bit above Red Flag criteria but it will be another dry and windy day. The higher mountains will stay windy and the moisture that fell will be going away quickly. .LONG TERM...(Monday night through Sunday) Issued at 316 PM MDT Sun Oct 11 2020 Extended period of dry conditions expected over the next several days. Forecast period will start off with predominantly west- northwest flow aloft, with little in the way of moisture. It will be windy, with 700mb wind speeds near 30-40kt and the potential for another mountain wave Monday night. Cross-sections show cross- barrier flow of 30-50kt, so thinking is that gusty winds will continue across the more vulnerable areas of the high terrain and along the northern foothills. Temperatures Tuesday will be a bit warmer as mid-level temperatures warm a couple of degrees compared to Monday. Highs in the mid-upper 70s will be common across the plains. It will continue to be windy across much of the Front Range and northern foothills, with the strongest winds along the CO/WY border, where flow is strongest. Winds will continue through Tuesday night with another chance for more robust mountain wave development. Some deterministic guidance is quite bullish with the potential for very strong winds overnight. Winds overnight are progged to be nearly due west, with 40-60kt 700-500mb flow. By Wednesday, winds will likely spread across portions of the plains, especially along the WY/NE borders. Very strong WNW flow is expected to continue ahead of an approaching 100kt jet at 500mb. There could be just enough low-level moisture to produce a few showers, but continued fire danger will be the bigger concern given the duration and magnitude of wind gusts across the high terrain and northeast plains. A cold front will then quickly push south through the area late Wednesday into early Thursday, dropping temperatures substantially. Better confidence in cool highs Thurs across the plains, with highs in the low/mid 50s. Cold air should be short lived as the deep trough settles to our east over the Great Lakes Friday into this weekend. Temperatures will moderate back to near normal values for the plains (upper 60s) both Friday and Saturday, with less wind expected. More uncertainty in what the pattern does beyond Saturday, where there is little run to run consistency across the guidance. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 840 PM MDT Sun Oct 11 2020 Winds tonight will be late to follow normal diurnal patterns due to a northerly push behind today`s strong westerlies. Winds are expected to begin turning quickly after midnight to easterly around 7Z and then southerly by around 10Z. Winds have decreased significantly due to decoupling and normal speeds can be expected to prevail overnight. More gustiness in west-northwest winds can be expected tomorrow afternoon with mixing, however not nearly as strong as seen today. Skies have cleared and should remain clear overnight. The cloudiness upstream in the synoptic flow won`t reach the area until tomorrow. Light snows on the mountain fires limited smoke production today and will do so again tomorrow, which reduced the impact of smoke in the area significantly. Furthermore, more westerly transport winds have carried most of the remaining smoke well away from the terminals. The HRRRx near surface smoke product is available again and suggests that the area may remain fairly clear of smoke for the next two days. The RAP near surface and vertically integrated smoke products also support this, as well as the NASA GMAO biomass model. We have removed smoke from the TAFs and any visibility restrictions, and will continue to monitor the situation. && .FIRE WEATHER... Issued at 316 PM MDT Sun Oct 11 2020 Winds will decrease over the lower elevations this evening. It will be breezy all night but humidities will be higher. For the mountains there will be some decrease in the wind, but it will remain windy. The higher east slopes of the Front Range may continue to have very strong winds at times through Monday. Drier air moving in will result in lower humidities and Red Flag conditions over the foothills and lower elevations on Monday afternoon. Elevated fire danger will continue through at least Wednesday, with dry and windy conditions expected through mid-week. Across the higher terrain, gusty winds are expected even at night, with mountain wave potential both Monday and Tuesday nights. More widespread wind is expected Wednesday across the plains ahead of a strong 500mb speed max. Humidity values through Wednesday are forecast to be just higher than red flag conditions. However, still a lot of concern for the next several days given the longevity of the gusty winds, especially across portions of the Front Range and northern foothills. && .BOU WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon to 6 PM MDT Monday for COZ214>216- 238>251. && $$ UPDATE...Direnzo/Kriederman SHORT TERM...Gimmestad LONG TERM...Hiris AVIATION...Direnzo/Kriederman FIRE WEATHER...Gimmestad/Hiris
Area Forecast Discussion
National Weather Service Grand Forks ND
951 PM CDT Sun Oct 11 2020 .SHORT TERM...(Tonight through Monday night) Issued at 949 PM CDT Sun Oct 11 2020 Cold front located near Warroad to Bagley to just west of Wadena at 0230z. Area of showers and t-storms continue to move north- northeast along the boundary as it moves east. Severe threat ended around 0130z so watch has been dropped. Remaining showers and t-storms will exit the eastern fcst area 07z-09z period. General clearing expected overnight in eastern ND with winds diminishing as well into the 8 to 15 mph range. Lows looking ok at this point with upper 30s to low 40s from west to east. Looking at winds for Monday, they look sub advisory but a bit breezy west winds HRRR indicates in the 15-25 mph range in the aftn. Temp fcst of upper 50s to mid 60s. .LONG TERM...(Tuesday through Sunday) Issued at 300 PM CDT Sun Oct 11 2020 Opportunities for impactful weather will consist of a few midweek showers and maybe a period of light snow proximal to Lake of the Woods late week. Northwest flow will prevail on Tue, and with 850 ensemble winds progged at 30 kts or better, we could be looking at 20-30 mph near sfc winds along and west of the valley, given efficient mixing. During this time northern high plains low will be advancing to the east in developing zonal flow, increasing shower chances during the day on Wed. Guidance has been converging to a more POPful solution. Earlier in the day, some areas across the north could experience a few snowflakes mixed in with the liquid. Cyclonic flow remains through the end of the week, with Lake of the Woods on edge of area of scant moisture, but nevertheless it could combine with -8C or colder 850mb temps and the proper wind fetch to present a chance of a little lake enhanced snow shower activity. Snow plumes picking up on chance for minor accum. vcnty. KBDE Fri. After that the cooler air lingers over the entire region, with 850 mb temps remaining in the -4 to -8C range, limiting high temps to the 40s by then, with lows near or below freezing. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 707 PM CDT Sun Oct 11 2020 VFR thru the pd. Exception will be locally MVFR vsbys in t-storms BJI area thru 03z. Strong south winds diminishing in MN and turning west all areas overnight, but in the 8 to 15 kt range. West winds increasing to 15-25 kts Monday midday and aftn. Cloud deck in the 4000-8000 ft agl range then clearing spreading east && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ SHORT TERM...Riddle LONG TERM...WJB AVIATION...Riddle
Area Forecast Discussion
National Weather Service Memphis TN
644 PM CDT Sun Oct 11 2020 .DISCUSSION... Updated for aviation discussion && .PREV DISCUSSION... /issued 346 PM CDT Sun Oct 11 2020/ DISCUSSION... Clouds have hung tough across the Mid South today and there has been some small breaks over the northwestern portions of the forecast area. Expect the clouds associated with the remnants of Delta to continue to stick around through the evening. Low clouds and stratus is expected to be around overnight and some patchy fog is also possible. A front will approach the area tomorrow and essentially sweep out the humid air. A few light showers will be possible over the northeastern portions of the CWA as the front moves through. Nearly zonal west-northwest flow will prevail through Wednesday, with sunshine and southerly return flow warming Wednesday afternoon`s temps to around 80. A stronger front will move through the area on Thursday. This will bring a chance of rain but a shot of cooler air going into the weekend. && .AVIATION... VFR/MVFR deck across areas mainly along and east of the MS River this evening. Some clearing taking place across parts of NW TN. Big question tonight is whether the deck continue to break up which may allow fog/low clouds to develop with the potential for LIFR conds especially at KMKL and KTUP as depicted by the latest HRRR run. For now added some IFR vsbys due to fog at KMKL but kept the MVFR deck overnight at KTUP. KMEM should improve to VFR over the next few hours and remain VFR overnight along with KJBR. A front will move through on Monday with perhaps a few SHRAs and a period of MVFR cigs. Expect wind to become gusty from the W/NW by the afternoon. SJM && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Monday) Issued at 324 PM CDT Sun Oct 11 2020 Early this afternoon an upper level trough was located across the central Rockies. At the surface a lee surface trough was located across the central and southern high plains. The pressure gradient east of the lee surface trough across central and eastern KS has caused southerly winds to increased to 15 to 20 MPH with gusts of 25 to 30 MPH through the late morning hours and will continue through the afternoon hours. Tonight, as the upper trough across the central Rockies, lifts northeast into the central Plains a line of thunderstorms will develop along the front across MN and north central IA due to surface convergence ahead of the surface front and and DCVA ahead of the H5 trough. The line of storms will backbuild southwest towards north central KS along the NE border during the early evening hours. There still remains some uncertainty if storms will develop along the front across north central KS this evening. The HRRR and ARW-NMM west CAMs keep most of the convection north of the CWA. Meanwhile, the 3KM NAM and ARW-NMM east CAMS do show thunderstorms backbuilding southward across north central KS this evening and spreading rapidly east across the CWA during the late evening and into the very early morning hours of Monday. At this time I used a blend of the CAMs, which matched the RAP model and have the highest pops north of I-70. If storms manage to develop across the CWA, ahead of the front, MUCAPEs will be 1000-1500 J/KG with effective shear of 30 to 40 KTS. Thus, the combination of instability and vertical windshear may produced some organized updrafts within the line of storms that may produce large hail, especially any updrafts that exhibit mid-level rotation. Damaging wind gusts may be the primary hazard if the line of thunderstorms back build into the western counties of the CWA through the evening hours and shifts east. Behind the front there will be rapid pressure rises and strong low- level CAA as the H5 trough axis shifts east-northeast cross the central Plains. Several CAMs forecast north-northwesterly 925MB winds of 50 to 60 KTS. I expect a window of 2 to 3 hours after FROPA for wind gusts to be 40 to 45 KTS (45 to 55 MPH) just behind the front. I think the PBL may decouple just enough to prevent the momentum transfer of 50 KTS winds to the surface but this will have to be watched by the next shift, just in case low-level lapse rates remain steep enough after sunset. Therefore, I have expanded the wind advisory to cover the entire CWA Tonight. The front will exit the CWA by 10Z and winds will subside from west to east across the CWA during the early morning hours of Monday. Overnight lows will be in the mid 40s across north central KS to the lower 50s across the northeast counties. Monday, northwest winds will be breezy during the morning hours but will slowly back more to the west and subside under 10 KTS by late afternoon. Highs on Monday will be cooler but still pleasant with highs in the lower to mid 70s. .LONG TERM...(Monday night through Sunday) Issued at 324 PM CDT Sun Oct 11 2020 Expectwest-northwest mid and upper level flow across the Plains through through the extended forecast period with dry conditions. Afternoon high temperatures will warm into the mid to upper 70s on Tuesday with lower to mid 80s by Wednesday, ahead of the surface front. An upper level trough will dig southeast across the Plains Wednesday into Wednesday night and this will cause a cold front to push southeast across the CWA late Wednesday afternoon into Wednesday evening. Thursday will be much colder with highs only reaching the upper 50s to lower 60s with only a slow moderating trend into next weekend. There may be a chance for frost Friday morning with lows in the lower to mid 30s but we are approaching the average first freeze date. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 658 PM CDT Sun Oct 11 2020 Winds continue to be the main aviation concern for this period. Gusty winds will weaken allowing for LLWS to develop this evening ahead of a surface cold front. SSE winds shift to the NNW with strong wind gusts of 40-45 kts behind the front. Showers and storms are possible as the front passes, but the better chance for precip looks to be north of terminals. Winds and wind gusts weaken through the day on Monday. && .TOP WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 10 PM this evening to 3 AM CDT Monday for KSZ010>012-022>024-035>038. Wind Advisory from midnight tonight to 5 AM CDT Monday for KSZ026-039-040-054>056-058-059. Wind Advisory until midnight CDT tonight for KSZ008-009-020-021- 034. && $$ SHORT TERM...Gargan LONG TERM...Gargan AVIATION...Flanagan