Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/08/21

Area Forecast Discussion
National Weather Service Boise ID
845 PM MDT Tue Sep 7 2021 .DISCUSSION...Tons of smoke was released from fires to our west and southwest this afternoon, and a good portion of that will move into our area over the next day or two. There is still some hope for improvement Friday, but there are so many fires out there now that virtually any direction our upper level flow comes from will bring at least some smoke into the area. Latest guidance shows a slightly increased chance for showers/thunderstorms Thu aft/eve, and this will be examined by the overnight shift in the next full forecast package, once the remaining 00Z guidance arrives. No changes are planned at this time. && .AVIATION...Widespread smoke layers with periods of MVFR-IFR visibility and terrain obscuration. Surface winds: 10 kts or less overnight, then SW 10-20 kts across SE Oregon and the mountains of SW Idaho, and SE 10-20 kts across the Snake River Plain after 08/15Z, becoming W to NW area-wide after 08/21Z. Winds aloft at 10k ft MSL: NW 10-20 kts becoming SW 10-20 kts early Wednesday morning. && .PREV DISCUSSION... SHORT TERM...Tonight through Thursday night...Air quality advisories due to wildfire smoke have been posted for all of our CWA by the Idaho DEQ and Oregon DEQ. In eastern Oregon the advisory runs through at least Thursday afternoon. In Idaho the advisories for southwest Idaho and south-central Idaho will be updated Wednesday before 1 PM MDT. Latest HRRR smoke model continues smoke throughout our CWA through at least Thursday morning. Above-normal high temperatures will also continue through Thursday as the upper ridge over the Great Basin shifts very slowly east. Temperatures would be several degrees higher if not for the smoke. Late Thursday night a Pacific upper trough will reach the northwest coast. The trough will begin a chance of showers and thunderstorms in Harney County/OR as early as Thursday afternoon, and eastward into the Idaho Mountains late Thursday night. Clouds will inhibit cooling Thursday night before a cold front and showers arrive Friday morning. West winds will increase Wednesday afternoon in eastern Oregon and in the higher terrain of western Idaho. Humidity will stay low and the winds and dryness will increase fire danger. LONG TERM...Friday through Tuesday...Model guidance remains in close agreement with an embedded shortwave passage on Friday. Good upper level support and sufficient moisture should allow for thunderstorms development. Precipitable waters approaching 90-95 percentile would suggest these storms could produce measurable rainfall across much of the area along with gusty winds. Temperatures will drop about 10 degrees behind the system. Showers may linger in the mountains on Saturday as the flow turns more northwesterly, rather than southwesterly, which should help to push some of the smoke and haze out of the area, and allow temperatures through the weekend to get down to near normal. The ensembles still have quite a bit of variation in solutions beyond Sunday, but appears to be a bit more supportive of weak troughiness and cooler temperatures for early next week, rather than a return to a strong ridge. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning from noon to 9 PM MDT Wednesday IDZ402-403. OR...None. && $$ DISCUSSION...SP AVIATION.....SP PREV SHORT TERM...LC PREV LONG TERM....JDS
National Weather Service Hastings NE
655 PM CDT Tue Sep 7 2021 .DISCUSSION...(This evening through Tuesday) Issued at 242 PM CDT Tue Sep 7 2021 Quiet weather continues this week. The cold front has pushed well south of the area, and the entire area is seeing gusty north winds in its wake. Skies remain clear aside from some haze from the high level smoke just behind the front. Fortunately, satellite analysis and the HRRR smoke model indicate that clearer air will move in from the north by this evening. Tonight, decreasing winds and relatively dry air will promote efficient radiative cooling. In fact, some guidance takes the typically cold portions of the area (Valley/Dawson counties) into the upper 40s. This would make tonight the coolest night in quite some time. Ord Airport has actually not been in the 40s since early June! There is high confidence that the rest of the workweek will remain dry and warm. In fact, none of the 51 EPS ensemble members produce any QPF for the area through Friday. Temperatures will also remain above-normal as the western ridge slowly translates eastward. Tomorrow and Thursday will be in the 80s for most, with temperatures likely reaching the 90s in many spots by Friday as the upper ridge centers over the area. A shortwave will flatten out the ridge on Saturday and push a cold front through the area. Exact model solutions vary, but it appears this will bring at least a low chance for a few showers and thunderstorms to portions of Nebraska Saturday night. This will also knock temperatures back into the 70s and 80s for Sunday. A second trough then pushes through the central/northern Plains during the Sunday-Monday timeframe, bringing slightly better chances for showers/storms for the beginning of next week. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 643 PM CDT Tue Sep 7 2021 VFR conditions will continue throughout the TAF valid period with clear to mostly clear skies. The wind will be fairly light tonight into Wednesday. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ DISCUSSION...Mangels AVIATION...Wesely
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
945 PM CDT Tue Sep 7 2021 .UPDATE... 02Z surface analysis showed a cold front extending from west central OK, to extreme southeast KS and southern MO. Storms developed rapidly along the front late this afternoon, aided by dewpoints around 70F, and afternoon highs in the lower 90s. This front remains on track for passage through the Midsouth on Wednesday. Moisture pooling near the front (expected surface dewpoints near 65F and 925mb dewpoints near 18C) will result in a narrow strip of higher precipitable water values, near 1.8 inches in the vicinity of the front. Modest mixed layer instability, at or below 500 J/KG CAPE is progged by the HRRR north of I-40 during the morning, and a little north of 1000 J/KG over north MS Wednesday afternoon. NBM hourly precip-probability index appeared underdone, but higher than earlier today. For those areas that do see rain Wednesday, it will be sufficiently brief that measuring more than a trace may be a challenge. Forecast remains on track at this time, following minor adjustments. PWB && .PREV DISCUSSION... /issued 621 PM CDT Tue Sep 7 2021/ UPDATE... Updated to include 00Z Aviation Discussion. PREV DISCUSSION... /issued 251 PM CDT Tue Sep 7 2021/ DISCUSSION... Northwest flow aloft continues across the Mid-South downstream of the anomalous ridge over the Intermountain West. This ridge is quite strong with 500 mb geopotential heights among max climatological values across NV/UT. Meanwhile, a fairly strong trough is digging over the Great Lakes leading to a +PNA synoptic pattern. We tend to see less in the way of precipitation during this pattern with little in the way to temperature variability. Precipitable water is near 0.6" across the Mid-South which is below the 10% percentile for early September. This is allowing dewpoints to fall into the mid/upper 50s, and will result in a terrific evening across the region. In the near-term, the trough digging across the Great lakes will send a weak cold front through the Mid-South tomorrow. Low-level moisture return ahead of this system will be scant, but we do anticipate an uptick in column moisture along/ahead of the cold front with a band of PWATs near 1.75". Instability appears pretty mediocre with MUCAPE in the 500 J/kg range for most of the area. There is an increase in instability across north MS during the afternoon and the GFS/NAM both try to erode the cap by 21z as the boundary approaches Tupelo. Some of the CAMs are hinting the potential for a thin, broken line of weak convection across portions of west TN and northeast MS. Will carry 20 PoPs to account for this. The western ridge shifts a bit eastward over the Southern Rockies by the end of the week, finally breaking down late in the weekend and allowing the westerlies to sink farther south across the CONUS. However, the dry, post-frontal air mass will drop PWATs back below 0.75" Thursday, with little increase through Saturday. Dry and warm conditions will prevail during this time with afternoon temperatures in the 80s (with some 90s over the weekend) and lows in the 50s and 60s. The ridge holds a tenuous grip on the Mid-South weather through early next week, but the latest guidance indicates a trough swinging through the area around midweek. This may be our next notable chance for showers and thunderstorms across the region. MJ && .AVIATION... 00Z TAFs Patchy fog may produce temporary MVFR conditions at TUP between 08/08-12Z. Otherwise, VFR conditions expected to prevail at TAF sites through the period. A cold front will move through the area on Wednesday with light winds increasing to NW winds between 7-11 kts with a few higher gusts. VCTS also possible late Wednesday morning at MKL and Wednesday afternoon at TUP. CJC && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Pueblo CO
248 PM MDT Tue Sep 7 2021 .SHORT TERM...(This evening through Wednesday) Issued at 247 PM MDT Tue Sep 7 2021 Currently... Hazy and very warm conditions were noted over the region at 2 pm. Temperatures were primarily in the lower 90s across most of the plains with 80s in the valleys. Skies were clear (of clouds) and hazy/smoky skies were noted over most locations. Rest of Today and into Tonight... Main concern will be haze/smoke. Several runs of the HRRR smoke forecast indicate the worst of the smoke along the I-25 corridor and the mountains will will occur this afternoon and into the early evening, with the smoke decreasing with time thereafter. Although the front has gone by, it remains very dry and no precip is anticipated through tonight. breezy winds this afternoon over parts of the region will decrease, except in the San Luis valley where easterlies will push over the southern mtns, causing breezy conditions in the valley this evening. Lows tonight will be in the 50s plains and 40s valleys. Tomorrow... Smoke will increase once again although it is not anticipated to be as dense as this afternoon. Temperatures tomorrow are expected to nearly identical to todays max temps. It will also remain dry. Likewise, expect highs on the plains to be in the upper 80s across the divides (Palmer and Raton), with generally mid 90s across the lower Ark Rvr valley. Valleys will be in the 80. /Hodanish .LONG TERM...(Wednesday night through Tuesday) Issued at 247 PM MDT Tue Sep 7 2021 Thursday - Friday... The start of the long term period is expected to bring a torrid pattern to the area, especially over the eastern plains. A large ridge/high pressure will continue to crawl its way eastward Thursday through Friday. This large high pressure will advect dry low to mid level air into the region throughout these couple of days. Given the synoptically sinking air directly over the area and the dry air being pushed into the region, precipitation chances will be negligible. The main impacts from this pattern will be the increase in temperatures, especially Friday, when the ridge center/axis will be sitting directly over Colorado. High temperatures will easily be near or above record values Thursday and Friday, with the best potential for this on Friday. Saturday - Tuesday... Heading further into the long term period, the GEFS and EPS ensemble models are good agreement about the evolution of the pattern over the next several days. Saturday will bring the first reprieve from the hot temperatures. A short wave trough will pass just to the north of Colorado. This trough will transition winds aloft to become more westerly and bring better forcing aloft. The trough will also bring a modest increase to low to mid level moisture over the region. With the increased synoptic forcing, orographic lifting, and moisture present, precipitation chances will increase over the mountains. Out over the plains, a weak cold front will drop southward as the short wave treks eastward. This will drop temperatures down away from record values, but still above average. Sunday another trough will begin materializing to the north. The wave will have limited impacts on Sunday though, with a slight decrease in moisture behind Saturday`s short wave and stronger forcing staying further to the north. Isolated precipitation will be possible over the central part of the Continental Divide as winds aloft are still westerly and focused into the mountains. Diving into Monday, the aforementioned trough from Sunday will begin digging southward over the central plains. A stronger cold front is expected to drop southward in response to this, and will bring cooler temperatures again. Moisture will also slightly increase behind the cold front, and given the easterly winds behind it, upsloping along the eastern mountains may produce precipitation during the afternoon. During the last day of the long term period, Tuesday, a weak upper level ridge will push eastward over the region, before beginning to fatten out. Drier air will be advected in with this ridge and precipitation chances will drop as compared to the past few previous days. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 247 PM MDT Tue Sep 7 2021 Some smoke and haze will be an issue at the taf sites this period. The densest smoke/haze is expected to be this afternoon with it decreasing somewhat this evening into tonight, with the smoke increasing somewhat once again tomorrow. This may cause visibility to down to 5-6sm at times at the taf sites. Otherwise no other sensible weather is anticipated. At KALS, breezy east winds are anticipated this evening. Otherwise expect diurnal flow the next 24 hours. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HODANISH LONG TERM...SIMCOE AVIATION...HODANISH
Area Forecast Discussion
National Weather Service Riverton WY
550 PM MDT Tue Sep 7 2021 .SHORT TERM...(This Afternoon through Wednesday Night) Issued at 242 PM MDT Tue Sep 7 2021 Northwest flow aloft over the region this afternoon as an upper- level ridge sets up shop in the Great Basin. Cirrus clouds rotating around the periphery of the ridge have been drifting across the forecast area. Otherwise, wildfire smoke has caused reductions to visibility at times as it settles into the valleys and basins without much wind to mix the lower atmosphere. This trend continues overnight as northwest flow persists. Another night of good radiational cooling, so minor adjustments made for low temperatures and relative humidity in the western valleys and basins. Ridge axis reaches the western Wyoming border late Wednesday. Cirrus cloud cover dissipates through the day leaving another mostly clear sky. Daytime highs inch upward Wednesday as 700mb temperatures climb toward +15C. Readings 5F to 10F above normal will be widespread across the entire forecast area. There will be little wind Wednesday with the ridge in place. Smoke will continue to pose a problem with HRRR vertically integrated smoke forecasts showing smoke from central Idaho wildfires filtering into the state Wednesday and Wednesday night. Again made adjustments to low temperatures and overnight relative humidity in the western valleys and basins. .LONG TERM...(Thursday through Tuesday) Issued at 358 PM MDT Tue Sep 7 2021 The beginning of the extended forecast period will continue with near record warm temperatures. Thursday may see the latest 90+ degree temperatures on record for some areas. Widespread 90s across areas east of the Divide with upper 80s across the lower elevations elsewhere. A trough across the Pacific NW will begin to break down the ridge over the next few days and also increase winds across the region as the gradient tightens. The big concern with this will be increasing the fire weather concerns Thursday and even more so Friday. Thursday, the RH will be the slam dunk with very dry air still present ahead of the impending system, but the wind will be marginal as the trough is still progged to remain off the Pacific Coast into Friday morning. That being said, winds will still be gusty enough to potentially warrant fire weather highlights across prone areas. Friday will be the opposite story, with winds being the slam dunk element and the RH being a bit more marginal. Nudged lower on RH in the grids for Friday due to the gusty dry winds ahead of the trough, which likely will drop RH lower than what the best guess of the models is. So, Friday may see more widespread fire weather highlights. Friday also will be quite warm, though not as warm as Thursday. A cold front will move through Friday night, dropping temperatures and bringing some precipitation across the region. Gusty northwest winds and increased dewpoints will occur with and behind the frontal passage, but the exact timing is still uncertain as models are still in some disagreement with this. Saturday, chances of precipitation with and behind the front are possible across the region, but again exact locations and timing of this are still uncertain at this point in the forecast. Sunday, some precipiation is again possible across the region as the unsettled pattern continues. More seasonal temperatures and general northwest to westerly flow will dominate the remainder of the forecast period. Some isolated precipitation will remain possible as shortwaves in the flow could impact the region. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 550 PM MDT Tue Sep 7 2021 Other than MVFR visibility due to wildfire smoke at a few terminals, all locations will be VFR through the forecast period with high pressure in control. This will limit wind with 10 kts or less at all sites through 00Z/Thursday. && .FIRE WEATHER... Issued AT 242 PM MDT Tue Sep 7 2021 A ridge of high pressure in the Great Basin dominates the regional weather picture through Thursday. Temperatures gradually warm the next few days, peaking Thursday with record or near-record warmth. Lower elevations east of the Continental Divide will see readings in the 90s and it is possible any records set could be the warmest seen that late in the summer. To the west, seasonal daytime highs average 70 to 75. Expect highs Thursday to be 10 to 15F warmer than that. Gusty wind does not appear to be much of an issue through Thursday with the high pressure in control. Other than some high clouds and smoke from western US wildfires, there will be little cloud cover through Thursday. The ridge begins to breakdown Friday and moisture returns to western Wyoming in southwest flow aloft. This will lead to at least isolated showers and thunderstorms across western Wyoming. However, a dry lower atmosphere may take a bit to moisten, so these showers and storms may not provide much rainfall. Associated cloud cover and cooler temperatures aloft combine to help cool the far west several degrees. The story may be different across southwest and central Wyoming. Temperatures, while a tad cooler, are likely to remain well above normal for this time of year. The favorable southwest flow aloft will lead to increasing wind of 15 to 30 mph, particularly across the High Desert District and central Wyoming. Given the low relative humidity, Friday is a prime candidate for elevated to critical fire weather conditions. Temperatures trend closer to seasonal averages for Saturday with a slight chance of showers and thunderstorms regionwide. The gusty wind and slightly above normal temperatures may return for Sunday. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CNJ LONG TERM...Fisher AVIATION...Jones/VandenBoogart FIRE WEATHER...CNJ