Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/02/22

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
820 PM CDT Thu Sep 1 2022 .UPDATE... Issued at 818 PM CDT Thu Sep 1 2022 A pre-frontal trof and extreme heat helped kick off a few thunderstorms this evening. But, with the loss of diabatic heating, the storms are quickly dying. As the main front moves in late tnt, a few more showers and storms appear possible, and that activity remains evident in the latest runs of the HRRR model. Temperatures overall look fine. && .SHORT TERM...(This Evening through Friday Night) Issued at 322 PM CDT Thu Sep 1 2022 The main challenge in the short term is fire weather on Friday. For tonight into Friday morning, a number of the latest CAMs develop a few showers and perhaps a weak storm (HREF mean MUCAPE of ~500 J/kg) across northeastern SD and west central MN tonight into Friday morning, in response to an incoming cold front. However, this activity will be interacting with dry air, so maintained less than 20% PoPs through this time. The cold front will track across the CWA from northwest to southeast through the morning. Due to a good surge of CAA, northerly winds within the first couple post-frontal hours may gust in excess of 35-40 mph. Thereafter, winds will lessen, but should remain somewhat breezy through the afternoon (20-25 mph gusts) due to good mixing with very dry air in place during peak heating. Blended in the HREF to get lower dewpoints Friday as well, which led to minimum RH values in the upper teens to mid 20s across central SD. Opted against a fire weather headline at this time, as the strongest winds are offset from the lowest RH in terms of timing. Recent rains have made for non-critical fuels across portions of central SD as well. High pressure builds in Friday evening, leading to lessening winds, clear skies and relatively cool overnight lows in the upper 40s to low 50s. .LONG TERM...(Saturday through Thursday) Issued at 322 PM CDT Thu Sep 1 2022 Upper ridging will dominate the pattern over the holiday weekend and into the upcoming work week. Most days will see highs well above normal for early September, in the upper 80s to mid 90s Monday through Thursday. The main forecast challenges will be the temperatures, which could exceed guidance during the day and then fall below guidance in the dry air overnight, and fire weather west river. The lack of precipitation over the next week plus the very warm max Ts will lead to quick drying of fuels. Winds will be the deciding factor a few days this week as to fire weather concerns. Sunday and Monday appear to be the days to watch for the moment with a passing dry front and breezy southerly winds. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) Issued at 613 PM CDT Thu Sep 1 2022 Terminals KABR,KATY,KPIR,KMBG VFR skies/vsbys are expected through tonight, along with isolated showers/storms. Winds will turn gusty behind a front overnight. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TDK SHORT TERM...Lueck LONG TERM...Wise AVIATION...TDK
Area Forecast Discussion
National Weather Service Columbia SC
1035 PM EDT Thu Sep 1 2022 .SYNOPSIS... Moisture and precip chances build back across the region Friday as southeast flow increases. This moist and somewhat unstable airmass will then stay in place through the weekend and last into next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Upper level low over southern Georgia this evening. Showers and thunderstorms have diminished but at 02z radar showing a few showers re-developing in the SC coastal plain moving northwest toward the southeast Midlands and CSRA. These showers are associated with east low-level moisture flux...resulting high precipitable water 1.8 to near 2 inches and some lift associated with short wave trough rotating northwest from the upper low. Raised pops again to chance in that region. The model consensus focus scattered light showers/maybe a thunderstorm given some weak instability mainly in the southeast Midlands and CSRA through the overnight. Cloud cover should limit radiational cooling especially in the southeastern counties with lows ranging from the upper 60s north to lower 70s southeast. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Similar setup to today will exist again on Friday, with maybe a bit more moisture. Mid level trough will be pushing into southeastern Canada, and with strong subsidence on the backside of that, will help to strengthen a surface high to our north. As this pushes off the New England coast, expect onshore flow to increase across the region, helping to increase PWs, especially across the southwestern FA. Additionally, the weak shortwave present across southern GA today will be nearer to the CSRA tomorrow. With PWs rising to near 2", expecting scattered to numerous showers to develop again tomorrow afternoon. Much like today, there should be a sharp cutoff between who sees rain and who doesn`t, with that cutoff likely splitting the Midlands. I am fairly confident that the western Midlands and CSRA will see showers/storms, but am not as confident from Columbia and points north and eastward. Highs will likely be near normal, with upper 80s likely everywhere. It`ll probably be warmer in the northeast where sunny skies are more likely to dominate. Overnight lows will end up in the low 70s. I expect some showers to hang on Friday night as well with the weak shortwave finally traversing through the region and to the east. Saturday looks more wet, with higher PWs overspreading the area. MOS Guidance is indicating PoPs in the 45-60% range across the area. We`ll be within good onshore flow across the region, with southeasterly flow noted up to 850 hPa. As a result, ECM and GFS are indicating PWs exceeding 2" across much of the area by Saturday afternoon. Though the shortwave from Thursday and Friday will have pushed east, expectation is that inverted surface troughs along the southwestern side of the surface high will be plenty to force afternoon showers/storms within a moisture rich environment. As a result, going with high end Chance to low end Likely PoPs (50-60%) across much of the area. This will likely keep afternoon temps a tad below normal, with highs in the mid and upper 80s expected. Showers should be slow to diminish on Saturday night, but I expect that they will at some point during the overnight period. Lows will likely end up in the low 70s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Sunday and Monday look like wet weather days again, with scattered to numerous showers and storms possible both days. Setup will remain fairly similar, with guidance maintaining high PWs across the area near and above 2". With weak mid-level troughing approaching from the west, showers and storms are likely to develop across the region both afternoons. Models differ on what happens with this troughing towards mid week, but trends are towards weak troughing remaining across the OH Valley and southern US through the end of the period. If this is correct, we`ll be stuck between the ridge to our south and the trough to our west, with high PWs remaining over us. This will lead to wet weather through at least the middle of next week, with at least isolated to scattered showers/storms expected each day. This seems to be the direction the models are going, and is represented in the forecast. Daily highs should be near to slightly below normal, with lows in the upper 60s and low 70s. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Combination of nearly stationary upper energy and low level moisture flux convergence providing SHRA activity moving NE that appears will affect OGB/AGS/DNL in the near term. CIGs have fallen to MVFR at AGS/DNL at 02z. Latest SREF and HRRR trending more pessimistic with stratus coverage tonight. Will indicate IFR restrictions at all sites. Little overall change in the pattern Friday. Best moisture to favor AGS/DNL area, so will restrict afternoon VCTS mention to those sites. EXTENDED AVIATION...Chance of mainly afternoon thunderstorms, and late night/early morning fog/stratus. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Dodge City KS
614 PM CDT Thu Sep 1 2022 ...Updated Aviation Discussion... .SHORT TERM...(This evening through Friday) Issued at 345 PM CDT Thu Sep 1 2022 The mid-afternoon water vapor loop and RAP analysis showed an elongated shortwave trough extending from northern KS, through southwest KS and south into the TX Panhandle. The best deep layer forcing for ascent was moving into south central KS and adjacent northwest/north central OK, which is where several clusters of thunderstorm activity were found. This included the Red Hills region of southern Comanche County where radar indicated a quick inch or more of rain...generally south and east of Coldwater. As the mentioned shortwave trough continues to move across the Central Plains through the evening, deeper layer subsidence will overspread southwest Kansas, and additional thunderstorm activity is most likely not expected, as a result, across our forecast area. On the heels of this afternoon`s wave will be another upstream wave moving south-southeast through the larger scale pattern. A polar front will be accompanying this next wave, which will become the primary focus for loosely organized thunderstorm activity, first developing across far northwest KS into southwest Nebraska. The 6-8 km AGL winds will be out of the north 30 to 45 knots, which will aid in increasing deep layer shear to support organized multicell structures if not marginal supercell structures at times. That being said, low level moisture will be decreasing the farther west one goes into western Kansas, thus the primary risk from the strongest storms would most likely be in the form of damaging wind gusts. Most of the convective-allowing models (CAMs) show somewhat organized convection moving south across much of southwest Kansas through the late evening hours, hence the increase in POPs to 30 to 40 percent over a larger portion of our forecast area. On Saturday, the front will clear the southwest Kansas region with slightly cooler temperatures in the afternoon on northeast winds. Renewed thunderstorm activity late Saturday and Saturday Night would be confined to areas south of southwest Kansas into the West Texas/Texas Panhandle/northwest Oklahoma region. .LONG TERM...(Friday night through Thursday) Issued at 345 PM CDT Thu Sep 1 2022 The theme of dry and warmer than normal will continue through next week as the dominant upper level high will persist across the West, and this will keep western Kansas in a northeasterly upper level wind pattern. Additional shortwave troughs will round the upper ridge and move south/southeast across mainly the eastern Great Plains, and this is where the focus for rain and thunderstorm activity will most likely be early next week. The southwest Kansas forecast will be dry from Saturday Night through early next week. A deeper polar jet stream trough will likely develop across the Pacific Northwest region toward the end of the forecast period. There is also some indication from global deterministic models, as well as ensemble systems like GEFS and EPS, that a tropical system of some fashion may move north through the Gulf of California/Baja California which may also aid in breaking down the persistent upper level high out West. This is 6+ days away, though, so there remains tremendous uncertainty regarding how fast/significant the upper high out west will really break down, leading to a change in our sensible weather out here across southwest Kansas. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 602 PM CDT Thu Sep 1 2022 Scattered ceilings with cloud bases as low as 4000 to 6000ft AGL will be possible from 00z and 03z Friday as few isolated thunderstorms dissipate between Dodge City and Hays. The winds overnight will be south southeast at 10 knots or less. Towards daybreak these light winds along with some increasing near surface moisture may result in patchy early morning fog and/or low stratus at 1000ft or less based on the latest BUFR soundings and HREF visibility forecast. The area with the highest probability for this to occur will be near and east of the Dodge City area. After 14z what fog that does develop will give way to VFR conditions as south winds at 10 knots or less continues. && .PRELIMINARY POINT TEMPS/POPS... DDC 66 96 62 91 / 10 10 30 10 GCK 64 96 60 89 / 0 10 30 10 EHA 63 96 61 90 / 0 10 20 10 LBL 64 96 62 91 / 10 10 20 10 HYS 66 96 61 88 / 10 20 30 0 P28 68 96 65 92 / 10 10 30 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...Burgert
Area Forecast Discussion
National Weather Service Goodland KS
547 PM MDT Thu Sep 1 2022 .SHORT TERM...(This evening through Sunday) Issued at 215 PM MDT Thu Sep 1 2022 Upper ridge centered over the Great Basin will be controlling feature for the short term period. Main concerns will be on Friday, as a cold front trailing from a northern plains low will initiate scattered thunderstorms as it moves through the area. The hot and dry environment will once again favor wind and blowing dust as the primary hazards, although there may be just enough instability and shear to support a more organized updraft capable of producing marginally severe hail. There are some timing differences among the CAMs. The HRRR is the fastest of the models, with most of the convection south of the area by 00z, while NAMnest has storms lingering through about 03z. Hard to discount either solution at this time, so will smooth out the POPs to try to account for the differences. In addition to the thunderstorms, fire weather will be a concern, mainly in western and northern parts of the area. Northeast winds will increase behind the front with occasional gusts to 25 kts possible. Relative humidity will drop to the 15-20% range as well. Coordinating with surrounding offices, will message near critical conditions and not issue any highlights, though it will be close. High temperatures will be in the upper 90s and lows Friday night in the 50s. The weekend will be quiet with no precipitation expected. Temperatures will be slightly cooler on Saturday behind the front with highs in the upper 80s, rebounding to the lower 90s by Sunday as the ridge nudges eastward. Low temperatures will be in the 50s. Keeping an eye on fire weather, humidity will be too high on Saturday for any concerns, but does drop to near 20 percent on Sunday with light winds, suggesting the possibility of elevated conditions if the dew points can mix out a bit more. .LONG TERM...(Monday through Thursday) Issued at 1254 PM MDT Thu Sep 1 2022 Next week continues to look warm and relatively dry across the area. There could be a chance for storms around the mid part of the week but there is uncertainty as to whether or not moisture will move into the area and where the better forcing will be in the Plains. The upper level pattern continues to be forecasted with a ridge across the Western CONUS, tilting towards the Great Lakes Region. Meanwhile, the cut-off low from the trough over the Eastern CONUS is still forecasted to be confined to near Texas before moving off to the northeast later in the week. This will keep the area dry and warm to start the week with more northerly flow aloft over the area and a lack of disturbances moving through. Monday and Tuesday are forecasted to see highs in the upper 80`s and 90`s under mostly clear skies. Lows should drop to near or just below 60. Around Wed-Thur, there is a small chance for storms as the upper pattern changes with the shift in the cut-off low. However, guidance differs on how the pattern will evolve. Some suggest that the ridge will amplify over the Central CONUS while others suggest a small disturbance will move through from the northwest. Ensemble guidance isn`t too optimistic about a disturbance moving in from the northwest until outside the forecast period, but the feature could be small enough to be muted in the ensembles. The other factor will be the availability of moisture. Compared to yesterday, guidance has backed off and shifted the moisture surge from the south further east away from the area except for the GFS. If moisture doesn`t advect in from the south, storm development would be unlikely short of maybe an isolated storm or two in the afternoons. Given the ensemble pattern and most guidance leaning dry, that is the current forecast with sunny conditions and highs in the 90`s. However, if a disturbance moves through and/or moisture advects in from the south, conditions would instead be cloudier and cooler with increased chances for storms. If a disturbance does move through with the moisture fully advecting in from the south, there could even be severe storms or heavy rain totals. Will have to watch as this scenario is currently unlikely based on model trends and the suggested upper pattern. Another thing to watch is the potential for near-critical to critical fire weather conditions if the drier and warm conditions prevail. However, the surface pattern without a disturbance would likely be benign with a broader pressure gradient across the area leading to relatively light winds around 15 mph or less which would inhibit critical fire weather conditions. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 540 PM MDT Thu Sep 1 2022 VFR conditions will prevail at MCK and GLD through the 00Z TAF period. Mostly clear skies will become partly cloudy after 22Z Friday afternoon with light south winds increasing and becoming gusty as they turn to the northeast. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...024 LONG TERM...KAK AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
902 PM CDT Thu Sep 1 2022 .UPDATE... Issued at 902 PM CDT Thu Sep 1 2022 No major changes to the going forecast with only minor tweaks to temp and sky trends. Am still thinking that sprinkle/isolated shower chances are pretty low across northwest parts of the forecast area overnight toward daybreak. The trajectory of the shortwave trough moving NE across south-central IA keeps it to the northwest. Satellite shows an expansion of mid level cloud cover eastward from the wave in the presence of increasing mid level warm advection. 00z DVN sounding shows steep mid level lapse rates which will spread northeast along the IL/WI border overnight with the warm advection. A fair amount of dry air remains below the mid cloud base which, combined with the deeper forcing associated with the wave remaining to the west, suggests that it would be pretty tough to get any kind of showers to develop this far east. Still cannot rule out some sprinkles from the warm advection with the favored area being along and west of I-39 and perhaps along and north of I-90 a bit to the east of I-39. MDB && .SHORT TERM... Issued at 218 PM CDT Thu Sep 1 2022 Through Friday... Main items of note: * Small chance for an isolated shower overnight far NW CWA * Very warm and breezy on Friday While September marks the start of meteorological fall, Friday`s weather (like today`s/Thursday`s) is a reminder that there`s still a few weeks left of astronomical summer. Forecast highs on Friday are a degree or two warmer than this afternoon`s temps. Increasing high clouds have been spilling eastward as a slow moving and moisture starved short-wave treks slowly east- northeast toward the MS River. With modest but persistent south-southwest winds and increased cloud cover tonight, expect milder overnight low temperatures ranging from the mid and upper 60s outside Chicago to low 70s in the city. Most forecast soundings appear too prohibitive for any precip into far north central and northwest Illinois in the pre- dawn hours of Friday. However, a few models are close with a couple hour of near mid-level saturation (around 9-10kft AGL) that could tap into a corridor of steep mid-level lapse rates for spotty high based showers. Given the steep lapse rates, there`s a non-zero chance for a rogue thunderstorm. With most guidance leaning dry, kept PoPs non-mentionable in the northwest, but may need to entertain at least sprinkles mention if observed sounding data suggests sufficient moisture for spotty showers. Friday should see a gradual scattering of the mid and high clouds with south-southwesterly flow strong enough to keep lake breeze development at bay, with possible minor exception of a slight south-southeast bend to the wind along the far north shore. Expect gusts up to 20 mph or so, with potential for a few hours toward mid day of gusts up to 25-30 mph from a departing modest low-level jet. With the warmer start to the day and progged 925 mb temps again in the low-mid 20s Celsius, forecast highs are in the upper 80s for many locations and up to 90-91F in the heart of the Chicago urban heat island away from the lake (explicit range of 85-91F). Dew points in the low-mid 60s will mean a slightly humid feel to the already well above normal temps, appropriate heading into the start of the unofficial last weekend of summer. Castro && .LONG TERM... Issued at 314 PM CDT Thu Sep 1 2022 Friday Night through Thursday... Our weekend kicks off with a quiet Friday night. Over the past couple of days, guidance has been indecisive on whether or not a few isolated showers would be reeled in from the northwest Friday evening and night as they form along an approaching cold front. While it looks likely that showers and perhaps a storm or two will be forming not far to our northwest, our profile simply looks far too dry above 850mb to maintain any showers activity in the CWA and a serious lack of forcing certainly won`t help. The HRRR is perhaps the most aggressive with the rain chances as it has a weak little MCV develop over eastern Iowa Friday evening underneath a supposed buckle in the low level flow. If this solution comes to fruition, then I suppose it`s a possibility that a few light showers could survive long enough to fall on the far northwest CWA, but this is a big outlier. Therefore, slight chances were removed from the forecast to show dry conditions area-wide. Better rain chances arrive on Saturday as the front passes through the area. This boundary is anything but impressive appearing very shallow with gradual forcing. With an 850 mb trough moving over the area, low level lapse rates could get pretty steep by midday. There`s a lot of uncertainty among guidance on how much instability will build up ahead of the front and how low the LFC will drop. The NAM is the most aggressive with as many as 2,500 joules of MUCAPE and an LFC near 900 mb. However, even with a favorable thermodynamic environment, this solution still only supports shallow, short-lived pop-up thunderstorms seeing as the mid-levels on either side of the front remain notably dry and we have, quite literally, no forcing aloft. With such weak flow above the surface, it won`t take long for any showers or thunderstorms to drown themselves out. That is, however, if we can get parcels lifted to their LFC. This also means that any precipitation should hug the front pretty closely with no pre- or post-frontal precip expected. Overall, I don`t expect anything more than a brief period of afternoon showers and thunderstorms, but also wouldn`t be surprised if the area remains dry. Saturday will also be another hot day with continued southerly flow ahead of the front and ample sunshine helping to pull temperatures back into the middle and upper 80`s. Following frontal passage, winds readily shift to NNE and pick up in magnitude as an encroaching High centered up in Ontario tightens up the surface pressure gradient. This will result some sizable waves and hazardous swimming conditions in Lake Michigan beginning Saturday evening and lasting through much of Sunday. These winds will also result in some cooler conditions on Sunday with areas roughly north of I-88 forecast to top out in the middle and upper 70`s. Sunday afternoon, a broad area of low pressure is expected to throw up a swath of showers and light thunderstorms across central and southern IL. Some guidance likes the idea that some of this rain will make it as far north as the southern CWA and into parts of northwest Indiana. Forecast soundings looked reasonably supportive of this so some rain and thunder chances were kept in the forecast for areas roughly along and east of I-57. Conditions then look, for the most part, dry and warm through the first half of the upcoming workweek. A quiet synoptic pattern sets up following the weekend with fairly steady mid and upper level heights and the jet seated well up to our north. However, guidance is all over the place with mesoscale features next week throwing up everything from low level shortwave perturbations to small vort maxes to weak, albeit notable, low level jets. A lack of moisture in the mid-levels should inhibit most shower development. However, a couple of convective afternoon showers or light thunderstorms could be possible when you consider we have no prominent high pressure system or synoptic-scale subsidence and there`s potential for some good diurnally-driven instability to build up. All in all though, it looks like the vast majority of next week, at least through Thursday, will be quiet and rain-free. Temperatures will be rather consistent through the week with highs in the lower and middle 80`s, perhaps a bit warmer come Thursday with some surface warm air advection slated to take place along with steady height rises aloft. Doom && .AVIATION... For the 00Z TAFs... 626 PM...No forecast concerns this period. Southwest winds will diminish under 10kts with sunset this evening and turn more southerly. South/southwest wind directions are expected Friday with speeds increasing back into the 10-12kt range and gusts into the 15-20kt range possible. Winds will diminish under 10kts with sunset Friday evening. There is a small chance for a few sprinkles or a few light showers across northwest IL tonight. cms && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Spokane WA
342 PM PDT Thu Sep 1 2022 .SYNOPSIS... Temperatures have eased a little today before another warmup on tomorrow with more triple-digit heat possible. Slightly cooler temperatures will arrive by the weekend accompanied by breezy winds, elevated fire concerns, and isolated dry thunderstorm chances. Next weeks highs will trend down to closer to season normals. && .DISCUSSION... Thursday afternoon thru Saturday: Today features a 4-9 degree reduction in high temperatures compared to yesterday, but temperatures remain 10-15 degrees above average. This corresponds to high temperatures in the low to mid 90s. GOES-18 CIRA Geocolor imagery reveals a large area of smoke east of the Cascades that will likely stick around as winds are light. The smoke source is from multiple regional and local wildfires. AirNow and PurpleAir sensors have indicated moderate to unhealthy air quality regionwide through the early afternoon, with the worst AQ in the Methow Valley, Wenatchee area, eastern WA, and the northern ID Panhandle. Light winds likely will not disperse the smoke greatly today. Fire activity is likely to pick up Friday and Saturday as winds pick up ahead of the incoming shortwave. HRRR near sfc/integrated smoke depicts increased smoke activity from fires in the Cascades, ID Panhandle, and NE OR staying in our region through the weekend. A heat advisory has been issued for the Columbia Basin, Palouse, Spokane/CdA area, and the Camas Prairie Friday as temperatures will be in the mid 90s to low 100s. There are two weather situations to keep an eye on Friday/Saturday: 1.) Fire concerns: PWATs are set to rapidly decrease through the day Thursday as the ridge builds. NAEFS mean PWATs are indicating they could reach as low as 0.25 inches lee of the Cascades Friday. Relative to `79 to `09 CSFR climatology, those are in the 2.5 to 0.5 percentiles range. These values make sense given the current water vapor imagery looking extremely dry in N CA. Relative humidities are not going to recover greatly tonight (30 to 45% in the higher terrain) given the low PWATs and will certainly reach RFW criteria Friday (widespread 7 to 15%). RFWs have been issued for the Columbia Basin/Palouse/Spokane/ID Panhandle Friday/Saturday given how hot, dry, and unstable it will be Friday and Saturday. 2.) Gusty dry thunderstorms: As the shortwave approaches Saturday afternoon, guidance is hinting at a scenario where moderate elevated instability builds in north Central Oregon Saturday afternoon thanks to a surge in monsoonal moisture. The shortwave forcing looks strong and could initiate thunderstorms that move from NE OR into the Palouse/Camas Prairie/Spokane area Saturday afternoon. Confidence is increasing in this solution as 12Z GEFS ensemble probability of the trough axis being in central OR by Saturday morning is around 90% (which is higher than the 00Z GEFS around 70%). Cannot rule out dry thunder and gusty winds given the dry subcloud layer. /Butler Sunday thru Thursday: Sunday starts with a longwave trof axis oriented north/south over the Gulf of Alaska with a longwave ridge downstream with general axis placement over the Dakotas up into Saskatchewan that translates east some Sunday afternoon. The resulting southwest flow remains void of significant forcing however ensembles suggest a weak moisture feed may have enough southerly orientation to it to allow some upper level moisture to stream up into Eastern Washington and North Idaho Sunday night into part of Monday. It is not accompanied by much forcing so it may just manifest itself as a dry cold front of sorts and bring about a slight increase in wind gusts Sunday afternoon but with lower intensity in comparison to Saturday`s expected wind gusts. Monday afternoon into Tuesday the southwest flow remains with ensembles suggesting no significant disturbances or moisture moving through it so a gradual warming trend remains with a benign forecast of generally clear/sunny skies. Ensembles follow this up with a trof passage Wednesday which is slow to clear and leaves a cool northwest flow on the back edge lingering over the forecast area for Thursday. This allows for a cooling trend starting after Tuesday that may bring temperatures down to near normal or even slightly below normal on Thursday. Smoke from local and regional fires may remain a concern however the prolonged interval of southwest flow aloft should push most of the lofted smoke from regional wildfires to the northeast. /Pelatti && .AVIATION... 00z TAFs: VFR conditions are expected for the next 24 hours. Winds will generally be light and diurnally driven as ridging sets in. Smoke from regional and local wildfires may cause haze at terminals, but no significant visibility reductions are expected. /Butler && .PRELIMINARY POINT TEMPS/POPS... Spokane 58 98 60 86 56 87 / 0 0 0 0 0 0 Coeur d`Alene 56 98 58 86 54 86 / 0 0 0 0 10 0 Pullman 55 98 54 83 50 85 / 0 0 0 20 20 0 Lewiston 63 104 65 91 60 93 / 0 0 0 20 20 0 Colville 51 97 51 89 47 87 / 0 0 0 0 0 0 Sandpoint 52 94 54 84 51 83 / 0 0 0 0 20 0 Kellogg 63 96 62 84 58 84 / 0 0 0 0 20 0 Moses Lake 57 103 60 89 53 90 / 0 0 0 10 0 0 Wenatchee 66 100 67 87 60 90 / 0 0 0 0 0 0 Omak 61 101 64 94 58 90 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning from noon Friday to 9 PM PDT Saturday for Northern and Central Idaho Panhandle (Zone 101). Heat Advisory from noon to 8 PM PDT Friday for Coeur d`Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties- Lewiston Area. WA...Red Flag Warning from noon Friday to 9 PM PDT Saturday for Eastern Columbia Basin -Palouse -Spokane Area (Zone 708)- Foothills of Northeast Washington (Zone 701)-Selkirk Mountains of Northeast Washington (Zone 700)-Waterville Plateau (Zone 706)-Western Columbia Basin (Zone 707). Heat Advisory from noon to 8 PM PDT Friday for Moses Lake Area- Spokane Area-Upper Columbia Basin-Washington Palouse. && $$
Area Forecast Discussion
National Weather Service Norman OK
1059 PM CDT Thu Sep 1 2022 ...New AVIATION... .SHORT TERM... (This evening through Friday) Issued at 233 PM CDT Thu Sep 1 2022 Much of the CWA has received at least a wetting rain today as an MCV pivots slowly east-northeastward along the I-44 corridor. The MCV has had a well-defined stratiform shield around its northern and eastern flanks on radar today, with an area of moderate rain on the western side. This precip shield will continue to move eastward this afternoon, bringing with it steady to moderate rainfall. Amounts should not exceed 1/2 inch within this regime. The MCV has complicated our convective forecast today, as extensive cloud cover has socked in most of the CWA. Northern and western Oklahoma have received more sunshine, and convection has developed in those regions where destabilization has occurred. Do not anticipate convective redevelopment to be too robust across areas that have received extensive cloud cover and rain this afternoon. However, prior to nighttime storms could continue to impact northern Oklahoma where instability is greatest, and with sunshine poking through in western Oklahoma and north Texas, storm development this afternoon is possible there as well. Afternoon storms will contain the potential for flooding and gusty winds, given the persistent tropical airmass. Overnight, the MCV/trough axis will meander eastward until it`s centered over Tulsa. Recent HRRR guidance suggests robust, back- building convective development along I-44 between OKC and Tulsa. The training nature of this convection would be aided by a convectively-enhanced 25 kt southwesterly LLJ. Uncertain whether or not this convection will occur, and if it will remain in our CWA. However, if this scenario occurred the potential for flash flooding would be strong. Bumped low temperatures up a couple of degrees area- wide tonight, because current dewpoints on the Oklahoma Mesonet network exceed NBM low temperature guidance by up to 5 degrees in spots and no significant dry advection is expected. Will The MCV will wander a little further northeast into tomorrow. However, most HREF members still develop showers and storms along and south of I-40 during the afternoon. Will maintain mentions of rainfall in the grids, as the past several days have shown that it doesn`t take much large-scale support to achieve convection initiation in this airmass. Highs tomorrow will recover to near normal. MEISTER && .LONG TERM... (Friday night through next Wednesday) Issued at 233 PM CDT Thu Sep 1 2022 Monitoring tomorrow evening for the potential for a cluster of storms to move southward out of Kansas and into northwest Oklahoma. Depending on how late in the evening these storms arrived, they might be marginally severe. Most CAMs diminish this activity not long after dark. A northerly speed max will pass just to the west of our forecast area on Saturday. This may provide the impetus for another round of storms across the central and southern parts of the forecast area Saturday afternoon. Flooding and water-laden downbursts will remain the likeliest threat with any diurnal activity on Saturday. Following that, global models suggest that a cutoff low will develop and meander across the southern Plains late in the weekend and early into next week. It`s quite possible that this will lead to a repeat of this week`s pattern - enhanced storm chances for much of the area as it passes by to the southwest, and then storm chances across the southern part of the CWA as it settles into Southwest Texas, and then enhanced rain chances whenever it meanders back in our direction. For now, will maintain chances of thunderstorms across southern and eastern counties where the best moisture is likeliest to be. MEISTER && .AVIATION... (06Z TAFS) Issued at 1056 PM CDT Thu Sep 1 2022 A few lingering storms continue southward over southern Oklahoma. Additional convection may develop over central Oklahoma overnight (mainly east of KOKC / KOUN). Stratus is expected to develop over central Oklahoma, resulting MVFR (possibly IFR) ceilings late tonight toward morning. With the recent rains and light winds, fog development on the western edge of the stratus deck will be possible (as well as patchy fog elsewhere). Clouds should clear out gradually west to east. Day && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 81 70 90 70 / 100 50 20 20 Hobart OK 83 71 94 70 / 80 40 20 20 Wichita Falls TX 87 72 92 72 / 50 10 30 20 Gage OK 89 67 95 66 / 20 20 0 20 Ponca City OK 92 69 92 68 / 40 10 10 20 Durant OK 86 72 87 71 / 90 30 50 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ SHORT TERM...04 LONG TERM....04 AVIATION...14
Area Forecast Discussion
National Weather Service Pocatello ID
141 PM MDT Thu Sep 1 2022 .SHORT TERM...Tonight through Friday night. Ridge of high pressure remains centered over the central Great Basin this afternoon. A weak shortwave trough is moving eastward over the top of the ridge. This trough may produce slightly cooler temps for this afternoon and Friday. In fact, the odds of seeing temperatures in the upper 90s are below 10%. Could nearly justify canceling the heat advisory, but with the ridge is expected to amplify over the weekend and the temps on Friday are still near records so will continue the heat advisory. The trough is also producing some breezy conditions this afternoon, winds appear to be holding below advisory levels. Winds look less for Friday as the trough moves into the central U.S. Dry weather will persist through the short term with any convection associated with the trough this afternoon expected to remain east of Idaho. Smoke and haze is the final concern in the short term. Behind this trough, winds will switch to the west- northwest and the HRRR smoke model is showing smoke and haze from fires across the central Idaho mountains moving into east Idaho tonight and persisting into Friday. Valle .LONG TERM...Saturday through Thursday. Models show ridge centered over the central Great Basin extending with the axis extending northward through east Idaho on Saturday. With the ridge strengthening, our highs will be climbing and the NBM 4.0 supporting a 75% chance of temps greater than 95 degrees across the Snake Plain and eastern Magic Valley. Meanwhile, an area of low pressure will be moving northward along the west side of the ridge through Oregon and Washington. This low will move through the Idaho Panhandle and through western Montana by Sunday morning. This will bring another round of breezy conditions to the region for Saturday and possibly Sunday as well. The track of the low is far enough north and the air over our region is so dry that we are not expecting showers or thunderstorms as this system passes by. The threat for record breaking heat will continue into Sunday, Monday and Tuesday with greater than a 60% chance of temps greater than 95 across the eastern Magic Valley and Snake Plain. Model ensembles indicate at least a 60% chance that the ridge will break down Wednesday into Thursday as an upper level trough digs into the Pacific Northwest. Odds that our highs on Thursday will be lower than 90 are around 75% and lower there`s a 25% chance that the highs will be lower than 80. Just depends upon how deep the trough is as it moves through the region. At this time, precipitation chances look slim as much of the moisture will dissipate as the low pushes into the ridge. Breezy conditions are likely for Wednesday and Thursday with NBM 4.1 indicating at least a 50% chance of peak wind gusts greater than 20 mph. Valle && .AVIATION...A bone dry air mass will keep clouds out for not only the next 24/30 hours, but into Sat morning. Thus there is only the slight impact of reduced visibility due to HZ/FU from nearby fires, which should be at its worst when inversions set in and trap the smoke. Wild fires should be active overnight with poor humidity recovery in many locations. So the main driver for FM groups is wind shifting and decreasing for the overnight. The gusty wind started this morning and will continue into the early evening. However, wind is very light starting by midnight tonight and all of Fri under this very strong upper level ridge. Messick && .FIRE WEATHER...Dry trough moving through western Montana brought fairly gusty wind along with the extreme warmth and dryness. The warmth and dryness are not going anywhere until mid-week of next week, maybe. so the main forecast issue is wind. Tomorrow is a very calm, stagnant day, which may cause smoke/air quality issues with little drifting/scouring of the lower atmosphere. Another upper level low makes its approach on Saturday, boosting wind in the central Idaho mountains for Sat, then the Snake River plain/eastern Magic Valley and southern highlands for Sun. For now, have issued a Fire Weather Watch for the central Idaho mountains. Next chance for some moisture appears to be Wed afternoon with the next upper level low. Messick && .PIH WATCHES/WARNINGS/ADVISORIES... Heat Advisory until midnight MDT Sunday night for IDZ051>059-075. Fire Weather Watch from Saturday afternoon through Saturday evening for IDZ422-475-476. && $$
Area Forecast Discussion
National Weather Service Pueblo CO
257 PM MDT Thu Sep 1 2022 .SHORT TERM...(This evening through Friday) Issued at 256 PM MDT Thu Sep 1 2022 Key Messages: 1) Continued warm through Friday. Currently...satellite imagery shows widespread cumulus cloud development over the Mountains this afternoon. A few weak echoes are noted over the Central Mountains, mainly over Saguache County. Areas over the Mountains will likely only see a few sprinkles as these cells pass. Clear conditions exist on the Plains, where temperatures are currently in the upper 80s to mid 90s. Rest of today and tonight...upper level high pressure will continue to spin over the Great Basin, with broad northerly flow across Colorado. Weak energy moving south will keep the threat of isolated light showers and thunderstorms over the Mountains into this evening. Any convective activity should dissipate by sunset this evening, with dry conditions prevailing overnight into Friday morning. Overnight lows tonight will fall into the upper 50s to lower 60s across the Plains, and 40s across the San Luis Valley. Friday...the upper level high will slowly shift east into Utah through the day. Another wave of embedded energy is forecast to drop south across Colorado, leading to an uptick in Mountain convection. Scattered showers and thunderstorms will initiate by mid afternoon over the Mountains. Wind gusts to 40 mph and lightning will be the main storm concerns. Hot conditions will prevail across the Plains, where afternoon highs in the lower to upper 90s are expected. As for precipitation, the latest high-res model guidance holds off on thunderstorm activity on the Plains until late afternoon to early evening. At this time, expected precipitation chances to be nil on the Plains until after 00z/Sat. Mozley .LONG TERM...(Friday night through Thursday) Issued at 256 PM MDT Thu Sep 1 2022 Key messages: 1) Isolated evening thunderstorms will be possible over the plains and along on Friday. Main threat with these storms if they develop would be strong and gusty outflow winds to 50 mph or greater. 2) Only a few PM thunderstorms will be possible over the mountains, mainly the central mountains on Sunday and Monday. 3) Isolated to scattered PM thunderstorms over the mountains will be possible on Tuesday through Thursday, mainly over the southern mountains and Raton Mesa area. There is a slight chance that tropical moisture could enhance thunderstorms over the region by later in the week. 4) Temperatures will be right around the seasonal average or perhaps just slightly above from the weekend and into the end of next week. Detailed discussion: Friday night through Saturday morning... A weak mid level wave with enhanced moisture at the 500-700 mb level will allow for the opportunity for a storm or two to make it back into the central and eastern plains by later in the evening as there continues to be destabilization by this time. With enough residual moisture around in the mid levels, an isolated storm or two over the eastern mountains I-25 corridor or cannot be ruled out. A jet finger of stronger winds aloft at the 300 mb level will also be moving down through central Colorado and the convergent quadrant will be located over the eastern plains, which may also help to fuel thunderstorm development over this area. MLCAPE does not look to be overly impressive, but there will be better bulk shear of around 40 kts in some locations, which might help to strengthen some of the storms. Given some areas of higher DCAPE of around 2000 J/kg, the main threat of a stronger storm will be strong outflow winds of 50 mph or greater. It does appear with a general consensus between the models that storms should be weakening and moving out of the CWA into the very early morning hours on Saturday, which is reflected both in the HRRR and NAMNest to be continuing until around 3 to 4 AM. The NAM12 also keeps some showers around throughout the later hours of the morning (around 11 AM) over the southern mountains but this might be a little bit of a stretch since it appears in many of the other models that are drier by that period in the forecast. The CAPE values do appear to be more favorable at around 1000 J/kg over this area for convective development, so it is possible that if the NAM12 does verify that there may be storms developing around this time. Saturday afternoon through Monday... There will still be enough mid level moisture around behind the passage of the trough to allow for thunderstorms to form and become scattered over the mountains and high valleys by the afternoon on Saturday. There will also be some isolated storms moving out over the San Luis Valley under the northeasterly flow. The ridge is going to continue to build and take on a more positively tilted axis throughout early next week, which will allow for drier air to be advected in from the northeast in the mid levels and suppress the recycled mid level moisture more to the west. Subsidence will also help to hinder the development of any convection and only orographic forcing will allow for a few thunderstorms to be possible over the mountains, mainly over the southern mountains and Raton Mesa area on central mountains on Sunday and Monday. The northeasterly flow aloft, which will be mixed down to the surface in the east and southeasterly flow, will allow for relatively cooler air to be advected in. This will help to allow for temperatures to be closer to the seasonal average, or just slightly above, through Monday. Tuesday through Thursday... Both the ensembles and deterministic models are in close agreement with the ridge continuing to propagate eastward with a positively tilted axis and force a cut off upper level low that moves just to the south and east of Colorado. Depending on the position of this U/L low will determine whether or not there could be some thunderstorms possible over the plains on Tuesday afternoon although it is appearing with the most recent EPS and GEFS ensemble members that the majority of the members keep the low to the south over northern Texas and New Mexico, which will advect in more drier air from the northeast and help to limit the amount of thunderstorm development over the plains. Only isolated thunderstorms will continue to be more confined to the mountains. The troughing upstream over the northwestern CONUS is looking to help prevent the U/L wave from transitioning closer to Colorado. Looking a little ahead in past the forecast period, there are signs of a tropical system moving up from the Gulf of California which may help to advect in more moisture over Colorado by the end of next week and into next weekend and help in increase the chance of PM thunderstorms. However, it is still too far out to be considered reliable at this time and all ensembles, including the Canadian, are showing the brunt of the moisture remaining to the south at this time. Temperatures will remain just around, or slightly above, the seasonal average for this time of year. -Stewey && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 256 PM MDT Thu Sep 1 2022 VFR conditions at all three terminals through the next 24 hours. A few mid level clouds will prevail this afternoon. Wind gusts at KCOS and KPUB of near 20 kts will continue this afternoon, dissipating this evening. At this time, KCOS and KPUB should remain dry through 00z/Sat. A few thunderstorms may be possible at KALS Friday afternoon, but confidence in occurrence is low at this time. Mozley && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MOZLEY LONG TERM...STEWARD AVIATION...MOZLEY
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
947 PM MDT Thu Sep 1 2022 .UPDATE... Issued at 441 PM MDT Thu Sep 1 2022 Based on radar and CAMs, have added some slight chance PoPs to portions of the CWA tonight into Friday morning. Satellite and a peak out the window shows haze from western wildfire smoke, and HRRR smoke forecast indicates this persisting into Friday morning as well, so have added mention in the forecast. && .DISCUSSION...(This Evening Through Thursday) Issued at 243 PM MDT Thu Sep 1 2022 Upper ridging continues across the western CONUS, centered across the Great Basin. Northwest flow also continues across the northern Great Plains. A series of upper waves are crossing eastern MT/WY into the CWA. Ahead of the wave, isolated showers and thunderstorms have developed across northeast WY through the Black Hills area. With inverted V signature in forecast soundings, cloud bases around 12k ft and surface RH in the 10-25% range, most of the precip is falling as virga, evaporating before it hits the ground. Have adjusted isolated pops for this afternoon and evening for coverage, which will end by 03z tonight. A weak cold front will push through tonight, bringing cooler temps the next two days, but still above seasonal averages. Surface high pressure will then park over the Upper Midwest Sunday through the first half of next week. This will bring continued southerly flow and temperatures well into the 90s to near 100 through the middle of the week. && .AVIATION...(For the 06Z TAFS Through 06Z Friday Night) Issued At 947 PM MDT Thu Sep 1 2022 Isolated showers will continue across portions of the CWA tonight, but conditions are expected to remain VFR. Haze from western wildfire smoke will persist into Friday morning as well. && .FIRE WEATHER... Issued at 243 PM MDT Thu Sep 1 2022 Elevated fire weather conditions are expected through early next week due to temperatures well above average and very dry minimum afternoon minimum relative humidities. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ Update...Pojorlie DISCUSSION...13 AVIATION...Pojorlie FIRE WEATHER...13