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

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
513 PM MDT Wed Sep 8 2021 .AVIATION... 00Z TAF CYCLE A few anemic thunderstorms have struggled to develop over the far northern mountains and also the southern mountains of New Mexico, but these short-lived cells will pose more of a gusty wind hazard rather than any appreciable downpours. The potential for these storms will fade after sunset. Another very low probability day for weak, brief- lived storms is expected on Thursday, mainly over the southwestern mountains of New Mexico. Otherwise, faint haze (from CA wildfire smoke) will continue to wrap into much of central and eastern New Mexico, but any visibility reductions should be minimal with VFR conditions prevailing. Finally, hot temperatures will continue with high density altitude readings that could create difficult ascending conditions for some aircraft. 52 && .PREV DISCUSSION...224 PM MDT Wed Sep 8 2021... .SYNOPSIS... Hot and dry conditions will be the rule for much of the next week. Expect record high temperatures to be broken in many locations over the next few days. Haze will continue through Friday as smoke from California wildfires filter into the area. A stray shower or thunderstorm will be possible nearly each day, but the best chance may be across northern New Mexico on Saturday. Even so, measurable precipitation will be hard to come by. && .DISCUSSION... SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)... Patchy low clouds in the vicinity of Tucumcari dissipated by mid morning and now scattered cumulus are observed over the western and northern mountain peaks with a dinky cell northwest of Las Vegas currently showing up on radar. Expect there may be additional isolated cells for the rest of this afternoon over the high terrain but they should be short lived with gusty winds and very localized rain, if any. Any activity should quickly diminish between peak heating and sunset. The upper high center analyzed over Utah this morning is forecast to drift over New Mexico during the next 24 hours. Near record to record breaking heat and lingering moisture may allow for isolated cells to form again Thursday afternoon over the higher terrain, similar to today. Haze from wildfire smoke will continue to circulate through the upper high and over New Mexico but the HRRR near surface smoke forecast is not indicative of any impacts for tonight or Thursday. Overnight lows will be about 5-10 degrees warmer than usual for this time of year. LONG TERM...(FRIDAY THROUGH TUESDAY)... Record to near record heat will continue on Friday as the upper level high centers over NM. Smoke/haze will likely continue as well, at least for eastern portions of the state. The weekend will remain quite hot as the upper high elongates over the southern states. High temperatures will be 5 to 15 degrees above normal. Models are still spitting out a little bit of QPF Saturday and Saturday night across the northern half of the state as a disturbance moves over the top of the ridge. However, confidence is low this will result in measurable precipitation given weak forcing and low dewpoints. Models are struggling early next week regarding the timing and placement of a trough moving over the west coast as well as a back door front that may take aim at eastern NM on Tuesday. Regarding the trough, ensembles show little in the way of this feature and rather keeps the high elongated over the area. Nonetheless, these two features will have to be watched, but for now, Monday and Tuesday look to remain fairly dry with temperatures remaining above normal. 99/34 && .FIRE WEATHER... Upper ridge over Utah today will drift to the southeast and over New Mexico Thursday where it will remain through the weekend, if not into early next week. Near record heat, dry and unstable conditions will be widespread through Saturday before high temperatures start to cool a few degrees as the upper high weakens slightly. Fair to poor overnight humidity recoveries over north central New Mexico tonight and Thursday night will become more widespread over eastern and central New Mexico Friday night and over the weekend while minimum humidities linger near or below 15 percent across northern New Mexico. Isolated short lived showers or a storm or two with gusty winds and little rain are possible over the northern and western peaks through Thursday, and over the peaks near the Colorado border on Saturday. A cold front may impact the eastern plains next Tuesday/Wednesday but forecast models are not in agreement with that feature. Winds through the forecast period will be generally light, so despite the heat, dryness and instability, critical conditions are not expected through the next 7 days. 99 && .AVIATION... 18Z TAF CYCLE Upper high centered over UT and will slide sewd to north central NM during the next 24 hrs. Isold high based convection with gusty winds may be found over the nrn and south central mts, Gila and portions of sern NM prior to 09/02Z. Otherwise haze from wildfire smoke may restrict vsbys at times but generally not below VFR. && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service La Crosse WI
1036 PM CDT Wed Sep 8 2021 .SHORT TERM...(Through tonight) Issued at 242 PM CDT Wed Sep 8 2021 The primary forecast concern for this afternoon and evening is the introduction of showers to the area. GOES water vapor imagery shows a well-formed shortwave trough in northern MN rotating southward within the large-scale upper trough and cyclonic flow regime. Radar showing a nice batch of showers in northeast MN with this wave. Elsewhere, isolated showers are developing north of I-94. Currently there is broken cloud coverage over areas along and north of I-94 in NE MN and NW WI, with scattered cloud cover in SW WI and cooler temperatures in the mid-60s to low 70s across the area. Upstream, colder, ice top clouds and showers can be expected to shift into the area from north to south, mainly in WI per satellite and the RAP 500mb vorticity track. CAMs generally show scattered precipitation along the path of the shortwave trough and reaching northern Taylor Cty WI by 20Z...points southward in the 21-23Z window. Highest lapse rates are located in central and western WI at about 6.8 degC/km and focus along the Mississippi River. These areas will have the best chance for precipitation and some isolated thunderstorms as clouds are deepest. Otherwise, strong to severe storms are not expected through the afternoon and into the evening as there is not enough instability indicated by CAM soundings. Showers are expected to be located primarily in WI but could inch westward into SE MN. Showers are expected to diminish and slowly move out of the area by 02Z. .LONG TERM...(Thursday night through Wednesday) Issued at 242 PM CDT Wed Sep 8 2021 An upper-level ridge sits off to the west over the Rocky Mountains as surface high pressure slides into the region on Thursday. This would bring quiet weather conditions and relatively light winds to the region. Mostly clear skies and a deep, light wind layer overnight sets up a favorable environment for valley fog development Friday morning. For Saturday, slightly warmer conditions are anticipated with afternoon temperatures reaching into the upper 70s to low 80s as 850 mb temperatures increase to around 20C. The upper-level ridge is looking to break down over the weekend as a low pressure system moves eastward through Canada. The pattern becomes more active through early next week with several passing shortwaves. There are periodic chances for precipitation Sunday through the first half of the new work week. With low predictability of the strength and exact timing of these shortwaves from a lack of consensus between model guidance and their ensembles, decided to stick with the blended model guidance (NBM). && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1030 PM CDT Wed Sep 8 2021 VFR conditions expected through the TAF period. The showers have dissipated, however we will continue to see patchy mid clouds fl050-100 through the period. Increased cumulus development is again forecast for Thursday with a few showers possible. Due to the low coverage, will not include in the TAF. Northwest winds generally 5 to 10kts or light and variable. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Dahl LONG TERM...Peters AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Boise ID
842 PM MDT Wed Sep 8 2021 .DISCUSSION... High pressure in the Desert Southwest continues to bring Southwest flow advecting CA and OR wildfire smoke into the region. This has led to above normal (and some record) temperatures throughout the region, but a cooling trend will start on Thursday. Some high level clouds will continue to stream into the area in a line northwest of Burns, OR and McCall, ID. A deep trough will bring a significant shift in weather starting Thursday evening. This will bring intermittent showers and thunderstorms to the Intermountain West into the weekend. The Air Quality Alert is still in effect and the Red Flag Warning will expire at 9pm. No changes to the forecast at this time. && .AVIATION... Smoke continues to persist throughout the area, with higher concentrations in KBNO leading to IFR conditions. Most other regions are experiencing MVFR-VFR conditions. Some high level clouds will continue to stream into the area in a line Northwest of KBNO-KMYL. Intermittent showers and thunderstorms will affect Southeast OR into western ID on Thursday evening. Surface winds: Southwest 10-15 kts mainly over Southwest Oregon becoming light and variable after midnight. Winds aloft at 10k ft MSL: Southwest 10-25 kts. && .PREV DISCUSSION... SHORT TERM...Tonight through Friday night...Smoke is the main feature of current weather with extra input from the Cougar Peak Fire in south-central Oregon. Temperatures continue above normal with the upper ridge still in the eastern Great Basin slowly exiting to the east-southeast. Upstream a Pacific upper trough will move onto the northwest coast Thursday night. Ahead of the trough moisture will increase on south-southwesterly flow aloft through California with some input from a tropical storm near southern Baja California. The moisture and approaching trough will begin isolated thunderstorms in western Baker and Harney Counties late Thursday afternoon. Showers and a chance of thunderstorms will spread eastward to the OR/ID border overnight, with showers beginning in the west central Idaho mountains before sunrise Friday. HRRR shows thunderstorm wind gusts in southern Harney County late Thursday but not nearly as strong as forecast early this morning. Winds are forecast to decrease before reaching southwest Idaho Thursday night. Friday morning eastern Oregon will have widespread showers and a chance of thunderstorms, shifting into western Idaho midday Friday. Northern mountains in Idaho may receive up to a half inch of rain and southern areas up to a quarter inch. High temps Friday will be 15 to 20 degrees cooler than Thursday. The showers and thunderstorms will retreat to Idaho north of the Snake Basin Friday evening, and to Valley County/ID by morning. Air quality advisories remain in effect through Thursday afternoon in southeast Oregon, and through 1 PM MDT Friday in western Idaho. The showers and westerly winds aloft with the upper trough should decrease the smoke on Friday. LONG TERM...Saturday through Wednesday...Weak troughing will remain over the region through the extended period with west to northwest flow aloft. Weak, fast moving, shortwaves will pass nearby in this flow, but timing varies quite a bit among the different model solutions. Our northern mountain zones look to have the best chance for showers through this period. Temperatures in this nearly zonal flow situation will stay near seasonable normals through the middle of the week. Smoke is also likely to remain south of the region with this flow pattern provided no new fires start later this week. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning until 9 PM MDT this evening IDZ402-403. OR...None. && $$ DISCUSSION...SA AVIATION.....SA PREV SHORT TERM...LC PREV LONG TERM....JDS
Area Forecast Discussion
National Weather Service Denver/Boulder CO
900 PM MDT Wed Sep 8 2021 .UPDATE... Issued at 859 PM MDT Wed Sep 8 2021 Another quiet and dry night for the forecast area. Light winds and a very dry airmass will spell good radiational cooling in most locations. Last of the cirrus is passing off to our southeast so clear, but smoky, skies will prevail. The smoke will linger over our forecast area through all of Thursday. High temperatures will be warming with further warm advection, weak lee troughing, and sunshine. Record high for Denver is 94 last set in 1994, and we should break that by a degree or two. && .SHORT TERM...(This evening through Thursday) Issued at 143 PM MDT Wed Sep 8 2021 Very dry air continues to spread across the region with the center of a strong ridge slowly tracking eastward. This feature will continue to push over the state from the Great Basin reducing upper air flow and dropping humidity values through the column. There will be a weak surge of upper level clouds that will spill over the ridge over northeast Colorado into the evening. As the ridge moves east this will help to scatter those out leaving mostly sunny conditions for Thursday. A surface low early Thursday will form bringing southwest surface winds pushing daytime highs back into the mid- 90s across the plains. Smoke impacts will continue with the low level flow combined with the transport winds that will mix down during the day. The latest HRRR guidance reflects this but still seems to be underdone. Surface winds will switch around to the ENE that could help the plains to improve slightly into the evening. .LONG TERM...(Thursday night through Wednesday) Issued at 143 PM MDT Wed Sep 8 2021 Record heat is expected on Friday and perhaps into Saturday as the robust upper level ridge continues to sit nearby. NAEFS 500mb Z and 700mb T climatological percentiles are near or above the 99th percentile across the state, and therefore it`s no real surprise that the forecast high for Denver is well above the current daily record. Our current forecast high of 98F would be tied for the third warmest temperature on record in September (101F in 2020, 100F in 2019) and would shatter the current daily record of 93F (2018). The ridge will sink southward and flatten on Saturday with a weak shortwave approaching from the northwest. Temperatures will likely be above average, but there should be at least modest relief from the heat. PWATs increase to near/above normal values, particularly over the northwest part of the forecast area, and there should be better convective coverage in the afternoon. Despite the slightly cooler temperatures, forecast highs are still near record values for Saturday, with another day in the low 90s expected. Zonal flow establishes itself across most of the region by Sunday, with slightly cooler the upper 80s... for the plains. Guidance suggests there should be just enough moisture/instability for continued afternoon showers/storms, especially for the higher elevations, but most of this precip should be light. Model guidance diverges Monday and beyond, though the general pattern looks supportive of a few weak shortwaves tracking along the periphery of the ridge. If the ridge stays fairly weak, that could mean a few weak cold fronts and temperatures in the upper 70s to low 80s. If the ridge is stronger, above normal temperatures would likely continue for the foreseeable future. We`ll hope for more clarity (and if this forecaster gets to choose, a cooler pattern) soon. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 859 PM MDT Wed Sep 8 2021 Smoke and slant range visibility may force ILS landing conditions at KDEN through Thursday. Surface visibility may dip to around 6SM at times - mainly during the daylight hours. Otherwise, once winds turn back to normal drainage winds tonight toward 05Z-07Z, fairly normal diurnal wind patterns will prevail at 10 knots or less. && .FIRE WEATHER... Issued at 143 PM MDT Wed Sep 8 2021 Elevated fire weather conditions for Thursday with RH values dropping into the teens and single digits across the region combined with unseasonably warm temperatures. Elevated fire danger will continue on Friday with RH below 10% across the majority of the forecast area. Winds are expected to remain fairly weak underneath the ridge, but near Red Flag criteria will still be possible over the windier spots of Grand and Jackson counties. Moisture increases by Saturday with chances for afternoon showers and storms. Humidity values should generally remain above 15% through next week, with a few afternoon showers/storms possible each day. && .HYDROLOGY... Issued at 143 PM MDT Wed Sep 8 2021 No flash flooding concerns through Friday with very hot and dry conditions likely. Chances for rain return to the high country this weekend, but precipitation amounts look fairly light and the overall threat should remain low. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Barjenbruch SHORT TERM...Bowen LONG TERM...Hiris AVIATION...Barjenbruch FIRE WEATHER...Bowen/Hiris HYDROLOGY...Bowen/Hiris
Area Forecast Discussion
National Weather Service Quad Cities IA IL
611 PM CDT Wed Sep 8 2021 ...AVIATION UPDATE... .SYNOPSIS... Issued at 1223 PM CDT Wed Sep 8 2021 A beautiful late summer day was unfolding across all of eastern Iowa, northwest Illinois and far northeast Missouri with plentiful sunshine and a cool northwest breeze. Temperatures as of noon ranged from the low to upper 70s, with comfortable dewpoints ranging from the mid 40s to upper 50s. All of this was brought to us by northwest flow courtesy of high pressure in the western Dakotas, and a surface low in northern Ontario. && .SHORT TERM...(This Evening through Thursday) ISSUED AT 1223 PM CDT Wed Sep 8 2021 [Key Messages] *Beautiful weather over the next 24 hours with temperatures around normal *Breezy northwest winds this afternoon will subside this evening [Discussion] The few things to note for the rest of today are clouds and winds. Latest satellite imagery showed diurnal CU was developing from northern Illinois into central Wisconsin and and southeast Minnesota, which has been fairly well represented by model CU rule guidance and forecast soundings where deep mixing was occurring. Surface winds were also gusty in these areas courtesy of the mixing, which was bringing winds of 20-30 knots down to the surface from around the 850-700 hPa layer. Expect this to continue through this evening before boundary layer decoupling leads to clearing skies and subsiding winds. Some of the more aggressive CAMs including the HRRR and NAMnest attempt to develop rain showers in the CU field from western Wisconsin to northeast Iowa, but this is likely overdone given the amount of dry air to overcome in the low-levels. Expected a persistence forecast through tomorrow as the high pressure over the Dakotas continued building southeast into the Midwest. Overnight lows will drop into the low to mid 50s, with PM highs Thursday climbing into the low to upper 70s. These values are near normal for early September. Will note that some upper 40s will be possible in our northern CWA Iowa counties tonight where there is a higher probability of clear skies and near calm winds. .LONG TERM...(Thursday Night through Wednesday) ISSUED AT 146 PM CDT Wed Sep 8 2021 [Key Messages] *Dry and pleasant through the remainder of the work week *Increasing temperatures and chances of precipitation return this weekend into mid next week [Discussion] Thursday Night through Friday... Aforementioned surface high pressure will continue to build southeast, and will find itself situated over the Ohio River Valley Friday. Southerly flow on the back side of the high will warm daytime temperatures slightly, though conditions will remain quite pleasant with dewpoints remaining below 60 degrees. Expect PM highs Friday in the upper 70s to low 80s. Saturday on... Pressure gradient will begin to tighten on the back side of the surface high as a surface low begins to develop ahead of a shortwave and CVA over the eastern Rockies. This tightening pressure gradient will increase return flow and quickly usher in a warmer air mass and increasing moisture into the area beginning Saturday, with temperatures expected to soar back above normal once again. NBM currently advertises afternoon highs Saturday and Sunday returning back into the mid to upper 80s, with values near 90 or higher even possible across the far south. A warm front is progged to develop across the Midwest Sunday, with the surface low expected to track across it as it remains ahead of the shortwave. Guidance remains mixed on the warm front placement and the subsequent low track, which will be key to our precipitation chances and how warm we get early next week. Ensembles and deterministic guidance remain in agreement of some QPF across the CWA Monday through Wednesday, so have maintained the chances left over from the previous forecast package. Beyond Wednesday, guidance splits on potential solutions with the GFS bringing a cold front through the area Wednesday night and the ECMWF keeping southerly flow in place through Friday. Expect changes to this forecast going forward. && .AVIATION...(For the 00Z TAFS through 00Z Thursday Evening) ISSUED AT 610 PM CDT Wed Sep 8 2021 Beautiful VFR weather with consistently northwest winds 5 to 12 kts will continue through Thursday evening. Visibility will be unlimited (P6SM). && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...Speck SHORT TERM...Speck LONG TERM...Speck AVIATION...Ervin
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
652 PM CDT Wed Sep 8 2021 .UPDATE... Issued at 647 PM CDT Wed Sep 8 2021 Updated to include 00z aviation discussion below. && .SHORT TERM...(This evening through Thursday night) Issued at 247 PM CDT Wed Sep 8 2021 Scattered showers and isolated thunder is currently evident on radar and satellite imagery across northeast Minnesota and west central Wisconsin, with some activity getting into central and east central Minnesota. This should be around into early evening, when the boundary layer will start to cool and we`ll begin to see less forcing from the shortwave evident on water vapor imagery (and RAP analyses) over northeast Minnesota at the current time. The diurnal CU and TCU will move out and/or dissipate during the evening, leaving mostly clear skies overnight into Thursday night as high pressure currently centered over the Plains shifts east across the area. There will be a bit more cloud cover again across the east on Thursday afternoon due to diurnal CU, but any SHRA/TSRA should stay east of our area. .LONG TERM...(Friday through Wednesday) Issued at 247 PM CDT Wed Sep 8 2021 Northwest upper flow at the start of the period will give way to zonal flow over the weekend, which will remain in place into early next week, with a somewhat amplified upper trough proggred to move through the mean flow around Tuesday. The model guidance is in good agreement on the overall evolution of things, but understandably has some spread when it comes to timing and amplitude of individual features. As always, this leads to more uncertainty as we get further into the future, with chance PoPs needed for much of the area from Monday through Tuesday. Prior to then, things look like they should stay dry for most of the area over the weekend. A frontal boundary will drop through Saturday afternoon and evening, but will have minimal moisture with which to work, so expect it to pass through dry. What`s left of that boundary will start to moisten to our south on Sunday, so there`s a slight chance for precipitation over the far south, although guidance has been trending toward keeping that south of our area. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 647 PM CDT Wed Sep 8 2021 Showers have just about exited all TAF sites at initialization time so, aside from a small potential at KEAU over the next couple hours, have kept the TAFs dry through this duration. Mid- and high-level FEW/SCT clouds will continue to drift across the area within downslope flow aloft, with coverage lessening overnight but then increasing a bit after daybreak tomorrow due to atmospheric mixing. Fair wx cumulus clouds in the mid-levels and streaming cirrus aloft. Breezy/gusty NW winds this evening will diminish overnight and back to westerly tomorrow, picking to near 10 kts. KMSP...No additional concerns. /OUTLOOK FOR KMSP/ FRI...VFR. Winds S 10-15 kts. SAT...VFR. Winds W becoming N 10-15 kts. SUN...VFR. Winds N becoming NE 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ UPDATE...JPC SHORT TERM... LONG TERM... AVIATION...JPC
Area Forecast Discussion
National Weather Service Pendleton OR
903 PM PDT Wed Sep 8 2021 .UPDATE...Due to reduced temperatures across the Blues for the day from precipitation activity, pulled overnight lows down a couple of degrees. That being said, shouldn`t be significantly lower as cloud cover is expected to remain overnight to help trap warmth. Trough moves in tomorrow, making Thursday our last warm day before cooler fall-like weather begins to overspread the region. This trough also brings a chance of precipitation for a good portion of the region, with very heavy rainfall possible for the Blues into Wallowas. A marginal risk of excessive rainfall is possible into Wallowa county into Friday. Highs on Friday then are expected into the 70`s for the most part, with lower temperatures for the higher elevations. Goatley/87 && AVIATION...06z TAFs...Smoke is starting to clear out across the region for the evening, though some lingering haze may remain across the region, particularly for areas like RDM. Light winds overnight becoming breezy again tomorrow as a shortwave moves through, with TSRA moving across RDM/BDN and across the Blues by the end of the TAF period. Goatley/87 .PREV DISCUSSION... /issued 433 PM PDT Wed Sep 8 2021/ SHORT TERM...Tonight through Friday night...Several weather concerns are anticipated during the short term period. The weather pattern has been dry and stable for several days with smoke from multiple wildfires contributing to poor air quality, particularly in central Oregon and the Yakima Valley where air quality alerts/advisories are in effect through Thursday. This morning`s shortwave trough that pushed quickly across northern WA had little effect for the forecast area except to tighten the cross-Cascade gradient where breezy winds are occurring in the Kittitas Valley, the Simcoe Highlands, the eastern Columbia River Gorge, and the Lower Columbia Basin. The RHs are in the 20s--not critically low for any fire weather highlights. A much stronger trough is showing definite signs of cyclogenesis on the water vapor loops with a surface low about 400 miles west of Astoria. This low will move northeast towards Vancouver Island tonight with an elongated trough off the coast Thursday. An increasing southwest flow aloft will tap in Pacific and monsoonal moisture and bring isolated thunderstorms to central and northeast Oregon late Thursday afternoon. Showers and thunderstorm will increase in coverage Thursday night and Friday as the upper trough gradually traverses across WA/OR. Fire weather watches have been issued (for more details, refer to the Fire Weather Discussion). Based on inverted-V forecast soundings and the HRRR 10-m wind gust potential of 35-40kts over eastern Oregon, I included gusty winds possible with thunderstorms Thursday night. WPC has Wallowa County included in their Excessive Rainfall Outlook for Friday. The ECMWF Extreme Forecast Index (EFI) places a large portion of eastern Oregon in a potential for very high QPF, and the EFI has proven well in the past in highlighting extreme events. On the other hand, the storm motions look fast enough that slow moving storms are not likely. Main concerns will be heavy rain over burn scars from this season`s wildfires--Elbow Creek, Rock Creek, Black Butte, and Joseph Canyon to name a few. Thursday`s winds will be breezy in some areas, mainly in the southern half of eastern Oregon. Friday will be breezy in the lower elevations, but significantly cooler. Wister LONG TERM...Saturday through Wednesday...Period looks relatively benign as a zonal pattern sets up over the weekend after Friday`s system passes eastward. Ensembles in pretty good agreement on this through at least Monday, before solutions begin to diverge. Some members depict weak troughing heading into Tuesday, while others keep ridging in place. Deterministic models reflect this as well, with the GFS remaining relatively zonal, even depicting some ridging by the tail end of the period, while the ECMWF leans more towards a trough passing through Monday into Tuesday. Given model discrepancies, will stick with NBM for now, which keeps us dry through early next week, with a slight chance of PoPs in the upper mountain zones. Ensembles seem somewhat consistent on another SW flow pattern setting up by the end of next week, which is likely where the NBM is pulling this moisture from. Otherwise, weather looks to be quiet for most of the long term. Temps will be seasonal, hovering around the 70s for much of the forecast area. 74 FIRE WEATHER...Fire Weather Watches are in effect from late Thursday afternoon through Friday afternoon for thunderstorms producing abundant lightning across central and northeast Oregon. The Blue Mountains north of Ukiah are not under the watch, as most of the lightning Thursday night will be to the south and east. Although I am not expecting large wildfire potential, the concerns are mainly new fire starts as well as outflow winds that could be problematic for new fires. Some storms Thursday night and Friday will bring moderate to heavy rain...0.5 inch for some storms...possibly more. As previously stated, previously burned areas from this season`s wildfires will need to be closely monitored for heavy downpours and debris flows. The concerns are mainly central and northeast Oregon, but Green Ridge in southeast Washington should not be ruled out as well. Wister && .PRELIMINARY POINT TEMPS/POPS... PDT 57 86 60 72 / 0 10 10 50 ALW 60 89 61 75 / 0 0 10 60 PSC 60 90 64 77 / 0 0 0 40 YKM 54 88 57 77 / 0 0 0 10 HRI 58 90 62 77 / 0 0 10 40 ELN 55 85 57 75 / 0 0 0 10 RDM 50 85 54 72 / 0 0 30 50 LGD 56 89 58 72 / 0 10 30 80 GCD 57 95 58 75 / 0 20 30 80 DLS 62 88 64 78 / 0 0 0 20 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Fire Weather Watch from Thursday afternoon through Friday afternoon for ORZ611-640-642-644-645. WA...None. && && .PRELIMINARY POINT TEMPS/POPS... PDT 57 86 60 72 / 0 10 10 50 ALW 60 89 61 75 / 0 0 10 60 PSC 60 90 64 77 / 0 0 0 40 YKM 54 88 57 77 / 0 0 0 10 HRI 58 90 62 77 / 0 0 10 40 ELN 55 85 57 75 / 0 0 0 10 RDM 50 85 54 72 / 0 0 30 50 LGD 54 89 58 72 / 0 10 30 80 GCD 55 95 58 75 / 0 20 30 80 DLS 62 88 64 78 / 0 0 0 20 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Fire Weather Watch from Thursday afternoon through Friday afternoon for ORZ611-640-642-644-645. WA...None. && $$ SHORT TERM...87 LONG TERM....74 AVIATION...87
Area Forecast Discussion
National Weather Service Pocatello ID
233 PM MDT Wed Sep 8 2021 .SHORT TERM...Today through Saturday. High pressure ridging breaks down and moves east setting up warm, southwest flow today as a trough moves over northern Idaho. Expect breezy to moderate winds for our northern areas with record to near record temperatures for most of our area. Thursday the flow continues to be breezy, especially for our western and northern areas, out ahead of a system moving into the area. By Friday, an upper level low over OR/WA will bring scattered showers and thunderstorms across the area by Friday afternoon into the early evening. Saturday expect breezy, dry, cooler northwest flow behind an exiting system. However, some models are showing some lingering showers especially over the Island Park area. Expect well above normal temperatures today, record to near record, before becoming below normal by Saturday. TW .LONG TERM...Sunday through next Wednesday. Expect dry conditions through the period with brief periods of breezy to moderate winds. Sunday a dry, breezy trough moves over northern ID and Southern Canada elevating the winds over our northern areas, especially the Central mountains. Models are still indicating another dry, breezy trough on Tuesday, again impacting mainly the Central mountains. Fire weather highlights may be needed depending on relative humidity recovery. Relative humidity will likely be below critical values, especially by Tuesday afternoon. Models then show weak high pressure on Wednesday. Expect 70 to 80s with cooler mountain temperatures through the period. TW && .AVIATION...Expect VFR conditions through Thursday but a chance of some limited visibility restrictions due to smoke down to 4 or 5 miles mainly at IDA and SUN after sunset but for now will keep VFR. Expect clear skies with only the limited smoke visibility restrictions for impacts. Expect more widespread showers and thunderstorms Friday as a cold front moves through Idaho. GK && .FIRE WEATHER...Main impacts through Thursday will be gusty winds mainly in zones 475 and 476. Have red flag warning out through 9 pm tonight for winds and low humidity and have issued for those zones on Thursday for the gusty winds and low humidity again. Left 422 out as humidity may be slightly elevated but will look at it again tonight. Winds won`t be as strong to the south and east today or Thursday. Will see widespread Haines index of 6 through Thursday as well. Main issue Friday will be impacts from upper level trof and associated cold front moving through Idaho. Will likely have widespread shower and thunderstorm activity with this system and may need red flag warnings for thunderstorm coverage on Friday as well. Will see a significant cool down of temperatures Friday and Saturday with minimum humidity significantly higher as well. GK && .AIR STAGNATION...Poor air quality conditions are expected through Friday, at least, across Eastern Idaho due to wildfire smoke from local and regional fires. There is an Air Quality Alert in effect for the majority of the forecast area through Thursday from the Idaho Department of Environmental Quality. The air quality has been determined by the IDEQ to be unhealthy to sensitive groups, and will remain in effect until air quality has significantly improved. The HRRR smoke model brings smoke into the area through Friday. Precipitation Friday and northwest flow aloft by late Saturday will help bring better air quality conditions into the area. TW && .PIH WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 9 PM MDT this evening for IDZ475-476. Red Flag Warning from noon to 9 PM MDT Thursday for IDZ475-476. && $$
Area Forecast Discussion
National Weather Service Phoenix AZ
405 PM MST Wed Sep 8 2021 .UPDATE... Updated Aviation && .SYNOPSIS... Strong high pressure aloft will persist across the Southwestern U.S. through the rest of this week providing above normal temperatures for much of the region. Generally dry conditions will also prevail despite somewhat higher humidity levels. However, slight chances for storms will be possible across far southern Arizona today and across southeast California and the Arizona higher terrain Thursday into Friday. Daily high temperatures through the weekend will mostly range from 105 to 108 degrees across the Arizona lower deserts to a couple of degrees warmer across southeast California and southwest Arizona. && .DISCUSSION... The anomalously strong upper level ridge covering most of the Western U.S. is very slowly drifting eastward and should eventually be centered over the Four Corners area early Thursday before stalling out over New Mexico Friday through the upcoming weekend. Unseasonably warm temperatures across our region will be the main impact through at least the upcoming weekend, but we may also have some isolated thunderstorms to contend with around the outer fringes of the high. This morning saw a very strong gulf surge across SW AZ/SE CA as outflows from a very strong MCV that decayed over northern Sonora pushed northwestward up the Gulf of California into the region. Yuma airport recorded a peak gust of 43 mph and 3SM visibility in blowing dust, with dewpoints rising into the mid-70`s across parts of SE CA/SW AZ. Although low-level moisture levels have been improved by this gulf surge, convective activity is non-existent across the region this hours as strong subsidence aloft has produced a couple of mid-level warm layers in the column. Although convective activity is not expected this afternoon/evening at most locations, a PV anomaly tracking westward across extreme southern AZ around the base of the upper-level high center is expected to trigger at least a few T-storms across central/western Pima County late this afternoon/early evening. Right now SPC does have a portion of south- central AZ in a "marginal" area for severe wind gusts, but they do keep this area. Latest HRRR and SPC HREF guidance does some storm development across Pima County, but with only some isolated storms making their way into SE Yuma/extreme SW Maricopa Counties.A greater threat is strong outflow winds/blowing dust impacting motorists on I- 8 between Dateland and Casa Grande, with lesser chances for dust making its way into the Yuma area. The focus of convective activity is expected to shift westward into SW CA as the upper-level high center repositions itself over northern NM, with the flow aloft becoming more southerly. The main mid-level moisture plume is expected to shift westward, with additional moisture being sheared northward from Tropical Storm Olaf into CA. Latest high-res CAMs are indicating T-storm development over the higher terrain of northern Baja CA/southern CA during the midday/early afternoon hours on Thursday. Some of this activity appears it will attempt to push its way into extreme SW Imperial County and into Joshua Tree NP late tomorrow afternoon/early evening. The main threats will be strong outflow winds/brief heavy rains, as the forecast soundings across that region showing a lot of DCAPE (1500-2000 J/kg), but fairly limited moisture (PWATS in the 1.00-1.20 inch range). Perhaps the bigger story the next couple of days is the very hot temps. 500mb heights in the 592-595dm range are expected to allow temps into the 106-111 degree range today and Thursday. The hottest temps are expected over parts of Riverside County today, then shift eastward into Maricopa County on Thursday. The latest NBM now shows a 30% probability of Phoenix reaching its daily record high of 110 degrees and a 67% probability of reaching 108 or higher on Thursday. Thus the Excessive Heat Watch that was in effect for the Phoenix metro area has been upgraded to an Excessive Heat Warning. As the ridge re-centers itself over New Mexico Friday into the weekend, temperatures should lower a couple degrees starting Friday, but remain several degrees above normal. A return to High HeatRisk potential is looking more likely for Sunday into Monday as further drying of the boundary layer and a slight westward shift of the upper level ridge will likely allow daytime highs to rise back to around 110 degrees. The latest NBM output has tightened the spread in temperature guidance for Sunday and Monday, with widespread readings near 110 degrees looking very likely on Sunday with slightly less likelihood on Monday. Either way, the unseasonably warm conditions are likely to prevail through at least early next week with little if any chance of rain. && .AVIATION...Updated at 2305Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Skies will remain mostly clear through Thursday evening with thunderstorm activity well outside any influence to the Phoenix terminals. While a very light SW wind will be most common this evening, highly variable directions are likely before settling on an E/SE heading late evening and overnight. Winds will struggle to turn to S/SW Thursday afternoon, and in many cases may only become light and variable versus making a distinct shift. Southeast California/Southwest Arizona including KIPL and KBLH: Winds will generally retain a southerly component through Thursday evening under mostly clear skies. Thunderstorms are not expected to directly impact either terminals, however there is about a 10-20% chance an outflow boundary could enhance/reinforce SE winds overnight. There may be periods of nearly calm or variable winds through the period. && .FIRE WEATHER... Friday through Tuesday: Strong high pressure will dominate over the Southwestern U.S. through the weekend and likely into early next week providing generally dry conditions and above normal temperatures. Chances for showers and thunderstorms will be very limited through the period, especially over the Arizona lower deserts where chances will be less than 5%. High temperatures are likely to run a few degrees above normal throughout the period with some lower desert areas potentially approaching 110 degrees. Min RH levels will range from 15-25% through Saturday with readings dropping to 10-20% starting Sunday, while max RHs generally range from 35-55% (locally higher). Winds will overall remain light through the period while following typical diurnal patterns. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Warning from Thursday morning through Thursday evening for AZZ537-540>544-546-548>551. CA...Excessive Heat Warning until 8 PM PDT Thursday for CAZ561-570. && $$ DISCUSSION...Percha/Kuhlman AVIATION...18 FIRE WEATHER...Kuhlman
Area Forecast Discussion
National Weather Service Pueblo CO
316 PM MDT Wed Sep 8 2021 .SHORT TERM...(This evening through Thursday) Issued at 314 PM MDT Wed Sep 8 2021 ...Hot With Lots of Smoke and Record High Temperatures Tomorrow... ...Sensitive Populations Are Encouraged To STAY INSIDE TOMORROW If At All Possible... Currently... Another warm and sunny day across the region at 2 pm. Temps were in the 80s across all of the plains and around 80F in the valleys. Hazy skies were noted region-wide per web-cams and surface obs. Rest of Today into Tonight... With the large 500 mb closed high building over us, very dry air will be moving over the region. This is clearly indicated by the forecasted humidity and PWAT charts over the greater southeast Colorado region. With sinking air in the midlevels, temperatures tonight across all of the region are going to be rather (relatively) uniform with 50s in the plains, 40s in the valleys and rather warm mins in the 30s and 40s mtns. Smoke will be with us through tonight, but it will decrease overall somewhat this evening before pushing back towards sunrise. Tomorrow... It is going to be hot with quite a bit of smoke. The most densest low level smoke is forecast by the HRRR near Surface Smoke product to be over the greater I-25 corridor over southeast Colorado tomorrow, with values of 30-40 ug/M^3. Record high temps are forecast to be broken tomorrow by 2 to 5 degrees as the San Luis Valley will be in the upper 80, mid 90s for Colorado Springs and temps approaching/reaching 100F in Pueblo. Alamosa`s ALL TIME September record high is 89, and we are forecast to reach that value tomorrow. For more Climate information, please go to: and then click on the LOCAL DATA/GRAPHS tab for climate information (including all record temps) for Colorado Springs, Alamosa and Pueblo. Due to the combination of the heat and smoke in the air, it is recommend to stay inside tomorrow as the air is likely not going to be all that healthy across the region. Please monitor air quality forecast by the Colorado Department of Health and Environment for more information. .LONG TERM...(Thursday night through Wednesday) Issued at 314 PM MDT Wed Sep 8 2021 Friday... Diving into the long term period, conditions look to be hot and dry early on. A large upper level ridge and high pressure system will be sitting right on the Colorado and New Mexico border. This high pressure system will bring an area of synoptically sinking air over the region which will inhibit any chances of precipitation. The system will also continue to advect modest low to mid level moisture into the region, which will also help to limit any type of precipitation development. There is a chance of an isolated rain shower/thunderstorm over the western mountains during the afternoon given orographic forcing from southwesterly winds and a slow moisture increase over that area. The most impactful weather from this high pressure system will be the increase in temperatures in response to the strong system being directly over the area. Daily high temperature record values will likely be broken Friday afternoon, with some places possibly setting an all time record high for the whole month of September. Saturday... Saturday will bring the first solid chances of precipitation and a slight cool off to southern Colorado. An upper level short wave disturbance will pass to the north of the area throughout the day. This small wave will bring increased dynamics to the area, but the more focused forcing of this system will stay to the north thanks to the strong ridge still to south of Colorado. This disturbance will shift winds to become more westerly aloft and advect in a modest increase in low to mid level moisture into the region. Given the slight uptick in moisture, orographic lifting from westerly winds into the mountains, and the modest increase in upper level forcing, precipitation is expected to develop over the mountains. The precipitation will start over parts of the Continental Divide late in the day, and push eastward, following the upper level forcing east. At the surface, a weak cold front is expected to drop southward over the region as well. The cold front won`t drop temperatures drastically, but will help to cool the area down enough so that record daily highs are not being broken; the area will still be above average though in regard to temperatures. Sunday - Wednesday... The GEFS and EPS ensembles continue to agree with the overall evolution of the atmospheric flow heading into next week. Sunday through Monday, the ridge sitting over the region begins to flatten out for a short period. This flattening will help to keep weather conditions relatively quiet for the Pueblo CWA. The position of the upper level high pressure during this period though would continue to allow for a stream of smoke to be advected toward Colorado, and more hazy skies would be possible. On Tuesday, a trough begins to dig southward over parts of the central plains of the US. This will help to usher in another cold front over the area. With passage of the cold front, surface winds will become easterly and an upslope regime would be expected. This would allow for precipitation to develop along the eastern mountains during the late afternoon and evening. On Wednesday, the ridge begins building back over the western half of the US. This will start to push in drier air into the area and precipitation chances will decrease in response to that. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 314 PM MDT Wed Sep 8 2021 Hazy/smoky conditions are likely during this forecast time period at all 3 taf sites, KPUB, KALS and KCOS. MVFR conditions will be possible at times due to the haze/smoke. The lower level smoke is expected to be most dense tomorrow afternoon per HRRR smoke forecast product. Surface winds will generally be light and diurnally driven. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HODANISH LONG TERM...SIMCOE AVIATION...HODANISH