Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/04/21

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
602 PM MDT Fri Sep 3 2021 .AVIATION... 00Z TAF CYCLE Upper ridge axis to build westward, becoming oriented from west to east across NM. Sfc boundary over ne NM to move little until aft 02Z when it begins to move south. Showers and thunderstorms this evening will be mainly east of I-25, but light showers could impact KAEG and KABQ through 02Z. VFR conditions likely to remain, though. There may be MVFR cigs and light precipitation associated with the surface boundary after storms dissipate. Showers may linger through the night in the southwest. An active day is forecast Saturday with widespread showers and thunderstorms. && .PREV DISCUSSION...242 PM MDT Fri Sep 3 2021... .SYNOPSIS... Daily rounds of afternoon and evening showers and thunderstorms will continue through the weekend. The stronger storms will be capable of locally heavy rainfall and flash flooding, especially those storms along and east of the central mountain chain. A break in the monsoon action arrives on Labor Day as drier air takes hold of the area through the work week. Most locations look to remain dry this upcoming week while high temperatures rise. && .DISCUSSION... SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)... The existing plume of moisture will become increasing stretched from west to east over the state. Dew points have been slow to mix out so far this afternoon over northwest New Mexico but isolated activity observed there doesn`t seem to be very long lived. No plans to make any changes to the current Flash Flood Watch. The boundary which was located over southeast Colorado this morning drifted into northeast New Mexico but was losing definition this afternoon. It may sag back into northeast New Mexico tonight with areas of low clouds and light precipitation if the RAP13 is right and which the NAM12, HRRR and HREF hint at. The HREF has backed off on the overnight convection it was forecasting, with the majority now focused south of I-40 and west of I-25. The previously mentioned boundary will make more progress into eastern New Mexico Saturday and Saturday night, leading to more widespread activity along and east of the central mountain chain, as well as high temperatures a few degrees cooler on Saturday. There will be potential for locally heavy rainfall, but taking the consideration of Flash Flood Watches one day at a time. LONG TERM...(SUNDAY THROUGH FRIDAY)... By Sunday, a longwave trough crossing the northern Great Plains will weaken the high pressure over east TX and LA. Meanwhile, the H5 high over the Great Basin will become the dominant high as it strengthens to about 594dam. Drier air rounds the Great Basin high and begins to filter in from the northwest which focuses the moisture plume along a SW to NE axis across the state. PWATs fall to less than 0.5" across the northwest quadrant of the state, but will remain in the 0.8" to 1.2" range within the moisture plume with the higher PWATs and deeper moisture across the southeast. Another round of scattered afternoon thunderstorms will favor this SW-NE moisture plume. Locally heavy rainfall also can`t be ruled out, especially across south central and southeast NM where the deepest moisture aided by moist return flow will reside. Unfortunately, the moisture and precipitation trends aren`t favorable through the remainder of the forecast period as deterministic models and ensembles are in very good agreement with the H5 high becoming the dominant feature. By Labor Day, the high continues to strengthen to about 596dam, and drier air continues to push farther southward. The high gradually migrates eastward this week, and as it does so, PWATs will continue to fall areawide with moisture values around half an inch for most by Tuesday or Wednesday. With the high building over NM, this also initiates a warming trend with high temperatures 5 to 10 degrees above normal by mid-week. Most locales will remain dry this week outside of an isolated storm or two in the Gila. There`s potentially some hope for moisture advection next weekend as models try to depict another trough moving inland into the western CONUS and the high migrating back over OK/TX. But as expected this far out, models and ensembles aren`t resolving this feature very well. Stay tuned. 15 && .FIRE WEATHER... Showers and storms will remain active through Sunday. During this time, locally heavy rainfall will be most likely along and south of I-40 and along and east of the central mountain chain, while drier air continues to seep into the northwest part of the state. Cell motion for the rest of this afternoon and tonight will be from southwest to northeast or west to east. Cell motion Saturday will be west to east over the northern quarter of the state, with lighter and more variable movement elsewhere. A ridge of high pressure aloft will strengthen over the Great Basin and into New Mexico next week. This will result in drier and warmer weather with high temperatures several degrees above normal. Showers and storms will be hard to find Labor Day through at least Wednesday and high Haines will be widespread over western and northern New Mexico. Winds won`t be strong enough to trigger critical conditions though. Some moisture may attempt to seep back over the western mountains late next week. Widespread fair to poor ventilation is forecast Saturday through Labor Day. && .ABQ WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until 8 PM MDT this evening for the following zones... NMZ226-239-240. && $$
Area Forecast Discussion
National Weather Service Dodge City KS
521 PM CDT Fri Sep 3 2021 .MESOSCALE DISCUSSION... Issued at 514 PM CDT Fri Sep 3 2021 Key Messages... Thunderstorms over far southwestern Kansas have intensified and could produce large hail and damaging winds. Technical discussion... Outflow from storms to the east has resulted in 15-20 kt easterly winds across far southwestern Kansas. This has locally enhanced the moisture and shear profile across Morton and Stevens counties. Large hail to ping pong size is the main concern with these storms. Later this evening, heavy rains will be a concern farther east as upscale growth occurs. && .SHORT TERM...(This evening through Saturday) Issued at 100 PM CDT Fri Sep 3 2021 Thunderstorms are likely again tonight as short range models indicate an upper level shortwave trough moving out of the Colorado Rockies into the high plains of eastern Colorado and western Kansas this evening. Near the narrow corridor of higher instability with surface based CAPE values up to 3000 j/kg has developed on the cool side of a stalled out front where very high dewpoints in the lower 70s reside. Deep layer shear is supportive of supercell storms given the 180 degrees of directional turning from the surface to mid levels despite the rather weak speeds. However, low level shear is weak from the surface to 1 km AGL. Therefore, the tornado threat is low, although a brief spinup cant be ruled out due to low level enhancement of the shear due to outflow boundaries from previous storms. Large hail to quarter size is expected but could possibly be larger with any brief supercell structures. The main concern is heavy rain and possible flooding along the southern tier of counties north of the front where several storms could train over the same area.urface, a quasi- stationary frontal boundary will remain situated near and along the Oklahoma border with a prevailing east-northeast upslope flow spread across central and much of southwest Kansas. Meanwhile, a rich moisture axis with surface dewpoints in the mid 60s(F) to near 70F will persist from northern Oklahoma northwest into south central Kansas, then westward along the frontal boundary. Thunderstorm development is likely late this afternoon in an axis of increased low level convergence associated with the aforementioned frontal boundary as a series of H5 vort maxima kick eastward through the Western High Plains in conjunction with peak daytime heating. Despite a relatively weak flow aloft, favorable enough directional shear combined with MLCAPE values upward of 2000 to 2500 J/kg will support the potential for strong to marginally severe storms through the evening hours. An isolated tornado or two cannot be ruled out as well. Additionally, model soundings show a very moisture rich environment with PW values upward of 2 inches or so across southern portions of southwest Kansas into south central Kansas. With storms expected to spread slowly eastward along and north of the boundary, and potentially training, extended periods of heavy rainfall could occur leading to possible localized flooding impacts. As for temperatures, much of central and southwest Kansas will remain on the north side of the quasi-stationary frontal boundary tonight. Factoring in areas of lingering precip, look for lows generally down into the 60s(F). Due to increased cloud cover early in the day, expect highs only up into the mid/upper 70s(F) to possibly the lower 80s(F) Saturday afternoon. .LONG TERM...(Saturday night through Friday) Issued at 122 PM CDT Fri Sep 3 2021 A much drier pattern is still expected to take hold across the region Sunday as medium range models show upper level ridging beginning to build in the Intermountain West, then amplifying further as it slowly shifts east out into the Western High Plains by mid-week. Combined with a fairly weak flow aloft and the arrival of a cold front by Tuesday that will pull much drier air into western Kansas, very little in the way of precip chances can be expected through at least Wednesday. Temperatures will begin to rebound a bit Sunday as a surface high kicks off to the east through the Central Plains, giving way to a southerly flow across western Kansas. Widespread 80s(F) for highs are expected Sunday afternoon with temperatures pushing the lower 90s(F) Monday. Temperatures are forecast to drop back a little by Wednesday as a result of the projected frontal passage sometime Tuesday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 440 PM CDT Fri Sep 3 2021 Scattered thunderstorms will be near LBL, DDC and GCK for the next few hours through 00z Sat, producing gusty erratic outflow winds, locally heavy rain and lightning. Followed the latest HRRR for convective trends and TEMPO groups. A separate convective cluster is expected to develop NW of GCK around 06z Sat, then propagate southeast producing some aviation impacts overnight through about 12z Sat. VFR will prevail outside of convection, with continued varied amounts of midlevel cloud. After 09z Sat, have high confidence of IFR stratus impacting all airports for several hours Saturday morning, with BR offering some reduction in visibility as well. Stratus will gradually lift to a broken stratocumulus field through midday Saturday. Light NE winds will prevail through this TAF cycle, outside of convective outflow influences. && .PRELIMINARY POINT TEMPS/POPS... DDC 66 80 59 84 / 80 60 10 0 GCK 63 79 57 84 / 70 40 10 10 EHA 64 82 59 85 / 50 30 30 20 LBL 65 83 59 85 / 70 40 30 10 HYS 63 78 57 82 / 70 40 10 0 P28 69 84 62 85 / 70 60 30 10 && .DDC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Saturday afternoon for KSZ045-046- 063>066-076>081-086>090. && $$ MESOSCALE...Finch SHORT TERM...JJohnson LONG TERM...JJohnson AVIATION...Turner
Area Forecast Discussion
National Weather Service Elko NV
302 PM PDT Fri Sep 3 2021 .SYNOPSIS...A mixture of haze and smoke will prevail through the weekend. High pressure across the region will mean hotter afternoon temperatures with 90s by Sunday and Labor Day. && .SHORT TERM...Tonight through Sunday evening. Ridge will be amplifying over Nevada through the Holiday weekend. This keeps the air mass dry and stable. In the short term, the prominent concern will be the continuous haze across most of the northern/central Nevada. Less haze/smoke exists toward the northern Nevada border, but the particulates expand northward tonight. HRRR smoke model showing an enhanced plume reaching Winnemucca, which may lower visibilities. With respect to temperatures, trending hotter with highs reaching the 90s by Sunday for most valleys. .LONG TERM...Sunday night through next Friday. Sunday night heading into Monday ensembles are still in good agreement in having a high over Nevada with an offshore low further west off the coast of California. As time progresses, the offshore low is expected to get absorbed into upper level flow to the north and west, creating a ridge. Under the ridge a strong 595 dm high will remain over western Utah and east/central Nevada. This high sitting over the state ensures dry weather through the first half of next week. By Wednesday the high begins to move off to the southeast as a strengthening trough begins to exit the Pacific northwest. This trough will descend southeast as well, although positioning and timing of this still being ironed out. Some ensembles show the trough being off the shore of California sometime Thursday or Friday. This may aid in moisture surging up form the south. Current 12Z GFS PWAT shows values of 0.75 to 1" creeping up into the county warning area (CWA), by Friday evening. 00Z NAEFS tables continue to show 1-2 standard anomaly for PWAT a week out. Showers and thunderstorms are forecasted Thursday and Friday afternoon for portions of eastern NV. Forecasted highs through the extended period through Wednesday are in the upper 80s to lower 90s, about 10-15 degrees above normal for this time of year. High temps begin to cool down gradually after with the departure of the high pressure. Highs Thursday are forecasted in the upper 80s to near 90 and Friday in the mid to upper 80s. Lows are expected to be in the 40s and 50s throughout next week. && .AVIATION... Mixture of smoke and haze may lower VIS at times at KWMC, possibly into the MVFR category. For the remaining TAF sites (KEKO, KBAM, KTPH, and KELY), the sky will be hazy but VFR conditions should prevail. Surface winds will be generally less than 10 KTS. && .FIRE WEATHER... Dry weather prevails, but gradient winds will be generally be less than 10 mph or less. Hazy conditions persists, particularly northwest Nevada. && .LKN WATCHES/WARNINGS/ADVISORIES... None. && $$ 88/91/88/88
Area Forecast Discussion
National Weather Service Marquette MI
740 PM EDT Fri Sep 3 2021 .SHORT TERM...(This evening through Saturday) Issued at 353 PM EDT FRI SEP 3 2021 High cloud contamination from a slow-moving system upstream in Minnesota has held temperatures into the mid 60s to low 70s across Upper Michigan today. A few echos have been seen on radar this morning and aftn, but RAP analysis soundings continue to show ample dry low and mid levels. For the rest of today and into this evening, expect more of the same with generally ovc skies with a few pockets of sunshine mixed in. Tonight, shrtwv and associated forcing ahead of the wv in Minnesota begin to lift NE through Wisconsin and into the UP. Increasing moisture will begin to saturate the column and expect to see some showers move in sometime after midnight. Models suggest best saturation along with isentropic and theta e ascent will move in around 3Z along the WI stateline, reaching the rest of central and wern UP by 9Z. Expecting some light fog development where showers do develop. By tomorrow, showers taper off early in the day across the west and central, lingering into the middle of the day east. Behind the trof, winds become west northwesterly with some clearing skies. Low-level lapse rates are expected to increase enough that there could be add`l instability showers across the west and central in the aftn and evening, though I think the chances at seeing any lightning or thunder is quite slim. Temperatures should struggle to climb out of the low 60s central and east, but could see some mid to upper 60s west. .LONG TERM...(Saturday night through Friday) Issued at 425 PM EDT FRI SEP 3 2021 Thru the middle of next week, a couple of trofs will amplify se into the Great Lakes region in response to 2 temporary ridge amplifications that occur from the Canadian Rockies toward central Canada. The first is already underway and will drive a trof currently from Manitoba/Saskatchewan/MT into the western Great Lakes on Sun where it will deepen. That trof will then quickly swing out to New England on Mon as the next reaches the Canadian Prairies. With the next ridge building n thru the Canadian Rockies, that trof will amplify into the Great Lakes region for Tue. The upstream ridge will then drift e/deamplify to some degree as a couple shortwaves track off the ne Pacific and then eastward vcnty of the U.S./Canada border. One of those waves should approach the Upper Lakes in the Fri/Sat time frame. For Upper MI, the evolution of the pattern will result in some showery periods associated with each trof, the first this weekend, the second Mon night/Tue and lingering into Wed, and the third at some point Fri/Sat. Climatologically, Sept and Oct are the 2 wettest months of the year for Upper MI, so more frequent episodes of pcpn are right on track with what`s typically expected as the transition toward winter gets underway. As for temps, with the two trofs deepening into the area, temps will be normal to blo normal thru the middle of next week. Ahead of the next shortwave late next week, temps should swing above normal. Normal max temps during this time frame are generally in the 68 to 74F range. Beginning Sat night/Sun, any instability shra should end Sat evening. Attention then turns to the first trof deepening into the Great Lakes which will feature a fairly vigorous shortwave dropping sse to Upper MI Sun aftn/evening. In advance of the wave, a few shra could develop into the w late Sat night. Then, with the shortwave and the associated cold pool aloft arriving, expect isold to sct shra to develop Sun, mainly in the aftn/evening. With the warm waters of Lake Superior boosting sfc and mixed layer T/Td, will likely see shra development over the lake as well, not just over land, particularly late aftn/evening as the cold pool aloft passes over the area. GFS/NAM both show as much or more SBCAPE/MLCAPE over the water than land, and heading into the evening, definitely more over the water than over the land. Could be one of those days to see some photogenic autumn showers out over the water. Waterspout potential could be there as well, but for now, it appears water sfc to 850mb delta-t will be lacking. Not out of the question that there could be a few rumbles of thunder, but MLCAPE over the land is only as high as locally 250j/kg at most. With the NAM, majority of the area is under 200j/kg, GFS even lower. Shra will end w to e Sun night. Will probably be able to slip in a dry daytime on Labor Day as weak shortwave ridging passes across the area btwn the departing trof and the next approaching trof from the Canadian Prairies. 850mb thermal trof will be departing to the e, so expect more diurnal cloudiness e with increasing sun over the w though high clouds will begin to increase there in the aftn. Next approaching shortwave will amplify into the Great Lakes region for Tue. Strengthening waa/isentropic ascent ahead of the amplifying wave will yield shra spreading across the area Mon night. Sfc low will also be deepening as it tracks e, likely passing across Lake Superior. Even after cold fropa on Tue, there will be at least developing instability shra under deepening, cooling, sharpening cyclonic flow into Tue night. Gusty winds to 30+mph may develop across the Keweenaw and near Lake Superior eastward after fropa, depending on track of the low and how much it deepens. On Wed, cool, cyclonic nw flow will likely continue to generate isold to sct shra thru the day. There is more uncertainty in how quickly the trof will depart after Wed. With the the 12z model runs, the ECMWF has joined the GFS/CMC in slowing the departure. Result could be a few isold light shra lingering yet on Thu. Warming/dry weather will follow on Fri as trof departs and heights rise. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 735 PM EDT FRI SEP 3 2021 VFR conditions should continue through this evening at KCMX and KSAW, but conditions will vary between VFR and MVFR at KIWD. An increase in low-level moisture tonight will begin to saturate the lower levels, bringing MVFR to IFR cigs at all terminals. By late tonight for CMX/IWD and early Saturday morning at SAW, -SHRA should begin at all terminals as well. This will likely bring a brief period of MVFR vsbys as well as IFR cigs. Conditions will slowly improve to VFR in the afternoon as drier air advects in from the west behind a weak cold front. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 353 PM EDT FRI SEP 3 2021 Generally light southerly winds tonight are expected to become westerly tomorrow as a trough shifts through the Upper Great Lakes. A cold front is then expected to move in Saturday night into Sunday, which will bring NW winds with gusts up to 25 knots through Sunday aftn west and Sunday evening east. Winds will remain from the NW through Monday morning, before backing W and then SW Monday night. Another trough is expected to pass through Lake Superior on Tuesday before a sfc low develops within the trof near eastern Upper Michigan. As this low develops and deepens overhead, there will be a chance for NW to N gales across the east half of Lake Superior Tuesday night into Wednesday morning. These stronger winds seem likely at this time, but whether or not we see gales will depend on where the sfc low track occurs, so stay tuned to future forecasts. Winds will relax behind this low blo 20 knots by Wednesday night. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JAW LONG TERM...Rolfson AVIATION...Voss MARINE...JAW
Area Forecast Discussion
National Weather Service Pueblo CO
600 PM MDT Fri Sep 3 2021 .MESOSCALE DISCUSSION... Issued at 559 PM MDT Fri Sep 3 2021 Main Forecast Concerns/Challenges: 1) We continue to monitor thunderstorm trends across El Paso County/I-25 corridor hear in the near term as well as over the eastern plains along the Highway 50 corridor later this evening into the overnight hours. 2) A quick summary: Thunderstorm development across El Paso county has stayed somewhat on the weaker side late this afternoon and this looks to continue to be the case over the next couple of hours. However, can`t completely rule out an isolated stronger storm across El Paso county over the next 1-2 hours. 3) Concerns are increasing for more organized development around Pueblo and to the east across the Highway 50 corridor later this evening into the overnight hours. In this location and during that time, all hazards are possible including an increasing risk for heavy rainfall and flash flooding. Latest radar imagery continues to show persistent thunderstorm development across the Palmer Divide, where low level convergence and deep moist upslope flow are in place. An MLCAPE axis of 500 j/kg in this location along with steeper low and mid level lapse rates are supporting these thunderstorms. While instability, focus, and shear are in place, these storms have struggled to strengthen and maintain themselves though. Looking at RAP analysis and even more recent AMDAR soundings out of COS, there are some warmer temperatures aloft that are likely playing a big part in storm intensity at this time. Short term guidance/soundings have initialized fairly well with current conditions, and the forecast soundings over the next couple of hours show these warmer temps aloft maintaining themselves. So, think thunderstorm development will likely continue across the Pikes Peak region, Palmer Divide and into other areas of El Paso county over the next couple of hours but this development should stay subsevere. However, can`t rule out a stronger storm producing small hail up to one half inch and wind gusts up to around 50 mph. Once again, concerns are increasing for more organized development around Pueblo and to the east over the plains later this evening and tonight. While conditions aren`t appearing to come together right at this moment, latest trends and guidance are indicating this will change by mid evening. The mid level energy noted on latest WV imagery ejecting out ahead of a low amplitude mid/upper trough is expected to arrive over the next couple of hours. The arrival of this mid/upper forcing will help support lee troughing and a developing 700mb low across the eastern plains, with increases in 700mb and 850mb WAA as well as even some FGEN. The arrival of all of this increasing large scale ascent will of course support quickly developing thunderstorms but also support the erosion of the warm temps aloft. Instability develops across the plains as well as advects overhead this evening, while the resultant easterly flow supports strong and deep moist advection. So, expect additional thunderstorms to develop in the 8-10 pm time frame over the Pueblo county area and quite possibly southern El Paso county. During this time, developing MCS to the north is expected to dive south/southeast into the better instability with latest trends suggesting all of this merging into a larger complex of storms over the eastern plains/Highway 50 corridor late this evening into the overnight hours. Large hail to one inch is possible, though the previously mentioned warmer temps aloft may continue to help limit the extent of any hail tonight. A higher threat may be be damaging wind gusts possibly in the 60-70 mph range. However, even with this threat, there is still some uncertainty based on factors such as how long the overlap of forcing and instability will be and the time of night - likely increasing CIN. Additionally, surface trough axis and possible upstream outflow boundary could serve to increase the tornado threat later this evening, and will continue to closely monitor trends for this possibility. Lastly, the previously mentioned moist advection will likely bring mid to upper 60s surface dewpoints into eastern Colorado with short term guidance showing 850mb dewpoints of around 20c approaching the CO/KS border tonight. This increased moisture along with storm mode (east to west multicell and possibly training) will support an increased risk for heavy rainfall and flash flooding. One last item to note, is that this threat of severe storms and flash flooding could extend well into the overnight hours for areas over far eastern CO. && .SHORT TERM...(This evening through Saturday) Issued at 240 PM MDT Fri Sep 3 2021 Main Points: 1) Showers and thunderstorms are expected to increase in coverage later this afternoon and well into the overnight hours. 2) The Palmer Divide area will be seeing storms pass through, with gusty winds, locally heavy rainfall and small hail as potential threats. These storms should pop up in the next few hours and last until around midnight. 3) Strong to severe storms will be possible later this evening and tonight over the eastern plains, with the main threats being gusty winds, hail of 1-2 inches, and perhaps even an isolated tornado. Currently... Cloud cover over the CWA has broken up slightly compared to this morning, allowing for increased heating at the surface. A few showers have already popped up over both the Continental Divide and the far southeast plains, with no impactful weather reported as of yet. Just north of our area, past the Palmer Divide, several strong thunderstorms have already formed near the Denver Convergence Zone, with storm motion vaguely heading northeast. Today-Tomorrow... The tip of an upper-level trough is currently making its way eastward across Colorado, carrying with it enhanced lift and the majority of the forcing for enhanced precipitation. Showers have largely dwindled over the mountains and activity has steadily moved east throughout the day, although coverage is expected to increase overall as we progress later into the afternoon-evening hours, thanks to a healthy influx of mid-level moisture expected to circulate in around the upper-level high to our southeast. A weak surface boundary is also set up far to the southeast, intersecting portions of our southeast plains, which is assisting in giving us some easterly upslope flow over the plains. The slowly recovering, semi-stable air present in that area will also delay the onset of significant convection for a few hours yet at least, but once heating is able to overcome it and increase instability it may result in stronger storms this evening. Several short-term models have been consistently overmixing the boundary layer over our area, mixing out dewpoints by several degrees and limiting the extent of convection expected in our area. Given current moisture profiles over the plains, these models (including the HRRR) will have a bit less weight in the forecast for today and tonight, while the NAM seems to be handling things much better. Current analysis shows 500-1000 J/kg of CAPE over the Palmer Divide area, and between 1000-1500 over the far southeast plains. Around 30 knots of effective bulk shear are also present over the Palmer, with a considerable 45+ knots over the plains. Current dewpoints over the southeast plains are also currently sitting around the mid-60s. As of now, the main factor inhibiting thunderstorm development over the plains is the semi-stable air (and related CIN) sitting in that area. As daytime heating works to overcome it and continuously destabilize the environment, the main forcing will come later this evening as the axis of the upper trough passes overhead. As it does, that forcing is expected to spark thunderstorms along and near the boundary, assisted by easterly upslope flow increasing low-level convergence. With the CAPE and shear in place, as well as the ample moisture available in that area, we can expect a drastic increase in precipitation over the next 12 hours. To start, mostly moist, westerly flow aloft will assist in increasing shower coverage over the mountains later this afternoon, mainly over the San Juans, Sangres, and Continental Divide. As the trough axis moves more to the east, the main forcing will expand to cover the I-25 corridor, where upslope into our eastern mountains and the Palmer Divide will assist in sparking scattered to widespread showers and thunderstorms. As better forcing moves east and the plains become further destabilized, strong to severe thunderstorms will become possible later this evening into tonight. Given the available surface vorticity traveling along with the upper- level features, as well as the notable amounts of CAPE and shear available, gusty 60 mph winds and 1-2 inch hail will be well within the realms of possibility. Additionally, should an updraft manage to latch itself to the existing surface vorticity and maintain itself, cannot rule out the threat of an isolated tornado. Given the strength of the easterly winds expected over the plains, this threat could extend back to near the I-25 corridor, but is mainly confined to the southeast plains near the CO-KS border. Later tonight, storms are expected to continue, and as the upper trough moves east, storms are expected to move off of the Palmer and head southeast, where several short term models are actually resolving a larger system with potential QLCS properties moving across parts of the eastern plains before moving into Kansas by tomorrow morning. Showers are expected to persist into Saturday morning, although they should be more stratiform in nature. A cold front is expected to push south across the plains by late morning. Recent model trends have been consistent in keeping the front more robust, meaning that it will likely keep precipitation widespread over parts of the southeast plains and our southeast mountains. However, given the cooler, more stable air behind the front, thunderstorms, should any manage to form, will likely be much weaker than the storms we expect to see this evening. With post-frontal upslope flow expected to set in by early afternoon, main concerns for Saturday`s weather will be storms firing over and near the Spring Burn Scar, with flash- flooding concerns on the table should a more convective storm manage to drop consistent rain. Otherwise, things tomorrow will be more stratiform, with overcast skies over much of the plains and cooler .LONG TERM...(Saturday night through Friday) Issued at 240 PM MDT Fri Sep 3 2021 Overall, there is great agreement through the extended between the operational solutions and ensembles. This leads to higher confidence in the extended period. Saturday upper level trough is forecast to slowly move east into the Missouri Valley Saturday night, with trailing energy shifting south across Eastern Colorado. Moist, easterly upslope flow will be ongoing, with widespread precipitation from the Eastern Mountains, east along the New Mexico border. Weak instability may lead to a few thunderstorms over southern Sangre de Cristo and Raton Mesa areas. Locally heavy rainfall may be possible with stronger cores, which could produce a low risk of flash flooding on the Spring burn scar. This activity will shift south and east overnight, clearing to the southeast Sunday morning. Sunday through Thursday...high pressure will build over the Great Basin and slowly shift eastward during this period. This will keep dry conditions across southern Colorado for the Sunday afternoon, through Thursday time frame. A dry cold front will bring a continued cooler air mass to the area, with upper 80s to lower 90s across the Plains. Temperatures will gradually warm up by Thursday, with mid to upper 90s expected across the Plains. Friday...the upper level high will shift east into the Central Plains by Friday, with southwesterly flow returning to souther Colorado. Embedded energy could bring back showers and thunderstorms to the forecast along the Mountains. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 240 PM MDT Fri Sep 3 2021 KALS: VFR conditions expected over the next 24 hours. Winds will become gusty later this afternoon to about 20 mph before weakening again this evening. KCOS: VFR conditions generally expected through the next 24 hours. Isolated to scattered showers and thunderstorms are expected in the area, beginning after about 01Z and lasting through about 06Z tonight. Given the nature of the expected precipitation, it is still unclear whether anything will move directly over the terminal. If it does, expect brief periods of moderate to heavy rainfall and gusty erratic outflow winds. Will continue to closely monitor the area this afternoon and evening. Precipitation should move away from the area after midnight. After about 08Z tonight, there is a chance of some lower clouds developing over the terminal, but left with VFR conditions for now. KPUB: VFR conditions are expected over the next 24 hours. Isolated to scattered showers and thunderstorms will begin in the area around 23Z and increase in coverage throughout the evening and into the overnight hours. Direct impacts to the terminal are still expected to be low at this time, so left as VCSH. If a shower does manage to move over the terminal, brief periods of moderate to heavy rainfall and gusty erratic winds could be expected along with brief vis drops to MVFR. Rain is expected to clear out after about 09Z, where clouds will disperse and winds will weaken into tomorrow morning. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE...RODRIGUEZ SHORT TERM...GARBEROGLIO LONG TERM...MOZLEY AVIATION...GARBEROGLIO