Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/26/22

National Weather Service Bismarck ND
950 PM CDT Tue Oct 25 2022 .UPDATE... Issued at 950 PM CDT Tue Oct 25 2022 Updates were made to the cloud cover again to match with current satellite trends. The possibility of fog still exists in the northwest, both the RAP and HRRR have high RH after 06z. UPDATE Issued at 640 PM CDT Tue Oct 25 2022 Just some minor updates to the cloud cover based on the current satellite trends. The RAP is still showing the possibility of fog in the northwest with RH near 100 percent around midnight. && .SHORT TERM...(This Evening through Wednesday) Issued at 138 PM CDT Tue Oct 25 2022 The main forecast issue in the short term period will be sky cover and temperatures tonight. Currently, weak high pressure is situated over the forecast area. An exiting shortwave that brought some light snow to the northern tier counties this morning is exiting the area. Additional light reflectivities capable of producing a sprinkle or flurry were located over southeast Saskatchewan into southern Manitoba. This could rotate into northern ND late this afternoon or this evening and produce a brief sprinkle/flurry but only trace amounts are expected with no impacts. Warm advection will overspread the CWA from west to east tonight with a few bands of clouds expected to linger across mainly northern ND, but at times may extend into central or even southern ND. The warm advection and clouds would indicate mild overnight lows (relatively speaking) but with our recent snow there remains a pretty sizable area of snowcover over western ND, with the deepest snowpack from around the Interstate and northward. With high pressure over the area, expect winds to diminish this evening and think we could see temperatures drop pretty quick over the snowpack. However, to complicate things, some lower stratus and fog remains over portions of the snowpack. Thus at this time it seems fruitless to try and guess temperatures here. We did go ahead and blend the cooler previous guidance with our given NBM guidance to lean a bit toward cooler temperatures over the snowpack. Expect the evening and overnight shifts will need to revisit at least a few times. We also kept a mention of patchy fog over and around the snowpack. The RAP is indicating fog developing in the northwest later this evening, but on occasion is a little overdone. The HRRR is depicting very little fog here at this time. Wednesday looks to bring a mix of sun and clouds with slightly warmer temperatures most areas. .LONG TERM...(Wednesday Night through Tuesday) Issued at 138 PM CDT Tue Oct 25 2022 Generally a quiet extended period looks to be in store, with a quasi- zonal flow over the northern tier states through the weekend. Early in the period the upper flow splits over the northern and central Rockies, with most energy sliding well to our south. However, a bit of energy remains in the northern stream and we may see a bit of light precipitation brush our southeast CWA Wednesday night into Thursday morning. Thereafter, impulses will be coming off the Pacific and across the Northern Rockies with little moisture reaching the Northern Plains. We could see some increasing high clouds later in the extended period but after the Wednesday night/Thursday system, our NBM PoP forecast is dry through the weekend and into early next week. NBM Ensemble spreads later this week and through the weekend remain fairly narrow indicating good confidence in the given ranges. Normals for late October are in the lower 50s for highs and mid to upper 20s for lows. For the most part, it looks like we should be around normal to a little above normal through the extended period for both highs and lows. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) Issued at 950 PM CDT Tue Oct 25 2022 MVFR clouds remain across the east, affecting KJMS, these will move out by 09z. Lower clouds between 3-10 kft will remain through Wednesday morning for the rest of the area. The clouds will mostly clear out by early morning with VFR conditions through the period. Patchy fog is possible in the northwest, affect KXWA, was not confident enough to put lower visibilities in the TAFs yet. Timing could be around 06z. Winds will be light overnight then gusting up to 15kts from the south Wednesday afternoon. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Smith SHORT TERM...TWH LONG TERM...TWH AVIATION...Smith
Area Forecast Discussion
National Weather Service Birmingham AL
748 PM CDT Tue Oct 25 2022 ...New SHORT TERM, AVIATION... .SHORT TERM... (Tonight through Wednesday) Issued at 720 PM CDT TUE OCT 25 2022 A cold front was located just southeast of the I-59 corridor this evening. The front will continue eastward and clear the area after midnight. Showers and a few thunderstorms were ongoing ahead of the front from near Anniston to Montgomery. Shear remains high over the area but instabilities were limited and lapse rates were poor. Do not expect any uptick in this activity as it exits the area after midnight. Gusty Winds will slowly subside through the evening. The chances of any gusts near 35 mph is rather low and will cancel whats left of the Wind Advisory. 75 Previous short-term discussion: (This evening through Wednesday) Issued at 141 PM CDT TUE OCT 25 2022 A potent upper low was located over the Ozarks in Northern Arkansas within a negative tilted trough over the Mid South Region. Surface low pressure has become more organized over Southeast Missouri with a cold front extending from Southwest of St. Louis south through Central Mississippi. Regional radar composites with satellite animations indicate the convection has been strengthening gradually with time over the past few hours as the activity is moving east through an area with temperatures in the lower 70s with dew points in the upper 60s. Surface-based instability persists in a fairly narrow swath along and just ahead of the convective line from eastern Mississippi to near the AL/MS state line per 17z RAP mesoanalysis data. The highest shear and best forcing is positioned across Northeast Mississippi and Northwest Alabama at this writing. Through mid afternoon, expect the line of storms to continue moving east into West-Central and Northwest Alabama from 1 to 3 pm. A tornado watch is currently being issued for the western portion of the area, generally near Interstate 65 and west through 7 pm tonight. Tonight. Showers with some thunderstorms will continue to move east, affecting much of the eastern portion of the area tonight. The overall intensity of the line is expected to gradually weaken with time with damaging winds being the primary concern with bows within the line of storms. There will remain a tornado risk with embedded circulations, QLCS, within the line of storms. Winds will gradually weaken overnight from the southwest to west at 6-12 mph. Lows will range from the mid 40s northwest to the low 50s southeast. Wednesday. Dry conditions will return areawide on Wednesday but cloud cover will likely linger through the morning hours then clearing entirely from southwest to northeast through the daytime hours. Winds will be from the west to northwest at 6-12 mph. Highs will range from the mid 60s north to around 70 far southeast. 05 && .LONG TERM... ((Wednesday night through next Monday) Issued at 318 PM CDT TUE OCT 25 2022 Models have trended slightly wetter for the system next weekend, and trended rain changes and qpf upward. Otherwise, no changes needed. 14 Previous long-term discussion: (Wednesday night through Monday) Issued at 308 AM CDT TUE OCT 25 2022 Flow aloft becomes southwesterly through the rest of the week ahead of the next trough digging into the Southern High Plains in this progressive split flow pattern. At the surface, winds will be out of the east courtesy of a strong high pressure center centered over Quebec, though the associated CAD wedge should stay northeast of the area. The easterly winds will keep dew points and RH values from crashing as much as in recent days as well as low temperatures to a certain extent. Expect pleasant conditions with a good bit of sunshine. The southern stream trough will eventually close off into a slow- moving upper low that will impact the forecast area over the weekend. Deep layer SSW flow ahead of the upper low will eventually result in moist isentropic lift and widespread rainfall at some point during the weekend, while a weak surface low lifts northward over the Lower Mississippi Valley. The deterministic GFS trended slower towards the deterministic ECMWF with the area remaining mostly dry Saturday afternoon. However, am leery of buying this trend as these are just 2 of 80 ensemble members, and the ensemble means and many ensemble members of the EPS and GEFS are quicker than the deterministic runs. Therefore, leaned heavily on the ensemble members for timing of the higher PoPs but have capped values at 50% for now. A warm front may lift northward into our southern counties with enough instability for a few thunderstorms. 0-6 km bulk shear values are only around 30-35 kts, so severe storms are not expected at this time. 32/Davis && .AVIATION... (00Z TAFS) Issued at 720 PM CDT TUE OCT 25 2022 A cold front was moving through Central Alabama as of this writing. It was approaching BHM/EET as winds have turned to the west at TCL. Showers and a few thunderstorms were ahead of the front from near ANB to MGM. The convection will affect ANB/ASN/MGM/TOI for another hour or so before exiting the area. There may be a brief period of MVFR ceilings near this convection. A wrap around moisture area will follow behind the front and also may produce some MVFR ceilings for the northern sites. Gusty southerly winds will veer to west and then north as high pressure moves in behind the front. 75 && .FIRE WEATHER... Drier conditions return for Wednesday and Thursday, but with minimum RH values above critical thresholds. Low level winds swing around to the north Wednesday and northeast Thursday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 45 64 42 72 / 90 0 0 0 Anniston 47 64 44 73 / 90 0 0 0 Birmingham 47 64 46 72 / 50 0 0 0 Tuscaloosa 46 68 46 72 / 10 0 0 0 Calera 46 65 47 73 / 50 0 0 0 Auburn 49 67 47 73 / 90 0 0 0 Montgomery 48 69 45 75 / 80 0 0 0 Troy 50 69 45 76 / 90 0 0 0 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...75 LONG TERM....14 AVIATION...75
Area Forecast Discussion
National Weather Service Denver/Boulder CO
901 PM MDT Tue Oct 25 2022 .UPDATE... Issued at 900 PM MDT Tue Oct 25 2022 There is a little disturbance approaching in the mostly westerly flow aloft and the next shortwave isn`t far behind that, coming on shore over the Pacific Northwest. Skies are mostly cloudy to overcast across most of northeast Colorado. There are some light snow showers around the peaks of the Front Range which will persist through the night. Radar suggests there may be a few very light rain showers on the eastern plains as well, but it`s harder to say. The forecast is performing well with only minor updates this evening. && .SHORT TERM...(This evening through Wednesday) Issued at 254 PM MDT Tue Oct 25 2022 Satellite and RAP mesoanalysis show that... not a whole lot has changed since the morning AFD. Colorado remains underneath westerly flow aloft, with moisture increasing slightly over the past several hours. As a result, there`s been a slight uptick in snow showers across the northern mountains, particularly the Park and Medicine Bow Ranges, where webcams and SNOTEL data have suggested at least some light accumulations have already occurred. Snow is expected to continue across the higher terrain overnight, gradually shifting south this evening. There should be a slight increase in coverage and intensity towards daybreak Wednesday as QG ascent increases, with a couple inches of snow expected. A cold front will also push across the plains overnight, with mid-level frontogenesis (and its accompanying lift) along with some weak upslope flow might be enough for a few rain and snow showers over the plains, though temperatures will likely be too warm to support any accumulation below 7000 feet. Wednesday will see snow showers continuing across the mountains. The flow aloft will shift more to the west-southwest ahead of an approaching trough, so most of the snow should be focused on the Park and Gore ranges early in the day. Across the plains, a few light showers may continue along the Wyoming border, but otherwise it should be mostly quiet. Precipitation should increase across the mountains yet again by late Wednesday afternoon as PVA associated with the approaching shortwave should lead to a brief period of enhanced rates. For more details on the snow Wednesday night into Thursday keep reading the section below... .LONG TERM...(Wednesday night through Tuesday) Issued at 254 PM MDT Tue Oct 25 2022 There`s reasonable agreement on the trough moving across Colorado Wednesday night into Thursday. Minor differences on QPF and temperature do affect snow prospects for Denver, as most of the models are struggling to get cold enough while most ECMWF ensemble members do produce an inch of snow. It`s only a degree or two so it`s hard to pick a winner at this point. With the QG lift sliding southeast from the northern mountains and the surge of upslope, this could be a scenario where there`s a definite focus of precipitation sliding south along the foothills from Boulder to Douglas county with much less elsewhere. We`ve generally accepted the NBM QPF but raised PoPs and bumped up the snow ratio a bit for a bit more snow in the mountains and a little accumulation where it does snow along the foothills. The lift moves out and drier air, subsidence, and warming aloft come in quick behind it later Thursday. This should set up a cooler night for Denver and Boulder with a more definite freeze for most spots Friday morning. Temperatures should pop back up to near 60 in Denver for Friday through Sunday, with valley areas lagging a little in cold pools for at least the first day. A shortwave passing north of us Sunday could bring some clouds, then we go to a bit more flow from the west or southwest for early next week that should provide some wind in the wind prone areas. Faster solutions would bring some moisture in the southwest flow by Tuesday, but probably not enough for mountain snow yet. There could be a couple of marginal fire weather days in the early to middle part of next week ahead of the next trough when it looks dry, warm, and breezy. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 533 PM MDT Tue Oct 25 2022 Expect VFR conditions to persist through the rest of today, then ceilings to lower this evening and overnight with potential for ILS ceilings at about 4 to 6 kft into the morning. There is a slight chance of very light rain or snow showers tonight but confidence is low and impact would be minimal. Ceilings should rise in the morning. Winds have come around north-northeasterly at KDEN and KAPA this afternoon, while breezy westerly winds persist at KBJC and and look to continue into the evening. Winds should come around southeasterly tonight and in the morning, then turn back northeasterly for the afternoon. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...EJD SHORT TERM...Hiris LONG TERM...Gimmestad AVIATION...EJD
Area Forecast Discussion
National Weather Service Columbia SC
724 PM EDT Tue Oct 25 2022 .SYNOPSIS... A front will cross into the region late tonight, with scattered showers possible towards morning. Dry weather is expected behind the front through Friday. Chances of rain increase late in the weekend when another upper disturbance approaches from the west. && .NEAR TERM /THROUGH TONIGHT/... The upper level cutoff low centered over southeastern Missouri will continue lifting off to the northeast overnight. The trough axis south of the cutoff will help to push a prefrontal trough into our region late tonight. Moisture increases ahead of this surface trough after midnight, helping to push some showers towards the cwa. Best dynamics remain well north, and mainly expecting a line of scattered showers with an isolated thunderstorm possible. QPF amounts still look to remain light. The best timing for the line entering the western cwa still appears to be centered around 09z, with the bulk of the weakening activity then exiting off to the east by 12z. With an increase in clouds cover and winds later tonight, temperatures will drop into the lower to mid 50s. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Closed upper low will track NE along the Ohio Valley and open and shift into New England/E CAN Wednesday, with most upper dynamics staying to our north. Latest CAMs in good agreement that weak surface front and associated scattered light shower activity will move into the CSRA by daybreak, through the central forecast area (FA) during the morning to midday hours, and push east of our FA during the afternoon, while the shower activity is expected to gradually diminish. Weak upper ridging to shift back into the region Thursday. The air mass behind the weak front is not cool with a surface high center emerging from N Mex/TX and shifting NE and merging with a Canadian high center to the north. The main upper flow will keep the coolest air well to our north. Drier air will be shifting into the region behind the boundary with PW generally averaging around 0.75 inch Thu. Expect winds to veer behind the surface boundary passage late Wed/Wed nt, and become NE by Thu. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Upper low to cut off over the S Rockies/West TX and shift east to the Lower Miss Valley Fri/Sat with resultant surface low developing near the TX/LA coast. Main zonal upper flow across the northern tier of states/S CAN. Confluent flow aloft to intensify the surface high center to our NE as it shifts east across E CAN and settles over New England. The closed low is progged to open and shift NE into the Midwest Sun/Mon along with the surface low, followed by upper energy expected to track from the SW US east across TX Monday and towards our region Tuesday. Meanwhile, the surface high will ridge down the eastern seaboard. Latest information indicates best isentropic lift/moisture transport for our region will be Sat nt/Sun/Sun nt, with hybrid cold air damming regime setting up at the surface. Due to the wedge, max temps are expected to trend down considerably for Sun/Mon. The wedge and associated low clouds and cool max temps are expected to be slow to erode with only weak surface high pressure, and SW flow aloft, over the region Mon/Tue. It appears good downslope flow to scour out the low cloudiness does not occur until late Tue/Tue nt into Wed behind the passage of an upper disturbance. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... High confidence in VFR conditions through 06z or so then possible MVFR ceiling restrictions Wednesday morning. Upper system and associated cold front to our west will push eastward tonight and cross the region on Wednesday morning. Winds have been calm to light and variable and will remain so through the evening. After midnight the pressure gradient will increase a bit and southerly winds should develop less than 5 knots ahead of the prefrontal trough. Clouds will also be increasing and lowering through the predawn hours. The latest HRRR and NBM suggesting fog development in the coastal plain after 06z. The probability of visibility restrictions at the area terminals should remain quite low as mid level clouds increase along with increased winds in the boundary layer. A broken line of showers is expected to push across the region during the 11z-16z time frame. Some MVFR cigs may accompany this feature along with some isolated showers. Behind the trough, winds will pick up from the west-southwest and become gusty into the afternoon. Showers not expected to lead to visibility restrictions. EXTENDED AVIATION OUTLOOK...No significant impacts to aviation expected through Thursday but chances for restrictions with low clouds could increase starting Thursday night into Friday and impact the weekend. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Lincoln IL
844 PM CDT Tue Oct 25 2022 .SYNOPSIS... Issued at 308 PM CDT Tue Oct 25 2022 Additional rounds of scattered showers and isolated thunderstorms are expected to continue through Tuesday night as a low pressure system moves through the region. Breezy northwesterly winds are expected tonight. The breezy winds continue on Wednesday, with clearing skies and temperatures in the upper 50s. Thursday and Friday look seasonable, with lighter winds and high temperatures in the mid 50s to near 60. After tonight, the next chance of rainfall is late Saturday night into Sunday. && .UPDATE... Issued at 838 PM CDT Tue Oct 25 2022 As of around 8pm this evening, surface low pressure was analyzed to be centered near Mattoon. Scattered showers are ongoing across much of the area, but most numerous near the Illinois River Valley where a deformation axis is in place. An additional quarter to three quarters of an inch of rain is likely overnight near the Illinois River Valley with a quarter inch or less expected elsewhere. Forcing within this feature will shift northeast through the evening and tonight with precip ending from the southwest overnight, but not completely exiting the forecast area until around daybreak Wednesday morning. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 308 PM CDT Tue Oct 25 2022 Satellite imagery shows a low pressures system continuing to lift northeast through the Ozarks. The front across our area continues to shift slightly east, located between I-55 and I-57 as of 2pm/19z. Widespread rain continues across the CWA, as the warm conveyor belt of the approaching low pressure system pivots through the area. RAP mesoanalysis shows low but non-zero MUCAPE across eastern IL, where a few embedded t-storms are ongoing/will be possible this afternoon with the warm conveyor belt precip. A precip free corridor appears likely to pivot through the area this afternoon/evening, then additional rain chances occur as the low moves northeast through the area tonight. Ahead of the sfc low, clearer skies have allowed a small zone of surface-based instability to develop over southern MO, and t-storms have erupted within that zone over the last hour (to the south of Farmington, MO). This zone will pivot through the southeastern half of our CWA this evening, but by the time it does so diurnal heating will be diminishing, so while t-storms may persist the chances of stronger storms is low. Another frontogenesis zone oriented north-south immediately behind the low is producing another band of rainfall that will move west to east through the area overnight, bringing precip chances to an end as it departs before sunrise on Wednesday. Additional rainfall amounts from the precip that occurs as the low pressure moves through the area tonight will generally be around 0.25-0.50", although locally higher amounts are possible with any t-storms. With the low lifting off to the northeast on Wednesday and sfc high pressure centered over MO/IA, brisk northerly winds will keep a chill in the air for much of the day as temps only reach the upper 50s. As the sfc high shifts east towards the area, winds gradually become lighter into the afternoon. Aside from some lingering cloud cover in eastern IL Wed AM, mostly sunny skies will prevail. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 308 PM CDT Tue Oct 25 2022 For the start of the long term period, a few benign, seasonable days are expected. By Wed night, sfc high pressure should be positioned just north of the area, and the combination of clear skies/light winds will result in the coolest night of the week, with lows dropping into the upper 30s. That high pressure quickly shifts off towards the Great Lakes on Thurs and strengthens as it does. Thurs and Fri both look seasonable, with highs in the mid 50s to near 60F, and lows near 40. Forecast soundings suggest rather widespread high cloud cover on Thurs, becoming less extensive on Fri. The next chance of rain will be courtesy of a closed upper low moving slowly through the southern Plains Fri into the weekend. Model guidance remains inconsistent in the precip timing with this wave. Precip could move in as early as late Sat eve, but the chances increase into Sun and diminish into Monday. Based on the track of the wave, precip chances decrease from southeast to northwest across the CWA. QPF amounts aren`t expected to be as heavy with this wave, with the latest probabilistic data from the NBM showing a 35% chance of exceeding 0.25" and less than a 5% chance of exceeding 1". Despite this wave passing through the region, no major temperature changes are expected through the extended forecast. Highs will generally be in the upper 50s to mid 60s with lows in the low 40s. An early look at Halloween night suggests temperatures near 50F and minimal impacts from wind or precip, although if the upper wave trends slower some light precip could linger into Halloween night. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 620 PM CDT Tue Oct 25 2022 Low pressure is near Effingham this hour and will lift northeast across east central Illinois this evening. Scattered showers and an isolated storm or two will continue through the rest of the evening across central Illinois, then will taper off from the west overnight. Meanwhile, gusty north to northwest winds will set up behind the low but gusts are expected to diminish overnight into Wednesday morning. IFR/MVFR ceilings will also accompany the low and will also improve back to VFR late tonight into Wednesday morning. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Deubelbeiss SYNOPSIS...Erwin SHORT TERM...Erwin LONG TERM...Erwin AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service Pocatello ID
857 PM MDT Tue Oct 25 2022 .UPDATE... Updated forecast to lower overnight lows as temps have fallen quickly this evening under clear skies. Expect clouds to arrive overnight which should help insulate. Temps are a little closer to the NBM forecast based on evening trends and timing the cloud cover. 13 && .PREV DISCUSSION... /issued 238 PM MDT Tue Oct 25 2022/ SHORT TERM...Today through Wednesday. We`ll stay mostly dry through the rest of today aside from some light precipitation lingering in the eastern highlands with breezy conditions through the Magic valley and Snake plain with gusts up to about 30mph until 8-9PM. Our next system starts to move in around midnight as snow begins in the Sawtooths and spreads south and eastward through the central mountains and across the rest of the state during the early morning hours. Models are hinting at the potential for a band of a rain/snow mix during the morning moving from west to east which could impact parts of I-86 and I-15 from 7- 10AM. Temperatures will be hanging right around freezing or just above, which could limit snow and give more rain south of Blackfoot. Temperatures will be a couple of degrees cooler north of Blackfoot, which would lend themselves towards snow more than rain. Winds are going to be breezy at the time, but are expected to pick up post-front, which would help limit snow squall potential, but it is still worth watching and keeping in mind for the morning commute. While the ingredients are there, the uncertainty lies with whether or not they all come together at the right time. The NAM and HRRR bring in another band of snow after 4PM that will impact areas of the Snake Plain and eastern highlands, staying mainly north and east of the Pocatello area, though the HRRR wants to skirt the eastern edge of Pocatello. Most of the snow, aside from some light showers in the higher elevations of the eastern highlands comes to an end shortly after midnight. The highest snow totals will generally be 4-6 inches in the Sawtooths, Big Holes, and Bear River Range with the rest of the mountains seeing 2-4 inches. Snow totals in the Snake Plain and Magic Valley will be below an inch with the NBM 4.1 WSUP viewer showing only a 15-25 percent chance of an inch of snow. The wind is also going to be a player in the forecast. Went with gusts from the 90th percentile of NBM 4.1 and still had to bump them up slightly and am getting gusts between 30-35mph and sustained winds between 25- 30mph which is just below wind advisory criteria. That said, some localized areas within the south hills and Magic Valley have a 30-40 percent chance of seeing isolated gusts closer to 40-45mph. Winds will be strongest between noon and 8PM on Wednesday before they begin to back off. Our weather begins to quiet down as we head into Thursday morning. AMM LONG TERM...Thursday through Tuesday. Upper ridge builds into the region behind departing shortwave Wednesday. Temperatures remain cold, but slowly moderate Friday into Saturday. Next Pacific trough slides south along Alaskan/BC coast by Saturday, with weak shortwave flattening ridge ahead of it by late Saturday. From there, solutions begin to deviate so there is still quite a bit of uncertainty through remainder of the period. Most solutions favor precipitation onset by Sunday afternoon across the central mountains, but slow to spread east. Ensemble clusters still show quite a split between a very shallow ridge and a flat trough across the region Sunday, but nearly all give way to the Pacific trough moving into the PacNW or across the Northern Rockies by Monday. NBM has trended slower as well, holding off on bulk of precipitation until Monday/Tuesday. From there, solutions remain consistent with valley rain/snow, mountain snow, and breezy to windy conditions. DMH AVIATION...Weak late fall afternoon shallow convection still lingers across the eastern highlands impacting KDIJ this afternoon, but remainder of terminals remain VFR. Next system drops into the region late this evening, spreading light precipitation west to east through Wednesday morning associated with frontal boundary. Ceilings drop fairly rapidly with precipitation onset, and could temporarily drop to IFR/LIFR with any convective enhancement of bands associated with front. Precipitation should be all snow at KSUN/KDIJ, mixed at KIDA, potential mix at KPIH, and all rain at KBYI. Gusty winds associated with the front, and then in post-frontal environment Wednesday afternoon, could gust well over 30kts. DMH && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Pueblo CO
251 PM MDT Tue Oct 25 2022 .SHORT TERM...(This evening through Wednesday) Issued at 250 PM MDT Tue Oct 25 2022 Key Messages: 1) Slightly cooler for our Wednesday with snow beginning in the mountains and breezy winds elsewhere. Currently.. Satellite imagery depicts fairly zonal flow, with increasing cloud cover coming in from our northwest, and widespread mountain wave cloud formations over Colorado as well. Temperatures have warmed into the low to mid 60s for most of the plains, and winds are following normal diurnal patterns in most areas. A trough is deepening over the Pacific Northwest. Tonight and Tomorrow.. An upper trough pushing across the northern plains drops a weak cold frontal boundary across eastern Colorado overnight. This feature doesn`t look to bring too many changes, but we could see some briefly breezy northerly winds as it passes, particularly north of Highway 50. Daytime high temperatures will be a couple of degrees cooler tomorrow as well, with most of the plains warming into the 60s, mountain valleys getting into the 50s, and higher terrain locations staying in the 40s. Upslope flow sets up over our central mountains, where snow showers are expected to begin as early as 9pm this evening. As the Pacific Northwest trough and associated low pressure system push into the Northern Rockies tomorrow, our flow aloft will turn from mostly zonal to southwesterly throughout the day. This will bring continued orographic upslope flow and plenty of moisture to our central mountains, where light to moderate snowfall is expected throughout the day. Snow is forecast to spread southeastward, into the La Garitas and San Juans by early morning and possibly even into the western facing slopes of the Wet Mountains by early afternoon as well. As the system plunges southward into the four corners region by tomorrow afternoon, the pressure gradient will tighten overhead. This will bring gusty southwesterly winds to the San Luis Valley and breezy southerly winds to our eastern plains as well. Relative humidity values behind tonight`s frontal boundary keep us too moist to warrant fire weather headlines at this time, but winds could gust up to 30 mph tomorrow afternoon. .LONG TERM...(Wednesday night through Tuesday) Issued at 250 PM MDT Tue Oct 25 2022 Key messages: 1) A deepening major shortwave trough is going to impact the region with snow (mainly over mountains), windy conditions, and colder temperatures Wednesday night through Friday morning. 2) Ridge will build in with a warning trend and drier conditions throughout the weekend and into early next week. Detailed discussion: Wednesday night through Friday... Deterministic models are in relatively close agreement of a deepening of a major shortwave trough with a positively tilted axis propagating in over the region by late Wednesday night though Thursday. The position of the associated closed low at the 500 mb level is generally close, with the exception of the Canadian model, with being over the southeastern portion of Idaho. The Canadian is the outlier with having the position being over the western portion of Wyoming. This keeps the progression slightly ahead of the other models and allows for a better chance of precip over the plains if this verifies. Otherwise, the progression has only slight deviation between the models with the low moving nearly over the Four Corners area as the shortwave continues to deepen. This will result in the mountains getting most of the precip with this storm system, as the U/L divergence is centered over the Continental Divide area. The cold front associated with this system looks to move over the CWA around between 3 and 6 AM during the morning on Thursday. The high resolution models such as the HRRR has the front arriving as early as 2 AM over the most northern portion of El Paso County. There could be some snow showers with accumulating snow of possibly an inch or more over the Palmer Divide and northern I-25 corridor in El Paso County as it does, which may result in some tricky travel conditions during the morning commute for this area as it does. Due to upsloping as the winds become northeasterly, there could be some locally heavy snowfall amounts for the eastern facing slopes of the Wet Mountains and the Sangre de Cristo Mountains. With some upper level diffluence over the central mountains, there could be enough PVA to allow for sufficient instability and some thunder possible with the snow showers, especially over the Sawatch Range during the afternoon on Thursday. Northerly winds will continue to increase and become rather blustery throughout the day over the plains, especially over eastern El Paso County, where the winds could gust close to High Wind Warning criteria for a few hours. With snow showers likely over the Palmer Divide, this may produce occasional blowing snow with near white out conditions in this area. These winds will continue to come down by later in the evening as the gradient relaxes. As the U/L low continues to progress further to the southeast over central New Mexico, the mid level flow at the 700 mb level is going to turn to the northeast, with the strongest winds being reflected in the ECMWF. Given this, there could be some locally heavier snowfall amounts over the southern Sangre de Cristo Mountains by later in the day on Thursday. The colder air advection should keep temperatures mainly in the 40s over most of the plains, and perhaps only making it into the 50s over the far eastern plains. As a whole, temperatures will be anywhere between 10 to 20 degrees below the seasonal average across the CWA. Upsloping should keep most areas overcast along the I-25 corridor. The snow level will drop to as low as around 5300 feet over northern El Paso County. Some of the rain/snow showers will continue over the southeastern plains into the early morning hours on Friday due to wrap around moisture, although most of the CWA should clear out by then as the low pressure system continues to move out of the area. Due to sufficient radiational cooling because of this, there will be very cold temperatures on Thursday night through Friday morning, with some locations in the higher mountain valleys dropping into the single digits and perhaps even below zero. There will also be a slight chance of some freezing fog in some of the higher valleys and the San Luis Valley. Friday will be slightly warmer as surface winds out of the north weaken and switch back to a southeasterly direction by later in the day. Saturday through Tuesday... As a ridge continues to build back in over the region throughout the weekend, temperatures will return back to the seasonal average with drier conditions expected to last into early next week under high pressure. Looking past the forecast period into the later part of next week, there are some indications with ensemble data of the EPS and GEFS alike of the ridge breaking down and a longwave trough beginning to move in over the region and possibly influence the region with colder and unsettled weather. -Stewey && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 250 PM MDT Tue Oct 25 2022 VFR conditions are expected at all three terminals, KCOS, KPUB, and KALS for the next 24 hours. At KCOS and KPUB, a weak frontal boundary will increase northerly winds overnight tonight and help to increase mid-level cloud coverage as well, especially at KCOS. At KALS, winds will become northerly and eventually variable overnight tonight. A strong pressure gradient will increase southwesterly winds tomorrow in the San Luis Valley, bringing gusts over 20kt to the terminal tomorrow afternoon. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...EHR LONG TERM...STEWARD AVIATION...EHR