Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/15/22

Area Forecast Discussion
National Weather Service Cheyenne WY
951 PM MDT Wed Sep 14 2022 .SHORT TERM...(This evening through Thursday night) Issued at 255 PM MDT Wed Sep 14 2022 Latest surface analysis shows a surface low over western SD ahead of the upper level shortwave with a secondary surface low to the south near the CO/WY/NE border. GOES WV imagery shows ample moisture over the central Rockies through the northern Great Plains that previous shifts have noted is associated with the remnants of Kay. This moisture will be the main weather story for the short-term period as multiple shortwaves passing in the flow will help bring chances for scattered to widespread showers and thunderstorms late this afternoon and Thursday. So far this afternoon, weak convection has been tied to the higher terrain between Cheyenne and Laramie with additional storms in south-central WY approaching western Carbon Co. Hi-res guidance shows fairly widespread coverage with additional storms moving northeast out of northern CO. Weak 500mb flow will help keep shear values below severe thresholds, while latest RAP forecast only places 600 J/kg of MLCAPE over the Laramie Range. With the moist column, these are fairly long, skinny CAPE profiles. East of the Laramie Range, boundary layer moisture is much lower which could lead to gusty, erratic winds from these storms. With the upper level support, these storms will continue into the Nebraska Panhandle early this evening before mostly dissipating by midnight. A few lingering showers will be possible headed into Thursday morning. However, coverage will increase once again in the afternoon with another shortwave passage. Greatest coverage of storms looks to be along the I-80 corridor from Laramie to Kimball in the afternoon, but the latest HRRR. Kept the cooling trend that the NBM has had the last few days for Thursday as mostly cloudy skies are expected and 700mb temps drop near 5C before slowly warming back up headed into the weekend. Expecting afternoon highs in the 60s across SE WY Thursday while much of the Nebraska Panhandle will reach the 70s. .LONG TERM...(Friday through Wednesday) Issued at 255 PM MDT Wed Sep 14 2022 Long Range models in good agreement this weekend through early next week, with some disagreement on next week`s cool down around Wednesday and Wednesday night. For this Friday, all models show a third upper level disturbance embedded in southwest flow aloft moving across southeast Wyoming and western Nebraska. This feature will help initiate scattered showers and thunderstorms across the area, especially the eastern High Plains along/east of I-25 Friday afternoon. A few thunderstorms may become organized with gusty winds and locally heavy rainfall possible. Not terribly impressed with the available moisture nor low level instability, but there should be enough forcing that a few stronger storms can`t be ruled out. Otherwise, it will remain seasonable with highs around 70 west of I-25, and 75 to 85 degrees east of I-25 into western Nebraska. All models show the upper level ridge axis rebuilding over the Front Range and adjacent Great Plains states this weekend. Still a good chance for showers and thunderstorms Saturday afternoon, but coverage should be lower compared to Friday with most of the activity mainly up north. Another drying trend is expected Sunday and Monday with highs climbing back into the upper 70s to upper 80s for southeast Wyoming and into the low to mid 90s for western Nebraska. As we head into Tuesday and Wednesday, models are hinting at a well defined upper level trough pushing across the Great Basin region. The ECMWF shows a upper level closed low into Wednesday with much slower progression compared to the GFS and Canadian, but a higher chance at some decent precipitation across the region since we`ll be on the southeast flank of the low as it ejects northeast. The GFS and Canadian are colder and more breezy with 700mb temperatures dropping to -2c to -6c by Thursday. Trended temperatures cooler on Wednesday with good ensemble support, but only increased POP a small amount due to timing concerns. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 951 PM MDT Wed Sep 14 2022 A few lingering rain showers overnight for some western Nebraska terminals and KRWL. Showers may contain gusty winds and light to moderate rain, which could lead to brief visibility reductions. An incoming shortwave will lead to lowering CIGs at KRWL and KLAR during the morning hours on Thursday, leading to MVFR conditions. Scattered showers and thunderstorms are expected during the afternoon hours. && .FIRE WEATHER... Issued at 255 PM MDT Wed Sep 14 2022 Minimal fire weather concerns the next few days with scattered showers and thunderstorms possible through Saturday. In addition to the chance for precipitation, cooler weather near normal for mid-September will help keep afternoon RHs above critical thresholds. Fire weather concerns increase late this weekend into early next week as a quick warm up will lead to drier conditions across the area. Winds also look to reach critical thresholds, especially west of the Laramie Range over much of Carbon and Albany counties. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...MB LONG TERM...TJT AVIATION...SF FIRE WEATHER...MB
National Weather Service Sioux Falls SD
1031 PM CDT Wed Sep 14 2022 .SHORT TERM...(This Evening through Thursday) Issued at 245 PM CDT Wed Sep 14 2022 A hot afternoon has developed with temperatures in to near 90 degrees for areas along and west of the I-29 corridor. Dew points have remained high enough (upper 50s to lower 60s) to avoid critical fire danger levels, but burning should still be avoided if possible due to gusty winds at 25 to 35 mph. Satellite images early this afternoon show wildfire smoke streaming in aloft with a mid level wave moving through the NE Panhandle into south central SD. This wave, combined with diurnal cooling after sunset, is expected to induce a weakly unstable layer near/above 700mb later this evening. The 18z HRRR and 12z NAMNest guidance generally agree on scattered high based showers and isolated thunderstorms developing west of a Brookings to Tyndall line late this evening and overnight. Given inverted-V soundings present, very little rain (less than a tenth inch at any one site) is expected to reach the surface, but this activity could bring gusty erratic winds, occasionally mixing gusts up to 50 mph down to the sfc. Further east, expect mostly dry conditions with increased cloud cover and gusty winds generally in the 20s and occasionally 30s. Overnight warm air advection in response to the low level jet will keep nighttime low temperatures very warm, in the 60s to near 70 degrees. In fact, Mitchell and/or Huron SD will be within a few degrees of breaking a record warm low temperature. Expect a break in rain chances for the very early morning hours, but rain chances increase again after sunrise as another weak disturbance moves in via southwest flow aloft. Expect spotty showers and occasional thunderstorms starting in south central and southeast SD and increasing in coverage some through the day as activity spreads east, but only a few sites have a decent shot of seeing over a tenth inch of rain. The highest rainfall amounts are most likely along the SD/NE border where instability is a bit higher. Severe weather threat is very low with weak instability and unidirectional winds with modest mid to upper level flow. Overall expect a gusty south wind, cloudy conditions and a slightly milder day with highs mostly in the lower to mid 80s. .LONG TERM...(Thursday Night through Wednesday) Issued at 245 PM CDT Wed Sep 14 2022 Periods of off and on rain chances continue Thursday night through Saturday as upper ridging slides east and southwesterly flow aloft brings a parade of weak disturbances through the Central Plains. Euro/GFS ensemble and deterministic guidance suggest a swath of showers and perhaps a few thunderstorms developing Thursday afternoon and night across eastern SD and central to eastern NE as a shortwave overrides an approaching cold front. 12z NAM guidance is the drier outlier for Thursday evening, with a stronger afternoon preceding shortwave and slower evening wave. Still have lower than average confidence in timing and amounts, but a majority of guidance continues to support a high (60-90%) chance of 0.10" or greater for Thursday night, especially south of the I-90 corridor in SD/NE. By mid morning Friday, rain chances decrease behind the wave so should see a drier day than not. The approaching front stalls in the region Friday with cloudy skies and cooler air resulting in highs in the 70s to lower 80s, warmest south of the I-90 corridor. 12z guidance suggests the next shortwave initiates convection in the western Dakotas or Nebraska Friday evening, tracking into the region sometime Friday evening through early Saturday morning. Although there is lower confidence in the timing/track, an incoming mid level jet max also supports potential for severe wx so will need to monitor despite weaker instability being present. If the stalled front lingers in the region Saturday, instability will likely have amounted to enough (MUCAPE > 1500 J/kg ahead of the front) to bring additional threat for severe wx Saturday, but this threat is quite conditional - both on timing of any overnight convection and any additional disturbances aloft. There is good agreement in a pattern shift toward drier and warm conditions from Sunday into Monday as a strong closed low comes onshore from the Pacific and ridging over the South disrupts moisture supply to the Central U.S. This drier, warmer pattern may continue through mid week, but there is poor model agreement in how longwave troughs in the West and Canadian Rockies phase by Wednesday and beyond. && .AVIATION...(For the 06Z TAFS through 06Z Thursday Night) Issued at 1031 PM CDT Wed Sep 14 2022 VFR conditions are expected for the TAF period. Light showers are currently located along and west of the James River and will continue to move north/northeast into the overnight hours. Have left VCSH in KHON`s TAF due to the lingering light showers. The low level jet is currently strengthening, creating LLWS at all TAF sites. The LLWS will continue through the entire night before the low level jet weakens during the early morning hours tomorrow. Breezy southerly winds will continue through the night as well. No break from the breezy southerly winds as they continue through the day tomorrow. Another chance for showers and storms develops late morning tomorrow and continues through the day. Have included VCSH in all TAF sites as confidence in showers around KSUX has increased. However, confidence remains low enough at this time to preclude mentioning SHRA/TSRA in a TAF but trends will be monitored. Gusts drop off during the evening hours as the boundary layer stabilizes. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ SHORT TERM...BP LONG TERM...BP AVIATION...Meyers
Area Forecast Discussion
National Weather Service Lincoln IL
745 PM CDT Wed Sep 14 2022 .SYNOPSIS... Issued at 327 PM CDT Wed Sep 14 2022 Quiet weather will persist into this weekend as heat builds into the upper 80s. The next best chance for rain arrives Sunday night into Monday as a weak disturbance pushes through the region. Otherwise, the stretch of dry and progressively hotter temperatures will continue into next week. && .UPDATE... Issued at 744 PM CDT Wed Sep 14 2022 Main concern overnight is fog potential spreading south from northern Illinois and Indiana. Latest hi-res guidance continues to hint at this possibility as far south as the I-74 corridor and across portions of east central Illinois, but most of central Illinois will remain fog free. Outside of this potential, expect quiet weather conditions overnight to continue on the western periphery of a ridge axis. Temps will fall into the mid to upper 50s. && .SHORT TERM...(This evening through Thursday) ISSUED AT 327 PM CDT Wed Sep 14 2022 Upper level ridging centered over Arkansas early this afternoon will be edging eastward, with the ridge axis over Illinois by Thursday morning. Large area of smoke remains in place over the central U.S., and latest HRRR smoke output continues with the thicker smoke layer passing further north across the Great Lakes through tonight. Kept with the higher sky cover amounts introduced earlier based solely on the smoke, as not much in the way of cloud cover is expected until the ridge axis shifts east. Included a mention of patchy fog again late tonight along the eastern and northern fringes of the forecast area. However, HREF output favors the northern quarter of the state with low clouds and fog, aided by a bit more of a moisture feed off Lake Michigan in the wake of a lake-enhanced front. With more of a southerly flow picking up on Thursday, humidity levels will be a bit higher than recent days, with temperatures up a few degrees from today. .LONG TERM...(Friday through Wednesday) ISSUED AT 327 PM CDT Wed Sep 14 2022 The upper-level ridge will continue to break down and shift eastward through Friday as shortwave energy ejects across the Plains ahead of a deep Pacific trough moving onshore. Most of this shortwave energy ahead of the main wave will be deflected north and west of our area as central Illinois remains on the periphery of the upper ridge. The net effect will be continued dry conditions through at least Saturday. Surface wind gusts will begin to increase Friday into Saturday as the geopotential height gradients tighten in between high pressure anchored over the SE U.S. and developing low pressure lifting across portions of the Central Plains and Upper-Mississippi Valley. Occasional gusts to 25 kts are likely Friday, with more frequent 25 kt gusts expected Saturday. Temperatures will continue to surge warmer Friday and Saturday as 18degC 850-mb air advects into the region from the Southern Plains. With sufficient mixing, this should correlate to afternoon temperatures between 85-90degF with overnight lows cooling into the mid 60s. Predictability concerns begin to creep in by Sunday night after what is likely another dry and unseasonably warm day. In the upper levels, the pattern will become more amplified as the Polar Jet Stream buckles over the West Coast and heights rapidly increase across much of the central U.S. Most of the 12z suite of global guidance continues to exhibit shortwave energy rippling through veering mid-level flow. Though most of this forcing is displaced north of our area, it will be enough to drive a surface trough through our northern half late Sunday night into Monday morning. While BUFKIT soundings reveal considerable dry air in the lowest few km, scattered high-based convection cannot be completely ruled out. By Monday afternoon, global and ensemble guidance show central Illinois positioned beneath another anomalous upper ridge. This will shut off the precip chances and bring the onset of even hotter temperatures. Latest NBM guidance suggests low 90s Monday and Tuesday, and we see no reason to stray away from this guidance given the unusual late summer air mass in place. A quick glance at climatology confirms that this won`t be record-breaking heat, but we`re not far from it. Considerable differences are noted among global guidance by late next week. WPC`s Cluster Analysis Tool, which links together similar solutions, shows about 55% of ensemble members favoring continued hot and dry conditions into late next week as the ridge remains positioned over the Southern Plains, while the other 45% of members favor a cooler and wetter solution with the ridge breaking down. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 622 PM CDT Wed Sep 14 2022 Central Illinois will be on the western periphery of a ridge that extends from the eastern Great Lakes across the upper Ohio River Valley. Light and variable winds overnight will be replaced by a modest south breeze during the day Thursday. Some fog development may spread south from northern Illinois to near the I-74 corridor but the chance for vsby impacts on station is too low to include in the TAF at this time. Otherwise VFR conditions will prevail through the period with mainly cirrus expected. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Deubelbeiss SYNOPSIS...MJA SHORT TERM...Geelhart LONG TERM...MJA AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service Indianapolis IN
1154 PM EDT Wed Sep 14 2022 ...Updated Aviation Discussion... .Forecast Update... Issued at 945 PM EDT Wed Sep 14 2022 Forecast is in good shape this evening, with high pressure remaining in control. Only expecting a few high clouds tonight, along with light surface winds. These conditions will be conducive to fog formation tonight, and once again some dense fog is possible. By this time last night, some fog had already formed in Indiana, but nothing is seen in surface observations at the moment. Hi-res short term guidance has less coverage of dense fog tonight compared to Tuesday night as well. Thus, at the moment feel there is no need to issue a Dense Fog Advisory for later tonight. Will continue with a Special Weather Statement highlighting the threat for areas of dense fog. Will keep a close eye on surface obs through the night. Tweaked low temperatures some based on latest trends, but no significant changes were made. && .Short Term...(This evening through Thursday) Issued at 243 PM EDT Wed Sep 14 2022 Highlights... * Areas of Dense Fog late tonight into tomorrow morning. * Dry, mostly clear with increasing temperatures Rest of Today... The remainder of today will be quiet with near calm conditions. A 1500m saturated layer has developed near the PBL height due to an elevated subsidence inversion. This has lead to suppressed diurnal cumulus over most of central Indiana. These scattered clouds will dissipate quickly this evening as a new inversion develops within diurnal cooling. Highs will be in the low 80s, dropping steadily after 4PM into the upper 60s by late this evening. Tonight and Tomorrow... The main forecast problem tonight will be the formation of ground fog as the near surface approaches and reaches saturation. The formation of diurnal cumulus within strong subsidence this afternoon hints at an elevated layer of moisture, of which should limit dry mixing overnight. In return, dewpoints should stay in the mid to upper 50s throughout central Indiana. A dew point depression of 20-25 degrees should be easily overcome within efficient diurnal cooling, leading to a nearly saturated shallow surface layer late tonight into tomorrow morning. With minimal winds expected, fog should quickly develop over most of the region. There is still some uncertainty in the extend and thickness of said fog given subtle microscale factors, but confidence is increasing on at least patchy dense fog over all of central Indiana. For now, a SPS will be utilized to communicate fog potential/impacts, with further analysis later this evening on if an advisory is needed. The upper level ridge and high pressure will remain over the Ohio Valley for tomorrow. The overall airmass looks to be rather similar with a typical temperature curve, peaking in the low to mid 80s in the afternoon. Any remaining fog should flush away by 10am tomorrow morning through PBL expansion and mixing. Analysis of HRRR integrated smoke indicates an elevated layer of smoke, trapped within the upper level high, will push into the Ohio Valley tomorrow. This should have minimal impacts at the surface, but slightly hazier skies, and an increased sunset spectacle in the evening are likely. && .Long Term...(Thursday night through Wednesday) Issued at 243 PM EDT Wed Sep 14 2022 * Above normal temperatures into next week. * Largely dry except Sunday night into Monday. Ridging at the surface and aloft will set the stage for broad southerly/southwesterly low level flow over the weekend into next week, with a prolonged stretch of above normal temperatures expected as a result, with highs generally in the 80s each day (with a few low 90s readings possible), and lows generally in the 60s, save for tomorrow night when lows in the mid to upper 50s can be expected. The ridge aloft will gradually deamplify during the period, although the broad southwest flow will remain in place as it does so. This will leave the area largely dry throughout the long term portion of the forecast, save for late in the weekend into early next week. Deterministic guidance diverges a bit in its placement and intensity of a broad upper level wave expected to move through the Great Lakes Sunday night into Monday, and thus can justify no more than chance pops during this period. Convective indices suggest thunder potential and will carry this in the grids as well. The system should be progressive enough to prevent any prolonged rainfall or significant hydrologic potential, and this likely represents the only opportunity for rainfall through the seven day forecast. && .Aviation...(06Z TAF Issuance) Issued at 1154 PM EDT Wed Sep 14 2022 Impacts: * IFR/LIFR conditions in fog expected early Thursday morning. Discussion: GOES16 shows clear skies across the taf sites late this evening. However, dew point depressions were already approaching 2F or less. Light to calm winds are expected overnight due to a strong area of high pressure over Ontario stretching across the Ohio valley to the deep south. This will result in ideal radiational cooling overnight and areas of fog will form once again. Fog will be IFR/LIFR and confidence is higher at LAF/BMG/HUF due to the urban heat island effects of IND. VFR will return by mid morning on Thursday as daytime heating resumes. This will quickly burn off the diurnal fog. The large surface high pressure system will continue to provide dry weather on Thursday as forecast soundings continue to indicate a dry column along with unreachable convective temperatures. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...50 Short Term...Updike Long Term...Nield Aviation...Puma
Area Forecast Discussion
National Weather Service Lubbock TX
623 PM CDT Wed Sep 14 2022 ...New AVIATION... .SHORT TERM... (This evening through Thursday) Issued at 139 PM CDT Wed Sep 14 2022 18Z upper air analysis depicts a negatively-tilted trough pivoting over the Intermountain West with several smaller-scale shortwave perturbations embedded within the broadly cyclonic flow. Further east, shortwave ridging continues to translate eastward over the Osage Plains and into the Ozark Plateau, with the monsoonal fetch situated between the broad, negatively-tilted trough; and the departing shortwave ridge. At the surface, a broad moist sector is in place across the CWA with breezy, southerly winds near 15-25 mph in response to the sharpening trough located in vicinity of the Mescalero Escarpment and extending poleward into the Nebraska Panhandle. There are no fronts or surface cyclone features near the CWA; however, the presence of the surface trough will serve as a focus for thunderstorm initiation this afternoon near the Texas/New Mexico state line as low-level confluence and convergence increases beneath the ejecting shortwave trough. Moist, isentropic ascent has contributed to the ongoing showers in the mid-levels which has been the culprit of the cirrus debris, and shallow, surface-based cumulus have started to develop over eastern New Mexico as per latest visible satellite imagery. The expectation is for scattered showers and thunderstorms to develop near or after 21Z along the surface trough, with cold pool mergers facilitating perhaps a few broken lines or clusters surmounted by a well-mixed boundary-layer with PBL heights nearing 750-700 mb this afternoon. GOES-East Blended Total Precipitable Water imagery detects a plume of PWATs near 1.20" advecting northward across the Caprock, which also coincides with recent RAP analysis estimates. While PWAT content remains below the 99th percentile (as per interpolated 15/00Z climatology from the AMA and MAF RAOB sites), tall and skinny thermodynamic profiles with MUCAPE values near 1,500 J/kg west of the I-27/HWY-87 corridors amidst favorable warm cloud-layer depths will result in heavy rainfall with the deepest cores, with rain rates potentially exceeding 1"/hr, especially across the western zones where coverage of convection is greatest. The strongest cells will also be capable of producing wind gusts in excess of 50 mph and a rogue, severe- caliber gust or two cannot be ruled out either but the overall severe thunderstorm risk is low. Convection is forecast to decrease in coverage as it nears the I-27 and HWY-87 corridors late this evening as the PBL stabilizes from the cessation of diabatic heating/vertical mixing, and the potential for convective wind gusts will decrease thereafter. However, locally heavy rainfall will be possible through at least midnight before thunderstorms collapse altogether with residual showers lingering overnight as additional shortwave perturbations eject overhead and therefore maintain the moist, isentropic ascent throughout the low- and mid-level theta surfaces. Similar sensible weather conditions are expected tomorrow as the airmass remains largely the same despite the convective overturning, and the thinking is that thunderstorm coverage will be less (i.e. isolated) as the trough axes shift eastward (e.g. increasing subsidence) and as high-level flow becomes less difluent. Low PoPs have been maintained across the northern South Plains into the extreme southern TX PH as the diffuse surface trough shifts eastward from its location today. Sincavage && .LONG TERM... (Thursday night through next Tuesday) Issued at 139 PM CDT Wed Sep 14 2022 Convection on Thursday afternoon into the evening is expected to be much more isolated than today`s anticipated convection. We will be in the wake of a departing short wave resulting in increasing subsidence aloft. In addition, very dry air will be advecting into the area from about 600mb on up. There will be some sharpening of the surface trough leading to low level convergence mostly on the caprock. A very narrow corridor of higher theta-e values will exist along this corridor of weak convergence generating mixed layer instability values around 500-1000 J/kg. With the very dry air aloft and a deeply mixed boundary layer, downburst winds will be a possibility with any isolated convection that does develop. For next week, models have quite literally flip flopped in regards to the position of the eastern CONUS ridge. The ECMWF and its ensembles want to hold the ridge nearly overhead next week allowing a fetch of monsoon moisture to stay to the west of the region. The GFS holds the ridge overhead as well for the first part of the week and then moves east during the second part of the week. The corresponding ensembles reflect more of the ECMWF solution holding the ridge overhead. There may still be hope late next week if the ridge can move far enough east to allow moisture to stream overhead. Temperatures will likely stay above seasonal averages through the next week with this ridge in place. Thickness will rise through the period keeping temperatures warm until possibly late next week. && .AVIATION... (00Z TAFS) Issued at 620 PM CDT Wed Sep 14 2022 First piece of lift and associated showers and thunderstorms a bit ahead of schedule and have mostly cleared KLBB and KPVW. Dry air downstream suggest storms may not hold together and reach KCDS. Meanwhile, the second piece of lift is rotating across eastern New Mexico with additional showers and thunderstorms developing west of the terminals. This lift looks to be less focused, so some questions regarding how widespread they will be. Decided not to hold onto the vague VCTS wording, but note that there remains a chance for TS to affect the terminals through the evening despite no TS mention in the official forecast. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...09 LONG TERM....01 AVIATION...07
Area Forecast Discussion
National Weather Service Missoula MT
251 PM MDT Wed Sep 14 2022 .DISCUSSION...Satellite loops this afternoon show smoke trapped in the region and especially trapped in most of the valleys. The stability caused by the smoke is quite evident when observing how many of the storms are weakening after moving into Idaho and northwest Montana. A low pressure system in northeastern Washington is sending a spoke of energy into north-central Idaho and western Montana, resulting in showers and isolated thunderstorms. Convection allowing models show varying coverage for storms today, and the lack of warming due to smoke continues to cause decreased confidence in a more widespread nature of the showers for the rest of the day. The HRRR smoke model shows some improvement in the smoke throughout the region, but also shows that smoke will remain trapped in most of the valleys. Cloud projections show periods of decreased cloud cover tonight, but also show increasing cloud cover from the southwest overnight. Rain amounts this afternoon and evening and the cloud cover forecast are important aspects of the fog forecast for tonight and Thursday morning. Places that have at least some clearing and rain will most likely have a return of fog, but overall the impact from fog should be less than this morning. Another focus for rain is showing up for Thursday, mainly for points south of I-90, with a mid-level circulation that is expected to develop in southwest Montana. Thunderstorms are possible especially where there is less smoke. The strongest storms have a 10-20 percent probability of producing heavy rain during Thursday afternoon. Shower and isolated thunderstorm chances return for Friday. Model guidance agree on near to below average temperatures during this weekend, but there is still a big range on how much precipitation will occur. && .AVIATION...A low pressure system in northeastern Washington is sending a spoke of energy into north-central Idaho and western Montana, resulting in showers and isolated thunderstorms. Showers and thunderstorms will become more widespread through the afternoon and evening across all of western Montana and central Idaho. Smoke is expected to remain trapped in the valleys through tonight, though there may be a slow improvement in visibility beginning this evening. Fog is expected to return to some of the valleys tonight through Thursday morning, specifically those that have less cloud cover and receive moisture, but overall the impact from fog should be less than this morning. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$
Area Forecast Discussion
National Weather Service Reno NV
139 PM PDT Wed Sep 14 2022 .SYNOPSIS... The Mosquito Fire smoke will continue to produce smoke and subsequent air quality impacts through the week. Outside of the smoke, temperatures are autumn-like with chilly mornings and mild, typically breezy afternoons. Looking towards the weekend, we`re keeping an eye on the potential for a windy Saturday and a shower Sunday and Monday, and maybe some high elevation snow showers too. && .SHORT TERM... Well, I wish there was good news to share on the smoke front, but with the increased activity on the Mosquito Fire, there aren`t many positive things to share. Latest HRRR smoke simulations push another wave of dense smoke into the Reno/Carson City/Sparks locales between 4pm and 5pm today. A bit of north flow across west-central Nevada will transport the smoke across the Basin and Range overnight with widespread smoke for southern Pershing, Churchill, and Mineral counties, and possibly into eastern portions of Mono county as well. Tonight into Thursday will really `spread the wealth` of the smoke across much of western Nevada and the eastern Sierra. By Thursday afternoon, west winds may help to push out some of the smoke from the Basin and Range, but far western Nevada (Reno, Spark, etc) and the eastern Sierra will experience little reprieve. For the latest air quality information check You can also refer to your local Air Quality Management Division or the latest Smoke Outlook Statements from the US Interagency Wildland Fire Air Quality Response Program which are also available via: So let`s talk about something else! Ignoring the smoke, the temperatures and winds will be quite standard for this time of year, with cooler mornings and mild, breezy afternoons. Increasing dry west to southwest flow across the Sierra and western Nevada is pushing thunderstorm potential eastward this afternoon and evening with 10-15% chances of storms for southern Mineral and across the Basin and Range. -Edan .LONG TERM (Friday Onward)... A weak upper short wave will pass east across northern CA/NV on Friday and bring an increased chance for a shower or even isolated thunder along the northern Oregon border later that afternoon into the early evening. Other than a slight enhancement in afternoon westerly breezes in the north Sierra, this weak wave will pass mostly unnoticed except for the cooler afternoon highs in the low 80s for lower valley areas with mostly 70s across Sierra locations. The next upstream system will be noteworthy and a definite turn- around from the early September`s record heat. This anomalously deep short wave trough will drop south offshore the western US from the northeast Pacific through Saturday before lifting into the region later this Sunday into Tuesday. The vast majority of ensemble meteogram simulations project winds increasing to 35-45 mph over the Sierra and far western NV as pressure and thermal gradients respond to tightening height gradients aloft in the southwest upper flow. This will bring the potential for immediate impacts to both fire activity and smoke projections across the region, especially the Mosquito fire, as well as lake and recreational activities through the weekend. Although there is an increased potential for showers and precipitation over the region, timing and amounts remain the the main points of uncertainty Sunday through Tuesday. But there is at least a 30-50% chance of a few hundredths of an inch of some sort of precipitation falling mostly over the Sierra and far-western NV areas. As snow levels drop into the 8000’-9000’ range, some higher Sierra ridges could see close to an inch of white stuff adorning the higher peaks overnight Monday into Tuesday. One thing is for sure, much cooler more fall-like conditions are on the way. -Amanda && .AVIATION... * Most current hi-resolution models continue to show smoke and haze from the Mosquito fire affecting both surface and slant- range VIS Sierra and far western NV terminal through this forecast period. HRRR guidance projects a brief few hours of MFVR conditions late this afternoon giving way to thicker smoke lowering CIGS/VIS to mostly IFR and below in the vicinity of the fire and downwind for terminals north of I-80 during the overnight hours tonight into Thursday morning. But timing still remains an issue dependent upon on local winds and fire activity. * Terminals to the south will not be spared for long as smoke layers wrap around and settle south of US-50 and east of US-95 aft 06Z with periods of MVFR conditions in smoke and haze for KCXP and KMEV. Further south along US-395 in the eastern Sierra to include KMMH will remain unaffected by smoke with VFR conditions continuing through the forecast period. * A slight risk for a thunderstorm or two lingering into the evening hours continues in southern Mono County and east of US-95 in Churchill/Mineral Counties. Typical zephyr breezes with gusts near 20 kt are still expected for terminals near US-395 through this afternoon, with lighter winds overnight into Thursday. -Amanda && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$
Area Forecast Discussion
National Weather Service San Diego CA
130 PM PDT Wed Sep 14 2022 .SYNOPSIS... Dry weather will prevail through early next week with mostly below normal daytime temperatures. Areas of night and morning coastal low clouds and fog will extend inland across much of the valleys and occasionally onto the lower coastal mountain slopes. Upper level low pressure moving to near the West Coast could bring slight cooling early next week followed by warming the second half of next week after the low moves inland. Locally gusty west winds will occur at times in the mountains and deserts through early next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Partly cloudy conditions prevailed with a mix of some lingering stratus near the coast, some stratocumulus in the valleys and cumulus in the mountains. It was mild at early afternoon with temperatures mostly in the 70s to mid 80s west of the mountains with only lower to mid 90s in the hotter lower desert locations. We are back in the onshore flow marine-layer pattern, though we had no strong marine inversion this morning (though there were 2 inversions, one around 1500 feet, the other around 5000 feet MSL). This is expected to continue, so the marine layer stratus will likely not be solid the next few days, and the HRRR cloud ceiling maps confirm this, so some locations even near the coast have sunshine quick early Thursday morning. Most coastal locations have hourly NBH 3000-foot or below cloud ceiling probabilities of only 60- 75 0 percent late tonight/early Thu and trending downward from previous runs. In contrast to earlier this month, high temperatures will be mostly 5-10 deg F below normal in most areas at least through early next week, though nighttime temperatures will be near or slightly above normal, partly assisted by the continued positive sea surface temperature anomalies in our coastal waters, albeit with some decline in water temps the past few days. A large upper low will be somewhere off the California coast this weekend with tropical moisture flowing north on the east side of the low. Models/ensembles have some disagreement with timing of the low, but regardless, impacts here will be minor other than perhaps a little drop in temperatures early next week and maybe a bit of drizzle from a deepening marine layer, but the ensembles are almost all agreeing that little or no precipitation will occur in our forecast area early next week. Moderate warming will likely occur after the low passes to the northeast in the middle or, more likely, the latter part of next week. && .AVIATION... 142010Z...Coast/Valleys...Patches of low clouds with bases 1500-2000 ft MSL impacting KSAN and KCRQ at this hour. Those CIGS could become SCT for periods of time this afternoon. Low clouds near coast will begin to increase in coverage after 03Z Thursday and spread up to 25 miles inland overnight into Thursday morning, with similar bases. Expect local vis 3-5SM on higher coastal terrain. Clearing from inland to the coast likely 17Z-19Z Thursday. Mountains/Deserts...SCT-BKN clouds at or abv 10000 feet through this afternoon. && .MARINE... No hazardous marine conditions are expected through Sunday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...Maxwell AVIATION/MARINE...PG