Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/11/22

Area Forecast Discussion
National Weather Service Des Moines IA
923 PM CDT Sun Jul 10 2022 .UPDATE... Issued at 922 PM CDT Sun Jul 10 2022 ...Potential for strong, gusty winds and hail in the pre-dawn hours Monday into Monday morning daytime hours... This evening, keeping a close eye on model trends as it pertains to the convection that may impact our area in the pre-dawn hours Monday into the rest of Monday morning. Storms have initiated late this afternoon over south central and southwest Nebraska and far northeastern Colorado with the first severe thunderstorm warning issued a little before 1z. Convective allowing models show these storms advancing eastward this evening and becoming a bit better organized in part due to the low level jet ramping up within the favorable instability and shear space. Questions that remain for our area and forecast are will these storms diminish as they often do through the overnight and what redevelopment may occur due to a shortwave trough that is approaching from South Dakota? Will the storms be elevated or still be able to reach the surface? The HRRR and 12z WRF ARW develop storms in a high MUCAPE environment, but also with plenty of surface based CIN. The storms that come into Iowa and reach our forecast area reach the Hwy 71 corridor around 4 or 5am and the Des Moines metro area by around 6 or 7am or so. Looking at the past seven HRRR runs (18z-00z), it has had a consistent signal of severe wind gusts (50+kts) for multiple runs (Admittedly, the 20z run peaked around 45kts.) and generally around a county to two wide somewhere between Highway 30 and Highway 34. While some HRRR runs show the storm weakening as it moves east or southeastward toward I-35 in central Iowa, will the storms truly outflow and gust out and weaken? Or, will it maintain balance with the cold pool and truck through the entire forecast area? Will the surface based CIN limit the wind gust potential? These are questions that are still lingering. While the mid-levels are warm, there are updraft helicity tracks in both the HRRR, WRF ARW, and delayed in the FV3 indicating rotating storms are possible. This could lead to supercells, which may cycle hailstones and allow them to survive the warm temperatures to the surface. Discussing with WFO Quad Cities and the Storm Prediction Center, we all agree that this is not a high confidence forecast, which is often the case with MCS in the warm season and the predictability of them. All of us will be watching trends overnight. Bottom line, this is a low probability, but possibly high impact wind event *IF* it were to occur with hail also possible. && .DISCUSSION.../Tonight through Sunday/ Issued at 235 PM CDT Sun Jul 10 2022 Key Messages: -Chance of storms tonight/Monday -Quiet the rest of the work week Upper ridge dominating the pattern over the southwestern CONUS with quasi-zonal flow over the northern states. Convection that crossed this morning northern Iowa this morning was riding along the northern edge of the ridge. Upper trough now crossing Montana will bring the next weather change for us later tonight into Monday. As it pushes into the midwest, this trough will nudge the ridge south. A weak short wave ahead of the main trough will bring a low chance of storms late tonight and early Monday morning. A better chance for storms will come on Monday, tied to the cold front (associated with the passage of main upper trough) due to better shear and instability. That said, models in the current pattern have been struggling to handle convective development, often underestimating the instability aloft so confidence is low in the details of how things evolve, especially tonight. Once the trough passes, we will enjoy northwest flow for a couple days, followed by then a notable warmup at the end of the week as the western ridge starts building back eastward. && .AVIATION.../For the 00Z TAFS through 00Z Monday evening/ Issued at 655 PM CDT Sun Jul 10 2022 Main aviation concerns are around storm chances, gusty winds, and some early VFR clouds. First, there is an area of clouds around FL045 or so moving southeastward which look to keep VFR conditions both at MCW and ALO. The gusty winds this afternoon will subside, but will become from the northwest and turn breezy again Monday afternoon as a cold front pushes through. First chance of storms will arrive from the west after 9 or 10z and last a few hours at any given terminal except perhaps MCW, which may miss out altogether. Given lack of confidence in location and exact timing, have chosen to maintain VCSH in this issuance with TS included in 6z issuance. After this round clears, an additional round of storms is possible later in the afternoon and looks most likely over the northern terminals. However, given this is late in the period, stuck with VCSH. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Ansorge/Krull/Jimenez DISCUSSION...Dubberke AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Quad Cities IA IL
950 PM CDT Sun Jul 10 2022 ...UPDATE TO ADDRESS MONDAY AM STORM POTENTIAL... .UPDATE... Issued at 947 PM CDT Sun Jul 10 2022 Will need to keep a close eye on potential convection across the area Monday morning per latest runs of CAMs. Over the course of the day, CAMs have been mixed on potential for storms over eastern Iowa into northwest Illinois around the 12-16 UTC time frame. Runs from the HRRR / NAMnest / ARW have been the most bullish on painting an intensity-varying cluster of likely MCV- driven thunderstorms capable of producing very gusty winds (see last several runs of the HRRR), and potentially large hail for an area between the Hwy 34 and Hwy 30 corridors. The progged environment is supportive for thunderstorm development with quite a bit of MUCAPE (very steep mid-level lapse rates in the 7-9 C/km range) and low- level convergence from a LLJ that will be in place from northwest MO into southern IA. That being said, the same models that generate this storm complex also do generate quite a bit of low-level CIN from the overnight surface inversion, which would make getting these analyzed winds down to the surface a bit more difficult unless the storms develop strong cold pools. In discussing with NWS Des Moines and SPC, we agree that while the confidence in this scenario unfolding is low, appropriate messaging should be made to address this potential. Those who have morning plans or will be out for the Monday AM commute should monitor the latest forecasts and trends overnight. && .SYNOPSIS... Issued at 251 PM CDT Sun Jul 10 2022 Isolated showers and storms dropped into the far northwestern counties earlier this afternoon, but in a weakening phase. Anticipate these showers to continue to dissipate over the next few hours. Otherwise, majority of the area will see dry and warm conditions this afternoon with highs in the low to mid 80s. && .SHORT TERM...(This Evening through Monday) ISSUED AT 251 PM CDT Sun Jul 10 2022 It will be quiet this evening into tonight with temperatures falling back into the 60s to low 70s. Then increasing convergence on the nose of a WSW low-level jet may guide a complex of showers and storms into the region late into Monday AM. This complex will initially form over central Nebraska this afternoon and cross central Iowa overnight. For timing locally, the best chances for rain are after 4-6 AM in the west, with the activity (assuming it holds together) spreading through central sections mid to late morning. Hi-res models are not in agreement on the areal coverage, so kept rain chances around 30 percent. Gusty winds and lightning would be the main concerns with this first round of storms. Scattered showers and storms may redevelop along a cold front during the afternoon and evening. Model consensus is for low coverage along the front, meaning much of the area could stay dry. The best chances for a few strong storms are across the far southeast to east-central portions of the outlook area during the late afternoon and evening. Here, the primary threat is for isolated damaging winds. Afternoon highs across the forecast area will reach well into the 80s with very humid conditions expected as dewpoints peak in the upper 60s to low 70s. .LONG TERM...(Monday Night through Sunday) ISSUED AT 251 PM CDT Sun Jul 10 2022 A brief cool down followed by increasing temperatures and humidity by next weekend. Monday night through Thursday night Assessment...medium to high confidence The cool front will exit the area early Monday evening and take any lingering rain with it. Comfortable temperatures will then be seen Tuesday into Wednesday. Right now the model consensus has dry conditions through Thursday night. However more models solutions suggest a weak back door front moving off Lake Michigan late Tuesday night or Wednesday. This front in combination with a passing upper level disturbance Wednesday afternoon `may` be enough to initiate diurnal convection. If this scenario does occur, coverage may be sparse with 90 percent of the area remaining dry. Friday through Sunday Assessment...high confidence with increasing heat/humidity. Low to medium confidence on rain chances. The heat and humidity starts arriving Friday and has the area fully engulfed over the weekend. Right now peak afternoon heat index readings look to be 95 to 100 this weekend but that could change. How bad the heat gets will be dependent upon the location of the heat dome and where any organized thunderstorm complexes develop/track. The model consensus has slight chance pops Friday through Saturday night across the northern half of the area with dry conditions Sunday. Internally there are signals from some of the models suggesting a decaying storm complex from the upper Midwest `may` get into the northern parts of the area Friday. If correct then there would be an effective boundary for nocturnal convection to develop along Friday night into Saturday. The ECMWF has been consistent with this scenario with the CMC global to a much lesser extent. The GFS has been inconsistent from run-to-run regarding the chances of rain. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) ISSUED AT 607 PM CDT Sun Jul 10 2022 Expect VFR conditions for all terminals through tonight with gusty south winds subsiding to under 10 knots. Monday morning, there will be a threat of rain showers (low confidence on storm potential) mainly at KCID/KMLI/KBRL as a shortwave moves into the area ahead of a cold front. Short term CAMs are in good agreement of this potentially impacting locations around Interstate 80 south to HWY 34, so have added a PROB30 mention in this TAF to the terminals in this vicinity. Confidence of this impacting KDBQ is low. Past this, winds will begin to shift to the northwest as the front nears the area. Brief gusts around 20 knots will be possible mainly at the terminals along and north of Interstate 80 Monday afternoon. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...Speck SYNOPSIS...Uttech SHORT TERM...Uttech LONG TERM...08 AVIATION...Speck
Area Forecast Discussion
National Weather Service Grand Forks ND
1032 PM CDT Sun Jul 10 2022 .UPDATE... Issued at 1032 PM CDT Sun Jul 10 2022 Mid level shortwave circulation is digging into western ND with increasing forcing spreading east through Monday. Mid level lapse rates remain weak, however ample BL moisture (Tds still in the 62-68F range) continues support elevated (skinny) CAPE profiles in the 1500-2000 J/KG range over our CWA based on RAP analysis. Westerly deep layer shear also remains in place (effective shear 35-50kt). Trends in RAP show this axis of instability weakening through the night and decreasing, however there is a window during that transition that parameters could still support a marginally strong/severe storm through roughly 3AM. Radar trends aren`t very impressive upstream though as cores have generally been shallow and ultimately most activity will likely be showers and non severe thunderstorms. Will continue to monitor. UPDATE Issued at 646 PM CDT Sun Jul 10 2022 We are starting to see trends that would indicating CU fields flattening/weakening locally, and with less favorable mid level lapse rates this trend should continue through sunset. We still have lingering instability and good unidirectional shear, but forcing has just been to weak in the wake of the earlier convection (just weak surface convection near lingering boundary in our northwest). Our best chance for any severe convection at this point will be with the activity in northwest ND moving east. HRRR continues to show a potential organization with that activity as it approaches the Devils Lake Basin before quickly weakening with sunset, so we will continue to monitor trends. After sunset forcing does begin to increase as the shortwave approaches, and scattered showers or a few weaker thunderstorms seem to be favored as much drier air combined with the already weak mid level lapse rates will be in place. && .SHORT TERM...(This evening through Monday night) Issued at 246 PM CDT Sun Jul 10 2022 Challenge continues to be convection and its evolution this afternoon and into the overnight. Afternoon convection fired along morning outflow and midlevel front within a favorable environment for elevated supercells with several severe hail reports over the past two hours. Will see this activity slide east and south with a question on potential the severe threat a weakening trend noted in the past 30 min. Attention then turns to the northwest this evening as the cold front provides forcing to the area. Convection is expected to develop in NW ND and southern Saskatchewan reaching the Devils Lake area in the 3 to 5Z time frame. Threat for marginally severe hail and wind potential exists as UH tracks per CAM guidance depicts stronger updrafts entering the NW FA then weakens as activity moves into the valley tonight. Monday the chance for showers and storms will persist across NW Minnesota with the cyclonic flow around the 500mb short wave. With minimal instability general thunderstorms are expected as breezy NW winds bring drier air into the area with dewpoints in the 50s working into the FA tomorrow. .LONG TERM...(Tuesday through Sunday) Issued at 246 PM CDT Sun Jul 10 2022 IMPACTS... 1.) Heat returns once again to the area. High temperatures in the 90s this week are in store for us with low temperatures pushing the upper 60s/low 70s. SYNOPTIC ANALYSIS... Large scale ridging will return to the area this week across much of the CONUS. This will at least keep large scale synoptic forcing away from the area, thus minimizing widespread thunderstorm potential. Having said that, with temperatures rising into the 80s and 90s with dewpoints not expected to fall off too terribly much, the potential is there for isolated thunderstorms here and there. Better precipitation chances arise late week with ensemble guidance indicating a potential shortwave/ridge rider, however predictability is low in location as it will depend on the amplification of the ridge. Other than that, primary concern will be the return of heat later this week. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 634 PM CDT Sun Jul 10 2022 VFR conditions should prevail across eastern ND through the TAF period, with potential MVFR ceilings at times in MN (especially Monday morning). There is still potential for a few showers or thunderstorms across the region, with best thunderstorm potential this evening near KDVL and better shower chances in northwest MN Monday morning. Winds have shifted to the northwest and a period of gusty winds should develop during the daytime period Monday well behind the cold front (after it passes later tonight). && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...DJR SHORT TERM...JK LONG TERM...Perroux AVIATION...DJR
Area Forecast Discussion
National Weather Service San Francisco Bay Area
506 PM PDT Sun Jul 10 2022 .SYNOPSIS...Temperatures are expected to be warm Sunday and Monday, with hottest temperatures in farther interior locations. The King Tides return this week with lowest low tides and highest high tides peaking around Wednesday night and Thursday morning. Another modest warming is forecast for late in the week through next weekend. && of 01:42 PM PDT Sunday...Clear skies are seen on satellite over the Bay Area, while stratus remains tightly hugged along the Pacific Coastline. High pressure has been steadily growing over the last 24 hours. It is a result of the upper level ridge that is situated just east of the Four Corners. Temperatures at 850 mb will warm to around 18 to 23 degrees Celsius on Sunday, and possibly up to 25 degrees on Monday for slightly warmer conditions. With these temperatures expected to mix down, much of the interior areas are forecast to be in the 80s and 90s. At the time of writing this discussion area temperatures have already been observed to be around 10 degrees warmer than at the same time yesterday. There remains a slight chance for low 100s, but it will be limited to far interior areas near the Central Valley. It is recommended that outdoor activities should remain limited, or if they must continue that it is advisable to take breaks in areas of shade and stay hydrated. Meanwhile, perpetual breezy onshore winds should limit warming conditions along the coast. Stratus should remain over the ocean, but with the high pressure compressing the marine layer, Monday and Tuesday morning could spell another round of isolated patchy fog. The Washburn Fire continues to burn in Yosemite National Park, showing a clear smoke plume on satellite imagery. Winds aloft are slowly pushing the smoke northward toward Lake Tahoe. As the ridge strengthens on Monday, winds aloft will have a more southeasterly component to it. The HRRR Vertically Integrated Smoke model provides a chance for some of that smoke to drift over Eastern Contra Costa County and Napa County on Monday morning. But due to surface winds being onshore, there is low confidence for surface level impacts. Much of the smoke should remain aloft creating only slightly hazy skies. This upcoming week also provides the summer installment of the return of the King Tides. Lowest low tides are expected in the mornings, while the highest high tides are expected in the night. Nuisance flooding can be expected along the coast and particularly the Bay Shoreline, so a Coastal Flood Advisory has been issued for the low lying areas near the water. For more information, see the BEACHES section of the AFD below. The previously mentioned upper level ridge takes up residence over the four corners Wednesday into Thursday. Meanwhile models are projecting the next upper level shortwave trough to dip down and through Northern California. Once the short wave passes northeastward, the parent longwave trough looks to re-establish itself and shifting somewhat eastward. These troughs will keep onshore flow and a fairly well defined marine layer through the work week. Temperatures will cool slightly, but remain summer time warm through the week. The ridge will attempt to move westward again at the end of the week and into the weekend, but at this time there is low confidence in any real substantial heating to pose the threat of any heat risk. However, it could be just enough to nudge temperatures slightly warmer by next weekend. Beyond that, the Climate Prediction Center keeps the Bay Area with the chance for above normal temperatures in the the 8-14 days outlook and at-or-below normal chances for precip. And based on ensemble guidance, it is fair to assume that any precip chances will remain along the immediate coast in the form of just patchy drizzle that is squeezed out from the marine layer/fog. && .AVIATION... As of 5:00 PM Sunday... For the 0Z TAFs. Satellite imagery is showing the stratus layer peeling away from the North Bay coast, while mostly hugging the coast towards the south of Point Reyes, intruding inland around the northern San Francisco Peninsula and the Monterey Bay coast near KWVI and KOAR. The stratus layer is expected to build back overnight with IFR ceilings expected at KAPC and the Monterey Bay terminals. Medium confidence of IFR ceilings at KOAK as well, with the main support coming from LAMP guidance and persistence from last night. Stratus expected to dissipate Monday morning around 16-18z with winds becoming breezy in the afternoon. Vicinity of KSFO... VFR through the rest of the day with breezy winds around 20 knots. Marine stratus is expected to push through the Golden Gate, but confidence is low that it will wrap south onto KSFO. Although HREF is not showing a high probability for impactful ceilings, have kept TEMPO group in to maintain consistency with previous forecast, as well as a persistence forecast. Any ceilings should lift in the morning, with winds quite breezy from the west. KSFO Bridge Approach... Stratus impacts are even less likely south of KSFO. Otherwise similar to KSFO. Monterey Bay... VFR with breezy winds for the rest of the day. IFR ceilings expected to fill in overnight, with medium confidence for LIFR ceilings and perhaps visibilities in the early morning hours. Ceilings burn off in the morning with winds around 10 knots from the west in the afternoon. && of 1:30 AM PDT Sunday...Increasing tidal levels may lead to minor coastal flooding this week. This potential is greatest for vulnerable, low-lying, portions of the San Francisco bayshore which typically experience King Tide flooding. Impacts are possible during high tide cycles from July 11th-16th, with peak levels expected towards the middle portion of the week. As such, a Coastal Flood Advisory has been issued for areas along the San Francisco Bay Shoreline. && of 05:05 PM PDT Sunday...Moderate NW winds and locally steep hazardous seas continue across the waters tonight, with the strongest gusts in the northern outer waters, along the Big Sur coast, and through the Golden Gate. Winds will diminish through Monday morning becoming light over most of the waters by Monday afternoon. Otherwise, locally gusty winds remain likely around the Golden Gate and North Bay, the coastline south of Pigeon Point, and the Big Sur coast. A moderate period southerly swell remains in the background while driven seas dominate the sea state. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tday...Coastal Flood Advisory...CAZ006-506-508 SCA...Pt Arena to Pigeon Pt 10-60 nm until 9 AM SCA...Pt Arena to Pt Reyes 0-10 nm until 3 AM SCA...SF Bay until 9 PM SCA...SF Bay from 3 PM && $$ PUBLIC FORECAST: DK AVIATION: Dial MARINE: Behringer Visit us at Follow us on Facebook, Twitter, and YouTube at:
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 300 PM CDT Sun Jul 10 2022 Early afternoon analysis showed surface low pressure over the eastern Dakotas with an attendant cold front extending southwestward into the NE panhandle. Ahead of this front, some clouds and spotty light radar returns were noted, associated with one or all of a pre- frontal trough, low level frontogenesis, and/or a subtle shortwave seen in water vapor imagery. Regardless, not much impact from these other than perhaps keeping things a degree or two cooler for a bit and an isolated sprinkle, owing to a very dry sub-cloud layer. Otherwise, it was a hot and humid July day out there, with temperatures as of 3 PM ranging from the mid 80s in IA to the 90s and around 100 in portions of northeast NE. With the warm, humid air mass in place and a cold front sliding in this evening, strong to severe storm chances will be the main forecast concern in the short term. The general idea is that storms will go up along the boundary this evening and then push eastward overnight, perhaps as a cluster/line. With the strongest deep layer shear looking to remain behind the front, storms may be a bit disorganized, but given the amount of instability and model soundings showing inverted-v profiles, severe storms capable of damaging downburst winds and possibly some quarter-sized hail will be possible. While it seems like a somewhat straightforward setup initially, several questions remain: 1) How far east do storms initiate this evening? Soundings show a fairly stout cap that will need to be overcome, but strong low level flow will continue to provide plenty of mixing. Consensus of latest short term guidance keeps initiation west of the forecast area, but something to watch. 2) Will storms that develop over western NE hold together and push into the forecast area overnight and will they be severe? Several CAMs, including many consecutive runs of the HRRR show a line/cluster of storms pushing into the area around or just after midnight. Raw wind gust output from the HRRR reveals a broad swath of 50+ kt winds and even some pockets of 60 kt winds, and while it`s never a good idea to count on raw wind gust output verifying, it does give an idea of the higher end of potential gusts. Do think time of day/boundary layer cooling would keep these stronger winds from reaching the surface, however, thermodynamic profiles overnight show plenty of DCAPE with no DCIN, so it seems there would be a threat for damaging winds overnight assuming storms hold together. 3) Will an outflow boundary race out ahead of storms and bring a damaging wind threat and/or provide a focus for additional storm development? While 0-3 km shear of 25 to 30 kts should keep the outflow relatively close to the storms (pending orientation), a few CAMs (e.g. 10.12Z NSSL-WRF) seem to hint at the potential for spreading outflow boundaries, which could bring "surprise" strong to damaging winds ahead of storms. Also given the warm, moist airmass in place, it could provide just enough additional forcing for more storms to develop, despite the capping in place this evening. So bottom line, there seems to be 2 windows for severe weather. The first being this evening if storms develop near/over the area and the second being overnight as storms move in from western NE. If the first scenario occurs, the later storms would likely have a lesser chance of being severe, if they hold together this far east at all. The front looks to clear the area Monday with morning showers and storms helping it to advance farther south. A secondary line of showers and perhaps a few storms also looks like it could slip the area through the afternoon as the main mid-level trough axis slides by to the northeast. Given the frontal passage and shower potential through the day, expect a cooler day with highs generally in the mid 80s. Surface high pressure looks to dominate on Tuesday and lead to a quiet summer day. Highs look to be in the mid 80s to around 90 and humidity should be manageable, with dewpoints in the 50s to lower 60s. Mid to upper level ridging will then build in through the remainder of the week with increasing temperatures heading into the weekend. By Friday, guidance is in good agreement we make a return to widespread 90s and perhaps a few 100s along with increased humidity making a return. The overall pattern should favor largely dry conditions, though there may be a few occasional shots for precip as various bits of shortwave energy slide through. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 601 PM CDT Sun Jul 10 2022 Southwesterly flow at 12-24 knots at TAF issuance, but diminishing to around 9-10 knots by 01z. Showers/isolated thunderstorms could develop at KOFK by 05-06z, and KLNK/KOMA by 07-08z, lingering through 14-15z. Winds then becoming northwest to north through the TAF forecast, eventually increasing to 20 to 23 knots by 17-19z. And there could also be spotty showers at KOFK 19-21z, but also too far out to mention at this time. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...Heat Advisory until 8 PM CDT this evening for NEZ011-012-015>018- 030>032-042-043-050-065-078. IA...None. && $$ DISCUSSION...CA AVIATION...DeWald
Area Forecast Discussion
National Weather Service Reno NV
1211 PM PDT Sun Jul 10 2022 .SYNOPSIS... Temperature trend will be upwards through much of the week. Triple digit heat likely for much of western Nevada Monday into Wednesday, with above average temperatures elsewhere. Areas of haze and smoke will continue to be concerns through the week. A few afternoon thunderstorms are possible from Tuesday into Saturday with low chances for very localized rain. The primary concerns will be lightning and gusty winds. && .DISCUSSION... * THE SMOKE: North and east winds pushed smoke from the Washburn Fire mostly west of the Sierra crest today providing a bit of relief for western Nevada. Unfortunately, based on the latest HRRR simulations this will be a short break. Our more typical west winds are projected to return and sweep the smoke back into Mono and Alpine counties first and then into the Tahoe Basin, Douglas, and Lyon counties Monday evening into Tuesday Morning. I will be squeezing in my outdoor activities Monday morning before it`s too hot and the smoke comes back. Keep an eye on for the latest air quality conditions during these periods of haze/smoke. * THE HEAT: It is heating up out there with lower elevations well on their way to the mid to upper 90s today. Additional warming will take place Monday into Wednesday, especially for the US-95 corridor, with many locations likely to hit or surpass 100 degrees. Blended model guidance continues to show a 30% probability of triple digits for Reno on Monday and Tuesday. For areas along and east of Highway 95 the possibilities are much higher with a 60% chance for Monday and Wednesday and 80-90% chance for Tuesday. While overnight lows will cool into the 60s for most lower elevation sites, it will still be pretty warm through at least Wednesday. Temperatures will begin to taper a bit later into the week and the weekend, but will still remain above average. * THUNDERSTORM POTENTIAL: With the increased heat on Monday, we can`t rule out a cumulus cloud or two popping up along the Sierra, but the potential for a shower or storm area very low (<5%). On Tuesday, a weak upper level wave will rotate around the periphery of the ridge resulting in enhanced potential for isolated thunderstorms on Tuesday. Thunderstorm nature will be fast-moving, with little to no rainfall and a high probability of gusty and erratic outflow winds. In the span of the week, Tuesday appears to be the best-looking day for thunderstorms. By Wednesday, the dry, southwest flow associated with an approaching trough off the West coast will really "shut it down" when it comes to thunderstorm potential. Slight chances may hang on for areas in southern Mono and Mineral counties. Later in the week with the trough off the coast and high pressure hanging on across the four corners, the Sierra and western Nevada may remain right on the edge of the thunderstorm potential. Additional waves sweeping through the ridge or trough may help to facilitate thunderstorms to develop from Thursday into the weekend, but again the chances would remain confined to southern Mono and Mineral Counties. -Edan && .AVIATION... VFR conditions prevail with light winds and afternoon gusts 10-15 kts. Areas of smoke, notably around the Tahoe Basin and along the Sierra, will continue to advect westward out to the Central Valley this afternoon into tomorrow as light easterly flow prevails. Some haze may linger in spots, leading to reductions in slantwise visibility. Depending on fire activity and suppression progress tomorrow, smoke may return on Tuesday morning as a trough off the Pacific NW coast ejects a shortwave into the region late Monday and ramps up southwest flow across the region. The HRRR smoke model currently shows dense near-surface smoke around KTVL-KCXP-KMEV-KMMH terminals Tuesday morning. Afternoon Zephyr westerly winds continue from Tuesday onward, with gusts 20-25 kts. A few gusts up to 30 kts are possible through the week. Thunderstorms are possible on Tuesday as well, with chances 10- 20% for KRNO-KCXP-KMEV-KMMH, and less than 10% for KTRK-KTVL. -Whitlam && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Tucson AZ
257 PM MST Sun Jul 10 2022 .SYNOPSIS... Hot temperatures with near record highs and isolated afternoon thunderstorms to start the week. Temperatures will still remain well above average as the chance of storms increases through the week. && .DISCUSSION...This Week. Ridge will remain centered near the intersect of CO/OK/NM/TX today with moisture levels still slightly below average for this time of year. PWAT values are hovering between 0.9"-1.3" according to latest RAP analysis. Instability is focused east and south of Tucson where SBCAPE values between 1000-2000 J/kg are located. This will be enough for some scattered showers and storms to pop with even one or two storms becoming strong but overall it should be a relatively quiet day with localized storm impacts. Temps this afternoon will reach well above normal and challenge daily records in some locations. On Monday the ridge will split with a western center over northern AZ/southern UT. The heat will continue and Monday is expected to be the hottest day this week topping out a couple degrees higher than today. With HeatRisk approaching the "High" level and therefore potentially impacting much of the population, an Excessive Heat Warning has been issued for the Tucson Metro, central/western Pima County, and portions of southeast Pinal County on Monday. Regardless, precautions should be taken everyday for the heat as temps will continue to be above normal each afternoon this week. With ridge to the north, flow will shift to the east to northeast on Monday. Instability increases slightly on Monday with PWAT values fairly consistent but there will be the addition of an easterly wave passing in the vicinity of the area which could help things along into the overnight hours going into early Tuesday. With the shift in the flow, CAMs are beginning to pick up on a Mogollon Rim event where storms develop on the rim then move southwestward off the higher elevations throughout the day and into the evening. This would put the Tucson Metro in the cross hairs between about 6 PM-9 PM on Monday. Strong winds, brief heavy downpours, and visibility reductions due to dust will be possible with this line of storms. This rim activity will be in addition to the regular convection over the higher elevations of Cochise and Santa Cruz counties during the early to mid afternoon. Tuesday through Saturday...Ridge will waver around the Four Corners region for much of the week, weakening by mid week as trough moves into the eastern Pacific. This will allow for typical mid-July storm coverage each day this week with some days favoring southwestern Arizona and others favoring the eastern Arizona border. Temps will continue to run a couple degrees above normal. && .AVIATION...Valid through 12/00z. SCT -SHRA/-TSRA are expected to develop through 11/03Z mainly east and south of KTUS impacting KOLS between 10/22z-11/03z. SFC winds generally less than 12 kts with the exception of gusts up to 40 kts near -SHRA/-TSRA. SCT-BKN clouds at 10k-12k ft will prevail through 06z with FEW clouds down to 7k-9k ft. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... A gradual increase in monsoon moisture will lead to an upswing in shower and thunderstorm activity this week. Very hot temperatures will start the week with near daily record highs expected for today and Monday. Temps come down a degree or two after Monday but will remain above normal for the remainder of the week. Minimum RH values will drop to 10-20 percent this afternoon and again on Monday before gradually increasing through late this week. Outside of thunderstorms, 20-ft winds will remain at or below 15 mph. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning from 10 AM to 8 PM MST Monday for AZZ501- 502-504-505. && $$ Guillet Visit us on Facebook...Twitter...YouTube...and at