Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/04/22

Area Forecast Discussion
National Weather Service Bismarck ND
935 PM CDT Sun Jul 3 2022 .UPDATE... Issued at 935 PM CDT Sun Jul 3 2022 We issued a Flood Watch from Sioux and Emmons Counties eastward through Logan, McIntosh, LaMoure, and Dickey Counties in response to potential training, clustered convection moving through that area the next 3-6 hours. Low-level moisture transport focused in that area and high precipitable water values around 1.5 inches is a favorable heavy-rainfall and potential flash flooding setup in that area. Otherwise, with this update we only made minor changes to the forecast. Severe-storm risk is ramping up as expected with two primary regimes, a mix of supercells and bowing segments that will enter southwestern ND shortly and the more clustered/training storms in far south central ND lifting northward with time. MESOSCALE DISCUSSION Issued at 807 PM CDT Sun Jul 3 2022 Early evening surface analysis reveals a surface low southeast of Billings, MT, and a quasi-stationary frontal zone extending to the east-northeast across southeastern MT and into southern ND roughly along the I-94 corridor. An old outflow boundary is located across northern SD, and there`s a subtle area of slightly lower dewpoints (lower versus middle 60s F) in northern SD near that boundary, and the 00 UTC Aberdeen RAOB sampled weak bouyancy in that corridor in comparison to the moderate MLCAPE sampled at Bismarck. This likely explains why the storms in north central/northeastern SD have had a difficult time intensifying -- but also suggests that as storms gradually propagate and/or develop into south central and southeast ND along and south of the quasi-stationary boundary that they will be in a more favorable thermodynamic environment for intensification. Both visible satellite imagery and visual observations suggest attempts at in-situ initiation near Bismarck near the boundary too, and the minimal MLCIN sampled on our 00 UTC RAOB suggests storms may form the next 1-2 hours there, too. Storm-scale interactions/mergers and upscale growth may temper peak hazard magnitudes somewhat with this activity, if enough initiation occurs, but otherwise strong deep-layer shear favors large to possibly very large hail given moderate CAPE. Meanwhile, severe storms including a developing bowing complex in east central MT and a recently-developed supercell in southeastern MT near the surface low are all propagating toward ND. Dewpoints in the middle 60s F exist over a wide berth of western/central ND downstream of these storms, and very strong deep-layer shear will favor both supercells and bowing complexes, the latter of which is further favored by easterly low-level flow and related gust- front maintenance, large DCAPE, and increasing low-level shear. The one uncertainty with regard to how long-lived any bowing complex may be is how much convection develops ahead of it in southern ND in vicinity of the quasi-stationary boundary. If messy modes develop in the inflow region of the approaching bowing segment(s), then they may not be as long-lived, but if there is less opportunity for unfavorable storm-scale interactions, then a long-lived bow echo could impact western and into central ND. This is a subtle detail related to the coming event, but regardless, an increase in storm coverage and severe-storm risk is still anticipated the next several hours. Finally, note that there is a non-zero tornado risk with any of the storms in western and south central ND, especially as low-level shear and SRH increase toward and after sunset, but the potential for upscale-growing and/or messy storm modes may tend to limit that risk somewhat. UPDATE Issued at 605 PM CDT Sun Jul 3 2022 Moderate bouyancy with minimized MLCIN is present across southern and western ND late this afternoon owing to surface dewpoints in the middle to upper 60s F and steep midlevel lapse rates. A weak east-west-oriented boundary is in place across southern ND, but visible satellite imagery has shown little in the way of attempts at convective initiation in our forecast area the last 60 minutes. Larger-scale ascent approaching from both the west and south will likely serve as the impetus for increasing convective coverage and related severe-storm risks in the late evening in southwest and south central ND, as many CAMS including recent HRRR cycles have suggested. Moreover, extrapolation of the ongoing supercell- bowing complex transition near Jordan, MT, as of 23 UTC would have it reaching the ND/MT state line between before 02 UTC. Thus, we expect a rapid increase in severe storm risk in the mid to late evening over a wide portion of our forecast area. Where forecast considerations are concerned, we increased coverage and extent of 60-80 percent PoPs tonight with this update, and blended recent observed trends into the early evening hourly forecast elements. && .SHORT TERM...(This evening through Monday) Issued at 219 PM CDT Sun Jul 3 2022 Thunderstorm chances and the potential for severe storms highlight the short term forecast. Currently, an upper level low continues to spin over the far eastern Pacific with a broad southwest flow from much of California into the northern Rockies with an upper level ridge over the northern High Plains into the western Dakotas. At the surface, low pressure was situated over north central Wyoming with pressure falls onto southeast Montana and a warm front eastward through central South Dakota. Another stationary front was situated from the Northern Rockies eastward through northern North Dakota. A weak wave was moving over the apex of the upper ridge, producing showers over western North Dakota. North of the stationary more widespread showers extended from the Northern Rockies (where a shortwave was lifting northward into southern Alberta) east across northern Montana and into northwest ND. Surface pressures over the local area had been rising through most of the morning and have just began to slowly fall. A marginally unstable atmosphere with MLCAPE values of 1000-2000 J/KG over the southern half of the state will only continue to increase through the afternoon and into this evening. Deep layer shear remains strong across the forecast area. Late this afternoon into early this evening forecast soundings over central ND indicate little capping. The question is whether or not there is a trigger to initiate convection. Besides the numerous shortwave impulses propagating through the upper flow, a strong upper level jet moves over the area and strengthens tonight. We are thinking that the forcing from the right entrance region of the jet may be enough to initiate convection over south central into southeast North Dakota this evening. Some CAMS are indicating this, but there are still varying outcomes as to where/when and some do not develop convection there this evening. Another area of concern is western ND this evening. Beginning in the southwest early this evening as convection fires off the higher terrain of northern Wyoming and southeast Montana. Some of the CAMS have shown more discrete convection initiating here, which would increase the threat of large hail and possibly a tornado. The question for us would be whether or not storms, if initially discrete, continue that way as they move into southwestern ND. Or if they cluster or grow upscale before reaching the southwest, the hail threat would be smaller but with an increased wind threat. Finally, late tonight there is still a signal in some of CAMS of convection firing off the Rockies in central MT and making it into western North Dakota late this evening and progressing across the forecast area overnight. HREF UH neighborhood probabilities from 00 UTC and 12 UTC really drop off once they cross over into North Dakota, so hopefully the wind threat diminishes as advertised here. However the SPC Enhanced Risk does extend through much of the southwest. Here the mode would most likely be upscale with bowing segments by the time it reaches North Dakota, so the tornado threat would be lower, but significant winds would still be possible. With anomalously high PWATS, the location of the surface low and the weak upper level flow and a stationary front draped over the forecast area, we will continue to message the potential for localized flooding due to very heavy rain with thunderstorms that develop. There is enough uncertainty as to if storms develop and areal coverage south central and southeast this evening, as well as the progressive nature of convection moving into the west late, to hold off on a flood watch. But given we may see a few rounds and the late timing for the last round, can not completely rule out a watch this evening. Monday morning we may still be dealing with lingering convection overnight tonight, but this should be non-severe by then. There are some differences in the medium range models, but in general we get a period of cooler northerly flow on Monday, with probably some widespread low ceilings through the morning. It`s then a question as to how things clear out Monday afternoon and if we can destabilize enough again for another chance of strong to severe storms, as there is another decent shortwave moving through the forecast area. At this time CAMS that go out that far vary from little or nothing, to strong to severe storms central and east. Oh and possibly storms moving into the west late. I think it`s best to revisit this again after tonight. .LONG TERM...(Monday night through Sunday) Issued at 219 PM CDT Sun Jul 3 2022 Thunderstorm chances continue nearly each day through the long term period, with the possibility of severe weather. Warmer temperatures are expected toward the end of the period. Surface high pressure over Canada continues to drop south into the forecast area Monday night. Instability continues to trend farther south, with the south and west being the better areas to see enough instability for overnight thunderstorms Monday night. On Tuesday the cooler surface high slides east and we begin a period of broad upper level ridging over the area, but with a continued barrage of shortwaves through the mean ridge position. This will bring warming temperatures mid to late week with on and off thunderstorm chances. Our recent strong bulk shear does drop off a bit but instability will not be lacking, so mostly diurnally driven thunderstorm chances remain in the forecast each day, but with a lot of uncertainty in timing. placement and coverage each day. The western trough does eject into the Northern Plains by the end of the forecast period, perhaps bringing a better chance of more widespread thunderstorms next weekend. The upper low mentioned in the short term discussion moves onto the Pacific Northwest coast on Monday with downstream ridging situated over the western Dakotas. Upper level ridging continues to build over the area through mid week, lifting the Pacific Northwest upper low northeast through Alberta and into the central Canadian Prairie Provinces,and keeping a broad southwest flow over the local forecast area. Thereafter, we may see a day or so of zonal upper flow before another western Pacific trough develops with downstream ridging over the Rockies and into the Plains states. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 935 PM CDT Sun Jul 3 2022 Scattered to numerous showers and thunderstorms will spread across most of western and central ND tonight. Local IFR conditions, large hail, and damaging winds are expected with the most intense storms. Showers and storms will diminish by 12 UTC, but there`s a high, ~60% probability of MVFR to IFR stratus developing across much of western and central ND late tonight into tomorrow. && .BIS WATCHES/WARNINGS/ADVISORIES... Flood Watch until 6 AM CDT /5 AM MDT/ Monday for NDZ045>048-050- 051. && $$ UPDATE...CJS SHORT TERM...TWH LONG TERM...TWH AVIATION...CJS
Area Forecast Discussion
National Weather Service Duluth MN
653 PM CDT Sun Jul 3 2022 .DISCUSSION...(This evening through Saturday) Issued at 348 PM CDT Sun Jul 3 2022 Summary: Active pattern continues this week with several opportunities for showers and thunderstorms. A few storms tonight and Monday may be severe. Temperatures gradually warm up during the week. A surface warm front stretched from near Grafton, ND to Bemidji, MN to a little north of Moose Lake to near Manitowish Waters, WI as of 19Z. A 20-25 kt southerly low-level jet was located over central Minnesota per RAP analysis at 19Z. The LLJ will continue to trek northeastward this evening and strengthens to 25-30 kts by 06Z. There has been enough convergence along the northern periphery of the LLJ to keep showers and a few thunderstorms percolating over central, east-central, and north-central Minnesota into northwest Wisconsin this morning into early afternoon. GOES-East water vapor imagery reveals an anti- cyclonically curved jet streak and shortwave trough over the eastern Dakotas and western Minnsota. Persistent convection in eastern South Dakota into western Minnesota is in the right entrance region of the jet streak. Convective parameters are not impressive at this time. Weak 0-1km MLCAPE of 250 J/kg was found over most of the Northland. Abundant cloud cover has limited destabilization this afternoon. A slight increase in instability is expected over portions of central and north-central Minnesota by this evening into the 500-1000 J/kg range. Deep layer shear is sufficient for storm organization and areas where strong storms are most likely feature cyclonically curved hodographs. If a few storms can tap into that stronger instability, a few damaging wind gusts and hail of penny- to half dollar-size are possible. In general look for precipitation coverage to continue to slowly increase into this evening as the jet streak and associated shortwave trough pushes farther eastward into the Upper Midwest. There is ample moisture available for heavy rain this evening through the overnight. Areas in central Minnesota east into the I-35 corridor have the greatest risk of excessive rainfall and flash flooding should storms repeatedly move over the same locations. Upstream over the Dakotas and eastern Montana, storms are expected to develop this afternoon and may coalesce into one or more eastward-propagating MCSes. If they persist, they will move into central Minnesota before 12Z Monday and may present a risk of damaging wind gusts in the Walker to Brainerd area and points west. Those storms will continue to propagate eastward Monday morning and will gradually weaken with time by late morning and early afternoon. A second warm front is forecast to lift into the Northland during the morning and afternoon hours Monday another round of strong to severe storms is possible along and south of the boundary. By late afternoon, MLCAPE along and south of the front will increase to 1000-2500 J/kg over central Minnesota east into northwest Wisconsin. Deep layer shear will be a little lower than this afternoon, but still sufficient for organized storms, 30-50 kts in the 0-6 km layer. Steep mid-level lapse rates of 7-7.5 C/km will support a large hail threat with storms that develop. Nearly straight hodographs suggest a potential for splitting storms. Working against the potential for severe storms is the persistent low-level jet and mid-level subsidence during the late morning and afternoon hours. The persistent jet may support widespread showers and storms throughout the morning, which would limit the destabilization and may also result in too many storms sharing the available instability. The subsidence may limit convection over central MN east into northwest WI through the afternoon, with the focus for convection over far northern Minnesota and northwest Ontario, where convergence is maximized and the timing of shortwave is more favorable. That area will see less instability, only 500-1000 J/kg. Many unknowns at this point and it seems prudent for people to plan ahead in case storms threaten tomorrow. Showers and storms may linger into Tuesday morning as the warm front pushes south as a cold front. Tuesday afternoon is shaping up dry with increasing sunshine expected. Rain and storm chances return as early as late Wednesday morning and will persist off and on through next weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 653 PM CDT Sun Jul 3 2022 Overall confidence with this set of TAFs is lower than average with poor model agreement. Confidence is higher over the next 6 hours, but drops beyond that. A complex of storms is expected to develop across the Northern High Plains tonight and track east Monday morning. There remains uncertainty on the timing and location of this complex and how strong it will be. The HRRR seems to be handling the current shower and storm activity, so leaned more heavily on it for the timing of the rainfall Monday morning. Most of the activity should push east of the region by early Monday afternoon, but may linger in spots. A period of IFR or lower CIGs will be possible Monday morning, especially where rainfall is received. VSBYs may drop to IFR or lower in heavier areas of rain. && .MARINE... Issued at 348 PM CDT Sun Jul 3 2022 A relaxed pressure gradient will persist over western Lake Superior early this week. Winds will generally be in the 5 to 15 knot range. There will be a few chances of showers and thunderstorms, and there`s a small chance some of the storms will be severe. The strongest storms will be capable of pea- to penny- size hail, wind gusts to 40 knots, frequent cloud-to-water lightning, and heavy rainfall which may reduce visibility to less than 1 mile at times. && .PRELIMINARY POINT TEMPS/POPS... DLH 53 67 53 70 / 80 70 50 10 INL 56 72 57 76 / 60 60 50 10 BRD 65 81 62 77 / 80 60 40 10 HYR 62 81 57 76 / 60 70 60 10 ASX 54 73 50 69 / 70 60 60 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ DISCUSSION...Huyck AVIATION...BJH MARINE...Huyck
Area Forecast Discussion
National Weather Service Grand Rapids MI
808 PM EDT Sun Jul 3 2022 LATEST UPDATE... Aviation .DISCUSSION...(This evening through next Sunday) Issued at 329 PM EDT Sun Jul 3 2022 - Independence Day Storms Late In The Day - My thinking has not changed from a few hours ago for Independence Day. I expect, with high confidence, that it will be dry most of the day. Precipitation would most likely enter far southwestern Lower Michigan after 7 PM and then spread east or southeast. Precipitation would be predominantly showers but some embedded thunderstorms are possible. A greater risk will be for heavy rain in the early morning hours Tuesday. This heavy rain threat will be greater west of US-131 and greatest near the Lake Michigan shore. Given the numerous activities scheduled for Independence Day and the potential for convection here, it seems prudent to address our latest thinking on convection impacts for tomorrow. It seems there would be a convective complex moving across Iowa during the daytime, aided by a 40 knot low level jet aimed at western Iowa early in the day then more so towards eastern Iowa by late afternoon. This is the glitch for severe storms in Southwest Michigan tomorrow. Both the RAP model and NAM show the low level jet axis not crossing Lake Michigan until early Tuesday morning. When it does, after midnight, it points toward Holland. The 12z HREF agrees with the NAM and RAP models, both of those showing surface based, mixed layer and most unstable cape all remaining below 500 j/kg through midnight. Model soundings show narrow cape that`s typically located between 5000 and 10000 ft and that`s about it. Effective shear is forecast to be below 30 knots through midnight too. So, it would seem while showers are possible and perhaps even likely tomorrow evening, any threat for strong storms would be more likely during the day Tuesday. The more significant threat for our area is tomorrow night and it`s for heavy rainfall. There is good agreement with just about all of our high-resolution models for heavy rain (more than 2 inches in 6 hours) from near Holland, through Allegan to Kalamazoo. This includes the HREF, NAMNEST, FV3, WRF- ARW2 and Regional Canadian too. The NAM has it after midnight while the other models have it early in the evening. The 1000/850 moisture transport from the NAM and RAP do look impressive for heavy rainfall for Independence Day evening. Having precipitable water values near 2" along and south of I-94 helps the cause for heavy rain. Precipitable water values that high are over 2 standard deviations from normal and near record values for early July (or any time of the year actually). - Some threat for convection continues into Tuesday afternoon - Since the front will be slow to move south, and by mid morning Tuesday the instability near I-94 is well over 2000 j/kg and the the effective bulk shear is over 30 knots, it would seem convection will redevelop in the wake of the earlier or be triggered by outflow boundary interactions. This threat continues into the evening. - Quiet Wednesday then more convection Thursday/Friday The cold front finally slips south of the state by Wednesday. That should give us a quiet weather day then. Then the next jet streak from the Pacific tops the western ridge and comes into our area in the Thursday / Friday time frame. That will bring warmer and more humid air once again with the threat of more thunderstorms. It is possible through that the deepening eastern trough may become large enough that the convection for Thursday and Friday may stay south of here. Once that system clears the area and classic summer weekend looks in store for Southwest Michigan with little threat for rain, afternoon temperatures in the 80s and low afternoon humidity. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 808 PM EDT Sun Jul 3 2022 VFR conditions are in place across Lower Michigan at 00Z and this should remain the case much of the next 24 hours. We will see some mid and high clouds stream into the area tonight, although bases will largely be at or above 10,000 feet. Clouds will begin to lower and thicken from the west late in the afternoon on Monday and especially into the evening hours. Cloud bases will remain VFR through 00Z, but we may see some ceilings around 5,000 feet developing after 21Z. Cannot rule out a few showers in the west on Monday afternoon and evening and have included some VCSH wording for now. Light winds tonight will become south Monday morning after 12z and increase to 10-20 knots in the afternoon. && .MARINE... Issued at 329 PM EDT Sun Jul 3 2022 The only real issue this week for our near shore area is thunderstorms later on Independence day into Tuesday afternoon. Those may result in large waves and gusty winds. More storms are possible in the Thursday/Friday time frame. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ DISCUSSION...WDM AVIATION...Duke MARINE...WDM
Area Forecast Discussion
National Weather Service Lincoln IL
819 PM CDT Sun Jul 3 2022 .SYNOPSIS... Issued at 650 PM CDT Sun Jul 3 2022 Mild and dry weather will prevail across central Illinois tonight with low temperatures dropping into the middle to upper 60s. Hotter and more humid conditions will develop for the 4th of July as afternoon highs top out in the lower 90s and heat index values exceed 100 degrees. Scattered thunderstorms will be possible as well...particularly along and north of the I-74 corridor. && .UPDATE... Issued at 819 PM CDT Sun Jul 3 2022 Clear skies are the rule across central Illinois this evening with 01z/8pm temperatures in the upper 70s and lower 80s. Convection is expected to develop well to the west across Nebraska/Kansas tonight: however, this activity will have no impact on the local weather as skies remain mostly clear through the night. Overnight lows will drop into the middle to upper 60s. Current forecast is on track and requires no major changes at this time. && .SHORT TERM...(This evening through Monday) ISSUED AT 320 PM CDT Sun Jul 3 2022 The center of the surface high influencing central Illinois weather this afternoon is now over southern Michigan, with a weak northeasterly pressure gradient leading to east-southeast winds with a few gusts up around 20 mph. Dew points continue mostly in the upper 50s to lower 60s with higher moisture values farther south over southeastern Missouri and southern Illinois. From this afternoon through tomorrow, at mid levels a 500 mb ridge axis will maintain a position to the west of Illinois near the eastern Dakotas/eastern NE. Difference continue to exist in convective evolution over central Illinois from CAM forecasts for Monday. In general, expect increasing convective coverage over KS/NE late this evening, moving eastward and crossing IA during the early morning hours. From there, solutions diverge with the majority limiting activity to the far northern fringes/north of the ILX CWA during the afternoon on Monday with perhaps some outflow winds moving southward. However, one or two solutions (including the HRRR) depict a more linear-like feature moving from west to east through the CWA during the afternoon and early evening. Around 1000-2000 J/kg of MLCAPE and 20-30 kt of 0-6 km shear will support storm severity and organization, though the lower-end shear could be a bit of a limiting factor. SPC slight risk in the northern portion of the CWA with risk decreasing with southward extent characterizes the current probabilities well. Depending on the southward extent of tomorrow`s convection and outflow, the combination of heat and humidity may be a concern as well as moist air is pulled back northward/eastward. The current forecast has heat indices nearing 105 degrees near and south of a line from Rushville to Olney. A heat advisory has been issued for our southernmost counties, which will likely need to be expanded into at least a portion of the forecast area for Tuesday and/or Wednesday. .LONG TERM...(Monday night through Sunday) ISSUED AT 320 PM CDT Sun Jul 3 2022 Forecast concerns for the Monday night through Sunday time frame center around the following: 1) Extent of and duration of high heat indices through this week, given the warm/humid air mass south of a frontal boundary and uncertainties in frontal location/convective evolution 2) Given this week`s pattern and the rainfall deficit in much of central Illinois, assessing opportunities for rainfall and/or thunderstorms It`s hard to separate the above two concerns as they are related. On Monday night, CAMs in general show initiation of a storm complex to our north with some uncertainty in whether that complex moves southward into the ILX forecast area as it weakens on Tuesday morning, or heads farther east. This could impact 1) temperatures on Tuesday depending on outflow generated Tuesday morning and 2) rain chances especially north of I-72/Danville. Though high temperatures ultimately could be a hair cooler if rainfall and outflow reach the CWA Tuesday morning, humidity will be increased as well. At this point, even in this scenario Tuesday would likely be the day with the highest heat indices of the week. On Tuesday night, deterministic guidance indicates a setup which would once again support development of a storm complex to our north, with another chance of making it into the ILX forecast area as it weakens Wednesday morning. In addition, the frontal boundary is forecast to move farther into central Illinois on Wednesday. The southward movement of that boundary will be one factor in determining what locations might be in the hot/humid air and still needing a heat advisory on Wednesday. The frontal boundary will remain in the vicinity on Thursday and Friday as shower/thunderstorm chances persist. Temperatures are forecast to cool somewhat with rain chances decreasing into the weekend as the ridge strengthens over the central Rockies and the flow turns more northerly over the Midwest. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 650 PM CDT Sun Jul 3 2022 Main aviation forecast challenge will be potential convective development on Monday. Short-range models show a variety of solutions, so overall confidence remains low. General consensus suggests a cluster or line of thunderstorms will track across northern Illinois on Monday, with scattered storms developing further south along an outflow boundary left behind by the main storm complex. Have followed the 18z HRRR closely for this forecast...introducing a 3-4 hour window of VCTS beginning at 18z at KPIA, then at 22z further east at KCMI. Winds will initially be SE at less than 10kt tonight, then will veer to S and increase to 10-15kt on Monday. && .ILX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 2 PM Monday to 11 PM CDT Wednesday for ILZ040- 047-049>052-061-066-071-072. && $$ UPDATE...Barnes SYNOPSIS...Barnes SHORT TERM...AAT LONG TERM...AAT AVIATION...Barnes
Area Forecast Discussion
National Weather Service North Platte NE
624 PM CDT Sun Jul 3 2022 .SYNOPSIS... Issued at 331 PM CDT Sun Jul 3 2022 H5 analysis this morning had high pressure anchored over the southeastern CONUS. Low pressure was located over northern Quebec with a second low noted off the coast of Washington State. Southwesterly flow aloft extended from southern California northeast into the central and northern Rockies. Zonal flow was noted from the Dakotas and northern Nebraska east to the Mid-Atlantic. Within the southwesterly flow aloft, shortwaves were noted over western and central Montana, along with a decent shortwave over southern Colorado. Stilt imagery from late morning indicated a weak meso- vort over west central Kansas. Northeast of this feature, a shield of stratus was present over central into eastern Nebraska. Dew points in this area of stratus were generally around 70 degrees as of 11 AM CT. Shifting to this afternoon, the stratus field had shrunk to eastern Nebraska. Southerly winds and hot temperatures had replaced this feature with readings ranging from around 90 degrees in northern Nebraska, to the upper 90s in southwestern Nebraska. && .SHORT TERM...(This evening through Monday night) Issued at 331 PM CDT Sun Jul 3 2022 The main forecast challenges in the near term are thunderstorm chances tonight and Monday night along with the heat on Independence Day. For tonight, the latest CAMS and Nam soln develop some convection this evening across the forecast area. With this morning`s runs, there are two schools of thought when comparing the NAM soln to the HRRR solns this morning. The NAM12 and NAMNest solns develop two rounds of convection. The first is over southwestern Nebraska INVOF the differential heating boundary which was a result of the eroding stratus field from earlier today in South Central and Central Nebraska. The second is in the form of a line which develops later this evening and conjeal`s into a mcv across central into northern Nebraska overnight. With the second mode, we already have some convection beginning to form over eastern Wyoming ATTM so this seems plausible and feel fairly confident in this carrying east into our forecast area later this evening. With respect to convection developing over SW Nebraska, this is more up in the air, however, with some agitated CU development around MCK over the past hour, this seems plausible as well. With this in mind, will paint pops early on in the SW and west, then carry this eastward into the overnight hours. As for severe mode, hail is a threat in SW Nebraska early on, as mid level CAPE`s reach 1500+J/KG through early evening. Very large hail however doesn`t seem like a threat ATTM given the weak mid level winds H500-H700 and marginal 30 KTS of deep layer shear. The severe mode transitions more to a wind threat later this evening as a robust 35 to 50 KT low level jet develops from south central into central Nebraska. With the expected development tracking east into central and north central Nebraska later this evening, any storms which can become anchored on the jet have a decent chance to produce some gusty winds. On Monday, a weak frontal boundary will sag south into far northwestern Nebraska. South of the front, temps will reach well into the mid to upper 90s, with some readings reaching around 100 degrees in SWrn into central Nebraska. With dew points in the lower to middle 60s Monday afternoon, resultant heat indexes will reach 100 to 105 degrees generally along and east of a line from Valentine to North Platte to Hayes Center. That being said, decided to hoist a heat advisory for these areas from 1 PM To 8 PM CT Monday. There will be a more limited threat for thunderstorms Monday afternoon into Monday evening across the area. With the front expected to be draped over the northwestern forecast area Monday afternoon, there is a surface focus for convective development. However, SB CAPES are very meager Monday afternoon. In fact the best CAPE is north of the forecast area over southern South Dakota. However, with the expected surface boundary in place, went ahead and included some low pops across the northern half of the forecast area Monday evening. .LONG TERM...(Tuesday through Sunday) Issued at 331 PM CDT Sun Jul 3 2022 The before mentioned front will stall across the forecast area Tuesday. South of this feature, heat indexes will once again top 100 degrees. This will ultimately lead to the need for a heat advisory somewhere in the southern forecast area. There is still some doubt as to where this front will reside given the expected convection today and possible convection Monday afternoon. That being said, decided to hold off on issuing a heat headline for Tuesday afternoon. As for the threat for storms, it appears better on Tuesday afternoon/evening. Available CAPE is much better on Tuesday afternoon with SB CAPES of 2000-4000 J/KG across the area. Deep layer shear is more robust as well on the order of 30- 40 KTS which will be more favorable for severe storms compared to Monday`s setup. The threat for afternoon and evening thunderstorms will continue Wednesday and Thursday as the persistent trough remains off the coast of the Pacific NW states. This feature will lift into western Canada late in the week, allowing the ridge across the SE CONUS to build northwest into the southern and central Plains. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 624 PM CDT Sun Jul 3 2022 Scattered thunderstorms are expected throughout wrn and ncntl Nebraska this evening through 09z Monday morning. No thunderstorms are expected thereafter through Monday afternoon. There is a chance, about 30 percent, sporadic MVFR ceilings will develop Monday morning, generally affecting areas along and east of highway 61 and south of highway 20 between 09z and 15z. && .LBF WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 1 PM CDT /noon MDT/ to 8 PM CDT /7 PM MDT/ Monday for NEZ005>010-025>029-037-038-059-070-071. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...CDC
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
753 PM CDT Sun Jul 3 2022 .UPDATE... Issued at 753 PM CDT Sun Jul 3 2022 It`s a beautiful evening with light winds, mostly sunny skies. and temperatures in the lower 80s. National satellite imagery depicts numerous areas of convection stretching from western Montana to southern New Mexico, the Dakotas, Southern Plains, Ozarks, and mid-Atlantic. The Great Lakes and northeastern United States are just about the only parts of the country east of the Rocky Mountains enjoying a pleasant, storm-free evening. Our luck appears to be running out however, as chances for storms look to increase tomorrow and last through the end of the week. It`s tough to add more value to the going forecast for tomorrow given the convection upon which it is reliant is only now becoming organized well to our west. It remains probable that some remnant form of thunderstorms or a convectively-invigorated upper-level shortwave trough from overnight will track into the western Great Lakes tomorrow afternoon and present a chance for at least scattered thunderstorms across our area. We remain (cautiously) optimistic there will be a break before additional, likely more vigorous, thunderstorms develop after dark and parade through the night. In these scenarios, it`s tough to pinpoint where new thunderstorms will develop given a dependence on so many factors in the 12-24 hours beforehand. Recent high resolution guidance offers placements ranging from southern Wisconsin to southern Lower Michigan northeastern Illinois. We anticipate spread to remain in the upcoming suite of 00Z guidance. At any rate, wherever the 2nd round develops, severe weather and flash flooding threats will no doubt make their presence known given increasingly "fat" CAPE profiles and PWATs climbing (well?) above 2 inches. For now, we`ll enjoy our last quiet evening for a while in anticipation of our upcoming stormy stretch. Borchardt && .SHORT TERM... Issued at 152 PM CDT Sun Jul 3 2022 Through Tonight... A rather extensive cu field has developed on the lake breeze this afternoon, with sunny skies near the lake. Some of the short term/ high res guidance has been occasionally developing a shower on the lake breeze through mid/late afternoon. Confidence is very low but an isolated shower or some sprinkles are possible through late afternoon, with the lake breeze, across northeast IL. This cloud cover will dissipate early this evening with increasing high/mid level cloud cover overnight into the predawn hours. Low temps will drop into the lower/mid 60s for most of the area, with upper 60s/lower 70s for the immediate Chicago metro area. cms && .LONG TERM... Issued at 259 PM CDT Sun Jul 3 2022 Monday through Sunday... This Independence Day will feature unsettled weather in the region with a hot and humid air mass impinging and the likelihood of some thunderstorms. The character and timing of these thunderstorms for the last few days has been of lower confidence, though certainty on how this will pan out is starting to inch higher for the daytime and early evening, before confidence drops into the night through Tuesday. Key messages are: * Increasingly more humid by the 4th of July evening, then hot and humid Tuesday * A swath of scattered showers and storms moving east over the area during the afternoon of the 4th; fairly low severe chances (level 1 of 5) with this * Potential for organized thunderstorms to develop over/near southern Wisconsin in the evening and track southeastward into the area; low confidence on the size, timing, and track of such a complex but some severe threat with this (level 2 of 5) * Heavy rain and some flood threat with late evening and overnight activity especially if it were to materialize and backbuild The broad and still somewhat flat upper ridge will have expanded across the nation`s midsection to start the 4th. The mid level short wave of interest for afternoon activity is backtracked in model solutions to eastern Colorado at present, and while nothing stands out on current satellite water vapor imagery, guidance of various resolutions is in solid agreement of this. This feature and an associated 40 kt 700 mb speed max will ride atop the ridge while possibly having convective enhancement over Iowa early on the 4th, before tracking eastward into/near northern Illinois during the afternoon. This will at the leading edge of broader warm advection aloft and a sharp gradient of tropospheric moisture (PWATs) and instability (MUCAPE). All of this supports an area of scattered showers and some convection, though how compact this is is tough to decipher. But there should be a 3-4 hour window of increased shower and some thunderstorm chances, probably greater north of I-80 given the vort track. Instability and even shear are expected to gradually increase, so some stronger storms may evolve after 4 PM from west to east, especially if this wave is more convectively-enhanced with greater shear. The expected cloud cover during the afternoon (also thicker north of I-80), should retard temperatures from warming too significantly. Those locations seeing rain will likely drop several degrees too. South of I-80 and maybe into Chicago has the best chance of hitting 90 early in the afternoon before any slight cooling. Dew points will be rising through the 60s and to 70 by late afternoon, and this is well agreed upon in guidance. While the above is the part of the forecast where confidence has increased the most, in the evening time of many outdoor festivities the confidence remains on the lower side. Conceptually a drop in coverage behind the mid-late afternoon activity would be expected in such a setup, however there is not a strong cap building in and there is the likelihood of an additional short wave further north tracking across the Upper Midwest. This will have the likelihood of interacting with the surface warm/stationary front where more heating had occurred near the border region of Minnesota-Wisconsin-Iowa for convective initiation in the early evening. This idea at least has the backing of a large majority of both global and high-resolution / convection allowing models (although the HRRR shows little development in the area). So have leaned the forecast a little more in this direction, with PoPs increasing in the north in the early-mid evening, and then quickly increasing late evening into overnight from north to south. This timing will be close to impacting outdoor evening festivities, especially in the northern CWA, though given the air mass that will have expanded into the area, nowhere is free of evening thunder chances. Regarding storms during the late evening into overnight, the instability/moisture/shear spectrum space upstream would support potentially rapid growth and upscale organization. The low-level jet is forecast at 45 kt and unimpeded into southern Wisconsin, so that conceptually supports the idea of good moisture replenishment as well as potentially a zone of regenerating and backbuilding convection on the western/ southwestern portion of any MCS. The 12Z HREF mean of its members depicts 1.5-2 inches of rain for along/north of I-90, and that`s a decent heavy rain signal for >24 hours out. The forward propagation MCS area (if one does develop) would be on the eastern/southeastern side would have the chance for at least embedded severe winds. This does not scream a rapidly propogating feature, but most models do show deep layer shear greater than 30 kt north of I-80 and ample features for cold pool organization with deep cores on the leading edge. For Tuesday, much may be impacted by what occurs Monday night, as it typical with the "domino effect" of being on the northern periphery of a heat dome. Synoptically, there`s support for building heights during the first half of Tuesday, which would likely minimize convection, however the front/outflow composite will be either in or near the CWA, with signatures of a backdoor push off the lake. A lack of capping with this setup would support afternoon convection along the wind convergent areas. Signs of short wave energy passing over the Corn Belt region increase late Tuesday into Tuesday night. Overall, not enough to change much from "chance of showers and thunderstorms" at this point. Mixed-layer CAPE looks to be above 2,500 J/kg and non- weak (25-35 kt) mid-level flow would support scattered severe potential, if convection can fire. Tuesday temperatures will also have some modulation from any convection or convective effects, including from late Monday night. But either way it looks hot and humid. Flow does look to turn off the lake for the Chicago metro and far northwest Indiana, but that may not happen until later in the afternoon. With dew points solidly in the 70s, heat index readings well away from the lake very well could top 105F and require a Heat Advisory. MTF [Wednesday through Sunday] Wednesday and beyond, there does look to be potentially several more convectively enhanced vort traversing the general region. Timing and placement details of these features will have huge impacts on precip chances and amounts as well as temperatures as MCS activity will undoubtedly play a big role in the location of the effective boundary. Near and south of the boundary, air mass will be very humid and hot, with heat indices over 100F a good bet. That boundary could easily lift north into or even north of our CWA at times, bringing heat and humidity to the region. It`s not uncommon for the effective boundary ends up being farther south than some of the model guidance suggests in active ring of fire regimes as convective cold pools shove the effective boundary southward. Given the high degree of uncertainty in the forecast, saw no reason to stray from NBM through the period. There very well could be two or three bouts of heavy rainfall and/or severe weather, but an examination of the individual GEFS and EPS (ECMWF) ensemble members still shows a plausible scenario that there very well could be areas that end up with not much additional precip. This being said, noted on the 12z cycle a stronger signal for a much more active Friday-Friday evening than some of the previous runs. All in all, it`s all going to be a matter of where these convective clusters/complexes track and if your particular garden, lawn, or crops end up on the receiving end of the precip or end up being one of the potential have-nots. Also important to note that while the forecast will show precip chances every day and night through the upcoming week, there will be extended periods of time with no precip and that the week will not be a total wash out. By the weekend, some amplification of troughing east and northeast of the Great Lakes and further amplification of the intense heat ridge out west (ie. 600 DM at 500 mb over the Rockies on the 12z ECMWF) could/should allow Canadian high pressure to build south resulting in less humid air and far lower precip chances by Saturday and Sunday. Temperatures will be seasonably warm inland and cooler lakeside due to persistent onshore winds. Castro/Izzi && .AVIATION... For the 00Z TAFs... Aviation Forecast Concerns: * A couple of rounds of organized thunderstorms are possible later in the forecast period. The first Monday afternoon, and then another later Monday evening/overnight. In the near term, all is quiet across the forecast area with fine VFR aviation weather this evening. Surface high pressure was centered across the northern and central Great Lakes providing generally light southeast winds across the region. Slightly stronger and more easterly wind component associated with lake breezes off of Lake Michigan will diminish quickly this evening. Winds turn southerly Monday morning with some potential for gusts into the 15-20 kt range during the day, though thickening high cloud cover may temper gusts a bit. Of greater concern will be an area of showers and thunderstorms which is expected to move into the area from the west during the early-mid afternoon hours in association with a warm front, and a mid-level disturbance currently emerging from the central Rockies. Various CAM guidance is in relatively decent agreement in depicting storms moving into the KRFD area 19-20Z, and into the Chicago metro terminals in the 20-22Z time frame. These should propagate east of Chicago around 00Z, though a more humid and unstable air mass spreads in behind these heading into Monday night. A strengthening low level jet is expected to regenerate thunderstorms across parts of eastern IA/WI/LM along/north of the surface warm front which lifts across the area in the afternoon. Several CAMs (3km NAM, NSSL WRF, RAP, FV3) indicate storms develop northwest of the area across parts of southern WI early Monday evening, then spreading southeast across northern IL and the terminals during the late evening/early overnight hours. While some timing differences exist, did include a prob30 from 04-06Z for ORD and MDW to show the trend into the overnight particularly with the potential for these storms to be strong to severe. Ratzer && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
900 PM PDT Sun Jul 3 2022 .SYNOPSIS...A weak upper level trough over the region will maintain near to slightly below average temperatures for much of this week with morning clouds followed by afternoon sunshine each day. Chances for showers continue through at least Wednesday. && .SHORT TERM /THROUGH TUESDAY/...Cool low levels beneath a cold core upper low off the coast coupled with warmth east of the Cascades is driving the weak onshore flow. A similar trend of strong onshore flow aloft is expected tonight which likely will bring a return of the marine stratus...although possibly not nearly as deep as what occurred last night. Forecast soundings from the NAM and HRRR suggest that winds beneath roughly 5000 ft (850 mb) will become virtually absent tonight, and that the boundary layer will be saturated from the surface up only to around a half kilometer. So with its lack of depth will lead to less cloud cover and minimal (if any) drizzle relative to what the area experienced this morning. The best chance for it will be along the north Oregon coast, where a slight chance was added to the forecast. Aside from those few showers (which are most likely in the south Valley and Cascades) early in the morning, Monday will be dry until the late afternoon when scattered showers are expected to move north-northeast into the area from southern Oregon ahead of another lobe of upper level low pressure rotating into the PacNW. Forecast soundings continue to advertise a stable layer around 500-600 mb, so thunderstorms Monday evening/night continue to appear unlikely for any part of the CWA. Another round of showers will be likely on Tuesday, with the overwhelming majority of members within the EPS depicting QPF in our area. There are once again some hints that instability may be sufficient for thunder in the Lane and Linn County Cascades Tuesday. Both NBM and SREF suggesting 20+% probabilities for thunder along and near the crest, and forecast soundings from the NAM again suggesting more than 500 J/kg of MUCAPE. It appears that flow within the unstable layer below roughly 500 mb will have a large enough westerly component that cells will be driven quickly east of the crest, but before that time a strike or two seems reasonable. Thus, a slight (i.e., 20%) chance for thunder has been added to the forecast for those areas; this means that lightning is possible with convection, though chances for not hearing thunder are 4 times greater. -Muessle/Bumgardner .LONG TERM.../WEDNESDAY THROUGH SATURDAY/...WPC`s cluster analysis page forecasts generally less than a 75 dam difference in 500 hPa height between the coolest and warmest clusters throughout the extended, indicating ensemble agreement in the medium range is high. Through at least Thursday, the upper low dominating our weather in the short term is most likely to remain just west of us over the eastern Pacific, maintaining near to slightly cooler-than-normal temperatures and transient but frequent chances for precipitation amidst south- southwesterly mid level flow. NBM has maintained its chances for thunderstorms in the Cascades for Wednesday and Thursday, and forecast soundings display some instability supportive of this potential. Thus, no major changes have been made to the forecast for areas with slight chance mentions for thunder. Wednesday continues to look like the day with the most expansive thunder threat throughout the Cascades as it is the day with the least westerly component to the low and mid level flow (and hence storms that develop in the high terrain will not be quickly driven east of our area, but will rather ride northward along the mountains). Uncertainty in whether the low dissipates and the PacNW is overtaken by the ridge to our east becomes apparent next weekend, when the temperature and precipitation forecasts become a little less clear. Currently the NBM`s prediction for both was not touched during that time period, when chances for precipitation appear highest in the Cascades, and temperatures are forecast to climb into the mid 70s to low 80s in the Willamette Valley - near to just below climatology. -Bumgardner && .AVIATION...06Z TAFs: An upper low pressure near the Oregon coast will drift northeast tonight and into Washington on Monday. Will see variable mid to high clouds passing across the area with a chance of lower marine stratus overnight. Latest model guidance suggests onshore flow weakens tonight before strengthening again by Monday afternoon. Model guidance has also backed off on widespread MVFR developing again overnight, but will keep a mention of a few hours of possible MVFR conditions between 10-14Z Monday, although cigs will most likely be around 3500-5000 feet. One exception may be near the north Oregon coast, where more frequent MVFR expected at KAST. Skies should then scatter out by afternoon with predominately VFR conditions expected. For detailed Pac NW aviation weather information, go online to: KPDX AND APPROACHES...Predominately VFR expected tonight and Monday. Will see mid level clouds move north across the region while lower marine stratus attempt to redevelop around 12-16Z Monday. May experience brief MVFR but cigs most likely around 4000-5000 feet. Light northwest wind through the period. -DH && .MARINE... Weak surface high pressure remains over the coastal waters, while upper low pressure remains off the west central Oregon coast. Pressure gradients not all that strong, keeping winds 5 to 15 kt into Tue. Seas not all that much, running 2 to 4 ft. But, will have a mix of swell fetches over next few days. Primary swell is west swell 2 to 3 ft at 10 seconds, with a secondary swell running 1 to 2 ft at 15 seconds. -Rockey For information about upcoming marine zone changes, go online to: && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ Interact with us via social media:
Area Forecast Discussion
National Weather Service Pueblo CO
324 PM MDT Sun Jul 3 2022 .SHORT TERM...(This evening through Monday) Issued at 320 PM MDT Sun Jul 3 2022 Key messages: 1. Scattered to numerous thunderstorms expected into this evening, main risks will be lightning and locally heavy rainfall. 2. No change in the weather pattern for Monday, with widespread afternoon/evening storms over the mountains, scattered to isolated coverage elsewhere. Another round of afternoon/evening convection across the area today, though storms look a little weaker than yesterday, perhaps due to lee surface trough on the plains and subsequent wly downslope flow along the I-25 corridor behind it. Low shear (0-6km values of 20 kts or less) also playing a role in keeping storms relatively weak, though one or two cells could become strong/low end severe in the more unstable air and better wind regime east of the lee trough on the plains and along the Palmer Divide. Again expect main risk with convection into the evening will be locally heavy rainfall, especially with some training/redevelopment along weak boundary from Trinidad to La Junta. Expect most activity to fade away toward sunset, though latest HRRR does drag some convection off the mountains into the Interstate 25 corridor 9-11 pm. May also see some showers linger back over the southwest mountains into Monday morning, as deeper moisture lingers through the night. On Monday, not seeing much change to the upper level or surface pattern across the area, with continued feed of mid-level moisture in place while weak lee surface trough hangs out over the eastern plains. Expect convective coverage/strength to be similar to Sunday, with highest pops over the mountains, and least chance for storms over the far ern plains near the KS border. Little change in precipitable water, so again locally heavy rainfall the main storm threat. Max temps will continue a very slow upward climb over the plains, while mountains/valleys see little change. .LONG TERM...(Monday night through Sunday) Issued at 320 PM MDT Sun Jul 3 2022 Key messages: 1) Fourth of July evening, scattered PM thunderstorms for several locations may create another light show other than only fireworks for some. A few stronger storms could produce flash flooding in urbanized areas and over burn scars. 2) Widely scattered PM thunderstorms will be possible over the most areas from Tuesday through Thursday. PM storms will be more isolated for Friday through Sunday and mainly over mountains. Flash flooding will be possible, especially over burn scars and urban areas. 3) Temperatures will be warm on Tuesday, with a slight cooling trend Wednesday through Thursday, then becoming much warmer Friday through next weekend. Detailed discussion: Fourth of July evening... Latest HRRR shows a majority of the late evening thunderstorm activity on Monday being mainly over the I-25 corridor. The NAM 4km Nest keeps most of the convection confined more to the central portions of the I-25 corridor and along US-50 and just south. Analyzing the NAM12 lapse rates, steeper lapse rates appear to be over the Palmer Divide and the Raton Mesa. The model also shows a very high concentrated area of CAPE over the southern Sangre de Cristo Mountains of over 2000 J/kg in some areas. Given relatively higher shear of nearly 30kts as opposed to the surrounding areas, there could be a possible stronger or severe thunderstorm form just after 6 PM over this area and move out over the adjacent plains, possibly impacting locations such as Trinidad and Aguilar just before sunset, or right around the time for firework viewing. Some of the thunderstorms over the northern areas of the Sangre de Cristo Mountains, as well as the Wet Mountains, could also impact portions of the I-25 Corridor in Huerfano and Pueblo Counties. The Palmer Divide area looks like it could also be dealing with a thunderstorm right around sunset that will be moving into Lincoln County. Given the better shear and steeper lapse rates in this area, it is possible that a storm could become severe. However, soundings around this time for Colorado Springs reflect high LCLs with an inverted V signature, so the main threat would be gusty outflow winds to possibly 60 mph. With elevated cores above -20C, some hail will be possible, although CAPE appears to be only around 600-700 J/kg over most of El Paso County, so hail will likely not get bigger that pea size. The better potential of severe storms will exist further south over the southern Sangre de Cristo Mountains, where torrential rain could bring about flash flooding, especially over the burn scars. Hail potential will also be a bigger threat in this area, with possibly nickel size (or greater if storms become severe). As these storms move over into the adjacent plains and the southern I-25 corridor, there could be localized flash flooding in the urbanized areas. Storms could move out into the central and eastern plains, but should continue to weaken by midnight. Low temperatures for Monday night will be generally in the 60s for the plains, to the 40s and 50s for higher country. Tuesday through Thursday... Ensembles and deterministic models have been consistent for the past several days with the long wave pattern during this period in the forecast, showing troughing over the northwestern CONUS remaining nearly stationary and keeping the ridge over central CONUS. As the ridge overhead begins to flatten slightly, along with weak perturbations moving through in the longwave troughing upstream, the monsoonal moisture plume will shift back to being more over southeast Colorado, which will provide more widely scattered to numerous PM thunderstorms to develop over most areas of the CWA for Tuesday through Thursday. Tuesday will be quite warm, especially over the plains, under a stronger ridge. As troughing upstream helps to weaken the ridge and also allow for more moisture to move in over the region, there will be a slight cooldown from Wednesday through Thursday. With the enhancement of mid-level moisture over the mountains coupled with weak shear, there will continue to the the threat of storms remaining nearly stationary. This could result in potential flash flooding, especially over burn scar areas, for all 3 days during the afternoon and evening hours. Friday through Sunday... By Friday, as the ridge begins to build back again over the region and the upper level high over western Texas begins to slightly retrograde further back to the west, the moisture plume will also shift back to the west with a more north to south orientation of the ridge axis and keep any thunderstorm initiation confined to the mountains with a more northward mid-level flow. There will continue to be possible flash flooding concerns over the burn scars due to weaker mid level shear. Saturday will be very similar, with a slighter chance of thunderstorms over the plains and storms being more isolated over the mountains and confined mostly to the central mountains. Temperatures on Friday and Saturday will also be much warmer under the strengthening ridge with near 600 dm heights centered over western Colorado showing up on the ECMWF at the 500mb level on Friday. The GFS is now in better agreement with the ECMWF when it comes to the 500 mb heights being closer to 600 dm. The models tend to differ much more going into the weekend, with the ECMWF showing the ridge strengthening over the region and forcing an upper level low to become cut-off over northwest CONUS, whereas the GFS has the ridge flattening and troughing upstream beginning to push over the area on Sunday. If the ECMWF resolves this better, the monsoonal plume will remain more confined to the mountains with much drier and warmer temperatures for the plains. If the GFS resolves this better, the plume will be forced back to the southeast and allow for a better chance of thunderstorms over the plains with cooler temperatures overall. -Stewey && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 320 PM MDT Sun Jul 3 2022 VCTS risk at all terminals until 02z, with best chance of storms at KCOS and KALS. Wind and heavy rain/low visibility will be the main risk with storms, though some pea size hail is possible with the stronger storms. Activity ends 02z-04z, though a vcsh may linger through the night at KALS, as plentiful moisture remains over the area. Little change in the pattern Monday, with afternoon/evening convection once again after 20z-22z. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...STEWARD AVIATION...PETERSEN
...Update to aviation forecast discussion...

.DISCUSSION... Issued at 235 PM CDT Sun Jul 3 2022 19Z water vapor imagery shows broad mid level ridging over the southern plains and lower MS river valley while mid level troughing and a closed low affects the Pacific Northwest. This ridge over the southern plains is not pristine as an obvious vort max was noted over north TX where showers and storms have formed. But it is hard to see an obvious shortwave over the central high plains as the models have progged. At the surface, troughing along the lee of the Rockies has allowed a little more southerly wind to develop over the area and dewpoints have risen into the lower and middle 70s as a result. Hot weather continues to be in the main focus of the forecast beginning Monday and lasting at least through mid week. Across northeast and east central KS, the NBM shows little spread in the max and dewpoint temperatures leading to good confidence in the forecast heat indices. There is a little more uncertainty for parts of north central KS where dewpoint temps could mix out a little more. But the actual temperature is likely to remain close to the century mark. In addition to the afternoon temps, overnight lows do not look to provide much relief from the heat with min temps expected to only fall into the mid and upper 70s for a few hours. So with good confidence in the forecast during the first part of the week, have gone ahead and issued a heat advisory for much of the area beginning Monday afternoon through Wednesday evening. The NBM shows increasing uncertainty in temps after Wednesday so confidence is not high enough to consider an advisory beyond Wednesday. Nevertheless the forecast keeps the heat and humidity around through the end of the week and if confidence in the forecast increases, the advisory may need to be upgraded to a warning for parts of the area that see four or more days of advisory level heat. As for POPs, models continue to show what now looks like a convectively generate vort max lifting through southern NEB overnight. The GFS and RAP have trended further south with their QPF progs as inhibition increases tonight south of the state line. Am not sure I buy into this since mid level flow would tend to keep the vorticity north of the forecast area. So have kept some low end chance POPs across the far northern counties tonight in case convection builds south. Deep layer shear is very marginal across the forecast area tonight so it is uncertainty whether there could be severe storms. The main concern would be if an MCS develops and is capable of producing wind damage with a sustained cold pool. Have kept a dry forecast going for Monday, but the mid level vorticity over north TX is progged to move into northeast KS Monday afternoon and begin shearing out. 700MB level temps warm to about 13C with no obvious low level feature to focus convergence. With models including the CAMs failing to generate any precip through the afternoon, think chances are less than 20 percent but that is not to say something couldn`t pop up in the heat of the day. There are chance POPs in the forecast Tuesday night through Friday as models continue to suggest a weak boundary moving in from the west. It continues to look like Thursday or Friday stand the better chances as shortwave troughing weaken the mid level ridge. Unfortunately by the weekend models have the ridge redeveloping to the west of the forecast area. This is likely to keep the forecast dry with no relief from the heat and highs remaining in the mid and upper 90s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 606 PM CDT Sun Jul 3 2022 Short term concern is propagation of current convection to the south of TOP/FOE. Outflow is causing new storms to develop northward and this trend will continue through sunset so will include vicinity thunder in the forecast given it is uncertain how close this convection will get to TOP. Meanwhile, developing thunderstorms across central KS will move ENE and should stay northwest of the MHK site through 5z but needs to be monitored. LLWS may develop after 5z through sunrise around 2000ft. && .TOP WATCHES/WARNINGS/ADVISORIES... Heat Advisory from noon Monday to 9 PM CDT Wednesday for KSZ011- 012-021>024-026-034>040-054>056-058-059. Heat Advisory from noon Monday to 9 PM CDT Tuesday for KSZ008>010-020. && $$ DISCUSSION...Wolters AVIATION...Omitt
Area Forecast Discussion
National Weather Service Tucson AZ
200 PM MST Sun Jul 3 2022 .SYNOPSIS...Scattered showers and thunderstorms are expected through this evening and again on the 4th of July. Then Tuesday through Friday the storms should become more isolated and mainly limited to areas near the Mexico and New Mexico borders with afternoon temperatures gradually warming. Storm activity should gradually increase again next weekend. && .DISCUSSION...Storms started developing pretty much on cue late this morning and the HRRR seems to be doing well with the initial convection development. If that accuracy holds than the Tucson metro has a chance of a some showers/storms rolling through later today. For the 4th of July, we should have a little wave in the flow roll northward through the area although it may be a bit earlier than ideal if your looking for maximum affect. Multiple model solutions continue to suggest an upswing in activity tomorrow afternoon and evening and a little further west than today which makes sense given the scenario. Several of the CAM solutions indicate a group of storms rolling SE to NW through the Tucson metro later in the day tomorrow for more naturally generated fireworks. We will see! For Tuesday through Thursday and potentially Friday, we will see a gradual decrease in storm amount/coverage as the upper trough to the west lifts up and the upper level high begins trying to consolidate toward the west. This won`t be a shut down but storms will be fewer and primarily affecting far eastern and southern areas. With this kind of transition, afternoon temperatures will be on a gradual rise and at this time appear to peak Saturday around 3 degrees warmer than average. Ensemble/blend guidance then points to more moisture gradually returning to the area with temperatures slowly settling back. That said there is a fair amount of difference in various operational runs so the transition may not be as smooth as it looks at this time. && .AVIATION...Valid through 05/00Z. Through 04/05Z, SCT-BKN clouds at 7k-9k ft AGL and SCT SHRA/TSRA from a KTUS/KOLS line eastward. Slowly diminishing clouds and shower/storm activity aft 04/05Z. Erratic SFC wind gusts and outflows in excess of 40 kts possible with TSRA during the afternoon and evening hours. Somewhat more widespread showers and Thunderstorms expected Monday afternoon and evening. Otherwise, SFC wind generally less than 12 kts, favoring a SLY/SWLY direction during the afternoon hours and variable in direction at other times. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered showers and thunderstorms into this evening mainly from a Tucson to Nogales line eastward. Monday we should have a bit more storm coverage which should also expand to just west of a Tucson to Nogales line. Storm chances diminish Tuesday into Friday and become more confined to the New Mexico and Mexico border areas. Then starting next weekend, storm coverage should be on the increase again as the upper level high tries to settle into a more typical monsoon patter, 4-corners area. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Public...Cerniglia Aviation...Cerniglia Fire Weather....Cerniglia Visit us on Facebook...Twitter...YouTube...and at