Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/03/22

Area Forecast Discussion
National Weather Service Bismarck ND
951 PM CDT Sat Jul 2 2022 .UPDATE... Issued at 951 PM CDT Sat Jul 2 2022 An episodic severe-storm risk will continue until around 06 UTC, mainly focused over south central ND. A discrete and longer-lived supercell in southwestern ND will exit the state before 04 UTC, but the quasi-linear complex of storms west-northwest of Bismarck as of 0245 UTC will continue propagating southeast through an environment characterized by about 1000 J/kg of MLCAPE and deep- layer shear around 45 kt. MLCIN is increasing with time and will likely eventually lead to a gradual decrease in storm intensity, but established cold pools, favorable gust-front convergence with southeast low-level winds pointing into the convection, DCAPE on the order of 1000 J/kg and 0-3-km bulk shear around 25 kt sampled by the KBIS VWP will continue to favor possible damaging winds of 60-70 mph with the more intense line segments. Isolated severe hail also remains possible. This evolution is well-handled by recent HRRR simulations, so the hourly forecast fields were weighted toward its forecasts through about 07 UTC, but the overall theme of the forecast was relatively unchanged with this update. UPDATE Issued at 708 PM CDT Sat Jul 2 2022 Quick update to expand Severe Thunderstorm Watch 421 into central ND in collaboration with SPC, adding areas from Oliver and Mercer Counties north through McLean, Ward, and Renville Counties. This area contains a similar CAPE-shear setting as areas further west, so a severe-storm risk will continue with upscale-growing storms approaching central ND. Per collaboration with SPC, we will re- evaluate the need for a further-south expansion of the watch, perhaps into the Bismarck/Mandan area, later on since the storms will not reach that area for several more hours. We could need to extend the watch in time later on, too, and will continue to monitor and collaborate any future watch adjustments with SPC. UPDATE Issued at 552 PM CDT Sat Jul 2 2022 As of late afternoon, scattered intense storms which initiated in northeastern MT extend from near Crosby, ND, to the Glendive, MT, vicinity. As expected, an initially-discrete mode is occurring, and right-moving supercell motion vectors are only 10-15 kt, which has meant only slow propagation into ND. As gradual clustering and perhaps upscale growth occurs, increasing cold pools will tend to speed up convection by early evening, at least gradually, while it moves into and across western ND. The downstream environment is characterized by continued strong deep-layer shear on the order of 45 kt, favoring organized supercells and bowing segments, albeit with MLCAPE only around 1000 J/kg, which will likely restrict peak hazard magnitudes to an extent. Boundary layer moisture has been limited, and diurnal mixing has offset advection, especially over southwestern ND, but convection will gradually propagate into a region of slightly higher dewpoints near 55 F in west central ND this evening. Moreover, as mixing diminishes, low-level moisture advection may allow for higher- dewpoint air to reach the southwestern part of the state too, all suggesting that the risk of severe storms will increase after 00 UTC in west central and southwestern ND. Where the official forecast is concerned, only minor changes were made with this update, mainly blending observed trends into it. && .SHORT TERM...(This evening through Sunday) Issued at 200 PM CDT Sat Jul 2 2022 Thunderstorm Chances will be the main forecast issue in the short term period. Currently, surface low pressure is situated over central Montana with an inverted trough into southwest Saskatchewan. Meanwhile, an upper level trough continues to spin over the far eastern Pacific with downstream ridging over the northern and central High Plains. Numerous impulses will propagate through the mean ridge, setting the stage for periodic thunderstorm chances. Our first chances will be late this afternoon and this evening. Currently Steep lapse rates are situated over eastern MT, based on the 18Z GGW sounding. surface low pressure was situated just west of GGW and JDN MT with a weak surface trough. Strong bulk shear orientated across the boundary would initially support supercells. The main question is whether any supercells would sustain themselves long enough to move into western ND, where lapse rates are not as steep, but will become steeper as we go into the early evening. Also, it`s possible that upscale growth may occur by the time the storms reach ND, and this would lead to more clustering and increasing wind threat, but a diminishing hail threat. Our confidence in where/when upscale growth occurs, if at all is low at this time. Therefore we will continue to advertise hail to golfball size and wind to 60 mph. If the upscale growth does occur in ND, the wind threat would increase. HREF UH neighborhood progs >99.85 are favored over the far northwest late this afternoon and then slide southeast through the evening. HREF UH neighborhood progs >99.5 are nearly non-existent over the west and central tonight, meaning based on this, there would be less chance of a more high end severe wind event. However, there is a very low probability over the south central during the late evening hours, meaning that it can`t be completely ruled out. But right now confidence in this is very low. For the most part, it looks like the potential for severe weather, if not over, will be waning quickly by 06 UTC, but a lingering overnight shower/storm can not be ruled out overnight. Sunday will bring another chance of severe weather over the forecast area. Initially there could be some lingering morning convection over central ND. Increasing moisture from the south will spread north into the forecast area during the day with some mid and even upper 60s dewpoint possible, and thus producing more instability than we have today. There does look to be some lower level capping though. A few strong to severe storms can not be ruled out through the day, but most likely during the afternoon, especially south. The question will be, will there be a trigger to initiate convection. Our current NBM guidance is quite robust with pops across the area Sunday daytime. We pared these back a bit to get more of an isolated to scattered wording for convection Sunday. It appears that the main severe threat Sunday will be late, most likely late evening and overnight as convection over eastern Montana moves into western and eventually central ND. We have mentioned half dollar sized hail and 70 mph winds as the main threats on Saturday, but are messaging the potential for more of a wind threat with the late evening and overnight convection. .LONG TERM...(Sunday night through Saturday) Issued at 200 PM CDT Sat Jul 2 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. Initially, early Monday we may be dealing with ongoing convection exiting the eastern forecast area. More on this can be gathered from the short term discussion. The upper low mentioned in the short term discussion moves onto the Pacific Northwest coast on Monday with downstream ridging now 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 through mid week, keeping a broad southwest flow over the area through mid week. 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. Temperatures to begin the long term period are expected to be around normal or a little below normal Monday and Tuesday, depending on cloud cover and convective activity. Temperatures then warm to above normal late in the work week and into the upcoming weekend. Near daily chances of thunderstorms will remain in the forecast with mainly diurnally driven thunderstorm chances due to moderate afternoon and early evening instability with persistant moderate to strong deep layer shear. Predictability in daily location and timing of convection will remain high, but given the instability and shear, the potential for severe storms will probably remain each day of the extended period. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 951 PM CDT Sat Jul 2 2022 Showers and thunderstorms will continue moving through central and southwestern ND through about 06 UTC, with localized MVFR to IFR conditions, and potential damaging surface winds to 50 kt and large hail. This initial activity will gradually weaken after 06 UTC, but the chance of showers and thunderstorms will continue overnight and Sunday. MVFR ceilings may also develop Sunday as higher-dewpoint air moves into the area, but the chance of those lower ceilings developing and impacting any given terminal is only around 30 percent at this time. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CJS SHORT TERM...TWH LONG TERM...TWH AVIATION...CJS
Area Forecast Discussion
National Weather Service Duluth MN
1020 PM CDT Sat Jul 2 2022 .DISCUSSION...(This evening through Friday) Issued at 305 PM CDT Sat Jul 2 2022 Summary: A more active period is expected Sunday into next week with temperatures for most of the time a couple degrees either side of normal. Off lake winds will occur Sunday and Monday keeping lakeside areas cooler. A dry night is expected across the Northland with cool temperatures expected, especially over far northern Minnesota. Some patchy fog will be possible in spots as clear and calm conditions are expected. As high pressure slides east late tonight into Sunday, southerly low level flow will draw warmer temperatures and moisture north. Weak low amplitude shortwaves will move through the region and combine with the moisture/warm air advection to cause a chance for showers and storms across the Northland as early as late Sunday morning. Instability will increase through the day and favorable deep layer shear will be present. A few severe storms will be possible Sunday, especially late afternoon/overnight. Low level hodographs per the RAP showed plenty of curvature in the 0-3KM layer, especially in the evening/overnight when the low level jet increases as seen at 925MB. PWAT values are forecast to climb to 1.4 to near 2.0 inches Sunday night, highest values seen in the GFS. These values are in the 90th percentile with the 00Z NAEFS depicting values in the 99th percentile just south of our CWA. The low level jet, copious amounts of moisture, and a west to east frontal boundary south of the CWA will all support a threat of heavy rain Sunday night into Monday morning. Storm motions will be west to east and training of storms will be possible leading to heavy rain potential. Various models are showing some flavor of this with the HREF local probability match mean showing streaks of 2 to 4" of rainfall with pockets to 5" over or near the Northland. Predicting precise locations of the heaviest rainfall is not possible at this time but the potential for some heavy rain is there. The Monday morning showers and storms should decrease in coverage but they may not dissipate altogether or there could be redevelopment in the afternoon and evening as high PWAT`s will remain or be just south of the Northland. Confidence in how much development will occur late Monday into Monday night is lower than average. Those with outdoor plans should monitor the forecast closely. There will be periodic chances for more showers/storms through the week with an upper ridge over the central CONUS and a West Coast trough. Shortwaves will move through this ridge providing an impetus for storm development. There is some agreement that chances for precipitation Friday/Saturday will be lower and the best bet for a couple dry days. For now we have some low POPs and will refine them through the week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 628 PM CDT Sat Jul 2 2022 Initial VFR conditions are expected to continue through much of the TAF period. Fog is possible for some of the terminals overnight with light winds and clear skies, but have left out of terminals for now. Showers and thunderstorms are expected to move into the area after 15z, spreading southwest to northeast through the remainder of the TAF period. Have handled with VCTS groups for now until trends become better defined. Northwest winds will become light and variable overnight, then become southeast at up to 10kts after 15z. && .MARINE... Issued at 1020 PM CDT Sat Jul 2 2022 Sustained winds at or below 15 knots are expected for most areas through Monday although they may rise above that from Two Harbors to the Twin Ports to Port Wing Sunday into Monday. Winds will turn east to northeast Sunday and continue into the middle of next week. There will be a chance for thunderstorms Sunday afternoon into early next week. Some of the storms could be strong. && .PRELIMINARY POINT TEMPS/POPS... DLH 50 73 51 66 / 10 40 70 70 INL 43 77 57 73 / 10 40 50 40 BRD 54 80 64 80 / 10 40 80 60 HYR 49 81 64 79 / 10 50 70 80 ASX 48 78 53 72 / 0 40 70 80 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ DISCUSSION...Melde AVIATION...LE MARINE...LE
National Weather Service Hastings NE
643 PM CDT Sat Jul 2 2022 .UPDATE... Issued at 635 PM CDT Sat Jul 2 2022 Continued to keep chance of precipitation across the area low tonight as while an isolated thunderstorm may develop, the likelihood still remains pretty low. The main update is the increasing confidence in some low stratus and fog during the early morning hours Sunday based on the latest near-term model guidance. While pinpointing exactly where is nearly always an issue, there is increasing concern of patchy dense fog, particularly over areas that have received rainfall over the past few days. This will be something we keep an eye on overnight, especially with potential visibility reductions over highways and the interstate. && .DISCUSSION...(This evening through Saturday) Issued at 309 PM CDT Sat Jul 2 2022 High pressure aloft across the intermountain west will gradually shift east over the next couple of days...amplifying across the plains for much of next week. This will result in warmer weather returning to the local area...with widespread heat index values peaking above 100 both Monday and Tuesday. At the same time...multiple weak disturbances are forecast to impact the local area...with periodic small chances for thunderstorms each day. At this time...the two best chances for thunderstorms appear to be Sunday evening/night and then again Wednesday evening/night as a disturbance moves out of the desert southwest. For tonight...trimmed pops significantly across the local area as most models and the latest CAM runs are keeping us mainly storm free. Could there be an isolated storm or two...yes...but most areas will remain dry and any storms that develop should be short lived like the few showers we have seen here and there today. Of potentially greater significance is the potential for fog development overnight in favorable light southeasterly flow. SREF probs have a bullseye for visibilities less than 3 miles across the heart of the local area by Sunday morning and the latest HRRR runs are also indicating the potential for dense fog developing overnight. For the time added a patchy fog mention to the forecast are confidence in denser fog is not high...but this will be something for the evening shift to monitor tonight as the possibility is there. For Sunday...temperatures will begin their warming trend across the local area and the focus will shift to the better chance for thunderstorms returning to the local area by late afternoon or evening with a disturbance crossing the local area from the southwest. Latest NAM has backed off some on coverage for Sunday evening/night...but the 18Z NamNEST and HRRR both still have a fair amount of thunderstorm coverage. In addition...SPC has western areas in a slight risk for severe weather tomorrow night and the remainder of the area in a marginal risk for severe weather. Given the ample instability and a LLJ forecast to develop by mid/late evening...think that a few strong to severe thunderstorms will be possible with hail up to one inch in diameter and damaging wind gusts being the concerns. As we then transition into Monday...heat will become the main concern with heat index values exceeding 105 degrees in spots by late afternoon...which will likely eventually warrant a heat advisory for Monday. In addition...western areas will likely see near critical RH values during the afternoon hours along with the forecast breezy southerly winds...which combined will result in elevated fire weather concerns for areas primarily near and west of Highway 183. Thereafter...periodic small thunderstorm chances continue across the local area along with above normal temperatures...with the next best chance for more widespread thunderstorm activity looking like Wednesday evening/night as an upper level disturbance moves across the local area after exiting the desert southwest. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday) Issued at 635 PM CDT Sat Jul 2 2022 The TAF period will start with VFR conditions this evening, but visibility will likely diminish pretty dramatically to IFR or LIFR conditions during the early morning hours, especially at KEAR. Currently expecting around 2SM to 4SM VISBY with potentially LIFR CIGS for a few hours at KGRI and possibly VISBY less than 1SM for a time at KEAR with LIFR CIGS. Stratus should begin to dissipate with CIGS/VISBY improving by around 03/15Z, with VFR conditions returning by around 17Z or 18Z. Afterwards, in the afternoon, VFR conditions will prevail with southeast winds gusting to around 20 to 25 kts through the end of the TAF period. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...Hickford DISCUSSION...Rossi AVIATION...Hickford
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1008 PM CDT Sat Jul 2 2022 .UPDATE... Updated for evening discussion. && .DISCUSSION... Earlier rain from this evening`s round of showers and thunderstorms has nearly wound down. Some light rain may linger a little while longer. More concerning in the short term though, is the fact that a mid-level circulation remains centered over far southern Arkansas at this hour. With evening cirrus clearing out, satellite imagery shows a small area of cyclonic rotation in the mid-level clouds in that area. Analyzed PWAT values are near or or greater than 2.2 inches in the vicinity of this disturbance, and given the tropical nature of the atmosphere, the high res models` depiction of overnight convection intensifying near the low`s center seems reasonable. The latest HRRR shows increasing 850mb winds from a westerly direction around the south side of the low as we head to the early morning, with a resulting plume of showers and storms capable of producing several inches of rain where the axis sets up. Given some areas have seen spotty heavy rain through our ArkLaMiss Delta region over the last few days, the addition of a few inches of heavy rain overnight would pose a threat for some flash flooding. Have added a Limited threat area for Flash Flooding in the Delta for tonight, and we will continue to monitor this potential for heavy rain overnight. /NF/ Prior discussion below: Remnants of the tropical wave continue to produce brief rounds of heavy rain fall and on going thunderstorm activity across Arkansas and Louisiana this afternoon. While we expect rain and storms here across central MS much of that will be diurnally driven. We are however, under some moisture influence from the tropical wave which could increase rainfall amounts in a short period of time as storms start to develop. Scattered to numerous showers and thunderstorms (a few may become strong) will be the case through this evening. Storms should start to wane around sunset but a few lingering showers may persist tonight. Expect mostly cloudy skies with lows falling into the low 70s. Early tomorrow morning CAM guidance hints at redeveloping showers across the northwest. The main concern for that would be the potential for heavy rain fall. Current activity is mostly progressive so will hold off on any mention of flash flooding in the HWO for now and let the next forecast cycle shift assess later trends. If activity was slower, would be more prone to put something in the HWO this forecast but won`t for the reason just mentioned. Tomorrow will consist of another round of diurnal activity with possibly more widespread convection as the center of the disturbance moves closer to the region. Scattered to widespread showers and storms is expected. High temperatures will mostly be in the upper 80s. /JNE/ Sunday night through Friday night: The subtropical ridge is forecast to intensify over the lower MS Valley region next week, and this means that a typically hot July weather pattern will be in full force over the forecast area by the end of the long range period. Heat stress and diurnal shower and thunderstorm coverage will be the primary weather concerns, and while dry bulb temperatures don`t appear they will be especially hot, the stagnant airmass and recent wetter weather will result in increasing boundary layer RH. Heat indices should begin cranking up to the limited risk level Independence Day, and then to more dangerous levels as we go through mid to late week, so have continued to mention the heat stress in the HWO graphics. Given how much evapotranspiration is taking place, heat stress could ramp up quickly with hotter temperatures later next week, so persons in the ArkLaMiss will want to monitor the outlooks closely as there are indications that the subtropical ridge will become quite strong eventually over the south central CONUS. Otherwise, disorganized mainly afternoon and evening showers and storms can be expected with a few strong to severe microbursts possible each day. /EC/ && .AVIATION... 00Z TAF discussion: A band of showers and thunderstorms continues to push east across eastern Mississippi to start the TAF period, with lingering -RA to the west. Rain will gradually taper off near the TAF sites by around 03Z, with some chance for low stratus and patchy BR or FG to develop closer to 12Z near a few sites. Any MVFR or lower conditions should mix out through the day Sunday, with increasing chances for scattered showers and storms near most sites by around 18Z through 00Z Monday. /NF/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 72 87 73 91 / 46 55 17 41 Meridian 72 89 73 92 / 44 55 19 52 Vicksburg 72 89 73 91 / 50 54 12 23 Hattiesburg 73 91 74 92 / 49 51 13 53 Natchez 72 91 73 92 / 42 39 7 21 Greenville 72 87 74 91 / 51 66 16 26 Greenwood 72 89 74 92 / 38 60 17 35 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ NF/JNE/EC
Area Forecast Discussion
National Weather Service Melbourne FL
939 PM EDT Sat Jul 2 2022 .UPDATE... Current weather conditions are much quieter across east-central Florida with radar imagery showing that most of the rain has diminished. Although, a few isolated lingering showers remain mainly over the Volusia county offshore waters. With today`s activity primarily being driven by daytime heating and sea breeze interactions, quiet weather is forecast through the overnight hours. However, isolated to scattered showers and lighting storms will be possible overnight over the local Atlantic waters with the highest coverage expected along and to the north of the Brevard county waters. Low temperatures are forecast to drop into the low- to-mid 70s with partly to mostly cloudy skies. Diurnally driven showers and lightning storms will return to the forecast by the mid-morning hours nearshore with the threat shifting onshore into the afternoon as sea breeze collisions occur with outflow from upstream storms. && .AVIATION... VFR conditions prevail tonight and Sunday morning. S-SE winds becoming light (and variable inland) tonight, then resume around 8- 10 kts in the morning. Coastal terminals increasing to 12 kts in the afternoon with sea breeze development. High afternoon rain chances, especially along and north of the I-4 corridor, once again Sunday as anomalously high atmospheric moisture remains over FL. && .PREV DISCUSSION... /issued 244 PM EDT Sat Jul 2 2022/ Current... Scattered to numerous showers and storms ongoing, mainly along and west of the I-4 corridor. These showers and storms are generally moving east to southeast around 15-20 mph. The east coast sea breeze has formed and is pushing inland, with boundary collisions between outflow boundaries as well as the sea breeze occurring. Deeper moisture continues to filter in across the north, from around Melbourne to Kissimmee northward, with the 15Z XMR sounding showing a PW value of 2.14" with fairly warm temperatures aloft (-7 at 500mb). Highest rain chances this afternoon continue to be 60-70 percent across much of east central FL, except from Melbourne to Okeechobee southward where PoP is 40-50 percent. However, due to earlier start to convection today, coupled with higher cloud cover, convection may end a little sooner than anticipated, especially from Orlando westward, with the latest HRRR model leaning towards that trend. Main storm impacts today will be heavy rainfall of 1-3 inches in a 60-90 min period due to the slow storm motion, as well as frequent lightning, and wind gusts of 40-45 mph due to water loaded downdrafts. Temperatures will be warm and humid this afternoon with highs in the upper 80s to low 90s. Tonight... The Atlantic ridge axis will continue to build over the Florida peninsula through the time period. Lingering showers and storms expected through sunset, mainly from Melbourne to Orlando northward, with the latest HRRR model showing showers across Osceola as well. However, activity should decrease in coverage and intensity, and is expected to diminish by midnight. Light south to southeast winds overnight. Lows will be similar to last night, with lows in the low to mid 70s under cloudy to partly cloudy skies. Sunday-Tuesday...(Modified Previous Discussion) High pressure over the western Atlantic will maintain a ridge axis near to just north of east central Florida through at least early next week. This will allow deep moisture, with PWATs of 2"+, to persist over the local area. Thus, high coverage of showers and storms is expected to continue. Highest PoPs will remain across the interior, as onshore flow enhances the sea breeze, pushing initial convection along the coast in the late mornings/early afternoons inland as the day progresses. PoPs 60-70 percent for much of ECFL on Sunday, except 40-50 percent across the Treasure Coast. Otherwise, PoPs 60-70% west of I-95 each day. Coastal areas will see relatively lower chances at around 40-50%. Plenty of available moisture and light steering flow will maintain a locally heavy rainfall threat through the period, with up to 2-3" possible in a short period of time, which could lead to minor flooding. Temperatures remaining summer-like and near normal, in the lower 90s during the afternoons, with upper 80s possible along the coast. Morning lows in the mid-70s, though upper 70s will continue along the coast due to onshore flow. Wednesday-Late Week...(Previous Discussion) Deeper moisture is expected to remain in place on Wednesday, before slightly drier air begins to filter into the local area late next week. Higher PoPs persisting into Wednesday, before decreasing slightly to more "normal" ranges Thursday into the weekend. Chances around 50-60% area-wide on Wednesday, though the highest coverage is expected to remain across the interior. Then, PoPs 30-50% through the remainder of the period. SE/E flow will continue, as the ridge over the western Atlantic remains the dominant feature. As shower and storm chances decrease, afternoon high temperatures will tick upward, settling on possibly up to the mid-90s across the interior and lower 90s at the coast each day. Morning lows remaining in the mid to upper 70s. && .MARINE... Current-Tonight... Favorable boating conditions expected through the time period. SE winds 10-15 KT this afternoon as the east coast sea breeze pushes inland before winds shift to the S/SW across the northern waters and SE winds across the southern waters overnight due to the Atlantic ridge axis draped across the local waters. Scattered showers and storms this afternoon as convection pushes back towards the coast from the interior. As the sea breeze circulation diminishes this evening, low level flow will return to the larger scale synoptic forcing, veering S/SW across the north/central waters overnight. Seas 2-3 FT. Sunday-Wednesday...(Previous Discussion) High pressure over the western Atlantic will maintain SE/E flow through the period, though becoming S after sunset. Winds around 10-15kts. Scattered to numerous showers and storms are expected each day, with at least isolated activity persisting overnight. Seas 2-3ft. && .PRELIMINARY POINT TEMPS/POPS... DAB 74 91 74 91 / 20 70 30 50 MCO 74 92 75 93 / 20 70 20 70 MLB 75 89 77 89 / 20 60 20 40 VRB 75 90 75 90 / 20 60 10 40 LEE 75 91 75 91 / 20 70 30 70 SFB 74 91 75 91 / 20 70 30 60 ORL 75 93 77 94 / 20 70 20 70 FPR 74 89 75 89 / 20 50 10 40 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Fehling/Haley/Cristaldi
Area Forecast Discussion
National Weather Service Spokane WA
351 PM PDT Sat Jul 2 2022 .SYNOPSIS... There will be periods of showers and thunderstorms through the Fourth of July. Look for potentially heavy rain showers and lightning over the holiday weekend. The rest of next week looks to trend drier and warmer with showers and thunderstorms isolated and mostly over the mountains. && .DISCUSSION... Tonight through Independence Day: Closed low off the WA coast will slowly move east towards the region over the next 48 hours. Southerly flow ahead of the low will draw up increased moisture, lift, and instability into the region. Precipitable water will increase to near 150% of normal supporting locally heavy rain from thunderstorms. A Flash Flood Watch remains in effect for many of our northern counties (Bonner, Boundary, Chelan, Ferry, Okanogan, Pend Oreille, and Stevens). This afternoon eyes have been to our south over Central and Eastern Oregon as well as South Central Washington where a mix of surface based and elevated thunderstorms have been occurring. The strongest storms have been over NE Oregon which are tapping into the stronger surface based instability with RAP analysis showing 1500-2000 J/KG of surface based CAPE. The CAM`s models show this activity tracking northeast into the Camas Prairie and LC Valley region, and possibly SE Shoshone county this evening with the potential for hail, gusty winds, and brief downpours. A few storms could be strong or severe and will be monitored closely into this evening. Elsewhere tonight convection is expected to be mainly as the elevated variety and not as strong. However, an organized area of thunderstorms over Central Oregon may help generate a line of outflow winds across the Columbia Basin into the Spokane area and Palouse during the late evening and overnight hours. High res models show potential gusts of 25-35 MPH, locally to 40 MPH with this area of showers and thunderstorms. On Sunday a mid level wave tracking over the northern mountains/valleys and near the Cascades will provide a focus for steady moderate rains in the morning. With SE flow into the Cascades some model solutions show locally higher qpf of 0.50-1.00" in 6 hours in western Chelan/Okanogan Counties. This may lead to a sharp rise on the Stehekin River which is forecast to rise to just below flood stage by Monday. Will also have to monitor the burn scars with these higher rates. After this wave lifts north afternoon heating will destabilize the atmosphere for more showers and thunderstorms over the region. CAM`s models show the highest coverage over the northern valleys/mountains, with additional convection favored to develop over SE Washington into the ID Panhandle. With surface based CAPE as high as 1000-1500 J/KG and 0-6km shear values of 40 kts a few stronger storms are possible. On Independance Day yet another wave rotating the low near the WA coast will bring another round of showers and thunderstorms. Locally heavy rain are the main concerns with these storms. JW Monday night through Saturday: As the previous storm system shifts out of the Inland Northwest, precipitation chances will dwindle late Monday evening and overnight. Moisture isn`t completely swept out of the region heading into the middle of next week, so some weak impulses could kick off additional showers, most likely during the afternoon hours over the Cascades and northern mountains near the Canadian border. In general, however, we anticipate drier conditions with daytime temps warming back to near or slightly above normal into the latter stages of the week. /KD && .AVIATION... 00Z TAFS: This evening thunderstorms are expected to move out of NE Oregon into the Lewiston area with gusty winds expected with the storms. Additional shower and thunderstorm activity is expected into the overnight hours as elevated instability increases over the region. This may produce another round of gusty winds across the Columbia Basin into the Spokane area and Palouse. The boundary layer does moisten with the storms but given different degree of coverage/intensity between models confidence in CIGS lowering to below VFR isn`t great. A blend of the short term models including HREF suggests Pullman, and Spokane area TAF sites could lower to MVFR 15-18z Sunday. Shower and thunderstorm activity will continue thorugh the holiday weekend with heavy rain possible with stronger storms. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 60 73 55 71 52 77 / 30 60 50 50 20 10 Coeur d`Alene 59 73 56 70 52 77 / 20 80 60 60 20 10 Pullman 56 71 53 69 51 75 / 50 60 40 50 10 10 Lewiston 63 80 60 76 56 83 / 30 50 50 50 20 10 Colville 58 73 54 72 49 77 / 20 90 80 70 40 20 Sandpoint 58 71 54 69 50 75 / 20 90 70 70 30 10 Kellogg 58 71 56 67 52 74 / 40 80 60 70 20 10 Moses Lake 61 77 55 76 54 81 / 40 70 30 20 10 10 Wenatchee 63 74 55 75 54 80 / 60 80 30 30 10 10 Omak 61 76 57 75 52 80 / 20 90 70 70 40 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Flood Watch from 11 PM PDT this evening through Monday evening for Northern Panhandle. WA...Flood Watch from 11 PM PDT this evening through Monday evening for Central Chelan County-Northeast Mountains-Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-Wenatchee Area-Western Chelan County-Western Okanogan County. && $$
Area Forecast Discussion
National Weather Service Phoenix AZ
354 PM MST Sat Jul 2 2022 .UPDATE...0Z AVIATION DISCUSSION... && .SYNOPSIS... Conditions will generally remain unfavorable for Monsoon convection across the lower deserts the next several days, while better rain chances are expected across eastern Arizona. Near normal temperatures are likely early next week, followed by a warming trend. A return to above normal temperatures is anticipated by Thursday as high pressure builds across the Desert Southwest. && .DISCUSSION... Latest water vapor imagery reveals a weak vort max stretching from near Puerto Penasco into Pima County. RAP streamline analysis indicates this vort is part of an elongated trough that extends as far southward as the southern tip of the Baja Peninsula. This is helping to maintain a moist southerly flow across eastern Arizona. Further west, conditions are considerably drier as westerly flow predominates associated with a low pressure system across the Pacific Northwest and an anticyclone in the subtropical eastern Pacific. Meanwhile, surface dewpoints are in the upper 40s to lower 50s across central Arizona, which is resulting in a general lack of CAPE. HREF indicates little chance for Monsoon convection today across the lower deserts and only isolated activity is anticipated across southern Gila County. CAMs also indicate very low probabilities (less than 5 percent) of an outflow boundary reaching the lower deserts and consequently the threat of blowing dust is low as well. Unfavorable conditions for Monsoon activity will continue into Sunday as the dry southwesterly flow ahead of the Pacific trough builds eastward. Ensemble suites generally point to near average PWATs across central Arizona through the week, flanked by drier air to the west and deeper moisture across New Mexico. However, a closer look reveals considerable uncertainty in the individual members, mainly due to the presence and evolution of the aforementioned trough across Sonora. NBM forecast PoPs are generally quite low, even across the higher terrain north and east of Phoenix. However, a slight jog to the west as the trough lifts northward would result in higher precipitation chances Tuesday or Wednesday. There is less uncertainty in forecast temperatures as the ensembles suggest the anomalous ridge across the deep South and southern Plains will expand westward. This will translate into increasing thicknesses and a warming trend. Probabilities of reaching 110 degrees will increase from around 20 percent Thursday to 60 percent by next weekend. && .AVIATION...Updated at 2300Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Calmer conditions are forecast this evening as the atmosphere is generally more stable and activity to our SE appears less robust - leading to only around a 10% chance for an outflow to affect the terminals through the early overnight. Therefore, west breezes will shift back to the ESE between 7-10Z. Tomorrow, SW breezes should arrive by early/mid afternoon. Light southerly cross-winds possible at PHX around midday. Mid- level cloud cover should increase on Sunday - and could become BKN at times. Southeast California/Southwest Arizona including KIPL and KBLH: IPL- West breezes throughout with clear skies. Sundowner gusts up to 30kt possible this evening, potential is there again tomorrow evening. BLH- Generally S to SW winds throughout with clear skies. Afternoon/early evening gusts from 20-30KT. && .FIRE WEATHER... Shower and thunderstorm potential will be shifting into far eastern Arizona through the weekend with with a slight rebound into Gila County by Monday/Tuesday. With temperatures hovering not far from the seasonal normal, humidity values will generally trend lower with afternoon values falling closer to 10-25% as storm activity decreases. Overnight recovery should mostly range from 25-45% except somewhat higher over mountainous areas. Southwesterly winds will also increase in strength through the weekend particularly across southeast California and southwest Arizona though all areas will remain below critical thresholds. Downsloping winds across western Imperial county, including the Imperial Valley, during the next few evenings may create a few hours of elevated fire weather conditions. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Hirsch AVIATION...Heil FIRE WEATHER...Benedict/Iniguez
Area Forecast Discussion
National Weather Service Pueblo CO
323 PM MDT Sat Jul 2 2022 .SHORT TERM...(This evening through Sunday) Issued at 312 PM MDT Sat Jul 2 2022 Key messages: 1. Scattered thunderstorms expected into the evening, with locally heavy rain, small hail, gusty outflow winds and lightning all possible. 2. Afternoon thunderstorms again forecast for Sunday, greatest chances over the mountains/valleys/I-25 corridor. Scattered convection firing over the mountains/valleys this afternoon, with some activity building eastward along the Raton Mesa as well. Also seeing some storms developing in El Paso County, as old boundary drifts southward and encounters pool of deeper instability (CAPE around 1500 J/KG) centered over the Arkansas Valley from Canon City eastward through Pueblo to near La Junta. Lack of low/mid level shear (0-6km values 25 kts or less) limiting storm strength so far, with strongest activity near the boundary in El Paso County, and in the deeper moisture/more unstable air mass down along the NM border. For the evening, scattered storms possible many areas until sunset, best chance for a strong storm/heavy rain looks to be in Las Animas/Baca Counties where instability is greatest, though will have to keep an eye on Pueblo County also, as converging outflows and pool of unstable air interact from 22z-01z. Overnight, storms end over the eastern two thirds of the area, while at least some showers/isolated t-storms persist over the swrn mountains, as renewed push of deeper moisture arrives from NM. On Sunday, upper pattern changes little, though there may be a small upturn in convection as mid level moisture increases across the area. Shear/upper forcing will remain weak, so again most activity will be instability/terrain/boundary driven, with mainly a localized heavy rain threat over the higher terrain. Max temps will change little versus Saturday`s numbers over the mountains, with perhaps just a couple degf upward drift in readings on the plains. .LONG TERM...(Sunday night through Saturday) Issued at 312 PM MDT Sat Jul 2 2022 Key messages: 1) On Sunday evening, isolated to scattered PM thunderstorms could still be lingering around for several locations along the I-25 corridor and central plains. A few storms will also be possible over the mountains and San Luis Valley, even after midnight. 2) Scattered PM thunderstorms over the mountains and isolated storms over the plains will be possible on Monday, mainly I-25 corridor. Better chance of PM storms over plains on Tuesday through Thursday. Flash flooding could be possible over the mountains, especially over burn scar areas. 3) PM storms will be more confined to the mountains next Friday and Saturday. A slight chance of flash flooding will continue to be possible over the mountains, especially over burn scar areas, 4) Temperatures will return to right around the seasonal average, then become much warmer by Friday and through next weekend. Detailed discussion: Sunday night through Monday... Scattered to numerous thunderstorms which have formed over the mountains during the afternoon will be moving out over the plains during the evening on Sunday and into early Monday morning. The latest CAMs generally agree with most of the thunderstorms moving over northern areas of the I-25 corridor and over the central plains and possibly a few isolated storms over the far eastern plains closer towards midnight. The also HRRR keeps some new thunderstorm development over the San Juan and Sangre de Cristo Mountains until early in the morning hours on Monday with the continuous southwesterly mid-level flow overhead. The NAM does show instability dropping off quickly after midnight over the mountains, so it is more likely that only showers will remain after this time and not much in the way of any thunderstorm activity. The best CAPE and shear over the area during the evening will be over the mountains and mainly west of the I-25 corridor, with the highest values of CAPE of nearly 2000 J/kg over the southern Sangre de Cristo Mountains and highest areas of bulk shear will be over El Paso County and transitioning to Pueblo County of near 35 kts, and also the central and northern Continental Divide of shear near 40 kts. Given these values, an isolated stronger or severe thunderstorm cannot be ruled out before 9 PM. There will also be steeper mid level lapse rates along the central and northern portions of the I-25 corridor. The NAM3km does show inhibition over the plains setting in after 6 PM, which may help to weaken any thunderstorms that do move over these areas. Although DCAPE values are low, soundings do reflect relatively high LCLs, therefore the cores will be quite elevated and any collapsing cells may result in stronger outflow winds as the main threat. Also with the elevated cores, hail may be an issue, especially over areas of the northern I-25 corridor and Palmer Divide where CAPE values are higher. The other issue with the highest areas of CAPE over the southern Sangre de Cristos will be if any thunderstorms develop over the mountains and fail to move off due to weak mid-level shear. If this occurs, it may produce torrential rainfall and potential flash flooding before 8 PM, with burn scar areas being the most vulnerable. On Monday, the monsoonal moisture plume is going to begin to shift a little more to the west and north as the ridge over the region further strengthens. This will allow for afternoon and evening thunderstorm activity to be more confined to the mountainous areas of the CWA. There could be some thunderstorms moving off the mountains and over the adjacent plains by later in the afternoon, although given the mid-level flow being more from the SSW and fairly weak, this should not allow for thunderstorms to move much further east than the I-25 corridor. Most of the convection with the highest precipitable water looks to remain over the the central and southern areas of Continental Divide, as well as the southern Sangre de Cristo Mountains. Given these favorable values most unstable CAPE of around 1400 J/kg and steep mid level lapse rates between 7.5 C/km and 8.5C/km, along with relatively weak shear, stronger storms with high rainfall rates may occur and keep the risk of torrential rainfall over these mountains with the burn scars areas most prone to flash flooding. Instability does appear to be better over the eastern plains than it has been in model runs over the previous days with the NAM, however, the SREF still shows the better CAPE being over the western half of the CWA. Tuesday through Thursday... Ensembles and deterministic models alike continue to show consistency with long wave troughing over the northwestern CONUS remaining nearly stationary and keeping the ridge over central CONUS throughout this period in the forecast. 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. There will be a weak cool front moving through late afternoon on Tuesday, with winds shifting to a northeasterly-easterly direction over the plains, which will allow for a slight cooldown on 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 and result in potential flash flooding, especially over burn scar areas, for all 3 days during the afternoon and evening hours. Friday through Saturday... By Friday, as the ridge begins to build back again over the region and the upper level high over Texas begins to slightly retrograde 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 over western Colorado showing up on the ECMWF at the 500mb level on Friday. The GFS heights are not quite as high so perhaps not being quite as hot if this model resolves the strength of the ridge better than the ECMWF. -Stewey && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 312 PM MDT Sat Jul 2 2022 VFR at all taf sites the next 24 hrs, with vcsh at the terminals until 01z-03z this evening. Still low risk of a vcts as well, though will monitor radar trends before adding a mention into the tafs, as most storms have been small and fairly short-lived so far this afternoon. Slow clearing of mid level convective debris then expected after 03z. Little change for Sunday, with vcsh after 20z- 22z, and a risk of vcts 22z-00z. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...STEWARD AVIATION...PETERSEN
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
513 PM MDT Sat Jul 2 2022 .DISCUSSION...(This Evening Through Saturday) Issued at 229 PM MDT Sat Jul 2 2022 WV imagery at this hour shows general subsidence across nern WY and wrn SD, with the exception of initiating convection over the nrn Black Hills and modest cu fields elsewhere, the most pronounced of which extends from portions of the Badlands swd toward the Sandhills. CI over the nrn hills is occurring in the vicinity of an upslope convergence boundary, along which CI has failed over the past hour or so, particularly farther south. 20z SPC mesoA shows a moderate-CAPE near-storm environment (MLCAPE around 1000 J/kg with locally higher amounts up to 1500 J/kg). Deep-layer shear vector magnitudes are in the 35-40 kt range, and local backing near the hills supports an additional 5 kt or so. As such, the environment is likely suitable for rotating updrafts over the Black Hills. As convection moves away from its initiation point, however, it will be facing the aforementioned broad subsidence and relatively drier air. Therefore, outside of very strong updrafts, storms may struggle to move off of the terrain for now. Each failed updraft would presumably precondition the downstream environment for the next, though, so a successful updraft may become more likely with time. Upstream, a more pronounced region of ascent is evident across cntrl/wrn WY, leading to fairly widespread ongoing and developing convection there. This convection will likely grow upscale as it moves thru cntrl WY this aftn, potentially impacting wrn portions of our area by the evening. DCAPE of 1000-1500 J/kg and 0-3 km shear vector magnitudes of 20-25 kt could support strong downdrafts and maintenance of an MCS from cntrl WY into nern WY and--potentially-- toward the Black Hills later this evening. A final area of CI to note is across ern MT near the nose of a low-level theta-E ridge. Arguably the strongest forcing via low-level convergence across the region is there, and deep-layer shear is about 10 kt stronger. Thus, the environment across ern MT is supportive of supercells, which--if they remain discrete and travel along the right-moving Bunkers vectors--will have largely uninhibited access into, and fairly long residence times in, the unstable sector. Consensus of 12z CAMs and recent HRRR runs suggest this corridor is most favorable for long- lived supercells capable of large hail. If this scenario plays out, far nwrn SD could be impacted in the 00-03z time frame. Confidence is relatively low in the severe threat elsewhere; however, severe hail/wind could occur with any storms that manage to emerge off of the Black Hills, while any MCS moving into nern WY later this aftn/eve could pose primarily a wind threat. Tomorrow again looks favorable for strong to severe storms. Differences tomorrow compared to today are 1) higher low-level theta- E and steeper midlevel lapse rates, corresponding to overall higher CAPE/buoyancy; 2) slightly weaker deep-layer shear, though mesoscale perturbations owing to overnight/early AM convection could affect this; and 3) higher PWATs, increasing to 125 to 150% of normal. Best low-level moisture content will be over s cntrl SD, with generally deeper, drier boundary layers anticipated with wwd extent (outside of the Black Hills). NAM/HRRR fcst hodographs in this area show reasonably large clockwise curvature, with around 100-200 m2/s2 of 0- 3 km SRH. However, 0-1 km SRH is paltry. Given increased low-level moisture/lower LCLs, not out of the realm of possibility that we could see a tornado in this area, but it would likely require some localized help to support higher low-level shear/SRH. Other concern that may crop up tomorrow is locally heavy rainfall given above normal PWATs and--potentially--slower storm motions as a midlevel jet streak to our east attempts to further propagate away from the area. Given improved thermodynamic environment and subtle height falls (compared to height rises today), suspect that storm coverage will be a bit greater than today, as well. General zonal flow with low amplitude, shortwave perturbations owing to a wrn CONUS trof will likely reside over the region thru the middle of next week. This will bring continued unsettled conditions, with daily chances for storms--some of which could be severe and/or produce locally heavy rainfall. Stronger ridging may build over the Four Corners/Rockies regions late next week into the weekend; if so, this pattern shift could bring hotter and drier conditions to nern WY/wrn SD. && .AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening) Issued At 510 PM MDT Sat Jul 2 2022 Showers and thunderstorms are moving into NE WY and expected to impact the KGCC terminal within the next hour or so. These storms will continue eastward throughout the evening, potentially impacting KRAP by around 03z. Opted to keep TS out of KRAP TAF for now due to some uncertainty on timing though will keep monitoring the ongoing convection in WY. Thunderstorm activity should be out of the area by 07z. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION...Sherburn AVIATION...Wong