Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/03/20

Area Forecast Discussion
National Weather Service Bismarck ND
938 PM CDT Thu Jul 2 2020 .UPDATE... Issued at 930 PM CDT Thu Jul 2 2020 Updated to remove severe watch WW324. An isolated strong to very low end severe storm will be possible for the next hour or two along the line of convection, but the overall trend is lowering intensity. Bismarck just had a wind gust to 49 knots in the wake of convection. UPDATE Issued at 910 PM CDT Thu Jul 2 2020 Passing on that if current trends continue in storm intensity decreasing we will be dropping the rest of severe watch WW324 for the rest of North Dakota. To do this, if warranted, before the 10 PM newscast would be an excellent service. UPDATE Issued at 839 PM CDT Thu Jul 2 2020 Update to remove the western half of severe watch WW324. Storms are being kicked east by the impending H5 wave and entering a less favorable environment for severe. Hail risk, with the line of storms, has become less of a concern now than gusty winds. UPDATE Issued at 755 PM CDT Thu Jul 2 2020 Strong to severe thunderstorms continue to propagate northeast through central North Dakota as of this writing. Convection initiated in an area of moisture pooling along a surface boundary through western North Dakota. That boundary was pushing slowly east. An H5 wave pushing in from the west has been the kick to gets storms moving as initially they were very slow moving. Question becomes how much longer can convection sustain itself before it outruns the favorable shear and increasing inhibition as evening sets in. Along the U.S. Highway 83 corridor MLCape is running 2000-2500J/KG while the latest RAP analysis shows CIN increasing. Just a few hours ago the effective shear had shown a marked increase into the central part of the state, and now that was shifting back to the west again. With that said, will expect the overall intensity of convection to weaken over the next few hours, but not completely dissipate, with isolated severe storms still possible at least until 10 PM CDT over the watch area. Have removed Slope, Bowman and Adams counties from the watch as storms have moved out of there and the risk of severe weather there has significantly decreased. UPDATE Issued at 535 PM CDT Thu Jul 2 2020 Forecast updated for new WW324 severe thunderstorm for most of central and into southwest North Dakota. Storms have broken loose on the west edge of the CAP near the surface boundary and were clustering toward the northeast. Will expect storms to continue to fire toward the east with the western North Dakota surface boundary as it inches east. && .SHORT TERM...(This evening through Friday) Issued at 327 PM CDT Thu Jul 2 2020 The main concern for the short term period is chances for severe thunderstorms. Closed upper low continues to spin over central Alberta with a positively tilted ridge axis from the Great Lakes to Texas. A pre- frontal surface trough is analyzed from near Mohall to Buffalo, SD, and is a bit farther west than previously expected. Convection initiation appears to be underway along/just ahead of the surface trough in southwest North Dakota where SBCIN is eroding. SPC mesoanalysis places up to 5000 J/kg SBCAPE and around 40 kts effective bulk shear over the area. Initial storms should remain discrete. Upscale growth into clusters/linear segments is possible, but not a certainty due to weaker mid/upper level forcing, and right- moving Bunkers vectors would likely move discrete supercells away from the surface boundary. The main hazard is expected to be very large hail, with damaging winds also possible. The tornado threat is marginal at best, mainly due to relatively high LCLs, but still greater than zero. It is unclear how far north and east the threat for severe weather may expand, mainly due to capping concerns. Further to the east, sub-severe convection has been percolating over central North Dakota along a corridor of strong low level southerly flow. Much greater CIN and weaker shear will likely keep this activity below severe limits. There is potential for the development of additional convection overnight from southwest into central North Dakota on the nose of a low level jet and associated low to mid level moisture transport. Forcing may be aided by mid level shortwave energy. This potential is likely highly contingent on the latitudinal placement of the LLJ/moisture transport, which may be influenced by remnant outflow boundaries from convection this afternoon and evening. MLCIN will obviously be present at this time of day. But interestingly, the RAP does show a weakening trend in the cap after midnight CDT. If air parcels are able to break through the EML, MUCAPE and effective bulk shear would promote a severe threat, which may continue into Friday morning. Details on timing and location of convection Friday and Friday night remain murky at best. There is general agreement for active southwest flow aloft topping a Central Plains ridge, with strong moisture advection in low level southerly flow. The trend in CAMs has been for mostly dry weather during the afternoon, while some global models suggest meandering MCSs through the day. The potential for early morning convection further complicates the picture and decreases predictability. However, the environment over this time period will generally contain steep lapse rates, CAPE greater than 2000 J/kg, effective shear greater than 30 kts, and precipitable water greater than one inch. Any storm/complex of storms will be capable of producing large hail, damaging wind, and torrential rainfall. Of particular concern is the potential for training convection as Corfidi vectors are oriented perpendicular to moisture transport vectors, with mean 700-300 mb winds less than 30 kts. .LONG TERM...(Friday night through Thursday) Issued at 327 PM CDT Thu Jul 2 2020 Above normal temperatures and chances for thunderstorms, some severe with heavy rain, highlight the long term period. Long range guidance continues to favor a stagnant weather pattern through the middle of next week, with persistent Pacific Northwest troughing and broad ridging from the Southern Plains to the Upper Mississippi River Valley. This leaves the local area in an active southwest to quasi-zonal flow pattern, with mostly above normal temperatures, humid conditions, and daily chances for thunderstorms. The hottest day is expected to be Independence Day, with afternoon heat indices in the mid to upper 90s from south central North Dakota into the James River Valley. Forecast instability and shear parameters along with climatology suggest any round of thunderstorms has the potential to include severe weather. This thinking is supported by CIPS analogs, which bring relatively higher probabilities (at least 15 percent) of severe weather into at least part of North Dakota every single day. Of greater concern may be the potential for heavy rain. Periods of strong low level moisture transport are forecast to intercept east- northeastward propagating MCSs in an environment with above normal precipitable water and deep warm-cloud layers. This potential threat looks to be maximized Saturday afternoon through Sunday night. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 930 PM CDT Thu Jul 2 2020 Scattered thunderstorms are forecast through the forecast period, mainly across southwest and central ND. Beyond this evening, predictability of timing and location of storms is low. Expect periods of IFR to LIFR visibility, sporadic gusty winds, and hail within thunderstorms. Outside of storms, VFR conditions will prevail. Wind direction and speeds will be highly variable depending on where the surface boundary through western North Dakota meanders to. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JPM/TWH SHORT TERM...Hollan LONG TERM...Hollan AVIATION...JPM
Area Forecast Discussion
National Weather Service Duluth MN
929 PM CDT Thu Jul 2 2020 .SHORT TERM...(This evening through Friday night) Issued at 351 PM CDT Thu Jul 2 2020 A high amplitude upper-level ridge in place across the region will remain in place through the short term. High pressure at the surface and stagnant flow will result in warm temperatures and light winds. Scattered showers and thunderstorms have developed along a lake breeze in northwest Wisconsin this afternoon. MLCAPE along the lake breeze is 2200-2800 J/kg based on the latest RAP run and deep layer shear is very weak, around 5 knots. Look for the weak convergence along the boundary to continue through early evening. The combination of weak convergence and very low shear means any storms which develop will be upright and relatively short-lived. Fog is likely once again tonight, especially for our Minnesota zones. Visibility of may be as low as one-quarter mile in spots. Fog will clear Friday morning with abundant sunshine expected during the morning hours. Self-destructive Cu will percolate by late morning and afternoon from north-central to central Minnesota and east across northwest Wisconsin. With weak forcing and light winds, a few vigorous cumulus may develop into showers during the afternoon and evening hours, but kept forecast dry for now due to low predictability in timing and aerial extent of the showers. Temperatures will be quite warm with highs in the upper 80s and low 90s. Areas near the Lake Superior shore may benefit from a weak lake breeze and will keep temps limited to the upper 70s and low 80s. Storms are forecast to develop in central North Dakota Friday afternoon and evening and may push into north- central Minnesota Friday night and Saturday morning. Have included a chance of showers and storms overnight to account for that potential. .LONG TERM...(Saturday through Thursday) Issued at 351 PM CDT Thu Jul 2 2020 The forecast for the Fourth of July looks to be very warm with highs in the upper 80s to low 90s along with a chance for showers and thunderstorms in the afternoon and evening. These showers and storms are in association with an approaching MCV from the Dakotas. MLCAPE of 1000-1500 J/kg and shear values up to 30 knots should help support thunderstorm development. At this time, SPC has NE MN under a marginal risk for severe storms. Given the uncertainty with this system, current confidence in severe weather is low. The main concern relates to the strength of any convection that initially develops to the west over the Dakotas. For Sunday through next week, a trend of diurnal thunderstorms sets in. The best chance for any widespread convection will be Monday, as a cold front propagates across the Northland. Upper level flow transitions from ridging to more zonal for the first half of the week. This should help to reduce temperatures a bit with highs in the mid to upper 80s throughout next week. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 622 PM CDT Thu Jul 2 2020 This afternoon a small line of storms kicked off by the surface convergence of the lake breeze over NW WI are showing signs of weakening. These storms will continue to decay and disappear within the next couple of hours. INL will stay VFR through the TAF period. Elsewhere, fog is expected to develop overnight once again and reduce visibilities. Current expectations are for the thickest fog to be over HYR where LIFR conditions are the most likely. Clear skies will quickly burn the fog away shortly after sunrise and VFR conditions will continue through Friday. && .MARINE... Issued at 928 PM CDT Thu Jul 2 2020 The marine forecast for the next 48 hours looks quiet. High dewpoints will give way to fog developing tonight and tomorrow night over the lake. Light winds and waves less than 2 ft will continue through the period with high pressure remaining in place over the Northland. Chances of rain return Saturday afternoon. && .PRELIMINARY POINT TEMPS/POPS... DLH 65 88 61 88 / 10 0 10 20 INL 63 93 64 88 / 0 10 30 40 BRD 66 90 65 88 / 0 10 10 30 HYR 63 92 61 92 / 20 10 10 10 ASX 64 89 60 91 / 10 0 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ SHORT TERM...Huyck LONG TERM...Huyck/Unruh AVIATION...Britt/LE MARINE...Britt/LE
National Weather Service Hastings NE
714 PM CDT Thu Jul 2 2020 .UPDATE... Issued at 710 PM CDT Thu Jul 2 2020 Have increased PoPs to likely for tonight over the S/W due to latest radar trends. Latest SPC Mesoanalysis places 4000-4500 J/kg of MLCAPE over SW/W portions of the CWA, with effective deep layer shear rather weak at 25-30kt. Convection over SW NE/NE CO has grown upscale into an organized/mature QLCS with a general motion to the ESE around 30kt. This would place arrival time to Furnas Co area around 0030-0100Z. This activity has generated a significant cold pool (air temps in low to mid 60s under/behind line of tstms) and several 50-70mph gusts have been reported...including 74mph just W of KMCK. Given the weak deep layer shear, linear mode, organized cold-pool...fairly high confidence that the greatest threat will be strong-dmg winds of 50-70mph. Question is how long this will last? While expect a gradual weakening trend, the current trends suggest a svr threat will probably exist for at least areas from Elwood to Stockton...with E extent of svr risk possibly as far E as EAR to HJH. 0-3km shear vectors as well as Corfidi vectors turning more SE-SSE suggests this activity should turn a bit as this activity spreads E toward 04Z-05Z. Diurnal decr in instability should help tstms gradually decr toward 06Z. Like the general idea of both the HRRR and HRRREXP, though both are 1-2hr too slow. Reference SPC MD #1086 for latest thoughts on potential new watch. && .SHORT TERM...(This evening through Saturday night) Issued at 500 PM CDT Thu Jul 2 2020 Covering the first first 5 periods/60 hours in this section, by far the main challenge are VERY tricky-to-forecast rain/thunderstorm chances (PoPs), while confidence is considerably higher in other elements such as high/low temperatures and winds. To be very honest, these type of "summery" weather patterns with subtle forcing aloft drive this forecaster nuts, because although we "know" that most areas will be dry most of the time, there is just enough potential for storms to mainly either roll in from the west off the High Plains and/or form "randomly" overnight along little low-mid level convergence zones (mainly rooted between 850-700 millibars), that we just have to keep various low PoPs in the forecast. Some of these low chances will certainly not come to fruition, but others likely will. As for severe thunderstorm potential: By far our main concern (and the one that carries any kind of modest-confidence at all) comes right away this evening-tonight, as the potential exists not only for spotty/more isolated activity almost anywhere, but also for possibly a more organized storm complex/mesoscale convective system (MCS) rolling in from the west. SPC currently has mainly western portions of our CWA assigned a Marginal to Slight Risk of severe, and if anything, kind of wish they would have more of our central counties in the Marginal as they had in the previous outlook, as a severe threat could easily extend to at least Highway 281 later if models such as the HRRR/NAMNest are onto anything. Briefly looking at the current/recent weather scene as of 430 PM: Overall, it`s been a dry day CWA-wide once the somewhat-unexpected early morning showers/storms in our far southeast zones faded away. Aloft, large-scale ridging dominates, but subtle embedded waves along with upslope low-level flow to our west has really ignited quite a bit of convection (some severe) to our west in the CO/KS/NE border area. At the surface, east-southeast breezes of generally 10-15 MPH with some higher gusts to around 20 MPH or slightly higher have prevailed today. High temps have topped out mainly upper 80s-low 90s. In the interest of time, will finish this section with some abbreviated comments on the next 5 night/day periods... This evening-overnight: See our latest Hazardous Weather Outlook (HWOGID) for our general expectations, but while the entire area will be prone to at least spotty convection at some point, our biggest concern will be with whether a more organized MCS will roll in from the west sometime after 7-8 PM. Worst-case scenario is a corridor of damaging winds of 70+ MPH, but with relatively weak ambient shear, this will depend more on how organized of an eastward-surging cold pool that storms to our west can form. Even late in the night, would not be surprised to see "random" showers/storms bubble up along mid-level boundaries (much as what happened in our southeast this morning). Low temps mid 60s west to around 70 east. Friday daytime: While confidence is high that most areas will be dry most of the day, lingering activity from the overnight hours (likely non- severe) could occur at least into the morning mainly within the eastern half of the CWA, and have this covered with low PoPs. For the afternoon, took a small chance and removed PoPs, calling for dry conditions as any storm development should remain well to our west. Otherwise, very similar to today temp-wise, with highs mainly a few degrees either side of 90. Breezes also similar, generally 10-15 MPH from the southeast with some higher gusts. Friday night: Although am not expecting nearly the potential for possible storms that tonight holds (especially those rolling in from the west), felt it was prudent to at least carry some basic slight chances given continued subtle forcing overnight. Likely dry for most areas though. Low temps upper 60s to around 70. Saturday daytime (Independence Day): Like today was and tomorrow should be, confidence is fairly high that the vast majority of the CWA remains dry, with simply another warm day with highs upper 80s-low 90s and slightly-breezy southeast winds. That being said, this is just far enough out in time that it falls into the time frame where our "default" multi- model blend is more "in control" of the forecast, and because it insists on some small rain chances being around, we continue to call for low-confidence slight chances most areas. Saturday evening-night: Much like the daytime period, most raw model data leans toward a dry evening-night for outdoor activities. However, especially our far western counties could see some potential for evening storms TRYING to drift in from the west. For now, will run with some slightly toned-down Pops from the default multi-model blend, with mainly 30 percent chances west and only 20s (slights) east. Low temps aimed mid-upper 60s. .LONG TERM...(Sunday daytime through Thursday) Issued at 500 PM CDT Thu Jul 2 2020 General overview of this 5-day period: Carrying the same theme of from the short term above, there is certainly more confidence regarding temperatures through this time frame than in "exact" rain/thunderstorm chances (PoPs). To put it bluntly, this is just a very "murky" weather pattern when it comes to having any great confidence in PoPs. In the mid-upper levels, we spend the vast majority of this time frame in a fairly weakly- forced, "typical" mid-summer weather pattern, as we reside south of the main upper jet axis that generally resides from the western through north-central CONUS. Thanks to the predominant ridging, mid level temps will be warm enough on most afternoons to likely prevent convection from firing in the absence of stronger forcing. That being said, we will certainly be prone to occasional storms/complexes wandering in from the west during especially the evening, along with very subtle low-mid level warm air advection- induced activity (mainly rooted 850-700 millibars) during the overnight and perhaps morning hours on some days. Precipitation/thunderstorm chances: Needless to say, this forecast is simply littered with low confidence thunderstorm chances, affecting at least portions of the CWA each and every day and night. While the vast majority of night and especially days will likely remain dry, these small (mainly 30 percent or less) PoPs clearly outline the uncertainty in the forecast. Obviously we will attempt to refine (increase/decrease) these POPs as periods move into the shorter- term range, but for now we just have to live with them all. As for severe storm chances, they are certainly not zero, especially given what will likely be appreciable instability much of the time, but given overall weak shear, it will difficult to forecast organized storm potential very far in advance. However, could certaintly foresee at least a few Marginal/Slight risk setups during this time. Temperature overview: Certainly, there is higher confidence here. Although the presence of pesky clouds and/or storm outflow could easily throw things off by 5+ degrees on a few days/nights, certainly the majority of these 5 days looks to feature highs between the upper 80s-mid 90s (some upper 90s more favored southwest), and overnight lows between the mid 60s and low 70s. In other words, a seasonably-hot, but not overly-hot weather pattern (not the type that would require formal Heat Advisories). && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday) Issued at 640 PM CDT Thu Jul 2 2020 Significant wx: Potential storms/outflow this eve, MVFR cigs near dawn Tonight: VFR to potentially MVFR. Generally low confidence period due to unknown track of storms off to the W. At the minimum, will get BKN to OVC cirrus, but depending on the track, both terminals may get side swiped by the convection, with generally better chcs just off to the S. Given uncertainties in track, kept VCTS for now, but did indicate a likely switch in wind dir 03Z-05Z to SW or W, due to outflow from this convection, as well as bring in some low cigs that could potentially be MVFR. Short term models exit/weaken the convection around 06Z. Can`t completely rule out additional elevated convection late overnight, but too low of potential to include attm. Finally, some models indicate BKN MVFR cigs near dawn for GRI, with maybe even lower cigs and patchy MVFR fog poss as well. Again, though, this is low confidence as will depend on convective trends. Fri: MVFR to VFR. Any low cigs should scatter and lift by mid- morning...leaving VFR conditions and occasional mid to high clds. Winds will be SE 6-10kt. Confidence: Medium. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...Thies SHORT TERM...Pfannkuch LONG TERM...Pfannkuch AVIATION...Thies
Area Forecast Discussion
National Weather Service Wichita KS
923 PM CDT Thu Jul 2 2020 .UPDATE... Issued at 923 PM CDT Thu Jul 2 2020 Diurnally driven convection, along a diffuse outflow boundary has led to convection propagating to the NW towards the convective complex currently moving east out of NW KS. The bigger concern, now, is the strong/severe complex of storms moving E into KHYS and what is the path of this complex of storms late this evening and overnight. Current RAP propagation vectors suggest that this complex will continue to move E-SE as it progresses into central KS, possibly taking more of a turn to the SE with time towards McPherson and Marion, as the complex follows the main instability axis to the SE. Could see damaging winds along the bowing segment with heavy rainfall as well, given the very unstable airmass. After coordination with SPC, gonna issue a SVR Watch for portions of central KS for the damaging wind threat. Ketcham && .SHORT TERM...(This evening through Sunday) Issued at 300 PM CDT Thu Jul 2 2020 Morning convection which moved across the southern Flint Hills has evolved into a decent MCS this afternoon across eastern Oklahoma. This has stabilized much of the area in the wake of the outflow boundary which arches from central Oklahoma into portions of southwest Kansas. This will focus the more robust convection west of the forecast area late this afternoon. As the weak mid-level flow becomes more northerly this evening, it may tend to keep much of this convection from developing/moving too far east into central Kansas. However, airmass recovery is expected within the reservoir of elevated low level moisture across central and eastern Kansas later this evening, so will expand slight/modest PoPs overnight. Weak northerly flow aloft looks to be maintained across the area through Independence Day with instability axis across eastern Kansas. While chances for organized convection look low, cannot rule out a few storms the next few days. Temperatures should average near or slightly above early July climo, though will likely stay just below the 105 heat advisory criteria. Darmofal .LONG TERM...(Sunday night through Thursday) Issued at 300 PM CDT Thu Jul 2 2020 Upper ridge will retrograde across the Southwest CONUS late in the weekend through early next week as weak troughing over the high Plains migrates across the area. This may provide modest precip/convective chances across the area. KED && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 700 PM CDT Thu Jul 2 2020 Diurnally driven convection continues across south central KS and extreme SE KS at this time. Most of the convection is flirting with the KHUT/KGBD and KCNU taf sites. Current propagation of the south central KS storms, are moving to the NW, towards the KGBD taf site. So will go with VCTS for the KGBD and KHUT taf sites. Will also include VCTS for the KCNU taf site, as outflows from the convection to east of CNU may propagate back to west. Think most of the convection is diurnally driven, with most of the convection expected to wane a couple of hours after sunset. VFR conditions are expected overnight into Fri. There is another chance of isolated storms across south central KS on Fri afternoon. For now, will not include a VCTS in for this chance, as pinning down the location of any storms is too far out to pinpoint just yet. Ketcham && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 72 95 71 94 / 30 20 20 20 Hutchinson 70 95 70 94 / 50 20 20 20 Newton 71 94 70 93 / 50 20 20 20 ElDorado 70 93 70 92 / 30 20 20 20 Winfield-KWLD 73 94 72 93 / 30 20 20 20 Russell 68 94 69 93 / 60 10 20 20 Great Bend 68 95 69 94 / 60 10 20 20 Salina 71 94 70 93 / 50 20 20 20 McPherson 70 94 69 93 / 50 20 20 20 Coffeyville 74 93 72 92 / 20 30 20 20 Chanute 73 92 72 91 / 20 30 20 20 Iola 72 91 71 90 / 20 30 20 20 Parsons-KPPF 73 92 72 91 / 20 30 20 20 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Ketcham SHORT TERM...KED LONG TERM...KED AVIATION...Ketcham
Area Forecast Discussion
National Weather Service Phoenix AZ
810 PM MST Thu Jul 2 2020 .SYNOPSIS... As high pressure builds into the region, a warming trend will allow highs to climb back above normal by this weekend, and continue well into next week. While there is a very slight chance of thunderstorms for parts of south-central Arizona this evening, much of the area likely will not experience storms directly. However, some wind and dust would be more common. A drying trend beginning this weekend will not favor storm development for the holiday weekend and early next week. && .DISCUSSION... Though not particularly evident in satellite imagery, objective analysis suggests a subtle midlevel perturbation propagating through south-central AZ this evening providing just enough support to spur a couple isolated storms in an otherwise convectively marginal environment. 00Z KPSR sounding data sampled only 9 g/kg mixing ratio extending through the sfc-H7 layer yielding MLCape just at 300 J/kg, but still a notable CinH nose just above the top of the boundary layer. KTWC sounding data had slightly better moisture profiles (10 g/kg) with only somewhat better thermodynamic measures. The aforementioned wave infusing or concentrating moisture into the CinH layer along with some weaker outflow boundaries did eventually get some storms going in an environment rich with DCape values in excess of 1000 J/kg. Individual storms have easily produced concentric outflows (generally isolated gusts 40 mph), though thus far these outflows have been fairly shallow and weakening rather quickly after spreading from the initial downdraft (although still traveling a good distance from their initiation and kicking up localized dust). The isolated nature hasn`t produced deeper or more consolidated outflow yet that would be necessary to displace the entire boundary layer and erode a larger expanse of the inhibition aloft. However, the recent storms in western Pinal County have displayed better linear outflow and impetus for new storm development. That said, a cooling boundary layer and output from high res models which have been moderately accurate this evening (i.e. HRRR and ARW core) don`t offer much hope of storms lasting much longer into the evening. Boosted POPs in this area of interest for the remainder of the evening, and made some adjustment of other parameters based on recent observational trends. && .PREVIOUS DISCUSSION... /445 PM MST Thu Jul 2 2020/ A warming trend gets underway on Friday as the ridge continues to work its way west closer to the region. Above normal highs will climb to near 108 to 110 by Saturday and remains near 110 through Tuesday. With significant moisture in place a weak disturbance over AZ along the NW flank of the ridge could trigger some isolated thunderstorms mainly across the N AZ high country on Friday into Saturday. The ridge will also likely keep additional storms confined mainly to SE and far E AZ for the late tomorrow afternoon and early evening. Also beginning Friday is a gradual zig-zag drying trend as the ridge axis retrogrades further to the W-SW and moisture and instability along the S flank of the ridge will keep the best storm chances confined mostly to SE AZ and NW MX for early next week with only very slight chances for a renegade storm in the lower deserts or closer to Phoenix. In addition, moisture continues to gradually decrease with ensemble mean regional PWs falling to generally less than 1" during the weekend. && .AVIATION...Updated at 2345Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Fairly low confidence aviation forecast through Friday afternoon with variable wind directions through early this evening, then the potential for a weakening outflow boundary later in the evening. Winds will likely keep a 160v230 heading into mid evening before the preponderance of models suggest finally switching to SW, and persisting into the overnight. The switch back to east may be delayed until sunrise, or possibly later. TS activity should remain well southeast of terminals and dissipate a few hours after sunset with only some high clouds streaming into central AZ. Conditions should return to a more quiet, stable pattern Friday afternoon. Southeast California/Southwest Arizona including KIPL and KBLH: Very little aviation concerns will exist through Friday afternoon under mostly clear skies. Winds at KBLH will favor a southerly direction though the typical period of variability of light north drift will be likely Friday morning. KIPL winds may briefly become gusty during the mid evening as directions switch to the west, however trends in directional shifts should be similar to the past couple days. && .FIRE WEATHER... Sunday through Thursday: No changes to the fire weather outlook...Significantly above normal highs near 110 continue through around Tuesday with highs staying above normal through the period. A gradual drying trend continues through midweek. However, there is still a very slight lingering chance of a few isolated storms focused over higher terrain areas of the eastern districts though rainfall may not be very widespread or heavy with any isolated storms. Afternoon minimum humidity values will generally fall between the single digits in the far west and the low to mid teens elsewhere, while overnight maximum RHs look to vary between 25-40%. Typical afternoon breezes with gusts up to 18-24 mph will be likely with some localized stronger outflow winds possible near any renegade storms. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...MO/Sawtelle AVIATION...MO FIRE WEATHER...Sawtelle/Smith
Area Forecast Discussion
National Weather Service Springfield MO
628 PM CDT Thu Jul 2 2020 ...00Z AVIATION UPDATE... .SHORT TERM...(This evening through Friday) Issued at 240 PM CDT Thu Jul 2 2020 Hot and humid conditions are in place across southwest Missouri and southeast Kansas this afternoon. Did go ahead and upgrade heat advisory to an excessive heat warning for McDonald and Newton counties, where slightly higher dew points have raised heat index values above 110. 12Z SGF sounding shows all the moisture confined below 850mb (Approx 5000 feet), with very dry air above this. RAP does indicate a little better moisture pushing into southwest Missouri and far southeast Kansas this afternoon and evening. Expect Isolated thunderstorms into the evening hours as surfaced based instabilities of 5500-6000 j/kg are present, with weak shear. Best chances for any stronger to potentially severe would be in this corridor of higher moisture over southwest Missouri into southeast Kansas. These will likely weaken with loss of heating, but given the humid airmass, much like last night will likely see isolated showers/storms through the overnight hours.Look for lows tonight mainly in the lower to middle 70s. Temperatures will be somewhat cooler on Friday, with highs ranging from the middle 80s in the eastern Ozarks to the lower 90s in southeast Kansas and far southwest Missouri. It will remain quite humid though, but heat index readings at this point look to remain below advisory levels, generally in the mid to upper 90s and perhaps 100 over southeast Kansas, so at this point no advisory headlines will be issued. With the heat and humidity will once again see the possibility of isolated to scattered storms during the heat of the day. No widespread severe weather is expected, but as it typical this time of year could see an isolated stronger storm. .LONG TERM...(Friday Night through Thursday) Issued at 240 PM CDT Thu Jul 2 2020 This period will be dominated by a persistent upper level ridge over the area. This will keep warm and humid conditions for the area with at or above normal temperatures. Daily, mainly diurnally driven convection will occur, but plenty periods of dry weather. Temperatures actually look to cool a bit for the upcoming weekend with highs in the upper 80s to around 90. Weak surface high pressure looks to build in from the north on Sunday, and this will likely be the "driest" day of the weekend. Otherwise, temperatures begin to climb back up into the 90s by the middle part of next week with heat indices once again topping 100 degrees in many locations. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 624 PM CDT Thu Jul 2 2020 Thunderstorms will start the TAF period at BBG however should remain dry at JLN and SGF. VFR conditions are expected at the sites through most of the period. Could be some brief MVFR around 12Z however confidence is not high enough at this time to include. winds will remain light and out of the northeast generally. There is a chance for additional showers and storms Friday afternoon however confidence is too low at this time. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...Heat Advisory until 8 PM CDT this evening for Moz066-077>079- 088>090-094>096-102>105. Excessive Heat Warning until 8 PM CDT this evening for MOZ093- 101. KS...Heat Advisory until 8 PM CDT this evening for KSZ073-097-101. && $$ SHORT TERM...Raberding LONG TERM...Raberding AVIATION...Burchfield
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
801 PM EDT Thu Jul 2 2020 .AVIATION... Prevailing VFR through the period with persistent westerly flow. Winds will subside tonight but begin to pick up to AOA 12 knots late morning into afternoon hours, perhaps becoming gusty at times. VCSH starting out early in TAFs, transitioning to VCTS by 17-18z. Lower rain chances across southern terminals so therefore have left out any rain mention for FMY/RSW. && .MARINE... West-southwest winds generally around 10-15 knots will prevail over the gulf coast waters as high pressure ridges over southern Florida. Daily scattered showers and an isolated thunderstorm will be possible each day with the highest chances north of Tarpon Springs earlier in the day. No headlines are expected and the only hazards expected through the end of the week and into the weekend will be associated with higher winds and seas as well as dangerous lightning associated with passing thunderstorms. && .Prev Discussion... /issued 630 PM EDT Thu Jul 2 2020/ UPDATE... Broad cyclonic flow aloft continues as the axis of a midlevel trough extends from SW-NE across the Atlantic seaboard. This flow, coupled with eastern Gulf SST in the mid to upper 80s (leading to MLCAPE around 1500 J/kg over the waters according to RAP analysis), has maintained sporadic showers and an occasional thunderstorm or two moving into the central nearshore waters. However, these are rather small in coverage and brief due to the quick eastward movement. A decrease in low-level lapse rates over the waters should be just enough shut this convection off shortly after sunset. Likewise, we will also see any stray shower or storm over land dissipate when we loose daytime heating... Convection will once again fire off over the northwest waters overnight, gradually working their way southward towards West Central Florida by early morning. Only have made adjustments to short-term PoPs to account for current trends and forecast thinking. && .Preliminary Point Temps/PoPs... TPA 92 80 91 79 / 20 10 50 40 FMY 93 79 93 79 / 10 0 20 10 GIF 93 76 93 76 / 30 10 70 20 SRQ 91 80 91 79 / 30 20 30 20 BKV 92 75 91 74 / 20 10 70 50 SPG 92 80 91 79 / 90 10 40 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION/MARINE...Norman UPPER AIR/DECISION SUPPORT...Rude