484 FXUS63 KGID 181100 AFDGID Area Forecast Discussion National Weather Service Hastings NE 600 AM CDT Wed Jun 18 2025 ...Aviation Update... .KEY MESSAGES... - While the majority of our forecast area (CWA) will be thunderstorm-free today, and severe storms are fairly unlikely, there is a non-zero chance that a stronger storm or two could produce small hail and/or gusty winds through late this afternoon. - Our attention increasingly-turns to this year`s first round of truly oppressive heat Friday-Sunday, with peak daytime heat index at least 100-105 most areas (especially Fri-Sat), and overnight lows providing limited relief dropping no lower than mid-upper 70s. At least a 2-3 day Heat Advisory is looking increasingly-likely in later forecast packages. - Along with the aforementioned heat, Friday-Sunday will also be a bit windy by late-June standards, with sustained speeds commonly 15-25 MPH/gusts 30-35+ MPH...possibly providing some relief but also giving it that "blast furnace" feel. - Our forecast remains dry this evening through Sunday daytime, before various, still rather uncertain rain/thunderstorm chances arrive Sunday night-Tuesday. && .DISCUSSION... Issued at 447 AM CDT Wed Jun 18 2025 -- 7-DAY FORECAST BIG PICTURE THOUGHTS, CHANGES, UNCERTAINTIES: - Overall no big changes versus previous forecast package, with the Fri-Sun heat clearly becoming the main focus. As touched on above, a 2-3 day Heat Advisory "headline" is probably on the table in the near future, especially considering it`s our first widespread 100-105 heat index situation of the year (and despite MOST areas probably falling a touch short of our long- standing "technical" Advisory criteria of 105+). Also worth noting is that experimental NWSHeatRisk maps 9which take into account the time of year, heat duration etc.) are pegging most/all of our CWA into the Major (level 3 of 4) category. - Backing up to today, and although not considered likely (we`re in agreement with SPC only assigning "general thunder" to our CWA), there does appear to be at least limited potential for an isolated, "sneaky" stronger storm or two capable of producing small hail/gusty winds, particularly this afternoon and mainly in counties north and east of the Tri Cities (just something to watch for/not get caught off-guard by). -- 7-DAY FORECAST CHRONOLOGICAL DETAILS: -- CURRENT/RECENT WEATHER SCENE AS OF 4 AM: Starting with some quick comments on yesterday afternoon- evening, it was very clear that one "silver lining" to the widespread thunderstorm/scattered severe activity Monday evening-night was that it cleaned out/"junked up" our environment for anything resembling a repeated severe threat for Tuesday (instead focusing the vast majority of regional severe weather to our south). That being said, some very spotty and even briefly- strong storms did flare up with afternoon heating in limited parts of our CWA. As for the ongoing overnight-early morning period, the vast majority of our CWA has thus far remained dry/storm-free, with the main notable exception being Valley/Greeley counties in our far north, where a small line/cluster of non-severe storms pushed in from the west over the last few hours, largely tied to a small-scale disturbance (MCV) embedded within a broader/larger scale shortwave trough tracking eastward across the Central Plains. Within the heart of this thunderstorm complex, radar estimation and a handful of automated gauges that especially parts of Valley County (including Ord) picked up a quick 0.50-1.00" of rain. Meanwhile, only a few spotty lighter drifted through mainly some of our southwestern zones overnight, as again, most places have stayed dry. At the surface, the pattern/pressure gradient is pretty weak, keeping winds light (mainly under 7 MPH), thus far from various directions but should eventually trending more consistently north-northwesterly getting later into the morning. Under a decent amount of mid-high level cloud cover, most of our CWA appears on track to see lows bottom out 60-63. Although not expected to be a widespread concern by any means, would not be shocked to see a little patchy fog try to develop yet this morning (not in our official forecast), but the cloud cover is likely one factor holding this potential back a bit. - TODAY (through around 7 PM): While not necessarily a "perfect day" by any means, first and foremost take advantage of the seasonable temperatures to get outside for work/play if you can, because the heat cranks up after today. In the big picture of the mid-upper levels, the aforementioned upper wave will gradually depart to our east today. And while most areas will likely stay dry under partly-mostly cloudy skies, we have at least slight (20%) chances/PoPs for spotty showers/weak thunderstorms across our entire CWA for at least part of this morning (higher chances north of I-80 in closer proximity to the very slow-moving MCV), and then a continuation of slight chances for showers/isolated thunderstorms this afternoon mainly for counties along/east of Highway 281. While most areas will surely be dry this afternoon (hence only slight chances), the combination of seasonably-modest-but-evident instability/CAPE of around 500-800 J/kg during peak heating, in combo with modest deep-layer shear around 30KT and residual lift on the very backside of the departing wave, COULD spark off a few "sneaky" stronger thunderstorms that would track northwest- to-southeast through some of our east and especially northeast counties. Should this occur, small hail/gusty winds certainly a possibility, but again, on a very isolated basis. Backing up to this morning, although flooding is not a big concern by any means, some localized "bullseyes" of around 1" of rain probably cannot be ruled out mainly in our northern counties from the slow-moving/regenerating showers/weak storms occurring near the MCV. In other departments today, nudged up high temps a degree or two from previous, with most areas aimed low-80s but more mid-80s south and southwest. Not accounting for any localize influences from shower/storm outflow, breezes today will be fairly light...generally around 10 MPH out of the north-northwest. - THIS EVENING-OVERNIGHT (beyond 7 PM): Have maintained a dry forecast, as any spotty showers/storms that might be in our east-northeast counties late this afternoon-early evening are expected to fade away and/or depart by 7 PM. This should make for a pretty pleasant evening under mostly clear skies. Winds this evening will become very light/variable in direction, then turn light southerly overnight. As with daytime highs, tonight`s lows will also be the coolest we`ll see for a while, with most areas forecast to drop to around 60, and even some upper 50s especially far north-northwest. - THURSDAY-THURS NIGHT: Overall high-confidence in our going dry forecasts upper-level high pressure/ridging centered to our south over the Southern Plains becomes our dominant influence aloft. That being said, there are at least subtle hints (mainly ECMWF) that some thunderstorm activity could TRY developing into mainly our northern zones Thurs night. However, higher-res/short term models largely dismiss this and focus potential convection at least slightly off to our north-through-east where mid-level temps will be a little cooler/less capped. Speaking of temps, Thursday starts our heat ramp-up, and this latest forecast has nudged up highs a few more degrees (most of the CWA 92-97). However, heat index should hold under 100 for one last day. Thursday also kicks off our string of breezy-to- windy days, with southerly speeds sustained at least 15-20 MPH/gusts 25-30 MPH mainly during the afternoon. Low temps Thurs night will easily hold up 10-12 degrees warmer than Wed night (most places low 70s). - FRIDAY-SUNDAY (hot, dry and windy for June): Have already touched on the heat situation plenty above, and yes it gets hot EVERY summer, but that FIRST multi-day round of temps and/or heat index 100+ degrees is always a bit more concerning given that we`re not acclimated to it. In the mid-upper levels, the center of the sprawling upper level high/ridge will gradually migrate northeastward from the Southern Plains to the heart of the eastern U.S. over the course of these three days, while off to the west a large-scale trough gradually builds into the western U.S. However, at least through Sunday daytime, any influence of that trough should remain far enough west (and with very warm mid level temps/capping overhead), to shunt any rain/thunderstorm chances well to our north. While Sunday MIGHT be SLIGHTLY "cooler" than Fri-Sat (am not necessarily sold on this yet), all 3 days look downright hot with actual high temps Fri-Sat mainly 100-105 and Sunday possibly "only" mid-upper 90s. Fortunately, it won`t be super- humid (dewpoints 50s-60s), which will keep heat index in check, but still with widespread 100-105 and localized slightly higher. While highs Fri-Sat could at least flirt with official daily records in Grand Island/Hastings, it`s actually more likely that daily records are threatened for WARM OVERNIGHT LOWS, with most of the CWA forecast to drop no cooler than mid-upper 70s. Depending on your particular situation/perspective, the seasonably-windy conditions each afternoon with gusts commonly 30-35+ MPH could provide some relief, but also accentuate that "blast furnace" feel. - MONDAY-TUESDAY: Although confidence is still plenty low in the details at this Day 6-7 range, in theory we see a return of thunderstorm chances (potentially decent chances and perhaps some severe threat?) as weak disturbances riding along the southwest-northeast oriented interface between the eastern U.S. ridge and western U.S. trough provide some upper lift into our region and diminish mid-level capping, while at the surface at least a weak cold front should sink southward toward/into our area, dialing back the heat toward more tolerable levels. At least for now, we`re aiming Monday highs mostly upper 80s-low 90s, and Tuesday mostly 80s, but much will depend on exact frontal position, precipitation trends etc. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 600 AM CDT Wed Jun 18 2025 For KGRI/KEAR Airports: - General overview (including winds): High confidence in VFR ceiling/visibility and rain/thunderstorm- free conditions through at least the vast majority of the period. However, especially these first 3-4 hours will feature a chance for a few passing showers/weak thunderstorms (mainly at KGRI), and also some continued "sneaky" development of low clouds (MVFR/IFR). Wind-wise, aside from any possible brief enhancement from convective outflow (gusts 15-20+KT certainly possible should this occur), prevailing speeds should largely hold at-or-below 10KT, with direction predominantly out of the north-northwest today and then variable-becoming-southerly tonight. - Ceiling/visibility/precipitation details and uncertainty: Right out of the gate early this morning KGRI is very near an area of showers/weak thunderstorms centered 10-20 miles north, while KEAR is farther removed from this convection but is also reporting at least brief/transient IFR ceiling. For KGRI, have a PROB30 group through 16Z to cover the continued possibility of a few showers/weak storms passing through, while at KEAR kept out any formal -TSRA mention but did run a TEMPO through 15Z to cover the MVFR/IFR ceiling potential. Beyond these very short- term concerns, confidence is very high in VFR this afternoon through tonight as skies clear. It`s not out of the question that KGRI could see a very isolated passing shower/thunderstorm this afternoon, but this is a low enough probability that felt even a PROB30 could not be justified. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Pfannkuch AVIATION...Pfannkuch