Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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225 FXUS63 KGID 301043 AFDGID Area Forecast Discussion National Weather Service Hastings NE 543 AM CDT Sun Jun 30 2024 .KEY MESSAGES... - Another seasonably cool day today with some areas of showers/weak storms. - Much warmer and more humid for the start of the new work week. Areas along and south of the state line will likely experience heat indices into the low 100s Monday, and perhaps again on Tuesday depending on timing of a cold front. - Elevated thunderstorms will bring potential for marginally severe hail late tonight into early Monday morning, but greater risk of more significant severe storms will come late Monday afternoon into the evening and overnight. - Semi-active pattern will continue through much of the week thanks to series of fronts and weak disturbances. This could mean off and on thunderstorms on and around the 4th of July holiday. Daily highs will tend to favor near to just below normal levels in the 80s to low 90s. && .DISCUSSION... Issued at 520 AM CDT Sun Jun 30 2024 Much quieter conditions in place compared to 24 hours ago as skies are mostly clear and temperatures are fairly cool in the 50s to low 60s. ODX may even touch the upper 40s prior to sunrise. Great opportunity to open the windows and give the AC a break! The dry/quiet weather will be short-lived, however, as showers and weak storms associated with mid level warm air advection over S KS are still forecast to lift N towards the KS/NE state line by around midday. This activity is forecast to weaken some with time and NEward extent this afternoon, but would think at least sprinkles would be possible for most areas through 4-6PM. Latest HRRR runs have trended more aggressive with today`s rain chances, and thus have trended cooler on high temps - particularly W of Hwy 281 where rain and thicker clouds look to be most prevalent/widespread. Taken verbatim, areas along Hwy 183 corridor could struggle to get into the low 70s, so was most aggressive in trending highs cooler for these areas. Rain amounts look to average around 0.10-0.30" from the Tri- Cities S and W, with locally higher amounts towards 0.50-0.75" possible along/S of the state line in convective elements. All in all, today has trended rainier for more of the daytime hrs, esp along/S of I-80 and along/W of Hwy 281. Expect a lull in rain chances this evening into the first half of the overnight tonight, but a strengthening and veering low level jet should bring fairly high chances (50-70%) back to majority of south central NE and north central KS after midnight through mid-AM Monday. This activity will have pockets of greater instability (MUCAPE up to 1000-1500 J/kg) and effective shear (30-40kt) to work with, so some marginally severe hail can`t be ruled out in the strongest cores. Most model guidance has majority of rain E of the forecast area by noon Mon. Rain amounts with this round look to be similar to slightly higher than today`s round, though the high end of the localized amounts could be higher in the 1-1.5" range. Once the AM rain exits, focus will quickly turn to much warmer and more humid conditions for the afternoon. Because of the AM rain, highs are somewhat uncertain for areas N and E of the Tri- Cities, but S and W will likely become quite hot as air temps peak in the mid 90s to lower 100s. Models suggest some greater/deeper mixing and lower dew points for these areas, but even mid-upper 60s Tds would still support heat indices several deg higher than the air temps - generally 100-107F, highest in our KS counties. Brzy SE winds will provide at least SOME relief, fortunately. After coordination with neighboring offices the consensus was to hold off on any heat headlines at this time, but wouldn`t be shocked if next shift issued a Heat Advsry for at least our KS counties, esp. Beloit area, as relief Mon night could be limited with lows only in mid-upper 70s. Sfc low pressure is forecast to deepen near the CO/NE/KS border area by late Mon aftn in response to right entrance region of seasonably strong mid level jet streak ejecting from the central Rockies into N Neb. A warm front will arc E/SE from the low, separating a very hot/deeply mixed airmass and very steep low level lapse rates to the S from much more moist and unstable airmass to the N thanks to pooling Tds in the low to mid 70s. Some sort of inverted trough-like feature may extend to the N into the Neb. Sandhills region. Capping will likely be a significant hindrance to convection through most, if not all, of the afternoon thanks to H7 temps around 13-14C. However, subtle height falls associated with weak disturbance in WSW upper flow, along with sustained convergence near the triple point and associated boundaries could be enough to erode the cap sufficiently for vigorous tstm development around 23-00Z. IF the cap breaks, storm development could be fairly explosive given strong instability (MLCAPE 2500-3500+ J/kg) and higher end deep layer shear by early July standards (35-50kt), thanks to aforementioned mid level jet streak. Even low level shear will be enhanced by strengthening low level jet Mon eve, supporting 0-3km SRH values of 150-250 m2/s2. Thus, all severe hazards will be possible, including a few tornadoes and very large hail. Locally intense wind gusts over 70 MPH will also be possible, particularly with any upscale growth Mon eve. Much of south central Nebraska (most likely area to be along/N of warm front) remains in a Slight Risk (level 2 of 5) on latest SPC outlook, with the main limiting factor to an upgrade being questions on capping and overall storm coverage. Could certainly envision an increase to "Enhanced" (level 3 of 5) once mesoscale details become more clear following Mon AM convection. The cold front will likely still be bisecting at least parts of the area, most likely SE of the Tri-Cities, on Tuesday, with areas behind the front cooler in the 80s, but continued hot and humid to the SE for areas like Beloit to Hebron. Another round of strong to severe storms will be possible along and SE of the front by late Tue aftn/eve within environment of moderate instability and continued seasonably strong shear. Shear vectors largely parallel to the cold front and linear forcing suggest mainly hail to high wind threat evolution. Locally heavy rain also possible given short-term training and PWATs 1.6-1.9", or roughly +2 standard deviations above normal. Would think at least a semi-active pattern will continue through the end of the week thanks to zonal upper flow and possibility for Tuesday`s front to stall out near/just S of the area and perhaps even lift back northward sometime Wed into Independence Day. Just too far out to work out specific details regarding timing and placement, however. Of higher confidence is that with the flatter mid/upper flow should be temperatures closer to, or even a bit below, normal...so mainly 80s with perhaps some lower 90s in KS. Certainly can`t rule out some "natural fireworks" for Independence Day celebrations, so those with outdoor interests will need to keep an eye on the latest forecasts. Ensemble precip probabilities tend to drop off some towards next weekend. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1250 AM CDT Sun Jun 30 2024 For KGRI/KEAR Airports: VFR conditions should prevail for most of the valid period, though expect increasing mid to high level clouds throughout the daytime hours today. Could see enough of an incr in low level moisture such that MVFR CIGs move in sometime this evening. Maintained an aftn VCSH at EAR, but appears the vast majority of this high-based showery activity should remain off to the S. NE winds currently will veer to SErly for the daytime hrs, becoming a bit brzy for the afternoon. Confidence: High. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Thies AVIATION...Thies