Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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789 FXUS63 KGID 182326 AFDGID Area Forecast Discussion National Weather Service Hastings NE 626 PM CDT Wed Sep 18 2024 .KEY MESSAGES... - There could be a few (<20% coverage) thunderstorms mainly east of Hwy 281 this evening (5-11PM). A marginally severe storm is possible (5%). - Warm and dry most areas Thursday and Friday with highs still in the mid to upper 80s. - Showers and thunderstorms move into the region Friday night and especially Saturday into Sunday with widespread rainfall amounts over 1 inch. - Cooler next week with highs only in the 60s for many areas Sunday through Tuesday. && .DISCUSSION... Issued at 326 PM CDT Wed Sep 18 2024 This Evening into Tonight... We have a large upper level trough across the western United States with two 500 mb low centers. The first upper low is well to our north over Montana/North Dakota with an associated surface front extending from the Dakotas south into Nebraska and Kansas. This is really more of a dry line across our area with better moisture to the east and dry high plains air to the west. The 2nd upper low is just about to come ashore over California and will be our weekend storm system. The track of this first system well to our north (North Dakota) is not providing us with much forcing and thus any showers and thunderstorms within the moist sector will be rather isolated. However, the SPC marginal risk does highlight a valid risk for the possibility of a few severe thunderstorms given MLCAPE values inching up over 1500 J/KG and 0-6 km shear values of around 30-35 KTS. Most convective models indicate that any thunderstorms would likely be rather isolated so again are expecting most locations should remain dry tonight. The best chances for catching one of those isolated storms will be east of Highway 281. Thursday and Friday... Drier air will push in from the west on Thursday behind the departing first wave with northwesterly surface winds. Therefore, dry and warm weather with highs in the mid to upper 80s are expected on Thursday. The next upper low will slowly be tracking east across southern California on Friday with return southerly flow starting to take hold across the southern and central plains ahead of this next system. We will see rising dew points, but any rainfall should likely hold off until late evening or overnight beginning first in Kansas and then working north through the Friday late night hours. Saturday and Sunday... This appears to finally be the big rain that so many have been waiting for, just too bad that it`s on a weekend. The latest 12Z ECMWF ensemble average indicates over 1 inch of precipitation for our entire forecast area with a 2 inch average across some of our eastern counties. The GFS is also bullish with precipitation this weekend. The brunt of the precipitation will be Saturday afternoon through Sunday morning, but light precipitation could linger through much of Sunday. There does not appear to be much instability with this system so severe weather is not much of a threat at this point in time. Can not rule out localized flooding if we see some localized higher amounts over 3 inches, but it has also been very dry lately. Temperatures will start to fall on Sunday on the back side of this next system with northwestern areas likely only in the 60s. Monday and Tuesday... We should dry back out and become more fall like with most highs only in the 60s to around 70. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 625 PM CDT Wed Sep 18 2024 For KGRI/KEAR Airports: Significant weather: None. Tonight: Ongoing SCT clouds around 4-5K ft should dissipate by around midnight. There`s a very slim chance for an iso storm to pop up next few hrs at mainly GRI, but odds just too low to include at this time. Steady S winds 7-10kt should go lgt and vrbl with the approach of a cold front by around dawn. Confidence: High. Thursday: Cold front will cause lgt and vrbl winds to swing to the NNW around 14-15Z. Some guidance suggests some FEW-SCT stratocu around 1500ft for a few hrs immediately behind the front, with chcs slightly higher towards GRI than EAR. Otherwise, skies will be mostly clear by midday with steady/brzy NNW wind continuing thru the aftn. Confidence: High. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Wesely AVIATION...Thies