Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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043 FXUS63 KGID 031112 AFDGID Area Forecast Discussion National Weather Service Hastings NE 612 AM CDT Wed Jul 3 2024 .KEY MESSAGES... - A few isolated to scattered showers/non-severe storms may make their way into portions of the area through the first half of the day, mainly along/south of I-80. - Better chances for thunderstorms come in two rounds this evening and overnight. The first, tied to a complex sliding southeast this evening, will have the best potential for strong-severe storms, especially west of Highway 281 in Nebraska as well as across north central KS. Large hail and damaging wind gusts look to be the primary threats. - The second round of storms later tonight, tied to the arrival of the main upper level system, is expected to arrive closer to/after roughly 3 AM. While some stronger storms will be possible, the overall threat for severe weather should be diminished. - Storm chances will continue on into the day on Thursday/Independence Day, but are expected to end by mid-late afternoon...with the evening/fireworks activities expected to be dry. && .DISCUSSION... Issued at 423 AM CDT Wed Jul 3 2024 Currently... Been an overall quiet night so far across the forecast area, with mostly clear skies. Looking aloft, upper air and satellite data showing west-southwesterly flow in place across the region...set up between broad troughing spread across much of Canada and high pressure centered over the Gulf Coast region. At the surface, weak high pressure settled across the area is keeping winds light/variable, with frontal boundaries located both to the SE and NNW of the forecast area. Though it`s been dry overnight (which many locations needed after recent heavy rains)...an area of scattered showers and thunderstorms is currently extending from east central CO southeastward into south central KS. This activity is being driven by increased lower level warm air advection/convergence and more subtle forcing aloft...and has ever so gradually drifting north with time. Expecting mid-upper level cloud cover to increase through the rest of the early morning hours...but some models still showing the potential for some spotty fog. The mostly clear skies and light winds have allowed temps to drop into the 50s in some location across south central NE as of 3AM...with lower across north central KS. Today into Thursday/Independence Day... Looking at the daytime hours today...models continue to show some differences with this ongoing activity to our southwest, and how much makes it far enough north to affect our forecast area. The overall best chances look to remain over portions of KS closer to/south of I-70, but kept some 30-40 percent chances across our KS counties in the 12-18Z time frame. One change was to add some 20 percent chances further north, spread through counties along I-80...not great chances for measurable precip, but hi-res models showing the potential for at least isolated activity to push east through the morning. Not expecting any severe weather with any of this activity. Through the day, models continue to show the next upper level disturbance to impact our area sliding southeast out of western Canada and through the Nrn Rockies. Ahead of this disturbance, expecting surface low pressure to deepen over the High Plains, while the area of high pressure pushes to our east. As a result, the current light/variable winds will be switching to the SSE with time, and while speeds won`t have an significant increase (10-20 MPH from east to west), gusts closer to 20 MPH will be possible this afternoon, mainly for areas west of HWY 281. By mid-late afternoon, a surface frontal boundary become more well defined over western Nebraska...with thunderstorms expected to fire along it as that upper level disturbances moves in. The big question the becomes...what will the impact be on our forecast area? Unfortunately there are still some notable differences between models with just how well things hold together as the complex push southeast. Different runs of different models have gone back and forth between activity diminishing notably before getting here to a mature MCS having little trouble moving in...so hard to have a high amount of confidence. Forecast reflective more of the models showing an MCS moving into western portions of the forecast area early this evening...but its strength as it makes eastward progress is in question, as models continue to show the main axis of better instability (lower level and elevated) bring more focused over western NE/KS, perhaps into western portions of the forecast area. Deeper layer shear remains sufficient for strong to severe storms to be a concern, it`ll just be a matter of instability present...which its return northward through the day today could be inhibited by the convection that will be crossing KS. There are a number of `gonna have to see how things evolve` details with the forecast for later today/this evening. Roughly the western half of the forecast area remains in the SPC Slight Risk area...with the rest of the area in the Marginal Risk area. Large hail, damaging winds, heavy rain look to be the primary concerns. Another complicating factor in the forecast as we get into the overnight hours is that we may end up getting two separate rounds of activity moving through the area, with a little bit of a lull in between. The first, discussed above, is tied to that sfc frontal boundary and developing MCS...the second is tied to the mid-upper level trough axis of the main system itself. Activity with its arrival into western portions of the area looks to be closer to the 09-12Z time frame. Think the potential for severe weather would be diminished with the arrival second round. These precip chances then spread east/continue on into the daytime hours on Thursday, with models showing the upper level system evolving into a closed low as it slides east across SD. Timing between models hasn`t changed significantly...still looking at the main precipitation chances being through the first half of the day, pushing east of the forecast area by mid-afternoon. At this point the better chances for any severe weather look to focus east of the forecast area. Have the late afternoon/evening/fireworks hours dry area-wide. Outside of the precipitation chances, this upper level system will push a cool front through the area...ushering in potentially breezy northwesterly winds, which should diminish in the evening. Following high temperatures today expected to be in the low-mid 80s, highs for Thursday look to be in the mid 70s-near 80 from north to south across our Neb. counties, with low-mid 80s across our KS counties. Friday on into the new work week... Models remain in good agreement showing a pattern change by the time the end of the week rolls around, at 12Z Friday showing the upper level low over MN/WI with its southward extending trough axis, while a ridge axis extends north along the West Coast. This more northwesterly upper flow looks to remain in place through the end of this 7-day forecast period...with the main concern then being any potential shortwave disturbances passing southeast through the Plains. At this point models are in ok agreement with the on Friday being dry, and while evening/overnight hours are currently dry in the forecast, will have to see how models trend with the timing of a couple of waves looking to move into the region. Forecast currently focuses the better chances on Sat/Sun, drying back out Mon/Tue. Hard to have a high degree of confidence in the timing/path of these disturbances the further out in time you go. As far as temperatures go, upper 70s-mid 80s are forecast for Friday, with mid 80s-low 90s on Sat and 70s/80s for Sunday...but how the timing of any precipitation chances end up panning out could throw a wrench in those weekend highs. Mainly 80s currently forecast for Mon/Tue. Normal highs for this time of year are mid 80s north to right around 90 in the south. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 607 AM CDT Wed Jul 3 2024 For KGRI/KEAR Airports: Can`t rule out some patchy fog in the area early this morning, but the better potential for sub-VFR conditions looks to be in the final few hours of this period, which has MVFR ceilings. There will be some isolated to scattered showers/storms moving through this morning, but confidence in any impact at the terminals was low enough at this time to keep out any mention...better chances will be to the south. Better chances for storms arrive mid-late evening then again toward the end of the period, and a VCTS mention both times. Light/variable winds early this morning turn more southerly with time, with speeds increasing to around 15 MPH. A few gusts closer to 20 MPH are not out of the question this afternoon, especially at KEAR. Light/variable winds return later this evening/overnight. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...ADP AVIATION...ADP