Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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557 FXUS63 KGID 132350 AFDGID Area Forecast Discussion National Weather Service Hastings NE 650 PM CDT Thu Jun 13 2024 .KEY MESSAGES... - Cold front moving through the area now is leading to broad range in sensible weather - mild, dry and breezy north, to hot and steamy S/SE. - This front will be responsible for low chances (20-30%) of thunderstorms across north central Kansas next few hours, but IF any develop, they may be on the marginally severe side with large hail and strong winds. - Better chances (50-80%) for storms arrive late Friday evening and continues overnight. Large hail and damaging wind are the main concerns. There is a SLIGHT Risk (level 2 of 5) mainly W/SW of the Tri-Cities, and a MARGINAL Risk elsewhere. - Rest of the forecast appears somewhat active with nearly daily shower/storm chances, generally highest (40-50%) mid to late next week. - After a brief/minor cool down for Friday, temperatures moderate by Saturday then become hot again (90s to low 100s) Sunday and Monday. Expect mainly 80s-90s next week. && .DISCUSSION... Issued at 337 PM CDT Thu Jun 13 2024 Rather interesting day out there today from a sensible weather perspective, as conditions range from mild, dry and breezy across central NE, to quite hot and steamy in northern KS. In fact, ODX is in the low 80s, has a sub-60 dew point, and NE winds a refreshing 20 MPH, gusting 30 MPH. On the flip (S) side of the front, areas near Beloit are in the low 100s with dew points in the upper 60s to lower 70s. At least these areas have a breeze, as well, but out of the S. Sfc cold front has made to, or even just S of, the NE/KS state line as of 3PM, and should continue to sink southward this evening. Recent satellite data shows new CU/TCU development along a WSW to ENE axis - roughly near the I-70 corridor. This appears to be ahead of the actual cold front, likely along some sort of pre-frontal trough/wind shift. Hi-res guidance has been pretty consistent in that the main convective development would indeed be just S of the area this aftn/eve, and this seems to be what`s playing out. Have maintained some low end PoPs in our far S (20-30%) in the event the storms grow large enough to clip these counties before moving SE. There have been some very small, iso and elevated cells develop in Lincoln County this afternoon, along what appears to be the lowest 100mb mixing ratio gradient. Hi- res guidance has not handled this activity well, and kept out of the official forecast at this time given recent weakening. Model soundings suggest a narrow corridor of weak instability based above the primary capping inversion, but don`t think this will amount to much given primary upper support shifting away from the area. Current cold front looks to stall out and become more diffuse by late overnight, so the primary MUCAPE axis never really clears the area. In fact, models show weak warm air advection returning to W/SW zones by dawn Fri AM, so wouldn`t be shocked to see some ACCAS and a few "sunrise surprise" storms W/SW of the Tri- Cities. By in large, however, think much of the daytime hrs Fri will remain dry thanks to negligible 500mb height changes and very warm mid level air evidenced by 700mb temps around 12-15C. SE winds should limit the mixing depth and high end potential for temps, but low to mid 60s dew points will return to at least the far W and SW. These higher dew points will also serve as a good proxy of the primary instability axis for storms that develop over the higher terrain Fri aftn to work with as they shift E/NE Friday eve. Latest thinking is that activity will approach far W/SW zones as an MCS around mid to late evening, probably on the strong to severe side. Main threat should be high wind, though some hail could still be possible too. Activity should gradually weaken with time and E/NE extent Fri night as activity "outruns" the aforementioned instability axis. IF this instability axis lines up further NE, or can be advected NE Fri eve, then the severe threat could extend/expand in time/space. One other thing to watch, though is low confidence at this time, is potential for pockets of iso heavy rain. There could be some backbuilding on the SW/S flank of said MCS, and PWATS will be elevated in the 1.5-1.7" range. How prevalent the backbuilding/training actually is is uncertain. Models generally dry us out by dawn Sat AM. Forecast details beyond 48hrs become fairly murky, as they often are in the summer months, due to effects of convection, the weakest of upper level disturbances, and potential boundary placement. The NAM suggests mostly uncapped moderate to strong instability late Sat aftn and into the eve, along with modest deep layer shear of 25-35kt. Main question is forcing and upper level support as some of the guidance show a filling shortwave over the N Plains, shifting away from the area by 21Z, whereas other guidance lingers at least weak height falls later and further SW. SREF guidance suggests the best instability axis may lag the better shear, which makes sense given the overall setup. The Marginal Risk on the SPC Day 3 Convective Outlook seems reasonable enough to cover a low-confidence, non-zero chance for severe weather Sat PM...though would expect this to be refined and/or shifted over the coming updates. SREF calibrated guidance would support slightly higher probs over E/NE zones vs W/SW. Should get into a drier and hotter pattern for a couple days Sun-Mon, with some areas along/S of the state line likely nearing or exceeding triple digits for highs once again. May be pushing Heat Advisory conditions for these areas one or both days. Would think H7 temps in excess of 15C would keep us capped off and dry, esp. Mon, but stranger things have happened. More coherent upper level troughing and push of lower mid level temps/heights should arrive around the middle of next week and perhaps linger in the region through the end of the week. This could make for a pattern of repeated rounds of convection and more mild high temps for the second half of next week. Multiple ensemble platforms support this idea by showing above normal precip anomalies and above normal temperature anomalies (likely driven by warm overnight lows) through the region next week. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 642 PM CDT Thu Jun 13 2024 For KGRI/KEAR Airports: VFR conditions are expected at both terminals through the forecast period. Expect a mix of a few high clouds and maybe a few low clouds through most of the forecast. East-northeasterly winds remain breezy for a few more hours, decreasing around sunset. Winds will become easterly after sunrise tomorrow morning, increasing to around 10-15kts from the southeast by mid-day. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Thies AVIATION...Wekesser