DISCUSSION
Issued at 510 AM CDT Fri Sep 20 2024

-- PRIMARY CHANGES WITH THIS 7-DAY FORECAST PACKAGE VERSUS THE PREVIOUS ONE ISSUED THURS AFTERNOON:

- Small (mainly 20%) thunderstorm chances have been added to most of our CWA (but especially southeast half) for the pre- midnight hours this evening (previous forecast held off any chances until post-midnight). The Marginal Risk of severe from SPC (level 1 of 5) in especially our southeast 1/3 is also new.

- Unfortunately for those really wanting significant/soaking rains this weekend, Sat-Sun cumulative rainfall totals are on a downward trend, with generally our northwest 1/2 now expected to top out mainly in the 0.50-1.00 range, and our southeast half more so 1-2, but with dwindling potential for anything over 2 except for maybe in our extreme southern KS zones.

- Looking well into next week, high temps for the Tues-Thurs period have trended up a good 2-4 degrees from previous forecast (still mainly 70s, but more so mid 70s versus lower 70s...especially Wed-Thurs). All things considered, from an early fall weather enthusiast/comfort standpoint, Mon-Thurs are really looking quite pleasant!

-- 7-DAY FORECAST OVERVIEW/DETAILS:

- UP FRONT ADMIN NOTE: First 7-day forecast shift in a while for this forecaster, so between familiarizing with the latest trends and some ongoing behind-the-scenes communication outage challenges (thanks for the assist OAX!) will be keeping these paragraphs a bit more generic than usual...

- CURRENT/RECENT WEATHER SCENE AS OF 430 AM: Its been a dry and tranquil night/early morning, as the combo of a mix of clear skies/thin high cirrus aloft and high pressure at the surface (promoting extremely light/near-calm winds) has overnight low temps on track to bottom out mainly low-mid 50s north to upper 50s-low 60s southeast (although its quite likely typical cooler spots such as Ord could easily slip into the upper 40s). In the big picture aloft, a big/closed low pressure system is still way off to our southwest, centered just off the southern CA coast.

- TODAY DAYTIME: Maintained a dry forecast CWA-wide through at least 00Z/7PM, with a mix of mostly sunny/partly cloudy skies under variable coverage of high cirrus drifting over. The big story will be ONE LAST day of truly well-above average warmth, with all areas aimed a few degrees either side of 90. As surface high pressure departs east, especially this afternoon will feature breezy south-southeast winds generally sustained 10-15+ MPH/gusts 15-25 MPH.

- THIS EVENING-OVERNIGHT: Although MOST places will likely remain dry as the main/large- scale upper level low pressure system remains well to our southwest over AZ, the combo of weak disturbances lifting out ahead of the main low, along with convergence along the nose of a south-southwesterly low level jet will likely promote at least isolated to perhaps scattered showers/thunderstorms this evening-overnight, particularly after 10 PM. While most of our CWA stands at least a small chance, the overall highest chances should focus within our southeast 1/2, much of which has now been assigned a Marginal Risk of severe from SPC. Despite the expected spotty coverage, hard to totally dismiss the Marginal Risk given what should be at least 1000-1500 J/kg of elevated CAPE and 30-40KT of deep layer shear (a few storms capable of producing hail to around quarter size/winds to around 60 MPH).
Low temps ranging from upper 50s-mid 60s northwest half to mid- upper 60s southeast half.

- SATURDAY DAYTIME: By late in the afternoon, the big upper low should reach southwestern CO area. However, here at home, and leaning closely on latest HRRR/NAMNest higher-res models, especially most areas north of the KS border will probably stay dry much of the day, and rain chances/PoPs have trended down somewhat. Of any storms that do form, probably cannot totally rule out severe, but the main threat for marginal severe should focus slightly east of our CWA (per SPC Day 2 Marginal). High temps will be fairly tricky as a well-defined cold front drops down from the north, but for now have highs aimed from mid-upper 70s northwest to mid-upper 80s southeast.

- SATURDAY NIGHT-SUNDAY NIGHT: Although cumulative rain amounts have trended downward (see above), these 36 hours are still expected to feature fairly widespread rain/showers with embedded, mainly weak thunderstorms, as the aforementioned strong upper low over the Rockies slowly/gradually approaches and passes directly overhead our local area. Rain amounts of at least 0.50-1.00 should be fairly widespread, but anything over 2 is now looking to be more of a localized exception and favoring far southern counties.
Temp-wise, while Sunday will CERTAINLY be the overall-coolest day of the next 7, just how cool will depend on how widespread clouds/rain actually are. For now though have most areas aimed 56-60, with lows Sunday night ranging low 40s west to upper 40s east.

- MONDAY-TUESDAY: Although probably cannot totally rule out some spotty rain, our official forecast is dry CWA-wide as we remain in between systems (especially per ECMWF). High temps start to rebound, aimed mainly mid-upper 60s Mon and low 70s Tues.

- WEDNESDAY-THURSDAY: The dry forecast continues as both ECMWF/GFS suggest at least weak ridging aloft to be the dominant influence. Although not a major change by any means, high temps have bumped upward (more so mid 70s than lower 70s), with overnight lows creeping back up more into the low 50s than 40s.



AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
Issued at 1228 PM CDT Fri Sep 20 2024

VFR conditions are expected. Winds will be out of the south to southeast this afternoon with gusts around 20 knots. Winds will decrease this evening and will be out of the southeast to south. Westerly to northerly winds are expected around 15z as a cold front moves into the area. Winds may gust up to around 25 knots out of the north at 18z Saturday.

GID WATCHES/WARNINGS/ADVISORIES
NE...None.
KS...None.