DISCUSSION
Issued at 200 PM CDT Fri Jul 26 2024

Quiet midsummer weather continues at midday, with a continued clear (albeit milky and smoky) sky across SW KS, courtesy of a positively tilted ridge axis over the plains. Few if any clouds through this afternoon in a strongly subsident regime. Lee troughing deepening to near 1000 mb over eastern Colorado will support south wind gusts to near 30 mph through sunset, especially west of Dodge City. Typical late July temperatures in the low to mid 90s will prevail.

The ridge axis weakens further Saturday, as the core subtropical high over Arizona temporarily weakens, and as a weak disturbance tracks north into southeast Kansas. Westerly momentum across the Rockies will remain sufficient to strengthen lee cyclogenesis down to 996 mb across eastern Colorado Saturday afternoon, supporting a continuation of elevated south to southeast winds.
Gusts of 30-35 mph are expected, particularly along the preferred US 83 corridor (Scott City to Liberal) Saturday afternoon. Models show little if any thermal changes at 850 mb, such that Saturday afternoon temperatures will remain near late July normals, in the lower to mid 90s.

Weak shortwave over eastern Kansas 7 pm Saturday will eject northeast into the upper Mississippi valley Sunday, clearing the way for the core subtropical anticyclone to begin expanding across the plains with rising heights over SW KS. Given a warmer atmosphere aloft, a more SWly downslope compression with continued good winds/mixing, and models spreading 850 mb temperatures > 30C into SW KS, noticeably hotter afternoon temperatures within a few degrees of 100 will result Sunday.
GEFS ensemble probability of temperatures > 100 are near 100% across the northwest zones, northwest of DDC, where temperatures will reach the 102-104 range Sunday.

The core of the expected heatwave will occur Monday through Thursday, with several consecutive afternoons of 100+ degree heat expected. Triple digit heat is guaranteed, with GEFS/EPS ensembles showing 100% probability of temperatures > 100, all zones, for all days Monday through Thursday. The thinking is record breaking heat (109-111 range) will be difficult to achieve, given 1) SW KS will reside only on the northern periphery of the subtropical ridge much of this time, and 2)
widespread green vegetation and associated evapotranspiration will act to hold temperatures down a few degrees. A relatively dry heat (dewpoints in the upper 50s and lower 60s) is expected, reducing heat impacts somewhat, but the persistence of the heat for several days will take a toll on agriculture and livestock production, as well as those working outdoors.

Rain chances will be near zero for SW KS for the duration of this synoptic pattern. There may be an isolated thunderstorm near Hays Sunday evening, perhaps northeast zones again Tuesday evening, but pops for these are necessarily very low (<15%).
ECMWF/EPS ensembles do show the subtropical ridge retrograding westward back toward the Four Corners around August 1, and the resultant NWly flow may allow for a weak cold frontal passage and a return of scattered convection next Thursday.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
Issued at 620 PM CDT Fri Jul 26 2024

VFR flying conditions are likely this TAF cycle for all terminals, with persistent wildfire smoke maintaining the possibility of brief drops into MVFR vis at any terminal. Wind forecast will follow its typical diurnal cycle, with breezy south to south-southeast winds continuing for the next hour or two, weakening to aob 12 kts through the overnight and early morning periods, and re-intensifying mid-morning Saturday into the 15-20 kt range with gusts of 25-30 kts possible through 00Z Sunday.

DDC WATCHES/WARNINGS/ADVISORIES
None.