DISCUSSION
Issued at 425 PM CDT Thu Sep 19 2024

Tonight through Friday...

Winds will become nearly calm tonight as a surface high rests over our forecast area. Clear skies initially this evening will give way to increasing high clouds by late tonight into Friday ahead of the strong upper level low swinging through the desert southwest. Friday will remain warm (mid to upper 80s) with return southerly flow as the surface high slides east and we see pressure falls across the high plains ahead of the next upper trough. Currently believe that any precipitation chance should hold off until after midnight Friday night and then favor our southeastern zones.

Weekend Rain Still On Track But Amounts Have Come Down Some...

The strong upper low is projected to track northeast into Colorado on Saturday and we expect increasing showers and thunderstorms out ahead of this system especially by late afternoon into the evening hours. However, forecast models are backing off of some of the higher 2 plus inch rainfall amounts from a few days ago. The 9/19 12Z ECMWF ensemble average precipitation amount came in lower for the second day in a row now indicating on average 0.75 inches across our northwestern zones to 1.75 inches across our southeastern zones. We will probably have some locations that get less than a half inch out of this system. The 12Z GFS and ECMWF runs both came in with lower precipitation amounts than yesterday and last night. At this point it seems like most areas from the Tri- Cities and locations to the south and east are still in good shape to pick up weekend total rainfall amounts of 0.75 to 1.5 inches with some locally higher amounts over 2 inches still possible. Locations northwest of the Tri-- Cities now seem like they will be a bit lower. Am not expecting severe weather this time as instability will be lacking.

Timing of the weekend rainfall favors the Saturday late afternoon and evening hours through Saturday night into Sunday morning.
Saturday should still be a pretty warm day for most locations ranging from the mid 70s northwest of the Tri-Cities to the 80s from Hastings and Grand Island east and south. However, it will be a cool rain on Sunday with our expected highs now being lowered into the mid 50s in the Tri-Cities to maybe around 60 over north central Kansas.

Monday through Thursday...

The upper low will pass off to our east allowing for subsidence and drier conditions. We will also be fore fall like with highs generally in the 60s to lower 70s.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
Issued at 1256 AM CDT Fri Sep 20 2024

For KGRI/KEAR Airports:

- Ceiling/visibility/precipitation/thunderstorm potential: High confidence in VFR ceiling/visibility through the period, with the majority of it featuring only varying degrees of high level cirrus. There is also high confidence that at least the vast majority of the period will remain rain/thunderstorm-free (especially the first 21 hours). However, there are hints toward the very end of the period Friday evening (03-06Z) that isolated thunderstorm activity could develop over the general area. IF this were to occur, a quick bout of hail/gusty winds cannot be ruled out. That being said, the probability of any storms impacting KGRI/KEAR is currently deemed no higher than 10-20%, and thus will refrain from any thunderstorm TAF inclusion at this time.

- Winds: Very light/variable direction winds will remain in place early this morning. Then, Friday daytime will feature a gradual increase in speeds out of the south-southeast, peaking 18-23Z during which time sustained speeds 13-15KT/gusts around 20KT will be common. Finally, speeds will again ease down for Friday evening as direction remains out of the south-southeast.



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