Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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013 FXUS63 KGLD 211726 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 1126 AM MDT Fri Jun 21 2024 .KEY MESSAGES... - Continued very windy today with 20%-30% chances for afternoon and evening thunderstorms, mainly along/north of I-70, some of which could become severe(Yuma/Dundy/Hitchcock counties). - Weekend looks to remain hot with highs in the 90s. Could be a few thunderstorms Sunday afternoon/evening. - Hottest temperatures of the period Monday/Tuesday. Heat index values of 100-105 degrees east of Highway 25. - Not as hot (highs in the 90s) Wednesday/Thursday with better chances (20%-40%) for thunderstorms moving through the area from the west during the late afternoon to overnight hours. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 312 AM MDT Fri Jun 21 2024 Across the region this morning, skies are mainly clear, except for lingering clouds north from exiting precip, and some mid/high clouds over southern portions of the area. As of 100 AM MDT, temperatures are ranging in the 60s and 70s. With a surface low sitting off to the southwest of the CWA, and a front sitting over the extreme northern portion of the area, persistent southerly flow is occurring for most. Areas along/north of Highway 34 are seeing an easterly fetch in the vicinity of the boundary. Weather concerns for the short term period will focus on the hot conditions each day with above normal temperatures, strong southerly flow over the area today/tonight and the threat for showers and some thunderstorms(some may be strong to severe for portions of the area later today/this evening). Currently for today/tonight, the latest RAP40 500mb analysis and mid level water vapor imagery are showing a broad elongated ridge over a good portion of the eastern U.S. and with the western extent of this ridge extending into central/southern Plains, the Tri State area is seeing SW flow aloft. The aforementioned surface low sitting over eastern Colorado will shift eastward through the afternoon/evening hours, combining with a shortwave that works over the western/northern periphery of the upper ridge, and will trigger chances for convection with about 15-20% chance near I-70 and increasing to about 30-40% from Highway 36 and points north especially NW zones. The remnant front to the north will also aid in focusing convection as the entire complex lifts E/NE later this afternoon into the evening hours. SPC is carrying a Marginal Risk for severe storms for Yuma county in Colorado extending east into Dundy and Hitchcock counties in Nebraska. Best instability will be located closest to the front/low combo, but with daytime heating drying out lower levels ahead of expected activity later today, guidance is having inverted-v soundings around the 21z-03z timeframe, giving DCape values 1000-1400j/kg on top of PW values that increase form an inch in the west to around 1.5" in the east. While hail can`t be ruled out with any storms that do develop, wind could be the main threat along with locally heavy rainfall. Bulk of activity will clear the CWA by 06z Saturday per latest CAMs, with some scattered showers thereafter through 12z Saturday. Before seeing an increase in convection, the southerly gradient ahead of the low passage will afford the area gust potential into the 40-50 mph range by midday into the evening hours, tapering off from west to east as the flow shifts to the northwest. Guidance continues to shift the upper ridge westward into the upcoming weekend, allowing for SW flow aloft to become zonal both days. Dry conditions are expected to persist over the area Saturday, with a weak shortwave passage on Sunday. This system will track east over the northern extent of the ridge. 15-20% pops for isolated rw/trw over western areas during the day, tapering off over NW Kansas during the evening hours. Other than these storms chances, hot weather will persist area-wide. For temps, highs today will range in the lower to mid 90s. On Saturday, upper 80s to mid 90s are expected, and for Sunday, a range mainly in the upper 90s with a few spots around the 100F mark. Heat indices for the most part will range at or below forecasted highs, however, on Sunday a few spots east of Highway 25 will start to see readings approach the low 100s. Overnight lows tonight will range mainly in the 60s west of Highway 83. East of there, upper 60s through the mid 70s. Lower to mid 60s Saturday night will give way to mainly mid to upper 60s on Sunday night. Some locales across Graham and Norton counties will only drop to around 70F. && .LONG TERM /MONDAY THROUGH THURSDAY/... Issued at 250 AM MDT Fri Jun 21 2024 Mon-Tue: Long range guidance indicates that the Tri-State area will be situated on the northern periphery of a broad, west- east elongated ridge (centered over the Desert Southwest, Southern Plains and Lower MS River Valley).. at the southern fringe of the mid-latitude westerlies. Above average temperatures are likely. In such a regime, precipitation chances will largely be tied to the development (and downstream propagation) of diurnal convection emanating from the Colorado Front Range and Palmer Divide.. augmented (perhaps) by small amplitude waves on the southern fringe of the westerlies. Wed-Fri: Long range guidance indicates that the aforementioned upper ridge will consolidate/amplify over the Desert Southwest and extend northward to the 4-Corners and central Rockies (Wed- Thu).. then flatten and regress southward to the Desert Southwest/Southern Plains (Fri).. as an upper level trough progresses eastward ashore the Pacific Coast and cyclonic flow aloft envelopes the Intermountain West. Above average temperatures are apt to persist. In such a regime, precipitation chances /convective development/ will highly depend upon the evolution of the ridge. -- At present -- guidance suggests that the magnitude, position and orientation of the ridge will be such that (1) synoptic subsidence may largely suppress diurnal convective development along the Colorado Front Range/Palmer Divide and (2) that low-level forcing/moisture may be insufficient for in-situ convective development on adjacent portions of the High Plains (i.e. northwest KS). In this pattern, at this range.. convective forecast confidence is below average. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1117 AM MDT Fri Jun 21 2024 Generally VFR conditions will be observed at both KGLD and KMCK, but strong winds, made worse with storms this afternoon and evening, will make for some tricky conditions. Models are having a difficult time figuring out exactly what is going to happen over the next 8 hours, but we are currently expecting two waves of storms. The first will form around 21Z and move away from the TAF sites by 0Z. The second wave, the wave with higher confidence, will impact KGLD around 1Z and should stay south of KMCK. This second wave is expected to produce strong winds as it progresses eastward. If any of the stronger cells moves overhead of either TAF site, heavy rainfall will reduce visibility significantly. The heavy rain is the only concern for IMC throughout the period. Later in the period, winds will weaken and become northwesterly. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...JN LONG TERM...BV AVIATION...CA