Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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412 FXUS63 KGLD 290024 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 624 PM MDT Fri Jun 28 2024 .KEY MESSAGES... - Widely scattered thunderstorms in northeast CO will gradually track eastward into portions of northwest Kansas and southwest Nebraska late this afternoon and evening. Brief, localized wind gusts up to 65 mph cannot be ruled out in association with any storms. - Cooler this weekend with scattered storms possible during the afternoon and evening hours. - Heat returns Monday with low triple temperatures currently forecasted. && .UPDATE... Issued at 600 PM MDT Fri Jun 28 2024 The Tri-State area remains situated on the northern periphery of a ridge, in modest W (500 mb) to SW (300 mb) flow aloft. While the upper level pattern is analogous to yesterday.. the thermodynamic environment and low-level pattern/flow regime today is less favorable than yesterday. 23Z SPC mesoanalysis data indicates marginal instability (~250-500 J/kg mlcape) over northeast CO and northwest KS. A west-east instability gradient exists over central KS/NE.. with increasing instability with eastern extent from Highway 283 (roughly along/east of a line from McCook to Hill City).. where low-level moisture is richer (65-73F surface dewpoints). With little in the way of synoptic/upper level forcing and very weak low-level flow, convective development will likely be confined to topographically/geographically favored areas (e.g. Palmer Divide, Cheyenne Ridge). While said activity will gradually progress eastward into northwest KS and southwest NE late this aft-eve, environmental conditions do not appear particularly conducive for upscale growth/organization into lines or clusters.. nor downward momentum transport (weak surface to 700 mb flow). Strong to extreme DCAPE (1500-2000 J/kg) will certainly support a potential for brief/localized severe downbursts in association with any convection. With the above in mind, severe weather potential this aft-eve appears to be marginal/isolated in nature.. and brief/localized severe downbursts appear to be the primary hazard. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 243 PM MDT Fri Jun 28 2024 Across the region this afternoon, the area is currently seeing mainly sunny skies with some scattered diurnal clouds north and southwest. With the passage of a frontal boundary, there is currently a northerly flow with gusts up to 20 mph at times. as of 200 PM MDT, temperatures are ranging in the 90s. The main wx concerns in the short term will occur with afternoon/ evening thunderstorms chances, some of which may be strong to severe. With a strong elongated 500mb ridge over the southern portion country, as seen from the latest RAP40 guidance, zonal flow is in place over the central Plains. There is a weak shortwave currently over the central Rockies that will shift east through this evening. This system will ride along the aforementioned front at the surface, with the potential for triggering convection. The latest set of CAMs(HRRR, RAP, NamNest) are showing scattered storms approaching the western CWA by 23z-00z. Regional radar is showing some initiation occurring over central Colorado into the Nebraska panhandle. While some storms could initially be severe, the elevated nature of the expected clouds bases combined with the hot and dry conditions at the surface ahead of approaching rw/trw, could allow for only a wind threat. Soundings are showing this with decent inverted-v profiles and high dcape 1400-1600j/kg as a result. Guidance does show this dropping sharply as the evening progresses with an eastward push of any storms. The latest SPC outlook does have the much of the CWA still under a Slight Risk w/ wind as the main threat. While large hail could be possible, the drier lower levels could melt any hail before it hits the ground. We are looking for up to 65 mph gusts with these storms. For Saturday, high pressure pushing into the region from the north will provide the CWA with a dry and slightly cooler day initially. The front that was the focus for convection today moves south of the area near the KS/OK border. Another shortwave will pass through the upper ridge interacting with the front by the late afternoon into the evening. The focus for any decent storm coverage will occur along and north of the front to impact our area, basically south of Highway 40. SPC has a Marginal threat for severe in this region, with some guidance showing a bit further push northward through the day, depending on where the actual shortwave sets up. Looking for chance north of I-70 at 15-30% should enough instability push north. The main focus will be south, peaking in the 40-50% range over Greeley/Wichita counties. CAMs continue scattered precip into the 12z Sunday timeframe before ending east. Going into Sunday, the front to the south will lift north as a warm front into the western CWA. This combined with another shortwave, will trigger another round of convection, initially in the west near the front(20-30%), overspreading the area during the evening(20-40%) and eventually moving east by 12z Monday. The western CWA is under a Marginal Risk for severe storms by the afternoon in/near the warm front. With this front, a return to a southeasterly moist flow will ensue, with PW values reaching into the 1.4-1.8" range, especially in KS/NE. Model sounding show decent rainfall potential with very moist soundings, suggesting a decent rain threat as the activity moves east in the evening, but hail/wind threats possible in isolated cells. For temps, daytime highs this weekend will range in the 80s. Overnight lows tonight will range widely from the upper 50s west into the upper 60s east. Weekend lows will range in the upper 50s to lower 60s Saturday night, with mid to upper 60s expected for Sunday night. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 145 PM MDT Fri Jun 28 2024 Both the latest runs of the GFS and ECMWF continue to upper level ridging at 500mb stretched across the southern portion of the country, amplifying some by the end of next week. This will allow for W/NW flow aloft giving way to SW flow aloft late in the period. The passage of several shortwaves along the northern periphery of the ridge will interact with a surface low and associated front that will meander through the CWA and eventually settling south of the CWA. Both sets of guidance are showing a bit different set of areal coverage for rw/trw, but the overall consensus will be the chance(20- 40%) for late afternoon precipitation, as the evening hours will promote higher chances(40-60%) for storms. As with the past several days, the above normal temps as fueled dry conditions during the daytime hours, allowing for sunset/evening convection chances. Can`t rule out some strong to severe cells to impacts areas, along with some localized heavy rainfall with PW values 1-1.5" early in the week, with a 1-1.2" range for the latter portion. For temps, highs on Monday will range in the upper 90s over northeast Colorado into the low 100s for locales east of the Colorado border. For next Tuesday onward, mainly 90s expected each day, with areas along/west of Highway 27 seeing some mid and upper 80s mix in, especially for northeast Colorado. With Monday having much of the region seeing at least 100 degrees, some high heat indices are possible. With the area being dry for most of the daytime hours, low RH will be present. Areas along/east of Highway 83, especially Graham and Norton counties could have enough moisture present to give some readings in the 100-103 range. West of this, readings will be at/below forecasted highs. Conditions will be monitored for a potential Heat Advisory issuance if warranted. Overnight lows will mainly range in the 60s for most of the periods, but Monday night could have 70s present for areas along/east of Highway 83. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 535 PM MDT Fri Jun 28 2024 VFR conditions will prevail through the TAF period. While an isolated thunderstorm cannot be ruled out invof either terminal late this aft-eve.. confidence in storm development, location and coverage is low enough to preclude explicit mention. Light and variable winds will prevail this evening and overnight. Around or shortly after sunrise, winds will abruptly shift to the N-NNE and increase to 15-25 knots (GLD) or 12-17 knots (MCK). Northerly winds will veer toward the northeast and decrease to 7-12 knots by early afternoon.. remaining light and further veering to the east by the end of the TAF period. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ UPDATE...Vincent SHORT TERM...JN LONG TERM...JN AVIATION...Vincent