Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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227 FXUS63 KGLD 251645 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 1045 AM MDT Tue Jun 25 2024 .KEY MESSAGES... - Another hot day today with triple digit temperatures forecasted area wide; Heat Advisory Graham and Norton counties. - 30% chance of storms this afternoon mainly east of Highway 83; severe downbursts/microbursts the primary threats. - Slightly cooler Wednesday and Thursday with better potential for rainfall; severe weather also possible. && .SHORT TERM /THROUGH THURSDAY NIGHT/... Issued at 220 AM MDT Tue Jun 25 2024 Mainly zonal upper level flow is located across the area with a departing shortwave across Gove county leading to a few lingering showers and storms. The main story for the day continues to be the triple digit heat and heat indices. Have decided to leave the inherited Heat Advisory in place for Norton and Graham counties. A boundary looks to be in place across eastern portions of the area with drier air behind it; if this boundary does set up a bit further south/east then the 105 heat index criteria may not be met as dew points will be lower. Either way it will still be hot not only in the Heat Advisory area but across the entire forecast area with virtually the entire CWA forecasted to see triple digit heat. Along the same boundary will be monitoring for thunderstorm development mainly along east of a McCook to Leoti line. Similar to Monday, pulsey summer time thunderstorms look to be the main concern with severe downburst/microburst potential as inverted v soundings will again be present across the area. Some blowing dust may accompany the strongest downbursts and be localized in nature. The threat for any hail looks to be fairly low due to the weak flow resulting in weak shear across the area; also do have concerns for residence time aloft in any updraft as well for large hail to be a threat. Overall coverage is a bit tricky to forecast in weakly forced setups as CAMS normally are not very reliable; have opted to focus my highest pops along the above mentioned boundary and where there is a noticeable increase in 700-500mb moisture. Wednesday morning, fairly good consensus thus far with an increase in 850mb moisture advecting in from the NW over mainly Yuma, Kit Carson, Cheyenne and western portions of adjacent counties. Will need to watch for fog/stratus potential around sunrise Wednesday, have not introduced any fog wording into the forecast yet as I want to monitor for any potential changing of location, but did increase sky coverage to account for this. For the day Wednesday, a reprieve from the triple digit is currently forecasted for the area with highs in the 90s. The surface high that has been situated across the area leading to the hot temperatures of late looks to get shunted to the south as a potent trough from the Pacific Northwest influences the upper level pattern. This will then open the area to be impacted from shortwaves off of the Rockies; which is what the NAM, RAP and GFS all currently suggest. Very high PWATS ranging from 1.6 to 1.9 inches look to be in place across the area with easterly upslope flow in place as well. Forecast soundings across eastern Colorado do support some large hail potential as well initially before showers and storms grow upscale and move across the state line. A caveat however.... is the ECMWF which is slower with the NW trough shunting the surface high to the south out of the area. If the surface high remains then subsidence remains across the area virtually eliminating our precipitation chances. Since the ECMWF is currently the outlier, confidence is on the lower end of this occurring but does need to be mentioned and this is the reasoning for keeping pops around 50% and not increasing them. Thursday, may see some stratus linger about for the good majority of the day across the east so have stared trending high temperatures down across that portion of the area. If the stratus is thick enough and lingers all day (which the NAM suggests) it may be a struggle for some locales to reach the 80s. Similar to Wednesday, another wave moves off of the Rockies, this time the surface high will be shunted south of the area which will favor shower and storm potential across virtually the entire forecast area. At this time it appears that large hail will be the primary hazard initially before becoming a damaging wind/heavy rain threat as storms grow upscale. && .LONG TERM /FRIDAY THROUGH MONDAY/... Issued at 215 AM MDT Tue Jun 25 2024 Cold front will slip into the area Friday morning and stall out just south or possibly in the southern part of the forecast area by the time of peak heating and convective initiation Friday afternoon. A fairly decent shortwave will be coming out of Colorado to aid in ascent. While the front will undoubtedly be the favored area for convection, the post frontal upslope environment should also see fairly high precipitation chances going into Friday night. Instability is modest at best, generally 500-1000 j/kg, though deep layer shear is excellent due to the directional component. Forecast soundings show a hot, dry, deeply mixed environment, even post frontal, which should yield a low-end marginal risk for severe wind gusts or hail. High temperatures will be in the mid to upper 90s and lows in the 60s. Upper ridge strengthens over Texas for the weekend resulting in southwesterly flow aloft over the central High Plains. Will see weak perturbations rotate around the ridge resulting in scattered thunderstorm chances both days. Chances on Saturday may wait until Saturday night with fairly stable conditions during the day, but with more typical afternoon and evening chances on Sunday. In fact, models show a narrow corridor of moderate instability Sunday afternoon straddling the Kansas and Colorado border area along with deep layer shear of 40-50 kts. That would support a severe risk, including supercells, if the trend continues. High temperatures will be in the mid to upper 80s on Saturday and low 90s on Sunday, with lows in the 60s. Upper pattern will be more or less the same on Monday, but surface pattern shows more of a dry, southwest wind in most of the area with the instability axis shifting eastward from Hays into southwest Kansas. With another shortwave coming out of Colorado in the afternoon and evening, storms chances will continue. Would probably only see a marginal wind risk with storms in the majority of the area with temperatures back into the lower 100s and deeply mixed, inverted-v soundings, but closer to the aforementioned instability in eastern areas could see a hail threat with stronger storms. However, confidence in those kind of details are low at this time range. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1045 AM MDT Tue Jun 25 2024 KGLD...VFR conditions are expected through the period. A northerly wind gusting to 20kts at taf issuance will continue this afternoon, subsiding below 10kts while veering to the northeast overnight. Wednesday morning, east winds gusting up to 25kts are forecast. KMCK...VFR conditions are currently forecast through the period. A west wind up to 10kts at taf issuance will veer to the northwest this afternoon, increasing a bit with gusts to 20kts possible. Tonight, northerly winds around 10kts veer to the northeast. Wednesday morning, winds veer to the east at speeds around 12kts with a few higher gusts. Stratus and sub VFR cigs are possible a few hours either side of 15z Wednesday. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Heat Advisory until 8 PM CDT this evening for KSZ004-016. CO...None. NE...None. && $$ SHORT TERM...Trigg LONG TERM...024 AVIATION...99