Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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418 FXUS63 KGLD 031944 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 144 PM MDT Fri May 3 2024 .KEY MESSAGES... - Thunderstorms will develop along a cold front surging southeastward through the area late this afternoon and evening. Damaging winds and instances of large hail appear to be the primary hazards. Isolated supercells capable of producing all hazards may develop in advance of the front, south of Highway 40 in CO/KS, between 4-8 pm MDT. - Fire weather concerns return Monday through Thursday for most of the Tri-State area, but favor along and south of I-70. - Thunderstorms, a few of which may become strong to possibly severe, will be possible Monday afternoon/evening. && .SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 130 PM MDT Fri May 3 2024 Not much has changed from previous thinking with two areas of concern for the remainder of the afternoon and this evening. Convective initiation has occurred in eastern Colorado near Las Animas. HRRR shows this activity expanding into northeast Colorado south of I-70 and northwest Kansas over the next few hours. Latest analysis and forecast of SBCAPE shows 1500-2000 j/kg available along with effective bulk shear values of 40-50 kts. Those parameters should be sufficient for a few severe thunderstorms capable of producing large hail, damaging winds and perhaps a tornado with any discrete supercell. Further north, initiation has also occurred along the cold front in the Nebraska panhandle. As the cold front surges south this evening, convection will increase rapidly into a line capable of producing damaging wind gusts. Given the same parameters above, a few embedded cells in the line will also be capable of producing large hail and a brief tornado. The front will exit the area by around 06z ending the severe threat, though a few showers and storms may linger past 06z in southern and eastern areas. Mean precipitation amounts for the event range from around a tenth to a quarter of an inch in Colorado, a quarter to a half inch west of Highway 83, and around a half inch east of Highway 83. The higher percentiles show locally up to 1 inch possible in just about the entire area, with up to about 1.5 inches in northeast corner (McCook, Oberlin, Norton) and southern areas (Tribune, Leoti). Winds will gradually diminish overnight with low temperatures ranging from the lower 30s in Colorado to the lower 40s in north central Kansas. Saturday will be mostly sunny and breezy with just a hint of shortwave ridging aloft ahead of weak shortwave in southeast Colorado. High temperatures will be in the lower 60s. Saturday night now looks dry with the shortwave staying south of the area. There will be some increase in clouds with low temperatures in the lower 40s. Models do hint at fog developing in western portions of the area late Saturday night into Sunday morning (along the Kansas and Colorado border area and westward). Southwest flow aloft continues on Sunday with embedded weak waves which may result in a few isolated showers and thunderstorms by Sunday afternoon. There is a very narrow corridor of weak instability forecast along the Kansas and Colorado border area with a 100-200 j/kg currently indicated. So, not expecting any severe storms should any develop. High temperatures will be in the upper 60s to lower 70s. Shower and thunderstorm chances increase going into Sunday night with height falls ahead of the approaching trough and nocturnal low level jet. MUCAPE increases overnight to 1500-2000 j/kg with shear values of 40-50kts. So may see elevated thunderstorms late with a risk for hail, but confidence is low at this time range. Low temperatures will be in the 50s. Main trough axis ejects out of the Rockies and across the plains with a negative tilt on Monday. Surface low will deepen in the Nebraska panhandle with the dry line trailing south into the forecast area. The dry line will be the focus for convective initiation in the afternoon and the models indicating the dry line will likely be in eastern areas at least for a few hours before moving east. Timing of initiation will be critical, but if it happens before the dry line moves out may see a short window for severe storms along/east of Highway 83. Instability and shear will be more than adequate for a risk of large hail, damaging winds and tornadoes. West of the dry line may see few wraparound high based showers, but no severe threat. However, afternoon relative humidity values will be dropping to near critical or critical values and wind speeds also appear to meet critical thresholds for fire weather concerns. Precipitation should be east of the area Monday night. High temperatures will range from the upper 60s in Colorado to the upper 70s in north central Kansas and lows Monday night in the upper 30s to lower 40s. && .LONG TERM /TUESDAY THROUGH THURSDAY/... Issued at 243 AM MDT Fri May 3 2024 For the long term period, active weather is possible Monday with generally average temperatures and daily precipitation chances through the week. Sunday is forecast to have an upper low/trough push into the Western CONUS and move towards the Four Corners region. Meanwhile, moisture is forecast to stream in from the south near the surface as a surface low develops along the Front Range while additional moisture moves in over the mountains. This could lead to a fairly cloudy day where temperatures will cap in the 60`s, though any area with sun for a couple of hours should reach the 70`s, especially near and west of the Colorado border. Showers and a few storms could develop with all the moisture in the area, but the severe threat should be near zero with instability still forecast to be fairly low with MUCAPE generally near or less than 500 J/KG. Sunday night through Monday is when conditions are forecast to get more interesting as the upper low moves near and over the area along with the surface low. One the first things to watch will be the winds. With the speed of the upper trough and how deep it could get, the pressure gradient and height gradients could get fairly strong and allow winds to exceed 30 mph and gusts exceed 55 mph starting as soon as Sunday evening. However, confidence is currently only around 40% as ensembles show a fairly high spread in 500mb tracks and progression. This in turn also affects the surface low and it`s progression. One of the main things that could keep the winds on the lower side is that some of the ensembles are pulling the trough north. This would shift the stronger gradients more towards Nebraska and the Dakotas. Our winds would still strengthen above 20 mph with gusts above 35 mph, but high wind criteria warnings would become unlikely. The chances for the high winds then increase the further south the track of the main surface low goes (farthest south looks to be around the Southern KS border). In either scenario, low temperatures Sunday night will likely stay in the 50`s with the moisture, cloud cover, and increased winds over the area. For Monday, conditions are fairly variable given the surface low has solutions with tracks that go through the area during the day or hug the KS/CO border along with tracks that are north of the area and south of the area (I am referring to the deepest part of the surface low). In scenarios where the low moves through the area and is to the east during the day, moisture would lower across the area, increasing critical fire weather chances and lowering storm and severe storm potential. In solutions where the low and front stay over or near the area, critical fire weather conditions become less likely while storm and severe storm chances increase. Winds approaching high wind warning criteria become more likely as well. Would could be of particular concern is if the low is south of the area and the warm front is draped across the area. We then begin to face scenarios similar to recent events with a warm front and a dryline/cold front acting as storm genesis points. High temperatures are forecast to be in the 60`s behind the system and in the 70`s and maybe low 80`s ahead of the system. Monday night remains just as varied with conditions ranging from calming and dry, to stormy with high winds. Currently, don`t have a good inclination towards any one scenario so have gone with a more neutral forecast and am waiting for better consensus in guidance and maybe better sampling of the system (since it is still offshore). Tuesday and Wednesday look to be more "average day" with near average temperatures in the 60`s and 70`s and some small chances for precipitation as the upper pattern is forecast to turn more to a broad trough with the initial disturbance pushing east while the trough as a whole spins over the Northern Plains. Will need to watch for critical conditions south of I-70 with the drier air over the area dropping RH into the teens. For the end of the work week, currently forecasting near average conditions in a broad trough pattern. Guidance is split on whether the upper trough just pushes off to the east or if a small low splits off and retrogrades west. In either case, there is the possibility of another front if the trough is strong enough as it pushes off to the east, though there may not be much moisture available for storms to work with. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1118 AM MDT Fri May 3 2024 VFR expected to prevail at both KGLD and KMCK through this afternoon. Isolated storms may develop in northwest Kansas late this afternoon, but probability of directly impacting the terminal is low. Tonight, a strong cold front will move through both terminals between 02-04z. The front will be accompanied by thunderstorms and strong surface winds shifting to the north. Some visibility restrictions due to blowing dust will be possible along and immediately behind the front. Storms will continue south during the late evening with surface winds gradually diminishing through the overnight. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...024 LONG TERM...KAK AVIATION...024