Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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964 FXUS63 KGLD 302315 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 515 PM MDT Tue Apr 30 2024 .KEY MESSAGES... - A marginal to enhanced risk for severe thunderstorms continues for the region Wednesday afternoon and evening. Isolated storms possible in the afternoon east of Highway 83 in northwest Kansas where large hail, damaging winds and perhaps an isolated tornado will be possible. Storms will become more widespread Wednesday night with large hail and locally heavy rainfall becoming the primary hazards. - Severe storms possible next Monday in eastern portions of the area. - Elevated to near critical fire weather possible Monday and Tuesday of next week. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 200 PM MDT Tue Apr 30 2024 Cold front has moved out of the area this afternoon with gusty northwest winds in its wake. Those winds will gradually diminish through the late afternoon and early evening. Tonight, a weak wave embedded in the southwest flow aloft combined with low level upslope at the surface might result in a few isolated showers, mainly overnight, from northeast Colorado into southwest Nebraska. However, confidence is low and most models are dry. Low temperatures will be in the 40s. Clouds will increase Wednesday morning with moisture return from the southeast. By 18z expecting most if not the entire area to be socked in with low to mid level clouds with east to southeast winds. Weak impulse in the southwest flow aloft comes across in the afternoon with warm front likely south of the area. With persistent easterly winds north of the warm front, clouds may persist well into the afternoon. This will impact not only thunderstorm chances, but temperatures. Convective allowing models not in the best agreement on where storms will initiate. The HRRR has a couple of isolated supercells initiating after 21z near southeast corner of the area moving northeast, and additional develop towards 00z in northwest corner of the area near the secondary cold front. NAMnest on the other hand keeps the area in the cool, cloudy and capped all day with more of a stratiform light drizzle or light showers. The NAM does show plentiful elevated instability and shear, but never taps into it. The NAM keeps surface temperatures in the upper 40s to lower 50s all day in most of northwest Kansas and southwest Nebraska, a solution that cannot be completely discounted. Given all the uncertainties, confidence in severe risk and temperatures is low. Wednesday night, upper heights continue to fall/cool with approach of main upper trough. Surface cold front will continue to plow southeast and should be through the forecast area by 06z. There will be a risk of severe storms during the evening with the stronger forcing. NAM finally shows elevated convection developing late in the evening which taps into MUCAPE in excess of 1000 j/kg and up to 3000 j/kg in eastern areas with deep layer shear of around 50 kts. The HRRR shows a similar environment during that time with elevated storms and a favorable combination of MUCAPE/shear that would suggest a risk for large hail. HREF shows lows probabilities of 6-hour rainfall amounts of greater than 1 inch at 06z across mainly southwest Nebraska, which is consistent with the HRRR which shows 1-2 inch amounts along the Kansas/Nebraska border area and the NAM which shows a bullseye of around 1 inch in the same general area. Storms will be moving at a fairly decent clip of 10-20 kts, so appears to be more of a heavy rain threat than flash flood threat. Storms continue to move east overnight, with perhaps a lingering risk for severe hail between 06-09z east of Highway 25, before moving out after 09z. Low temperatures will be in the 40s. After morning clouds, Thursday will be mostly sunny with highs in the 60s. Widely scattered light showers will be possible Thursday evening in western areas with a weak wave coming across in the zonal flow aloft. However, with no instability to work with and little moisture, impacts will be minimal. Lows Thursday night will range from the upper 30s to lower 40s. Zonal flow continues on Friday with another open wave coming out of Colorado in the afternoon. Convection should initiate on the higher terrain to the west with forecast SBCAPE values of less than 500 j/kg. Showers and isolated storms continue east into Friday night, possibly merging into a large area of light to occasionally moderate rain. GFS and ECMWF show 12-hour precipitation amounts by 12z Saturday morning of between a quarter and a half inch. High temperatures will be in the lower 70s and low temperatures will range from the low to mid 30s in northeast Colorado to the lower 40s in north central Kansas. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Issued at 200 PM MDT Tue Apr 30 2024 Saturday will be dry with shortwave ridging in the southwest flow. High temperatures will be in the upper 60s. Models are mixed regarding precipitation chances on Sunday. Next disturbance in the southwest flow passes well to the south in the GFS solution, but the ECMWF has a weaker, broader wave with a few showers/isolated storms further north. Confidence is rather low, but blended model did put in some 20 to 30 pops for the area during the afternoon and evening. Instability continues to be weak, so severe storms not expected. Temperatures warm into the 70s to lower 80s with lows Sunday night in the upper 40s to middle 50s. On Monday, the main trough ejects across the Rockies and a deep closed low will develop over the northern Rockies/adjacent plains by Monday afternoon. Most of the local area appears to get dry slotted on that track with a fire weather risk should stronger winds develop. Dry line trailing south across the High Plains may reside in eastern portions of the area Monday afternoon. Models show moderate instability along and east of the dry line with deep layer shear of 50-70 kts, parameters sufficient for a risk of severe storms including supercells. Uncertainty at that time range on location of the dry line is high and will likely fluctuate until the models can settle on a solution. High temperatures will be mainly in the 70s and lows in the 40s. Should be on the dry and breezy side of that system for Tuesday with highs in the 70s and lows in the 40s. May see another day of fire weather concerns with afternoon humidity minimums approaching 15-20% along with the breezier conditions. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 515 PM MDT Tue Apr 30 2024 KGLD...VFR conditions are expected through at least 14z. A northerly wind around 10kts at taf issuance will veer to the east overnight with speeds generally below 11kts. On Wednesday, east-southeast winds slowly increase through the day, gusting up to 25kts or so. Sub VFR cigs in stratus are possible in the 16z-20z timeframe and if the NAM model is correct, linger through the rest of the taf period. HRRR/GFS boundary layer relative humidity show the stratus (marking the location of a dry line) lifting to the northeast so at this time the late afternoon forecast of cigs is uncertain. Presently, am not expecting any precipitation through the period. KMCK...VFR conditions are expected through about 20z. A northwest wind gusting up to 25kts at taf issuance will subside below 10kts by 02z with winds veering to the east at speeds under 10kts overnight. On Wednesday, easterly winds gusting up to 25kts are expected. From 20z-24z, sub VFR cigs are expected in stratus. Will need to watch for a few showers in the vicinity of the terminal in the 08z-12z timeframe and again after 18z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...024 LONG TERM...024 AVIATION...99