Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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188 FXUS63 KGLD 260839 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 239 AM MDT Wed Jun 26 2024 .KEY MESSAGES... - Not as hot today; thunderstorms develop across east Colorado late afternoon/early evening before spreading into Nebraska and Kansas. Severe possible along with torrential rainfall. - Scattered severe storms again Thursday with large hail, damaging winds, torrential rainfall and perhaps a window of opportunity around sunset for a tornado. - Near daily chances for thunderstorms Friday into next week. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 225 AM MDT Wed Jun 26 2024 A moist airmass is starting to advect into the area from the northeast where dew points have been increasing 5-10 degrees with the passage of the incoming boundary. Weak isentropic lift and interaction with the moist boundary is leading to some scattered showers across northern Kit Carson county as of 08Z; RAP suggests that this corridor may continue to move south through sunrise so have introduced slight chance pops (15%) to account for this. )Surface high continues to reside across the SW CONUS, but is forecasted to flatten out through the day today. As a result, a reprieve from the triple digit heat looks to be in store for the area with highs in the low to mid 90s. Main focus for the day will be thunderstorm development across eastern Colorado. Discrete strong to severe storms look to develop during the late afternoon hours and into the evening as a shortwave emanates off of the Rockies; some supercellular characteristics may be possible as well with shear around 40 knots and 3000 j/kg of MUCAPE. Large hail looks to be the primary hazards initially across Yuma, Kit Carson and Cheyenne (CO); will need to watch for flooding potential as well especially with any right moving storms as the motion is around 5 knots and PWATS increasing up to around 2 inches. The storms are then forecasted to grow upscale into a cluster with perhaps a damaging wind potential as they move across the state line especially with cold pool driven enhancements. Some localized flooding potential may occur as well with the high PWATS but currently think that storms will be moving quickly enough to avoid any further hydro issues. The difficult portion of today`s forecast will be how much the surface high across the south breaks down. If some amplification remains then the rainfall will shift to the north or be delayed until the subsidence exits the area such as the ECMWF. Other guidance such as the RAP/NAM differ on the area with the greatest moisture with the RAP favoring north of I70 and the NAM to the south. All this said, continues to keep me from increasing pops to much and does bring some cautiousness. Overall though this does appear to be the area`s relative best chance at meaningful precipitation that has been seen in a few weeks. Thursday, will see the moist air mass continue across the area. Will need to watch for stratus and perhaps fog across the area during the morning; fog will be dependent on how quickly the rainfall can exit and how much occurs. Fairly decent agreement with guidance with 850mb moisture greater than 90% hanging around the eastern portion of the area for the good part of the day in the form of stratus. With the stratus and dewpoints in the low 70s have lowered high temperatures for the day into the low to mid 80s across the east. Western portions of the area will see more breaks in sun where highs in the low to mid 90s remain forecasted. Another threat for severe storms exists on Thursday, but the coverage and hazards will be highly dependent on how the Wednesday system plays out. Large hail and damaging winds will be the primary threat; the large hail threat may be a bit more uncertain given meager lapse rates of 6.5 to 7.0 C. It appears that two zones for convective initation will be in play as a warm front and a dry line will be present across the area; will also need to watch for any additional lingering boundaries from the potential storm cluster from Wednesday night. A tornado threat may also develop along the warm front and across any additional outflow boundaries as forecast guidance is showing 0-3 SRH around 300 m2/s2 and 0-1 SRH around 150 m2/s2. NAM hodographs show decent low level shear as well; a dewpoint depression of around 10 degrees and 3000 j/kg of SBCAPE does indicate that any storm should be surface based. PWATS will continue to be very high as well around 2 inches still which will lead to continued concern for torrential rainfall and perhaps additional flooding concerns especially where heavy rainfall may fall Wednesday night. Friday, will see a similar pattern as another wave moves off of the Rockies bringing shower and storm potential to the area. Storms again look to initiate across eastern Colorado and move into the adjacent states; moisture and PWATS at this time don`t appear to be as high and there may be some capping concerns as well. A warm front does look to be draped across the area again as well but the exact location differs between models so is difficult to pinpoint down at this time. Highs are currently forecasted in the 90s across the area with the potential for upper 90s across the south. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Issued at 215 AM MDT Wed Jun 26 2024 For the weekend, will be on the northern periphery of a ridge centered over the southern plains. Perturbations rotating around it will approach from the southwest each afternoon and then move across the area during the night with a chance for showers and thunderstorms. At the surface, will see post frontal upslope winds on Saturday with temperatures closer to normal. Surface based instability will be just hugging the southern Kansas counties and nosing into northeast Colorado Saturday afternoon, which would be the only locations that could see a marginal severe risk due to deep layer shear around 45 kts. Surface instability goes to zero fairly early Saturday evening with only some lingering weak elevated instability through Saturday night with scattered showers and isolated storms. Low temperatures will be in the 60s. On Sunday, a narrow corridor of moderate instability develops along/just west of the Colorado and Kansas border by the afternoon with the moist return flow at the surface. Deep layer shear will be around 35 kts, and with the better instabilty expect to see a higher risk for severe storms, especially in Colorado and near the Colorado/Kansas border. Instability will weaken as storms move northeast Sunday evening with the severe risk declining, but if storms manage to cluster may see some locally heavy rainfall as indicated by the GFS across areas north of Interstate 70 and into southwest Nebraska. High temperatures will be in the upper 80s and lows in the upper 60s. For Monday and Tuesday, the ridge weakens as a shortwave trough moves from the northern Rockies into the northern plains. It will drive a front through the area sometime late on Monday. However, the area may get dry slotted ahead of the front with westerly winds. Moisture appears to be very limited and instability is weak. Models still showing scattered convection with some synoptic scale forcing on the southern fringe of the upper wave. Confidence is on the low side for any severe threat at this time other than gusty winds with deeply mixed inverted-v soundings. Temperatures ahead of the front will warm back into the lower 100s and lows Monday night ranging from the lower 60s in Colorado to the lower 70s in north central Kansas. Will be post frontal on Tuesday with moist low level return flow by Tuesday afternoon resulting in modest instability in southern areas, fairly weak elsewhere. Looking at convection developing from the southwest in the afternoon with shortwave rotating around the southern ridge and across the area Tuesday night. Some suggestion of locally heavy rainfall from the GFS across southern areas in the better instability, but confidence at this time range is low. High temperatures on Tuesday will be in the mid to upper 90s and lows Tuesday night in the 60s. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 1051 PM MDT Tue Jun 25 2024 For KGLD & KMCK... VFR conditions are forecast through the period. The main concern is the possibility of storms between 00-06Z as storms move across the area from west to east. There is a question of if they will survive and get to the terminals, but if they do they may be severe with hail and winds around 50kts. There is also a concern of low stratus, but looks to be more likely for after 06Z. && .HYDROLOGY... Issued at 225 AM MDT Wed Jun 26 2024 Any storms that develop across western portions of Kit Carson, Cheyenne (CO) and Yuma counties late this afternoon and evening will have the potential for torrential rainfall leading to some flooding. Precipitable water values look to increase to around 2 inches during this time frame along with right moving storm motion of 5-10 knots storms will not move very quickly and may produce localized areas of flooding. Due to the recent hot and dry weather and localized and conditional potential of this threat have opted to not issue any hydro highlights. Storms look to grow upscale after initial discrete cells but may have to overcome some dry lower level air across NW Kansas. Once the low levels can saturate then the continued potential for torrential rainfall will return along some isolated flooding potential in low lying areas. Scattered storms are again forecasted on Thursday with continued very high PWATS around 2 inches. There is potential for multiple rounds of rainfall Thursday afternoon and into the overnight hours. Those who see heavy rainfall Wednesday night will be most at prone for additional flooding. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...Trigg LONG TERM...024 AVIATION...KAK HYDROLOGY...Trigg