Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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532 FXUS63 KGLD 021655 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 1055 AM MDT Tue Jul 2 2024 .KEY MESSAGES... - Chance for storms today, mainly along and south of Highway 40. There could be a severe storm or two with wind gusts up to 70 mph. - Wednesday, there is the potential for a significant severe weather day for the area. Storms are forecast to move west to east across the area with the potential to produce hail up to 3 inches, wind gusts up to 75 mph, and a tornado or two. There are a few scenarios where storm coverage is instead limited and weak. - Breezy to gusty 4th of July; albeit a bit cooler. && .SHORT TERM /THROUGH WEDNESDAY NIGHT/... Issued at 218 AM MDT Tue Jul 2 2024 Current observations show a few showers in Eastern and Western portions of the area while an upper trough and low continue to shift east over the area. Dense fog has also been reported over McCook with nearby counties seeing slight reductions in visibility. This patchy fog will likely affect most counties along and north of I-70 with the calm winds and moist air in place. If it weren`t for the cloud cover, most of the area might already be in dense fog. With the clouds forecast to linger, fog will remain somewhat limited with dense fog being patchy. Fog should clear a few hours after sunrise with increasing temperatures. For the remainder of today, cloud cover is forecast to slowly burn off for Eastern portions of the area with partly cloudy skies over the rest of the area. With the cloud cover and upper trough axis swinging through the area, cooler temperatures in the 80`s are forecast. A few storms are possible this afternoon, but would mainly favor Eastern Colorado and south of Highway 40. The front is forecast to be well south of the area which will be the focus for most of the storms today. However, some storms are forecast to move in from the higher terrain in Colorado, especially if the lower pressure lingers in East-Central Colorado. This would provide the area`s primary chance for severe storms with wind gusts up to 70 mph possible. There is a 15% chance for storms across the rest of the area north of Highway 40 with high moisture availability, but the lack of forcing that is forecast would likely keep the rest of the area clear. For tonight, most of the area should see partly cloudy skies with light winds. Along and south of Highway 40 may continue to see storms develop in similar fashion to the past few nights. As such, the severe threat should be near zero by midnight. Lows are forecast to be in the upper 50`s to 60`s. Fog will be possible again, especially east of Highway 25 with light easterly winds and relatively moist low level air. Tomorrow, a more active day is forecast as another trough axis swings through the Rockies and Northern Plains. Temperatures may be a few degrees cooler than the prior day with the continued troughing aloft and possible cloud cover through the day. As the next trough advances, low pressure is forecast to develop in Eastern Colorado. With moisture availability forecast to remain fairly high, storms are forecast to develop in Eastern Colorado and push east across the area. In most forecast soundings, CAPE is forecast to be above 2000 J/KG, mid level lapse rates around 8 C/KM, and effective shear around 45-55 kts. These conditions would favor very large hail with initial storms or supercells with analogs suggesting hail to 3 inches. However, the strong winds higher up, increasing downshear vectors, and increasing shear would likely favor storms clustering or becoming linear and moving across the area. With downshear vectors forecast to reach 55-65 kts and similar winds in the higher levels of the clouds, winds up to 75 mph are possible. Even that may be a little underdone and will need to be watched. As for tornadoes, low level shear and SRH isn`t forecast to be that high, but with the overall shear in the environment being high and the potential for both supercells and a line of storms, a tornado or two is possible. Storms could start as early as 19Z (1pm MT), but the more likely time period is around 21Z through about 3Z (3pm-9pm MT). There is some suggestions (namely the Nam 3k and some GEFS ensemble members) that storms will struggle to maintain themselves as they move east. This looks to be more likely in scenarios where convection is ongoing during the day and/or increased cloud cover from prior storms limits the instability in the environment. In this case, storm and severe chances would lower quite a bit east of Eastern Colorado. Tomorrow night is forecast to be similar to previous nights, where temperatures largely remain in the 60`s and storm chances / increased cloud cover remain present over the area due to the high moisture availability. && .LONG TERM /THURSDAY THROUGH MONDAY/... Issued at 100 AM MDT Tue Jul 2 2024 Thursday...an upper level low pressure area is forecast to move east-southeast across the northern plains with the flow aloft from the west-northwest. Guidance continues to advertise a generally dry day with a 20%-30% chance for thunderstorms during the night across the southwest 1/2 of the forecast area as a weather system per 700- 500mb relative humidity moves through from the northwest. Otherwise, we`re looking for breezy north winds during the day as surface high pressure strengthens from the north. High temperatures are forecast to be below normal in the upper 70s to middle 80s, spot on with 850mb temperature bias` over the past week or so. Low temperatures fall into the lower to upper 50s. Friday...the forecast area is forecast to be under northwest flow aloft, in between low pressure to our north and east and a strengthening ridge to our west. Similar to Thursday, it appears per GFS/ECMWF/GEM 700-500mb relative humidity forecasts that another weather system skirts the far southwest 1/3-1/4 of the forecast area during the afternoon and early evening hours, potentially supporting a 20% chance of thunderstorms. Presently, pops are limited to the Flagler area. High temperatures are forecast to remain below normal in the lower to middle 80s, in great agreement with GFS/ECMWF/GEM 850mb temperature bias` from the past week or so. Low temperatures are forecast to be in the middle 50s to lower 60s. Saturday...not much change in the general 500mb pattern when compared to Friday. There is some agreement from the GFS/ECMWF/GEM models that another weather system will move through the area during the afternoon through late evening/overnight hours, supporting 20%- 30% chances for showers and thunderstorms. GFS/ECMWF/GEM 850mb temperatures rise a few degrees, supporting high temperatures in the upper 80s to lower 90s. Low temperatures are forecast to be in the middle 50s to lower 60s. Sunday...500mb pattern remains similar to Friday and Saturday. GFS/GEM models are in fair agreement bringing another weather system into western parts of far eastern Colorado during the afternoon, supporting a 20% chance for thunderstorms. This system continues moving southeast through the remainder of the forecast area overnight with 20%-30% chances for thunderstorms. High temperatures are currently forecast to be in the 85-90 degree range. This could be a bit warm given GFS/ECMWF/GEM 850mb temperatures supporting highs about 5F to 7F cooler. Low temperatures fall into the middle 50s to lower 60s. Monday...the 500mb pattern shows no signs of significant change when compared to the prior few days. That is also reflected in the thunderstorm forecast with 20% chances during the typical afternoon and overnight hours. High temperatures look to be near normal in the middle 80s to lower 90s with low temperatures in the upper 50s to lower 60s. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1051 AM MDT Tue Jul 2 2024 Instances of MVFR ceilings continues for KMCK as another batch of 850mb moisture looks to move across SW Nebraska but will end during the early afternoon hours. Watching for some strong to perhaps severe storm potential near the KGLD terminal this evening; some AMD may be needed if confidence increases enough that the terminal will be impacted. Increasing moisture again overnight will lead to stratus and fog potential at each terminal with KMCK currently favored for fog due to lighter winds. Showers and storms will also redevelop tonight with VCTS at this time favored for KGLD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...KAK LONG TERM...99 AVIATION...Trigg