Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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480 FXUS63 KGLD 081124 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 524 AM MDT Sat Jun 8 2024 .KEY MESSAGES... - There is a 60% chance for a significant, widespread severe event across the area this afternoon and evening. Very strong winds, large to very large hail, flooding, and maybe a tornado or two are all possible. The favored area is generally along and south of I-70 and Eastern Colorado. The entire area has a chance. - Active weather pattern continues Sunday through Tuesday with similar trend of storms moving in from the west during the afternoon/evening. - Potential break in the active weather pattern mid week with near triple digit temperatures. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 313 AM MDT Sat Jun 8 2024 Potential for a significant severe weather event this afternoon and evening. Current observations show showers and a few storms moving through NW Kansas as moisture availability has remained high and MUCAPE has remained around 500-2000 J/KG. Thankfully, storms should remains sub- severe with a lack of shear which has kept the storms pulsey in nature. For the daytime hours, today is forecast to be cooler with some cold air advection and some higher pressure trying to move in from the north. The presence of cloud cover during the day will also help with areas under cloud cover forecast to stay in the 70`s while the rest of the area that sees more sunshine is forecast to warm into the 80`s. Winds are forecast to out of the east (increasing moisture advection) with higher pressure to the north east and low pressure to the southwest. For this afternoon and evening, the severe chances have increased quite a bit given the moisture availability over the area, and the potential for the low pressure system to remain nearby. The features themselves are not forecast to generate storms over the area, but any outflows from earlier storms may be able to pop up a few isolated storms in the area (20% chance). The bigger problems is the storms that will likely form along the higher terrain in Eastern Colorado and move east into the area. These storms are forecast to move into an environment with good instability (1500-3000 J/KG of ML/MUCAPE), PWATS in excess of 1 inch, effective shear above 50 kts, and corfidi downshear vectors of 50-70 kts. This environment would be supportive of clusters to lines of storms moving across the area that produce heavy rain and very strong wind gusts. Given the strong downshear vectors, suggested linear mode, and flow within the cloud layer to 70kts, wind gusts up to 90 mph are possible. Most gusts will likely be in the 60-80 mph range, but higher values will be possible. For the hail, any initial storm and any embedded supercell will have the possibility of producing hail in excess of two inches. While some analogs suggest hail up to 4 inches, I went with up to 3 inches given that the effective shear may be too strong (60+ kts) to develop a good hail core. Storms may also quickly become clusters/linear which would lower the chance for larger hail. So most hail will likely be in the one to two inch range with isolated instances of large hail (similar to yesterday). Another issue with hail, especially with embedded supercells, is that accumulating hail would be possible with right move motion forecast to be much slower in the 10-20kt range. Any embedded supercell would also increase the flooding threat as the high PWATs and potential for more skinny CAPE at times suggest that these storms could be efficient rain makers. Some guidance is trying to give up to 3-4 inches for areas that have a supercell or slower cluster of storms. The flooding threat as a whole remains on the low to moderate side as without embedded supercells, the line would likely move to quickly for anything other than maybe some urban flooding prone areas to be affected. Finally, a tornado or two is possible, but the chances are generally low as the low level flow and shear are forecast to be relatively weak. Even if a QLCS/line of storms develops, the shear magnitude is forecast to be 10 kts or less which isn`t very favorable short of a spin-up or two. In regards to timing and coverage, the storms look to initiate out of the area by noon, but not move into the area until around 2pm-3pm MT. Storms would then move through the area from west to east until ~11pm MT / 12am CT. The main batch could be out of the area by 9pm- 10pm CT if the storms stay more as lines and just sweep through the area. For coverage, the entire has a chance, but south of I-70 is favored. If the higher pressure and the low pressure both push further south as guidance has been suggesting, the tracks and lines of storms would also be pushed south. All of Eastern Colorado may see storms irregardless of how the pressure pushes due to the terrain aided storm development, but would struggle to make it into KS/NE if the high pressure pushes in during the afternoon hours. As for confidence, confidence in storms occurring within the area is 90%, and 60% for a significant and widespread severe event. For tonight, the main line is forecast to push off before midnight. However, additional storms could develop if the low pressure nose remains too far north and keeps some surface convergence behind the main line along with outflows. Some shortwave energy may also move through and help a few storms form. As long as the storms earlier sweep through and don`t fall apart, most of the environment should be worked over and maybe up to 1000 MUCAPE may remain and give a small hail threat. But cloud cover and storm could linger through much of the night, keeping lows a bit higher in the upper 50`s and 60`s. Tomorrow, the ridge is forecast to begin amplifying which will weaken our flow aloft will high pressure remains near the surface. This would allow cloud cover to clear slowly through the day and keep temperatures mainly in the 70`s. Will need to watch for some afternoon/evening thunderstorms moving into Eastern Colorado with lower pressure trying to build back up along the Front Range and moisture availability remaining high. As of right now, no threats are expected, but could maybe see a marginal risk for severe weather in the far western portions of the area. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 232 AM MDT Sat Jun 8 2024 At the start of the long term period, looking at another shortwave moving through the flow, which continues the stormy pattern for the region; however, currently not anticipating severe weather for the CWA. Going into Tuesday morning, upper low pressure will move through the OK/TX Panhandle region, followed by high pressure building in over the Four Corners region through mid-week all the while low pressure meanders off the West Coast. It`s during the latter part of the work week this upper low begins its inland progression, breaking down the ridge, and allowing a return of more active weather to the area. Details at this range are uncertain, so continue to monitor the forecast. Cloud cover and showers/storms on Monday will keep temperatures below normal for this time of year - currently forecast in the 70s to low 80s. Tuesday will begin a warming trend with highs forecast in the low to mid 80s. Overnight lows Monday-Tuesday will be in the middle 50s to low 60s. With ridging really getting underway mid- week, will be looking at afternoon highs in the 90s and overnight lows in the upper 50s to middle 60s. Regarding shower/storm chances for the period, Monday`s chances will linger into Tuesday morning- afternoon before a drying trend thereafter - at least until Thursday evening-night when we`ll see daily chances return through the remainder of the long term period as the next system nears and subsequently moves through the area. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 518 AM MDT Sat Jun 8 2024 For KGLD... VFR conditions are forecast for the period, but do need to watch for sunrise low ceilings or fog this morning. Otherwise, the main hazard will be clusters of storms or a line of storms that is forecast to move through somewhere around 00Z. These storms could produce significant severe weather with winds in excess of 75 mph and hail above 2 inches. They could also miss the terminal with some rain and gusts to around 40 kts. After that, will need to watch for where a line of storms behind the main line sets up, but no other hazards currently forecast. For KMCK... IFR conditions are possible this morning with fog and/or low stratus clouds. The showers and storms earlier in the night appear to have lowered the chances for fog and stratus along with winds having a more northwesterly component the last hour or two. However, nearby sites to the northeast are reporting worsening conditions, so have left it in the TAF for now. Otherwise, the main hazard will be a line of storms moving through just after 00Z. These storms could produce significant severe weather including winds above 75 mph and hail above 2 inches. But the chance at KMCK is lower compared to the rest of the area with chances for storms around 60% instead of 80%. After that, will need to watch for some showers or an isolated storm, but no other hazards are currently forecast for the rest of the night. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...KAK LONG TERM...CC AVIATION...KAK