Area Forecast Discussion
Issued by NWS Springfield, MO
Issued by NWS Springfield, MO
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433 FXUS63 KSGF 260102 AAA AFDSGF Area Forecast Discussion...UPDATED National Weather Service Springfield MO 802 PM CDT Sat May 25 2024 .KEY MESSAGES... - Slight (2 of 5) to Moderate (4 of 5) Risk for severe thunderstorms late tonight into Sunday morning (between 11 pm - 7 am). Damaging winds up to 80 mph and hail up to baseballs are the primary potential severe weather hazards. There is also a conditional risk for a few tornadoes. - Flood Watch in effect tonight for the entire area. Repeating thunderstorms could produce 1-3 inches of rainfall. - Slight (2 of 5) to Enhanced (3 of 5) Risk for severe thunderstorms on Sunday afternoon and evening. Primary hazards are damaging winds up to 70 mph and large hail up to golf balls. && .MESOSCALE... Issued at 800 PM CDT Sat May 25 2024 Severe thunderstorms are ongoing as planned across Kansas and Oklahoma with the most significant concentration south of Wichita into northern Oklahoma. These storms have already produced baseball size hail, damaging winds and at least one tornado. The 00z KSGF sounding data revealed a vastly different airmass than 12 hours ago with significant destabilization having occurred. Surface temps in the 80s and dewpoints in the upper 60s have returned to the area with ML CAPE values being measured at 2300j/kg with very little cap remaining (21j/kg CIN). MU CAPE values were an impressive 3900j/kg therefore the airmass is primed. 0-6km wind shear was 50kts however the low level shear was weak. This will change overnight as the llj increases. Mid level lapse rates were also steep with a max of 8.6C/km measured in between 700-500mb. Latest high res guidance continues to indicate that these supercell storms will continue moving east this evening towards southeast Kansas with additional storms developing further north in Kansas. A low level jet is currently in the process of increasing across Oklahoma and this will nose into Kansas as well. This will increase the low level helicity therefore the tornado threat may begin to increase across Kansas/Oklahoma over the next few hours. An additional cluster of storms also looks to form further north, across north central to northeast Kansas. As storms move into our southeast Kansas counties (generally after 11pm), storms may begin to congeal into a cluster(s) of storms (either line segments or supercells). These cluster(s) still look to produce large hail up to the size of baseballs, damaging winds of 60-80mph and even a strong tornado. These supercell storms then look to move into western Missouri however a few trends are noted in most recent high res models. One being that the storms that eventually form further north (between Wichita and Kansas City) may actually congeal into a strong enough cold pool to begin pushing southeast into the area after 2-3am. With a 50kt llj this could create a northwest to southeast oriented backbuilding line of storms. It is hard to pinpoint where this may occur but if it does then this would increase the flash flooding threat substantially. Last few HRRR runs show this with a few pockets of 3-5 inches of rainfall wherever storms move over the same areas. We will need to monitor this threat closely overnight. This back building line of storms would still pose a risk for large hail, damaging winds and tornadoes. This cluster or line of storms could persist through the 5-7am timeframe. Therefore a messy convective mode looks likely overnight and given the amount of people outdoors it will be imperative people have multiple ways of receiving warnings and having a way to get indoors. We are planning a special balloon launch in the 4-6z timeframe to get another look at the local atmosphere ahead of the storms. && .SHORT TERM /THROUGH MONDAY/... Issued at 255 PM CDT Sat May 25 2024 This Afternoon-Evening: A warm front is lifting north through the area this afternoon ahead of the next approaching shortwave trough. Ahead of this next system late tonight into Sunday, a rather dry and warm afternoon is unfolding. Highs will range from lower to middle 80s across the area, with dewpoints climbing into the middle to upper 60s, near 70 as the front warm front lifts into central Missouri. Expectations are for the area to remain capped through the afternoon and evening. This has been well captured by the guidance. Supercell thunderstorms will develop west of the area across the Southern/Central Plains, with a Moderate Risk (4 of 5) draped across this area. Tonight: By tonight, the atmosphere becomes primed for development of severe thunderstorms. A brief overview of the environment, depicts instability around 2000 to 4000 J/kg in the vicinity of 0-6 km deep layer shear of 35 to 40 knots. Both deep layer and low-level shear will be on the increase into tonight. Additionally, a low-level jet around 45 to 50 knots builds into the area tonight, which will further amplify low- level flow into the region. This will correspond to strong mid- level flow around 500 mb. SPC highlights a Moderate Risk (4 of 5) into southeast Kansas and southwest Missouri. Further east, Enhanced (3 of 5) to Slight (2 of 5) risk exists into Missouri. Ongoing supercell thunderstorms to the west will slowly slide into the area, generally after midnight for portions of far southeast Kansas and along the Missouri/Arkansas border. Supercell coverage may not be widespread, though the activity that is present will likely be intense. Initial thought is that activity will remain semi- discrete in nature for areas along and west of Interstate 49. Hazards in this area include destructive damaging wind gusts up to 80 mph, large hail up baseballs, and a strong tornado or two. The tornado environment is characterized by sufficient 0-1 km shear around 25 to 30 knots and SRH values around 250 to 300 m2/s2. With winds slightly backed out of southeast and low LCLs, mature supercells may be able to tap into a favorable low-level environment. However, a tornado outbreak is not expected at this time as the window for tornadic development in short-lived before the activity grows upscale. Additionally, steep mid-level lapse rates and ample instability through the hail growth zone supports large hail. Large Hail Parameter paints a picture of values greater 20. As thunderstorms push further east towards Highway 65 in the early morning hours, the transition from supercells into line segments is expected. The primary hazard will become damaging wind gusts up to 80 mph, with less focus on large hail. As for tornadoes, 0-3 km shear around 25 knots from the west- southwest, would support a few brief and weaker tornadoes where the segments are able to become balanced along the UDCZ and bowing structures exist. CAMs suggest this line of thunderstorms to persist into central and south central Missouri, towards sunrise Sunday morning. Damaging wind gusts of 60 to 70 mph will be the primary risk with a gradual "weakening" trend east of Highway 65, though some guidance suggests otherwise. This will need to be monitored closely with radar and mesoscale trends. There is an additional concern for localized heavy rainfall and flooding across the area. HREF highlights a few corridors, particularly across west central into central Missouri of 1 to 3 inches or more in short periods of time where thunderstorms train over the same areas. Pinning down these exact locations in subjective in nature, but the general consensus is that the conditions are favorable for heavy rainfall with efficient rainfall rates to produce flash flooding. Additionally, there may be some backbuilding in the vicinity of the warm front and nose of the low-level jet into this area. A Flood Watch has been issued for late tonight (1 AM Sunday) through Sunday evening (7 PM) to account for this increasing potential. Sunday: The overnight MCS complex will be ongoing Sunday morning across portions of central and south central MO. How the overnight MCS evolves through Sunday morning will play a key role in the potential for additional strong to severe thunderstorms Sunday afternoon and evening along the trailing cold front. If thunderstorms are able to redevelop, the atmosphere will be supportive of large hail up to golf balls and damaging wind gusts up to 70 mph. The area of greatest risk extends from central into south central Missouri where an Enhanced (3 of 5) Risk exists. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 255 PM CDT Sat May 25 2024 (From Previous AFD) Upper level wave will push through on Sunday night with a drier air mass moving into the area. This should clear the convection to the southeast of the area with temperatures dipping into the upper 50s to low 60s. An upper low in Canada will drop southeast into the Great Lakes region early in the week bringing more of a northwesterly flow aloft to the area. The best moisture axis should remain over the deep south into the southern plains with precipitation chances fairly low for the first half of the work week. An upper level ridge will begin to push into the area on Thursday with moisture beginning to increase over the western CWA by late in the week. Temperatures in the long term period look to remain seasonal for this time of year. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 609 PM CDT Sat May 25 2024 Confidence is high that thunderstorms, some severe, will move into the TAF sites closer to 06z. These storms may linger for several hours at SGF, perhaps into 12z. Damaging winds are likely if these storms move through the sites. Winds outside of storms will be out of the south to southeast with increasing gusts overnight. A brief period of MVFR ceilings may prevail in the morning with VFR then expected for the rest of Sunday. There is a 30 percent chance of thunderstorms in the afternoon at SGF and BBG however confidence is too low to include at this time. Winds will gradually turn southwesterly during the day with increasing gusts. Low level wind shear is likely overnight at the sites. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...Flood Watch from 1 AM CDT Sunday through Sunday evening for KSZ073-097-101. MO...Flood Watch from 1 AM CDT Sunday through Sunday evening for MOZ055>058-066>071-077>083-088>098-101>106. && $$ MESOSCALE...Burchfield SHORT TERM...Perez LONG TERM...Perez AVIATION...Burchfield