Area Forecast Discussion
Issued by NWS Springfield, MO
Issued by NWS Springfield, MO
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809 FXUS63 KSGF 070025 AFDSGF Area Forecast Discussion National Weather Service Springfield MO 725 PM CDT Mon May 6 2024 .KEY MESSAGES... - Severe thunderstorms are likely tonight with the highest risk areas along and west of Highway 65. Primary hazard is damaging wind gusts of 70 to 80 mph. Additional hazards include frequent lightning, a few short- lived tornadoes and half dollar sized hail. Severe storms will move into the area after 9pm and continue overnight. - Localized flooding is also a concern tonight across southeast Kansas and western Missouri where localized pockets of 1-2 inches of rain will occur. - Additional strong to severe thunderstorms on Wednesday. Exact hazards remains in question, but very large hail, damaging, and a conditional tornado threat are all in play. SPC has a hatched Enhanced Risk (3/5) for most of the area. && .MESOSCALE... Issued at 725 PM CDT Mon May 6 2024 Storms have developed across a front across central Kansas and Oklahoma this evening. This activity will continue to move east this evening into tonight as an upper level trough moves east into the plains. The high res models continue to be in good agreement that these storms developing into a line and move into the far western portions of the area by 11pm then moving east across the area through the overnight hours exiting the area to the east by early Tuesday. Damaging winds of 60 to 80 mph winds remain the main threat with these line of storms especially along and east of Highway 65. Low level shear will also support a brief tornado risk within the line of storms with any surges to the east/northeast. Locally heavy rainfall and localized flooding will also be possible with the best potential across far southern Missouri. A few of the stronger updrafts will be capable of hail up to the size of half dollars. Storms have developed across north central Kansas into Nebraska early this evening with another area of storms across central Oklahoma into south central Kansas. The activity across northern Kansas and Nebraska are forming into line segments and should continue to move off to the northeast. The storms across central Oklahoma into south central Kansas are currently supercells in nature, but a cold pool should develop with these storms as they move east which should allow these storms to form into a line. Once the storms across Oklahoma and southern Kansas form into a line they will move off the east/northeast at 30 to 40kts. An unstable air mass will be in place across the area with 1500 to 2200 J/kg of MLCAPE in place west of Highway 65, with values of 1200 to 1700 J/kg to the east overnight. Damaging straight line winds will occur with the line of segments with gusts up to 80mph possible with the bowing segments. The 00Z SGF sounding is showing down draft CAPES over 1000 J/kg which is also supports strong down drafts. Low level shear will also increase tonight. 0-3KM shear vectors are currently at 26kt across the area and should increase to around 40kt to the northeast across of the line of storms. This will support a QLCS tornado risk with the line of storms with surges in the line to the northeast. There are some indications that the the southern part of the line of storms will become outflow dominate across southern MO/northern Arkansas and the outflow become parallel with the 0-3km shear vectors and could lead to the potential for some training of storms and a localized flooding risk tonight. Will have to watch exactly where this will form. The storms will push east to the I-49 corridor by 9 to 11 PM to the Highway 65 corridor by 12 to 2 AM, then to Highway 63 by 2 to 4 AM and the main line of storms should push east of the area by 6AM, though some linger storms could occur across south central Missouri until closer to 8 AM. Again damaging straight line winds will be the main risk across the entire area with wind gusts up to 80 mph possible and a few short lived tornadoes mainly along and west of Highway 65. Hail up to half dollars and localized flash flooding will also be possible tonight. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 100 PM CDT Mon May 6 2024 Current Conditions and Synoptic Pattern: Water vapor and upper air analysis shows a strong upper level shortwave trough across Wyoming and Colorado with a 120kt upper level jet across Arizona and New Mexico. Surface low pressure continues to deepen across South Dakota with a secondary low across Kansas. A warm front was in the process of lifting north through the area at this time. A dry line was located across western Kansas and western Oklahoma with storms already initiating across northern Kansas. 12z KSGF sounding showed a stable airmass in place (north of the warm front) however soundings south of the warm front measured a moist and unstable airmass. Visible satellite showed breaks in the clouds across the area which should allow the warm front to continue lifting north. A few showers were occuring however many areas were dry with temps in the upper 60s to lower 70s. Dewpoints were also creeping up into the lower 60s. This Afternoon through early evening (1pm-8pm): The warm front will continue lifting north through the area and temps will continue warming up into the 70s which will increase instability. While a few showers and even a thunderstorm may develop, upper level forcing will still be to the west therefore many areas will remain dry. All eyes will be on developing supercells in a High Risk severe environment across southern Kansas and northern Oklahoma. These storms will begin to evolve into a line with time. Tonight (After 9pm): High res ensembles continue to be in good agreement that a line of severe storms will approach far southeast Kansas in that 9-10pm timeframe. RAP forecast soundings across southeast Kansas and western Missouri indicate around 1500j/kg of ML CAPE (potentially up to 2000j/kg) with 40kts of 0-6km shear (this will increase further with time). The 120kt 300mb jet will be nosing into the area tonight. Also of note is that 1.4-1.5in PW values which indicates a very moist airmass. All this leads to high confidence that storms will remain severe as they approach the area. Given the expected linear mode and high instability/shear combo, damaging winds of 60-80mph will be the most likely risk as highlighted in the SPC Moderate/Enhanced risk areas. That being said, any bowing segments to the east- northeast or northeast could cause brief tornadoes. We believe that the threat for supercells and significant tornadoes will remain just west of the area however if storms were slower to morph into a line then this expectation would change. Southeast Kansas will need to closely monitor storm mode tonight. The hail threat looks lower with this system given the linear mode however hail up to the size of half dollars will be possible. As the line moves further east (between I-49 and Highway 65), the damaging wind threat (60-80mph winds) and brief tornado threat will continue. Latest RAP sounding for Springfield between 11pm-1am still shows 1000-1500j/kg of ML CAPE with 40kts of shear. PW values are also in the 1.4-1.5in range which supports heavy rainfall rates. While it does look like storms will gradually weaken as they move east of Highway 65, the instability/shear combo will remain high enough to keep the damaging wind/brief tornado threat going however perhaps not as high a threat as areas further west. In general, the line of storms will likely be clearing the area by 5-7am. Overall a busy overnight period is expected with the increasing potential for widespread damaging winds. We will continue to heavily message safety information for this night time severe event. Contemplated a Flood Watch for areas west of Springfield tonight however given the progressive nature of this line, flooding will remain localized and brief. 12z HREF does show a few pockets of 1-2 inches of rainfall across far southeast Kansas therefore we will be monitoring this risk. Tuesday: The airmass will likely be worked over from overnight storms and combined with mid level height rises we should see low precip chances (less than 20 percent). Winds will turn southwesterly during the day with skies clearing and temps reaching the upper 70s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 100 PM CDT Mon May 6 2024 Wednesday: Another shortwave trough will move through the southern Plains with a surface front moving through the area during the afternoon or early evening. Strong instability will be available with the NBM mean showing between 2000-2500j/kg of surface based CAPE along and southeast of the I-44 corridor. This instability and unidirectional shear could produce supercell thunderstorms and the area is in a Enhanced Risk on Wednesday. There still remains uncertainty with frontal timing and since we are not in the window of time yet for the high res guidance it is urged to stay up on the forecast for Wednesday. Thursday into the Weekend: The overall trend during this time period is drier conditions and cooler temps. This is likely due to a pattern shift with northwest flow aloft causing north surface winds. Friday looks to be the coolest day with highs in the 60s in many locations. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 532 PM CDT Mon May 6 2024 Gusty southeasterly winds will continue this evening, some MVFR ceilings could occur, but mainly VFR conditions will occur. A few isolated showers and maybe a thunderstorms may be possible this evening but most locations will remain dry through 9PM. Storms have developed across central Oklahoma and Kansas early this evening. These storms will continue to move east and developing into a line or lines of storms. This activity will move into the area western portions of the area late this evening and through the rest of the area overnight. These storms will have the potential for damaging winds, frequent lightning and brief heavy rain. IFR to LIFR conditions will occur with the storms. The storms will move east from west to east overnight into early Tuesday morning. Winds will turn to more southwesterly behind the storms and remain gusty on Tuesday. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ MESOSCALE... SHORT TERM...Burchfield LONG TERM...Burchfield AVIATION...Wise