Area Forecast Discussion
Issued by NWS Springfield, MO
Issued by NWS Springfield, MO
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978 FXUS63 KSGF 081737 AFDSGF Area Forecast Discussion National Weather Service Springfield MO 1237 PM CDT Wed May 8 2024 .KEY MESSAGES... - Severe thunderstorms expected today with very large hail up to the size of baseballs, damaging winds up to 60-80 mph, and tornadoes. First round in the morning to mid afternoon with round two in the late afternoon and evening. Highest potential for severe storms along and southeast of a Joplin to Warsaw line. - Localized heavy rainfall may result in flooding, especially for areas northeast of a line from Stockton to Marshfield to Eminence. A Flood Watch has been issued for this area, where storms may drop 1 to 3 inches of rain with locally higher amounts of 3 to 6 inches. - Drier and cooler conditions for late week and weekend. && .MESOSCALE... Issued at 1218 PM CDT Wed May 8 2024 A warm from was located across central Missouri and was a focus this morning, and will continue to be, for storms into this afternoon. A cold front was also located across eastern Kansas into eastern Oklahoma. This places the Ozarks and far southeastern Kansas in the warm sector this afternoon. Several boundaries have been notes on satellite across the region as well thanks to earlier convection, differential heating from cloud cover and other small scale waves. The region has seen temperatures increase to around 80 degrees with Td`s around 70. This is helping to produce a favorably unstable airmass over the area. Models as indicating between 2500-4500 J/kg of CAPE with little to no CAP over the region. The latest runs show 0-6KM Bulk shear in the 40-50kt range from the WSW with a 35 to 45kt LLJ over the region. This is accompanied by upper level support from a strong 250mb Jet streak. As a result, A Tornado Watch is in effect until 00z (7PM) with the potential for large hail, to baseballs in size, with 1000-1300 j/kg of CAPE in the hail growth zone (-10 to -30 *C). This, coupled with a relatively long straight Hodograph support, supercells with splitting cells possible. Winds from 60 to 80 mph will also be possible along with tornadoes. && .SHORT TERM /THROUGH TONIGHT/... Issued at 430 AM CDT Wed May 8 2024 Focus is on potential for significant severe weather this morning through this evening. Expecting two rounds of severe storms: Round 1: Strong southerly flow is pulling moisture northward quickly. A cloud deck can be seen on satellite over southeast OK into central AR, which will arrive over the southern CWA around 11Z, which is right in line with what models have been showing. This moisture, along with the nose of the strong LLJ moving east toward the area and a surface warm front will be the catalyst for the development of elevated thunderstorms as early as 6 AM over the western CWA. Models show uncapped elevated instability rapidly developing early this morning, with 2,000-3,000 J/kg of CAPE developing by 12Z when lifting from the 850mb. Expectation is for this elevated convection to rapidly become severe with very large hail (golf ball or larger) being the primary risk and damaging winds being the secondary risk. Expect these storms to increase in coverage and push east through the northern half of the CWA this morning into mid afternoon as multicell clusters or perhaps growing upscale to an MCS. These storms should stay along and north of the warm front, which should stall in an east-west orientation somewhere over the central CWA, but confidence is limited in exact location. If storms don`t form into an MCS, there is a concern that storms sticking to the warm front over the eastern CWA may be able to root near the surface and ingest helicity from the front, resulting in a tornado threat. This would be especially true if the front orients in a straight west-east line or in a WNW-ESE line, which would cause storms to move even more to the right of the right moving storm motion today and increase storm relative inflow. If ideal storm mode and frontal interaction occurs, significant tornadoes could result but that is a very conditional threat. South of the warm front, surface based storms should hesitate to form through early to mid afternoon. However, if storms do develop south of the front they could quickly become severe with primarily a very large hail and damaging wind threat. Guidance shows repeated development of elevated storms over portions of central MO (NE CWA) this morning into the afternoon, which may result in flooding. 00Z HREF LPMM shows potential for locally up to 6 inches of rain through this afternoon. Have issued a Flood Watch to cover this threat. Round 2: A cold front will push through the area late today, initiating additional convection over the western CWA late this afternoon and pushing that through the southeastern CWA by midnight tonight. These storms look to be more discrete supercells that will have access to a very unstable environment (SBCAPE of 3,000-4,000 J/kg) and deep layer shear around 50 kts. Initially, wind fields will be more unidirectional, which will favor baseball (if not larger) size hail and 60-80 mph winds as the primary risks NW of I-44. Models have been trending slower with the eastward progress of these storms, which is problematic for areas SE of I-44 because we are also seeing a trend to having better shear profiles in the evening and potentially some backing surface winds. Latest RAP and HRRR both show arcing hodographs that lead to 0-1km Helicity increasing to 200-300 M2/S2 and Significant Tornado Parameter values of 5-10. A lot could happen to disrupt this tornado threat, but if ideal conditions present themselves as shown by the RAP and HRRR, a significant tornado threat could result south of I-44 this evening. Stay tuned for updates through the day. Additional significant threats of baseball or larger hail and 60-80 mph winds are also expected south of I-44. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 430 AM CDT Wed May 8 2024 Thursday through Saturday looks dry, with chances for rain increasing Sunday into Tuesday. Temperatures will be near normal. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1218 PM CDT Wed May 8 2024 Through 00z to 03z or slightly later, the regions terminals may be impacted by strong thunderstorms. Away from storms flight conditions will be MVFR with brief periods of VFR conditions. Ceilings will be the primary concern. Where storms occur, flight conditions will deteriorate quickly with MVFR to IFR conditions. Airfields may see high wind and hail impacts with the strongest storms. The storm system will progress through the region likely by 03z though some light precipitation may linger. However, behind the storms, flight conditions will improve to VFR as ceilings lift and cloud cover becomes scattered to few. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...Flood Watch until midnight CDT tonight for MOZ055>058-067>071- 078>083-091-092-098. && $$ MESOSCALE...Hatch SHORT TERM...Titus LONG TERM...Titus AVIATION...Hatch