Area Forecast Discussion
Issued by NWS Springfield, MO
Issued by NWS Springfield, MO
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860 FXUS63 KSGF 120808 AFDSGF Area Forecast Discussion National Weather Service Springfield MO 308 AM CDT Wed Jun 12 2024 .KEY MESSAGES... - Warm-up starts today with temperatures reaching the 90s by Thursday into early next week. Heat index values generally in the mid 90s to around 103. - Low end thunderstorm chances on Thursday night(15-30%) as a front sags south into the area. && .SHORT TERM /THROUGH TONIGHT/... Issued at 133 AM CDT Wed Jun 12 2024 Current observations put the center of a weak surface high pressure system over our region, creating weak and variable winds and mostly clear skies. Some scattered upper-level cirrus are present as a very weak mid- and upper-level disturbance traverses AR, as noted by water vapor imagery. This disturbance is embedded in weak upper-level flow as the polar jet stream remains across the US/CA border. With the jet stream well to the north, a summer pattern is beginning to settle in that will bring warmer temperatures to our region. Warm-up starts today: As the surface high pressure shifts eastward today, SSW`ly flow will overtake the region, advecting in warmer air. Additionally, 850 mb warm air advection across the Rocky Mountain front range and into the central Plains will act to amplify a longwave ridge across the Four Corners Region and into the southern Plains. This pattern will slowly move eastward, allowing for a gradual warming trend across our region, starting today. Clear skies and 17-20 C 850 mb temperatures overspreading the region will allow high temperatures to warm into the middle to upper 80s today after experiencing cooler morning temperatures around 60 F. As night falls, the ridge axis will be over NM with NW`ly upper-level flow over MO. Beneath this flow, an 850 mb temperature gradient will be present with warmer temperatures toward KS. This will support lows near 60 F in the eastern Ozarks and near 70 F along the MO/KS border. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 133 AM CDT Wed Jun 12 2024 Temperatures will reach the 90s by Thursday: The longwave pattern will continue to slowly shift eastwards Thursday, creating height rises across our region as the ridge axis shifts over the NM/TX border. A tongue of warmer 850 mb temperatures will follow suit as 20-22 C temperatures advect into southern MO. This, paired with clear skies, will allow high temperatures to warm into the upper 80s and lower 90s. Areas above 90 F will generally be off the Ozark Plateau (toward central MO and the KS/MO border). Additionally, moist gulf air will also continue to be advected into the region with SW`ly flow behind the exiting surface high pressure system. Dewpoints are expected to reach the upper 60s and lower 70s, making for a muggy day. Nighttime temperatures will also be quite mild with lows in the upper 60s and lower 70s. 15-30% thunderstorm chances Thursday night: All while this ridging develops to the southwest, an upper-level shortwave will traverse the upper Great Lakes, forcing a surface cold front to sag southward. With such a humid airmass forecast to be in place, thunderstorms are expected to develop Thursday afternoon ahead of the front in southern IA/northern MO. The front is expected to slowly sag southward through the night, bringing thunderstorm chances with it. The front should stall somewhere over central MO late Thursday night which introduces the 15-30% chance of thunderstorms over our far northern counties (north of Hwy 54). Medium range models suggest that there could be upwards of 3000 J/kg of MUCAPE just ahead of the front, though inhibition will be quite high. So any storms that do happen to make it into our CWA late Thursday night will likely be elevated, but given moderate to high CAPE and 30-40 kts of 0-6 km bulk shear, isolated marginally severe wind gusts (up to 60 mph) and hail (up to quarter-size) would be possible. Heat Index values between 90-103 through early next week: With the upper-level shortwave quickly exiting off to the NE states and the ridge continuing to build eastward, the cold front across central MO will quickly dissipate Friday. The longwave riding pattern will continue to slowly traverse eastward with the axis over our region Saturday night into Sunday, and the western edge of it exiting our region by Wednesday. This will allow daily high temperatures in the lower to middle 90s and lows in the lower to middle 70s. The hottest day is looking to be Sunday when the ridge axis is over our region (highs near 95 F and lows near 75 F). Confidence is quite high that high temperatures will be in the 90s as NBM spreads are quite small. A lower end scenario would have highs only down into the upper 80s and an upper-end scenario is generally between 93-95. There are scenarios that high temperatures exceed 95 F since the NBM is likely being slightly bias corrected from the past week. This would be especially true on Sunday where highs could reach the record (see the Climate section below for more details). For example, 45% of NBM models depict Joplin breaking its record high of 95 F Sunday. Of additional concern will be the humidity paired with the heat. An open gulf will keep dewpoints hovering around 70 F everyday. ESATs are marking the upcoming days to have >90th percentile temperatures and specific humidity, furthering confidence in multiple muggy days. The high temperatures and humidity will bring Heat Index values into the middle to upper 90s, and sometimes exceeding 100 F. Generally clear skies and somewhat subdued winds will also bring Wet Bulb Globe Temperatures into the middle 80s, which for our region brings the recommendation of several breaks per hour when working outdoors, as heat stress will be elevated. Additionally, since this will be the first prolonged abnormal warm period, the heat and humidity may be more impactful to some people. HeatRisk is suggesting areas will be in a Major risk for heat-related impacts Saturday through Tuesday. When required to be outside, taking extra breaks, having effective cooling, and being adequately hydrated is highly recommended. Rain chances Saturday into Sunday?: As the western edge of the ridge creeps into our region over the weekend, there is a signal for a shortwave to lift just west of the region. This could bring the possibility for rain chances, though confidence is too low at the moment to introduce chances greater than 15%. As details become clearer in the coming days, these chances could increase. Moderate Excessive Heat Risk (6/19 - 6/23): In the extended range, the WPC is giving a moderate risk for excessive heat between Wednesday, 6/19 and Sunday, 6/23 (40% chance). This is a result of global ensembles giving a signal for an amplified ridge and subsequent high pressure to build over the eastern CONUS. Trends will be monitored as this enters our forecast range, but this is meant to be a heads up call to prepare for more heat later this month. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1224 AM CDT Wed Jun 12 2024 VFR conditions will prevail through the entire TAF period with light winds generally out of the SSW. SCT high clouds will clear by 12Z. While SKC is the prevailing category through the rest of the TAF period, some FEW to SCT cumulus clouds at around 5 kft are possible between 18-01Z. && .CLIMATE... Issued at 501 AM CDT Mon Jun 10 2024 Record High Temperatures: June 16: KSGF: 97/1952 KJLN: 95/2016 Record High Minimum Temperatures: June 15: KSGF: 74/2022 June 16: KSGF: 75/2022 June 17: KSGF: 76/2016 && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Price LONG TERM...Price AVIATION...Price CLIMATE...Price