Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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610 FXUS63 KDVN 130838 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 338 AM CDT Thu Jun 13 2024 .KEY MESSAGES... - Potentially a significant severe weather day today across portions of the area with all severe risks in play. - Unseasonably warm temperatures will continue to be re-enforced into the area, especially today and late in the upcoming weekend into early next week. Heat Index readings today, Sunday and Monday may range from 95 to 100 in some locations. && .SHORT TERM /TODAY THROUGH TONIGHT/... Issued at 330 AM CDT Thu Jun 13 2024 Today...Ongoing isolated to wdly sctrd elevated showers and storms should fade this morning with diurnal interruption of LLJ feed. Then full on warm sector re-invigoration commences later this morning and into midday with elevated debris clouds fizzling after sunrise to lee of upstream cool front. But the north may get in on some high based decaying debris off the now occurring SD convection. THe cool front was seen now on sfc observations sagging southeastward along the ND/NE border region and up through east central MN. Then ongoing EML/cap to keep a lid on most activity into early afternoon, allowing for a heat up into the upper 80s and lower 90s acrs the southern 3/4`s of the DVN CWA. This combined with pre-frontal sfc DPT pooling into the upper 60s to low 70s, will make for afternoon Heat Index readings ranging from 95-100 south of I-80. The thermal build-up(as long as the above mentioned convective debris clears early enough) will lead to very high MUCAPEs of 3000- 4000+ by mid afternoon along and south of I-80. This as the upstream cool front pushes through this axis, a short wave digs acrs the region out of the northern plains, and a mid to upper level jet max south exit edge streams acrs the MN/IA border region. Continue to think these forces will break the EML hold and allow for explosive buoyancy release in the form of strong to severe convection, but how far north or south this axis occurs is still a bit uncertain. Some CAMs suggest initial development may occur post- frontally and be somewhat elevated again as the CAP erodes to the north of the boundary mid to late afternoon in the northern CWA. Then other storms may then fire in the more conceptual axis along the frontal scooping forcing along the boundary by late afternoon which may occur well south of I-80 from southeastern IA and toward the southern tip of LK MI. Other cap erosion processes may then allow post-frontal strong storms to pop acrs central into eastern IA, with all these clusters and cells then propagating south toward the high THTA-E pool acrs KS-MO-central IL as the evening progresses, aided by cold pool mechanics and becoming prolific damaging wind machines. Storm layer shear of 50-60 KTs and available CAPEs should allow for initial supercell structures, then evolving into bowing clusters as the evening progresses. Currently progged shear and thermodynamic profiles supports SPC`s very large hail potential, but the warm thermal profiles up to the mid levels may limit the bigger stones to golf balls or less as opposed to the advertised baseballs. Wind mix- downs by RFD`s or cold pool evolution support straight line winds up to 80 MPH in the mature bows or downbursts, and of course in these environments of lowered LCL`s a tornado not out of the question despite less than favorable LLVL shear away from any boundary. PWAT pooling up to near 2 inches by this afternoon and evening also support very heavy rainfall at high rates of 2-3 inches an hour as the storms pass by. Thus an isolated flash flood chance in a few areas that get hit a couple of times. Otherwise hopefully storm propagation speeds will limit the flooding threat. SPC`s Enhanced Outlook looks on target for those areas that manage to get in on or impacted by the organized storms as they mature. It`s just where this prime axis lays out...shear profiles interacting with max Deep Convective Index parameters suggest this axis to occur from northeast KS...acrs the southern DVN CWA, and to east central/northeast IL around 00z this evening. Tonight...Storms to clear off to the south and allow for post frontal cooling with northwesterly boundary layer flow advecting temps into the low 60s to mid 50s by Friday morning. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 330 AM CDT Thu Jun 13 2024 Friday...Still looking like a decent summer day in the wake of what ever happens today, with backdoor high pressure and seasonably warm temps along with lowered humidity. Saturday through Wednesday...Medium range ensembles still paint the picture of thermal ridging trying to build from upstream and into the region this period, and eventually getting implanted for higher heat and humidity by early next week. But this process to be a continued battle of incoming thermal ridge and heat, with ridge- riding MCS storm track potential close by for occasional storm cluster/MCS chances, especially at night Sat through Monday. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1245 AM CDT Thu Jun 13 2024 Isolated to sctrd elevated showers and thunderstorms will move southeastward acrs the area and in the VCNTY of most TAFs except maybe BRL through 11z this morning. They may produce brief passing b outs of MVFR conditions but still appears to be mainly a VFR late night into Thu morning for more areas than not. South to southwesterly sfc winds into Thu morning before a sfc front squeezes in from the northwest and will act as the focus for strong thunderstorm development by mid afternoon. The axis of development still somewhat uncertain on how far or north the storms develop, but along or just south of the I-80 corridor still looks favorable at this time. The storms should then propagate southeastward with high impacts to aviation ports with strong winds, hail and variable strong sfc wind gusts as they pass acrs any terminal. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...12 LONG TERM...12 AVIATION...12