


Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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869 FXUS63 KDVN 150816 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 316 AM CDT Tue Jul 15 2025 .KEY MESSAGES... - Dangerous heat Wednesday, with afternoon heat indices near or just above 100 degrees along and south of I-80. - There is a Slight (level 2 out of 5) Risk for severe storms and excessive rainfall Wednesday afternoon and evening. Damaging winds, heavy rain, and a low risk for tornadoes are the primary threats. - Active weather pattern expected late week and into the weekend with periodic chances of showers and storms. - Extreme heat possible next week, with heat indices over 100 degrees at times. && .SHORT TERM /THROUGH TONIGHT/... Issued at 308 AM CDT Tue Jul 15 2025 Clear skies and mild conditions were seen early this morning, as the region sits in-between systems and weak high pressure remains centered over northern MO. Temperatures and dewpoints at 2am were mainly in the upper 60s. Southwesterly flow aloft will be in place today with a compact shortwave passing to our south this afternoon. Some diurnal Cu to develop along and east of the MS RVR. Otherwise, dry conditions and afternoon temperatures topping out a few degrees warmer than yesterday in the upper 80s/low 90s. Dewpoints in the low 70s (thanks in part to mature crops) will keep it muggy outside with heat index values in the mid to upper 90s. In fact, if you haven`t noticed it has already been quite humid this summer. An interesting climate fact that I came across this morning is at MLI/Quad City Airport there has been at least 1 hour each day of a dewpoint of 65 degrees or greater since June 12th! This is the 2nd most consecutive days (33 total days) in a row dating back to 2000, with only July 4th through August 10th in 2010 having a longer stretch (43 days). Going back to the forecast today, latest CAMs have a few scattered showers/isolated storms forming after 22z primarily in central IL, but could see some activity developing across are far eastern CWA prior to sunset. Deep layer shear will be the limiting factor and am not anticipating any severe weather. Brief downpours and gusty winds will be the main hazards. Tonight...a stronger upstream shortwave will track across the Dakotas and western IA supporting strong to severe storms in this region. Instability will wane through the overnight period, thus this activity should diminish as it moves east over IA. Lows to drop into the upper 60s/low 70s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 308 AM CDT Tue Jul 15 2025 Wednesday...an active period of weather is expected with dangerous heat and severe potential the main concerns. Decaying storms are forecast to start the period with an increase in cloud cover. The amount of clouds during the day will play a key role in how warm we get and how much instability will be available for afternoon and evening storms. Will address each hazard below separately. Heat Potential A very warm and humid airmass will be in place characterized by mid-70 dewpoints. These values combined with forecast ambient temps in the upper 80s/low 90s to yield heat indices in the upper 90s and perhaps a few 100+ degree values during the afternoon. At this time, the probabilities for 100+ degree heat indices is highest (20-30%) along and south of Hwy 34. A heat headline may eventually be needed or at the very least an SPS on Wednesday. Severe Potential Latest CAMs and RAP model trends continue to suggest the potential for an MCV to track across the CWA resulting in strong to severe storms Wednesday afternoon and evening. In addition, a cold front is progged to move through after 23z providing another focus for thunderstorm development. A favorable thermodynamic environment (1500-2500 J/Kg ML CAPE and very high PWs over 2") will be in place ahead of these features. The limiting factor will once again be shear with 0-6km values under 30 kts. That all being said, if an MCV develops and maintains across eastern IA then shear can be locally enhanced in close proximity to it thereby increasing the severe potential. As a result, SPC has introduced a Slight (level 2 out of 5) risks for severe weather Wednesday. A few organized multi-cell clusters with damaging winds and a tornado or two will be possible. Very weak mid-level lapse rates under 5.5 C/Km to preclude any hail threat. In addition, WPC has added an Day 2 Slight risk for excessive rainfall with rain rates over 1"/hr possible on top of saturated ground leading to localized flash flooding. This risk is highest along and north of Hwy 30 as depicted by the 00z HREF. The one thing that is different of this event than compared to last Friday is the storms are expected to be progressive and have storm motions over 20 kts leading to less residence time at any given location and may limit any flash flooding. Thursday-Monday...an active pattern remains likely with a strong upper level ridge setting up shop across the southeastern CONUS. This will put the local area on the edge of the main storm track with several shortwaves rounding the ridge every 36-48 hrs. Not every day will see rainfall, but warm and humid conditions will bring a continued risk for afternoon storms. The next best chance (40-55%) of storms appears to occur this Saturday and Sunday. Tuesday Onward...some longer range guidance and the latest CPC 8-14 Hazards Outlook shows a building strong upper ridge developing across the central CONUS pushing the storm track further north, but unfortunately bringing even warmer air into the region. Extreme heat may be a growing concern as we enter next week. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1140 PM CDT Mon Jul 14 2025 Model guidance continues to suggest some brief MVFR fog will be possible prior to sunrise and have included TEMPO groups with the TAFs. Otherwise, VFR conditions to prevail at all terminals with the region remaining between systems. Some fair wx Cu should develop along and east of MS RVR this afternoon. A few shallow storms may also occur but all new guidance keeps this activity east of the terminals late afternoon/evening. && .HYDROLOGY... Issued at 1226 PM CDT Mon Jul 14 2025 The flood warning for the Skunk River at Sigourney has been canceled as the river has crested near action stage and has started to slowly fall. There have been no other forecast changes with flood warnings remaining in effect for the Iowa River at Marengo as well as the Mississippi River at Gladstone and Burlington. A flood watch remains in effect for the Wapsipinicon River at DeWitt. Within bank rises continue on several area rivers. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Gross LONG TERM...Gross AVIATION...Gross HYDROLOGY...Cousins