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Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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401 FXUS63 KDVN 050003 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 703 PM CDT Thu Jul 4 2024 .KEY MESSAGES... - There is a marginal risk (level 1 out of 5) of severe storms along and north of Interstate 80. There is a slight risk (level 2 out of 5) for Buchanan County. - Wrap around rain showers are possible through the day on Friday. - Several rounds of showers and storms are possible in or near the area Saturday night through Monday. - Moderate to Major River Flooding continues, with further changes to river forecasts expected as we transition from predicted rainfall to observed rainfall over the next 36 hrs. && .UPDATE... Issued at 700 PM CDT Thu Jul 4 2024 CAM`s models struggling with convective trends early this evening. Line of storms in northeast IA has developed as far south as Iowa Falls but the models had the line down to Des Moines. SPC mesoanalysis shows modest mid level lapse rates and h8 winds of only 10-15 kts. In addition, we will soon be past our peak heating so a gradual weakening trend is expected. As of now, our best confidence in thunderstorms in the DVN forecast area is along the Highway 20 corridor through this evening. Trends indicate the storms reaching Dubuque about 10 pm. The window for storms only will last a couple of hours. Much of the forecast area appears to remain dry for this evenings fireworks festivities. Will be updating pops. Cold front in western IA will push across our area later this evening into the overnight hours with west to northwest winds behind the front, then cooler and less humid on Friday. && .SHORT TERM /THROUGH FRIDAY/... Issued at 255 PM CDT Thu Jul 4 2024 At 1 PM, scattered showers are moving eastward across far eastern Iowa into northwest Illinois. These showers are producing light rainfall at times. Temperatures range from 75 degrees at KAWG and KCID to 80 degrees at KMQB. Dewpoints across the area are in the upper 60s to lower 70s. Scattered showers are forecast to exit to the east by mid afternoon as shortwave exits into eastern Illinois with some clear skies behind the showers resulting in a few hours of warming across the area. Convective Allowing Models (CAMs) show CAPE increasing to 500 to 1500 J/KG into this evening ahead of a shortwave that will move across the area after 00 UTC. Models show sufficient shear across the area for severe thunderstorms with 45 to 55 knots across the area this evening. The marginal risk (level 1 out of 5) has been shrunk to along and north of Interstate 80 today. There is a slight risk (level 2 out of 5) for Buchanan County. CAMS show storms developing in north central Iowa by late afternoon ahead of a cold front and moving southeastward across our eastern Iowa counties after 7 PM and then exiting our northwest Illinois counties after 1 AM. There is still some uncertainty in the southward extent of showers and storms tonight so for now the best chances are along and north of Interstate 80. Think that the main threats are hail and damaging wind gusts. Models show the cold front exiting the area prior to 12 UTC on Friday. Low temperatures tonight are in the mid 60s across the area. The 500 mb trough and closed low are forecast to slowly move eastward through the day on Friday from northeast Iowa into Lake Michigan by 00 UTC Saturday. This will result in 20 percent chance of wrap around rain showers through the day on Friday as cooler air aloft and lift allow showers to grow quickly. High temperatures on Friday are forecast to be in the mid to upper 70s. Gusty west winds are forecast to develop Friday morning with speeds of 10 to 15 MPH and gusts up to 25 MPH. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Issued at 255 PM CDT Thu Jul 4 2024 Dry conditions are expected late Friday night through Saturday, as the upper low moves east of the area and high pressure builds in behind it. Saturday night through Monday, the high will then exit east with a trough setting up in the plains. Several waves will move across the region during this period. The first wave with better precip chances clips our NW half of the CWA Saturday night into Sunday. The second comes over Sunday night into Monday and then a third with the cold frontal passage later on Monday. There are some timing and placement differences, but the higher POPs in the general time frames mentioned above seem to be on track. Temperatures will average slightly below normal with highs in the upper 70s to low 80s through Tuesday. Tuesday into Wednesday looks to be mostly dry with low end POPs returning for Wednesday afternoon. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 648 PM CDT Thu Jul 4 2024 Basically a VFR forecast for much of this taf cycle. The exception is at KDBQ where thunderstorms will bring IFR conds for a couple of hours (03-05z/05). A cold front in western IA will move across the taf sites later this evening and overnight, with west to northwest winds behind the front. CAM`s models seem too far south with the line of storms in northern IA. The best confidence in where storms occur later this evening is along Hwy 20 so have a TEMPO group at KDBQ. Have kept the remainder of the taf sites dry. We will continue to monitor convective trends and amend if necessary. && .HYDROLOGY... Issued at 255 PM CDT Thu Jul 4 2024 The forecast crests along the Mississippi River have been delayed and are now showing a longer duration crest at several locations due to some rainfall and forecast rainfall upstream. Most of the crest values have been steady or only minor changes. Major flooding will be seen across much of the Mississippi River with long duration crests occurring after July 7th. Keokuk is expected to get to the Major Flood stage near the 7th or 8th, and Gregory Landing is expected to crest in its Moderate flood category. Tributary Rivers: Over the next 7 days, Moderate flooding will continue on the Wapsi at Dewitt and minor flooding will continue at Conesville on the Cedar River. Wapello on the Iowa River is expected to drop out of flood late Sunday. At Oakville, backwater from the Mississippi will keep the level high, in minor flooding, through July 11. Current projections for additional rainfall through July 10th appear to be spotty with widespread heavy rain not anticipated at this time. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ UPDATE...Haase SHORT TERM...Cousins LONG TERM...14 AVIATION...Haase HYDROLOGY...14