Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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882 FXUS63 KDVN 111948 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 248 PM CDT Sat May 11 2024 .KEY MESSAGES... - Quiet weather through Sunday morning. Clear skies expected tonight. - Sunday will be the warmest day of the next seven with highs in the lower 80s. Isolated to scattered storms are possible late Sunday afternoon into Sunday night. - Zonal flow across the CONUS will result in active weather continuing through the next week. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 206 PM CDT Sat May 11 2024 Confluent flow aloft over Upper Midwest this afternoon as 500 MB ridging builds into the area at the surface and aloft. Visible satellite imagery is showing some areas of diurnally driven cumulus developing across Illinois and parts of Iowa. The KDVN sounding showed a convective temperature of 69 degrees. Temperatures at 2 PM ranged from 69 degrees at Freeport and Dubuque to 76 degrees at Macomb. Northwest winds have been gusting up to 35 MPH at times this afternoon but in general winds are gusting up to 25 MPH. High pressure will move southeastward across the area at the surface and aloft through Sunday morning. This will bring quiet weather to the area overnight The HRRR and HREF have been showing some thinning high clouds moving across the area this evening but do not expect widespread cloud overnight with dry air in place. Winds will diminish tonight and become light and variable. Low temperatures will generally be around 50 north of a Independence to Clinton to Princeton Illinois line with lower to mid 50s south. On Sunday, the ridge axis will push to the southeast during the morning as one shortwave dives into Michigan. The ECWMF is the faster and farther south of the different solutions with the cool front approaching the area by 00 UTC Sunday. CAMs do have isolated to scattered showers and storms developing across the area from 20 UTC (3 PM) along the Highway 20 corridor. Model soundings show that brief gusty winds will be the main threat but moisture is very limited and soundings are showing inverted-V or onion sounding characteristics. Temperatures on Sunday will be in the lower 80s. Forecast soundings show the potential for gusty winds once again with a few gusts especially across northwest Illinois and far eastern Iowa near 25 MPH. Models have slowed precipitation moving into the area on Sunday in association with a closed upper level low moving from Colorado into eastern Kansas by 12 UTC Monday. The better chances of 30 to 40 percent will remain west of the Mississippi River overnight. Rainfall amounts will be light and range from one to two tenths. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 206 PM CDT Sat May 11 2024 The 500 MB flow will remain zonal through the upcoming week with an active northern (polar) and southern (sub tropical) branches of the jet streams across the continental US. This will result in several more chances for showers and storms. High temperatures will be in the lower to mid 70s through mid week before a warming trend beings into next weekend. Monday: An upper low on the northern periphery of the subtropical jet is forecast to slowly track from the Southern Rockies to the Lower to Mid Mississippi Valley early in the week. This will keep the local area on the cooler and more stable side of the surface low. Rain is likely to spread in from SW to NE during the morning and afternoon. NBM chances for measurable rain range from near 50% in the far NW corner of the outlook area to ~90% south of I-80. The 24 hour probability for 0.50" or more of rain reaches 50-70% south of I-80 and drops down to 20% near Highway 20. The NBM may still be running too warm for max temps due to the likelihood for widespread clouds and rain; these may need to be lowered by several degrees in later updates. Tuesday - Friday: There remains uncertainty with how fast the rain moves out on Tuesday. The ECMWF lingers the rain through the morning across the south half of the outlook area, while the GFS/CMC shift it to the SE more quickly. Our current forecast is leaning towards the latter scenario. Then it looks like we will get a break from the rain later Tuesday through Wednesday before the next shortwave trough and associated cold front arrive by Wednesday night into Thursday. Late week temps are forecast to be slightly above normal in the low/mid 70s. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1228 PM CDT Sat May 11 2024 High pressure will bring quiet weather and VFR flying conditions to the area through the TAF period. Currently, gusty northwest winds are forecast to diminish during the early evening hours. Winds will turn to the south after midnight as another storm system approaches the area. && .HYDROLOGY... Issued at 955 PM CDT Fri May 10 2024 The Flood Warning continues for the Wapsipinicon River near De Witt. The initial crest has come in considerably lower and below flood stage, so the river is now expected to go into Minor flooding on the evening of Monday, May 13th when the second crest due to routed flow occurs. Given how the initial crest was lower and attenuation of routed flow confidence is dropping a bit on the river reaching flood stage. The overall situation with the Cedar and Iowa Rivers is more uncertain. Flood watches remain in effect for Marengo on the Iowa river, and the Cedar River near Conesville. The Iowa River at Marengo is forecast to go into Minor flooding Sunday evening May 12, while the Cedar River near Conesville is forecast to go into Minor flooding early Tuesday morning, May 14. Rainfall over the next 72 hours and where it occurs will be the deciding factor as to whether or not the Cedar and Iowa Rivers will reach flood stage near Conesville and at Marengo respectively. If the rainfall is lighter than expected then river forecasts may be lowered. However, if rainfall is heavier than expected then river forecasts may be raised. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Cousins LONG TERM...Cousins/Uttech AVIATION...Cousins HYDROLOGY...McClure