Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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585 FXUS63 KDVN 060517 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1217 AM CDT Sat Jul 6 2024 ...Updated for 06z Aviation... .KEY MESSAGES... - Isolated to scattered showers ending this evening. A brief funnel cloud may occur in any strong updraft of a developing shower or thunderstorm. - Moderate to major river flooding continues. - Periodic rain chances late this weekend and into early next week with temperatures slightly below normal. && .SHORT TERM /THROUGH TONIGHT/... Issued at 228 PM CDT Fri Jul 5 2024 The upper level disturbance producing the showers and possibly a couple of rogue thunderstorms will move into the Great Lakes tonight. The loss of forcing means that the showers will quickly dissipate with sunset leaving a dry overnight for the area. While not certain, brief funnel clouds could occur late this afternoon in any strong updraft of a developing convective cell. Saturday will be dry with temperatures slightly below normal as high pressure quickly moves through the Midwest. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 228 PM CDT Fri Jul 5 2024 Saturday night through Tuesday Assessment...medium confidence Return flow develops Saturday night but moisture is initially lagging. The moisture associated with the upper level disturbance should be enough to generate isolated to scattered showers late Saturday night into Sunday along with a few thunderstorms. Coverage looks to be in the 30-40 percent range so some areas will probably remain dry. A secondary upper level disturbance arrives Sunday night into Monday. Interestingly a couple of the global models are attempting to connect the moisture from this disturbance with the tropical moisture of Beryl. If this scenario occurs, then the Sunday night into Monday time frame would hold the better chance of rain (50-60 percent) for the area. Monday night into Tuesday is more in question regarding the rain chances. From the large scale picture the better moisture is shunted off to the east which would indicate little if any rain occurring as an upper low drops into the Midwest. However, there are several ensemble members from the various global models generating precipitation for the area. The model consensus does carry a risk of rain (generally 20-35 percent) for Monday night and Tuesday. However, unless there is additional moisture for the upper low to work with, the overall areal coverage of any rain could be much lower. Thus the message is that while there is a risk of rain Monday night into Tuesday, the probability of dry conditions for much of the area is much higher. Tuesday night through Friday Assessment...medium to high confidence The model consensus has mainly dry conditions through the period with the exception of Wednesday. On Wednesday another upper level disturbance will move through the area. If sufficient moisture is available, the overall forcing will induce diurnal showers and thunderstorms. There are some ensemble members suggesting dry conditions on Wednesday but a majority indicate some rain is possible. The overall coverage will be on the light side (20-30 percent) so much of the area may remain dry. The wildcard in all this is the remnants of Beryl and its associated tropical moisture feed. Right now the global models are indicating that the tropical moisture will pass well south of the area. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1210 AM CDT Sat Jul 6 2024 VFR looks to be predominant through the TAF cycle, although periods of MVFR ceilings and/or visibility is possible toward daybreak and through Saturday morning mainly at KDBQ between valley fog and some advective potential of stratus from southern Wisconsin. Can`t also rule out a very brief MVFR ceiling at KMLI mid to late morning before mixing promotes lifting of cumulus bases. Late in the period we may see some convection approach eastern Iowa, but the better potential exists primarily after 06z-12z Sunday for portions of the area. Winds will remain light throughout generally favoring from a W/NW direction today, then becoming southerly tonight. && .HYDROLOGY... Issued at 1141 AM CDT Fri Jul 5 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 in timing. Major flooding is forecast along most of the Mississippi River. 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 Wapsipinicon River at Dewitt and minor flooding will continue at Conesville on the Cedar River. A flood watch remains in effect for the Cedar River at Cedar Rapids due to rises from routed flow and forecast rainfall. Wapello on the Iowa River is expected to drop below minor flood stage this afternoon. At Oakville, backwater from the Mississippi will keep the level high, in minor flooding, through July 11. Within banks rises are occurring on the English River at Kalona and on the North Skunk River at Sigourney. Over the next seven days widespread heavy rain is not expected. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...08 LONG TERM...08 AVIATION...McClure HYDROLOGY...Cousins