Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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194 FXUS63 KDVN 312229 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 529 PM CDT Fri May 31 2024 ...Updated for 00z Aviation... .KEY MESSAGES... - Mainly dry and continued pleasant into early tonight. - Chances for showers (40-80%) from late tonight (and possibly a few storms) into Saturday. - Active pattern next week, with near daily chances for showers and storms. May have to watch Tuesday into Wednesday for a chance of stronger storms. && .SHORT TERM /THROUGH SATURDAY/... Issued at 145 PM CDT Fri May 31 2024 Quiet and comfortable weather is expected this evening into early tonight with dry conditions and temperatures falling from the 70s into the 60s. An open mid-level wave is forecast to track across the Mid Mississippi Valley region late tonight into Saturday, bringing light rain to much of eastern Iowa and northwest Illinois. Despite weaker forcing aloft, isentropic lift to the northeast of the shortwave and persistent lower tropospheric moisture advection will result in periods of light rain or occasional showers. The activity will spread in from south to north, reaching NW sections of the outlook area the latest. The steadiest rain is anticipated for the counties approximately along and east of the Mississippi River where chances peak in the 60-80% range. Across the NW counties, probabilities drop off to 30-40%. Gulf of Mexico moisture advecting northward along the eastern periphery of the low will push PWATs to near 1.5", and when combined with the relatively long duration of forcing, some areas in eastern to southeast counties may pick up over a half inch of rainfall. Outside of the heaviest swath of rain, anticipate much of the area to receive between 0.10 - 0.40". There is a slight chance for embedded thunder late tonight into Saturday morning; however, mid-level lapse rates are only near 6 C/km and HREF MUCAPE is on the order of a few hundred J/kg. As diurnal instability increases during the mid/late afternoon, a few isolated storms may develop with no severe weather expected. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Issued at 145 PM CDT Fri May 31 2024 A brief bout of 850 hPa ridging builds in Sunday making for largely dry conditions. However, by Sunday night the high will quickly retreat and isentropic lift will rapidly strengthen ahead of an emerging shortwave in the Central Plains. The brunt of the low level jet and attendant advection and convergence looks to focus mainly to our west, but nonetheless will expect shower and storm chances to ramp up late Sunday night through Monday AM with a veering jet and passing shortwave. For much of early to mid next week the pattern looks to become predominantly fast zonal. This will keep the weather active across the region, as multiple disturbances are shuttled quickly in the flow. There is considerable differences in timing, strength and placement of these waves in deterministic and ensemble guidance, as to be expected given many of these are low amplitude. As a result, we continue to have many days of broad- brushed and higher PoPs while in reality it favors smaller windows or time periods of high PoPs with still many dry hours. A stronger mid level shortwave by mid next week may provide the opportunity for some stronger storms Tuesday into Wednesday. CSU`s machine learning guidance is highlighting much of the Upper Mississippi Valley with a strong to severe thunderstorm threat for Tuesday/Tuesday night, the details of which are unclear this far out. Beyond that, it looks to turn cooler while remaining unsettled heading into late next week and next weekend, as the preponderance of the deterministic and ensemble guidance supports a cut-off low traversing the Midwest and Great Lakes regions. This will foster continued periodic chances for showers, as spokes of energy rotate around the low. The clouds and eventual northwest flow aloft will favor cooler conditions. The Climate Prediction Center (CPC) Week 2 temperature outlook for June 7-13 has probabilities (40-50%) leaning toward below normal temperatures. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 523 PM CDT Fri May 31 2024 VFR conditions to start the period will gradually deteriorate areawide tonight into Saturday morning, as weak low pressure moves into the area. Showers and isolated thunderstorms (low chance around 20%) will accompany the low, with high confidence (50-70%) of MVFR ceilings and visibilities with them. Brief bouts of IFR conditions may be possible during the late morning in heavier showers, mainly at KBRL and KMLI. Winds will remain light out of the east to southeast throughout the period. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Uttech LONG TERM...McClure AVIATION...Speck