Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
322 FXUS63 KDVN 130530 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1230 AM CDT Sat Jul 13 2024 .KEY MESSAGES... - Isolated to scattered showers and thunderstorms are possible overnight into Saturday morning, and again Saturday night. - Becoming hot and humid this weekend and into early next week, with heat indices in the upper 90s and low 100s. Heat headlines have been issued in the south for tomorrow afternoon, and will likely eventually be needed for Sunday and Monday for portions of the area as well. - Ring of fire pattern second half of the weekend into early next week may bring strong/severe thunderstorms close to the forecast area and temporary relief from the heat. Then there will be longer lasting relief in the form a significant cold front by mid week. - Moderate to major river flooding continues on the Mississippi River with most sites already have crested, or cresting in the coming days. && .SHORT TERM /THROUGH SUNDAY/... Issued at 251 PM CDT Fri Jul 12 2024 Tonight...Southeasterly return flow continues to west of GRT LKS sfc ridge, with higher sfc DPT fields noted off to the west and south of the area ready to slosh this way through tomorrow. The latest sfc analysis and MSAS were indicating a west-to-east oriented quasi- stationary boundary acrs northern KS and northern MO, which will look to trend into a retreating warm front with increasing southerly flow push later tonight and especially Saturday. A low chance for an isolated pop-up shower or storm in initial somewhat elevated WAA push in the cumulus field along and south of the CWA this evening. For now will keep silent POPs for this, and focus on the elevated warm air advection(WAA) wing later tonight after midnight for isolated to wdly sctrd showers and storms. Enough mid layer MUCAPEs of 1500-2500 J/kg and lapse rates of 6.5+ C/km to maybe support an isolated stronger elevated storm capable of hail. Any activity that may develop should then linger into Sat morning. Southeasterly sfc winds and increasing DPTS will make for milder overnight lows in the mid 60s inn the northeast, to the lower 70s southwest. Saturday...The warm front will try to retreat through the CWA, with enhancing EML behind it. Will carry low CHC POPs for most of the day for the chance for an isolated storm developing either sfc based near the front or elevated again anywhere. Of course if something would be able to get sfc rooted, there would be a severe threat. Locally heavy rain also a factor. With high temps in the lower 90s and sfc DPTs pooling in the low to mid 70s, heat index values of 100 to 103+ degrees are being fcst now in the southwest third of the DVN CWA Sat afternoon into early evening, and have issued a Heat Advisory for those areas. A quicker sfc front retreat may warrant a further north expansion of the headline if the next shift or two deems it worthy. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 251 PM CDT Fri Jul 12 2024 Saturday Night...Broad west-northwesterlies acrs the upper Midwest and an embedded short wave or MCV feature will look to ignite a heat dome-riding MCS acrs the eastern Dakotas, MN or into WI. Thermal thicknesses or gradient profiles such as H85 MB 18-21C angle from SD to northern IL/southern LK MI which could be the track of any mature or organizing MCS into Sunday morning. It could just miss our CWA to the northeast, but LLJ feed may allow it to back build into the northeast and eastern fcst area by Sunday morning. Damaging winds and heavy rainfall would be a threat from any mature piece of this complex making down into the area, if it can battle a probable EML and get sfc rooted with a cold pool. Besides this potential, there may be sctrd secondary elevated showers/storms further to the south acrs IA into IL feeding on southwesterly 20-30 KT LLJ feed. Will continue to massage POPs to account for all this. Overnight lows holding up in the 70s. Sunday...As long as convective debris or storm outflow boundaries don`t interfere, this day still shaping up to be a mid 90s ambient temps with sfc DPTs in the low to mid 70s making for Heat index readings in the 100-15+ range and the eventual need of a heat advisory. Latest medium range model/ensemble trends now adjust the more ideal storm track thermal ribbon to the north with EML capping to the south acrs our area Sunday night. Thus we could be largely dry with the flattened flow to the north and in-between short waves, as opposed to another late night/nocturnal MCS. Monday and Tuesday...Monday looking like another heat advisory day especially if we have a lack of local convective activity out of Sunday night. Some signs of a more vigorous short wave and steering flow buckle from the north that may allow a better chance for either storms to move in from the northwest late Monday afternoon and night, or possible develop over head. In either case enough buoyant energy to fuel strong to severe storms and heavy rain if they do indeed manage to make into the fcst area. This buckling or amplifying northwest flow to be the start of an air mass regime change that sweeps a significant cool front down through the region from the north on Tuesday, which may fire more storms along this FROPA process on Tuesday. High temps a challenge this day depending on FROPA timing, cloud cover and precip chances. Wednesday and Thursday...With the cold frontal passage looking to occur now on Tuesday, while storms re-fire along to southward pushing boundary to the south of the area, we may be under the influence of cooling northerly flow now on Wednesday. Still some chance of over-running showers in the south, and maybe afternoon instability isolated shower development further to the north under lingering cyclonic flow aloft. But overall this will be the beginning of a cooler, dry and less humid weather regime as Canadian high pressure is allowed to dump down the upper to mid MS RVR Valley and western GRT LKS. High temps in the 70s to low 80s with scoured out humidity(besides corn evapo-transpiration input) look on tap for the late week period. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1230 AM CDT Sat Jul 13 2024 Scattered to spotty broken VFR ceilings will continue through the morning, and some of these clouds might develop into isolated showers and storms (20% coverage). But confidence on this remains low, especially given minimal coverage, so do not have in any of the TAFs. For the afternoon, it`s also another case of if anything develops it would be low coverage, and looks to be mainly DBQ issue if there are any storms. South winds will have occasional gusts in the 16-20 kt range this afternoon. Storms are becoming more probable over the Minnesota/Wisconsin border region later this afternoon. The more organized these storms are, the greater likelihood they will move south- southeast and affect some of the TAF sites this evening, including the possibility of gusts exceeding 35 kt. At this time, confidence of TSRA is only to the level of a PROB30 inclusion. && .HYDROLOGY... Issued at 1043 AM CDT Fri Jul 12 2024 The crest on the Mississippi River is between New Boston, IL (L/D 17) and Keithsburg, IL. Areas upstream of New Boston through the Quad Cities are coming off a a broad crest. From Keithsburg, IL downstream to Gregory Landing, MO a broad crest will commence over the next 0.5 to 1.5 days. Tributary Rivers: On the lower Cedar River near Conesville, IA, minor flooding continues as water levels continue to fall. The lower Wapsipinicon River near Dewitt, IA will remain in moderate flood through Saturday. A fairly rapid drop in water levels will commence Saturday night as backwater effects from the Mississippi River decrease. Minor flooding continues on the lower Iowa River at Oakville due to backwater effects from the Mississippi. Once the broad crest on the Mississippi gets downstream of Keithsburg, IL, water levels on the lower Iowa River will slowly begin to fall. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for IAZ076>078-087>089-098-099. IL...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for ILZ025-026-034-035. MO...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for MOZ009-010. && $$ SHORT TERM...12 LONG TERM...12 AVIATION...Friedlein HYDROLOGY...08