Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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324 FXUS63 KDVN 281729 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 1229 PM CDT Sun Apr 28 2024 .KEY MESSAGES... - Chance for strong to severe storms this afternoon/evening. Slight Risk, level 2 of 5, remains for areas along/south of Highway 34. - Active forecast remains through the long term, with near daily chances for precipitation after Monday. - Temperatures will remain above normal through midweek, trending towards normal for the end of the week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 251 AM CDT Sun Apr 28 2024 Deep upper wave continues to slowly push northeast through the central United States, becoming negatively tilted through the day. Surface low associated with the system will start to slowly traverse northeast through Sunday. Stationary boundary that has been draped over northern portions of our CWA will remain in place through much of the day, as the surface cold front grows stronger and pushes through our area. This cold front will be the feature to watch, as it will bring the necessary surface forcing to see showers and storms through the day, especially in the afternoon/evening. Ahead of the cold front is a favorable environment for some strong to severe storms. Although, confidence remains low. In either case, we will still see a line of showers and storms push through the area late in the afternoon and evening. These will also bring a brief period of heavy rainfall, but the flash flood threat remains low for the area tomorrow. Instability will be low-moderate in area, with the shear being the main driver for storm organization and severity. The extent to which we see showers/storms through the day will either decrease or increase chances for severe weather. Guidance is favoring showers and storms through much of the day, which would limit the severe potential. The main thing that would help get severe storms in this scenario would be the overall forcing produced by this dynamic storm system. Thus, we will not rule out the chance for severe. If we do see severe storms, the primary threats will be severe winds and hail, with tornadoes being the secondary threat. Confidence remains low on the severe threat tomorrow, but it will be something that we will continue to message the potential for. Thus, remain weather ready tomorrow. The SPC has areas along/south of Highway 34 in a Slight (level 2 of 5) Risk for severe weather, with a Marginal (level 1 of 5) for the remainder of the area. It is important to note that there has been a southerly trend in the severe threat, especially in the last 24 hours. Tonight... After the line of convection moves through tomorrow evening, much of the area should remain dry and breezy after midnight. Given some bouts of energy continuing to hit our area after the main wave, I wouldn`t be shocked to see a few showers after the main line of convection passes. Some guidance is hinting at this, but confidence is low. This will be the end of the severe threat for Sunday though, with temperatures dropping into low 50s to near 60. && .LONG TERM /MONDAY THROUGH SATURDAY/... Issued at 251 AM CDT Sun Apr 28 2024 Looking at the whole long term, it would seem that Monday has the best chance to be the only dry day of the week. The pattern goes zonal briefly after the system passes on Sunday, but this will be short-lived. A few disturbances are forecast to pass through the flow midweek, with the potential for a more potent wave to impact the area Friday/Saturday. Much of the week, above average temperatures will be seen, with most in the mid-upper 70s. Towards the end of the week, temperatures moderate near normal, as we will be socked in clouds and rain showers. Tuesday, an upper wave will pass through the area, with a relatively strong vort max passing through late in the day. Guidance is in general agreement on seeing showers/storms with frontal passage that evening/night, but there are some differences with moisture content. Timing is generally captured well amongst guidance, with them also indicating that this will move through quickly. Confidence is low on severe potential, but will continue to monitor as more short term guidance comes in. After that system, we will start to see a potent wave deepen over the Rockies mid-late week. We will see a few leading impulses pass through the area, leading to occasional showers/storms for the remainder of the week. This will be a wet period, with the potential to see a bit of rain. While it is too soon to figure out the flash flood potential, it is safe to say that we can expect some rises along area rivers if we see this persistent rain. The parent wave developing is the one that has our attention though. There is plenty of uncertainty with this, as well as major timing differences amongst guidance. Although, all long term guidance shows this system. If this wave deepens enough and we get that negative tilt upon arrival, we may see the potential for strong to severe storms late in the week. Although, it is too soon to say for sure. So, just be mindful and stay up to date on our forecasts! && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1212 PM CDT Sun Apr 28 2024 Variable conditions will be seen throughout the TAF period with low pressure passing to the west of the area and moist air in tow. Look for mainly MVFR conditions over the next 24 hours, with lower visibilities and ceilings to IFR possible in rain showers. An isolated thunderstorm will also be possible. Late in the period, a return to VFR conditions is possible mainly at KMLI/KBRL. Winds will prevail from the south initially with gusts around 20-25 kts at times, before veering to the west late in the period. && .HYDROLOGY... Issued at 1124 AM CDT Sun Apr 28 2024 Several tributary rivers are now over flood stage in our southern portions of the CWA due to last night`s 1-2 inch rainfall on top of moist soil conditions and already elevated river stages. Other rivers will see significant in-bank rises to action stage, to the north of this rainfall swath. The rates of rainfall last night were initially very heavy, but the QPF was split from this heavy first 1" to a more conservative 0.20/ hr rate that fell the rest of the night. Thus, the rises may be more steady, rather than sharply felt this morning following the first few hours of rapid rises observed early today. La Moine River near Colmar... This river is above flood stage, and rising steadily today. Forecast rises to the upper end of moderate flooding is forecast by the RFC...and that could have a chance on exceeding the Major flood threshold of 24 feet Wednesday. This forecast is the one to watch most closely over the next 24 hours. Fox River near Wayland... The Fox saw the heaviest QPF upstream, but already seems be slowing it`s rise, near 16ft. A forecast of moderate flooding is in place cresting near 19ft late tonight/early Monday. The Pecatonica at Freeport and Rock River from Moline through Joslin... Rise to action stage are forecast by the end of the work week. Skunk River at Augusta... Another site that saw very heavy qpf fall in this basin, over 2 inches in some cases. The stage is rising rapidly this morning, a bit faster than modeled. Though it will be watched carefully, it appears likely to top out shy of flood stage Wednesday. This is the 2nd most needed to be watched carefully through tomorrow, and could potentially lead to a minor flood warning. Heavy rains remain possible later this week again as forecast by WPC. The timing of this rain would fall just past the crest on most active tributary rivers, and near the crest or just prior on the Rock River. Keep a general awareness of rivers in the week ahead, as this wet pattern continues to evolve. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Gunkel LONG TERM...Gunkel/Speck AVIATION...Speck HYDROLOGY...Ervin