Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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085 FXUS63 KDMX 221749 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA Issued by National Weather Service North Platte NE 1249 PM CDT Wed May 22 2024 ...Updated for the 18z Aviation Discussion... .KEY MESSAGES... - Gusty winds continue but steadily diminish through the morning hours. - Few light showers and sprinkles possible today, with the potential for some brief gusty winds with any healthier updrafts. - Additional thunderstorm chances late Thursday into Friday morning, then again on Sunday. && .DISCUSSION... Issued at 340 AM CDT Wed May 22 2024 >> Breezy Winds Continue This Morning After the events of the last few days, we get a much needed breather through the next two days, before more chances for thunderstorms arrive late Thursday night into Friday morning. Although conditions are currently dry across the state, gradient winds have been quite strong through the night and into early this morning. These are associated with the departing surface low pressure and the cold air advection funneling in behind it. Low stratus clouds have also been present through much of the night, which has helped to inhibit the development of a surface inversion and allowed wind gusts to linger through much of the night. Fortunately, as the low has continued northeast and cloud cover cleared, winds have started to diminish over southern and southeastern Iowa. Expect this downward trend to continue through the morning hours for more locations as the system departs. Winds may be breezy in northern Iowa again today, but not nearly to the extent of yesterdays gusts. >> Quieter Through Mid-Week As mentioned above, today and Thursday will provide a brief break from the active weather. However, a second PV anomaly passing through today may spoil our hopes of staying completely dry through Thursday. Most of the gulf moisture will be cut off from this wave, which will inhibit rain chances considerably. However, there have still been indications in high resolution guidance that a few isolated to potentially scattered showers may kick off as it passes through Today, primarily due to a lobe of mid to upper level moisture confined to the wave. This moisture aloft will still have to fight its way down to the surface, with forecast soundings indicating a dry vertical profile with a nearly 10-15F T/Td spread at the surface this afternoon. That all being said, the final nudger to include some low end precipitation chances in the forecast came down to the presence of roughly 500 to 1000 J/kg of CAPE in the afternoon. If realized, this would certainly aid parcels in overcoming the dry air near the surface. Likewise, if a convective shower or storm were to develop and rain into the dry air below it, brief wind gusts could develop. Of course, thats all dependent on IF anything can be lifted enough to take advantage of the instability and then also find enough moisture to precipitate. Therefore, would expect isolated showers at best, with sprinkles and virga being the more likely outcome across the area. >> More Shower and Storm Chances This Weekend Conditions look dry through most of the day Thursday, but another upper level wave will begin to influence the area as early as Thursday night and last into Friday morning. While this system doesnt look to be anywhere near as loaded as yesterdays, there will still be modest amounts of instability and shear as it passes through. A few stronger storms will be possible, but the timing of the system passage will help to mitigate our severe risks some. These do still have the potential to produce some efficient rainfall, with 1.5+ PWATs and persistent moisture transport near the surface and aloft. While there will be time for rivers to recover through the week after the recent rainfall, this could slightly delay the receding river levels for a few sites. However, not anticipating this to induce any flooding issues at this time, especially with the progressive nature of the storms, just something to keep an eye on as we get into the high resolution window. Shortly after the late Thursday into Friday system, another low pressure system lifts out of the southwest US on Sunday bringing more rainfall chances to the state. Any severe risk looks to stay south of us at this time, but will continue to evaluate this system as it draws closer in the coming days. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 1115 AM CDT Wed May 22 2024 VFR conditions are expected to prevail the next 24 hrs across IA. A few fair weather cumulus clouds will be around this afternoon, with some increase in mid and high level cloudiness tonight. Winds will be gusty from the west this afternoon. Winds will decrease and become light south tonight. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Dodson AVIATION...Taylor