Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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318 FXUS63 KDMX 282335 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 635 PM CDT Tue May 28 2024 ...Updated for the 00z Aviation Discussion... .KEY MESSAGES... - Outstanding day on Wednesday with light winds and no precipitation. - Confidence in widespread precipitation late Thursday through Friday night is declining and there is a slower trend. && .DISCUSSION... Issued at 249 PM CDT Tue May 28 2024 Another short wave is dropping southeast into northeast Iowa this afternoon. Scattered showers and a few weak thunderstorms have develop into southeast Minnesota and parts of northeast Iowa this afternoon in response the system. Another area of precipitation was just exiting far southern Iowa. No severe weather is anticipated and this afternoon though some gusty winds and perhaps very small hail could occur. The activity will shift out of the area by late this afternoon as the system moves out of the area and surface high pressure moves in from the west. The area of high pressure will settle over the state tonight and then move slowly east on Wednesday. Wednesday will be a nice day with mostly sunny to partly cloudy skies with some cumulus development. Light winds are also expected with mixed layer winds generally 8 kts or less and only weak pressure gradient at best. High temperatures will be in the low to mid 70s. The area of high pressure will move little Wednesday night through Thursday morning. The high will help keep the Gulf moisture blocked to the south and southwest during this period. The upper ridge will begin to advance east on Thursday as a strong system moves east through Montana and the Dakotas and in turn will aid pushing the high eastward. This will allow the Gulf moisture to return north into the Nebraska and the central Dakotas by Thursday morning. The area of high pressure should keep much of the forecast area dry through the afternoon Thursday. Still maintaining some chances west of Interstate 35 for the afternoon but expect later trends that will hold off precipitation chances until Thursday night to prevail. Weak mid-level lapse rates over Iowa and the moisture transport and instability along the Missouri River and westward all point to these later trends. Thursday night, another high pressure moves east from Wyoming and Montana and will congeal into high pressure ridging to the larger high to the east. This will again shield move moisture transport to the south. Therefore, confidence in precipitation from late Thursday through Friday night is not the highest and some of the latest deterministics are jumping on this drier trend for this period. For Saturday night into early next week, the upper flow becomes more zonal with a few short wave moving through later Sunday into Monday but again confidence on widespread activity is still not there let alone confidence in severe potential. Temperatures will warm through the period with a return to widespread 80s Saturday into early next week. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 635 PM CDT Tue May 28 2024 A few showers are near ALO at the start of the period, but look not to impact the site remaining just east of the terminal so have favored VCSH for the first two hours. Thereafter, a period of dry weather is forecast with VFR conditions prevailing. FEW to SCT cumulus development with bases above FL035 is expected by late morning and early afternoon over eastern into central Iowa before dissipating around sunset. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Donavon AVIATION...Ansorge