Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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843 FXUS63 KDMX 062331 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 631 PM CDT Thu Jun 6 2024 ...Updated for the 00z Aviation Discussion... .KEY MESSAGES... - Wind Advisory in effect for the rest of this afternoon. Gusts up to 50 mph possible along with localized areas of blowing dust along roadways, leading to reduced visibilities. - Marginal risk for severe weather for storms arriving Friday night. Hail and wind the primary threats. Heavy rain possible and looks to be placed just south of the state, at this time. - Periodic chances for precipitation under seasonal high temperatures for much of next week. Hotter temperatures arrive by the end of next week. && .DISCUSSION... Issued at 230 PM CDT Thu Jun 6 2024 Northwest flow continues today with an area of high pressure moving in from the northwest. As this deepens across Nebraska today, the pressure gradient will increase. The upper level low center will sag into the Great Lakes region and increase winds aloft as well with 850 and 700mb winds valued between 35 and 40kts can be found especially across the north this afternoon. Winds at these levels are not as pronounced compared to the 50kt+ winds found this morning, but sustained Wind Advisory winds can still be found across the north this afternoon due to efficient mixing in the dry PBL. Gusts exceeding 50mph have been recorded. Channels of blowing dust have formed across some roadways, with reduced visibilities causing disruptions to traffic. Caution should be used if entering one of these areas of blowing dust. With the influence of the upper level low, some cumulus clouds can be found in the northeast, but with high enough clouds bases, not expecting any rainfall out of these clouds. Beneath the persistent upper-level northwest flow, some ridging will nudge southwesterly winds into the state by midday. Pacific moisture will be carried with an incoming shortwave. An H85 trough will build in the Plains Friday evening and contain the low level jet in Kansas, veering into Missouri overnight. Consequently, low level moisture will build in the southwest. There, MUCAPE values will near 1000 J/kg with 50kts of deep layer shear. An overnight thunderstorm complex will move along that instability gradient, sagging southeastward as the jet noses into Missouri. Expecting storms to be elevated in nature with wind and hail the main convective threats. The progressive nature of the storms will spare southwest Iowa from training storms in an otherwise primed heavy rain environment. PWATs will near 2 inches with warm cloud depths over 10kft. CAPE profiles are elongated and skinny, favorable for droplet collision and coalescence processes. The HREF PMM QPF has rainfall amounts locally up to 3 inches in the main swath of the WAA wing. Right now, the heaviest rain looks to be displaced to the south of the state with values in southwest Iowa remaining generally under an inch, but trends will continue to be monitored. Rain will fill in the north late Friday night in association with a passing shortwave with some reinvigoration of showers along the trailing front during the daytime Saturday, prolonging precipitation chances, albeit appearing light at this time. Some uncertainty remains in Sunday`s weather as 12z deterministic guidance differs in how it handles the evolution of a shortwave diving down from Canada and into the Northern Plains. It should be noted that the 12z GFS solution appears to be an outlier, at this time. Until the broad upper level troughing departs, temperatures will remain in the low 80s next week. An eventual warmup into the 90s will come once the ridge is allowed to build in. Similarly, while under the influence of northwest flow, periodic rain chances will linger into next week. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 631 PM CDT Thu Jun 6 2024 VFR conditions will persist through the period. Gusty northwest winds have started to ease and will continue to diminish by 02z this evening. The forecast remains quiet through the rest of the period with thunderstorm chances returning late Friday afternoon and evening. These will be addressed in future updates. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Jimenez AVIATION...Hagenhoff