Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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935 FXUS63 KOAX 190341 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1041 PM CDT Thu Jul 18 2024 .KEY MESSAGES... - An extended stretch of cooler-than-average temperatures will persist into next week. - Next widespread rain chances will be Friday evening into Saturday. There are additional spotty rain chances into next week. && .DISCUSSION... Issued at 302 PM CDT Thu Jul 18 2024 .Late this afternoon through tonight: Surface high pressure over central IA is contributing to mild weather (by July standards) across the region today with temperatures in the upper 70s to lower 80s as of 2 PM. The high will shift east tonight in response to a deepening low pressure system over southeast MT into western SD. Low/mid-level warm advection developing downstream from the low across central SD into north-central NE may support isolated to widely scattered showers and thunderstorms, a few of which could reach portions of northeast NE toward daybreak Friday. .Friday and Friday night: A shortwave trough located over southern Alberta and northern MT as of early afternoon is forecast to track from eastern MT Friday morning into the mid MO Valley by late Friday night, in tandem with the above-mentioned surface low. Increasing moisture and forcing for ascent ahead that system will support a general increase in showers and thunderstorms during the afternoon across central/eastern SD into northern NE with that activity spreading southeast through our area Friday night. While mid-level lapse rates are not expected to be particularly steep, the increasing moisture and strengthening mid/upper-level winds may yield sufficient amounts of instability and vertical shear for a few strong to potentially severe storms during the late afternoon and evening hours, mainly across northeast NE. Hail up to quarter size and/or wind gusts up to 60 mph are the primary hazards, along with locally heavy rainfall. Highs on Friday will be in the low to mid 80s. .This weekend: The 12z global models suggest that a high-latitude omega blocking pattern will become established, which will effectively maintain mid-level troughing across the mid MO Valley into early next week. As such, we will see continued shower and thunderstorm chances with the highest PoPs (50-70%) on Saturday morning. Areas of rain and associated cloud cover will result in seasonably cool conditions with daytime highs in the 70s. Another item of note is the potential for smoke from Canadian wildfires to filter into the region. Model forecasts suggest this would be mainly aloft, so it`s currently not expected to be an impactful occurrence to sensitive groups. .Next week: As mentioned above, the large-scale blocking pattern will maintain mid-level troughing across the region early in the week with periodic 20-30% PoPs on Monday and Tuesday. It does appear that we will see gradually warming temperatures with highs in the 70s on Monday warming back into the low to mid 80s by mid-week. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1041 PM CDT Thu Jul 18 2024 Main forecast concern will be timing and location of thunderstorms Friday. Guidance is in decent agreement we see some develop in northeast Nebraska from 11-15Z, but is split on how far southeast those persist. Most likely scenario is that only OFK sees storms, but if they hold together OMA and LNK could see something toward 18Z. Then a more widespread line of storms looks to move through Friday evening, though there remains large spread on timing ranging from 23Z to after 04Z at OFK. Once again, questions remain on how far southeast they`ll make it, but expect them to at least weaken quite a bit prior to reaching OMA and LNK. Outside of storms, expect VFR conditions with FEW to SCT clouds around 4000 to 7000 ft and southeast to south winds around 10 kts, with a few gusts near 20 kts at OFK. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Mead AVIATION...CA