Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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508 FXUS63 KOAX 011743 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1243 PM CDT Sat Jun 1 2024 .KEY MESSAGES... - Daily storm chances starting by this evening and lasting through at least Tuesday. - The highest chances for strong to severe storms are on Sunday and Tuesday, but confidence is low on exact timing and how widespread the severe weather threat will be. - Slightly warmer through next week with highs in the upper 70s and 80s. && .DISCUSSION... Issued at 311 AM CDT Sat Jun 1 2024 Pretty quiet early this morning with radar showing only some light lingering returns in our area following our day of heavy rain. To our west, a few storms were going up over in the NE panhandle on the nose of some weak low level moisture transport. CAMs suggest they will push east through the morning and gradually weaken, though a few pieces of guidance suggest they could make it to portions of northeast NE by late morning through mid-afternoon. Shouldn`t amount to much more than a brief downpour and some lightning if they make it (probably a 10-15% chance). Additional storms are expected to approach from the west late this evening into early Sunday, but once again should weaken as they push east, with most guidance in good agreement that instability quickly tapers off in our forecast area. That said, it is worth noting that a few pieces of guidance (various GEFS/EPS members and the 01.00Z NAM) give us a little more instability and suggest the storms organize into an MCS and push through Sunday morning on the nose of strong moisture transport. Then during the day Sunday, the general idea is that we`ll see strengthening southerly flow/moisture ahead of a surface low in eastern CO and some shortwave energy progged to move along the NE/SD border. This looks to usher in a warm, moist, unstable airmass with MUCAPE values of 2000-3000 J/kg ahead of a cold front approaching from the northwest, suggesting we`ll see a line of strong to severe storms late Sunday afternoon/evening. However, there`s quite a bit of spread on just how much shower and storm activity we`ll see during the day, likely in large part owing to differences in cap strength. This will play a large role in how the evening severe weather threat plays out, with any daytime storms likely greatly reducing instability ahead of the approaching front. In fact, if storms do get going during the daytime hours, a few could be strong to severe, though deep layer shear does look to be on the weak side (25-30 kts), suggesting they could be a little disorganized. So bottom line, we`re highly confident we`ll see thunderstorms at some point on Sunday (70-90% chance), but lots of questions remain on exact timing and the overall severe weather threat. Less storms during the day would mean a much stronger line of storms for the evening. More storms during the day would mean a more prolonged strong to severe storm threat, but maybe a little lower end when it comes to coverage and strength of severe storms. Flooding is probably the severe weather threat we have the highest confidence in seeing simply due to the recent heavy rainfall and additional rounds of storms in an environment with precipitable water values progged to be hovering around 1.50 inches. Additional storms would be possible Monday with a decent amount of instability remaining in place over at least the southern half of the area and some moisture transport continuing to point into the region. Tuesday looks to be our next best chance for severe weather, with a very similar setup to that of Sunday as we could see some daytime showers and storms ahead of an approaching cold front that could bring another line of strong to severe storms Tuesday evening. Behind that front, model consensus is that surface high pressure builds in and keeps us mostly dry, though there are some hints that a few bits of weak shortwave energy slide through the northwesterly flow aloft and bring us additional shower and storm chances through the latter half of the work week. However, at this time those chances appear to be 10% or less. Otherwise, expect seasonable temperatures for the start of meteorological summer, with upper 70s to mid 80s on tap through next week (though daytime showers and storms could lead to cooler highs on a couple days). && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1238 PM CDT Sat Jun 1 2024 A shallow field of clouds continue to float across the terminals this afternoon just above and below FL030. Winds are currently out of the northwest at less than 10 kts, with the expectation that they begin swinging northeasterly this evening, then southeasterly by tomorrow morning. Short-term models have been all over the place when it comes to shower and storm chances, which are for now not in the TAFs. If storms do form, they`d affect KOMA, KOFK, and KLNK for about an hour overnight between 07-10z from west to east. A much better bet is for a strong line of storms to affect the area after 02z tomorrow night, with gusts over 50 kts being possible. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...CA AVIATION...Petersen