Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
741 FXUS63 KOAX 072307 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 607 PM CDT Tue May 7 2024 .KEY MESSAGES... - Marginal risk of severe thunderstorms Wednesday afternoon and evening in northeast Nebraska and western Iowa - Light showers and a few rumbles of thunder linger through the Thursday, with drier conditions and highs in the 70s returning for a weekend conducive to being outdoors. && .DISCUSSION... Issued at 400 PM CDT Tue May 7 2024 Pleasant weather has developed over the area this afternoon with 15-25 mph southwesterly winds and current temperatures ranging from the low to mid-70s. A drier airmass has lead to slipping dewpoints, too, making the afternoon all the more comfortable under sunny skies. Weak convection has produced some 20 dBz radar returns over northeast Nebraska thanks in part to diurnal heating and a vort max embedded in the westerly flow rounding the upper low at 500 hPa. Isolated PoPs are warranted through the daylight hours. The low, mostly stacked to the surface, will split in two over the next 24 hours, with a piece ejecting quickly east over the Great Lakes and a low remaining behind, sinking slowly south over the Northern Plains. A weak shortwave at 850 hPa will bring a chance of showers / thunder tonight for areas along and south of Interstate 80 from about 10p to sunrise. Little to no QPF is expected with dry low levels in place. .WEDNESDAY and THURSDAY... Troughing remains but becomes oriented east to west in a Rex block type pattern. With the trof axis stretched across the northern half of the CWA, thunderstorm chances will remain with chance POPs. Lapse rates will skyrocket as the surface heats and temps slip at mid-levels. CAPE may sneak up the Missouri River Valley and peak near 1000 J/kg and enough bulk shear for a slight chance of strong to severe thunderstorms in the afternoon. Best chances will be north of a line from Red Oak, IA to Columbus, NE. Pattern recognition suggests weak funnels are possible. Thursday`s pattern remains mostly unchanged and diurnally driven POPs of 20% (east) to 45% (west) push south with the trof axis. CAPE will be diminished when compared to Wednesday. Temps will slip 5-15 degrees with CAA and will fall shy of mid-May averages. .FRIDAY AND THE WEEKEND.... Still expecting a shortwave to dive south through Iowa on Friday, but its rain looks more likely to fall east of this CWA. Have removed isolated chances of precip. Sunny skies should drive temps back into the 70s. Temps climb in response to increasing heights and the West Coast ridging prodding the trofing east. Ample high-angle sunshine helps push temps past the 80 mark on Sunday and the zonal flow suggests persistence is the right move for early next week, too. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 602 PM CDT Tue May 7 2024 Scattered showers with a few embedded rumbles of thunder will continue to drift across eastern Nebraska and southwest Iowa. Due to dry air near the surface, a few of these showers could produce occasional winds gusts as high as 40 to 50 mph this evening. Otherwise, expect showers to diminish in coverage after sunset, with winds subsiding to under 12 kts, out of the south. Another round of showers could move into southeast Nebraska around midnight tonight and spread northeast, however confidence in the coverage and timing of these showers remains low at this time. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Nicolaisen AVIATION...KG