Sunrise 6:27 AM   Sunset 8:19 PM Moonrise 8:31 PM   Moonset 5:38 AM

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FXUS63 KFSD 241956 AFDFSD

Area Forecast Discussion National Weather Service Sioux Falls SD 256 PM CDT Wed Apr 24 2024

KEY MESSAGES

- Chances for rain and storms return Thursday and persist through the weekend. Strong to severe storms are possible on Friday.

- Beneficial rainfall is possible Thursday night, with a 50-80% chance for exceeding a half an inch of rain.



DISCUSSION
Issued at 255 PM CDT Wed Apr 24 2024

CURRENT/TONIGHT: Quiet conditions continue to prevail across the region, with latest observation showing fairly light S/SE winds and temperatures in the upper 50s to mid 60s. Heading into evening, expect winds to primarily be out of the southeast, with gusts gradually increasing to 20-25 MPH throughout the overnight period.
As such, expect lows remain on the milder side, as temperatures only fall into the upper 40s to lower 50s.

THURSDAY: Upper level low over the southwestern CONUS ejects northeastward Thursday, causing showers and storms to return to the forecast. Should see largely dry conditions persist through the afternoon as upper level ridging holds tight overhead. That being said, some CAMs do suggested that a few isolated showers may be possible after daybreak with the initial surge of WAA. Nonetheless, with soundings showing quite a bit of dry air still in the lower levels, think the better chances will occur during the late afternoon/evening. In regard to winds, expect a strengthening LLJ to result in breezy conditions across the region, with southeasterly gusts between 25 to 35 MPH possible through the evening. May even see a few location approach 40 MPH at times. Like today, have highs rising into the mid to upper 60s.

As alluded to in the previous discussion, will see an elevated warm front surge toward the region Thursday evening. This in combination with increased moisture and broad WAA could spark some elevated convection. While we are not currently outlook in SPC's Day 2 Severe Weather Risk, can't rule out the possibility of seeing some elevated hailers early Friday morning if all the ingredients come together.
The other aspect to Thursday night is that 850 mb moisture transport will increase due to the strong LLJ in place, which will set the stage for beneficial rainfall. Ensembles have slightly increased their probabilities, now up to a 50-80% chance for exceeding a half an inch of rain Thursday night.

FRIDAY THROUGH SUNDAY: Widespread showers and storms are expected heading into Friday as the as the aforementioned upper level low nudges closer to the region. As noted in SPC's Day 3 Outlook, portions of our area have been included in a Slight (Level 2 of 5)
and Marginal (Level 1 of 5) Risk for severe weather. That being said, this threat remains conditional on how far the sfc warm front can advance and if we can achieve enough diurnal destabilization to overcome any cooling from the morning's storms. IF the warm front is able to reach the MO River Valley by Friday evening, believe there would be enough instability (~1000 J/kg) and moisture in the place to see large hail, especially with steep mid-level lapse rates in place. Do think it's worth noting, that like our system last Tuesday, think there is also a non zero chance that funnels or isolated tornadoes would be possible if a stacked low develops, especially considering the low cloud tops in place. Again, this threat remains highly conditional - so will continue to monitor trends. Aside from storm chances, Friday will continue the trend of near seasonal high temperatures in the 60s and perhaps 70s, again depending on cloud cover. Dew points will moisten into the 50s which will make for the first humid day across the area this Spring.

Otherwise, look for showers and storms to continue heading into the weekend. Depending on how the upper level low tracks, may see a lull in activity late Friday night through Saturday morning, with wrap around showers still likely by Saturday afternoon. Model consistency begins to wane by Sunday as yet another wave near the Rockies ejects toward the region. That being said, most guidance generally agrees that showers will be possible for much of the day. Similar to Friday night, the chance of seeing severe storms will largely depend on the waves evolution and surface front location. High temperatures look to remain in the 50s and 60s.

MONDAY THROUGH WEDNESDAY: Dry conditions look to prevail heading into the new week as upper level flow turns quasi-zonal. Warmer temperatures also look par for the course, with highs forecast to rise into the 70s Tuesday and Wednesday!

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
Issued at 1159 AM CDT Wed Apr 24 2024

VFR conditions are forecast to prevail this TAF cycle. Should see south/southeasterly winds continue through the afternoon, with direction becoming more predominantly southeasterly after sunset. Will then see winds gradually strengthen through the overnight period with gusts between 20 to 25 MPH possible by daybreak. Winds strengthen even more Thursday, especially along and west of I-29, with gusts forecast to range between 25 to 35 MPH. Otherwise, expect scattered showers to develop by the end of the period, though confidence in any one location remains low at this time - thus, have opted to exclude mention for the time being.

FSD WATCHES/WARNINGS/ADVISORIES
SD...None.
MN...None.
IA...None.
NE...None.

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