Expires:No;;046030 FXUS63 KFSD 112301 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 601 PM CDT Sat May 11 2024 .KEY MESSAGES... - Some clouds will be present aloft this evening and night, but sufficient viewing conditions are still expected for seeing a potential Aurora tonight. - Low to moderate chance (10% to 40%) of showers and storms tomorrow afternoon and evening. Severe weather is not expected but some storms could produce gusty winds. - Temperatures will be closer to seasonal next week with the coldest highs focused around Wednesday. - Rain chances late Tuesday through Wednesday and potentially continuing through Thursday and Friday. Severe weather risks are low but additional meaningful rainfall is possible. && .DISCUSSION... Issued at 332 PM CDT Sat May 11 2024 Beautiful conditions persist across the area this afternoon, characterized by high temperatures in the 70s and marginally breezy winds. These conditions will continue for the rest of the afternoon hours so get out there and enjoy the nice weather! Remnant coronal mass ejections (CMEs) continue to make their presence known as they bring another chance to view the aurora tonight. Tonight's view is remains solid to view the potential Aurora but mid level warm air advection (WAA) may result in some mid level clouds. On top of the mid level clouds, literally, high level cirrus streaming in from the northwest may thicken a bit aloft as an incoming upper level wave pushes southwards through Canada to the international border. While this won't completely obscure the sky, it may make viewing the aurora a little bit more difficult. As of now, locations along the highway-14 corridor look to see the thickest cirrus aloft. Good news is that the cirrus will not last all night so there should be sufficient viewing potential during the overnight hours. A cold front tied to the previously mentioned upper level wave will reside in a surface pressure trough which will tighten the surface pressure gradient a bit. With a tighter gradient in place, slightly elevated southwesterly winds with gusts up to 10- 15 mph are expected tonight. The elevated winds will keep low temperatures a bit on the warm side only falling to the 50s overnight. The previously mentioned cold front will slide through the forecast area on Sunday, setting the stage for shower and storm development. 850 mb temperatures will warm to about +15 C aloft. Mixing this to the surface will result in high temperatures up to the 80s across the area. Dew points will only moisten to the mid 50s at the best as southwest flow ahead of the incoming front will not provide the best moisture return. With moist neutral mid level lapse rates in place, some instability will be generated, up to 1,000 J/kg of CAPE. With the best mid and upper level winds residing along the international border, little to no wind shear is expected. This will keep any severe storm potential at bay. Soundings do show a dry, inverted-v structure in the low levels so there could be some gusty winds with any storms that develop along the front. Light rain chances look to continue through the overnight hours across northwest Iowa. Low temperatures are expected to fall to the low 50s overnight. Low rain chances (<= 30% chance) hang across parts of northwest Iowa tomorrow as a vertically stacked low pressure system slowly exits the central plains. Light rain may wrap back around the low which would only produce minor rain accumulations. Otherwise, Monday will be a quiet day with breezy northeast winds with highs up to 70s and lows down to the 40s. Medium range guidance begins to vary in how the upper level pattern evolves through the middle of the week and end of the week. Tuesday will be a quiet day as large scale descent resides over the forecast area with highs again into the 70s. Ensembles are a bit more consistent on a trough moving into the Northern Plains on Wednesday. As of now, lapse rates look to be less then moist neutral so little instability looks to be present. This is further supported by the ensembles as they show only a 0-30% chance for CAPE values to exceed 500 J/kg. However, ensembles show higher probabilities up to a 30- 60% chance for exceeding a tenth of an inch of rain with this system. An active pattern looks to continue aloft which could result in more rain chance for the end of the week. Details remain uncertain at this time so have stuck with model blended PoPs for the end of the forecast period. Highs will remain in the 70s with lows falling to the low 50s. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 557 PM CDT Sat May 11 2024 VFR conditions will prevail through at least early Sunday afternoon. Mid level cumulus will dissipate later this evening. Light west winds will weaken overnight and turn southwest. A cold front slides in Sunday afternoon and evening, turning winds to northwesterly and bringing a low chance of scattered showers and storms. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...Meyers AVIATION...BP