936 FXUS63 KFSD 272043 AFDFSD AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 343 PM CDT Thu Jun 27 2019 .SHORT TERM...(This Evening through Friday) Issued at 338 PM CDT Thu Jun 27 2019 The convection from this morning that brought heavy rain and severe weather to the area has finally pushed east, although has left areas east of I-29 littered with a couple outflow boundaries and convergence zones. Further to the west, faster clearing has resulted in temperatures rising into the mid to upper 80s with heat indices in the lower to mid 90s. For this evening and tonight, high res guidance has hinted at some additional festering of showers and storms east of I-29 although current satellite and radar trends are lacking evidence as of mid afternoon with the better chances looking to be east of our forecast area. Have included slight to low end chance POPs for this possibility. May also see clouds leak in from the north and east depending on the extent of this activity. Friday will begin the process of amplifying our heat into the weekend. With 850 mb temps running above the 90th percentile of climatology and 925 mb temps running in the mid to upper 20s C, would expect afternoon temperatures to rise into the upper 80s to lower 90s across our southwest half. Combine this with dewpoints in the lower 70s and would expect heat indices nearing 100 degrees and thus issued a Heat Advisory for this area. The Sioux Falls area may be somewhat marginal as far as criteria but given the urban interface, went ahead and included the greater metro. Further to the east in SW MN and portions of NW Iowa, potential cloud and convective contaminants, along with somewhat cooler mid level temps, will hold temperatures a few degrees cooler. .LONG TERM...(Friday Night through Thursday) Issued at 338 PM CDT Thu Jun 27 2019 Overnight lows Friday night into Saturday likely won't fall below 70 in most areas with dewpoints entrenched in the upper 60s to lower 70s. This will start the day Saturday off on a mild note and set the stage for the peak of our expected heat. Continued warm 850 and 925 mb temperatures will allow for widespread 90s across the region and heat indices near or above 100 in most locations. This will likely result in the necessity of further heat headlines which will be addressed on future shifts. With the upper level ridge axis overhead, precipitation chances for Saturday look pretty non- existent. Upper level ridge and surface boundary begin to collapse southward by Sunday and while most of our area will see another very warm day, our far northwest zones near Huron will begin to see temperatures retreat slightly. As this boundary continues to sag south into Sunday night, most models key in on another round of showers and thunderstorms. Instability values are again relatively healthy (at least initially) but overall deep layer shear lacking. Pattern early to mid next week becomes much more uncertain with the GFS suggesting mid and upper level troughing while the ECMWF/Canadian suggest a continuation of a broad upper level ridge. For this reason, along with the earlier active weather across our area, didn't make any changes to the populated blended guidance. Overall, looks like cooler temperatures back into the 80s and occasional precipitation chances. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 1209 PM CDT Thu Jun 27 2019 Immediate concern is for the few remaining thunderstorms moving thru NW Iowa late this morning/early this afternoon and the occasional MVFR ceilings associated with this activity. Latest hi-res guidance suggest some activity may continue to fester east of I-29 late this afternoon and into this evening, although fairly good consensus that this would be well east of the terminals and thus no mention was included in the TAFs. Late tonight and early Friday, lower stratus in the MVFR to IFR range may build in with highest confidence at KHON. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...Heat Advisory from 2 PM to 8 PM CDT Friday for SDZ050-052-053- 057>071. MN...NONE. IA...Heat Advisory from 2 PM to 8 PM CDT Friday for IAZ012-020-031. NE...Heat Advisory from 2 PM to 8 PM CDT Friday for NEZ013-014. && $$ SHORT TERM...Kalin LONG TERM...Kalin AVIATION...Kalin