504 FXUS63 KABR 091649 AAA AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1049 AM CST Wed Dec 9 2020 .UPDATE... Issued at 1049 AM CST Wed Dec 9 2020 Another much above normal temperature afternoon is expected across the cwa. Surface high pressure over eastern sd building east today will make the winds turn to the south and southwest. Mid and high level clouds in northwest sd will be moving east across northern sd through the afternoon. This will affect temperatures some but overall mostly sunny skies will result in highs again in the 50s and lower 60s. UPDATE Issued at 522 AM CST Wed Dec 9 2020 See updated aviation discussion below. && .SHORT TERM...(Today through Thursday Afternoon) Issued at 314 AM CST Wed Dec 9 2020 Weak upper level ridging this morning will give way to a more zonal flow developing by this afternoon. This zonal flow will continue tonight and into the day Thursday as a shortwave trough slides from the Pacific NW to the northern Rockies. At the surface, high pressure will slide across the area this morning, with a trough digging down the lee of Rockies this afternoon. WAA develops ahead of this trough, with H925 temperatures in the +6C to +12C range this afternoon. This will give us another day of well above normal temperatures. The trough/cold front tracks across the area tonight, with cooler high pressure nosing in on Thursday. Temperatures on Thursday will still be above normal, but more like 10 to 15 degrees above normal instead of the 20 to 30 degrees above normal that we have been seeing and will see again today. No precipitation is expected today through Thursday. High temperatures today will range from the lower 50s east to the mid 60s southwest, with lows tonight in the upper 20s to lower 30s. Highs on Thursday will be in the upper 30s to lower 40s. .LONG TERM...(Thursday Evening through Tuesday) Issued at 314 AM CST Wed Dec 9 2020 Expect highs in the upper 20s and 30s, and lows most days in the teens to low 20s. We'll start at 00Z Friday with a surface high pressure across the western Dakotas, with low pressure across Lake Superior and northern TX, with a trough stretching in between. At 500mb there looks to be several waves embedded in a couple of larger troughs stretching from Hudson Bay through ND/MT, and the desert southwest. The northern stream trough will exit to our east Thursday night, with a ridge building in Friday afternoon through midday Saturday. For our area, the surface ridge looks to be the dominating feature. While the main area of high pressure slides from north central Canada into Ontario Friday night, it should keep a ridge across our area through at least Saturday. 850mb temperatures should remain in the -2 to -6C range through Sunday evening. It looks like the broader scale trough will take over much central U.S. by 00Z Sunday. The last couple operational runs of the GFS do show the potential for light snow Saturday night into Sunday morning over western SD. However, most solutions are dry. Have continued the trend of dry weather through the period. The forecast area will be clipped by a surface trough extending from a low crossing central Canada on Sunday, but the impact looks minimal with additional clouds and a northwesterly wind shift. Timing and location of the next broad surface low passage is a little in question Monday, but it still looks dry with high pressure settling back in again. && .AVIATION...(For the 12Z TAFS through 12Z Thursday Morning) Issued at 522 AM CST Wed Dec 9 2020 Terminals KABR,KATY,KPIR,KMBG VFR conditions will prevail across the area today and tonight. Northwest winds will increase into the 15 to 25 knot range after 06Z Thursday behind a cold front moving through the area. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Mohr SHORT TERM...Parkin LONG TERM...KF AVIATION...Parkin