509 FXUS63 KIND 211631 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 1131 AM EST Mon Jan 21 2019 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 358 AM EST Mon Jan 21 2019 Arctic high pressure will push across the region today and begin to move east of the area tonight, providing continued cold conditions and dry weather through tonight and into early Tuesday. An approaching low pressure system will move through the Great Lakes Tuesday afternoon into Wednesday, providing another opportunity for widespread precipitation, some of which may fall as freezing rain Tuesday afternoon and evening, before transitioning to all rain, and then back to snow as colder air moves back into the area late Tuesday night and Wednesday. Additional waves in the overall cyclonic flow aloft will bring periodic light snow chances from Thursday night onward as we drop back into the deep freeze. && .NEAR TERM /Rest of Today/... Issued at 1003 AM EST Mon Jan 21 2019 This morning's upper air suggests the current highs for today may be too cool. Will nudge up the highs a category on the update. Wind chill values continue to rise above criteria as temperatures warm. Planning on riding the wind chill headlines until expiration at 211700Z. Previous discussion follows. Quite cold this morning with temperatures as low as -2 and most all of the area well into the single digits under mostly clear skies. Expect a mostly clear day until late, with upper level cloud increasing ahead of the next system. Wind chill values have thus far generally remained above strict criteria, but still quite cold. Will keep the wind chill advisory going. Consensus temperatures were generally reasonable, if perhaps a bit too warm in spots, but only minor adjustments were necessary. && .SHORT TERM /Tonight through Wednesday Night/... Issued at 358 AM EST Mon Jan 21 2019 The main focus for the short term will be on the low pressure system moving through the Great Lakes Tuesday and Wednesday. Precipitation will likely hold off until Tuesday afternoon and become more widespread as time goes on Tuesday into Wednesday night. Precipitation will likely begin as snow across the far northern area, with a transition zone of wintry mix. Of significant concern is the fact that by the time precipitation begins across central Indiana, roads and other surfaces across the area will have been sitting at less than 20 degrees for the better part of 3 days. Even with some sunshine today, strongly suspect that road surface temperatures will lag above freezing air temperatures by several degrees and hours, and impactful freezing rain may occur far longer than forecast builder produces it. Have added some admittedly hand waving road temperature grids to account for this and hold onto the freezing rain threat into Tuesday evening. As colder air begins to move back into the area late Tuesday night into Wednesday, expect any lingering precipitation to change over to snow on the back side of the precip band. Do not, however, expect any significant accumulation. && .LONG TERM /Thursday through Sunday/... Issued at 254 AM EST Mon Jan 21 2019 Cold weather with a series of upper level weather disturbances will bring snow chances from time to time this period. ECMWF shows a highly amplified upper pattern in place during this time with strong ridging in place across the Western United States and a deep and broad trough east of the Rocky Mountains. This will result in NW flow for Indiana and the Ohio Valley and plenty of cold Canadian air spilling into our region and providing below normal tempertures. A few clipper like short wave are suggested to push across Indian within the flow during the period...The first and Thursday Night and Friday morning...the second on Saturday...and a third is suggested on Monday. All of these system will have little moisture to work with as for the most part the gulf remains closed. However with the strong dynamics aloft...light snow cannot be ruled out with small to minimal accumulations for now. Given the NW cold flow...trended temps at or below the forecast builder blends...particularly in the wake of passing clippers. && .AVIATION /Discussion for the 211800Z TAFS/... Issued at 1130 AM EST Mon Jan 21 2019 Scattered to broken layers above 050 expected at the terminals through late evening. Unrestricted visibility. Surface winds 090-120 degrees at 6-10 kts this afternoon will gradually veer a bit to 120-140 degrees by late evening. Occasional surface gusts around 18 kts possible by late evening as well. && .IND WATCHES/WARNINGS/ADVISORIES... Wind Chill Advisory until noon EST today for INZ021-028>031- 035>049-054>057-064-065. && $$ SYNOPSIS...Nield NEAR TERM...Nield/JAS SHORT TERM...Nield LONG TERM...Puma AVIATION...JAS