768 FXUS63 KIND 250302 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 1002 PM EST Sun Jan 24 2021 .UPDATE... The NEAR TERM and AVIATION Sections have been updated below. && .SYNOPSIS... Issued at 404 PM EST Sun Jan 24 2021 The work week will start out with a messy system bringing rain to much of the area as well as freezing rain and snow at times for areas along and north of I-70. More rain and snow is in store for midweek before the work week ends in drier weather. This weekend will see another round of rain and possibly some snow. && .NEAR TERM /Overnight/... Issued at 1002 PM EST Sun Jan 24 2021 Mainly cloudy skies linger across the region this evening along with areas of fog focused over the southeast half of the forecast area. Temperatures have been generally steady for the last few hours...sitting in the low to mid 30s. Continue to monitor trends as the 00Z model suite trickles in along with continues updates to the CAMs. The evening update will focus predominantly on refreshing the forecast for the next several hours and delaying the onset of the precipitation by a few hours. Expect a largely quiet next several hours with fog remaining focused over the southeast half of the forecast area. Precip will approach from the southwest as the warm front moves east late tonight...generally holding off until after 10-11Z in the lower Wabash Valley and generally near to after daybreak elsewhere. There is a subtle increased potential in a wintry mix to begin at precip onset over far southern counties but any mixing should be confined to 1-2 hours at most before surface temps begin rising. No changes to winter headlines at this point but new guidance is upping the potential for icing a bit in coverage and duration Monday over the central portion of the forecast area. Will continue to closely monitor trends into the overnight. Zone and grid updates out. && .SHORT TERM /Monday through Tuesday Night/... Issued at 404 PM EST Sun Jan 24 2021 A more potent low pressure system will be impacting the area early Monday into Tuesday. A warm front will set up across the Ohio Valley, extending off the low tracking from the southern Plains to the Ohio Valley. Frontogenetical forcing will form along the front, over the area prompting heavier rainfall as warm moist air advects in from the south. Precip will start in the SW during the early morning hours, expanding to the north as the morning goes on. Temperatures in the SW should start off warm enough that precip should be all rain through the day. Freezing rain and snow will start to be a possibility from a line of Terre Haute to Bloomington to Seymour and northward. There is quite a bit of uncertainty on exactly when and what type of precip will fall for much of the area as the freezing line is will set up somewhere across the forecast area. Temperatures are trending slightly colder, which has led to a slight southern shift in the freezing rain impact as well as higher snowfall amounts in the more northern counties. This wintry mess is expected to impact the Monday morning commute, so despite the uncertainties, a winter weather advisory has been issued starting at 10z Monday morning. It will last until 18z for most of the forecast area, but for the northern tier of counties, the advisory will last until 02z Tuesday as the wintry mix will last longer up there. Along our southern border, thunder will be possible during the afternoon hours, where instability will be higher. As the low approaches, tighter pressure gradients will impact the area and gusts of up to 25 kts are possible for the afternoon to late evening hours. Pops continue for much of the area into Tuesday as moisture on the backside of the low lingers in the area, but mainly for the northern half of the forecast area. Freezing rain may again be a threat Monday night as temperatures drop some overnight. Precipitation is expected to fully exit Tuesday afternoon as the low continues to exit off to the east. && .LONG TERM /Wednesday through Sunday/... Issued at 220 PM EST Sun Jan 24 2021 The long term will start off dry Wednesday morning under the influence of an upper ridge, just off to the east. However, there is another chance of precipitation Wednesday afternoon and night as a sharp upper low moves across the Ohio Valley Wednesday evening. Deeper wraparound moisture, supplied by a strengthening surface system departing the East Coast supports the higher PoPs over our southeastern counties. Either way, blend PoPs currently are not higher than chance. However, with how deep the moisture is and good forcing, took the lead of ILX and raised PoPs to good chance bordering them Wednesday afternoon and also raised PoPs Wednesday evening bordering ILN and LMK. Northeast winds ahead of an upstream surface ridge, low level thermals, critical thicknesses and BUFKIT soundings support that either it will start off as snow across all of central Indiana Wednesday afternoon or start off briefly as a mix, including freezing rain or drizzle potential, and then changeover snow late in the day from northeast to southwest. The aforementioned ridge of high pressure will move across late in the week and provide subsidence and dry weather to central Indiana for the late week and the first part of the early weekend. After that, a southwestern system will bring Gulf moisture northeast across central Indiana as it gets closer Saturday. This would support increasing rain chances Saturday and Sunday. Temperatures will be trending up this weekend after the high pressure ridge moves to the east Friday with afternoon highs mostly seasonable in the 30s Wednesday, below normal in the 20s and 30s Thursday but above normal in the 40s by Saturday. && .AVIATION /Discussion for 250300Z TAF Update/... Issued at 1002 PM EST Sun Jan 24 2021 Minor changes for the evening update based on current obs. 00Z discussion follows. IMPACTS: Poor flying conditions will continue through Monday night. IFR and lower conditions are expected at times throughout the forecast period. Precipitation will begin near daybreak Monday and continue into Monday evening. Expect a wintry mix of freezing rain and snow at all but KBMG...gradually transitioning to rain by Monday afternoon in most areas. DISCUSSION: Low clouds were entrenched across central Indiana this evening and in some areas...fog was present as well. The low clouds will keep poor flying conditions across the region tonight even as precipitation is not expected to return until after 09-10Z with the approach of the low pressure from the southwest. Challenging precip type forecast for Monday as low level temperatures and the eventual placement of a warm front will dictate precip type and duration at each of the terminals. Other than some brief mixing near onset...KBMG should see primarily rain. Both KHUF and KIND will likely see a period of freezing rain and snow before eventually transitioning to primarily rain Monday afternoon. AT KLAF...mixed precipitation may continue into Monday evening. Winds will become gusty Monday afternoon with the passage of the low pressure through the region. Expect a predominant E/NE wind on Monday as the low tracks south of the terminals. CONFIDENCE: High confidence in poor flying conditions through Monday evening. High confidence in precipitation but low confidence in timing and duration of specific precip types at each terminals. && .IND WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 5 AM to 1 PM EST Monday for INZ035>037-039-043>049-051>057-062>065. Winter Weather Advisory from 5 AM to 9 PM EST Monday for INZ021- 028>031-038-040>042. && $$ SYNOPSIS...KH NEAR TERM...Ryan SHORT TERM...KH LONG TERM....MK AVIATION...Ryan