TULSA, Oklahoma - Our first winter precipitation event of the season is expected to impact portions of northern and eastern Oklahoma today with rain changing to snow by early morning with some accumulations likely, at least on elevated to grassy areas.   A winter weather advisory is underway until 6 p.m. for a large portion of northeastern Oklahoma, including the Tulsa metro.  Currently, locations along I-40 and into east central Oklahoma are not included in this winter advisory. 

Rain will quickly transition to snow by early this morning as cold air sinks southward as another stout cold front moves across the area.  Additionally, the approach of an upper level system will bring colder air aloft to the region which will also aide in the precipitation potential.  The precipitation will be ending from the west to east by midday to afternoon as dry air entrains into the system with cold weather remaining for the next few days.  Tuesday and Wednesday should feature morning lows in the upper teens to lower 20s with highs in the mid-30s Tuesday and into the 40s Wednesday.  The pattern will change by midweek allowing some moderation with highs Thursday approaching the lower 50s and Friday into the mid to upper 50s.  Our next front appears to move across the area by Saturday bringing some chilly weather again into Sunday.  Saturday morning lows are expected in the mid-30s with highs in the mid-50s while Sundays highs will top out in the upper 40s.

Precipitation is underway this morning across northwestern and western Oklahoma where a winter storm warning remains in effect through noon.  Light rain is currently falling across southern Kansas and part of northern Oklahoma as the main upper level system is nearing the state while precipitation should begin across southern Oklahoma with warm air advection processes as stronger winds aloft approach these regions.  The initial phase should support rain but will eventually transition to snow once the colder air aloft moves across these areas along the I-44 corridor.  Our forecast continues with a 1 to 3 inch range along the I-44 corridor region.  Banding could result in locally higher totals near this zone.  Ground temps are typically warm for this time of year which would favor most accumulation on elevated or grassy surfaces.  But the rate of falling precip also has a role in this process.  The higher rate per hour could overcome the relatively warm ground temps and cause travel problems and the winter weather advisory products currently acts to communicate not only the accumulation potential but also the potential for some travel issues.  The main window for wintry precip for the metro will be approximately from 7 a.m. to 4 p.m. 

As this system exits the area, cold weather will remain for the next few days along with wind chill values Tuesday from the single digits to teens.

Remain aware of your weather surroundings today and drive cautiously and slowly in areas that do receive winter precipitation.