The first phase of our winter storm system is arriving Thursday morning through midday with a cold front moving southward across the state. 

Daytime highs will be reached around midday into the lower to mid-40s with temps falling into the mid-30s Thursday afternoon and below freezing Thursday night through Friday morning near and northwest or the Tulsa metro.  As the boundary moves across the area later Thursday, spotty drizzle or a few showers may develop across eastern Oklahoma, yet this chance will remain low. 

The main upper level storm system, currently well west of the state, will draw closer to the southern plains Friday while moving over the state Saturday.  The main impacts for northeastern and eastern Oklahoma are expected to occur late Friday night into Saturday before ending either late Saturday evening or pre-dawn Sunday. 

Impactful wintry weather is expected for northeastern Oklahoma.  Most of our discussion will center only upon northeastern and eastern OK, yet this system will have impacts statewide with significant icing possibilities across southwestern into central OK Friday evening. 

 

Our main issues continue to be specific parameters such as the location of the surface freezing line later tonight into Friday, and arrival of the main upper level system and its exact track, and the impact of transitioning precipitation types and accumulation. 

We have generally trended colder and more southward with the freezing line for tonight through Friday morning and midday.  This would set the stage, at least early Friday morning, for a very small window of freezing drizzle.  Yet most data support the bulk of precipitation remaining well southwest or south of our immediate area for almost all of Friday where temps will be above freezing. 

We’ll keep low mentions in the forecast for this unlikely scenario for Friday morning along and northwest of the I-44 corridor, with most of the area will remaining precipitation free until late afternoon into early evening as moisture begins moving northward into the area.  Temps at this point should be above freezing for most of northeastern OK with locations along the I-44 region to the northwest freezing by Friday evening. 

Icing is likely to occur during this period from late Friday into early Saturday from southwestern OK into possibly the central section of the state while remaining a cold rain across southeastern OK where temp profiles support warmer readings, at least above freezing.

Later Friday night into pre-dawn Saturday the main upper level system will be drawing closer to the state with colder air aloft spreading into northern OK.  Precipitation rates should increase during this time, yet the predominant type may be transitioning from freezing rain to sleet across northeastern Oklahoma. 

By Saturday morning to midday, sufficiently deep air aloft should support a sleet to snow profile to the surface across northern and central OK while southern sections along the I-40 corridor may continue to support a mix of freezing rain and sleet Saturday afternoon before changing to snow late Saturday evening.  The main system should be exiting the area late Saturday night, but a few areas of snow may remain pre-dawn Sunday across extreme eastern OK.  Again, I need to stress the exact track of the main upper level low will determine this exact location.  This may still change.

The transition from rain to sleet to snow is important in the accumulation process.  The longer a sleet profile remains, the lower the snow totals.  As of this morning, our forecast continues to call for 2 to 5 inches of sleet and snow for the Tulsa metro with higher amounts likely to our west.  This accumulation forecast is still subject to change.

Additionally, a small area of icing may occur near or southwest of the Tulsa metro with 0.10 to near 0.15 inches of ice from Creek County into southern Lincoln with amounts nearing 0.25 to 0.30 near OKC to almost 0.50 across southwestern OK. 

Locations along and south of the I-40 region, across southeastern OK, may stay mostly cold rain Saturday morning with some wintry impacts possible Saturday evening in the form of light sleet and eventually snow.  Locations across extreme southeastern OK will not be impacted by wintry precipitation but cold rain will remain likely.

Travel impacts are likely with this storm system across northern OK beginning late Friday evening and continuing through the weekend.  Cold weather will remain Sunday through Monday with some moderating influence likely Monday afternoon into the middle of next week. 

Key points:

A winter storm is likely to impact the state Friday into Saturday.  Southeastern Oklahoma has the lowest impact, with mostly rain. Southwestern Oklahoma into part of central sections of the state may have the greatest icing impact with some sporadic power disruptions. 

Locations along and north of I-40 have the greater chance of snowfall by Saturday midday to afternoon with locations west of I-35 experiencing the highest accumulations.  Locations near the Tulsa metro are expected to receive some accumulating sleet and snow Saturday.

Forecast specifics are subject to change depending upon the exact track of the upper level system and the exact location of surface freezing temperatures. 

Thanks for reading the Thursday morning weather discussion and blog.

-Alan