TULSA, Oklahoma - We’re tracking two systems over the next 7 days including a significant surge of arctic air arriving for the weekend.  Rain chances will remain Friday evening before transitioning to a chance of some snow Saturday across northeastern Oklahoma and southeastern Kansas.  The snow chance is not locked in and may still change.  Before this cold air arrives, a fast-moving short-wave will drop across the plains with a slight chance for showers late Wednesday night into Thursday morning, mostly across far northern and eastern Oklahoma.  This chance will remain low. 

A noticeable warming trend will continue for the rest of the week, including afternoon highs today in the lower to mid-50s with some sunshine.  Highs will approach the upper 50s and lower 60s Friday afternoon before temperatures tumble Friday night and early Saturday morning.  Most data suggest subfreezing temperatures will remain for the entire weekend into Monday morning before modifying early next week.  

Low clouds remained entrenched across most of the area yesterday but started clearing from the west to east overnight.  While this clearing hasn’t totally continued across extreme eastern Oklahoma, we do anticipate that most areas will see sunshine today with a few clouds.   A few areas of patchy fog will be possible this morning, but widespread visibility issues are not expected.  A few spots will be near or slightly below freezing and freezing fog may provide for a slick spot or two in a few locations across east-central Oklahoma or northwestern Arkansas. 

Highs this afternoon will reach above our seasonal average with most locations reaching the lower to mid-50s along with south winds near 10 to 15 mph.  Wednesday should also feature rather uneventful weather with lows in the 30s and 40s and highs in the mid-50s with more cloud cover increasing across the area.  Winds will increase some from the south Wednesday as the above-mentioned shortwave moves across the central plains.  Our moisture appears rather low and void but there may be a few showers pre-dawn Thursday across the far eastern sections.  Temps should be above freezing for our area, but locations across east-central Kansas will be below freezing with a threat of some light freezing rain well to our northeast. 

Thursday afternoon into Friday the next upper level system will move across the western U.S. while a significant surge of cold air begins breaking from the Arctic and Northwestern Canadian region will sweep southward.  Pressure falls across Oklahoma will cause gusty south winds to draw higher dew points and warmer weather into the central and eastern sections of the state with highs in the upper 50s and lower 60s Friday afternoon.  The timing of the system may change, but as of this morning, our chances for showers and possibly some thunder will arrive Friday night as the front encounters the area with winds shifting out of the north and dropping temps into Saturday morning.  The main upper level trough, mostly in the form of an open wave, will move across the state with some rain changing to snow.  The data will continue to change for another few days, but most support some snowfall along and north of the Highway 412 corridor into southeastern Kansas.  Again, this snow chance is not a done deal and may continue to change.  Last night’s GFS trended the upper system more northward.  The EURO continues to be more of a closed low and moves right across the state.  We’ll not know for sure about the snow chances for another day or so, until the main trough approaches the western region of the U.S. allowing a better chance of good input data for the mode data. 

Strong northwest winds will create lowering wind chill values that will continue into Sunday.   Wind chills Saturday will be in the teens with Sunday morning readings from -5 to +5 across northern Oklahoma.  Saturdays daytime readings will be in the mid-20s.  Sunday morning lows will be from 10 to 15 and highs from 25 to 30.

A word of caution, again, regarding winter forecasts.  Changes in weather data, positioning of temperature profiles and exact timing of upper air features all play critical roles in any precipitation event, especially in winter when determining snowfall amounts and locations.   A difference of a tenth of an inch of precipitation in spring and summer is hardly noticed.  But a difference of a tenth of an inch of precipitation in winter could lead to a change in snowfall totals of 1 inch or more.  A 3 degree temperature change in summer in the 5000 ft level of the atmosphere is unnoticed.   A change of 3 degrees in the data during winter in this level of the atmosphere can mean the difference between rain and snow.   A change in positioning with a strong upper level system in spring means possibly a difference in the types of severe weather we could experience.  A change in positioning of a strong upper level winter trough could be the difference between snow-rain and nothing at all.   

The confidence level in this late week system is increasing, but there will continue to be some level of uncertainty.  We’ll keep you posted.