TULSA, Oklahoma - Things appear on track regarding the next system arriving later this afternoon and tonight with some rain chances followed by a warm-up before a major pattern change brings frigid weather back to the state.   Highs today will be in the upper 50s and lower 60s with some morning fog underway across portions of eastern Oklahoma.  Visibility may be reduced in some locations this morning but widespread fog issues are not expected in eastern Oklahoma as low-level flow and south winds should help us out.  As the visibility improves, high and mid-level clouds will quickly arrive as a mid-level southern stream system ejects across or near the state today bringing a chance for some rain back into southeastern and part of northeastern Oklahoma.   A rumble of thunder may be possible as the cold air aloft moves across the area but most activity will be thunder-lightning free near the metro with any lightning more than likely confined to southern Oklahoma. The system will quickly exit the area about early tomorrow morning with clouds eroding from the west to east by later in the day.   One big difference in the last two runs of most data point toward increasing water values.  This means some pockets of moderate rainfall may occur with this system, more so in southeastern sections.   Nice! We’ll take it!

The main upper level pattern will find a major trough developing across Hudson Bay with a mid-level ridge posited off the west coast nudging northward into the western Alaska region.   A fast-moving clipper will move from Canada into the Midwest over the next 36 to 48 hours with a medium to long wave trough rounding the base of the vortex and moving quickly across the central plains.   A strong surface high from 1050 to 1055 mb will build across the northern plains into the central U.S. Sunday into Monday helping to bring very cold air into the nation.   These features, while not text book, do conform to the McFarland signature that usually foretells the southward expansion of arctic air.

Before the first frontal intrusion arrives, we’ll experience another run-up with highs Thursday afternoon in the upper 60s to lower 70s.   Strong south to southwest winds from 20 to 30 mph will increase the fire danger to elevated levels across part of the region before the front arrives later Thursday night.   Shallow and cold air masses will typically arrive slightly faster than most model data depictions.   So this means the wind shift and temp drop will more than likely occur Thursday night late with temps dropping quickly into the lower 30s Friday morning.   As the front passes a few showers or some drizzle may develop along with the deck stratifying directly behind the front and over the cold air.   Friday afternoon highs may stay in the mid to upper 30s despite the computer guides suggesting around 40 or so.   Northwest winds will remain quite strong from 15 to 30 mph helping to create some noticeable wind chills.

Saturday into Sunday another surge of colder air will arrive as a medium length trough passes across central Kansas into northern Oklahoma.   This feature is the one that may bring some light snow showers near the state late Saturday night into Sunday morning to midday.   Again today, the GFS is more south with the snow shower activity compared to the EURO which seems to shear-out the lift across southern Kansas Sunday.   As this point, our forecast will continue to keep rather low mentions of snow showers across northern Oklahoma for the period as even colder air moves southward.   Sunday morning, Christmas Eve, will feature lows in the mid-20s with highs in the upper 20s or lower 30s along with clouds and northeast winds.  

Monday into Tuesday should present very cold and dry weather but the data this morning has waffled slightly with the positing of the coldest air.  I’ll stick with previous numbers before making any changes to these periods.   If we do make some changes, it will be to increase the highs Monday and Tuesday to the upper 30s near 40.   As it stands now, the clouds may attempt to thin in spots and would allow Christmas morning lows in the mid-teens with highs in the upper 20s to lower 30s.   Tuesday morning lows will also be in the lower to mid-teens with highs in the lower 30s.   Another system may be nearing the state by the middle to end of next week.

Thanks for reading the Tuesday morning weather discussion and blog.