TULSA, Oklahoma - Our much-advertised cold front will sweep across the area later tonight bringing rain and thunder chances this evening along with much colder weather this weekend.  Some snow, mostly light, will be possible overnight into early Saturday morning as the upper trough, mostly in the form of an open wave, brushes eastern Oklahoma.  Model data continues to offer some differing solutions with snowfall outputs, but the consensus remains for a low impact event with gusty northwest winds and low wind chills.  Some fog is developing this morning in some locations despite a solid stratus layer already in place across eastern Oklahoma. This will limit some visibilities for the early part of the morning.  Temps will be above freezing this morning for most of northeastern Oklahoma.  A few locations around McAlester to Stigler northeast to Fayetteville could have a slick spot with temps near freezing. 

Highs this afternoon should stay in the mid to upper 50s east with much warmer weather southwest of our immediate area where more sunshine is again likely for the day.  This was the case yesterday as the clearing line approached Tulsa county and halted for the day.  The main system continues to appear progressive (faster) in the data this morning and should bring the wind shift into northeastern Oklahoma between 7 pm and 10 pm.  Showers and storms will be likely behind the boundary, and possibly ahead of the front across southeastern Oklahoma.  A few strong to severe storms will be possible this evening, mostly in the form of some hail and gusty winds across southeastern and east central Oklahoma.  It appears that the deeper moisture and higher instabilities should remain across northeast Texas into southeastern Oklahoma. 

The pressure gradient will tighten up quickly overnight with northwest winds from 20 to 40 mph likely.  This will require a wind advisory for the overnight hours, including the Tulsa metro to the west.  Temps will also begin falling during this period from the 50s into the 20s by dawn Saturday morning. 

The data yesterday afternoon seemed to lock into the strength and nature of the trough as it was making its way onshore across the western U.S.  The observational weather balloon network (upper air radiosondes) sampled the system and new information was placed into the start files for numerical prediction weather models.  After these first runs with the trough onshore, the snow totals dropped some across northeastern Oklahoma and suggested a low impact snow event for eastern Oklahoma.  Now we’ll be watching the system as it nears for the state for any changes compared to model data.  And we’ll be watching to see if the system becomes stronger now than modeled.

The main upper level trough continues to display a mostly open wave and should quickly progress across the area late tonight.  If this is the case, any snow that develops overnight should be relatively light and mostly a low impact event.  The northwest winds at 20 to 40 mph will mostly blow any snow that does develop across road ways with little or minor travel impacts.  Only one model, the incoming NAM, attempts to briefly close the h5 trough directly over NE OK overnight.  If this scenario occurs, we’ll be facing more accumulating snows with some higher totals along the I-44 corridor into southwestern Missouri and some travel impacts.  At this hour, this model continues to be the outlier and any snowfall across northeastern OK should be relatively light and with low impacts.  Other models keep snow away from some locations all together. 

The larger inconvenience tomorrow may end up being the strong winds, colder air and the wind chills dropping into the teens.  Highs tomorrow afternoon could rebound slightly to near 30 as the system appears to rapidly exit eastern Oklahoma.  The latest timing supports the possible precipitation would be exiting the metro around 7 am and possibly out of the state between 10 am and noon. 

Sunday morning temps will start in the teens with highs rebounding into the lower 40s along with a return of south winds by the afternoon.  Our next system will quickly drop into the plains Monday night into Tuesday with strong south winds likely developing Monday from 20 to 40 mph across eastern Oklahoma with highs moving back into the lower 50s.  A few showers may occur late Monday night into Tuesday as the wave quickly moves east.  Another system may near Thursday or Friday with low impacts.

Remain aware of your weather surroundings for tonight through Saturday.  Winter weather systems can change quickly.  Data can still change for Saturday.