Winter Weather Advisory Until Midnight

A Winter weather advisory remains for portions of northern OK until midnight tonight.  This advisory includes the Tulsa metro area.

A winter weather advisory means wintry precipitation may impact travel today, so prepare for extra commuting time and use caution today and tonight.

Accumulating snowfall is likely today across the advisory area but this is not expected to be a major snow system.  Snowfall accumulations from 1 to 3 inches will be expected with the higher amounts generally located near the OK-Kansas state line.  The Tulsa metro may experience snowfall from 1 to possibly 2 inches.  Very little additional snowfall will be likely across the southern part of the state where 2 to 4 inches of snow fell Saturday evening and Sunday. 

A strong upper level system currently near western Kansas will move east across the central Kansas are by tonight before lifting northeast Tuesday morning.  A small area of vorticity is expected to move along the base of the trough across the southern Kansas and northern OK area today.  Some snow will develop as this system approaches, but the better and stronger dynamics and moisture will be north in central Kansas.  Generally light snow will be likely across northern OK at times today.  This system will be rather weak for northern OK compared to the winter events of the past 3 years. The system arriving today will produce snowfall from near 1 inch to possibly as high as 3 in some locations.  The Tulsa metro may see accumulations ranging from 1 to  2 inches. 

The next issue will be the arrival of the arctic air mass. Some light snow will be developing this morning but the bulk of the precipitation will be arriving midday and will end by late evening. The colder air will move into the region later today and will be entrenched into the region for most of the week.  NSSL data suggest the frontal passage will occur around 5pm tonight, but these types of boundaries usually arrive much earlier and stay much later.  I'll anticipate the boundary approaching between 1 and 3pm today.  This shallow and cold air mass will be very difficult to erode and combined with some snow cover, will continue to keep temperatures very cold for the week. This means temperatures will be below freezing until Friday.  Wind chill values Tuesday through Wednesday morning may be on the order of -5 to 14 and wind chill advisories may be needed for these time periods. 

As warmer air arrives Friday, temperatures will move into the upper 30s or lower 40s for highs through Saturday.  Some light precipitation will be possible as the relatively warm and moist air returns.  This may arrive in the form of drizzle.  The timing of this precipitation, if occurring early Friday morning or even Saturday morning, while temperatures are below freezing, could lead to some minor travel issues.  This remains a low probability, but something to keep in mind for the time period.

 Euro and GFS data also support another surge of arctic air Saturday night or Sunday morning and there may also be another chance of some wintry precipitation during this period.   Refinements will no doubt be made to the extended numbers as the GFS and EURO data are offering conflicting signals for possible solutions. I have elected to side mainly with the EURO suggestion of more cold air Sunday with a chance of snow.  I haven't totally sided with the temperature suggestions offered by the EURO for Sunday.  This would require morning readings near the 40s with falling temperatures into the lower 20s by afternoon.  At this juncture, I have used more of a blend from the GFS and EURO keeping Sundays readings, both max and mins, below freezing, but not nearly as cold as EURO would suggest. 

I encourage you to remain aware of your weather surroundings today as this winter event unfolds.