System Nearing Soon

Friday, February 20th 2015, 6:43 am

By: Alan Crone

Good morning.

We're tracking a very active weather pattern, including the chance for some light drizzle later this morning and midday, and increasing rain and thunderstorm chances tonight into Saturday morning.   A stout cold front will blast over the area Saturday bringing much colder air back to the region.   This air-mass will remain over the area through Monday.   Extremely cold air will move into the upper Midwest and northeast in a few days and we'll experience another significant chunk of this air-mass for late next week.

The upper air flow remains favorable for dislodging very cold air across the Northern latitudes and moving it southward.   A surface area of low pressure has developed across the Lee of the Rockies this morning extending southward into part of Texas.   This southern surface low will deepen along a quasi-stationary-warm frontal boundary located across or near the Red River Valley.   Cold (relatively cold) air is located north of this boundary across eastern and northeastern OK this morning and moisture is being drawn up and over the stationary front located south of our area.   The result is a stratus layer of clouds and the potential for some spotty drizzle or showers developing during the next few hours across portions of eastern OK.   Surface temperatures will be near freezing for a very small time window this morning, and this may result in a few areas of light freezing drizzle or rain.   Latest and greatest hi-res data support the precip holding off until later today when temps rise above freezing.   If you're area is below freezing and the light precip develops, use caution on elevated surfaces until temps rise above freezing. The odds are low.

The “warm sector" of the atmosphere probably remains well south of the Tulsa metro today.   This means our highs will be around the mid-40s while some locations across southeastern OK may move into the lower 50s.   Portions of north Texas could enjoy some highs nearing the 60s and lower 70s.   But the latest few runs of the Hrrr do bring some 50 readings to Tulsa this afternoon and will give cause to bringing our numbers up slightly. I'll make this call just before air-time.

Later tonight increasing rain and thunderstorm chances will occur as more moisture moves northeast into the region.   Most data support an increase in “elevated instability" and this means some thunderstorm activity may occur along the I-40 corridor into southeastern OK.   These storms would not be severe.   The best window for precip in the Tulsa metro will be later tonight into early Saturday morning.   After Saturday morning, the precip will be moving southeast out of the area.

Overnight into Saturday morning, the surface area of low pressure (wave) along the stationary front begins lifting northeast as colder air aloft influences the southern and central plains.   The result will be colder air moving southward across northern OK Saturday morning to midday and clearing the southeastern sections of the state by early afternoon.    Strong north winds will develop as the boundary pushes southward.   Extreme southeastern OK and northeastern TX may be positioned for a few thunderstorms as the cold front encounters the warm, moist, and slightly unstable atmosphere.

Temperatures Saturday could start in the 40s and 50s before dropping into the 30s and 40s late in the afternoon.

Sunday morning should start in the mid-20s and may only top out in the upper 20s near 30 in the metro.

A weak mid-level disturbance is expected to move across the north TX region Sunday night into Monday morning. This should generate some light snow showers across the Texoma region, and a few accumulations may be possible in the range of 1 to 2 inches.   Areas of southern OK into the I-40 corridor may experience some light snow or flurries pre-dawn Monday morning, but the likelihood of any snow into the Tulsa metro remains very low. We'll need to watch the “trajectory" of this wave closely.   A slight jog northward would bring some low end snow chances into the metro Sunday night or Monday morning.

Temperatures Monday will remain cold with lows in the teens and highs slightly below freezing.   A minor warm-up is possible Tuesday into part of Wednesday, before another very cold air-mass move into the area Wednesday and Thursday.   Our friends and neighbors across the upper Midwest, the northeast and northeastern Canada may experience their coldest air of the winter season.

Late next week, computer model data continues to offer a mid-level wave moving across the southern U.S. across the state Thursday into Friday.   Cold air will remain in place as this system draws near the area.   This could result in another chance of some wintry precipitation across the southern plains, and possibly Oklahoma.   It's too early to draw any conclusions with any confidence regarding late next week.   You'll read a lot of “buzz" on social media regarding this system.   But my advice is to ignore most of it, and just remain aware of a possible system late next week.

Thanks for reading the Friday Morning Weather Discussion and blog.

Have a super great weekend.

Alan Crone