‘Battleground’ Weather Pattern Has Been in Place the First Half of February

The weather pattern in the first part of February has featured colder-than-average conditions in the West and northern Plains and near- or above-average temperatures in the East and South. In between has been an active storm track, or battleground, between those temperature regimes.

February has been dominated by cold temperatures in the West and northern Plains while parts of the South and East have been relatively mild, setting up an active storm track in the battleground between those extremes. That same weather pattern will likely hold through the end of the month.

A southward plunge of the jet stream has been entrenched from the West into the north-central states in the first half of February, keeping temperatures below average in those regions. Meanwhile, the jet stream has been riding northward over the eastern states, allowing temperatures to remain near or above average, particularly in the Southeast.

That general weather pattern is showing no signs of budging through the end of the month, as NOAA's 6- to 10-day and 8- to 14-day temperature outlooks show.

There is a very high likelihood of below-average temperatures continuing in much of the West as well as the northern Plains through the end of February. Portions of the Southeast, particularly Florida, have the greatest chance of temperatures remaining above average.

6- to 10-Day Temperature Outlook

A few daily record cold temperatures are possible in the West next week, while a few daily warm temperature records may be set near the Gulf Coast and in Florida. Austin, Texas, at Camp Mabry set a record for the earliest 91 degree temperature on Feb. 15.

A potential change from the first half of the month is increased chances of cooler air, at times, pushing into parts of the south-central states and Northeast.

The reason this weather pattern is staying so persistent in February is due to the negative phase of the Pacific North American Oscillation, or PNA.

When the PNA is in its negative phase, the jet stream is amplified far to the north over the northern Pacific Ocean. That helps to send a southward plunge of the jet stream into the western states, and therefore, keeps temperatures colder-than-average there. The negative PNA phase also typically means the Southeast is warmer than average.

February's Split Pattern So Far

The most severe cold this month has been entrenched from Washington to Montana and the Dakotas, where some cities were 10 to more than 20 degrees below average in the first 12 days of the month. A top-10-coldest Feb. 1-12 was recorded in several locations, including Great Falls, Montana, and Seattle-Tacoma International Airport, according to NOAA Regional Climate Centers.

Above is how many degrees above or below average each location has been Feb. 1-12, 2019.

On the opposite side of the spectrum, Atlanta, Charlotte, North Carolina, and Tampa, Florida, all had a top-10-warmest Feb. 1-12.

Winter storms moving through the active storm track in the battleground between those different temperature regimes have given some cities in the West and upper Midwest, including Seattle and Minneapolis/St. Paul, one of their snowiest Februaries on record.

In the warmer air along that battleground, multiple rounds of soaking rain have spread through parts of the Ohio Valley and mid-South, causing flooding in some areas.