Saturday 6 December 2014

'Painful' Cold to Stay Away Through Mid-December; Some Chilly Days on Tap

'Painful' Cold to Stay Away Through Mid-December; Some Chilly Days on Tap

Despite fears that the severe cold during November was a sign of what might ahead for December, much of the nation will be mild most days through at least the first half of the month.

According to Chief Meteorologist Paul Baker, "While the middle of November brought painful cold, temperatures will not drop off a cliff. There is no sign of winter getting worse any time soon."

Cold Records Shattered During November 2014

4,200NearlythismanydailyrecordlowsweretiedorbrokenintheU.S.duringNovember2014.3 daysNumberofconsecutivedaysinDenver,wherethetemperatureremainedbelow20F.Thiswasthefirsttimesincerecordsbeganin1872.Minus 27 FTheall-timerecordlowforNovemberwassetonNov.12atCasper,Wyoming.Theoldall-timeNovemberrecordwasminus21FonNov.23,1985.5 daysThenumberofdaysinarowtemperaturesdippedbelowzeroatGreatFalls,Montana,inNovember2014.Lowsrangedfromminus17tominus2F.10 daysThestretchofdaysfromNov.12to21,2014atChicagowithtemperaturesaveragingbetween14and24Fbelownormal.72.5 FTemperaturesfromSept.1toNov.30,2014averaged72.5FatVeroBeach,Florida,makingitthecoolestfallonrecord.Recordshavebeenkeptsince1942.

While there will be small pushes of cold air over the northern tier states during the first two weeks of December, these will tend to be brief.

The cold pushes from the northern Plains and the Upper Midwest to the Northeast will tend to last only a day or so. However, these can lead to minor rounds of wintry precipitation.

"We do not see any big arctic high pressures building southward out of Canada during the next two weeks or so," Baker said.

A fast west-to-east flow of air over the northern half of the nation will prevent smaller cold air masses from moving very far south for very long.

Most days from central Rockies to the central Plains, Ohio Valley and mid-Atlantic will bring near- to above-average temperatures for the first two weeks of December. Temperatures will average near normal in the South.

Temperatures farther north will fluctuate from day to day, but they will probably end up averaging close to the 30-year normal mark.

To put the temperature forecast in perspective, normal temperatures in the Northern states are about 10 degrees lower during early December, when compared to early November. The downward trend in normal temperatures does not bottom out until the middle of January.

The expected weather pattern will bring frequent storms to the Pacific coast. These storms will tend to weaken over the Rockies as they move swiftly to the Central and Eastern states.

We will be looking toward the western Pacific Ocean and the stratosphere for clues to when arctic air will return.

According to AccuWeather.com Long Range Expert Mark Paquette, "The track of Typhoon Hagupitand sudden warming in the stratosphere will be players as to how soon cold air returns and where the brunt of that cold air is directed."

"If Hagupit does not curve east of Asia or is delayed in doing so, the return to persistent frigid air in the U.S. may be delayed until Christmas or later."

Sudden major warming in the stratosphere often has a delayed and opposite effect in the lower part of the atmosphere. Stratospheric warming usually marks the beginning stage an arctic outbreak 14-21 days later.

"We suspect a stratospheric warming event may occur toward the middle of December," Paquette said.

There is the challenge of predicting which part of the Northern Hemisphere that the arctic air will move toward. A cold outbreak response to warming the the stratosphere is usually only directed to part of one continent.

In the meantime, people in the U.S. should not expect any widespread severe outbreaks of cold air through at least the middle of December and possibly later in the month.

The weather during the middle of December may get unusually warm over a large part of the nation, if Hagupit continues westward or stalls, instead of curving northeastward and away from the Asia mainland.



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