Still Believing Mid December is When Winter Starts

Top Images are PNA forecasts

Top image EPO, Bottom Image WPO

(Pre reading notes: Taking into consideration you reading this may not be a weather fanatic, we have drawn out the effects certain phases have on the US. Pay no mind to the acronyms like PNA, WPO, EPO.)

We at The Weather Centre are standing firm in our belief that winter-like weather will start in Mid December, possibly even a bit later. This is because the indices drawn out above show very unfavorable conditions for winter weather going into the final weeks of November. As the indices on the bottom 2 rows images are positive, this will keep the US warm, particularly in North and East portions of the country. The much more stubborn images on the very top showing long blue negative lines are also unfavorable, and unless that particular index goes positive very soon, we won't be seeing winter weather until a week before Christmas (which may be a plausible theory). Do not be put down, winter weather lovers, because we do anticipate winter to end later than normal as we go into spring. But that is another story for another time. If we see these indices change, we will certainly let you know first.

Potential for Severe Weather Tuesday?

Forecast instability for mid-day Monday. Higher instability = more severe storms.

The 18z GFS is showing the potential for some severe weather in the south in the next couple days as warm air is dragged north, and hits the drier air, thus producing some nasty storms. We are anticipating these storms to form sometime between Monday and Tuesday, and they may be intense. While looking at vertical velocities, we see that velocities will be high in this time period, indicating lifting mechanisms, in turn indicating thunderstorm activity may be present. A front or possibly a dry line will be attached to a low pressure system that will be moving east. This front/dryline will serve as the starting point for thunderstorms.

Tonight's Forecast

Highlights in the forecast:


•Rain entering Texas
•30s from Wisconsin east into Northeast region
•40s across Plains as warm front moves through
•Lake effect precipitation in Northeast region
•Dry across Southeast as ridge in place
•Snowy in the mountains in the Northwest
•California coast wet, higher waves as low pressure system spins offshore
•Breezy in Texas

ECMWF Indicates Cooler Air to Enter North US as NAO Dips Negative

In a move we've been predicting for days, the NAO index should move negative, allowing some colder weather to enter the North US region. The ECMWF has latched onto this solution, as seen below in the 850 mb picture 5 days out.

12z ECMWF NAO

The NAO should be enough in negative territory that this cold air moving into the North Plains should occur. The big obstacle, however, is the very strongly negative PNA pattern that should sustain itself over at least the next week. This will likely provide a bit of trouble for whatever colder air may come into the US. When this PNA is strongly negative, it can make for a warmer solution across portions of the east US.

Major Updates to Pages

We have introduced major updates to the Weather Models page and Winter Weather Wall page.
Click on the links above to see the updates.