Cold Coming Soon

A quick-hitting Alberta clipper brought an inch or two of light, fluffy snow to the valley late yesterday, and strong winds behind the system caused some significant blowing snow and travel problems. A similar system may have an impact Wednesday night, followed by another clipper system late Thursday into Friday. This will be the most significant, not necessarily in terms of snowfall but because of the bittery cold air that will move in behind it. Friday, Saturday and Sunday currently look to be the coldest days, with lows in the double digits below zero and highs possibly only reaching the single digits above zero. Probably not the best weekend for outdoor activities...

Colder days ahead?

The Climate Prediction Center, in their daily medium-range outlooks, is indicating a high likelihood of below normal temperatures beginning sometime this weekend and continuing through at least the first week of February. While the coldest air may be just to our east across the Great Lakes and eastern Canada, it would appear that daytime highs in the teens to around 20 degrees will be common, along with nighttime lows around zero, possibly below zero if skies remain clear at night. There are no major storm systems in the forecast, but there will be periodic small chances for light snow as the cold air moves in. The long-range outlook for February calls for above normal temperatures, but this outlook will be updated next Wednesday, and if the cold air is firmly in place at that time, the outlook could be changed to reflect the latest trends.

Subzero, finally

The temperature went subzero for the first time this winter season (and for the first time since last February) this morning, with a low of -9 degrees. Clear skies and fresh snow cover made this possible, and I expect the temperature to drop below zero again tonight, despite what the forecast says. Just like the last day of a heat wave is usually the hottest day during the summer (and almost always hotter than forecast), the last day of a cold snap is usually the coldest (and again, almost always colder than forecast). I have no idea why this is. Anyway, with clear skies, the temperature should drop off fairly rapidly after sunset.

As for the snowstorm, accumulations were less than expected in most places, with a general three to six inches falling from late Sunday through Monday (4.3 inches locally). The next chance for snow is Thursday, with the possibility of a stronger system by early next week (still six to seven days away, so don't get too excited yet).

Winter Storm Warning

A winter storm warning is in effect through noon tomorrow. After days of waffling back and forth, the computer models have finally agreed on a solution that would bring several inches of snow to the area tonight. Light snow started about an hour ago, and should become heavier throughout the evening. The heaviest snow is expected to fall between 9:00 p.m. and 3:00 a.m. The current forecast calls for a total of six to eight inches by tomorrow morning. Blowing snow will also become a problem overnight.

Freezing Rain Advisory?

The weather service continues to confuse me. Freezing drizzle started around 10:00 this morning, yet they waited until after 1:00 to issue a freezing rain advisory. I don't know about the rest of the advisory area, but there hasn't been any freezing drizzle here since around noon. Seems to me like the advisory came a few hours too late. And why is it a freezing "rain" advisory when there is only freezing "drizzle"? Does a freezing drizzle advisory not exist anymore?

Numbers

Some statistics regarding our recent anomalous warmth:

*The average daily temperature has been above normal for 29 consecutive days (December 9, 2006-January 6, 2007)
*Of those 29 days, the high temperature was at or above 40 degrees on 23 of them, including two days in the 50s
*The high temperature has been above freezing every one of those 29 days
*The high temperature of 52 degrees on Wednesday was 27 degrees above normal
*No measurable snow has fallen during this time
*Seasonal snowfall has amounted to 4.9 inches, including 4.6 inches in November but only one-tenth of an inch in December

The next few days look to be about the same, with above normal temperatures in the 30s. The long-awaited (for some of us) change may occur by late in the week. This time period is actually going to be quite interesting. A cold front is expected to move through the region around Thursday. Once the front clears the area, it may stall just to our south. Low pressure could move along the front across the area, and this is where the situation becomes unclear. If enough cold air is in place at all levels, any precipitation would fall as snow. If the cold air is slower to arrive and temperatures aloft are still warmer, it would set the stage for freezing rain. Still several days away yet, so the forecast could change 874 times between now and then. Bears watching though.