NA February 2012 Weather Discussion
Posted 03 February 2012 - 06:39
Due to the thick fog and "chilly" temperatures, everything is covered in hoar frost. It's all white on white on gray outside as even the pine/spruce are frosty white. Today, no groundhog would have seen his shadow here as visibilities didn't get much over 1 mile the entire day with very low ceilings and stagnant conditions with temperatures reaching the upper 20s. The fog quickly moved back in at dusk and driving home tonight I had to go pretty slow because it was very hard to see.
Temperatures will continue to be mild over the next several days. Fog will last at least to mid-day tomorrow with clearing skies and light winds. Highs will be 36˚F tomorrow and 38˚F Sunday. Temperatures will fall back to around 25-30˚F and then again as more seasonable temperatures move in... but another warm up is predicted for next week.
Right now the 8-14 day period looks mild with near normal to drier than normal conditions expected. I saw March 2nd, 2000 show up in the analogs, which was during a record mild spell that saw the abrupt end to what had already been a non-winter. It is possible we could see that again this year. There have been many similarities to 1999/2000.
What is interesting is that despite the very mild January here and over most of the U.S., was that global temperatures fell to 0.09˚F below the 1981-2010 average in January according to the satellite measures. But it's not all that unusual to see cooler global temps during a La Niña while much of the U.S. remains warmer than normal... just as the opposite often occurs during El Niño.
Posted 05 February 2012 - 00:04
February is typically our driest month of the year. The 1981-2010 normals brought the averages up over the 1971-2000 norms, however... from 0.57" to 0.68". January stayed about the same, rising from 0.69" to 0.73" and December went up significantly from 0.68" to 0.79". November, however, went down significantly from 1.71" to 1.35". The USDA also issued new hardiness zone maps for the U.S. for the first time in 20 years, using 1975-2005 as a base period. Bemidji moved from zone 3a to 3b, meaning the average coldest winter temperature moved from -35 to -40˚F to -30 to -35˚F. It can be deceiving since many winters still see temperatures to -40˚F or colder. At the same time, a few winters in the 1975-2005 period only saw temperatures to -20˚F.
Anyway, yesterday was a sunny day with a high at freezing and today was overcast with temperatures in the upper 20s. The temperatures have verified a bit cooler than the forecast the past few days, especially due to dense fog that forms as temperatures drop at night, keeping the sun from heating up the low levels of the atmosphere until mid-day. More patchy fog can be expected tonight and tomorrow will be a mild day with 40˚F a possibility before temperatures cool down with a passing front and a strong high pressure center up to 1040mb expected to be centered over the region.
The GFS 18z run has colder temperatures, but generally dry weather until week 2, where it shows a couple storms potentially impacting the area. This would be welcome. Unfortunately I've seen similarities lately to 2005/06 as the global pattern has been similar. I hope spring and summer don't turn out like that year. We had a serious drought and the hottest July since the dustbowl in 2006. But other dynamics in the climate system are much different than 2006... and with the great variability of our weather, a couple thunderstorms or winter storms can make the difference between feast and famine here.
Posted 21 February 2012 - 23:22
With the exception of a few cold days with lows in the -10s and highs in the single digits above zero, it's been quite mild and February is running 7.5˚F above normal. The 4-5" of snow we had on the ground slowly consolidated and melted down to 1-3" with many areas with no snow at all... but a system moved through yesterday and we've received 3" of snow so far. It is still snowing very lightly.
There is a chance for light snow Thursday with an inch or two possible before a bigger chance late this weekend. The models are showing a storm dipping into the Northern Rockies and then moving across southern/central Minnesota. It will strengthen once it reaches the eastern Dakotas. Currently the mid-range forecasters from NOAA have issued an advisory for heavy snow from the storm encompassing much of Minnesota into Wisconsin.
Of course it's still too far to really tell as the storm could track south or north of the current model prediction and greatly change amounts.
In any case, it seems we'll be in a pattern for a while here with more frequent chances for snow and cold temperatures... though no really unusual cold is forecast and the average is still above normal.
This will definitely go down as one of the mildest winters on record. And it now appears that an El Niño is going to develop for next winter... so it could mean two mild winters in a row as El Niño winters are almost always mild and benign.
Posted 22 February 2012 - 02:52
One very noticeable characteristic of this winter here is that we have had much less snow than usual. We've had numerous light snowfalls of 1 or 2 inches but not very much more.
Why has this winter been so mild? If my memory is correct, the flow pattern across the North Pacific and across North America and the North Atlantic has been strongly zonal for much of this winter and since we were mostly in this zonal flow from the WSW we haven't had many incursions of very cold air from the NW. However North Western North America has had a much colder and snowy winter than here.
The zonal pattern started to break down and become more meridional some weeks ago and that coincided with very cold Siberian air moving into Eastern and Central and Balkan and Southern Europe.
Maybe the finite quantity of very cold air (below -40C/-40F) usually centred over Siberia, either moves across Alaska and the Arctic Ocean into northern Canada or else it flows towards Europe or Afghanistan or wherever. So maybe our lack of really cold weather this winter was because the available very frigid air went somewhere else rather than here.
Looking at the circulation at the 500 millibar level, the jet across the North Pacific and the North Atlantic has been unusually strong for much of this winter.
Maybe there's a simple reason and explanation why this should have been so , but I don't know what it could be.
Posted 24 February 2012 - 16:04
We currently have a winter storm watch for Saturday night into Monday morning as a low pressure center will track down from British Columbia and Alberta into Montana and the Dakotas before strengthening again and moving across central Minnesota. The models have been backing off on the potency of the storm... but 6" accumulations are possible, especially in northern Minnesota.
The models are still fighting about the storm that will come right on the heels of the Sunday storm. The European 00z for today shows a pretty potent winter storm moving SW to NE across the plains into Minnesota and would dump over a foot of snow over a pretty large area. Other models are keeping the track further south, however.
Otherwise the jet stream will be fairly zonal in the next 2 weeks with a southeast ridge and a broad trough across the central and western U.S. Temperatures will oscillate around normal here... which is highs in the mid to upper 20s with lows just above 0˚F
Posted 24 February 2012 - 16:10
The topography of the Arrowhead also lends itself to higher snowfall.. so even in lean years like this where much of central and southern MN has brown ground... the northeastern corner of the state has consistent snow of at least 12". Snowfall is enhanced along the north shore of Lake Superior when east winds blow and the air rises about 1000' over a short distance. Snow showers, though fairly light, will also often break out inland with a NNW wind simply due to instability in the atmosphere and the varied terrain. This sometimes happens in Bemidji as well since we are close to the continental divide and the highest point in this region of the state.
Posted 24 February 2012 - 19:20
The late winter often brings heavy snow to this area but following about 7th March it rarely gets really cold.
Posted 24 February 2012 - 20:44
The 2nd storm will be much more potent. The Navy NOGAPS and Japanese models show the storm moving into Iowa and then shunting eastward with a much weaker system overall... but the other models are banking on less low level cold being available to push the storm southward... which is why it would be able to spin up and become a powerful storm.
In any case, the models are generally calling for an active pattern here as storms move across the northern U.S., bringing frequent chances for light snow outside of the two big storms.
Posted 27 February 2012 - 01:05
Another storm will drop into Colorado before moving into southern Minnesota on Tuesday night and Wednesday. This storm will have ample moisture and could bring snow totals well in excess of a foot to parts of central Minnesota. At this point, Bemidji will be on the northern edge of the storm and could receive up to 6". The track is still uncertain, and after progressively tracking southward in the models yesterday, they are now taking it a bit further north again.
Beyond that, there is another chance for snow going into the weekend... though that event will bring light snows of a couple inches. All in all, this snow will do a lot of good in easing drought fears. A few weeks ago, most of central and southern Minnesota had no snow cover and there were fears of a potentially severe spring fire season. Those fears are now laid to rest since the snow will provide moisture for the soil and it has also pressed the grass down to the ground. Standing dead grass burns much quicker than matted down grass, which tends to hold snow melt water underneath it by blocking the suns rays from reaching the soil.
Temperatures will remain at or slightly above normal with highs in the 20s and lows around 10˚F. This will be a boon for the Snowjourn Cross Country Ski race scheduled for Saturday. The more famous Minnesota Finlandia Nordic ski race was able to go on on a shortened course with intensively managed snow. I'd bet many that might have skipped out on the race due to poor snow conditions will take part in the Snowjourn this weekend.
The longer range outlook sees troughing into Alaska, western and central Canada, and the northwestern U.S. with a flat ridge over the Pacific and the Southeast U.S. This will keep a relatively fast, zonal flow. The ridge in the southeast and off the west coast will allow some storms to dip south and then move north, which will allow them to strengthen... bringing increased risks of severe weather.
Posted 27 February 2012 - 13:54
Unfortunately yes! We get a cold day here or there, but for the most part feel like I am stuck in a never-ending summer. It just seems wrong to wear flip-flops and shorts in February. Not only that, but allergy season has arrived early as well. But then the Cajun Groundhog did not see his shadow so we new winter was over
We do have a bit of drizzling rain at the moment, and the fog is heavy. I can barely see out of my office window. We have a potential for severe weather on Wednesday and Friday, so I'll be keeping an eye on that.
Posted 28 February 2012 - 09:12
The weather has certainly become quite interesting here. With the 5" of snow last week and the 8" we got yesterday, we've doubled our snowfall total for the season... and the 12-14" we have on the ground is definitely the deepest it's been all winter.
The Grand Forks NWS office is really getting on my nerves. There are blizzard warnings and winter storm warnings up all over the place... but their jurisdiction continues to be only watches despite the near certainty of a major winter storm tomorrow through Wednesday. The models had been trending southward with the storm through yesterday morning, but have since trended further and further north... putting Bemidji well within the major storm area.
The European is the most bullish on the storm with upwards of 1.05" of liquid precipitation equivalent set to fall in Bemidji. Assuming an average 10:1 ratio of snow to water, that'd be 10" of snow. I'm going to err on the conservative side and say 6-10" total for Bemidji with a tight gradient to our north.
Some areas south of here across central Minnesota could see well over a foot of snow. My university has 1 to 3" tomorrow, 10-14" tomorrow night, and then a few more inches on Wednesday in the forecast.
The Twin Cities will likely see 4-8" of snow with some rain/sleet/freezing rain mixing in at times as the warm air is pulled north with the storm. Areas south of there will likely see mostly rain.
There is another chance of snow Thursday night into Saturday, however the models are pulling back on that system and strengthening it further east... still, an inch or two could fall.
If we do get 10" of snow from this system, it would put the February snow total at 23"... certainly one of the highest on record, considering February is our driest month.
Beyond the next week, the pattern will shift to a very mild setup with a large ridge across the eastern U.S. and the trough pulling back into Alaska, western Canada, and the west coast of the U.S. The models disagree on how warm it will get... especially since region-wide deep snow cover will keep temperatures down... but generally temperatures will be near or above average. By mid-March, average highs are around 35˚F and lows around 15˚F... with 3 more minutes of light each day, daily average temperatures move up quickly. I'm already itching for spring as I plan to grow a big vegetable garden this summer.
Posted 29 February 2012 - 21:49
Posted 07 March 2012 - 01:39
Here are the stats for February:
Avg temp: 17.8˚F/-7.9˚C Departure: +6.4˚F/+3.6˚C
Avg High: 27.4˚F/-2.5˚C Departure: +3.4˚F/+1.9˚C
Avg Low: 8.2˚F/-13.2˚C Departure: +9.2˚F/+5.1˚C
Highest High: 39˚F/3.9˚C on the 5th
Lowest High: 5˚F/-15˚C on the 10th
Highest Low: 30˚F/-1.1˚C on the 20th
Lowest Low: -13˚F/-25˚C on the 10th
Liquid Equivalent Precipitation: 0.92" (+0.35")
Snowfall: 15" (+6")
Overall February was milder than average, especially in morning lows due to much cloudier than normal conditions. A mild Pacific flow dominated for much of the month, which at times did bring bouts of moderate snowfall, making it the snowiest month of winter 2011/12 so far (the snow season runs from July 1st to June 30th, and spring storms can make March and even April the snowiest months of the winter in many years).
While the higher than normal snow fall has brought the snow pack to near normal levels, it did not make up for the lack of snow in December and January. Even so, snow pack water content is 2-3" in the Bemidji area, which is actually not far from the average.
Interestingly, even though February 2012 was still 6.4˚F above normal, it was the coolest meteorological winter month (DJF) relative to normal. Both December and January came in at 8+˚F above normal, making winter 2011/12 one of the warmest on record (though 1930/31, 1986/87, 1997/98, 1999/2000, and 2001/02 were warmer than this year).
With another 4" of snow having fallen in March so far and a mild, wet pattern in the offing... the fears of drought have been greatly eased across the region.