Old Fashioned March
Yes, we're all sick and tired of hibernating. Winter came late, and it came hard - a far cry from last year's Memphis-like conditions. So far: one 40-degree high in March.
According to Michael Griesinger at NOAA the Twin Cities have averaged 17 days at or above 40F in March since 1980. This will be the first March since 2002 with fewer than 10 days of 40+.
Last year freakishly strong west winds aloft swept mild, Pacific air into Minnesota. By late March flowers were blooming, ice off many lakes. Instant May. This year prevailing jet stream winds are unusually light. No warm winds from Seattle & Vancouver - allowing Canadian air to linger week after chilling week.
A quiet week is shaping up; highs top 40 by Thursday or Friday. The normally reliable European model is hinting at 50F with scattered T-showers a week from tomorrow.
Let's hope for a gradual thaw in coming weeks. Sudden warmth, coupled with rain, could unleash the 3-6 inches of water in the snow pack up north. NOAA says a "concrete frost" over southern Minnesota (saturated, frozen ground near the surface) means rain or melting snow will immediately run off, much like it does on concrete. What a strange pattern.
* photo above courtesy of Tom Purdy.
The interesting tidbit to me though that came from this stat is that this will be the first March since 2002 where the number of days in March with a high of 40 or more will be less than 10! From 1873-2012, the Twin Cities has averaged 13.6 days in March with a high of 40 or more, though this number goes up to 17 if you only look at 1980-2012. Based on our 1980-2010 averages, the average high hits 40 on the 13th...so there are 19 days (13th-31st) where the average high is 40 or more.
Of the 139 March's between 1873 and 2012, 37 years have had fewer than 10 days with a high of 40 or more in March (27% of all years). However, only 3 of these 37 March's have happened since 1980! That would be just 3 out of 33 years since 1980 (84, 01, 02), or 9%! The other 34 years all came from 1975 and earlier. Needless to say, based on recent history, what we have seen for cool temps this March has been very rare, though this type of March was more common from the 1870s through the 1970s (32% of March's from 1873-1979 had fewer than ten 40 degree highs)!"
* Montevideo on the Minnesota River
* Granite Falls on the Minnesota River
* Redwood Falls on the Redwood River
* New Ulm on the Cottonwood River
* Long Prairie on the Long Prairie River
* St. Cloud on the Sauk River
* St. Cloud on the Mississippi River
While severe to extreme drought conditions still exist across the region, precipitation from December 2012 through the first part of March has been near normal to even above normal in some areas. Hence, some regions do have a decent snow pack with water equivalents of 3-5". The graphic (above) shows the amount of water in the snow pack on March 6, 2013.
In addition to the more common river flood threat, this winter parts of Minnesota and Wisconsin have concrete frost. Concrete Frost is when the top layer of soil becomes saturated and is solidly froszen. Until it thaws and allows moisture to travel through the soil, any rain/snow melt will run off similar to how it does on concrete. The image below shows the areas of concern for Concrete Frost and potential quick response flooding."
* The NWS will release their next flood outlook on March 29.
Latest from Alerts Broadcaster:
* As we predicted Saturday, the probability of significant snow in New York City remains low - the most reliable weather models show temperatures 1-2 F. too warm for a major snowfall in the city. It'll be a close call, but there's simply too much warm air for a big pile of slush.
* A cold rain spreads into New York City tomorrow, possibly ending as a little slush in the suburbs Monday evening - but air temperatures above 32 F. should keep most roads wet. The brunt of the storm's precipitation/winds should pass just south/east of NYC tomorrow and Monday night.
* Some models print out as much as 4-6" of slushy snow for south Jersey, but I suspect the heaviest snows will remain over western and central Pennsylvania, western Maryland, and the hills of western Virginia and West Virginia. Philadelphia may pick up 1" of slush, maybe a couple inches of snow for the western suburbs of Washington D.C.
Summary: Full disclosure. This is a tricky forecast, with New York City, New Jersey and Philadelphia right on the rain-snow line. A degree or two makes a big difference in a scenario like this. Odds still favor mostly rain, and even if a changeover to wet snow takes place PM hours tomorrow ground temperatures above 32 F should ensure mostly wet roads. Some slushy accumulation is possible on lawns and fields, especially south Jersey, but this storm will not rival the major systems that came thru in February and early March. Significant rain for coastal areas, coupled with strong winds (20-35 mph), will result in slow commutes and possible delays at area airports tomorrow. Conditions improve rapidly Tuesday as this storm sails out to sea. No, spring can't come soon enough this year.
Graphic above (adjusted for inflation) courtesy of Karen Clark & Co.
* thanks to meteorologist Todd Nelson for doing a great job on the Star Tribune print and blog while I was away.
Graphic credit above: "Image of massive Arctic sea ice cracks showing temperature of the ice and the cracks between floes." Via Arctic Sea Ice blog.
Graphic credit above: "Warming projections to 2080 from Rowlands et al. in Nature Geoscience 5, 256-260 (2012)."
"...the marriage of capitalism and climate remediation...What if corporations shoulder more costs and lead the technological charge, all for a huge potential payoff?...Let's hope we are unleashing enlightened capitalist forces that just might drive the kind of technological innovation necessary to genuinely tackle climate change."
Photo credit above: "In zombie movies such as Dawn of the Dead, 'zombies are never destroyed and no new stable order emerges. And that, I fear, may be the truth of the climate change story'. Photograph: Ronald Grant Archive.