Wet start early Thursday AM
Snow chances ahead Friday, Sunday & Tuesday?
“Flu Forecasts” coming to a city near you?
Image: Twin Cities NWS
Growing snow chances ahead:
Some computer & internet issues today at the weather lab, so a quickie post on the latest model runs tonight.
We’re still on track for snow chances Friday, Sunday and possibly Tuesday. Current thinking still pretty much on line with what I posted earlier today, expect that the latest NAM runs are trying to hurry Sunday’s snow in here by Saturday evening.
Right now I see 4 distinct chances for precip through next Tuesday.
#1) Light rain and possible freezing drizzle tonight.
A weak frontal system sliding through Minnesota will trigger a few more December rain showers tonight. Rain chances should increase after about 10pm or so, and linger into early Thursday AM. Temps may hover near freezing overnight, especially north of the metro. Watch out for some possible icy spots overnight.
Warmer air pushing in Thursday should boost highs into the lower 40s, easing any possible early AM icy threat.
It will briefly feel like spring again by noon Thursday.
#2) Snow chances Friday:
Friday looks cold enough for “all snow.”
Weak low pressure zipping by to the south should be enough to trigger an area of light snow for southern Minnesota. This system has the potential to produce some 1″ to 3″ snowfall Friday onto Friday night, generally south of the metro to along the I-90 corridor. Redwood Falls, Mankato, Waseca, Rochester and Owatonna and the I-90 corridor cities may all see fresh snow and slick roads Friday.
Image: NOAA NAM model via College of DuPage
The Twin Cities should ride the northern edge of this system. Right now the NAM and GFS have the northern edge of the snow cutting of right over the metro. If that holds the central and southern metro could see a coating to about 1″ of snow by Friday night…with just flurries or nothing in the north metro. The far south metro could see 1″ to 2″
Stay tuned…the northern edge of the snow area could shift with Thursday’s model runs.
#3) Saturday night & Sunday:
All the major models are still painting a stronger system passing (just) south of Chicago Sunday. This storm track typically favors heavy snows of 6″+ in parts of Iowa and Wisconsin. If you are planning travel south or east along I-35 or I-94 Sunday expect snow. Saturday looks like the better travel day.
Most of the models bring a northern extension…or “baroclinic leaf” into Minnesota Saturday night and Sunday. If that happens, a fairly long duration, “light snowfall” event of 18-24 hours could set up over much of Minnesota.
Image: GFS at 6am Sunday via College of DuPage
If we can manage 18-24 hours of light snow as the upper low associated with the main storm to the south glides overhead, some decent snowfall totals could add up in the metro and much of central and south Minnesota.
It’s just too early to make a specific forecast of potential snowfall Sunday…but the Euro is cranking out .20″ liquid, and the GFS is closer to .37″ at this early point in the forecast cycle. At a simple 10:1…that might translate into 2″ to 4″ for some parts of southern Minnesota, and maybe the metro.
Image: Iowa State University
Again with caveats and caution in place…stay tuned….but be aware of snow chances from about midnight Saturday night through Sunday.
#4) Tuesday AM clipper?
The GFS likes the notion of brining a follow on clipper through Minnesota late Monday night into Tuesday morning. This could lay down another swath of a couple more inches…and potentially mess with Tuesday AM rush hour.
Again…it’s too early to be more specific.
Big picture? We’re moving into a colder pattern with a more active jet stream overhead that can bring several weaker snow producing systems into Minnesota. We may just nickel & dime our way to a few inches of snow…and a white landscape over the next 5-6 days.
Image: GFS 120 hour (5-day) snowfall totals via wxcaster.com
AH-CHOO! “Flu Forecasts” ahead?
“Mostly sunny & colder next weekend with a 40% chance of a flu outbreak.”
I don’t know if that’s exactly how it will work, but some interesting work is being done on forecasting flu outbreaks based on weather patterns by NCAR and Columbia University.
BOULDER – Scientists at Columbia University and the National Center for Atmospheric Research have adapted techniques used in modern weather prediction to generate local forecasts of seasonal influenza outbreaks. By predicting the timing and severity of the outbreaks, this system can eventually help health officials and the general public better prepare for them.
The study, published this week in the Proceedings of the National Academy of Sciences, was funded by the National Institutes of Health and the Department of Homeland Security. NCAR is sponsored by the National Science Foundation.
From year to year, and region to region, there is huge variability in the peak of flu season, which can arrive in temperate areas of the Northern Hemisphere as early as October or as late as April. The new forecast system can provide “a window into what can happen week to week as flu prevalence rises and falls,” says lead author Jeffrey Shaman, an assistant professor of Environmental Health Sciences at Columbia’s Mailman School of Public Health.
In previous work, Shaman and colleagues had found that wintertime U.S. flu epidemics tended to occur following very dry weather. Using a prediction model that incorporates this finding, Shaman and co-author Alicia Karspeck, an NCAR scientist, used Web-based estimates of flu-related sickness from the winters of 2003 to 2008 in New York City to retrospectively generate weekly flu forecasts. They found that the technique could predict the peak timing of the outbreak more than seven weeks in advance of the actual peak.