Posted at 5:37 PM on February 21, 2013
by Paul Huttner
Filed under: Winter 2012-13
It's called a "nowcast."
That's the point when the forecast models have pretty much set the table with an incoming storm, and the radars begin to light up with rain or snow.
We watch radar and satellite trends. Do they fit the story the forecast models have painted for the storm? We watch surface reports. Is there "ground truth" to the radar and satellite trends?
Tonight we watch the radars light up from the south, as the "snow shield" crawls slowly north from Iowa.
This storm has performed as advertised so far, dumping over a foot of snow in parts of Kansas.
In this edition of Updraft we track the snow shield as it moves in, forecast a snowy Friday AM rush hour and count up the inches as the system rolls in.
The "forecasting" is over. Let the "nowcasting" begin.
What you should know now:
-Latest Twin Cities radar loop
Midnight to 3am snowfall approaches the Twin Cities from the south
Friday AM rush falling snow and temps in the 20s with slick roads & freeways
2" to 5" snowfall expected in the Twin Cities by Friday evening
14" snowfall in Rossville, Kansas Thursday (just west of Topeka)
12" snow totals in Olathe, Kansas (southwest Kansas city suburb)
Thundersnow reported in Emporia, Kansas
2" per hour in Ottumwa Iowa Thursday afternoon
PRELIMINARY LOCAL STORM REPORT NATIONAL WEATHER SERVICE DES MOINES IA 436 PM CST THU FEB 21 2013
0435 PM SNOW M4.3 INCH 1 SW OTTUMWA IA TRAINED SPOTTER
SINCE THE SNOWFALL STARTED AT 2PM.
TRAINED SPOTTER REPORTS NEAR WHITE OUT CONDITIONS ON EAST SIDE OF EMPORIA. THUNDER SNOW WITH HEAVY SNOW FALLING AND DRIFTING.
Snow Crawls North:
Radars are lighting up in Iowa and southern Minnesota tonight as the northern edge of the snow shield with our next system crawls slowly north.
The leading edge of snowfall crosses the Iowa border tonight, and arrives in the Twin Cities mainly after midnight. It may take some time ot get here as the system bucks dry air over the Twin Cities, but by 3-4 am, snowflakes should be flying close to and in the metro.
Twin Cities NWS does a nice job of breaking down the timing on the incoming system in this "Weather Story."
Snowy Friday AM rush hour:
Your Friday AM commute will feature some snow.
It may not be a major system in terms of inches...but the effects will be there with falling snow Friday morning and temps in the 20s. It doesn't take much to produce icy wheel glaze on ramps, bridges and intersections. Give yourself some extra "stopping distance" Friday.
Here's the latest road and traffic conditions and cameras around the metro from MNDOT.
Heaviest snow totals in southeast Minnesota:
The system is weakening as it moves toward Minnesota. I don't think we'll see any 12"+ totals that the storm produced in Kansas Thursday.
2" to 5" seems like the best bet for the metro. There is a decent shot at a few 6"+ totals in southeast Minnesota and western Wisconsin.
Right now the weekend looks quiet, with a chance for more snow as another system tracks into the Upper Midwest Monday.
The latest trends are taking that system a little further south & east...and that may mean potentially less snow for the metro.
30s by Sunday and next week will feel remarkably nice after our "Frigid February!"
Enjoy the fresh snow!