1-2 Snow Punch:
One of the beautiful things about weather is that all storms are not created equal.
Some come in fast and hard. Some take their sweet time.
This one is coming in 2 distinct pieces.
The first wave of snow this morning was a bit underwhelming in the metro. A general 1" to 2" fell, with 1.4" "officially" at MSP Airport.
Do I know anyone that lives at the Airport?
A few bands of snow may brush the metro from the west late PM & evening, but our PM "snow lull" is well timed for an easier than expected PM rush.
The good news? MNDOT and local city crews should have enought time this afternoon to have things in good shape for at least the early part of PM rush hour.
The models insist the "main event" will move in later tonight between about 10pm & midnight, and snow well into Tuesday morning.
NOAA's High Resolution radar (HRR) depicts a heavy snow band over MSP by about 11pm tonight.
There is a small bust potential if the next wave of snow does not set up right over the metro overnight. But all major models insist it will. I am not yet totally convinced the overnight snow will be as heavy as the models suggest, but I do think we'll get a good shot of snow overnight.
The usually trusty "Euro" is cranking out .45" liquid overnight. That should translate into about 4" to 6" snowfall overnight if it verifies.
The main event overnight should bring the heaviest snow between midnight and 7am. We should see snowfall intensity of .5" per hour for several hours...with a couple hours near 1" per hour in some spots.
If part 2 of this system performs as expected, It should deliver a good 3" to 6"+ additional snowfall overnight & Tuesday AM.
With the 1" to 2" from this morning, that should mean most of the metro and eastern Minnesota will end up with overall storm totals between 4" and 8" by noon Tuesday.
We'll get another major model run tonight just before the 2nd wave moves in...so I'll let you know if I see any changes in current thinking.
Here is the latest web briefing on what the Twin Cities NWS is thinking.
What could possibly go wrong?
Hi, Paul. I really like the explanation that you and your MPR weather colleagues have provided on the blog.
In the NWS's area forecast discussion (AFD), they mention a "trowal," or trough of warm air aloft. Could you explain to us what that means, and why it contributes to heavy precipitation?
Where did you find the HRRR image valid 06:00 UTC? The furthest out I can find is 03:00. Thanks.
Surprised the airport had 1.4. Here in Highland Park, not far from MSP, there was maybe 3/4".