::7.5" of New Snow Reported
Lakevilleweather.com has reported 7" of new snow has fallen from the stom that is currently tapering off across the SE quarter of MN this morning. Snow began to fall between 1530 and 1630CST, and was falling in earnest by 1800CST. We took measurements throughout the night...beginning around 1900 and then again every 1-1.5 hrs or so thereafter. As of midnight, 6.55" had fallen, officially giving us the "reportable" amount of 7". Overnight only yielded an additional 0.70", which brings storm total to 7.25", which is reportable as 7.5"...our official report as of this morning.
As was dicussed by the MPX-WFO dayshift team yesterday, this storm almost snuck up on us, as modeling had not really tagged the H70 low that developed on the lee of the Front Range late Satudurday, early Sunday, and quickly deepend over the NE plains and raced across the Sioux Empire, swinging up some moisture from the Gulf, vis-a-vis a strong coupled jet...both the LLJ and the upper jet streaks were aligned perfectly to transport the needed moisture, and with a solid, cold, cP airmass at the surface, the snowfall eruption was hard to miss once it was in the numbers.
Another very prevalent feature of this "surprise" system was the gregarious frontogenesis which occured overnight was well. First indications came with the OK icestorm, as the H70 low had kicked off the inversion which caused the widespread FZRA, and winds began to wrap around the low beginning the frontogenesis...Now, widespread convection has formed along and ahead of the sfc front as it pushes ENE, bringing the H70 up to the Finger Lakes of NY by 00Z tonight.
For our region, the airmass behind the front only grants stability through general subsidence, as temps in the mid-layer of the atmosphere remain relatively consistent through the next 24-36hr period. This makes a forecast challange out of temp progging at the surface, as the snow pack will inevitably impact the final numbers. Partial clearing today will not grant much solar heating due to snowpack, and therfore will bump the MOS temps down a bit.
Next chc for precip was pronounced in the 00Z model runs as a Wed night-Thursday surface trough that rolls out of the Northern Rockies, with a Pac-NW low pressure pedigree. NAM picks up the moisture transport ahead of the trough. Meanwhile, an upper-level low will develop off the coast of CA through the week, and may split the jet enough to either force out another piece of energy across the Great Basin...timing of this feature and "my guess" is iffy this far out, but I don't think we can discount the possible impact...especially since both the NAM and GFS40 gave it great prominence. Right now, other forecast office trends have been to write in a clipper over the weekend that would trump any energy pushing across the Rockies. So for now, the mid-week forecast will remain categorical, and we will hold off on weekend weather guessing for now.
MLKJr Day...Partly cloudy turns Sunny throughout the day. High 12. North winds 10-15 mph. Overnight, partly cloudy, Low -5.
Tuesday...Sunny, cold. High 14. Northwest wind 5-10mph. Overnight low 5.
Wednesday...Partly cloudy, High 22. ENE wind 5-10mph. Overnight low 10.
Thursday...Mostly cloudy, High 25. SE wind 5-13. 30% chc of snow showers.