Update 3:20 pm:
I said this was a tough storm to forecast...boy was that on the mark.
In a stunning (but not totally unexpected) turnaround, both the GFS and NAM forecast models have dropped predicted snowfall totals for the Twin Cities drastically.
The NAM has been the most erratic model...going from 7" to under an inch to 5.7" then back to ZERO in the span of 48 hours. At one point this morning, our two "most trusted" models...both of which handled last weekend's Domebuster extremely well...we're forecasting zero snow... and 8.7"!
Bad models....very bad models!
It looks like our "on again-off again" metro snow event is mostly "off again" for much of the central & east metro. The latest model runs and radar trends confirm that the bulk of the snow may linger just west of the Twin Cities for much of the event, with lighter totals for the Twin Cities.
I still expect 3" to 6" totals along a Alex-Willmar-Hutchinson-Northfield line....with lighter amounts in the west metro. It appears we may see just a dusting in the far east metro now. At this point a snow forecast of a coating to two inches seems like the most likely outcome...with lighter totals (just a dusting?) in the northeast metro.
We'll need to watch this one to see how far east the snow moves as it battles some drier air over the metro, but it looks like my original forecast of accumulating snow in the southwest metro and a rapid drop off in snow totals by the time you get to the NE metro may work after all.
Here we go again.
It's like somebody put a big weather target over Minnesota this year, and all weather systems are aiming right for us.
Our next wave of snow is crawling eastward through Minnesota today, as another shot of "Minnesota Powder" moves in.
The latest model runs are pushing the steadier snow just east...with the core right into the western Twin Cities metro. This forecast is actually tougher than the big weekend Domebuster beacuse of the sharp cutoff in snowfall on the east side of the system. There is a higher than average bust potential for this forecast!
Update: As if on cue...the new NAM model run in this morning has removed all snow from the forecast and now shows .00" precip! Arrrrghhh.
This is me tearing my hair out with this system. So do I believe the NAM (little or no snowfall?) or the GFS (8.7" snowfall?) or take the "split the difference" forecast. Stay tuned...the bust may be ready as the modles are back to discord with this weather system!@#*!^# So, you wanna be a weather forecaster huh?
Unless the system is effectively stalled to the west...it looks like another relatively long duration (18-24 hours) light snow event could add up to 3" to 6" for the Twin Cities (especially west metro) by Thursday afternoon.
It looks like the heaviest snow axis will run along and south of the I-94 corridor from Fargo through St. Cloud & Willmar into the western metro and south to Mankato & Owatonna & Waseca.
The overnight NAM & GFS runs are cranking out 5.7" and 8.7" of snow at MSP Airport by Thursday PM. I'll lean a little conservative with an overall 3" to 6" range for the metro...with the lesser amounts on the NE metro and the higher totals in the SW metro.
Check out some of the model data, which supports raising snowfall for the metro a bit.
Bottom line: Expect more snow to spread east into the metro late afternoon, and expand tonight. Thursday AM rush hour looks to be the slickest, with slippery roads in the metro.
Get ready for another shot of snow!
10pm Tuesday post:
"What we've got here is a failure to communicate." The classic line from the 1967 movie "Cool Hand Luke" perfectly described the forecast models Tuesday.
The forecast models we're not playing nice...but it appears we are closer to consensus. It's going to snow again in the Twin Cities, and it may be enough to shovel and plow in much of the metro.
With the evening model runs in tonight, here is my best shot at the forecast.
Here's the video from KGW TV in Portland.
Timing: It looks like snow will increase in west central Minnesota Thursday morning (Alexandria-Willmar-Mankato) and midday, then spread slowly east.
-Snow could begin to move into the Twin Cities metro from west to east between about 4pm and 7pm Wednesday evening.
-Snow should continue through Wednesday night until about noon or 3pm Thursday. (Total duration of about 18-24 hours?) It looks like the worst road conditions could be during Thursday AM rush hour.
Snowfall character & intensity: This snowfall could be a littler wetter at the onset of the storm (12:1 snow:water ratio)...then transition to another dry powdery snow (20:1) overnight into Thursday.
-Snowfall intensity should be considerably lighter than last weekend's "snow attack", when rates exceed 1" to 2" per hour. This should be a lighter snow, with rates between .2" and .5" per hour for most of the event.
Snowfall totals: This will be another efficient snowfall producer.
Heaviest snow band:
It appears the heaviest snow band will run along a NW to SE line...along and south of I-94 from Fargo-Alex-Willmar-Hutchinson-Northfield-Owatonna-Albert Lea.
It looks like 3" to 6"+ with some isolated 8" totals could fall in this area.
Twin Cities Metro:
It looks like there will be a big snowfall gradient from NE to SW across the metro (forecaster's nightmare), with a sharp cutoff with little or no snow just northeast of the Twin Cities. The southwest metro may fall within the eastern edge heavy snow band.
Northeast Metro: (Lino Lakes, Forest Lake, Stillwater) Coating to 2"
Central Metro: (Maple Grove-Minneapolis-St. Paul-Bloomington-Eagan)
2" to 5"
Southwest Metro: (Lake Minnetonka-Waconia-Shakopee) 3" to 6"
** Any shift in the track of the system to the east or west will increase/reduce snowfall amounts accordingly**
It looks like we're going to get ready to shovel again by Thursday. (Where will I put any more snow??)
Stay tuned as we tweak the system based on the morning model runs.
Weatherpacolypse 2010 continues!
Southwest mountain forests under attack as warming increases:
I spent 9 years working in Arizona. While I was there I watched (and reported on) over a million acres of high altitude forest go up in smoke in the past decade of drought and heat.
Researchers at the UA Tree Ring Lab (Yes, there is such a place and I have been there! It's actually under the UA football stadium!) presented papers this week that forecast the disappearance of large chunks of high altitude forest in the southwest due to climate change.
"More than half of the Southwest's high-altitude forests could be gone by mid-century, under a worst-case scenario for continuing drought outlined by other UA researchers in a series of papers published this week in the Proceedings of the National Academy of Sciences. The eight papers sound warnings about the effects of drought on the region's ultimate sustainability."
Many of Arizona's mountain forests get just enough rain, snow and coolness to survive in a marginal climate zone. Any shift toward hotter and drier climate has a huge impact, and can be a "tipping point" for the mountain biome.
The sad story here from azstarnet reporter Tom Beal.
The latest clipper to sail through Minnesota is delivering a glancing blow to the Twin Cities, and a harder punch to areas just south & west of the metro.
Persistent snow fell much of Wednesday PM & night west of the metro. Late Wednesday evening, a few totals are trickling in to the weather lab.
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1041 PM CST WED DEC 15 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
0600 PM SNOW GLENWOOD 45.65N 95.38W
12/15/2010 M1.0 INCH POPE MN CO-OP OBSERVER
0609 PM SNOW 2 N WILLMAR 45.15N 95.05W
12/15/2010 M1.0 INCH KANDIYOHI MN CO-OP OBSERVER
0817 PM SNOW ELLENDALE 43.87N 93.30W
12/15/2010 M1.5 INCH STEELE MN TRAINED SPOTTER
0910 PM SNOW LITCHFIELD 45.12N 94.53W
12/15/2010 M2.0 INCH MEEKER MN TRAINED SPOTTER
1035 PM SNOW MANKATO 44.17N 93.99W
12/15/2010 M2.0 INCH BLUE EARTH MN BROADCAST MEDIA
Thursday AM rush:
It looks like there will be some slick travel with falling snow favoring the western & southern metro. With temperatures in the teens, it won't take much snow for roads to slick up Thursday morning.
Winter weather advisories continue into Thursday morning. Plan for some extra travel time, especially in the southern & western metro.
Travel south & west of the Twin Cities will be slick, with higher snowfall accumulations in the 3" to 6" range. One consistent feature with this latest weather system is the predicted heavy snow axis, which still runs along an Alex-Willmar-Hutchinson-St. Peter-Northfield-Owatonna-Albert Lea line. Winter storm warnings remain in effect for these areas.
This has been an interesting (and confounding) storm to forecast for the metro...while the rest of the forecast for Minnesota is holding up well. The sharp cutoff from snow on the system's eastern edge literally means a 30 mile difference between no snow, and some 2-4 inch totals. That dividing line is right through the metro with this system.
Drier arctic air near the surface is literally eating away as moisture attempts to advance eastward.
Bottom line for this system...expect slick roads for AM rush in the southern & western metro...with snow accumulations of a coating or less (east metro) to 2" (southwest metro).
It looks like we may sneak in a few quiet days before we look for the next snowmaker which could move in on Monday.
Domebuster snowfall compressing on the ground.
Check out the photo of the small holiday light trees outside the weather lab. Notice the tree on the right? It was completely covered with snow after last weekend's storm. Now, a crown of snow remains stuck to the star on top, while the rest of the snowpack has compressed a good 2 to 3 inches.
This is a good example how a fresh fluffy powdery snow can compress after a few days. The crystals break down over time and compress. Who knew?