Snow stays west: Lighter metro totals?

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.

Latest NAM model shifts snow band west of Twin Cities.

GFS lays big snow range across metro with lighter amounts NE 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.

PH

8:30am post:

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.

NAM & GFS cranking out between 5.7" & 8.7" totals for the metro.

NAM paints 3" to 6" totals in the western half of the metro, with a sharp cutoff in the northeast metro.

GFS bring the "mother lode" of 3' to 6" right into the Twin Cities, and suggest some 8" totals just NW.

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!

PH

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.

The System: Another hybrid Pacific/Clipper tracking toward Minnesota from the Pacific Northwest. This is the same storm that produced a rare possibly EF2 tornado in Aumsville,Oregon Tuesday.

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.

NAM model with snow:water ratio, liquid total of .33" and forecast snowfall of 5.7" for MSP Airport highlighted.

(Click on images to enlarge)

-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.

NAM model lays out heavy snow band just southwest of the metro by Thursday.

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**

Latest NAM & GFS models crank out 5.7" & 4.2" totals for MSP Airport by noon Thursday.

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.

PH