Saturday, December 8, 2012

December 9: Snow Drought Over for Twin Cities (5-10" expected, a foot not out of the question)


A Real Snow Storm? "Yeah - right. We've heard that before." You have every right to be skeptical. I was too. After last winter's snowy disappointment, where 2" morphed into Breaking News! I tried to be extra-cautious with this snow event, because I didn't want to get my hopes up...or yours. But during the day Saturday computer models became more and more impressive, and that heavy band of snow forecast to set up from Alexandria to Brainerd to Duluth? It now looks like it's going to set up directly over the Twin Cities Sunday. Snow may not taper until late afternoon or evening. By then we should be digging out from 5-10" of snow, the biggest snowfall in 2 years. A real snowstorm. Imagine that.

* heaviest snow: morning into early afternoon Sunday. Snow may fall at the rate of 1" hour during the AM hours.

* temperatures near freezing morning hours: meaning heavy, wet, slushy snow. Temperatures drop into the 20s by afternoon, meaning a more powdery snow by late afternoon, more prone to blowing/drifting.

* Blizzard Warnings posted for parts of central and west central Minnesota. Never tell a Minnesotan not to travel, but I would seriously think twice on Sunday, especially heading west on 7 or 12. White-out conditions are possible as close to the metro as Mankato, Willmar and Glencoe.


Looks Like Snow

Snow. Noun. "Atmospheric water vapor frozen into ice crystals and falling in light white flakes or lying on the ground as a white layer."

Maybe absence really does make the heart grow fonder. At least it's Sunday, when travel is optional for many. Kids of all ages will look longingly out the window. Expect 5-10", definitely enough to shovel and plow, and fashion into formidable snowballs.

Snow gets a bad rap; a source of traffic snarls and broken hips. But snow is democratic and equal opportunity. That, and my nasty-looking lawn just got an upgrade.

Go slow out there; snow tapers by evening; the axis of heaviest snowfall forecast to set up from Willmar into the Twin Cities, the most snow from a single storm since December, 2010.

Cold winds kicking in behind the storm may create blizzard conditions as close as Willmar & Mankato. Better to wax the skis and exercise a snowmobile.

Welcome to the first inch or more of snow (in one day) in the Twin Cities since February 29. Chicago has gone 280 days without measurable snow, a record 279 days at Milwaukee.

More accumulating snow may fall next Saturday; no big thaws the next 2 weeks. Yes, we will have a white Christmas after all.

The last 2 weeks have reminded me to take nothing for granted. See the beauty in every one and everything.

Even a (rare) MSP snowfall.

00z NAM Numbers. I've been falling off my couch for the last 2 hours. The latest NAM guidance prints out .99" liquid; with a 10/1 snow/rain ratio that equates to 8-10" of snow. I know, impossible. But the prospect of a real storm just went up. Way up.

Gathering Storm Clouds. GR:earth shows a developing area of low pressure near Pierre, destined to track into central Minnesota by Sunday morning, pushing a shield of heavy, accumulating snow (and some ice) into Minnesota later tonight. Plan on a very snowy start Sunday morning.

Blizzard Warnings Expanded Closer to Metro. Winter Storm Warnings are posted for much of the metro, snow expected to get heavier the farther north you go. Winter Weather Advisories are in effect for the south metro. NWS has issued Blizzard Warnings for far west central and central Minnesota for tomorrow. Details:

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
336 PM CST SAT DEC 8 2012

...MAJOR WINTER STORM BEARING DOWN ON THE UPPER MIDWEST TONIGHT
THROUGH SUNDAY EVENING...
...BLIZZARD CONDITIONS EXPECTED ACROSS WESTERN MINNESOTA SUNDAY
AFTERNOON AND EVENING...

.A POWERFUL WINTER STORM CONTINUES TO ORGANIZE ACROSS THE DAKOTAS
AND WILL BEGIN AFFECTING WESTERN MINNESOTA THIS EVENING...AND
EASTERN MINNESOTA AND WESTERN WISCONSIN AFTER MIDNIGHT. LOW
PRESSURE WILL TRACK FROM ABOUT NEW ULM TO ROCHESTER ON SUNDAY
WHICH IS A LITTLE FURTHER SOUTH THAN EARLIER ANTICIPATED. MODERATE
TO HEAVY SNOW CAN BE EXPECTED AHEAD AND NORTH OF THIS LOW TRACK
TONIGHT AND SUNDAY.

BECAUSE COMPUTER MODELS HAVE SHIFTED SOUTH WITH THE TRACK OF THE
LOW...WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES HAVE
ALSO SHIFTED SOUTH. WINTER STORM WARNINGS ARE NOW IN EFFECT NORTH
OF A LINE FROM REDWOOD FALLS...TO RED WING MINNESOTA...AND EAU
CLAIRE WISCONSIN TONIGHT THROUGH SUNDAY EVENING. TOTAL
ACCUMULATIONS WILL RANGE FROM 5 TO 9 INCHES...WITH THE HEAVIEST
TOTALS NORTHEAST OF INTERSTATE 94.

WINTER WEATHER ADVISORIES HAVE BEEN ISSUED SOUTH OF THE WINTER
STORM WARNING DOWN TO THE IOWA BORDER TONIGHT THROUGH SUNDAY
EVENING. TOTAL ACCUMULATIONS HERE WILL RANGE FROM 3 TO 5 INCHES.

BEHIND THE LOW PRESSURE SYSTEM...SUSTAINED NORTHWEST WINDS OF 25
TO 35 MPH ARE EXPECTED OVER WESTERN MINNESOTA SUNDAY AFTERNOON
BEFORE TAPERING OFF GRADUALLY SUNDAY EVENING. SOME GUSTS MAY
EXCEED 40 TO 45 MPH. CONSIDERABLE BLOWING AND DRIFTING SNOW WILL
RESULT IN WHITEOUT CONDITIONS MAKING TRAVEL NEARLY IMPOSSIBLE BY
SUNDAY AFTERNOON. THEREFORE...A BLIZZARD WARNING WILL REPLACE THE
WINTER STORM WARNING FROM 11 AM SUNDAY THROUGH MIDNIGHT SUNDAY NIGHT
WEST OF A LINE FROM MANKATO TO ALEXANDRIA. AREAS OF BLOWING AND
DRIFTING SNOW ARE ALSO EXPECTED FURTHER EAST...BUT LIGHTER WINDS
PRECLUDE THE ISSUANCE OF A BLIZZARD WARNING AT THIS TIME.

TEMPERATURES WILL PLUMMET BEHIND THE SYSTEM TO WELL BELOW ZERO
LATE SUNDAY NIGHT OVER WESTERN MINNESOTA WITH WIND CHILL READINGS
AS LOW AS 20 TO 30 BELOW. DO NOT TRAVEL. SHOULD YOUR VEHICLE GET
STUCK...YOUR LIFE WILL BE AT RISK.


...WINTER WEATHER ADVISORY NOW IN EFFECT FROM 6 PM THIS EVENING
TO 11 AM CST SUNDAY...
...BLIZZARD WARNING IN EFFECT FROM 11 AM SUNDAY TO MIDNIGHT CST
SUNDAY NIGHT...

THE NATIONAL WEATHER SERVICE IN TWIN CITIES/CHANHASSEN HAS ISSUED
A BLIZZARD WARNING...WHICH IS IN EFFECT FROM 11 AM SUNDAY TO
MIDNIGHT CST SUNDAY NIGHT.

* TIMING...SNOW...HEAVY AT TIMES...WILL BEGIN EARLY THIS EVENING
  AND CONTINUE INTO SUNDAY MORNING. THE HEAVY SNOW WILL TAPER OFF
  SUNDAY AFTERNOON WITH A FEW SNOW SHOWERS EXPECTED THEREAFTER.
  THE WIND WILL THEN INCREASE FROM THE NORTHWEST WITH BLIZZARD
  CONDITIONS EXPECTED INTO SUNDAY EVENING.

* WINDS/VISIBILITY...NORTHWEST WINDS WILL INCREASE TO 25 TO 35 MPH
  WITH GUSTS AS HIGH AS 45 MPH SUNDAY AFTERNOON AND EVENING.
  CONSIDERABLE BLOWING AND DRIFTING SNOW WILL RESULT IN WHITEOUT
  CONDITIONS SUNDAY AFTERNOON AND EVENING WITH NEAR ZERO
  VISIBILITY.

* SNOW ACCUMULATIONS...4 TO 6 INCHES.

* TEMPERATURES...UPPER 20S EARLY ON SUNDAY WILL PLUMMET BEHIND THE
  SYSTEM INTO THE TEENS BY LATE SUNDAY AFTERNOON...AND ZERO TO 5
  BELOW LATE SUNDAY NIGHT. WIND CHILLS WILL FALL TO 20 TO 25 BELOW.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A BLIZZARD WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
EXPECTED OR OCCURRING. FALLING AND BLOWING SNOW WITH STRONG WINDS
AND POOR VISIBILITIES ARE LIKELY. THIS WILL LEAD TO WHITEOUT
CONDITIONS...MAKING TRAVEL EXTREMELY DANGEROUS. DO NOT TRAVEL. IF
YOU MUST TRAVEL...HAVE A WINTER SURVIVAL KIT WITH YOU. IF YOU GET
STRANDED...STAY WITH YOUR VEHICLE.

GFS Solution. Good grief - it may actually snow here. The GFS solution seems to agree with the WSI RPM model (below), showing the axis of heaviest snow setting up from Willmar and Glencoe into the Twin Cities and west central Wisconsin, a cool 5-10". My confidence level is fairly high that we'll pick up at least 5 or 6", with some 8-10" amounts likely in the metro.

WSI RPM Model. I saw this and nearly fell off my sofa. The 21z guidance from WSI's 12km model is a radical departure - showing the axis of moisture and deformation zone setting up from St. Cloud and Willmar into the Twin Cities metro into Sunday, some 8-10" amounts close to MSP? The 00z NAM confirms a big pile of snow by Sunday evening. It's a miracle.

Road Conditions. The University of Wisconsin has a useful site, showing where roads are icy vs. snow-covered vs. hazardous vs. "travel not advised". Best to check this URL before leaving the house this morning. The good news: It's not snowing on a Monday.

Go Kiss a Moose. This takes a lot of practice, by the way.