Updraft: January 17, 2013 Archive

Friday Thaw; Window rattling Arctic front Saturday; NWS new "warning" language?

Posted at 8:07 AM on January 17, 2013 by Paul Huttner (4 Comments)

36F high temp at MSP Airport at 12:12pm Wednesday

7F low at MSP so far Thursday

Arctic sideswipe - brief glancing blow of arctic air today

Friday thaw milder Pacific air returns briefly Friday as temps crack the thawing point

Siberian Express rolls across Minnesota Saturday as temps plunge toward zero and northwest winds gust over 30 mph

Life on the temperature roller coaster:

We're getting used to this in Minnesota these days. Rising temps before sunrise? Falling temps during the "warmest" part of the afternoon? It's what meteorologists call "advection."

As Arctic and Pacific air masses battle for control of Minnesota through Saturday, expect more unusual temp swings at odd times of day.

Thursday will feel like Old Man Winter. Friday may tease "hints of March" by late afternoon. Saturday will leave no doubt that it is still mid-January.

Arctic Invasion: Still on track

Okay, so it won't get that cold in Minnesota next week...but you have to appreciate the youthful sense of fun when temps drop at UAF.

We shouldn't be surprised that a sub-zero arctic outbreak is on the way to Minnesota in mid-January. What's surprising is that we have avoided a sub-zero daytime high at MSP Airport for a record 4 year stretch.

It's going to get very cold starting on Saturday night...and lasting into most of next week. The only question appears to be...how cold?

Image: NOAA GFS MOS output via SUNY-Albany

The magnitude of arctic outbreaks is often hard to gauge before the fact. Models generally have trouble with precision on extreme events...those that stray far from "climatology."

Arctic air is sometimes underestimated...and usually reluctant to leave as fast as the models would like once the heavy, dense arctic air is in place.

The lack of deep snow cover across Minnesota is one factor working against prolonged, extreme cold.

The Twin Cities Urban Heat Island...with MSP Airport on the southern end of a light northwest flow on cold nights...is effective at keeping temps in the central urban core and MSP Airport as much as 10 to 15 degrees warmer than the outlying suburbs/exurbs like Lakeville and Glencoe.

-10F at MSP Airport? -15F? We'll probably bottom out somewhere in between those two numbers Monday or Tuesday morning.

It's increasingly rare for us to hit -20F in the inner metro core. The last time we saw -20F was 4 years ago in 2009 on January 16th when the mercury plunged to a respectable -22F.

As of now...I don't think we'll get that cold this time.

Cue applause.

Word games - NWS looking at options for more effectively communicating weather warnings

It was riveting to sit at the Hurricane Sandy Town Hall and listen to National Hurricane Center Rick Knabb and Weather Channel Hurricane Specialist Bryan Norcross talk about "messaging" with Hurricane Sandy.

As the ferocious and devastating hurricane approached the Jersey Coast, NHC was wrestling with a decision. Do we drop "Hurricane Warnings" as Sandy hits shore and become "post tropical?"

There are debates about what kind of storm Sandy was "meteorologically speaking" as she slammed into New York and New Jersey. But there is no questions that the effects were those of a hurricane.

I've gone on record as saying that after an excellent, life saving forecast and warning scenario in the days leading up to Sandy, I think NHC dropped the ball on communication and messaging by dropping "hurricane warnings" as Sandy roared ashore.

Everyone knows what a "hurricane warning" means. Few have ever heard of a "post tropical cyclone."

It sounds like a broken beach amusement park ride...and certainly doesn't convey an immediate sense of urgency... or the imminent emergency conditions Sandy was about to unleash on the most densely populated coastline in the USA.

I was encouraged to hear at the meeting that NHC has a proposal that will allow them to retain "hurricane warnings" for future storms as they come ashore...even if they are in transition to "post tropical" or "hybrid" systems.

Now NWS is looking at "simplifying" terminology for all weather warnings, and Minnesota is in the Guinea Pig zone for this test.

My initial read?

The term "Warning" has credibility and conveys a sense of action, and should be retained.

I'll need some time to take a look at the rest of the proposals here. But I thought this would be a great opportunity for you as astute Updraft readers to take a look at the proposed changes here and give your opinion to NWS.

What do you think?

PH

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(4 Comments)

Overnight Clipper; Friday thaw; Flash freeze to deep freeze Weekend

Posted at 6:13 PM on January 17, 2013 by Paul Huttner

Alberta Clipper sails through Minnesota early Friday

Light snow likely from the metro north

Coating to 1"+ in the metro by early Friday AM

1" to 3" possible in central & northern Minnesota including St. Cloud, Brainerd, Iron Range, Duluth, International Falls, Ely & North Shore.

40F Friday? 40 possible in metro Friday as warmer air gushes in from snow free areas to the south

Flash Freeze Saturday as season's coldest arctic front plows through

Deep Freeze Sunday as sub-zero temps invade Minnesota

Bottoming out at -17F by Monday morning in the metro? (Latest GFS output)

40+ hours below zero in the metro? (Sunday evening to Tuesday noon?)

Moderation next week temps in the 20s (above zero) by Thursday

Signs of snow?? Snow chances on the horizon next Thursday & again Sunday-Monday Jan 27th & 28th?

Lake-Effect Arctic blast will produce prolific "lake-effect" snows downwind from the Great Lakes this weekend

Charlie Brown Thaw:

It's almost like a cruel hoax.

Like when Charlie Brown tries to kick the football...and Lucy keeps pulling it out at the last second.

The mild air wins briefly Friday...almost as if to tease us with how spring could feel...beofre the advancing arctic front charges in Saturday to pull the rug swiftly and decisively out from under any sustained warm up.

Minnesota sits on the boundary of Pacific and Arctic air masses through Saturday.

To the south, temperatures reached the balmy 50F mark in eastern Nebraska Thursday with 40F into northwest Iowa. To the north, temps of -25F are lurking...just waiting to pounce on Minnesota this weekend.

Image: University of Illinois

Temps may make the 40F mark in the metro and I wouldn't be shocked to see a 50F reading along the Iowa border Friday PM.

Friday's incoming milder Pacific air is getting a few degrees of "enhanced warming" as sun warms bare ground over snow free areas of Nebraska and Iowa.

Enjoy Friday's thaw.

Weekend: Flash freeze to deep freeze

My wife Amber got on a plane today to Tucson. Good timing. She evacuated just in time to avoid what are likely the coldest days of this winter.

Saturday's arctic front looks to be the coldest in 4 years.

This will be one of those old fashioned, window rattling cold fronts. You'll know it when it arrives early Saturday up north...and Saturday PM & evening in the metro.

Flash Freeze: Saturday night's temp crash will be dramatic. Depending on which model solution you choose, temps will fall from near 30F at noon Saturday... to around -5F by early Sunday AM.

Image: Iowa State University

Bottoming Out: Again, it's a choice of model perspective.

I have little doubt temps will reach -30F in parts northern Minnesota by Monday morning.

My best read on the magnitude of this arctic shot is the Twin Cities looks to bottom out Sunday, Monday & Tuesday morning somewhere between -10F and -18F.

Image: NOAA GFS MOS via SUNY-Albany

Twin Cities suburbs like Lakeville and Waconia and Ham Lake will likely see -20F or colder. With our changing climate and urbanization, it's getting increasingly hard for the inner metro core to reach -20F.

Chill Factor:

Wind will be a factor, especially Sunday. With sub zero temps; any breeze can drive wind chills into the danger zone.

-45F wind chill in Grand Forks and -42F in most of northern Minnesota? That's not just respectable...but dangerous chill levels. We're used to cold around these parts...but late Saturday night through Wednesday will be one of the few periods in Minnesota where we can truly call the weather "life-threatening" if you're caught outside for any prolonged period.

"Black Ice" (water vapor from car exhaust freezing instantly on roads) may work it's way back into our winter weather lexicon , and could be a factor for our Monday AM commute.

Boy Scout motto on this one...."Be Prepared."

Moderation:

It looks like the cold wave will ease starting next Wednesday. Temps should recover into the 20s by Thursday.

There are signs that a low pressure system may develop Thursday and bring some snow to Minnesota.

GFS model next Thursday

How much? Way too early to say...but it looks like the first decent chance of something "plowable" in quite some time.

The models seem to be hinting at another potential system Sunday & Monday January 27th & 28th.

The "snow drought" this year is not as deep as last winter, and it has to snow sooner or later.

Right?

Lake-Effect Snow Machine Kicks In:

One amazing aspect of these bitter arctic outbreaks is the prolific lake-effect snow totals that are generated downwind from the Great lakes.

Check out Thursday's NASA MODIS Terra image looking at Lake Superior. You can clearly see the distinct plumes of lake effect snow rolling downwind into Michigan's Upper Peninsula. Amazingly....you can even see some lake-effect snow plumes generated from Lake Nippigon!

Image: NASA MODIS via UW Mad-Town

As colder air blows over relatively warm waters, heat and energy are released into the bitter air above...and wrung out in these intense, focused lake-effect snow bands.

Check out the forecast for some prolific, 1 to 2 foot snowfall totals in the next 5 days.

Image: NOAA GFS 5-day snowfall via wxcaster.com

Want really deep snow? Book a vacation to northern Wisconsin or Michigan's U.P. in the lake-effect Snow Belt after this arctic outbreak.

PH