Winter 2013-14 Thread — Northern Hemisphere (snowfall, warm, temp, Chicago)

[chicagogeorge]

Another look at the first half of February

[Cambium]

Matt Noyes:

"Current propane shortage nationwide has resulted in energy emergency declaration for two dozen states."


Current Temps across the Lower 48. Freezing line pushing southwards so is that 0°F line

[chicagogeorge]

[nei]

Originally Posted by Cambium

Look at the 850s and 925s. Layer above the surface is/was above freezing but as the front moves through everything will drop below and support snow if moisture still around.

SPC Hourly Mesoscale Analysis

Here was the 925mb temps at 7am. Warm air aloft pushing northward because of a strong southwest wind ahead of the front

Some Surface areas stayed below freezing hence the ice.

Thanks. Here's what my forecast discussion said:

NUMEROUS AREAS OF FREEZING RAIN DEVELOPED THIS MORNING IN THE
INTERIOR ASSOCD WITH SHALLOW WARM LAYER BELOW 850 MB COUPLED WITH
COLD AIR HANGING AT THE SURFACE. LOW LEVEL COLD LAYER HAS MIXED
OUT WITH TEMPS ABOVE FREEZING ACROSS MUCH OF THE REGION AS SOUTH
WINDS INCREASING...AND REMAINING SUBFREEZING TEMPS IN THE
MERRIMACK VALLEY OF NH SHOULD BRIEFLY RISE ABOVE FREEZING BY
MIDDAY.

this sounds nasty:

VERY MILD TEMPS NEARING 50 IN THE COASTAL PLAIN WILL
FALL THROUGH THE 30S THIS AFTERNOON AFTER FROPA WITH SOME UPPER
20S ALONG THE I95 CORRIDOR BY DAYS END. THERE MAY BE POCKETS OF
BLACK ICE DEVELOPING LATE TODAY IN THE COASTAL PLAIN AS TEMPS
PLUMMET...ALTHOUGH WEST WIND IS A DRYING WIND WHICH SHOULD LIMIT
AREAL COVERAGE OF ANY ICE ON THE ROADS.

850 mb temperatures will bottom out at -20 to -22°C


TUESDAY NIGHT THROUGH WEDNESDAY...
ANOTHER SURGE OF ARCTIC AIR WORKS IN DURING THIS TIMEFRAME AS
A LARGE HIGH PRESSURE MOVES SOUTHEAST INTO THE MID ATLC STATES.
THE HEART OF ARCTIC AIR REMAINS JUST NORTH AND WEST OF OUR
REGION...BUT WE WILL STILL SEE SIGNIFICANTLY COLD TEMPERATURES AS
850 MB TEMPERATURES DROP TO -20C TO -22C TUESDAY.

the milding:

HIGH PRESSURE RIDGE ORIENTS NE-SW FROM NEW ENGLAND TO THE GULF OF
MEXICO. NOTING W-NW WINDS BACK TO SW DURING THE DAY. 850 MB
TEMPERATURES MODERATE SOMEWHAT...BUT REMAIN AROUND THE -8C TO
-10C RANGE. EXPECT HIGHS TO BE ABOUT 5 TO 10 DEGS HIGHER THAN
WEDNESDAY...BUT WILL STILL RUN 5 TO 10 DEGS BELOW SEASONAL NORMS.

They don't seem too certain about the weekend yet

[Cambium]

First time since January 20th most of the region is above normal with the Max temp today.

[NorthernMoose]

Round 2 for the Alberta Clippers coming through. I give up on plowing until this is done. Not worth it. First one is looking out my back door towards the neighbor. You can see his flag standing straight out it's so windy and then of course looking out the front window at the usual mess. It's -1 F with the wind chill at -15 F.

[Cambium]

Originally Posted by nei

Thanks. Here's what my forecast discussion said:

NUMEROUS AREAS OF FREEZING RAIN DEVELOPED THIS MORNING IN THE
INTERIOR ASSOCD WITH SHALLOW WARM LAYER BELOW 850 MB COUPLED WITH
COLD AIR HANGING AT THE SURFACE. LOW LEVEL COLD LAYER HAS MIXED
OUT WITH TEMPS ABOVE FREEZING ACROSS MUCH OF THE REGION AS SOUTH
WINDS INCREASING...AND REMAINING SUBFREEZING TEMPS IN THE
MERRIMACK VALLEY OF NH SHOULD BRIEFLY RISE ABOVE FREEZING BY
MIDDAY.

this sounds nasty:


850 mb temperatures will bottom out at -20 to -22°C



They don't seem too certain about the weekend yet

Thanks. Yeah, the black ice tonight is from the arctic front with quick temp drops.

Temps will naturally moderate after mid week. Just imagine if we had true blocking?? This arctic air (if timed right with blocking) would be stuck over us...or someone else.

Weekend still too far for details but should be below normal still.

Nice mention of that warm air aloft I mentioned. "Shallow" was key word. Wasn't a big warm up but a small layer above us that melted any precip falling which turned to ice for the surfaces that stayed below freezing. I had light liquid drizzle here this morning. 35F

Those 850s bottoming at -20C is well below normal for that level even this time of year. Hence the surface reflecting it.

[nei]

where would the blocking air mass need to be for true blocking?

[chicagogeorge]

10 day 500 mb.... If you like your Alaskan Ridge you can keep it!






LOL.... Latest CFSv2 for February... Trolling the winter haters

[Cambium]

Originally Posted by chicagogeorge

10 day 500 mb.... If you like your Alaskan Ridge you can keep it!

. How boring is that, sunny and warm... and in winter to boot. LOL. They deserve it I guess, nice to have a break from True winter. We had our fair share of a ridge here past few winters.

Originally Posted by nei

where would the blocking air mass need to be for true blocking?

I like it near Greenland and even into Canada a bit to stop the arctic air from flowing out.


Current 500mb



Judging by this, looks like Alaska going to get a break from the warmth thanks to that Upper Low moving in and pushing a trough down. Haven't looked into it so just using this current setup to mention it.

We havent had real blocking since October. http://www.cpc.ncep.noaa.gov/product.../pna/nao.shtml