first major snowstorm?

[Dan Cook]

Looking at DVN's area discussion:

AFTER A QUIET DAY WEDNESDAY...SIGNALS FROM THE GLOBAL MODELS SUGGEST
A SIGNIFICANT SYSTEM TO AFFECT THE REGION LATE WEDNESDAY NIGHT
THROUGH THURSDAY NIGHT. IF THIS TREND CONTINUES...A WHITE CHRISTMAS
IS VERY PROBABLE.

oh I hope so.

 

[Caleb Lawrence]

I saw something that looked odd on the GFS. I'm with you; any type of weather activity would be welcomed...let it snow, let it snow, let it snow.

 

[Andrew Pritchard]

Its definetly going to be cold from the looks of it. The first arctic blast coming on Sunday and Monday, with a small warming trend into Wednesday, and then, another more widespread arctic blast following that.

 

[Tony Laubach]

NWS here in Denver is saying the same things for next week... possibly major arctic air coming down for X-mas. They're not mentioning any major snow event; just colder air. Worth keeping an eye on.

AS THINGS SLIDE INTO MIDWEEK THE GFS AND DGEX CARVE OUT A SUBSTANTIAL TROUGH OVER MUCH OF THE COUNTRY WHICH COULD LEAD TO A PRETTY DECENT BLAST OF COLD AIR HEADING OUR WAY...PERHAPS AS EARLY AS WEDNESDAY. HOWEVER...THE ECMWF MODEL IS QUITE A BIT DIFFERENT...DUMPING THE COLD AIR AND DEVELOPING THE TROUGH QUITE A BIT FURTHER EAST MORE QUICKLY. INTERESTINGLY...BY 23/00Z THE MSL PRESSURE IS SOME 15-20 MB HIGHER OVER MONTANA IN THE DGEX/GFS THAN IN THE ECMWF WITH A GFS 1050 MB HIGH POISED OVER NORTHWEST ALBERTA. CHRISTMAS COULD BE A COLD ONE IF THAT SOLUTION PANS OUT.

THERE ARE HINTS IN THE LONGER RANGE FORECASTS SUGGESTING THAT A STRONG PUSH OF COLD ARCTIC AIR MAY INVADE THE OUTLOOK AREA BY THE MIDDLE OF NEXT WEEK. HOWEVER ...IT IS TOO EARLY TO SPELL OUT ANY DETAILS OF THIS EVENT.

 

[Robert Dewey]

Usually when an arctic outbreak occurs, and mid level energy is diving into the west, the combination of a tight baroclinic zone and that little bit of energy can spark up a pretty good storm.

Still, at 180 hours, the GFS is showing a decent storm, but things would have to come together just right (i.e. energy has to drop at about the same time the arctic front is moving through, etc.).

 

[Mickey Ptak]

GFS (as of the 12Z run) definitely picks up the push of artic air even as far south as southern Texas. could be a very cold Christmas for us southern plainer's as well. It would be nice to get a little snow here in OKC for the holiday, but as of now that looks very slim.

Anyone know when the last time OKC had snow on Christmas?

Mick

 

[Lance Maxwell]

I believe it was either last year or two years ago that OKC got 3 inches on Christmas Eve.

 

[Gabe Garfield]

The 00z run of the GFS last night was incredible!!!! I've never seen GFS forecast sub-zero temps for Oklahoma. All extended models agree that at least some portion of the arctic air mass will make its way into the southern and central plains (and definitely into the eastern United States). It looks like a lot of folks could be seeing a white Christmas this year!

Gabe

 

[Andrew Pritchard]

Oh goodie. It's supposed to be 6 degrees Sunday night! W00t! W00t!

Thats the NWS's take on it...i think we'll get a few degrees colder, possibly going below 0.

 

[Andy Wehrle]

at least some portion of the arctic air mass will make its way into the southern and central plains (and definitely into the eastern United States). It looks like a lot of folks could be seeing a white Christmas this year!

Remember, cold doesn't necessarily mean snow. The colder the air is, the less moisture it can hold. The less moisture, the less likely a significant snowfall.

 

[Robert Dewey]

at least some portion of the arctic air mass will make its way into the southern and central plains (and definitely into the eastern United States). It looks like a lot of folks could be seeing a white Christmas this year!

Remember, cold doesn't necessarily mean snow. The colder the air is, the less moisture it can hold. The less moisture, the less likely a significant snowfall.

The best range of temperatures for heavy snowfall seems to be around 20-28F. At those temperatures, the snow to liquid ratio is high, so even a little QPF can go a long way. Temps of 10F or lower, as you said, make heavy snow unlikely (unless it's lake effect).

 

[Gabe Garfield]

Remember, cold doesn't necessarily mean snow. The colder the air is, the less moisture it can hold. The less moisture, the less likely a significant snowfall.

Actually, air doesn't "hold" water. Essentially, evaporation and condensation are in equilibrium with each other. When the temperature is high, more water can be evaporated from the free surface interface between air and water. This increases the mixing ratio of the air. The opposite is true for colder temperatures.

In addition to this, strong cold air advection in the eastern United States tends to create strong baroclinic (temperature gradients) zones near the warm waters just off the coast (due to the higher effective heat capacity of the water relative to the land). This in turn creates strong jet streams (and likewise vorticity maximums) which help create strong surface lows (and associated rising motion).

Also, the Great Lakes should be primed for lake effect snow because of the relatively warm waters and strong cold air advection. Assuming that vertical shear will be relatively weak at the trough axis, I see the western Great Lake states receiving heavy snow in the days around Christmas.

Gabe