Update (3/21) - (3:30am) In keeping with the forecast yesterday, snow flurries and squalls are spotting up in the tri-state area at present. This is not captured well on the models (and often rarely is) -- here's the scene:
|NAM - Early Thursday||RadSat Product - Early Thursday|
That model is only a few hours beyond its initialization, and it's already wrong. It was practically wrong from the start. The GFS suffers from the same problem. What happens here is a gift to the 'old-school' meteorologists, because to forecast snowfall here is to understand longstanding weather patterns and a more macro view of meteorology. At the surface, temperatures are in the mid 20s (~ -4C), at 850mb, they are -12C, at 500mb they are -33C. This shows a "precipitous" (pardon the pun) drop in temperature with height. In meteorology, we call this a "lapse rate", and it evokes a generally unstable atmosphere. Any little perturbation would set things off, squeezing out moisture from the clouds. On a different day, this may not amount to anything-- even drizzle that evaporates before hitting the ground (called "virga"). But in cold snow scenarios, you can get as much as a 50:1 ratio of snow to liquid equivalent. Meaning, just 0.01" of liquid precipitation (practically nothing) can put out a 1/2" of dry snow on the ground.
When conditions are ripe for this on a regional scale, it's a good idea for meteorologists to set aside what the super-uber-high-resolution new-fangled models are telling you, and simply go with the old-school :-)
We'll be tracking the possibility for each wave of flurries to drop a stray dusting to as much as that dry 1" of snow (and of course a little extra in the mountains), though in between episodes given the dry air don't be surprised to wander right back into sunshine. Typical lake effect pattern; you just wish you had left it behind when it was actually winter.
Happy Wednesday everyone-- and happy first day of spring!
Spring technically is called the "Vernal Equinox" and it represents the moment the Sun's direct rays shine directly over the Equator on its way up toward the northern latitudes (Tropic of Cancer).
Of course, if the Earth didn't have a tilted axis, all of this would be moot.
It's just too bad the temperatures aren't corresponding to the change of seasons. Case in point: 2012-- Here's what our temperatures were just a year ago:
March 19th: 84°
March 20th: 86°
March 21st: 87°
March 22nd: 85°
March 23rd: 81°
Check out the 7-Day graphic below... not even close, right?
In fact, we'll be in a regime where the cold stays in place and the windflow brings lake-borne moisture across the tri-state. Each day will have a section of it where we'll be tracking flurries. Here's what the NAM has been continuing to show these past few days:
|NAM - Precipitation Type - Wednesday Afternoon||NAM - Precipitation Type - Thursday Afternoon|
Today appears to be more widespread in coverage, compared to Thursday where it's deemed to be mostly the traditional upslope. Nevertheless a sharp contrast to last year.
Things stay decidedly more winter-like right through the weekend as well. We are tracking another storm system headed in, and the GFS/Euro has continued to paint this one as an eventual snow-maker for our area. Here's the GFS on it:
|GFS - Sunday Evening||GFS - Monday Morning|
It's another one of those systems that spawn a new storm on the other side of the mountains and the inital parent system fills in. Initially, the track is more of a rain-maker, but once the coastal low takes over colder air wraps around the back and we'll be watching for some flakes. I wouldn't start thinking about accumulations just yet-- it's still way too far out for this one. But, the timing is a little inconvenient: the first AM commute following the end of many Spring Breaks...
|Regional Radar/Satellite with Warnings Tracking||
From the Storm Prediction Center (below): Click For a Larger Image
|Activity Overview||Storm Outlook||Watches||Potential Watches||Storm Reports|
|Temperatures||HD Doppler Radar||Estimated Rainfall||Active Warnings|
|Click For Larger||Click For Interactive Radar||Click For Larger||Click For Larger|
Have a great day everyone!