Middle Atlantic Winter Watch: Friday 2/22/13.
byon 02-16-2013 at 12:58 PM (529 Views)
Saturday Confirmation: RAIN/WARM
As the GFS wanted for over a week now, here's the warmth. Even more than it ever predicted. Curious as well since the low is further out to sea than expected...but that inland low is so strong and spring like - it isolated the surface coastal storm from grabbing any cold Canadian air.
As has been modeled for 7 days...no surprise twist. Rain is the forecast.
Of interest is Mt Holly, who always lags way behind - or never bothers with a snow map release, has chosen to make one for the event. Why?
Wednesday 2/20 Update
Good morning all. As has been modeled virtually the same for about five days now...any little hope for Friday in the form of a true snow storm should be gone.
GFS certainly slowed down however....seems to be about a day behind the NWS local forecast products.
Monday 2/18 Update
I'll just let the pictures do the talking for the most part here....
Was always to be a warm storm...but we still cling to hope the coastal feature takes over and pulls in cold air. On these maps you can see it's close - but only to the tune of maybe ending as snow for some...but meager if any accumulations as a result.
Sunday 2/17 Update
Well..Friday looks even worse....for snow lovers.
The parent low is even strong and now the GFS mirrors the ECMWF on it's trajectory North East into the Great Lakes/Upper Plains!
Look at what it does to the temperature profiles for the East Coast.
It's a bust...it's been forecast as a bust and modeled as a bust for two-three days. Not sure why that would change.
There is the potential for a system on Friday the 22nd to deliver snow to the Middle Atlantic region.
As always with models this far out you never take them literally in detail you simply take them as a hint that a disturbance will be in the region around that time.
At present the National Weather Service is calling for rain in the region and based on model rendering this would be appropriate.
What to watch: The GFS model brings a low in from the Central Plains, sends it decaying into the upper Ohio Valley, while developing a strong new surface low in the southern Middle Atlantic. What we are looking for is whether or not the new surface reflection quickly becomes dominant causing an earlier decay of the older inland surface feature.
Whenever the inland feature remains strong, clinging to life if you will, this isolates the new coastal surface low from the cold air...and it acts as a conduit for warm air to come north and west and flood inland - thus keeping rain in the region.
However, if and when the surface low becomes quickly dominant, and the inland low decays quickly, you have the reverse take place and the new surface feature pulls cold air down from the north, deepens, and floods the region with colder air and thus a changeover to snow.
What we will look for in future model runs is how quickly the surface low forms, how quickly it intensifies frame by frame --- while at the same time noting if/how quickly the inland primary low decays. If the inland low continues to remain relatively strong as it is shown in the above image...you'll get rain possibly ending as snow at the end.
If we begin to see more evidence of a stronger new surface low and more quickly decaying primary - we can begin to assume a quicker changeover to snow, and perhaps a significant system for the middle atlantic may take shape.
More updates as is warranted...but we will give this a couple of days to stew before doing so.
In light of recent model and therefore forecasting volitility we will remain conservative and in mere analysis mode until something concrete presents itself. Only then will we begin to guess.