BLOG SONG:
"Blame" by Calvin Harris
INTRODUCTION:
Last week I made a few references to a potential storm Halloween Day into November 1st. The set-up is pretty intriguing - a western ridge with a northern and southern branch coming together for a possible phase which would develop a coastal storm, similar to the one we saw last week. However, the northern stream vort is pretty adamant on staying stationary over the Great Lakes circling around the PV lobe in southeastern Canada which keeps the phase with the southern stream energy to our north.
MODELS:
GFS:
GFS shows a potent storm develop that would bring some snow accumulations to parts of the interior northeast and northern New England. For the NYC Metro area, it would be just some light rain or snow showers.
The northern stream energy is strong and digs sharper into the northeast than the EURO model shows. This allows a phase with the southern s/w energy to occur sooner thus promoting precip. all the way to the coastline. You can see the ridge spike in the west-central US allowing for that northern stream energy, in combination with some positive heights over Greenland, to track into the northeast.
Once a phase occurs, an upper level low forms within the trough and snow is flying in the interior northeast thanks to the arctic air mass. Accumulations from northern and western NY to northern Maine range between 4 and 8 inches, more in higher elevations.
Here is a better look at the 500 mb pattern from the GFS. The NAO is actually negative and you can see the potency of the below normal heights over the northeast once the phase happens. Even though the coast sees little precipitation, if any, you can still expect our coldest temperatures of the season to occur on Saturday.
Here is a good look of the temps. expected for Saturday, November 1st. High's only in the 40's for the NYC Metro region. Check out the temps mid-day Saturday for areas north and west. Pretty cold!
EURO:
The EURO has the phase happen further north and virtually no precip. gets into the NYC Metro region. Honestly, the GFS and EURO have similar solutions. The GFS is just a little more amp'd up with the storm.
HALLOWEEN FORECAST:
At this point, I am expecting Halloween to be a pretty good day for trick-or-treaters (am I saying that right?). In the end, it will depend on the timing of when this phase occurs (I expect it to) and how quickly the cold air filters into the region. I do NOT think there will be much in the way of precipitation. If there is, it will likely to be some rain showers. Maybe snow showers for areas north and west of NYC. Temps. this day should be in the low to mid 50's but will quickly come crashing down after Midnight on Halloween. If guidance changes drastically during the week, I will be sure to let everyone know.
CONCLUSION:
There will be a phase due to the ridge in the west, the blocking over Greenland, and the slow progress of the cold front (which will move over us this Wednesday) to move out of here allowing the southern stream to slow down a bit instead of escaping out to sea. However, the phase will happen too late for the coastline since the northern stream is more of an Upper Level Vort that does not dig into the northeast, rather meander around the Great Lakes. The interior northeast and northern New England should see minor snow accumulations out of it. Possibly moderate accumulations in higher elevations.
NOVEMBER OUTLOOK:
It should be out sometime this week
WINTER OUTLOOK:
Still expecting a release date on Monday, November 17th. Everything is progressing as expected so far with regards to the snow cover over the Northern Hemisphere and the development of El Nino.
LINKS:
NJ Strong Weather Forum: http://www.njstrongweatherforum.com/
NJ Strong FB Page: https://www.facebook.com/njstrongwx?ref=hl
NJ Strong Twitter: https://twitter.com/nj_strong_wx
USAWx Forum: http://usa-wx.com/
Have a great night
Francesco Paparatto
