Cold & Dry This Week, with Arctic Air & Bitter Cold for Thursday into The Weekend. Flurries & Snow Showers For Tuesday and Thursday with Clippers.

Discussion: Monday 1/12/09
My Forecast:
Monday through Thursday for the Delaware Valley Region:

THE DEEP FREEZE IS ON THE WAY:
We're all heading into the DEEP FREEZE for a good 3 to 4 day period, which starts on Thursday and continues into the weekend. I see this week being Very Cold to Bitter Cold, but overall conditions will be DRY. Expect a couple of clipper systems for both Tuesday and Thursday, one with an Arctic front on Thursday, will both track overhead, or just to our north. In relation to snow that's a very BAD STORM TRACK for Us.

This time the cold air will be here and in place, but the main swath of snow always falls to the north of the center, with most clipper systems. Yes an Arctic front associated with Thursday's Clipper, moves through with a period of light snow or flurries on the south side of the system, but I see nothing more than a light accumulation at best for both Tuesday and Thursday's events. Both Systems will be rather weak and moisture starved as they cross the mountains.

This will leave only a threat for some flurries, snow showers, and possibly a period of light snow, that could leave a Coating to 1" for areas South of PHL. Further north into the Lehigh Valley, and into the NYC area, 1" to 3" can't be ruled out, especially on Thursday.

OUR ONLY HOPE FOR A SNOWSTORM IN THIS PATTERN:
In most cases for our region, when an Arctic air mass begins to retreat, this usually leaves a good opportunity for a snowstorm or significant snow event. A storm system will usually try to form on the SW side of the air mass, as Warm air advection increases, and there's some jet entrance into the retreating trough and cold air mass.

This type of setup is called WAA and Overrunning. Some of our best snow events, apart from coastal storms, have been from Overrunning events. These setups can also produce major Ice storms. The 1993-1994 Winter season was a perfect example of Arctic air masses and Overrunning events. I think most here know how that winter turned out.

So what I'm saying is this: as we move into next weekend and early next week, we could have a shot at a storm or Overrunning event. The other thing that concerns me is this. It could also be a Snow to a mix or even rain event. You know the 35 and rain, rinse, wash, repeat, thing that's been occurring, like a broken record for 2 months now. It concerns me in this La Nina like Pattern. Many storms have tracked just to our north and west, just like last year.

My concerns are that any storm developing in the GOM or Deep South could cut just to our west again, and we warm up just enough to have a COLD RAIN. The other concern is that we have too much cold air retreating and too fast.

So to sum it up. I'm not getting too excited about the next 5 days. Nothing worse than wasted cold air, as this has been the case since early December. It's very frustrating and it's painful to see 4 snow events in NYC, all this cold air, and we get SQUAT here!

I'll be updating with more this week, but I really don't see anything exciting to happen until maybe next weekend, or early the following week. Even that is iffy as I've outlined the scenarios !

MY FORECAST FOR THE DELAWARE VALLEY:
Monday through Thursday

Today:
Sunny and Cold with a highs in the mid 30's.

Tonight:
P.Cloudy, and not as cold with lows in the mid to upper 20's.

Tuesday:
M.Cloudy and milder with a rain shower or snow shower possible later in the day. Highs in the Upper 30's to low 40's.

Tuesday Night:
Cloudy with a chance for snow showers mainly during the evening hours. Little or no accumulation expected. Turning breezy and colder with a low's near 20.

Wednesday:
Mostly Sunny skies and much colder, with Highs in the mid to Upper 20's. Clouds will increase later in the day.

Wednesday Night:
Becoming Cloudy with a chance for Light Snow and Snow Showers after midnight. Very Cold with lows in the low to mid teens.

Thursday:
Cloudy and very cold with a chance of some light Snow and Snow Showers. Some light accumulations possible, turning windy with highs in the Upper 20's.
Windy and Bitter Cold with Clearing at night. Lows between 5-10 degrees in the suburbs, to near 10 for PHL. Brrrrrrrr

I'll update more if needed with any possible accumulations for both Tuesday Night and again for Thursday's Clipper events. It appears Later Wednesday Night into Thursday is our best chance for any light snow accumulations.

Take Care,
Ruggie