Friday, January 9, 2009

My Call: Accumulating Snow and Mixed Precip On The Way For The Delaware Valley. Further North and NE, Moderate Snow Accumulations Can Be Expected !

My Call: For Saturday/Saturday Night Snow Event.
Issued: Friday 1/09/09
For: The Delaware/Lehigh Valley's & The NYC Metro Areas.

Well Guys here we go again with another tricky call ! A very critical storm track, and some players on the field for Saturday into Sunday AM, will make this a call tough, but I'll give it my best shot !

The Storm Track:
A Low pressure system now over the Southern Plains, will move east to the Tennessee and Lower Ohio Valley region later tonight. This low will be near Kentucky/WV, Saturday AM. Snow will spread eastward from The Ohio Valley and into our western area's during Saturday morning.

During Saturday afternoon and evening, the storm tracks across Northern VA and into Northern MD. This will allow some snow to move into the NYC Metro area by early afternoon. As the storm tracks east, and closer to the Delaware Valley, some milder air aloft will likely cause the snow to mix with and possibly change to sleet and rain, for later in the day and into the evening hours. Areas North of PHL should remain mostly snow, but some sleet will mix in over SE PA and into Central NJ.

Later Saturday Night this storm could intensify some, as it moves just off the NJ coast and then continues ENE and offshore during Sunday AM. With this track, any mixed precip would change back to some snow for areas South and East of PHL. Snow and Sleet will continue moderate at times during Saturday Night and into Early Sunday AM, for areas North and East of PHL, and into the NYC Metro area.

Other Key Players:
A couple of key players will be important with this system. First the track and strength of the H85 low will be critical for the precip types, in our transitional regions near the PHL area. The second player will be High Pressure over New England. The strength and positioning of this High Pressure system, could allow for a weak CAD signature, and help hold off any milder air aloft from working in. A 1020 Mb High is not really strong, but isn't that weak either. A slightly stronger High, and it's positioning being further south, could be a factor, so these key players are something to watch for, as we head into Saturday.

General Snowfall Amounts:
The areas which are most likely to see mainly snow, and Moderate Accumulations will be North of PHL. Areas from just North of PHL into Central NJ, and The NYC Metro areas will have sleet mixed in later Saturday Afternoon and Evening.

For The Lehigh Valley, The Poconos, and much of Northern NJ:
Most of these areas will see 4" to 8" amounts, with the higher elevations, from the Poconos into NW NJ, seeing some isolated amounts of near 10". So overall a good hit can be expected. Our friends up north are "The Lucky Dogs" once again ! Ha

For The Far Northern & Western Suburbs of PHL, Central NJ, NE NJ, and into NYC & Long Island:
A general 3" to 6" of snow and sleet can be expected. Isolated Higher amounts are possible over Northeast NJ, and The NYC area.

For PHL, Interior Southern NJ, and Northern DE:
This is where things get very tricky in forecasting snow amounts. This region is likely to start and end as some snow/Sleet, but will have mixing/Changeover issues that will hold down accumulations to a general 1 to 3". A prolonged period of sleet, and rain mixed with some snow, will occur from Saturday afternoon and into the evening hours. Some freezing rain is also possible Saturday Night. Ouch again ! Man that hurts.

The bottom line is the closer you live to PHL, the better chance for 1" or 2". The further south & east of PHL, into Northern DE and Interior Southern NJ, well the lesser amounts of a 1" are more likely.

The Key Player If's I talked about earlier: The storm's exact track and the amount of milder air working in aloft, will leave this area in a transition zone, that could allow for more snow or even less. My general thinking is for a 1" to 3" but if the storm should take a track 50 to 75 miles further south, these amounts could increase to say 2" to 4". But a shift further north with the storm track, then amounts could be closer to 1". You get the picture Right !

For Extreme and Coastal Southern NJ, and into Central DE:
A Coating in spots can be expected, as a mix of Snow,Sleet, Rain quickly changes over to rain and sleet during Saturday afternoon and Saturday evening. This precip. could change back to a brief period of snow and sleet, before ending later Saturday night.

SNOWFALL MAP: Click map to enlarge

Good Luck and Enjoy !


tom said...

i would love to see 1-3 in philly but as of right now i would think ice is the prodominate thing then over to rain. I think next week is are time. This storm never was suppose to be something big for philly.


Hey Tom,
Yes some zr is quite possible near PHL and Interior SJ/Northern DE for tomorrow evening. Some snow and IP at the beginning and end of the storm with 1" to 3" possible.

Next system on Tuesday looks like a light accumulation, but Wendesday Night into Thursday could be a good hit for us. I'll keep and eye on that one. This is the storm I mentioned a few post back for later next week.

Take Care