Saturday, November 3, 2012

East Coast Snowstorm? yes. VA snowstorm? not so fast

I've seen talk and have been asked questions about the potential for a significant east coast storm this upcoming Tuesday-Thursday (11/6-11/8).  There's been talk of heavy I81 snows, significant impacts to areas impacted by Sandy, etc.  I do believe that there will be problems along the Jersey coast.  Nor'Easters generally generate a decent 2-4ft+ storm surge.  With tons of beach erosion from Hurricane Sandy, many of these areas will have problems with this..not to mention all those still without power dealing with cold, heavy rains..possibly changing to snow on the back edge of the storm.  So what's the deal with Virginia?  Well the last few runs of the Euro have been showing heavy rainfall east of I95, with enough precipitation being kicked back into the cold air west of I81 to cause heavy snow fall accumulations for these areas..especially across the northern Shenandoah Valley/eastern WV/western Maryland.  Here's what the 12z Euro looked like from today:

This is the Euro.  This is the king of all operational models showing 6-12" from the central valley on north.....but..  I'm still not excited about the threat yet.  Remember when the Euro was showing a Delmarva landfall with Sandy, while many of the other global models took her too far north and east, either out to sea or landfall into New England?  Yes, the Euro was right with the more southern landfall...but it still ended up being farther north than what it showed...into southern Jersey.  Sure, that may only be 50-75 miles..but look what happens to the precipitation shield if the Euro is off again this run by 50-75 miles.  There won't be any precipitation thrown far enough west to even meet the cold air coming into western Virginia.  With Sandy, a key that kept my Atlantic City landfall consistent the whole storm (even while the Euro operational was showing farther south into the Delmarva or the Eastern Shore) was that the Euro ensemble runs consistently stayed farther north into Jersey/NYC area.  That was a red flag to me, showing that the Euro may be a bit extreme in how far south and west Sandy made landfall.  So what do the Euro ensemble images look like with this upcoming storm? is the 00z operational run of Sandy with a coastal storm not too far off the shore...close enough to spread snow into western VA/eastern WV.

Now here is the 00z Euro ensemble mean...notice how much farther east the coastal storm is...not close enough to have a precipitation shield stretching much farther west than I95.

The 12z euro ensemble runs that came out this afternoon are looking very much the same as shown above. This is almost dejavu in terms of model disagreement with Sandy.  You have the GFS that takes landfall way into New England, the Euro that is the most south/west solution, and the Euro ensembles, which are somewhere in the middle.  I expect the Euro operational to end up being the outlier again with this system...with a gradual trend east with the track over the next 24-36 hours. So..yes...I think there will be a significant coastal storm for the northeast.  I think areas of eastern Virginia will see some heavy rains, gusty winds with this...nothing too significant...or anywhere close to what they saw with Sandy.  Some areas of the Northeast will get good snows, mainly higher elevations west of I95 in central PA/NY especially.  I'm not completely ruling out some snow showers for northern VA...but right now...I'm not biting on the significant heavy snows that some are jumping on.

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