Friday, January 18, 2013

January 29-31 Potential Winter Storm


Images courtesy of TropicalTidbits
The models are hinting at the evolution of a potentially major storm system that would affect much of the central and eastern US.

Above are two forecast images from TropicalTidbits, showing the forecasted sea level pressure and precipitation in mm/hour. The top image is valid on the morning hours of January 30th, with the bottom image valid the evening of January 30th. The synopsis involves a storm system cutting along the the Midwest from the Plains and into the Ohio Valley and eventually the Northeast. Throughout this process, strengthening appears to be the key word of this system, as it eventually drops to 982 millibars off the coast of New England. If you look really closely, you can make out a blue dashed line with the number '540' on the line. This is the rain snow line; any precipitation north of the line is snow, and any precipitation south is rain. Using that as our guide, the GFS calls for possibly upwards of 1 foot of snow in parts of the Midwest, with possibly amounts nearing 10 inches in portions of the Northeast. If only this were a trustful forecast. Alas, beyond 5 days out the GFS model is biased towards making storms too strong and temperatures too cold, giving many the long range forecast of over a foot of snow, only to find rain and warmer temperatures when the forecast verifies- and that's even if the storm happens!

Either way, I will provide updates on this storm as the date draws closer, but for now, don't get too hung up on the forecast.

Andrew

3 comments:

Scott Schneider said...

Keep us posted Andrew!! Hopefully the wise-guys out in internet-land won't keep holding to this "exact" forecast nearly weeks out. . .:)

Jeremy S. said...

That rain/snow line is ridiculous. It leaves, basically all of the Mid-Atlantic, New York City, and even Boston above freezing. C'mon!! Something seriously has to give!

Ray T. said...

Looking good, though latest models have trended a bit further north. I know you have not had a chance to update just yet, but just a heads up! Keep up the good work buddy!