Monday, March 1, 2010

March Snowstorm !

A HAMMERING OF SNOW COMING TO NORTHERN ALABAMA, GEORGIA AND PARTS OF WESTERN CAROLINAS TUESDAY...



Time is short so I'll cut to the chase. For over a week now we've been watching the models for the setup of a Southeast snowstorm. It's now on the doorstep, and is the longest-tracked snowstorm I've personally ever followed. Kudos to the European Model for latching on to the setup from over a week ago. It however, is a global model and not good for details, which means everything. So, on to the more technical models for subtle things.
None of the models are far enough north with the precip should currently developing and each new run shows the models playing "catch up", a popular theme this year. Which is also why I don't follow models explicitly, as a synoptic forecaster, I have to incorporate what normally happens when upper level features are placed and oriented in certain spots, and I've been hammering this fact for a while...so far it seems the short range models are catching up to my line of thinking.  This upper low is carving its own path and will slowly spin down toward southern Mississippi and then hold in tact while curving northward into central Georgia by Tuesday midday. At the 850 mb level, a 3 contour low will work in tandem with this feature to spread snow across northern Georgia and across northern South Carolina and most of North Carolina. At one point early Tuesday, the 5H trough goes negative tilt on some models, which is very likely considering the physics of how it captures some northern energy, quickly phasing it in, and in response to the Northeast storm leaving a confluent zone behind. This will cause a sudden northward explosion on the northern side of Alabama and Georgia by dawn Tuesday and this moisture will become the deformation axis that spreads a heavy blanket of snow across the western Carolinas and eventually across the tarheel state.

In a nutshell, this storm means business much like last March 1st, where thundersnow and lightning/convection developed in the northwest quadrant and underneath the closed low as it pivoted up Interstate 85. This is a very similar situation, but its going to come down to small scale physics and nuances that decide exactly which zones get hit with thunderstorms and snow simultaneously.  Roughly, Atlanta to Athens to Spartanburg to Charlotte looks likely for this convective snow possibility.  Once again when the coastal low deepens Tuesday evening, a regeneration of uplift on the coastal plain and eventually Outer Banks will be the recipients of heavy wind driven snows, with a powerful, rapidly deepening cyclone.

There will most likely be a sharp cutoff just to the precip, possibly in a line from Asheville to Hickory region, like usually accompanies Upper lows, however this time a strong surface low is also forming in northern Florida, which would counteract this thought, in essence a very tough call to draw the haves and have nots.

The bottom line is a strong Upper low, working in tandem with excellent 500mb features and mid level features , with just barely cold enough air , and dynamic cooling, and some elements of convection, make this potential for an Historic Southeast Snowstorm very real..and its about to begin.

The forecast for Shelby and the highway 74 region between Forest City and Charlotte:

Becoming cloudy tonight with light snow or rain developing after midnight. Lows near freezing.
Tuesday...Snow developing around daybreak. Heavy snow and thunderstorms possibly during the afternoon. Becoming windy with temperatures holding around 32.
Tuesday night..snow ending. Lows mid 20's.
Snow accumulations across the region will vary tremendously, with some areas getting only 1" and others closer to 85 getting over 6".

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