Saturday, March 3, 2012
Late Season Snowfall North of I-40 Sunday Night
Good Afternoon...After a rough night of severe thunderstorms old man winter could pay one last visit before taking a vacation. A late season clipper system will race into the region sunday and bring clouds and limited moisture. However enough moisture apprears likely for light snow accumulations on the plateau.. the mountains and areas in the valley north of I-40 up into the Tri Cities. Since this snow looks to fall of the night wet accumulations appear likely. Temps sunday night will drop below freezing so hazardous driving conditions will also be possible.
Thursday, March 1, 2012
Significant Tornado Outbreak Possible Tomorrow
A vigorous low pressure system will traverse the western midsouth into the great lakes region. This low will probably be very well organized and will likely go sub 990 milibars as the LPS matures. As it starts to move northeastward an associated warm front will move through the area overnight and there could be a few severe storms that fire along this warm front tonight into the early a.m.
IMO this warm front will be the most important equation that will ultimately decide how significant tomorrows threat will be. If the warm front moves through rather quickly then look out... its gonna get nasty. The slower the warm front retreats northward the less significant this threat will be. With a slower moving warm front you will have junk convection trying to stabilize the atmosphere ahead of a very powerful cold front.
There's gonna be severe weather either way but if that warm front and its associated convection moves through the area rather quickly the surface layer airmass will establish a very favorable thermodynamic enviroment where the sun will begin to break through the clouds warming surface temps...then the atmosphere will become VERY unstable due to the high cape/high shear.
If that happens discrete rotating supercells will likely invade middle and east Tennessee transforming into line segments as the cold front nears the spine of the Appalachians. There could also be embedded supercells in these line segments. If things do go downhill tomorrow it looks like the western plateau area would be right in the bullseye and folks in east TN will have to endure a nocturnal Tornado threat which is a whole other creature itself.
There's alot of if's involved in this setup and this event could wind up being either a standard severe weather outbreak or an extreme one... so I would just stay tuned to my local NWS office and its radar.
IMO this warm front will be the most important equation that will ultimately decide how significant tomorrows threat will be. If the warm front moves through rather quickly then look out... its gonna get nasty. The slower the warm front retreats northward the less significant this threat will be. With a slower moving warm front you will have junk convection trying to stabilize the atmosphere ahead of a very powerful cold front.
There's gonna be severe weather either way but if that warm front and its associated convection moves through the area rather quickly the surface layer airmass will establish a very favorable thermodynamic enviroment where the sun will begin to break through the clouds warming surface temps...then the atmosphere will become VERY unstable due to the high cape/high shear.
If that happens discrete rotating supercells will likely invade middle and east Tennessee transforming into line segments as the cold front nears the spine of the Appalachians. There could also be embedded supercells in these line segments. If things do go downhill tomorrow it looks like the western plateau area would be right in the bullseye and folks in east TN will have to endure a nocturnal Tornado threat which is a whole other creature itself.
There's alot of if's involved in this setup and this event could wind up being either a standard severe weather outbreak or an extreme one... so I would just stay tuned to my local NWS office and its radar.
~ Toot
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