Tuesday, January 29, 2013

Temperatures to Rise Above 32 Today!

For the first time since the afternoon on January 20th temperatures will rise above freezing (albeit barely).  A very strong cold front is developing in the Midwest/Great Plains and pushing warmth into Southern New England.  A severe weather outbreak is expected today in these regions here

SPC Tuesday Thunderstorm Outlook
Temperatures today will be in the low 30's.  The coldest spots in the region may not break 32 but I am expecting a high of 37 for Boston, 34 for Worcester, 36 for Providence, and 36 for Hartford.  Winds will begin to increase overnight.  As I wrote yesterday I expect some rain tomorrow.  This is an interesting set up and it wouldn't surprise me to see Wind Advisories or High Wind Watches posted today.  

00z GFS 900 hpa Winds mslp (image wxbell)
This is valid 7 PM EST tonight. I've circled the subtropical Atlantic High pressure and a wave low pressure that will form and deepen along the baroclinic (thermal, or temperature gradient) zone.  Here is the forecast surface temperatures at the same time
00z GFS 2 m Temps (image wxbell)
You can see the contrast between warm and cold.  So the pressure gradient force and the baroclinicity are favorable for a strong storm.  That warmth will be pushed into New England via a 500 mb ridge

00z NAM 500 mb vort valid 7 am Tues
The big dip in the west is pushing east.  There are ridges on both the east and west coast.  Temperatures tomorrow will soar into the 50's.  Some light wintry precip will fall in the higher elevations tomorrow morning;  the warmth is moving in aloft but the cold will hold on strong at the surface.  Eventually the cold front will have to push through overnight Wednesday with 1-2 inches of rain and strong winds.  

I'm not sure how much of this will mix to the surface.  It depends on whether or not there is convection.  The cold air can inhibit mixing as well so we will also have to watch temperature trends.  
00z Hires NAM 900 mb windsm mslp 10 PM Wednesday
Here are the 3 day rainfall totals
HPC 1-3 day precip totals
That's all for now, have a good day!







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