Severe Threat Later Today, Much Colder Monday & Tuesday

The SPC (Storm Prediction Center)has not backed off on the severe potential tonight and tomorrow for a large area of the eastern United States. The reason is that a vigorous upper-level dip in the jet stream is diving down the central Plains and will be over the Northeast by late Monday.  It is pulling up warm air from the Gulf, colliding with Arctic air diving out of Canada.

SPC has expanded their level 3 severe risk for tonight into Monday (middle graphic), increasing it to a level 4 for Monday along the eastern states. It should be mainly a wind damage event for South LA/MS, with the Tornado threat staying farther to our north.  However, damage is damage whether it's from straight-line winds (very likely) or small tornadoes (very unlikely).  There are Tornado Watches out for many states, but this system is just getting started.

Severe storms are developing in the warm air sector, while blizzard conditions are north and west of the surface low.

 

The only limiting factor right now is the low-level moisture (dew points 60+) is confined to the Gulf Coast.  That will change overnight as the upper energy rounds the base of the trough in Texas.  

Visibilities are near zero because of the dust.  That energy will help ignite T-Storms along the southern end of the front.  It should reach us between 10 PM -2 AM, long after most of us are asleep.  Make sure you have your phone by your bed and have your FOX 8 Weather App ready to go in case warnings are issued.  Check on FOX 8's late weather programs tonight before you go to bed.

This will be a short 2-day cool-down and you'll need to protect your tender plants, especially on the North Shore.   I suspect the main wind damage will stay well to our north with the greatest upper energy, but we need to pay attention just in case the southern end of the squall line turns severe.  Heavy coats and sweaters are needed Monday & Tuesday.  Stay tuned!

Strong Sunday Night Front, Another Severe Threat, Heavy Coats Required Monday

 It's hard to believe that we'll have to go back to Sweaters & heavy coats again after being in the 70s & 80s.  However, previous posts have mentioned we are not done with Winter and will see many more cold fronts well into April.  This next front will be a slap in da face on Monday morning as strong north winds will have windchills here down into the 30s.  Why will that happen?  Let's begin with the current picture.

Sunday will be warm here as the cold air is far to our north.  However, look at how the upper pattern flips from now until Monday.

We basically have a west to east flow across the lower 48 as an disturbance deepens over Idaho.  Look at how the upper trough reforms over the eastern states.  On top is the current followed by late Sunday PM.

The bottom is for Monday morning with a full blown upper East coast trough.  That will bring down the super cold (20-30+) below zero air out of Canada.

With such strong upper energy/dynamics clashing with a huge temperature contrast and rich low level moisture, strong to severe storms are almost guaranteed to develop.  SPC has issued a level three severe risk for Sunday to our north including a level 2 risk here.

 

That risk quickly shifts to the East coast on Monday.  This event for us should be mainly a straight line wind damage event coming well after dark on Sunday ending before daybreak on Monday.

The coldest mornings will be Tuesday & Wednesday with a light freeze possible on the North Shore and some frost away from Lake P. south.  You should consider protecting your tropical plants and tender vegetation before we warm right back up later next week.  Before then, we need to pay attention to the possible severe threat for after dark on Sunday night.  Make sure you have your phone nearby your bed so you can receive any warnings though your FOX 8 Weather App.  Many will be focused on the parades this weekend which should have no weather problems.  St. Patrick's Day will be sunny but cold, a beautiful day IF you're dressed for it. Stay tuned!