Severe threat Limited, Mainly North, Cooler Not Frigid Weekend

Since we are in the warm air sector and a cold front is approaching, we will continue to have a threat for some strong T-Storms overnight into Tomorrow.  The upper energy is near Amarillo, and it quickly races to the NE by late Saturday.  Since this system appears to be progressive and not a slow mover, I don't expect any widespread flooding.  SPC has not increased the severe threat, keeping us in a level 2 (slight) risk through Saturday.

Radar currently has most of the rain/storms well to the north & west of NOLA.  Those of you on the North Shore need to pay attention, as the severe threat/danger is greatest north of Lake P.  The upper low is still well to our west over the Texas Panhandle.

Since models quickly move it to the northeast on Saturday, WPC has lowered their total rainfall amounts, with the South Shore lucky to get an inch.

We will be noticeably cooler for this weekend, but this is not an Arctic Outbreak as the upper flow doesn't deepen until next week.  We begin with today's upper flow, followed by Sunday.

You can see on the bottom graphic (Sunday) that the base of the trough doesn't dig down to the Gulf Coast.  Compare that to the GFS forecast for the following Sunday (1-18).  The trough is deeper and farther to the west.  You snow geeks should get excited, as this hints at a southern snowstorm.  But that is way out and likely to change.

Today was another 80-degree day, but model guidance indicates it might be the last for this month as the second half of January will be much colder.

 If you're north of Lake Pontchartrain, pay attention to the radar & your FOX 8 Weather App tonight & early on Saturday.  The severe risk is far less to the south.  Finally, I will post my next podcast on Monday, talking about the Polar Vortex and why we haven't stayed cold this winter. Sign up to subscribe at bobbreck.com.  Enjoy your weekend and stay tuned!

Southern Severe Threat Increases, Greatest Danger Staying to Our North

It's a little early for our spring severe weather season to begin, but we are in the warm air sector with low-level Gulf moisture increasing and a cold front approaching. Watching the local noon weathercasts was very frustrating, as no one really explained why the severe threat danger for us has increased, except to show us the SPC map.  The top graphic is YESTERDAY'S SPC's outlook. Note, we were in the level 2 risk.

The next two are from today.  Ignore the number one over Terrebonne. The yellow (Level 2) now covers all of SE LA/MS.  So what has changed?

The first upper low is already in Iowa, taking its energy far to our north.  It's the second upper low over the 4 corners that is taking a track at a lower latitude.  That will bring its energy closer to us, increasing the severe threat farther to the south.  The WPC's rainfall map has also shifted the heavier rains to the south.

The orange/reds indicate 3-5"+ rainfall over the next 3 days.

The FOX 8 model clearly keeps the heaviest rains well to our north, with totals south of Lake P. less than one inch.  What we need to watch for late Friday into Saturday is where does the upper-level jet stream split (diverge) over the South?  That's where the heaviest storms will develop.  SPC will likely issue several Tornado Watches, so we'll need to pay attention.  Here's the latest rainfall forecast Nicondra showed at 4 PM.

It has shifted some heavier amounts (2-4") over the North Shore, but it keeps the South Shore around one inch.  Not sure why NWS has included parts of the South shore in a Flood Watch for late Friday into Saturday, except as to be cautious.

OK, so the first upper low takes any severe threat far to our north and weakens it for tonight and early Friday.  It's the second upper low that will bring a severe threat late Friday into Saturday.

As you can see, we are in the warm air sector with dew points (bottom graphic) rising well into the 60s.  All that is needed now is the lift provided by that 2nd upper low and the surface cold front.  But all the local weathercasters show you are models and not what they think.

 

To me, it appears a line of heavy storms approaches overnight on Friday, but weakens.  Several lines try to form on Saturday, but none look too impressive.  Let's just pay attention late Friday into Saturday in case something changes, and storms start to fire off.

There definitely is a cool down coming that will bring back the heavy weather gear for next week.  Another stronger shot of cold air arrives later next week.  After a warm beginning, January appears to be headed towards a cold (normal) next 2 weeks.  I am working on a Polar Vortex podcast, and we will have another with Zack Fradella coming up behind that.  Sign up at bobbreck.com.  Stay tuned!