Saturday, January 5, 2013

Update on Heavy Rain / Severe Weather Event for Texas and the Lower MS Valley...

I wanted to give a quick update on the storm system that I detailed in a post yesterday, and its potential impact on Texas and at least the lower Mississippi Valley region for the early to middle of next week...

First things first, a significant (and much needed) rain event will take place across the central and eastern two thirds of Texas, southeastern Oklahoma and much of Louisiana and Arkansas.  Most of this rain will fall during the period Tuesday through Wednesday:



As you can see on the cumulative rainfall forecast image above, widespread rainfall amounts of 2-4 inches are expected, with localized amounts of 4-6 inches possible across much of the region.  This rain will be very welcome indeed, as the vast majority of this region continues with a severe to extreme drought situation:



As I mentioned in a post yesterday, the European computer forecast model has been the most consistent thus far in forecasting this storm system, and I believe that it continues to be the most reliable with its depictions through today.  The latest run of that particular model is forecasting 4 inches of rain to fall in Austin, mainly from 12 Noon Tuesday through 12 Noon Wednesday, as shown on the graph below:


While the rain will certainly be welcome across the region, on the negative side of the coin, a threat of severe weather will come along with it as well.

While some of the severe weather details still need to be worked out (mainly with respect to timing), the area shown in red on the image below is likely to have the highest threat of severe weather on Tuesday, which includes the Austin-San Antonio corridor along I-35, "The Valley" in Deep South Texas, the Texas Coastal Bend and the Houston metropolitan area:


I still believe that the situation for Tuesday looks very similar to that of the heavy rainfall and severe weather event that took place across the Austin-San Antonio corridor area during the early morning hours of January 25, 2012.  That particular event produced widespread heavy rainfall (in excess of 6 inches in some locations), damaging wind gusts and at least 1 tornado.

While it is still too early to pinpoint some of the details as to the severe weather threat, if you live across the region shown in red on the map above, please pay attention to the weather on Tuesday and Tuesday night.  Make sure that you a have a way to receive severe weather warnings and identify your best sheltering option in case threatening weather approaches your area.

The threat of severe weather will shift East/Northeast into Louisiana, southern Arkansas and still the Northeast part of the Texas coast (including Houston) as well as east-central Texas for Wednesday.  More details on the Wednesday severe weather threat will be available tomorrow as the situation becomes more clear.

For more information from 'The Original Weather Blog', including shorter, more frequent posts during rapidly changing weather events, please be sure to follow me on facebook and twitter:
 
If you are in need of highly customized, site specific weather forecasts and/or storm warnings for your business, school or event, be sure visit my professional webpage at WeatherGuidance.com.

8 comments:

ryan hearne said...

I live in dripping springs,tx and i remember december 25,th 2012, that was a big storm, but would there be a severe threat at all considering the spc forecast forecasts no severe weather?

Rob White said...

Ryan, thanks for the comment/question.

Do you mean January 25? That's the event that I was referring to...

As far as the SPC is concerned, I have pretty consistently found that a forecast event almost has to qualify as a "moderate" or "high" risk situation (as per their criteria) before they insert an outlook into the Day 4-8 period.

If you read the Day 4-8 discussions for the past 2-3 days, they are suggesting that some severe threat appears likely, but they typically cite model inconsistency in refraining from an outlook. The European model has been extremely consistent with this system, so I can only assume that they're referring to the GFS which has been inconsistent, but recently trending toward the European solutions.

Here in the private sector, we've been advising our clients of the heavy rain and severe weather threat for more than a week now...

In my opinion the main considerations for severe weather right now come down to timing and the amount of airmass stabilization from potentially widespread heavy rainfall. As we saw on 1-25-12, the widespread precipitation was not a limiting factor, so it will be interesting to see what happens this time around.

ryan hearne said...

hey thanks for the info i use your site all the time for severe weather.
i meant january:)

Rob White said...

Ryan, thanks, no problem. Several upgrades/changes coming to the blog site this spring for severe weather season, so stay tuned!

Also, note the SPC finally introduced a risk area on the Day 3 Outlook. Should see them get more "excited" today and tomorrow I think...

ryan hearne said...

It seems as though the main severe threat (being damaging winds and flooding) is most likely to occur around the coastal tx. areas including corpus christi tx., to houston,tx. in my opinion this will be lesser of a severe threat event for central tx, including austin,tyler,and san antonio,tx, than the event that happened on january 25,2012. i believe it will mainly be a rain event. i do believe you should add the threat of hail potential. This is my thought, severe weather will be mostly isolated supercells, if any.
They will be located around the coastal areas of texas...I do have a thought that maybe spc forecast could include the extreme south central tx counties, as i believe there is potential in that area for some isolated severe weather. Whats your thought?

Rob White said...

Ryan, thanks for the comment. I apologize for the delayed response, I've been swamped the last 24 hours.

Please see my recent post for the latest trends/thoughts...

Austin-San Antonio corridor will receive at least 2-4 inches of rain, with 6 inches certainly not out of the question, especially if recent high resolution model trends of "training" thunderstorm activity Midnight to Noon Wednesday verify.

On the severe weather side of the coin, it looks to me like there'll be more shear than buoyancy, which would be a wind damage/tornado threat more than large hail. I wouldn't expect any hail to average more than 1 inch diameter based on the expected vertical thermal profiles.

Very strong likelihood of rotating storms both along and South of the warm front, which will be Deep South TX tomorrow afternoon/evening, spreading N into the AUS-SAT areas tomorrow night, then shifting into SE TX for Wednesday.

We certainly need the rain, hopefully we can keep flooding/severe to a minimum along with it...but we obviously have to take what we can get!

boston corporate event venue said...

Every experienced event planner will tell you that there should arise a few problems along the way. Event planning includes time and efforts for a successful event.

Alexandra Kate said...

I was about to say something on this topic. But now i can see that everything on this topic is very amazing and mind blowing, so i have nothing to say here. I am just going through all the topics and being appreciated. Thanks for sharing..........................