Severe Threat–Saturday 3/23/13

Here is the current surface setup this morning.  We currently have a weak area of low pressure centered over Central Texas around the Dallas metro area with a warm front extending across the northern Gulf Coastal plain and Black Belt areas.  The movement of this warm front will be vital in just how unstable portions of the deep south get on this afternoon and Saturday when it comes to the potential for severe weather.  A rather deep upper trough to the east will keep cool advection coming in pretty strong to the north of the warm front, but a deepening wave to the west should turn winds more southerly and at least get the surface features moving northward somewhat in response.  These are all questions that will become resolved in the next 24 hours.

The day 2 convective outlook from the SPC highlights a good chunk of Alabama in a SLGT risk (standard risk) of severe storms for Saturday afternoon and into the overnight. 

A 30% risk area has been defined from areas encircled from a Monroe, LA – Dothan, AL – Tuscaloosa, AL  – Jackson, MS region.  This area is expected to see the most unstable air mass during this period and will likely be in the uncontaminated warm sector for a decent period of time.  Thus, diabatic heating could allow temperatures to soar into the mid 70’s to lower 80’s.  This will need to be monitored for a possible upgrade to moderate risk if these factors do indeed come together. 

At this time, we look for scattered cellular development to take place across Mississippi and Alabama tomorrow afternoon with the threat of hail, high winds, and a tornado or two.  The hail threat could be rather significant.  Then, the instability axis is forecast to spread northward toward the Tennessee Valley ahead of the cold front and allow for a strengthening line of severe storms to push through much of Central Alabama.  We will continue to keep you alert of changes with the situation through early tomorrow.  Stay tuned as we will likely have teams in the field for this potential high impact weather event.

#More Heavy Rain & #Severe Storms This Week

February is turning out to be quite the weather month thus far with it just barely halfway gone! We have been faced with a number of setups this winter which haven’t quite materialized as all the needed ingredients haven’t come together. Unfortunately all those ingredients did come together on Sunday February 10th as MS saw numerous Tornadoes, Hail, Damaging Winds, and Torrential Rain! Of course the now infamous tornado that struck Hattiesburg, MS was part of that outbreak. The official storm survey, radar documentation, and analysis is in and that is the first link in this post. Please take a minute if you haven’t to read about how the Live Storms Network played a life saving critical role in the tracking of the dangerous weather that afternoon. NWS WFO Jackson, MS is a newly dual-pol upgraded site and one thing unique to this outbreak is that the new dual-pol equipment played a vital and key role in detecting the situation as to what was really going on: coupled with ground truth live streaming feed from Live Storms Network and Law Enforcement. Take a minute to find out how all this came together and not a single life was lost. Hattiesburg, MS Tornado Survey/Dual-Pol/Analysis (Click Here)

February over the next 7-10 days appears to be a very active period with snow, flooding rains, and severe weather. Right now a large and potent storm system is off in the Pacific Ocean which will dive south towards the Rockies before ejecting Northeast. It will be bringing with it a major winter storm including multiple inches of snow, sleet, and freezing rain. Right now with the storm system sitting so far off the coast it isn’t full in our observation network for our models to pinpoint the specifics—how much, when, and where. The one thing that is for certain is that it is coming! That is just the first part of the weather story to the week…

Above The Graphical Images: 1.) GFS 30 Hour Precip/MSLP; Below: 2.) GFS Snow Depth; 3.) NWS WFO Kansas City/Pleasant Hill

Now To Part Two of the system (heavy rain and potential severe weather). After the above mentioned system ejects to the Northeast a secondary frontal wave will develop and move through the Texas to Lower MS Valley. This is where a window of opportunity will exist for boundary layer destabilization and vertical shear to support several modes of severe weather. This area is expected to be overspread by difluent upper flow, just north of the subtropical jet axis. This will allow a window of opportunity for a squall line to develop and possible supercellular development in nature as well. The one thing that must be overcome and achieved to materialize a severe weather event including tornadoes (a strong one or two at that) is the degree of moisture return in time. Right now models indicate an influx of rapid moisture Wednesday bringing PW values to 1.5 inches and mid 60′s dewpoints. Marginal instability looks to be present on Thursday/Thursday night (400-600 j/kg 850MB, 300-500 ML Most Unstable). However shear values are expected to be INTENSE in association with the 50-60 KT 850 MB jet that is forecast to develop. 0-3KM Helicity values in EXCESS of 700 (!!!!) and 0-6KM Shear in excess of 60-70 Kts indicate VERY stout shear profiles will be in place for Thursday/Thursday Night. With 0-1KM Shear forecast to be in excess of 40 kts coupled with other intense shear dynamics sets the potential for tornadoes (possibly a strong one). Flooding rains will continue to be an extreme concern as we will be seeing healthy amounts of rain starting today (Monday) and going through the week. Models diverge on how far south the front will get which dictates anywhere from 1-2 inches on the conservative end to 4-6 inches advertised by the Euro through Sunday. Temps run somewhat seasonal heading through the week with the daily high’s and nightly low’s till Thursday comes and moisture transport warms things up a bit more.

Graphical Forecast Product From WFO JAN…

The Storm Prediction Center has elected to include our region in a slight risk for the past days and it currently is in its’ Day 4 Status Day 4-8 Textual Discussion Regarding Severe Weather Thursday (Click To Read)

As ONE more parting thought via SPC after the Thursday event: it appears another vigorous impulse may progress through the upper trough and contribute to strong surface cyclogenesis east of the central and southern rockies late next weekend into early next week. At this time the model spreads are too large but will be monitored for any consistency to introduce a regional severe weather event!

Looks like a VERY active next 7-10 days and you can count on the Live Storms Network and Live Storms Media Team To Keep you Updated with the latest forecast, analysis, and of course LIVE FIELD ACTION BRINGING THE STORM TO YOU!! –Forecaster Jason Brand

Severe Wx and Chaser Update

Our chasers are getting into position for severe storms including the potential formation of supercells.  I know that John and Brantley are headed toward the general area of McComb, MS along I-55.  Nick is further north and just ahead of a severe line of storms that is impacting the Yazoo City area.  Some rotation has been noted in those cells.  We will keep you up to date on what is happening, but you can watch each of them LIVE by clicking their tabs at the top of the page! 

Severe Threat Increasing.. #MSWX

The threat looks to be increasing across portions of the MS Delta region this morning as continued return flow has become established across much of Mississippi ahead of the cold frontal boundary and associated upper air trough.  The Storm Prediction Center has highlighted parts of the region for potentially significant tornado development from late morning through the evening hours.  Brantley French and Jason Brand will be in the field streaming video here on LiveStormsNOW.com during the event.  Click his name above or within this post to watch the live feed.  More soon…