Strong storms are possible this evening prior to a cooler and quieter second half of the week.

THE FORECAST:

Today and Tonight: After a dry beginning, clouds are expected to increase through Valentine’s Day and showers and thunderstorms may disrupt some plans later. As of now, timing brings action into the area close to the afternoon commute which could mean a dicey drive. Additionally, a few storms could be severe. Stay in touch with the forecast for updates and any alerts. Highs will make it into the upper 70s. Overnight, thunderstorms will end from west to east with just a few lingering showers possible into the morning. Lows will drop into the low 50s as winds shift to the northwest. 

The National Weather Service Storm Prediction Center (SPC) has issued a “slight risk” for severe weather this evening. This means an isolated severe storm is possible within the forecast area. On a scale of 1 (lowest) to 5 (highest) severe weather threat, this event is a 1. Another way of describing the threat is that there is a 5 percent chance of experiencing severe weather within 25 miles of a given point in the risk area. This storm system will not bring widespread, intense severe storms like last Tuesday. Still, we must give respect to the threat as one or two spots in the 13 Parish, 3 County forecast area could see a nasty storm.

Possible Threats:

1) Gusty Wind – in storms that turn severe, wind gusts could exceed 58mph.

2) Tornadoes – plenty of low level wind shear will give storms that do develop the ability to rotate.

3) Hail—in the most intense storms, some marginally severe hail (1” in diameter) could make it to the ground.

Precipitation: Generally, less than a half inch of rain is expected, though a locally higher amount could occur within the 13 Parish, 3 County Forecast Area—especially where the heaviest storms occur.

Estimated Timeline: The timing of this system is pretty straightforward. Showers and thunderstorms are expected to arrive in a cluster or line during the afternoon hours. At this time, areas west of the Mississippi River should see the onset of rain and storms by 5pm with action making it to Baton Rouge by 7pm and I-55 by 9pm. The main issue with timing is arrival. Should the system speed up and move in just an hour or two earlier, the late commute could be significantly affected, so keep in touch for forecast updates. The severe weather threat will be relatively short in span, with the greatest likelihood for strong storms at the leading edge of precipitation. While some showers may linger overnight, impact weather will conclude by midnight.

Impacts: Have a Valentine’s Day dinner date? Carry on… just be sure you have access to alerts while out and about. Know that travel could be difficult in a brief downpour or in the event of severe thunderstorms. For the most part, indoor restaurants and movie theatres are safe places in severe storms. Just remember in the event a tornado or severe thunderstorm warning, move away from windows. And to repeat, if the storms arrive just a tad earlier than current expectations, the late commute could prove difficult. Monitor the forecast and be prepared for delays if storms arrive sooner.

Actions: Have access to watches and warnings such as with a NOAA Weather Radio or from the WBRZ Weather Team on Facebook and Twitter. Additionally, the *free* WBRZ WX App. sends push notifications to mobile devices if a watch or warning is issued for your location. Remember, a watch means “conditions are favorable, and a particular threat could develop” and a warning means that “threat is happening and you should take action immediately.” In a tornado warning, seek shelter in a low-level interior room and avoid mobile homes is possible. In a severe thunderstorm warning, get inside of any sturdy structure.

Up Next: Clouds will break from west to east through Wednesday. Some sunshine is possible by afternoon. With winds turned around to the north, highs will stop in the low 60s. A seasonably cool start is anticipated on Thursday with highs back into the low 60s beneath ample afternoon sun. Clouds and mild air will return quickly on Friday Afternoon. There will be just a slim chance of a passing shower overnight into Saturday followed by a warm weekend with partly to mostly cloudy skies.

THE SCIENCE: A negatively titled shortwave trough moving into our region will merge with a longwave moving out of the Great Lakes Region this evening. As it does so, the trough will become more neutral. An associated surface low and cold front will move across the Central Gulf Coast in response to this phasing. Instability is expected to be limited while helicity will be high. This all sets up the typical conditional Central Gulf Coast winter time severe weather threat.  A cluster of showers and thunderstorms, perhaps congealing into a line, will move into the area during the evening hours. Given the front forcing, a few updrafts may become strong enough upon breaking through a stable surface layer. Wind fields will be strong enough that gusty winds could mix down or a tornado could spin up along the leading storms. As far as duration goes, the severe weather threat should be generally limited to the onset of storms. The SPC continues to carry a “marginal risk” of severe storms with gusty wind, isolated tornadoes and hail the top three threats. By midnight, most of the action will be wrapping up with just lingering showers into Wednesday Morning as the cold front sweeps east. A surface high pressure system in the Mountain West will allow northerly winds to push cooler temperatures into the area for Wednesday and Thursday. Highs will be closer to normal until Friday when the high shifts off of the East Coast and return flow kicks back into gear. A fairly sharp shortwave trough will kick through Friday into Saturday. Right now, the moisture fields look limited meaning passing clouds are the most likely scenario but this will need to be watched for a few showers if the lower levels can saturate a little better.       

--Josh