Archive for the ‘Forecast’ Category

This is the latest output from the SPC RUC model.  0-1km EHI values are in the 4-6 range across much of Arkansas, North Mississippi and Alabama this evening.  Effective shear values of 500 m*2/s*2 also suggest very strong turning of the winds in the lower levels and could set off a few tornadoes later this evening into tonight.  At the surface….a meso-low of 1004mb may be forming in SW Arkansas by looking at the mass fields.  I would keep the weather radio on in West Alabama tonight just in case some storms do break out ahead of the front and get active.  Don’t be surprised to see some severe storms tomorrow as well with the front hanging around.  Wind/Hail are the main threats, but a tornado could happen too. 

We will watch the situation and post up more information if needed.  We may even chase locally if something breaks early in the morning hours tomorrow.

We will have a full radar summary and video log of our tornado outbreak on last Friday, April 15th online very soon!  Stay tuned.

Brett

Friday looks to be an active day in the weather department and likely in the field for us during the afternoon and evening hours.  The models are keying in on a rather impressive setup for super cell thunderstorms  and potential tornadoes especially across West Alabama beginning around the 2-3pm time frame.  Computer model guidance over the past couple of weeks has been all over the place….however, the models continue to come in more impressive with every run in regards to Friday.  The short term model…..the NAM….appears to be the least aggressive yet still impressive.

This is the latest 12z NAM forecast sounding for 3PM Friday at Columbus, MS.  You can see that low level moisture and CAPE values are more than prime for tornados.  Keep in mind, this is the LEAST impressive model….and these parameters could be underdone somewhat.  It looks like the threat will get cranking shortly after noon for parts of Mississippi and moving into West Alabama shortly after.  This threat will continue into the evening and overnight hours across portions of our area.  The thermodynamic profiles will support the severe weather threat as it moves eastward and as night falls.  We all know how these systems tend to be once they get to our area during the overnight.

We will be out chasing on Friday and will have two tourists seats available for this event at a first come, first serve basis.  If interested, please shoot me a message on facebook or to our company email address.  alabamastormtrackers@gmail.com 

Stay tuned for more information on this storm system as data flows in.

Well, there are a few parameters that support an increasing threat of damaging winds coming into the state later on Monday afternoon and evening as the cold front begins to push through the area.  The latest 12z NAM that has just come hot off the presses continues to emphasize that the atmosphere will grow unstable in the late afternoon into the evening across central/southwest sections of Alabama ahead of the cold front.

LI values in the –3 to –7 range (higher values to the SW) will support a threat of damaging winds with the increased forcing moving in from the west.  Low level shear values will also support updrafts that will keep the line charged across the state, but directional shear will be nearly non-existant.  We will have to watch for kinks in the line for minor spin ups, but the possibility is near zero.

This NAM reflectivity product does just what we think and suggests a line of showers and storms will move through the Birmingham metro during the late afternoon and push through the area during the evening.  Damaging winds up to 65 mph, small hail, and a VERY slim chance at a brief tornado touchdown are possible.  Main threats will be from the wind, lightning, and heavy rainfall.

We have posted up a slight risk of chasing if something does happen to pop and get significant…..especially ahead of the line but we don’t expect much.  Stay tuned for later updates if the situation deserves a closer look.

We will be chasing Mississippi and Alabama tomorrow as a major storm system moves toward the east.  We expect to depart by 6am Central on our trek to a target of around Oxford, Mississippi.  We expect a line of severe thunderstorms to impact the area with the potential for some supercells to develop ahead of the main line by the Noon – 2PM time frame.

Some of the latest data is indicating the potential for some supercells capable of producing tornadoes….in particular the 18z GFS and the 12z WRF.  Here is a shot of the reflectivity for 20z tomorrow from the 12z WRF.

This model indicates some isolated development just west of Tupelo which moves towards the NE quickly as the line to the west intensifies.  We think this is a likely scenario where a few rogue cells are able to fire ahead of the line before the winds veer too much and surface convergence is killed before the line plows full.  We expect some pretty significant winds as well with the line which could cause sporadic major damage.  The line won’t be something to take lightly. 

The GFS shows extreme divergence fields over portions of MS/AL by the afternoon and temperatures jumping into the 80°s.  Instability values will be moderate to strong and this will help create a volatile environment.  

LIVE STREAMING VIDEO: CLICK HERE!

The live video will be available via the link above at StormScapeLIVE.com.  We will be streaming beginning around 7am as we move toward the target zone.  As of now, we have one tourist along for the ride tomorrow and have one slot open.  If interested….contact us on our facebook page HERE!

Continue to monitor our twitter feed on the side of the page and our fan page updates when on the road tomorrow.  We will pop in and out of our chat room on the right side of our video stream to chat with you guys as time permits.  See you tomorrow.

The Storm Prediction Center has outlined much of the deep south on Monday and Tuesday for the potential for a significant severe weather threat including hail, high winds, and the potential for some strong tornadoes.  This looks to be the greatest severe threat of the year as we move onward into spring with April marching right in and on cue.  There have been some timing differences, but currently the greatest threat and time for severe weather looks to come between 6pm Monday and 6am on Tuesday.  This has the potential to be a dangerous event.  We will continue to monitor and update later on as conditions warrant. 

It looks like we have a more active period of weather ahead for the coming days as we go into the weeks end.  Some isolated severe storms are expected over OK/W AR tomorrow evening as our initial impulse begins to kick out.  Storms will start firing late in the evening over OK and AR and continue to spread eastward into the night and during the day on Saturday.  The SPC has issued a SLGT risk (shown above) across portions of the deep south for Saturday.  The risks look to be mainly damaging winds and large hail, but wind profiles do support some isolated super cell development that would include tornadoes if they form.  We will likely hit the field early Saturday morning if this is to occur. 

The chances decrease somewhat on Sunday, but there is still some chance of severe weather even then.  Our final impulse will roll through on Monday evening with another heightened risk of severe storms.  Tornadoes could be more common with this impulse as wind profiles look better and surface instability is in place.  We are still 5 days away from this shot, so we will get through Saturday first and then have a better determination of Monday’s system.

Heavy rains are beginning to spread northeastward across portions of Central Alabama with the heaviest over southwestern sections of our viewing area in the Sumter, Greene, Perry, Hale, Pickens, and Dallas County areas.  Some areas of localized flooding have already been reported with the rainfall during the afternoon with earlier storms due to swollen creeks and streams from the last widespread rain event a few days ago.

Rain is expected to spread and intensify across the entire area with some of the rainfall being convective in nature.  Most of the region will see a good 2”+ rainfall event from this with more coming tomorrow.  Flash flood watches are already in effect and warnings are quite possible if this event becomes prolonged.  Rainfall will be moderate to heavy for most areas during the night tonight.

There could be a break in the action ahead of the cold front tomorrow before more showers and storms impact the area.  This will be key in terms of how much instability develops across the area and we will be monitoring this frontal progression throughout the night time hours.  CAPE values are climbing to our south in a hurry just south of the front…..on the order of 2000 joules of MLCAPE.  If these kind of values end up progressive into Alabama….we will have a definite severe storm and tornado threat.  We will keep you updated…

Storms are increasing this afternoon on the warm conveyor belt aloft north of the warm front.  This is causing some storms to develop with some hail in the strongest updrafts.  These storms don’t have the potential to become tornadic due to no low level instability.  These cells are all elevated in nature.  Heavy rainfall could become a problem by later tonight and a Flash Flood Watch has been placed for much of the area. 

we continue to watch the potential for some severe storms on tomorrow as the slight risk has been nudged northward again toward the Montgomery area.  Damaging winds and isolated tornadoes look to be the main threats due to the moist environment ahead of the system and high low level shear values.  Heavy rainfall could be the biggest threat of everything with this system.  We will continue to monitor it.

Looks like we will get started fairly fast this weekend with showers and storms already taking place across a good portion of the lower Mississippi Valley this evening.  Tomorrow….some localized areas of flooding are possible ahead of the cold frontal boundary as pockets of heavy rainfall setup during the day.  Some isolated severe weather will be possible in areas where instability values can creep up, but a good chunk of Alabama will deal with easterly winds of the wedge boundary which will keep temperatures cooler east of I-65 and instability in check.  The best chance of any severe storms will be to the west and south over portions of coastal Mississippi, Louisiana, and Alabama where some marine air could spark some severe weather. 

Model output does indicate some areas receiving over 3” of rainfall north of I-20/59 during the overnight tonight and day tomorrow.  With the drought stricken conditions across a good portion of the area, flooding will not be a widespread problem unless some 5”+ totals are reached in a 12 hour period.  This does not look likely, but we will definitely watch the trends and training of cells within the rain shield.

We are beginning to worry a little more about Wednesday as a very dynamic system will take shape to our west and put is back in the warm sector yet again as a cold front heads our way.   There are questions regarding the timing and moisture quality that returns ahead of the system.   If things continue to trend toward more return flow….we will likely be dealing with a tornadic type event.  Stay tuned as we will be updating the chase status during the next couple of days to reflect on this.  Enjoy your wet start to the weekend with a movie and some relaxation like I am.