It looks like we could be in for a brief risk of severe storms associated with strong moisture return ahead of an advancing cold front and stalled dryline on Thursday. Large hail and damaging winds are likely the primary threats, but a low risk of tornadoes seems possible as well.
SREF probabilities depiction of where storms could occur with conditions favorable for tornadoes on Thursday.
What we’re watching: A stout but small shortwave trough will emerge onto the Plains with associated risks of severe weather on Thursday.
- Moisture return is the biggest question mark. Once again this is a ‘just in time’ setup that tends to be more common in the early season. This will limit instability.
- Wind shear is stronger with 0-6km bulk shear values over 50 knots.
- 0-1km SRH (a factor we look at for tornadoes) is around 200 m2/s2 in the afternoon. This is sufficient for tornadoes, depending on storm mode and moisture quality.
- Any time you have rapid moisture return like on Thursday, the possibility of widespread low clouds east of the dryline and ahead of the cold front, limiting overall instability, is there.It’s something to watch.
- Storm mode will be a question mark as well. It looks like a lot of forcing arrives at once, which may cause storms to form in a crowded manner. The shear and instability space is such that this might be truly detrimental to supercell tornado risk.
Both the Euro and GFS have a lot of storms forming during the afternoon hours.
The bottom line: We’re watching this one closely, but right now we’re taking a cautious approach. This appears to be a lower-end setup at this time but that can always change! Any time you have setups in March, a couple of things being less than ideal is enough to keep the severe threat tempered. Another thing to watch is how fast the front crashes on Wednesday. Despite showing some slower solutions last night, the GFS and NAM both are crashing the front pretty strongly during the day (and both have weaker drylines). This could result in a strongly forced line along the cold front forming in the afternoon and moving quickly south and east.
Stay tuned!
