7/1/10 FCST: MT/ND

[Matt Gingery]

Definately a chaseable day today with a 5% hatch for tornadoes per SPC. Return flow pushing west along the Montana upslope coupled with recovery from nocturnal storms should bring CAPE values high enough to support rather robust supercells to develop across portions of E Central and E Montana today. There should be intermountain thunderstorms over western Montana into Idaho, but the main play will be points near Billings and areas to the east and north.

 

[Lanny Dean]

I don't recall ever seeing a 5% hatched area for tornadoes. Interesting.
In looking at the NAM during the 21z through 00z time frame, it appears that 850-500 crossover does not look all that impressive. Certainly instability looks to punch with simulated
LI's nearing -9 to -10 and CAPE values exceeding 1500j/kg as well as decent 0-3km helecity in the order of 400 m2/s2 allthough simulated 0-1 values do not exceed 100 m2/s2 at best. Experience has taught me that generally when 0-1 helecity values are so low in such an environment as this, the tornado potential becomes very low. Current RUC simulate Convective Inhibiton rather high in the area where the best CAPE values entertain the best helecity values. To the east of this area CIN values are almost nill but it may be displaced a little too far east in relation the the strongest CAPE. Either way, certainly looks as though we will/could see a few supercells before a major transition to a nasty mess throughout the area. Current RUC and WRF data suggest that destabilization may be a little slow, much like the 5-14-10 "event" down in the Permain Basin. Interestingly enough that event also yielded a very low 0-1km helecity values and the end result were zero tornadoes within the Basin. It will be interesting to see if the simulated sounding is even close as this mornings did not appear to look all that good. Hopefully we will see a few true tornado reports out of this area (of course out in the middle of nowhere) but I have my doubts...but then again, It really does not matter to me as I wouldn't waste my time or money chasing a minimal event such as this one anyway. Good luck to those are out chasing today though! Hopefully you will get a nice structured supercell.

Lets see what Mother Nature will do today! lol

 

[Justin Turcotte]

I'll be watching extreme northeast ND/northwest MN. Today is a relatively typical ridge rider set-up for the area. Quasistationary boundary in place near the Canadian border, ample moisture from ET and perhaps just enough turning with height to get a storm spinning. Shortwave currently propagating through southern MB may provide just southerly influence/cooling aloft to allow the cap to break. Storms often don't really get going in the area with this set-up/time of year until around 00z. The 12z Operational GFS, Parallel GFS, Canadian GEM, NAM, and15z RUC spit out some convective preip in the area between 00z and 03z. I'd like to see the LLJ back another 20 degrees but beggars can't be choosers.