8/24/05: FCST: ND

Jul 23, 2004
Iowa City, IA
Chase target:
30 miles west of Jamestown, ND.

Storm initiation 6 PM CDT.

Storm mode:
Medium to high-based supercell storms with hail to 1â€￾.

This morning, UA analysis showed a closed upper-low over SERN Alberta, with a 60+ kt H5 jet max rotating around it and approaching WRN ND. At the surface, low pressure was centered in Saskatchewan with a trough extending SWRD across the WRN Dakotas. Today, this feature will translate slowly EWRD, reaching a Rugby ND to Bismarck line through 00Z, as a new low develops S of Bismarck. Clearing is taking place from SW to NE throughout CNTRL ND. Ample instability will be in place by late afternoon, as a narrow north/south band of mid-60’s dewpoints near and just E of the trough axis, coupled with temperatures around 90 in the target area and H7 temps around 12C, will result in MLCAPE’s to 2000 J/kg. Additionally, deep-layer shear should reach 50 kts with the approach of the aforementioned H5 speed max. SRH’s (0-3km) will increase to 200m^2/s^2 as the SFC low develops in NWRN SD.

- bill