Chase target for November 27
Chase target:
Miami, OK (along I-44 in the extreme NERN corner of the state)
Timing:
Storm initiation around noon.
Storm type and evolution:
All types of severe WX will be possible, including a small tornado threat. Storm motion will be very rapid, with cells traveling to the NE at 60 mph.
Discussion:
An active fall storm system will affect much of the central US with a full spectrum of hazardous WX including severe storms and heavy snow over the next 48 hours. Active WX setup upstairs at 00Z, with 180kt H3 max over NRN CA diving SE towards base of negatively-tilted trough. Several embedded waves were noted, with lead S/WV lifting through ERN NM/WRN TX along with primary wave in exit region of streak now moving through AZ. At the SFC, slow cyclogenesis has commenced in WRN KS. This low begin to rapidly deepen beginning this time tomorrow when the best upper support arrives, and it will take a track through NWRN IA into MN through the day Monday as heavy snow develops to the N and W of this track.
Tonight:
SFC WF extends E from the low along the NE/KS border and IA/MO border. A 60kt LLJ is developing and nosing into WRN IA. Significant moisture and instability, rooted just above the BL, is being advected towards the upper-Midwest. 00Z TOP and OAX soundings both show 100-150mb deep moist layer along with region of steep lapse rates just above a stable layer. Later this evening, H85 WF should bisect IA from NW to SE. Convergence along front, and isentropic lift of around –5ub/S on 290K through 296K surfaces to the N of the front may provide the focus for some elevated showers and storms in NRN IA and SRN MN. No severe WX is expected.
Sunday:
The SFC low will rapidly deepen and lift from NWRN OK into KS. A secondary developing WF along the OK and KS border will provide the focus for severe WX early in the afternoon, while a dryline dives to the E towards the target by mid-afternoon. The resulting triple point will lift rapidly off to the NE with the advance of the DL. As is often the case this late in the season, moderate instability will be coupled with very strong mid- and upper-level forcing and shear. Mid-afternoon MLCAPE’s will generally be below 1000J/kG while deep layer shear to 70 kts in left-exit region of H5 streak will result in very long but only slightly curved hodographs which will support organized severe WX with the primary threat severe wind gusts to 80 mph.
Sunday night and Monday:
Attention will turn from severe convective WX to the first significant snowstorm of the season. Main axis of heavy snow will occur along an axis of deformation to the N and W of the SFC low track in SD/ND/MN.
- bill
A small window of opportunity may be there for extreme E. Ks and W Mo by late afternoon. Point, click and get out of the way, may be the best one can do for this round--good luck to anyone who gives it a shot.
