A cutoff low sits and spins near the NM/CO border for several days, bringing some risks for flash flooding by late Saturday due to very heavy rain and training storms. Severe storms seem a pretty good bet on Friday, with a few tornadoes possible in the 5pm to 10pm time frame. Large hail would be the main threat from the storms on Friday afternoon and evening.
It looks like the models that are in most agreement are staying fairly consistent day-to-day. If I chase tomorrow, my target zone hasn’t changed much. If anything it has moved south a bit…yesterday I’d have put Lakin in the southern portion of the tornado risk area, now I’d put Ulysses in the equivalent location.
Moisture forecasts have improved
The peak value highlighted in the graphic is located pretty close to where the 47 listed in yesterday’s briefing was. An increase of six degrees in the dew point is fairly significant in the high terrain west of Garden City.
Also of note is the wind barbs from near Syracuse to south of Elkhart. From Syracuse to Ulysses the wind is forecast to back (be more southeasterly) than at other locations along the dry line. That backing persists to the next grid point west, just west of the CO border. Backing low level winds tend to help any tornadoes get going.
Combine the backed winds with the higher dew points, and I’m liking a box bounded by Highways 25, 27, 96 and 56…an area that includes Tribune, Leoti, Syracuse, Lakin, and Ulysses.
For comparison, here is another model’s forecast for the same parameters at the same time. It moves the better moisture a bit south and would tend to favor areas from US-50 down to US-160 or so.
This model also deepens the low somewhat and starts to pull moisture back west just north of the Arkansas River. That might be an indication of a developing triple point, which would enhance tornado potential in the Syracuse vicinity.
That said, the overall tornado potential is not that great. I’d expect to see reports of a few tornadoes, not a localized outbreak.
Friday’s Main Storm Risk is Hail
The better moisture gives the potential for larger hail development. Yesterday, when we were looking at dew points below 50, forecasters were expecting hail to peak at about 2″ inches. Now they’re highlighting the risk for half-dollar and larger hail. Because the area at risk is mostly grassland the property damage potential from hail may not be as great as it would further east, later in the year.
Thoughts of note from SPC and others
Here’s the takeaway from the SPC outlook for tomorrow:
Strong heating across the high plains should generally remove the capping inversion by about 21z…revealing around 1000 j/kg MUCAPE from the TX South Plains and Panhandle into southeastern CO and western KS. Low-level winds will continue to back with convergence maximized from eastern CO into the western OX/TX panhandles.
Supercells may be relatively high-based due to only upper 40s to lower 50s f dewpoints…but this dominant storm mode should easily result in large hail as well as isolated tornadoes especially during the evening hrs when dewpoints should be maximized, instability farther W and SRH maximized.
NWS Dodge City is highlighting the heavy rain risk over the weekend more than the severe weather risk Friday:
All of the models are consistent in the large upper low stalling over the far southern Rockies/northern New Mexico region from Friday night into Monday morning. The gulf fetch will be wide open for this event, and a persistent rain looks to really get going by late Saturday and not end until early Monday at best.
NWS Goodland, however, is continuing to highlight the severe potential before getting to the heavy rain risk.
From Friday afternoon into the overnight hours scattered to numerous thunderstorms will develop and move across the entire area. There is a good chance that many of these storms will become severe. The main threats will be large hail and damaging winds. However…a few tornadoes cannot be ruled out.
This combination of thinking is interesting to me, as my target area right now would be in the Dodge City CWA. It’ll be interesting to see how the models line up in tonight’s run. I’m still on the fence about chasing due to the distance, but if I do, I’m leaning much more heavily toward going west on US-50 than on I-70.