Tornadoes in Southwest Kansas possible on 4/22. Interesting setup tomorrow… the NAM has begun a trend bringing the warm front farther north into western Kansas like what the GFS and the ECMWF has been showing the past couple of days. I was worried that the low stratus would keep most of western KS shrouded in a more stable airmass… limiting CAPE and potential for widespread severe this far north into southwest Kansas. Well, the 22/00z NAM has quite a bit more CAPE farther north… at the nose of the 500mb speed max… with pretty impressive cold advection at 500mb. 850mb winds will ramp up to around 40+ knots from 00z to 03z with wild low level hodographs from Dodge City south into the eastern Texas Panhandle. This is a favorable environment for late evening tornadoes. The only limiting factor for significant tornadoes will be quantity of low level moisture…. with dewpoints likely at or below 61°F. Other than that, the pattern looks fairly vulnerable to tornadic storms in the 00z to 03z time frame.
Below is an IDV four-panel of the 22/00z NAM model valid 03z April 23 (10pm Central Time the 22nd). Looking pretty darn impressive… and a long evening at work perhaps for me on overtime, as I’m on a day shift at WFO Dodge City tomorrow… so no storm chasing for me. Good luck to all the storm chasers heading out…
3.0″ total snowfall as of 2:45pm… and likely no additional accumulating snow. This will probably be the last post regarding the meteorology of this event. On water vapor imagery, it certainly appears the primary mid level vorticity max (denoted by the red “X”) is tracking a bit farther to the north. This has kept Dodge City dry after the last band moved rapidly through around Noon. Classic dry intrusion… actually two of them (denoted by the yellow arrows). Much farther to the south where the major dry intrusion is ejecting out into Texas, a significant wind storm is occurring with widespread 60 to 70 mph winds being reported in gusts across West Texas. Guadalupe Pass is even experiencing some 100 mph gusts at times. As of the valid time of the surface charts below, the surface vorticity center was located near Coldwater, KS. Nice surface baroclinicity with 11°F at Springfield, CO (far southeast CO) and 62°F at Lubbock, TX. Fascinating storm system, even though I pretty much got shafted here in Dodge City as compared to other snow lovers northeast of here!
2.8″ as of 11:30am. I went out and shot photos around the house, including my neighbors awesome Sante Fe style home. As of 11:30am, I measured 2.8″ uniform on the driveway. Wind continues to be very weak, which is unusual for western Kansas snows. Below is a photo of my awesome red dumpster amidst the snowfall:
2.2″ snowfall as of 7:00am. The dry intrusion has hit… and it is only snowing very lightly at this time. There is an even 2.2″ of accumulation on the driveway. There really isn’t much wind to speak of either. The worst of the wind will occur later this evening once the low moves east of here, but by that time falling snow is expected to be long gone. We may see another inch or perhaps 2″ as the next surge comes out of northeastern New Mexico… so a final of 3 or 4″ is probably reasonable for Dodge City. I may take a few photos around the house later on today… but I’m going to catch more sleep for now.
Well it is inevitable. The dry intrusion is approaching. It is through Liberal. Just ahead of it, though, snow is moderate. Another burst of snow may occur around midday as the main vorticity max (red “X” in the image below) passes just to the south of Dodge City, however I’m not holding much hope out of that. It looks like another quarter inch of accumulation has occurred since I went out and measured at 4:30. I’ll take my official CoCoRaHS measurement at 7:00am. I think 2-3″ is all we will get for a storm total here in Dodge. There is no escaping the dry intrusion.
I woke up at about 4:20am to find 1.2″ of new snowfall since midnight at my house which is 5 N downtown Dodge City. Looking at radar, it appears most of this fell in the 2-3am hour as a healthy east-west band of 24-28dbz echoes moved northeast through Ford County. The 3-5″ forecast still looks to be on track as some good looking radar echoes are still coming up from the southwest all the way back to Guymon, OK. Dry intrusion appears to be showing up, though, southwest of Guymon into most of the Texas Panhandle, which is a bit worrisome for later in the morning. Hopefully that will not shift north very much… and there is hope that it will not based on the track of the mid-level vorticity max as mentioned in the previous post. Will take a look at the latest RUC progs here in a bit.
This is another interesting mid latitude cyclone case involving a compact, potent mid level jet streak. Since the jet streak and mid level PV anomaly is so compact, the greatest lift and heaviest snow may lie a little bit closer to the actual mid level vorticity track than is usual. The chart below depicts the latest NAM model 15-hr forecast of 500mb height/wind and I noted the vorticity max in a red “X”. The arrow then depics the primary 500mb vorticity max…expected to track due east (instead of lifting northeast) as it crosses the plains. This is important in the sense that the heavy snow track could very well be tucked a bit closer to the vort… including Dodge City. Of greatest interest for heavy snow will be the 6-8 hour period from roughly 12z to 20z (6am to 2pm). This is when the mid level vorticity max will be tracking from roughly Gallup, NM to Gage, OK. 3-5″ of snow is a solid bet for Dodge City, and if the vorticity max tracks ever so slightly farther south… like even 40-50 miles… then there could be even heavier snow for Dodge City. It will be interesting seeing the latest RUC model trends overnight! I won’t sleep much, I love the anticipation of heavy snow and the compact mid latitude cyclones that cause them. Call me a meteorology freak I guess. Or weather weenie.
The latest RUC model solutions seem to suggest that persistent 2 and 3-star snows should begin around or shortly after midnight here in Dodge City. Both the Amarillo and Dodge City doppler radars are showing widespread precipitation in the 7,000 to 21,000 foot layer in the troposphere… There are only a few periods so far when some of this heavier snow aloft briefly reaches the surface. Below is an excellent example of the radar revealing snow in this layer (a characteristic donut-hole appearance around the radar site) as the radar beam shoots through these altitudes as the radar beam travels away from Dodge City. I annotated approximate range rings at the point where the radar beam enters the precipitation at about 7,000 foot elevation (roughly 25 miles downrange) and exits the precipitation-bearing cloud at approximately 21,000 foot elevation (roughly 70 miles downrange). My updated thinking for total snowfall here in Dodge City is 3-5″ with the heaviest occurring between 6am and 3pm Tuesday.
Interesting storm shaping up for the Great Plains…impacting much of Kansas, particularly along and north of I-70 late tonight and Tuesday (December 8th). I wasn’t going to blog about this storm because it didn’t appear as if it would impact southwest Kansas much… including here in Dodge City… but trends are just a bit farther south with the lower tropospheric response and precipitation. The arctic air protruded farther south down the western Plains than any of the models suggested. See the map below, which is a surface chart valid this afternoon at 2:00pm:
The surface winds in the arctic air will try to veer around in response to cyclogenesis in the Rockies, but it is difficult. Each model run has trended just a bit farther south with the track of the surface low in time…taking it now into the TX Panhandle then into north-central Oklahoma…which would place heavy snow track from roughly Ness City to Hays to Salina and points northeast from there. Any farther south and it would put Dodge City in the heavy snow track…but as it stands now, Dodge City will be on the southern periphery of this storm. Below is the Snowfall run-total accumulations from the 12z model runs of the GFS and the NAM (from Earl Barker’s site):
Below is the Canadian GEM model valid 6pm CST Tuesday 12/8/09:
I am expecting 2-4″ here in Dodge City, mainly falling between midnight tonight and noon Tuesday 12/8. That said, we will be near or within the gradient in snowfall… so we may get a lot more than that… or not much at all — the higher confidence in heavy snow is going to be up along I-70… as it has been looking pretty much all along. We shall see! With the colder airmass than anticipated, things may wind up being farther south! I’ll be at the house watching it unfold tonight and tomorrow before going into work at 4pm Tuesday.
Mike U
My sudden mid-afternoon pessimism regarding the "cold-core" setup across south-central Kansas yesterday was realized. Storms did develop in the target area as mentioned in the forecast blog posts, but none of them were tornadic based on any reports. I say "based on any reports", because between 2205 and 2215 UTC (5:05 and 5:15pm), KICT WSR-88D revealed a very interesting, very small scale shear couplet with at least 3 volume scans of temporal continuity. The 2210 volume scan revealed what I believe is a TVS signature about 6 miles northwest of Goddard. It was only on one volume scan, and the entire shear signature was gone after 2215 as it evolved very quickly. Was there a brief tornado here? That brief TVS was only 11 miles from the KICT radar (with the center of the beam hitting an altitude of only ~ 500 feet above radar level at that range), and since the storm was so close to the KICT radar, the reflectivity looks unorganized and messy at best. A look from KDDC at that time revealed a 50dbz core extending up to about 20 thousand feet above this area. That brief TVS was interesting to say the least and is very convincing given temporal and even elevation angle continuity. Whatever happened, happened fast, probably less than a minute, and since there were no chasers out there that I know of west of Wichita at that time, if an event occurred there, it probably wasn’t observed. Who knows. I’m not aware of any damage reports from this location. See the 3-image composite below:
Storm chaser Dean Cosgrove sent me a couple links to images he captured of a well-defined funnel cloud from one of the storms along the occluded front in northeastern Pratt county near Preston at around 2135 UTC (4:35pm CDT). Below is one of the images.
Why weren’t storms more productive tornado wise? This is very difficult to answer with any degree of confidence since I haven’t done an in-depth post analysis of the event yet, however I think that southwesterly dry winds were converging too close to cooler northeasterly winds just to its north. There wasn’t a wide enough favorable airmass in between the dry southwest winds and cool northeast winds for storms to thrive long enough in order to take advantage of the rich ambient vorticity that was around. I think storms simply became undercut too quickly by cool northeast winds that resided immediately north of southwesterly surface winds. There really wasn’t much of a corridor of easterly or southeasterly winds (all that’s needed is about 20 to 40 mile wide corridor based on my experience from 26 October 2006 and 10 November 2008), and on 9 April there wasn’t even that, I don’t think. Again, I will have to look at the mesoscale data in order to help answer this. I also think the advancing cold front from the northwest was too much for the surface-based storms as well. Intense convection simply didn’t last that long. I also think this event lacked "converging boundaries". Both on 10 November 2008, and 26 October 2006, it was interesting to see on satellite imagery hours before the event occurred, the presence of cumulus cloud lines marking surface boundaries…which ultimately converged on one another in a constructive manner favoring tornadogenesis. I don’t think this occurred yesterday from what I saw in the data. I think this may have to do with the positioning/evolution of the 400mb PV anomaly. On 10 November and 26 October, the 400mb PV anomalies were very focused and even more mesoscale than yesterday. Yesterday’s 400mb PV anomaly was broader as it moved east, leading to a much broader surface response in the wind field. I don’t think the vertical vorticity axis was tightly concentrated over one specific area, but was rather strung out all along the occluded front without much room for storms to take advantage of before becoming overwhelmed by either chilly northwest surface winds or northeast surface winds. I’m thinking out loud here, but these are my early impressions on yesterday. These are very mesoscale details that make a huge difference in whether a "cold core" event is productive or not. This kind of detail can not be forecast with much ease at all. I more than likely would have busted yesterday had I chased, as I targetted Kingman. Congrats to Dean Cosgrove for at least intercepting something somewhat interesting from one of these short-lived storms.