High Plains Drifter

Well… it didn’t take long to fully swing into spring… with the March 30th severe weather event in central/eastern KS-NE-OK and what looks to be an ominous looking tornado setup in Southwest Kansas tomorrow, April 1st.

I’ll let the GFS 4-panel model graphic (a 36-hr forecast valid 6pm CST April 1) below do the talking, for those of you who know how to interpret these charts. About as classic a setup as you can ask for in early spring. A negatively tilted upper trough slowly moving into the high plains at the peak-heating of the day. A formidable dryline will shape up from Western KS into the eastern TX Panhandle. Just amazing wind shear at all levels with abundant moisture and a warm front lifting north during the day. I’ll be working this one (not chasing), I can’t wait! I love working these kind of events… it’s why I do what I do If there’s significant tornadoes, lets just hope they stay in the open farmland like they’re supposed to out here.

The storm came…. and went on this, the vernal equinox of March 20th. We snowed in Dodge from about 5:30am through most of the day. The snow began to let up in the mid afternoon after about 6″ at the airport. Around 6 and a half inches will the offical total here as it’s still snowing lightly as I type. The most snow fell just north of the strengthening 700mb low from the Sublette to the Garden City area, just as I had discussed might happen based on what the GFS and the other models were showing. Unfortunately, the whole system was rapidly occluding and weakening as the afternoon went on and most of Kansas was left in a large dry slot with only scattered snow/rain showers east of a Dodge City to Hays line. This resulted in a busted snowfall forecast (predicted 10-14″+) for areas northeast of Dodge City…especially heading into portions of central and northeast KS. The upper cyclone underwent fairly explosive deepening early this morning in the western OK Panhandle and as quickly as it deepened and matured… it began the weakening process only hours later. A very dynamic meteorological situation with high bust potential for some forecasters… which indeed did happen. There were forecast successes, though, for western Kansas and much of Nebraska where predicted 8-12″+ amounts did indeed verifiy… with amazing 20″+ amounts in Central and Northern Nebraska since Saturday night.

Well just as planned, we changed over from the sleet mix to all snow at about 5:30am. I’m not sure I like the radar trends… looks like a dry slot is rapidly advecting north out of northwest Oklahoma towards southern Ford County. Hopefully this will keep filling in, which I *think* it will. I don’t like being on the edge with these things!

at 4:30am, I’m hearing the “tink-tink” of ice pellets hitting my front window… we are getting a rain/sleet mix at this time. We were all rain about a half hour ago. Garden City airport has been reporting snow in the last hour or so. This sleet period should only last an hour or two before a complete changeover to snow. The radar imagery is pretty impressive right now, verifying the models quite nicely up to this point.

Everything appears to be on track for some rather significant snow accumulations for Dodge City and points surrounding in western Kansas. The GFS nailed the ~06z convective burst several runs back, as evident by the regional radar shown here (05z). This is the genesis of the impressive wrap-around warm conveyer leaf as the storm matures overnight just southwest of southwest KS. I still foresee thundersnow in the 12-15z window across southwest KS, including DDC. At the heaviest, snowfall rates may easily exceed 2″ per hour, mainly during the mid-morning hours. All versions of the RUC model (including the development RUC on the FSL/RUC webpage) through 12 hours show a significant amount of QPF through 18z (noon) Monday. See no reason to doubt this from a simple pattern recognition standpoint with a fully maturing mid-latitude cyclone strengthening along the “golden path” for Dodge City. According to all the model soundings I’ve interrogated, it appears we will change over to snow here in DDC nearly at the onset of the big “blob” of (convective) precip heading northeast towards SW KS as seen on radar. It will initially be a rain/snow mix, but quickly change to a sleet/snow mix then all snow just before 12z. See the Skew-T graphic, a 9hr forecast from the RUC model. Look at the massive warm-advection signature (winds veering with height) in the lower 300mb or so of the sounding! More later. It’ll be tough for this weather weenie to get some sleep knowing what’s coming!

Saturday evening model runs are in. No huge surprises with this run actually. Getting into the day Monday is where the NAM begins to diverge from the slower GFS/Canadian solution. Slower solution pretty much = more snow for here in Dodge City, as I mentioned in the previous post. Here is the 48hr fcst from the Canadian 00z run valid 6pm Monday evening:

This canadian run is actually fairly consistent with the placement and timing of things from the 84hr fcst valid the same time that I posted yesterday. It continues to show a near 1″ 12-hr QPF bullseye near the track of the 700mb low. The “bullseye” in the QPF field is a bit farther northeast than the 84hr forecast, however this is what we call “white noise” in the model details. The main signal of interest is that there will likely be a 1″ QPF hit in a 12-hr period during the day Monday along and immediately north of the 700mb track. The Canadian model is very similar in placement of the 700mb almost along the OK/KS border near Medicine Lodge at 21/00z (6pm Monday). The 00z run of the GFS and the NAM show a rapid cooling of the 800-700mb warm layer from 06z to 12z Monday morning changing any rain over to heavy snow by sunrise or shortly before. When the precip changes over to snow in SW KS near Dodge City, there may in fact be some thunderstorms involved. I haven’t experienced a thundersnow since 1993. This would be a real treat!

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The 18z GFS model is revealing a “best-case scenario” for a major snowstorm in Dodge City. Taken at face value (which is a dangerous thing to do with any model!), the 18/18z rendition of the GFS evolves a very deep, slow-moving, compact 700mb low across far southwest Kansas during the day Monday 20th. Below is a 6-panel graphic I whipped together, graphics taken from the ARL-Ready website. In events like this where deep cyclogenesis is involved, I love to use the 700mb low track for the placement of the heaviest snow with the “meat” of the storm. An old-school heavy snow forecasting tool is the 700mb low track, and to me, in situations with strong 700mb cyclogenesis like in this case, it is a very good tool. Very impressive snow rates can exist with deep, slow moving, and compact 700mb lows. Well, we have a beauty of one showing up in all the models for Monday. The track of it is extremely critical. If the 700mb tracks just north of Dodge, then the Ness City to Wakeeney corridor will get a foot or more of snow. If the 700mb low tracks where the 18/18z GFS suggests, then the areas from Garden City to Dodge City to Larned will get an easy foot… given the moisture at play. The key? A deepening, and crawling 700mb low. That’s how we get the footers here in SW KS. The trends in the model runs continue to support this. This is getting rather exciting!

The huge winter storm is still on track to blitz much of the central plains from southwestern KS into the southern Dakotas. It appears there will be two waves of winter precipitation. The first wave will be developing late this afternoon over eastern Colorado which will expand into northwestern KS tonight and into Nebraska. This wave will produce moderate to heavy snow amounts in central/northern Nebraska into South Dakota. Then the main storm will begin to eject out of New Mexico tomorrow night. The rain snow line will slowly shift south Sunday night from the I-70 corridor down into Southwest Kansas overnight. We will probably change over to snow here in Dodge probably around or shortly before dawn Monday Morning. There will be a warm pocket at 800mb to overcome before we go over to all snow. Just massive warm/moist advection late Sunday night into the first half of Monday. The classic 500/700mb low tracks would actually put the heaviest snows from roughly WaKeeney into north central KS to just north of Kansas City. This is certainly indicated in both the GFS and NAM snowfall outputs, as shown below. This will be one for the books, certainly, for someone in northern KS and central Nebraska. The southern portion of the snow storm, closest to the 500/700mb lows, may see some thundersnow. We will be near the gradient here in Dodge between a ton of snow and not-so-much snow. It’s very tricky. If the 700mb low tracks just south of Dodge, we will likely see very heavy snow for several hours, piling up to near a foot by late Monday. If the 700mb low tracks along or just north of Highway 50, then the I-70 corridor will blitzed. Either way, SOMEONE will see well over a foot when all is set and done. A very nice, and MUCH NEEDED widespread precip event for the farmers all across the central plains!

Here in Dodge City, the total snowfall for the 2005-06 winter season has been around 5.5″ as of today. This is pretty much the case for much of the central High Plains in what has been an extremely dry winter. We have already had two significant storm systems blow through with very strong winds (March 12th; 60 mph wind gusts… 15th; near 50mph wind gusts) causing reduced visibility in blowing dust with a couple of large grass fire events.

What I love about the month of March is that the swing towards spring can throw the planetary scale pattern into a chaotic re-adjustment leading to a wide diversity of possible sensible weather outcomes. March 12th was a perfect example, as a historic tornado outbreak consumed the lower Missouri River valley. As can happen a lot of times in March, the following week’s weather could continue this jump right into spring…or the weather could take a step back into winter. Well, in this case… March 2006… we appear to be following the latter. A very significant storm will be digging into the southwest states this weekend. The huge difference between this storm and and the March 12th storm is the fact that there will be cold air in place across much of the plains out ahead of this large storm… instead of a large warm sector across the plains.

Despite there being an intrusion of much cooler air ahead of this storm system… there will be an abundance of low level moisture advecting from the Gulf of Mexico. This is evident as of the time of this writing (Friday 7pm CST) by the mid to upper 60s dewpoints advecting northward through south Texas.

For about 3 weeks around the vernal equinox…there is a climatological “peak” if you will…for the best juxtaposition of remnant winter cold air and the resurgence of Gulf of Mexico moisture. It is this combination that allows for robust development of synoptic scale extra-tropical cyclones that can cause major winter storms in western Kansas. Looking back at some of the snowstorm records I’ve compiled for Dodge City, KS, 4 of the top-5 snowstorms in Dodge City since the late 1800s have occurred within 2 weeks of the vernal equinox:

• 20.5″ — Feb 24-27, 1903
• 18.5″ — March 22-25, 1957
• 18.2″ — March 12-17, 1924
• 18.0″ — March 9-10, 1922
• 15.7″ — March 12-13, 1999

Other one-foot snowstorms centered around the vernal equinox include March 15-16th, 1970 (12.8″), March 23-24th, 1987 (11.5″). An early spring blizzard in 1938 produced 14.3″ of snow on April 7-8th.

Will we also add March 19-20th, 2006 to the list of one-footers in Dodge City?? The models are painting a very rosy picture in the 72-84hr time frame for a significant snowstorm for portions of western Kansas. It’s still unclear who will really get the bulk of this storm, but there seem to be all the ingredients necessary for a one-foot snowfall for at least a couple locations north of the surface low in western Kansas.

From the 12z model runs… the ECMWF, Canadian, and UKMET models show at least 6 to 8″ of wet snow for Dodge City. The GFS and NAM show the bulk of the precip just north of Dodge towards I-70… like the Wakeeney to Hays areas. Stay tuned!!!

I’m finally getting around to writing about the big Great Plains blizzard early last week. It was essentially a non-event for here in Dodge City, but we really didn’t miss this winter fun but very far… for areas near I-70 in northwestern Kansas were about the southern extent of this far-reaching major blizzard. The storm lasted from roughly mid to late afternoon on Sunday the 27th and continued through the day on the 28th before winding down early on the 29th. Widespread 50 to 70mph winds existed from western Kansas through most of central Nebraska into central and eastern South Dakota. By the storm’s end, the largest snowfall amounts were in the foot to foot and a half range…mainly from north central Nebraska into south central South Dakota. This is also coincident of the strongest winds during the event…where severe blizzard conditions lasted a solid 24 hours at some locations.

A storm chaser friend of mine, Mike Hollingshead (http://www.extremeinstability.com), actually chased and documented the event. You don’t really “chase” these kind of weather events, per se… but just document the events as they unfold near your location. Much like my heavy snow chase along the Front Range in Colorado on October 10-11 a couple months ago.

Some of the towns and cities that took it on the chin with this storm…with blizzard conditions being reported at least 12 hours or so…included Goodland, KS…North Platte, NE…Broken Bow, NE…Ainsworth, NE…O’Neill, NE…Winner, SD…Pierre, SD. This was certainly a large scale event stretching some 600 to 700 miles from northeastern Colorado into the eastern Dakotas. It was a storm that actually unpredicted…to an extent. There was a general consensus some 5 to 7 days ahead of time that there may be a winter storm of some sort…somewhere on the plains…towards the end of the Thanksgiving holiday. None of the models, however, predicted the ferocity of this event until maybe 2 days out…if that. Some of the short term models didn’t catch on to the explosive deepening of the storm until Saturday (26th) afternoon! I bolded Ainsworth, NE above because if there was one town that got about as clobbered as any in this event…it was Ainsworth. See the weather observations below.

Below are some of the awesome observations during the storm (every 3 hours through the blizzard…in coded METAR format).

Goodland, KS >>

METAR KGLD 271753Z AUTO 34023G34KT 1/4SM +SN FG OVC003 01/M01 A2934 RMK AO2 PK WND 35040/1656
METAR KGLD 272053Z AUTO 34034G40KT 1/4SM SN FG BKN003 OVC009 00/M01 A2934 RMK AO2 PK WND 34041/2025
METAR KGLD 272353Z AUTO 34040G51KT 1/4SM FZFG M01/M01 A2938 RMK AO2 PK WND 34051/2353
METAR KGLD 280253Z AUTO 33043G54KT 2SM UP BR OVC030 M01/M03 A2941 RMK AO2 PK WND 33054/0253
METAR KGLD 280553Z AUTO 33032G45KT 3/4SM BR VV014 M02/M04 A2946 RMK AO2 PK WND 34045/0546
METAR KGLD 280853Z AUTO 34036G45KT 1/2SM FZFG BKN009 OVC014 M04/M06 A2951 RMK AO2 PK WND 33052/0816
METAR KGLD 281153Z AUTO 34044G53KT 1/4SM FZFG VV003 M05/M07 A2955 RMK AO2 PK WND 34053/1152
METAR KGLD 281753Z AUTO 34042G56KT 1SM -SN BKN075 M03/M07 A2965 RMK AO2 PK WND 33056/1745
{last observation until 290253Z}

Broken Bow, NE >>

METAR KBBW 272053Z AUTO 35028G40KT 3SM -SN BR FEW013 OVC020 M01/M02 A2932 RMK AO2 PK WND 36044/2007
METAR KBBW 272353Z AUTO 35028G42KT 1/4SM FZFG VV001 M02/M02 A2933 RMK AO2 PK WND 35048/2306
METAR KBBW 280253Z AUTO 34037G52KT 1/4SM FZFG VV001 M04/M05 A2934 RMK AO2 PK WND 36054/0158
METAR KBBW 280553Z AUTO 35039G48KT 1/2SM FZFG VV001 M05/M07 A2934
METAR KBBW 280853Z AUTO 35033G44KT 1/4SM FZFG VV001 M06/M08 A2937
METAR KBBW 281153Z AUTO 34040G58KT 1/4SM FZFG VV001 M06/M07 A2934
METAR KBBW 281453Z AUTO M1/4SM FZFG VV001 M07/M08 A2942
METAR KBBW 281753Z AUTO 34040G55KT M1/4SM FZFG VV001 M07/M09 A2946 RMK AO2 PK WND 33056/1733
METAR KBBW 282053Z AUTO 33027G47KT 1/4SM FZFG VV001 M07/M09 A2952 RMK AO2 PK WND 33051/2031
METAR KBBW 282353Z AUTO 34029G47KT 1SM HZ BKN024 OVC039 M06/M08 A2960 RMK AO2 PK WND 30054/2343
METAR KBBW 290253Z AUTO 33032G41KT 1 1/2SM HZ BKN070 OVC100 M06/M10 A2968 RMK AO2 PK WND 33045/0203
METAR KBBW 290553Z AUTO 33032G43KT 1 1/4SM -SN OVC095 M07/M10 A2978 RMK AO2 PK WND 34043/0551
METAR KBBW 290853Z AUTO 33022G32KT 6SM BLSN BKN026 M06/M10 A2983 RMK AO2 PK WND 34038/0759

Ainsworth, NE >>

METAR KANW 272350Z AUTO 34027G37KT 1SM -SN BKN004 OVC008 M02/M03 A2948 RMK AO2 P0001
METAR KANW 280250Z AUTO 33033G41KT 1 1/4SM -SN BKN012 OVC017 M03/M05 A2948 RMK AO2
METAR KANW 280550Z AUTO 34035G49KT 3/4SM -SN SCT012 OVC018 M05/M07 A2947 RMK AO2
METAR KANW 280850Z AUTO 34039G47KT 1/4SM +SN OVC004 M06/M07 A2948 RMK AO2
METAR KANW 281230Z AUTO 34042G55KT M1/4SM +SN VV000 M06/M06 A2948 RMK AO2
METAR KANW 281450Z AUTO 33034G51KT M1/4SM +SN OVC001 M06/M07 A2950 RMK AO2
METAR KANW 281750Z AUTO 33043G53KT M1/4SM +SN BKN001 M07/M08 A2954 RMK AO2
METAR KANW 282050Z AUTO 33035G49KT M1/4SM +SN OVC001 M07/M08 A2956 RMK AO2
METAR KANW 282350Z AUTO 32032G44KT 1SM -SN VV007 M06/M07 A2963 RMK AO2
METAR KANW 290250Z AUTO 32029G40KT 2 1/2SM -SN CLR M06/M09 A2972 RMK AO2 VIS 1 1/2V4

Pierre, SD>>

METAR KPIR 272353Z AUTO 34023G30KT 7SM OVC013 M04/M07 A2964 RMK AO2 PK WND 33032/2303
METAR KPIR 280253Z AUTO 33024G31KT 1/2SM SN FZFG VV004 M05/M07 A2967 RMK AO2 PK WND 33033/0222
METAR KPIR 280553Z AUTO 33025G33KT 1/2SM FZFG BLSN VV003 M06/M07 A2966 RMK AO2 PK WND 33038/0535
METAR KPIR 280853Z AUTO 34034G42KT 3/4SM BLSN BR BKN006 BKN014 OVC021 M04/M06 A2962 RMK AO2 PK WND 33042/0853
METAR KPIR 281153Z AUTO 33033G45KT 1/4SM +SN FZFG VV003 M06/M07 A2965 RMK AO2 PK WND 33048/1115
METAR KPIR 281453Z AUTO 33036G45KT 1/4SM FZFG BLSN VV003 M07/M09 A2967 RMK AO2 PK WND 33052/1422
METAR KPIR 281753Z AUTO 33033G46KT 1/4SM FZFG BLSN VV011 M07/M08 A2966 RMK AO2 PK WND 33049/1704
METAR KPIR 282053Z AUTO 32033G46KT 1/2SM UP OVC040 M06/M08 A2967 RMK AO2 PK WND 32046/2049
METAR KPIR 282353Z AUTO 32031G42KT 2SM BLSN OVC085 M06/M09 A2973 RMK AO2 PK WND 32044/2259
METAR KPIR 290253Z AUTO 33030G40KT 3SM BLSN FEW030 BKN110 M07/M11 A2979 RMK AO2 PK WND 32041/0201
METAR KPIR 290553Z AUTO 32027G35KT 5SM BLSN FEW024 OVC030 M06/M10 A2984 RMK AO2 PK WND 33037/0521

What was even more unprecedented were the observations out of the automated weather station in Ainsworth, NE. They reported continuous 20-minute observations through the duration of the event amidst incredible blizzard conditions. This station actually reported “M1/4 SM” for 10 solid hours! This is interpreted as “visibility below one quarter of a mile”. In other words, likely zero or near zero. It is unusual to see an automated weather observation report M1/4… let alone for 10 straight hours… every single observation during the event. Wow. Note all the “+SN” observations. This is interpreted as “Heavy Snow”, but this is more than likely extreme blowing/drifting of snow and actual snowfall may not have been heavy at all for some times. Here are those obs: (look at those winds!!…in bold are winds >= 50kts or 58mph)

METAR KANW 281230Z AUTO 34042G55KT M1/4SM +SN VV000 M06/M06 A2948
METAR KANW 281330Z AUTO 33043G57KT M1/4SM +SN VV000 M06/M07 A2950
METAR KANW 281350Z AUTO 33040G56KT M1/4SM +SN VV000 M06/M07 A2950
METAR KANW 281410Z AUTO 33043G53KT M1/4SM +SN VV000 M06/M07 A2950
METAR KANW 281430Z AUTO 33040G52KT M1/4SM +SN VV000 M06/M07 A2950
METAR KANW 281450Z AUTO 33034G51KT M1/4SM +SN OVC001 M06/M07 A2950
METAR KANW 281510Z AUTO 33042G53KT M1/4SM +SN OVC001 M07/M08 A2950
METAR KANW 281530Z AUTO 33041G51KT M1/4SM +SN BKN001 M07/M08 A2951
METAR KANW 281550Z AUTO 33040G54KT M1/4SM +SN VV000 M07/M08 A2951
METAR KANW 281610Z AUTO 33043G53KT M1/4SM +SN VV000 M07/M08 A2953
METAR KANW 281630Z AUTO 33039G49KT M1/4SM +SN VV000 M07/M08 A2953
METAR KANW 281650Z AUTO 33036G57KT M1/4SM +SN VV000 M07/M08 A2954
METAR KANW 281710Z AUTO 33038G52KT M1/4SM +SN BKN001 M07/M08 A2954
METAR KANW 281730Z AUTO 33039G52KT M1/4SM +SN VV000 M07/M08 A2954
METAR KANW 281750Z AUTO 33043G53KT M1/4SM +SN BKN001 M07/M08 A2954
METAR KANW 281810Z AUTO 33038G54KT M1/4SM +SN BKN001 M07/M08 A2954
METAR KANW 281830Z AUTO 33040G51KT M1/4SM +SN BKN001 M07/M08 A2954
METAR KANW 281850Z AUTO 32035G46KT M1/4SM +SN OVC001 M07/M08 A2954
METAR KANW 281910Z AUTO 33037G50KT M1/4SM +SN OVC001 M07/M08 A2954
METAR KANW 281930Z AUTO 33042G56KT M1/4SM +SN BKN001 M07/M08 A2955
METAR KANW 281950Z AUTO 33038G51KT M1/4SM +SN BKN001 M07/M08 A2954
METAR KANW 282010Z AUTO 33036G49KT M1/4SM +SN BKN001 M07/M08 A2955
METAR KANW 282030Z AUTO 33034G48KT M1/4SM +SN OVC001 M07/M08 A2955
METAR KANW 282050Z AUTO 33035G49KT M1/4SM +SN OVC001 M07/M08 A2956
METAR KANW 282110Z AUTO 33037G49KT M1/4SM +SN OVC001 M06/M08 A2957
METAR KANW 282130Z AUTO 33042G52KT M1/4SM +SN OVC001 M06/M07 A2958
METAR KANW 282150Z AUTO 33039G48KT M1/4SM +SN OVC001 M06/M07 A2958
METAR KANW 282210Z AUTO 33035G45KT M1/4SM +SN OVC001 M06/M07 A2959
METAR KANW 282230Z AUTO 33035G48KT M1/4SM +SN OVC001 M06/M07 A2960
METAR KANW 282250Z AUTO 32039G47KT M1/4SM +SN VV000 M06/M07 A2960

I’ve done some research on historical blizzards since 1948 over the past couple of years, and I must say this one stacks up there as one of the true classic large-scale Plains blizzards. Mike Hollingshead was in O’Neill, NE…which is about 65 miles east of Ainsworth. He experienced some incredible conditions. You can read his account and see his images here.