High Plains Drifter


disclaimer:  "The meteorological views/forecast thinking expressed are those solely of the author of this blog
and do not necessarily represent those of official National Weather Service forecast products,
therefore read and enjoy at your own risk and edification!"

December 21, 2009

Great Plains Christmas Eve 2009 Blizzard [post 1]

Filed under: Dec 23-24, 2009 — Mike U @ 8:24 pm

…Potentially major, long duration blizzard to affect portions of Kansas and Nebraska!…

I decided to blog about this event since there will likely be impacts in Dodge City…including at least 3-6 hours of blizzard (or at least near-blizzard) conditions.  I am working 10pm to 6am forecast shifts right now at WFO Dodge City — my last one being Wednesday morning.  This is going to be a very, very close call for Dodge City regarding major blizzard impacts.  It is still 60 to 72 hours from the major impacts from this storm, so there is plenty of time for models to change…but there is now VERY solid agreement among the major models regarding this storm… which will be a TRUE blizzard…for a good portion of the Central Plains.  Below are a few charts to start off this meteorological documentation of this event:

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Water vapor image showing the mid level moist and dry regions that correspond to areas of lift and subsidence.  Black arrows denote the upper level jet cores.  I highlighted the subjectively analyzed Potential Vorticity (PV) stream in red.  This is the making of the storm.  This PV stream will continue to dig south-southeast…reaching a base somewhere over Arizona tomorrow, December 22nd.  Cyclogenesis will then begin as the mid level jet streak rounds the base of the carved out trough.

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Here is a sample of some of the major model predictions on what to do with the mid level vorticity and height pattern once the PV stream reaches its southernmost point.  Timing is still a huge issue, and history has taught us High Plains winter forecasters that “slower and deeper” is the way to go.  Right now, that would be the UKMET model.  It is farthest southwest with the main PV and 500mb low center valid 00z Thursday Dec 24.

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And then there was the wind.  The ECMWF and UKMET models are depicted here valid 12z Thursday Christmas Eve morning.  A ~998mb low vs. a 1034mb high from the southeast Plains to the far northern High Plains is a classic SLP pattern for western Plains blizzards historically.  The yellow dot on the two charts above denote Dodge City — firmly in the SLP gradient at this valid time.

More later.  I go into work at 10pm, and while I am at work I will not blog since I have to do my professional forecasting of this event for the 27 counties of Southwest Kansas we are responsible for.  Next update will likely be early in the morning or perhaps one more before I go into work this evening.  -Mike U

December 13, 2009

Chase Acct: August 19, 2009 (Northwest OK)

Filed under: Chase Accounts,Latest Chases,Storm Chasing — Mike U @ 11:17 pm

…Woodward Late-evening Supercell…

(originally written August 20th for a storm chaser forum, slightly edited/uploaded to blog December 13th)

August 19th was a rather interesting day.  After the tornado watch conference call with the Storm Prediction Center at work, shift was over and I left DDC at about 4:15pm and headed down to a clumping Cu field in Woods/Alfalfa county. When I first left, a nice hard tower was evident distant southeast and when I looked at radar and saw the blips wayyy the hell southeast close to Enid, I thought this was a fool’s errand.  I got gas in Greensburg and contemplated heading home. I then noticed some agitated cumulus to my southwest. Observations showed southwest winds all around northwest OK… yet dewpoints were in the 65 to 67 degree range. Even with a southwest surface wind, there was still excellent deep layer shear across NW OK with the impinging upper jet streak from the northwest. It became clear as I was driving south toward Hwy 64 that the outflow boundary towers were just not doing it. I was rather surprised that I didn’t see atom-bomb city going on southeast. I wonder if there was a mesoscale gradient in convective inhibition (CINH) there that was just too much for the Enid towers as they were advected downstream to the east? Were these towers/plumes moving east or southeast? If they were moving due east, they would have crossed the boundary at a sharper angle and succumbed to the CINH faster… just not enough time to get that deep sustained moist convection process “jump started”.

These were the things that were actually running through my mind as I was watching this unfold from a distance to my southeast. Meanwhile, to my southwest, the boundary layer was deeper with lower 0-3km static stability and thus easier to “jump start” deep, moist convection. It’s all about initiation, and the direction of motion of towers once they initiate. Regarding that Enid area failed initiation, it just seemed to me that once plumes went up, they crossed the boundary and the strongly backed winds were doing a number on the “jump starting” process. Nice backed easterly winds are great once you have a well-established storm, obviously. What if the towers formed 20 miles farther west…such that they had more time to accumulate growth…before interacting with the higher CINH easterly flow east of the OFB? It could have been a much different story perhaps. I’m just thinking out loud here.

When I got to Hwy 64, I drove west and thought that I could get a good storm going around Harper-Ellis County, OK given the uniform lower static stability in the lower troposphere + CAPE still around 3000 J/kg. 800 to 1000 foot higher elevation also helps in this department for convective initiation… which is why I usually favor farther west for storm initiation. I’ve seen this song and dance before — fantastic looking soundings, good convergence, parcel theory suggesting CINH < 25 Joules… yet still nothing. In almost all these cases, there seems to be too sharp of a potential temperature gradient with initial storm motion vectors taking initial plumes into the cooler pot temps too quickly…and you just end up with anorexia.

Oh yeah, the northwest of Woodward storms were pretty photogenic. Saw a wall cloud at sunset northwest of Woodward, some incredible crepuscular rays radiating through a storm tower (the soon to be Woodward supercell)… there were actually two side-by-side initially.  The images below show the initial towering cumulus stage with the northeastern storm developing a nice structure toward sunset.  The western storm was the one that eventually took over to the northwest of Woodward, which is what the wall cloud images are from.

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December 12, 2009

Mike Umscheid Photography Top Storm Images of 2009

Filed under: Uncategorized — Mike U @ 3:00 pm

Top Storm Images of 2009

2009 will go down as another highly successful year for fine-art storm photography. While I missed out on a number of tornado intercepts, I managed to record some amazing moments of atmospheric violence and beauty. This album showcases the most special moments of storm photography during the 2009 season. I hope you enjoy this series of images as much as I had recording them.

-Mike Umscheid

December 8, 2009

12/8/09 Winter storm: mid-latitude cyclone maturing over Central Plains

Filed under: General Weather & Forecasting,chase mode updates — Mike U @ 4:01 pm

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!

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12/8/09 Winter storm: Snow ending across southwest KS

Filed under: General Weather & Forecasting,chase mode updates — Mike U @ 1:15 pm

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:

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12/8/09 Winter storm: 2.2″ snow at the house (5 N Dodge City)

Filed under: General Weather & Forecasting,chase mode updates — Mike U @ 8:52 am

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.

12/8/09 Winter storm: Dry intrusion approaching. Ahh!!

Filed under: General Weather & Forecasting,chase mode updates — Mike U @ 7:12 am

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.

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12/8/09 Winter storm: 1.2″ snowfall since midnight at my house

Filed under: General Weather & Forecasting,chase mode updates — Mike U @ 5:41 am

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.

December 7, 2009

12/8/09 Winter storm: Snow reaching the ground… Heavy snow track won’t be too far north!

Filed under: General Weather & Forecasting,chase mode updates — Mike U @ 11:50 pm

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.

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12/8/09 Winter Storm: Snow to begin in earnest shortly after midnight

Filed under: General Weather & Forecasting,chase mode updates — Mike U @ 9:44 pm

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.

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