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!"

April 9, 2011

chase update 4/9 620pm

Filed under: chase mode updates — Mike U @ 6:24 pm

Well, I have gone back south to the Barber-Pratt county line south of
Coats, KS. There is a really healthy towering cumulus field, with
some of the towers generating echoes on radar in the Protection area
to my southwest. Visually, there are three areas close to each other
with very tall towering cu with sharp edges. HOpefully something
emerges from this cluster… and if not, it’s only a little more than
an hour back home. Hoping for some sunset magic!

chase update 4/9 5pm

Filed under: chase mode updates — Mike U @ 5:04 pm

The towering cumulus west of me is not progressing to the next level
of development. I am between St John and Pratt on Hwy 281. There is,
however, what appears to be the makings of a legit Cb to my southwest
on the dryline near Buffalo, OK. This is about 90 miles to my
southwest…. or back toward my original target to the west of Barber
County. I may head back south soon toward western Barber County if a
storm forms down there and the cu up here does not progress in
development.

chase update 4/9 350pm

Filed under: chase mode updates — Mike U @ 3:52 pm

I’ve adjusted my target northward to Pratt-Great Bend. I’m concerned
about the northward advancement of drier air/shallower moisture in
Oklahoma. There is a decent Cu field developing along the dryline
now, and I’m watching some decent vertical attempts to my southwest
from about 8 NE Pratt along Hwy 61.

chase day update 4/9 2:35pm

Filed under: chase mode updates — Mike U @ 2:38 pm

I am parked on the south side of Greensburg along the dryline. South
wind here about 25 mph. There is a significant southwest momentum
surge to the west-southwest of me with winds 35 to 50 mph. I think
this will add to convergence in this area by 21-24z. I still feel
optimistic that a storm will develop along the dryline down here.
There is a cumulus field extending along a north-south line just to
the east of me… in the mid 60s dewpoints. I feel that the better
convergence will actually develop a bit southwest of me over the next
couple of hours and should see towering cu field form… hopefully….
from Laverne OK to Ashland KS or so

April 7, 2011

Full Rainbow, Control Burn, and Small Structured Storm — 7 April 2011

Filed under: Photography — Mike U @ 11:00 pm

As I was out working in the yard after work on Thursday, April 7th, a small storm developed to the southwest of my house with the sound of distant thunder becoming increasingly persistent.  This storm rolled south of me, but in its wake a fairly vivid rainbow appeared off to the east-southeast:

Before this occurred, however, I noticed a plume of smoke behind my neighbor’s house to the east.  I figured this was due to a small control burn of CRP grass on property close to my house.  The control burning conditions were fairly ideal with light winds and very manageable relative humidity.  After that first small storm moved away, I noticed that they were beginning to burn off the small field of CRP grass 1-acre lot away from my house to the north.  I grabbed my Nikon D200 camera with the 80-400mm lens on it and began shooting away.  Shortly thereafter, a few of my neighbors showed up and we all enjoyed a nice little chat as the field was burning away.

Another small storm developed to the northwest around sunset which provided a nice backdrop to the remaining flames and smoke from the burned field.  This storm, obviously very small and rather insignificant in nature, did reveal some fairly clean updraft and rear flank structure!  This was a nice little surprise for being only a short 50 yard walk from my front yard!

Yet another cluster of weak storms formed after sunset, and I drove up north a few miles to try my hand at some lightning-illuminated structure shots.  I did manage a few images of some marginal storm structure from this group of weak, short-lived storms:

All in all, a nice little photo shoot for an evening I was totally not expecting to break out the camera at all!

March 8, 2011

Southwest Kansas Winter Storm 8 March 2011 [4]

Filed under: 2011 Mar 08 — Mike U @ 6:44 am

Sleet showers continued through the night. Warm advection centered around 850mb prevailed through the night, keeping the warm layer aloft in-check, and keeping the precipitation type sleet all through the night (after it had changed back over from the first snow band late last evening).  As of the pre-dawn hours this morning, the highest snowfall totals were 3 to 4 inches from Syracuse to Scott City (see Figure 1 below).  The initial potential vorticity (PV) max (‘x’ #1 in Figure 2) was lifting out into central Kansas as of 1100 UTC (5:00am CST), yielding subsidence now across southwest Kansas, including Dodge City (outside of a few widely scattered sleet showers along and south of the Arkansas River).  The next mid level PV anomaly, anotated ‘x’ #2 i Figure 2, will move south of southwest Kansas later on today, providing another shot at light accumulating precipitation, which will most likely be in the form of snow with cold advection finally prevailing at around 850mb eroding the warm layer aloft.

Figure 1:
20110308-1

Figure 2:
20110308-2

Southwest Kansas Winter Storm 8 March 2011 [3]

Filed under: 2011 Mar 08 — Mike U @ 12:36 am

Major FAIL?!?! Wow.  Leave it to me to start blogging about a potential winter storm to bring the possible failure modes of this system to light.  This is not looking good AT ALL.  That first band of precipitation did produce 0.4″ of snow at my place, but has since ended as of about 10:45pm.  The figure below explains the major failure mode with this system for Dodge City.  I still think a few inches of snow are possible, but significant accumulations appear unlikely, and if it does occur, precipitation will need to reform again to the southwest of Dodge City.

Figure 1 (Illustrating/discussion potential major failure mode for a significant precip event for Dodge City):
20110307-7_0

Figure 2 (08/00z run of the GFS valid hours 6, 12, and 18):
20110307-8

NOTE: As I publish this post, precipitation is trying to form southwest of Dodge City back to the northwest of the major area highlighted in red in Figure 1.  All is not lost…yet!  Precipitation forecasting on the western plains is very sensitive to the little sub-synoptic scale nuances thanks to the “Rock Pile” just west of us.

March 7, 2011

Southwest Kansas Winter Storm 8 March 2011 [2]

Filed under: 2011 Mar 08 — Mike U @ 10:29 pm

Sleet has commenced at my house, 5 N Dodge City. The initial band of precipitation (see Figure 1) began to move in around 8:30pm.  It has been pretty much all sleet up to this point through the time of this writing around 9:30pm.  It’ll be interesting to see how long the precipitation type will be sleet.  There is a disagreement with respect to the warmth of the warm layer aloft over Dodge between the RUC and the NAM.  The RUC is about 1 to 1.5 degrees C warmer and keeps the zero line at 850mb quite a ways northwest of Dodge, whereas the NAM keeps the zero line quasi-steady right over Dodge (see Figure 2).

Figure 1:
20110307-4

Figure 2:
20110307-5

Southwest Kansas Winter Storm 8 March 2011 [1]

Filed under: 2011 Mar 08 — Mike U @ 7:09 pm

Significant, much needed precipitation event headed for southwest Kansas! For the better part of the last week or so, it appeared a major winter storm would affect the western Plains.  Mid to late last week, all of the global spectral model solutions (and to a large degree their associated ensemble members) were focusing on western/central Nebraska…into southern South Dakota for this storm.  By Friday and Saturday (March 4-5), the models were beginning to suggest a more southern track to the storm.  It then became apparent that northwest Kansas into south-central South Dakota would see the brunt of the storm.  Now that the storm is now within striking distance, all models are locked in on a solution with the mid level PV anomaly and evolution, and it really does favor Southwest Kansas for substantial precipitation.  While the placement in the models was always in question, what was a near-constant was precipitation potential with the storm.  36-hr storm total precipitation from the GFS as well as the Canadian GEM consistently showed potential for 1.0 to 1.5″ of storm total precipitation within the “sweet spot”.  Late last night and early this morning’s model runs showed this 1.0 to 1.5″ storm total QPF shifting south to generally a Lakin-Dighton-Wakeeney line… continuing northeast to north-central Kansas and southeast Nebraska.  18z runs of both the GFS and the NAM have continued this southward shift of the 1.0 to 1.5″ axis even further… to roughly a Ulysses to Garden City to Jetmore corridor.  Both the 07/18z NAM and the GFS show 1.0″+ storm total QPF for Dodge City.  It stands to reason now that Dodge City will be included, if not VERY close, to the sweet spot of the storm.

Now precipitation type.  Today, a shallow arctic cold wedge was moving south and was more aggressive in its movement south than any of the models from last night were suggesting.  This isn’t a surprise (early last week’s arctic cold wedge event in southwest Kansas is a classic example).  As I type, the temperature in Dodge City 33 degrees (See Figure 1), and advection on north winds 15-20 mph will continue to lower the temperature through the evening into the upper 20s.

Precipitation in Dodge City will likely commence as some light freezing drizzle later on this evening with more widespread precipitation in the form of freezing rain/sleet sometime around midnight or thereafter.  Huge questions regarding how shallow the cold wedge will be in Dodge City and whether it will be deep enough for the warm layer aloft to be pinched off enough to support all snow (entire sounding below zero Celsius).  I think we will see several hours of accumulating sleet overnight with a change over to snow probably 4-7am or so tomorrow morning.  I took a look at the 12-hour QPF from the 18z run of the GFS ending 09/00z and it showed about a half inch of QPF during this time frame… this would suggest as much as 4-6″ snowfall after the sleet/freezing rain.  Below are some figures I put together

Figure 1:
20110307-3

Figure set 2 (18z NAM model depiction of 700mb RH/Omega, 850mb Temperature):

Figure set 3 (18z NAM model depiction of 400mb Potential Vorticity/Wind Speed, 500mb Heights):

February 27, 2011

Chase Account: 2011 February 27 (Sub-severe storms)

Filed under: Chase Accounts,Storm Chasing — Mike U @ 10:00 pm

First storm chase of 2011 — sub-severe storms from northern Woods County, OK into Barber County, KS

Sunday, 2/27 was my only day off work during a long stretch of day shifts, and I was swaying back and forth on deciding whether to dedicate the day to a storm chase or not.  When I went to bed Saturday Night, I was not anticipating chasing, but was willing to re-consider if things shifted farther to the west.  Well, the RUC and HRRR models early Sunday morning were shifting the surface moisture and convergence farther west into northwestern Oklahoma.  Also, the remnant cold airmass had lingered around a bit farther south deeper into Kansas, and it appeared that the warm front would not lift back north into Kansas at the surface.  The mid level jet streak was also poised to come across West Texas a little bit later and perhaps a bit farther south, so all this led to the possibility of a focus farther west for mid-afternoon strong to severe storms. I decided to target far Northwest Oklahoma based on agreement between the RUC and HRRR model runs, which seemed to be fitting observations and my conceptual model of how the wind, temperature, and moisture field would evolve.  I expected a narrow tongue of mid-upper 50s dewpoint air to make it back to Harper County, OK.

The moisture did make it back into far Northwest Oklahoma by early afternoon, but the deep and extremely intense westerly momentum across West Texas did not allow the moisture to remain back west over the far western counties of western Oklahoma.  South-southwest winds at the surface were shunting the 50s dewpoints a county or so farther east, and the corridor of southeast winds were not really materializing in the Gage/Laverne areas.  I was expecting (and hoping) the initial towers to develop near Lipscomb, TX and then move across the Laverne area and eventually Buffalo, OK and points northeast from there.  What ended up happening was towering cumulus development occurring farther south and a bit east in the well-mixed air.  The initial group of tower cumulus developed from Arnett to Cheyenne, basically at the longitude I was already at.  I needed to adjust east.  So I did just that, and when I reached Buffalo there was an elongated cluster of poorly organized bases to my south-southwest.  I continued east to near Camp Houston and watched that area develop a little bit more, and radar indicated taller growth into the mid-levels.  I was basically right along the front, but the winds just north of the front were becoming southeasterly up to the KS border.  I liked this.  I thought that if this storm could form rapidly, it may just take advantage of this mesoscale sweet spot from northern Woods County into southern Barber County, KS.  I took a gamble with this first development, seeing as the second area of cumulus growth and echo on radar was quite a ways to the south still.  (this southern storm near Vici, OK ultimately developed into the long-lived supercell and “storm of the day”).  I figured, “bird in hand”, so I’ll play with this thing closer to me and already an established storm.

I went north on N2230 Rd a few miles east of Camp Houston and followed it north into Kansas.  Of course, by the time I reached the storm near the KS border, it was beginning to fall apart.  It still maintained some structure as it neared Aetna, but it was just so small.  I then opted to go east on Hackberry road (instead of continuing north on Aetna Rd. to Hwy 160).  The storm continued to move quickly northeast at around 40 mph or so, and as this was going on, the storm to the south, about 60 miles south-southeast of me was beginning to ramp up quite a bit.  I continued to observe updraft pulses with the storm just north of me, but the contrast was poor.  I came across some roaming bison on this open range that Hackberry Road meanders through.  That was pretty cool.  I was out of position with the southern storm farther away, and on a day like this when storms were moving 40-55mph, early decisions you make in the chase will largely impact what follows because there is no room for error.  I committed too soon on this chase on a storm that was too far northwest with respect to the warm/moist sector.  The storm to the south-southeast of me had much more real-estate of CAPE to work with, but the storm was fighting all this intense westerly component low level flow.  That kind of bothered me and was one reason why I second guessed the storm.  The southern storm ultimately became a very nice looking supercell on radar and an eventual tornado producer that a number of storm chasers saw.  Of course, the way I chase, I seek “the road less traveled”, and again it bit me.  Nevertheless, it was great to get out and dust off the cob webs (including my forecasting skills!) and kick off the 2011 storm chasing season.  Photos from the chase below:

« Newer PostsOlder Posts »

Powered by WordPress