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 30, 2006

High Plains Winter Storm Dec 29-30 [post 9]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 12:01 pm

Southwest Kansas Crippled!  This will be a storm folks in Southwest Kansas will be talking about for some time to come.  The warm conveyer "trowal" feed to the north of the dry intrusion is squarely over Southwest Kansas today… and is only budging slightly north with time.  Another big band of freezing rain is about to move through Dodge City which would surely add another 1/4 to maybe 1/2" on top of the 3/4-1" Meanwhile, freezing rain and sleet has changed to snow farther west now in the Liberal and Garden City areas as the warm layer aloft erodes away. 


December 1984.  For Dodge City, I think many will be comparing this current ice storm to that one, where major accumulations of over 1 to 1.5" of ice caused significant damage.  I drove through some of the older neighborhoods just north of downtown Dodge… and 9 to 20" diameter parts of trees are coming down left and right.  The popping sound is pretty amazing and streets are rapidly becoming impassable with so much tree damage in town.

High Plains Winter Storm Dec 29-30 [post 8]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 10:40 am

Just a mess in Southwest Kansas.   It is still raining moderately at 10:30am.  We have a significant accumulation of ice particularly on exposed objects.  The main roads are still just wet though… however, I drove about 25 miles west of here to Cimarron, and it is quite a bit worse there.  At least 1" of ice accumulation on everything… and the untreated roads are ice-covered out there.  I couldn’t tell what the temperature was there exactly, because my Jeep thermometer was reading 32° the whole time… and I know it’s 29 or 30° there in Gray County given the development of ice on the roads.  With the winds averaging 25-35 mph, areas like Liberal, Garden City, and Wakeeney must be approaching a disaster zone now as it’s still primarily freezing rain… and there’s so much more precip to go, too!  Here is one photo I took near Cimarron before I drove back to Dodge:

High Plains Winter Storm Dec 29-30 [post 7]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 7:34 am

ICE ICE and WIND!!  I just woke up at 7am after about 4.5 hours of sleep… to find a significant amount of ice accumulation on everything here on the north side of Dodge City.  Temperature is around 30°F and still dropping… with a long stream of moisture moving to the west-northwest per radar.  We are aboutt to get into some moderate precipitation… most likely freezing rain… and with a driving north wind of 25 to 40 mph… we may see some huge problems as we head deeper into the morning here in Dodge.  West of here, I can only imagine the mess… everything must be at a stand-still by now with huge amounts of ice accumulation and sleet.  Everywhere west of Dodge City-Meade-Hays where it rained 2.5" or more… has now just about completely frozen!  Yikes!   We will remain in this narrow stream of precipitation for quite awhile it looks like as it essentially "trains" over the area.

High Plains Winter Storm Dec 29-30 [post 6]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 12:28 am

Major problems west of Liberal-Garden City-Dighton in SW KS.   I got home around 11pm or so just as we were dropping to 32°F here in Dodge City.  The rain is now beginning to freeze on exposed tree limbs, metal objects, and much of my Jeep.  The temperature will continue to drop to around 29 or 30 by sunrise… and if it keeps raining for much of the night… we will have some major icing problems even here in Dodge City.  I think the rain, however, will be more widely scattered than it was during the day Friday, so I doubt we will see serious ice accumulations.  That could change though.  Boy, out west though… wow.  The snow line made it as far east as an Elkhart to Johnson to Scott City line by Friday evening.  During the afternoon… a couple spotter reports indicated 6 to 8" of snow with some significant drifting  about 5 miles or less from the Colorado border.  East of there.. the reports were far less with little accumulation of snow… as the primary precip type was freezing rain or sleet.  By evening…another huge burst of precipitation developed and moved northwestward into the cold air.  As temperatures plummetted to 28°F in the Dighton and Scott City areas… the 2.5" or more worth of rain that fell previously had begun to froze…with heavy sleet and snow developing in those areas.  As I type now… significant snow/sleet/freezing rain is falling west of Meade-Dodge City-Hays line.  In northwestern Kansas… well what can I say… they are true winners for this storm with regards to snow and wind… that and southeastern Colorado.  Numerous 12-15" reports with 6-8 foot drifts on 30-50 mph north winds.  Wow! 

December 29, 2006

High Plains Winter Storm Dec 29-30 [post 5]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 11:36 am

Front finally moved through.   It’s mid morning now on Friday and the front moved through here not too long after 9:00 am.  Temperatures are falling fast here in Dodge City now on north winds 15-20 mph.  The 32°F line is working its way southeast slowly…however, colder air continues to build in northeastern Colorado with lower 20s now in the northeastern Colorado high plains.  Winds will pick up significantly through the day in far western KS, driving the 30°F isotherm deeper into Southwest Kansas… and it looks like a very messy night west of a line from Scott City to Garden City to Liberal.  Below is the 10:00 am surface map:

 Bright Band.   As the heavy precipitation moved into northwestern Kansas this morning, a pronounced "bright-band" of 50-60 dBZ appeared east of Goodland.  This is caused when snowflakes are falling through a layer of the atmosphere that is at or just barely above freezing…where large snowflakes are trying to melt, but not completely.  Heavy sleet also usually appears as a "bright band" on radar. 

Lightning strikes!  The time is 11:30am, and we are getting an old-fashioned thunderstorm now in Dodge City with a temperature of 37°F.  The snow and winter >>  so close, yet so far away……….

High Plains Winter Storm Dec 29-30 [post 4]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 1:49 am

More ice now??  The warm layer aloft has now reared its ugly head in the GFS and NAM models.  Originally, it appeared that the 800-750mb warm layer would not be significant enough to cause problems with respect to mixed phase precipitation, but there’s no denying the big warm layer shown in the NAM and GFS model soundings for late Friday into Saturday.  There could now be a significant ice storm for portions of Southwest Kansas immediately east of the heavy snow area.  The "cold wedge" in the low levels is beginning to develop and overwhelm western Kansas.  There are a bunch of surface obs around 33 to 35°F from Elkhart to Hugoton-Ulysses to Johnson in far southwest Kansas.  It is 36F now in Garden City at 1am early Friday morning on a north-northeast wind.  This shallow cold wedge usually throws a big wrench in things because models have a difficult time handling this common aspect of high plains weather.  The 32F line is slowly working its way southeast…and will continue to overtake Southwest Kansas during the day Friday…with rain becoming freezing rain.  In fact, the NAM and GFS show indications of freezing rain here in Dodge City as early as Friday evening….with still an abundant of precipitation yet to go through.  It still appears as if widespread 2-3" storm total liquid equivalent precipitation will be realized over a good chunk of the region. 

As far as the snow situation goes… it looks like the majority of the precipitation will be snow over far Southwest Kansas after midday today mainly west of Ulysses-Hugoton-Lakin.  However, given the magnitude of the warm layer aloft, they even may not change over to all snow until early evening.  By this evening, very strong winds north winds will develop with gusts in the 40-50mph range in this area where the snow will most likely fall.  I think 8-12" will be common west of Ulysses-Hugoton-Lakin with blizzard conditions prevailing overnight tonight into Saturday.  

It’s 48F here in Dodge City, but the slooooowly moving front is going to be pushing through over the next couple hours it appears.  Below is the 1am CST 12/29 surface map over Southwest Kansas

December 28, 2006

High Plains Winter Storm Dec 29-30 [post 3]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 1:17 pm

A snowier scenario for Southwest Kansas!  Well, all the models seem to be in a reasonable agreement now through 48 hours (Saturday morning 12/30) in taking the mid level vorticity max through West Texas to a position near Childress, TX.  Surface response will be impressive with a compact surface low over Oklahoma somewhere.  Where in Oklahoma the surface low tracks… will play a huge impact in where the rain/snow line sets up for the "main show" when this mid level low/vort max impinges on Southwest Kansas.  Boy it is going to be close here in Dodge City… if the track is just a 30 miles more southeast…then the cold wedge can filter farther east… and Dodge City will see significant snow and wind on Saturday.  Right now, it appears snow and wind (with perhaps blizzard conditions at times), could be a very big problem west of a Liberal-Garden City-Dighton, KS line.  Below is a 6-panel of 500mb and Sea Level Pressure from the GFS, NAM, and Canadian models from this morning’s run:

High Plains Winter Storm Dec 29-30 [post 2]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 1:29 am

Farther South?  Well, the 00z/28 model runs I think are finally beginning to catch on to the magnitude of the digging jet down the backside of this trough along the Pacific coast.  When I was at work earlier Wednesday evening, I interrogated the GFS, NAM, and UKMET models against the RAOBs along the coast… especially Medford, OR and Oakland, CA… and all the models in the 6-12 hour forecast grossly underforecast the middle tropospheric jet streak by as much as 35 knots.  At 550mb, the Medford, OR sounding had around 120kts before the wind data was lost because of limiting angles (wind speeds too strong).  The NAM and the GFS both had about 75 to 80 knots at 550mb at Medford.  Well, the 00z initialization was closer on the GFS model, with 105kt analyzed.  The result?  A more digging system.  The storm will continue to dig well into northern Old Mexico/Southern New Mexico before carving out a significant upper low over West Texas.  See the comparison in the 12z/27 and 00z/28 GFS model runs valid for 6pm Friday:

Model QPF amounts are staggering on the 00z/28 runs!  The GFS below:

GFS model 60-hour QPF through Noon Sunday 12/31.  Interpolating for Dodge City suggests a little over 3"!

Even the Canadian model QPF amounts are very impressive… and this model is usually a little less aggressive with significant QPF amounts, based on experience:

12hr ending 6am Fri ~ 16mm
…ending 6pm Fri ~ 11mm
…ending 6am Sat ~ 18mm
…ending 6pm Sat ~ 24mm
…ending 6am Sun ~ 4mm
equals storm total ~
73mm or 2.87"!!   for Dodge City

It is looking more and more like a historic December precipitation event for much of Southwest Kansas with widespread 2-3" precipitation…including a major snowstorm for parts of far Southwest Kansas…mainly west of Garden City and Scott City.  Future model runs should help iron out the median rain/snow line for this event… but as it stands now… it appears to be largely a major cold rain event here in Dodge City still.

December 27, 2006

High Plains Winter Storm Dec 29-30 [post 1]

Filed under: Dec 29-30, 2006,General Weather & Forecasting — Mike U @ 12:24 pm

Here’s the first blog post of this event.  I’ll try to keep this blog fresh about twice a day (or more) until the event ends.  Another major winter storm is approaching the central High Plains… and it looks eerily similar to the December 19-20th storm… the only difference for Southwest Kansas is the fact that there will not be a pre-existing source of remnant cold canadian air (for freezing rain).   Below is the 60-hour total QPF from this morning’s 12z GFS run… pretty amazing:

Star = Dodge City, open circle = Denver, yellow dotted line = forecast mean position of rain-snow line through event

The problem for here in Dodge City is simple–  it will just be too warm for all snow.   The next problem is the fact that this system may evolve very similarly to last week’s storm… in that it will begin to slow down and occlude to the west southwest or southwest of Dodge City.  For large-scale cyclones like this… it usually means one nice shot of precipitation in the warm sector (the warm conveyer air stream), then the dry intrusion really takes over and the event is essentially done with…until the wrap-around air stream comes through…but by that time, the storm will be severely occluded and the best forcing for lift and precipitation will be over with… so only light accumulation of snow would occur, if that. 

Below is the GFS +48 and +72hr forecast from this morning’s 12z (6am) run:

blue arrow = warm conveyer air stream where significant precipitation occurs (where you want to be!)
yellow arrow = dry intrusion (where you don’t want to be!)   …if you like precipitation
thin arrow points to Dodge City, KS in the 700mb panels
green dotted line in the 850mb panels denote approximate rain-snow line

The 700 and 850mb do not change much in 24 hours.  The locations that remain in the vicinity of the blue arrow (in the moist conveyer) for 24 hours or more will see some major precipitation…and on the cold side of the dotted rain-snow line… well… you can put two and two together.  It looks like another 18"+ event for someone on the Colorado Front Range and/or High Plains.  More later…

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