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!"

January 28, 2010

2010 Jan 28 winter storm photo

Filed under: 2010 Jan 28 — Mike U @ 9:39 am

I took this shot from inside my hotel room in the south part of Dumas, TX looking out toward Highway 287.  Time of image 8:30am CST:

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Southern Plains Winter Storm 2010 Jan 28 [post 11]

Filed under: 2010 Jan 28 — Mike U @ 8:36 am

Winter precipitation underway! The precipitation began as sleet in Dumas at about 6:45am or so.  There were a few flakes mixed in through about 7:15 or so, and by 7:30am more flakes were mixed in and it was about half sleet/half snow.  By 8 or 8:30am, it should be all snow here, with heavy snow most of the day and northeast winds 15 to 25 mph with higher gusts in the 30-40mph range this afternoon!

Southern Plains Winter Storm 2010 Jan 28 [post 10]

Filed under: 2010 Jan 28 — Mike U @ 6:45 am

The fun begins at about 7:30am! This radar image is nuts.  A lot of the yellow and orange (40 to 45 dbz) returns are due to snow falling into the warm layer.  Water-coated snowflakes are highly reflective.  This is called “bright banding”… and there is vertical continunity to the 40-45dbz band as you go up in elevation angle.  This huge, heavy precipitation area is moving north at about 35 mph, and the leading edge will reach Dumas at around 7:30 or so.

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Southern Plains Winter Storm 2010 Jan 28 [post 9]

Filed under: 2010 Jan 28 — Mike U @ 4:38 am

Sleet showers moving through right now at 29 degrees… but look what’s coming! Well, I managed a little under 3 hours of sleep, LOL.  After this blog post, I’ll try to catch about 3 more before the snow starts.  I haven’t talked too much about the wind component of this storm, but there will be at least enough to cause moderate blowing and drifting this afternoon.  The surface low will be too displaced to the southeast and the Canadian surface ridge axis will also be a little too close to the northern Panhandles for major wind, but during the height of the storm this afternoon, with the heaviest precipitation rates, the winds will be at their strongest.  850mb winds off the NAM12 model will peak at about 21z around 30 knots or so over Dumas, so it’s conceivable we will see frequent 30 knot gusts here for at least 2 or 3 hours this afternoon.  This gets pretty close to blizzard criteria, and since this will be happening during the highest snowfall rates, I expect visibility to fall below 1/4 of a mile rather frequently between around 2pm and 5pm.  12-15″ storm total snow still looks to be on target for Dumas, so long as we are not sleeting anytime after 7am, because that will then start the clock on limiting snowfall amounts… and based on all the model guidance of the warm layer aloft, I don’t see that happening for here in Dumas.  We’ll see how good the models are.

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Southern Plains Winter Storm 2010 Jan 28 [post 8]

Filed under: 2010 Jan 28 — Mike U @ 1:20 am

The Warm Layer Aloft. Below is a chart from the 00z NAM12 of 800mb Temperature and Wind valid 12z, 15z, 18z, and 21z tomorrow.  800mb is about the level where the warm layer aloft (WLA) maximum temperature is occurring.  As a general rule Snow is favored where WLA < +0.5C.  Sleet is favored warmer than this up to about +3C.  Freezing rain is favored generally where WLA maximum temperature is greater than +3C.

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January 27, 2010

Southern Plains Winter Storm 2010 Jan 28 [post 7]

Filed under: 2010 Jan 28 — Mike U @ 6:21 pm

Arrived in Dumas this afternoon. I have arrived at my two-day temporary stay of residence here in Dumas.  Coming into town, the temperature was 61 degrees, but the leading edge of the storm was starting to become evident as high, dense cirrus was quickly moving in.  The forecast still appears to be on track.  I think the snow will start in earnest sometime between 6 and 8am.  Before then, there will probably be off and on light sleet/snow mixture for a couple hours before sunrise perhaps.  Below is a two-panel chart of 48-hr snowfall accumulation from the 12z Hi-res NMM WRF and the 18z NAM model.  The yellow star denotes where I am at (Dumas, TX).  This is a snowfall accumulation algorithm using the Kuchera method.  The grey bullseye area around Dumas is 18″ according to this algorithm from these two models and red is 15″+

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Here is a water vapor satellite image showing the storm.  The primary low is at the base of the trough over the far northern Gulf of California.  It will progress eastward this evening before rounding the corner and heading northeast into SW TX as the upstream “kicker” potential vorticity (PV) anomalies continue to move south to the base of the trough:

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Southern Plains Winter Storm 2010 Jan 28 [post 6]

Filed under: 2010 Jan 28 — Mike U @ 11:52 am

Departure for Dumas! Well, the latest 12z GFS and NAM have definitely trended toward the ECMWF and UKMET models.  The 12z GFS shows liquid equivalent precipitation around 1.25″ for Dumas and the NAM shows about 1.75″.  I think a solid 12″ snowfall is looking pretty darn good, with much of it falling during daylight hours tomorrow!  I have just made hotel reservations in Dumas and will be departing Dodge City by Noon.  Next update will be from Dumas.

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Southern Plains Winter Storm 2010 Jan 28 [post 5]

Filed under: 2010 Jan 28 — Mike U @ 5:38 am

Shifting my thinking back northwest into the TX Panhandle in favor of the ECMWF and UKMET models. A lot of folks (mainly non-meteorologist winter weather enthusiasts and storm chasers) love to look at the NAM model in the 36 hr+ time frame with winter storms.  That is fine and all, but when there is disagreement between the NAM and the more reliable global spectral models (GSM >> UKMET, ECMWF, GFS, Canadian GEM), the GSM prevails.  The UKMET and the ECMWF are nearly identical with a slower solution and taking the mid level potential vorticity (PV) anomaly northeast through West Texas. ..the nose of which into the TX Panhandle Thursday/Thursday evening (28th).  The 700mb low will track across the southern TX Panhandle, and will be most mature as it exits eastern NM and enters the southern TX Panhandle Thursday and Thursday night.  The 700mb RH and Wind fields off these models are rather different vs. the NAM.  The NAM appears to be veering winds out too quickly and I think the convective parameterization scheme is causing some upscale growth havoc which is limiting precipitation across much of the TX Panhandle (storm total QPF of 0.6 to 0.8″ instead of 1.2 to 1.4″)  I’m still worried about the stubborn warm layer aloft, too.  Last post’s idea of going to I-40 at either Erick or Elk City is looking less favorable now after assessing the GSM solutions instead of blindly looking at the NAM.   I can still look at the 12z model runs before making a commitment on a target city, but I am becoming more convinced that the Northern TX Panhandle is the place to be regarding heavy snow (12 to 15″).  I predict that the NAM model will begin to trend toward the GSM solutions (mainly the UKMET and ECMWF compromise) in the 12z run or perhaps as late as the 00z run late tonight.  I am now thinking as far west as Dumas, TX to document this storm.

January 26, 2010

Southern Plains Winter Storm 2010 Jan 28 [post 4]

Filed under: 2010 Jan 28 — Mike U @ 6:20 pm

More snow now instead of sleet a bit farther southeast?! That is what the latest trend is in the NAM and GFS models.  Yesterday’s model runs had a bit more impressive warm layer aloft, but this morning’s runs are colder farther southeast in the critical warm layer aloft (centered at 800mb).  Any sleet will likely rapidly change to snow mid-late morning now as far southeast as Erick to Clinton, OK.  If this trend holds, and these locations see more P-Type = SN, then MAJOR LEAGUE accumulations are likely in excess of 12″ over a fairly large area… and even upwards of 18 to 20″ in sweet spot!  I firmly believe that there will be at least a 3-6 hr period of blizzard conditions as well.  Model 10-meter winds are typically too light in these situations.  Just look back at the Christmas Eve Oklahoma Blizzard.  No one really expected blizzard conditions in Oklahoma City 24 hours prior to the event.  My early evening thinking now, the day before departure, is now reserving two-night stay (maybe even a third night, Friday Night, if worse case scenario pans out) at a hotel along I-40 in west-central Oklahoma.  I managed to get a shift swap at work, so I am not due back to Dodge City until afternoon/evening Saturday.  Check out these ridiculous QPF forecasts from the Canadian model and GFS model:

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Southern Plains Winter Storm 2010 Jan 28 [post 3]

Filed under: 2010 Jan 28 — Mike U @ 10:23 am

Stay away from the sleet! The goal of this snow/blizzard trip is to stay away from mixed-phase precipitation as much as possible.  It’s inevitable that there will be at least a little bit of freezing rain/sleet at the onset of the storm, but a prolonged period of this mixed precipitation only cuts down on snow totals, so in that regard, I must hedge north.  At the same time, I want to get into the good wind aspect of this storm, which will probably be a bit farther southeast… however the MSLP field during the height of the storm is a bit deceiving, because farther northwest where the MSLP gradient is forecast to be just a bit more relaxed closer to the arctic ridge axis… there will still be a strong gradient and 30-45 kt winds in the 900-800mb layer, therefore during heavy precipitation, these will mix to the surface in frequent gusts.  Right now, based on what I was looking at last night from the ECMWF, UKMET, Canadian models… and taking into account the stubborn mixed precipitation phase of the storm… am thinking of any of these three towns/cities to experience this storm from late Wednesday through Friday:

  • Pampa, TX
  • Canadian, TX
  • Woodward, OK

Unfortunately, it looks like the heart of this storm will occur during the 00-12z Friday time frame… at night.  Nevertheless, at daybreak Friday, it could be quite a scene at all three of these above locations.  Here is the impressive 60-hour QPF from the latest 12z NAM model:

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