I saw close to moderate snow today…

And some people living on the north side of Lake Overholser in western OKC may have seen quite a bit of snow.

Actually… I was sitting at Memorial and MacArthur in far northwest OKC when we had a period of light to moderate snow.  I had not been paying attention to the weather and just assumed that we were getting enough lifting from some synoptic mechanism to cause the snow.  When I got home and was able to look at radar… I realized that we were dealing with a VERY localized event.  One that I have seen snow from a few times in the past… but never seen on radar before.

I thought I had the scoop… but the National Weather Service in Norman was quick to see it unfolding and put up a graphic explaining the event on their webpage.

They focused on the power plant in western OKC… but we were seeing snow from a different source.  I believe that the snow I saw was coming from a water treatment plant located on the north side of Lake Hefner.

There were probably several other places in central Oklahoma that were seeing snow from “non-weather” sources… just another fun item associated with this winter event.

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It’s Been Over 7 Years…

 

The second severe winter storm of the season hit Oklahoma on January 28th and 29th.  In many ways this system was more damaging than the blizzard which struck Christmas Eve.  As much as ten inches of snow fell in the Enid area… and an ice storm affected the southwest quadrant of the state resulting in over 150,000 people being without power at one time.  It looks as if ten’s of thousands of people will be without power for many days to come. 

For Oklahoma City… there was ice to deal with on day one of the event and as much as six inches of snow on days two.  In Okarche… the storm total of 5.7 inches included 1.1 inches of sleet on the 28th and 4.6 inches of snow on the 29th.  The 4.6 inches of snow was last topped in a single day on November 30, 2006 when 4.8 inches of snow fell.  The storm total of 5.7 inches was last topped all the way back on December 23 and 24, 2002 when 9.6 inches of snow fell. 111 [800x600]

That was fun… now it can go away please…

 

Snowcast Event 6 – Update 7 – Noon, Fri, Jan 29

Latest water vapor imagery shows strong vort center moving east into northwest Texas.  RUC shows this feature tracking east and then east northeast during the next 12 hours toward east central Oklahoma.  This seems a reasonable scenario and we may finally have a handle on this system – just as it comes to an end.

Strong lifting north and northeast of the vort center is expanding/organizing and increasing the intensity of precipitation across Oklahoma.  SPC meso-analysis shows that critical thickness values have FINALLY lowered sufficiently for all snow northwest of a line from Waurika to Purcell to Chandler to Miami.  This line will continue to advance east through the afternoon.  It appears that the center of the strongest lifting/wrap-around duration will extend from Cordell to Oklahoma City to Jay.  In this area… an additional 1 to 3 inches of snow is likely… 4 to 5 would not be out of the question… especially from just west of the OKC metro area to the Arkansas border.

Radar returns in precipitation southeast of the snow area continue to suggest sleet… and there is likely a band of freezing rain across portions of southeast Oklahoma.  For now… about the 8 southeastern most counties of Oklahoma continue above freezing… but should be able to switch to a winter mix before the event comes to an end this evening.

At the current time in Okarche… moderate snow and flowing electrical power.  It’s a beautiful day…

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Snowcast Event 6 – Update 6 – Midnight, Fri, Jan 29

The forecast remains very complex even at this stage.  A solid base of ice, sleet or snow has been put down across almost all of Oklahoma with the exception of the southeast.  Additional freezing or frozen precipitation will have no problems accumulating.

Some moderate to heavy rainfall is occurring in the southeast… but most of it is southeast of the surface freezing line.  In fact, some temperatures near 40 degrees reside along the Red River.  A very slow southeast advance of the freezing temperatures will result in some freezing rain evolving during the next 24 hours… some of the ice accumulation may be significant.

Most snowfall has ended in the Panhandle and far northwest… however, indications of increased lift are showing up from central Oklahoma northward.  More than a couple of inches of snow will be possible the remainder of the night in north central and northeast Oklahoma.  Central sections will see a mix of light freezing rain, sleet and snow.  Accumulations in central Oklahoma should generally be light / less than an inch / but may serve to amplify problems that already exist.

Models are in general agreement that strong vort center over New Mexico/west Texas will move east-northeast during the next 18 hours very close to the Red River.  This will result in additional precipitation forming in Texas and spreading northeast through much of eastern Oklahoma.  Latest SREF and NAM signal accumulating snowfall farther west than the GFS.  NAM solution brings snowfall as far west as Lawton and Kingfisher… while GFS keeps main show to the east of I-35.  All models are similar on precipitation amounts and type with snow being the primary mode.  With the existing snow/ice pack… accumulations on the order of 1 to 4 inches should be easily attainable.

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Snowcast Event 6 – Update 5a – 9:05 p.m., Thu, Jan 28

Details about the winter weather event of today are just starting to roll in.  A guess of near 100,000 customers are without power at this hour in parts of southern and western Oklahoma.

Light to moderate snow will continue across the northern part of the state and the Panhandle for the next several hours.  A band of snow/sleet has formed in southwest Oklahoma and is pushing in on the OKC metro area.  It appears that there will be more snow through the day on Friday… especially across the southeastern half of the state that I will address later.

In Okarche… as the main event ended… we had a melt down of 0.92 inch.  1.0 inch fell as sleet.  There has been a trace of snow since…

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Snowcast Event 6 – Update 5 – Noon, Thu, Jan 28

Complex upper trough of low pressure is moving out of the southern Rockies and northern Mexico into the southern Plains this morning.  Strong lifting associated with lead vort max is producing widespread precipitation – which ranges from snow in the northern Texas Panhandle to freezing rain over much of central and western Oklahoma to severe thunderstorms in southwest Texas.

Trailing vort max is evident in water vapor loops spinning over southeast Arizona.  The morning NAM takes the lead max slowly north and northwestward back into New Mexico and begins moving the Arizona max southeastward under it toward southwest Texas by Midnight tonight.  Afterward… the combined vort max starts its move eastward toward the Red River Valley by sunset on Friday.  Widespread precipitation – with occasional breaks – will continue until the system clears the area during the overnight hours from Friday into Saturday.

15Z special sounding from Norman continues to show a profile favorable for freezing rain.  However… temperatures around 850 MB have cooled slightly since the 12Z release.  There is still a considerable way to go before the profile would be more of a sleet and snow producer… meaning that the zone of freezing rain should continue for the next several hours.  Another special sounding should be made available soon.

The freezing line advanced farther south than expected over southwest and south central Oklahoma… but not quite as far as expected over eastern Oklahoma.  Using the current position – along with mesonet observations which show frozen anemometers – it has become apparent where the most significant icing is going to continue to occur.

There has been off and on sleet with the precipitation in Okarche this morning… and snow developing in the Texas Panhandle should soon be spreading into the northwest part of the state.

Tweaking graphic to account mostly for current trends… will continue to investigate the recent NAM signal for band of heavy snow Friday night in central and eastern Oklahoma.

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Snowcast Event 6 – Update 4a – 8:42 a.m., Thu, Jan 28

…Severe winter storm event unfolding in Oklahoma…

1. Freezing line has advanced southward quicker than previously expected and is well south of OKC at this hour.  OG&E is not reporting any system outages at this time… but mesonet data is showing that anemometers have frozen up from near and just west of OKC through west central and southwest Oklahoma.  So… trees and power lines are also likely loading up.

2. Morning NAM is now suggesting that a trailing vort center may produce some heavy snow in portions of central and eastern Oklahoma overnight Friday into Saturday morning.  Will need to see how this compares to other model data and consider adding accumulations to the total event on the next update…

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Snowcast Event 6 – Update 4 – Midnight, Thu, Jan 28

Hide and watch… that’s about the only thing to do now.  A significant winter storm will be unfolding across the state within the next 18 to 24 hours.  MANY questions exist with regard to timing of precipitation transitions from rain to freezing rain to sleet to snow -also with regard to total accumulation amounts.

Cold enough air through a deep enough layer should settle into the Panhandle… northwest and part of north central/northeast Oklahoma for the precipitation to come in the form of snow.  There will be significant amounts… especially in the Woodward and Alva area where isolated amounts could push 18 inches.

The sub-freezing surface air will have a hard time pushing into southeast Oklahoma… and generally light accumulations of freezing rain, sleet and eventually snow are expected.

With the two above mentioned regions lay the highest confidence of the forecast.

This leaves a broad zone from southwest to central to east central Oklahoma with the greatest concentration of possible precipitation zones – and thus, the lowest confidence of the forecast.

This update focused on fine-tuning these zones.  The most significant changes were shrinking the range of the zones in question as well as shifting the eastern end southward – and the western end northward.  This move didn’t change the look of the forecast all that much in central Oklahoma.

The freezing line has pushed into the Panhandle and far northwest Oklahoma at this hour and will continue to shift toward central Oklahoma by daybreak.  Thereafter… it is expected to only make slow progress southeastward during the day.  It is likely to hang up from somewhere west of Ardmore to near Ada to near Fort Smith by late afternoon.

Ice storm conditions – where trees and power lines collapse – usually occur in narrow zones with systems of this nature… possibly on the order of only 20 miles or so wide.  It is nearly impossible to predict where a zone that narrow will fall until the event begins unfolding.  For now… it appears that the most likely area will extend from near Altus and Snyder in southwest Oklahoma – to the OKC metro area – toward southern Tulsa.  Mostly freezing rain and some sleet will fall south of this area… while accumulations of sleet and to a lesser extent, freezing rain will be found to the north.  These areas will also see at least some light accumulation of snow on top of the ice and sleet before the precipitation ends Friday morning in the southwest and early Friday evening in the east.

An attempt will be made to further refine the forecast at Noon… however, as previously mentioned… it is likely that the event will need to start unfolding before high impact areas can be recognized.  Preparations for the storm should be completed.  Much of the northwest 2/3’s of Oklahoma will see deteriorating weather conditions as the day progresses.  By overnight Thursday into Friday… it is very possible that large amounts of the power grid could be damaged or shut down… along with the usual travel issues that come from winter storms.

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