Snowcast Event 3 – Update 3 – Midnight, Wed, Dec 31

Hate to break continuity by returning snowfall to the forecast for Thursday… however, there is mounting evidence that there may be a quick burst of snowfall in the southwest part of the state – starting as early as daybreak in the Panhandle and spreading southeast from there.  It should clear the Red River area by evening.

Satellite presentation of shortwave/vort max spinning and dropping southeast toward the Four Corners is fairly impressive this evening.  Most model solutions are now squeezing out enough QPF to suggest accumulating snowfall in the southwest part of the state today.  Moisture should be somewhat limited and the system should be moving quick enough to limit amounts to less than three inches in the heaviest areas.  It is worth noting however – new NAM is forecasting five to six inch totals near I-40 in western Oklahoma and a couple of inches toward the metro area.  The system appears to be moving too quick to allow such amounts… but a couple of inches seem reasonable.

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Snowcast Event 3 – Update 1 – Noon, Tue, Dec 29

Enough evidence is starting to come in to suggest that there will be another minor snow event in the state on Thursday the 31st.  This one will be lacking moisture the previous couple have had as it slides east southeastward out of the central Rockies.  The main impacts will stay well southwest of the OKC metro area.

As it looks now… light snow should begin in the Panhandle and along the southwest and south central part of the state by daylight Thursday.  There is some question to the depth of the cool air… but for now, we will lean to the side of snow or a snow/rain mix.

Amounts should be light with little more than an inch of snow in the heavier areas.

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Snowcast Event 2 – Update 4 – Noon, Tue, Dec 29

Still not a whole lot of reason to change much with this minimal storm.  Mid level radar echos are spreading north of the Red River at this time… and we should wet bulb down with snow starting during the next few hours.  There have been some areas on 12z model data that suggest some locally heavier amounts… but feel that they will still all fall in the 1 to 3 inch range that is currently going.

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Snowcast Event 2 – Update 2 – Noon, Mon, Dec 28

Timing of system approaching tomorrow is similar across the model suite and with fairly high confidence – it appears that snow will spread into southwest Oklahoma around noon….ending in the central part of the state just after sunset and exiting the northeast corner around daybreak on Wednesday.  Not a very strong system… but should be capable of producing 0.10 to 0.25 of an inch of precipitation – making this a one to three inch snow event across a large area.  Changes in this forecast include spreading the “heavier” snow northwestward into the panhandle to account for a slightly more northwest track of the vort max – and – reducing some snow amount/area in parts of the south central and southeast where enough above freezing air in close proximity may reduce amounts slightly.  While this does not have the look of a major event… the ground is quite cold – in some cases snow covered – from the previous big event.  Snowfall tomorrow should be able to go straight to accumulating.  Also… with light winds / Oklahoma standards / there will be a better chance of snow covering roads instead of just drifting areas like the previous storm.  There may be more widespread problems with regard to roads having more area snow covered – even if drifting will be much less of a problem.

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Snowcast Event 2 – Update 1 – Midnight, Mon, Dec 28

00Z GFS/NAM are fairly similar in their solutions of southwest U.S. system moving into the southern Plains by Tuesday afternoon and evening (29th).  The GFS is slightly slower – and slightly stronger with the vort max forecast to be just west of Wichita Falls by sunset on Tuesday.  Am somewhat inclined to run with the GFS based on its handle of previous major storm.  Unlike previous storm… there should not be a strong warm sector feeding into this system – with advection coming from recycled air that has filtered south through the eastern U.S.  Forecast sounding support an all snow event across most of Oklahoma with the upcoming storm.  However, speed of system and limited moisture should keep overall amounts low.  At this time… it appears that a broad area of light snow will spread across the state… with slightly heavier amounts possible from the southwest to northeast / near and north / of vort max.

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Summary Event 1 – Blizzard of Christmas Eve

The “Blizzard of 2009” will be long remembered by people in Oklahoma.  The storm was one of the most intense on record with regard to its combination of snow, wind and low pressure.  There have been many other blizzards in the state that have had larger snowfall amounts… but the wind associated with this storm made it particularly noteworthy.  Also… the area of the state affected by the storm doesn’t typically see blizzards.  They are usually confined to the Panhandle and northwest part of Oklahoma.

 

The strength of this system was well forecast by models… which indicated a strong upper storm and surface cyclone would intensify and spread out into the Plains in the days leading up to Christmas.  This solution was evident in model data upward of a week in advance.  However… it appeared that it would take a more typical trip through the Panhandle and into the central Plains.  Travel would be a great concern for folks leaving Oklahoma to the north and west.

 

As the system approached… model guidance began to suggest a farther south track which would bring the most significant impacts into the main body of the state.  As time went by… those severe impacts looked like they would be getting closer and closer to central Oklahoma and the OKC metro area.  Also in the process of shifting the impact southeastward….data suggested that the storm would produce very significant amounts of snowfall and wicked amounts of wind as extreme surface low pressure became organized over the southeast part of the state.

 

24 hours before the event started…. it appeared that the stage was set and Oklahoma needed to brace for what could be a record setting event.  Anyone wishing for a White Christmas may want to watch what they wish for.  It was on its way and it meant business.

 

Initially, the storm was strong enough to drag warm air aloft back into the center part of the state which caused a large area of freezing rain and sleet to occur in the early hours of the event.  On average, about 1/3 of the melt down precipitation was in rain and sleet form.  Then the changeover occurred.  As enough cold air worked its way into the core of the system… snowfall began falling over a broad area from southeast to central to northeast Oklahoma and persisted for many hours.  This was made troublesome by the fact that it was impacting the largest population of the state during the final shopping day before Christmas.  Despite forecasts of a winter storm – one that was upgraded by the National Weather Service around Noon on Christmas Eve – to a Blizzard Warning – many people braved the roads.  This turned out to be a major mistake with travel being brought to a standstill in almost all areas.  Huge areas of interstates were shut down and rescue operations were set in motion to gather up stranded drivers.  It was a worst case scenario.  A few people even lost their lives.

 

Forecasting the system was difficult…. with a steady trend by data to shift the emphasis south.  While some people in the northwest had many days of warning… others in the eastern part of the state only saw 12 to 24 hours of notice that a major winter storm would be heading their way.  Also… it wasn’t until about 6 hours into the event that it became realized that portions of south central, central and northeast Oklahoma would see the amounts of snow that they did.

 

Then there was the wind.  The wind blew all day….gradually increasing from 35 and 40 mph to 50 to over 60 mph at many locations.  It reached a point where it was hard to stand up in and created drifts in the OKC metro area that had not been seen by many before.  It may very well be a long time before they are seen again.

 

With regard to the 14.1 inches of snowfall reported at Will Rogers Airport…. I am inclined to politely say, no.  I think this total was about five inches overdone.  I love seeing records being broken…. but not when they are incorrect.  My drives around the city during the days afterward have not shown me anything that indicates more than seven or eight inches of snow fell in most areas.  Then the meltdown of 0.94 came in from KOKC and I was sure that 14.1 inches of snow did not fall – probably more on the side of 6 to 8 inches at best when considered that 25% of the 0.94 came in the form of freezing rain and sleet at the beginning of the event.  It is a record that I would like the National Weather Service to examine a little further before setting in stone.

 

In Okarche… we stayed just west of the heaviest snow and recorded 2.9 inches.  Drifts of over two feet were common around town and at the peak of the storm it really looked like a blizzard.  White out conditions reduced visibilities to less than 100 feet at times.

Satellite picture after the event:

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Max wind gusts from the Oklahoma Mesonet – Will Rogers Airport also exceeded 60 mph…

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Max wind gusts:

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Snowfall from the Tulsa National Weather Service:

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Snowfall from the Norman National Weather Service:

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My “best guess snowfall amounts” and the snowcast showing the greatest amounts forecast for each county.  The eastern side was handled fairly well – however, with little advance warning.  The northwest and panhandle were an indication of the storm track farther south than expected in the early forecasts.  Overall… the heavy snow centers were forecast to have decent amounts of snow…. but probably not near what my forecast indicated:

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Snowcast Event 1 – Update 7 – Noon, Thu, Dec 24

Warm air nosing in a few thousand feet up – wrapping around very strong storm – has resulted in a painfully slow process of a switchover to all snow in the central parts of the state.  However… it appears that the change is in progress and shifting east.  Sustained winds near 35 mph with frequent gusts in the 53 to 63 mph range have been occurring which have reduced visibilities to near or less than 1/4 of a mile where all snow is falling.  That and the fact that this looks to be a several hour long event and we can call it a Christmas Eve Blizzard.

The only changes needed to be made to the snowcast is to add some more accumulations further east… and reduce accumulations in the Panhandle.  Morning NAM came in with still amazing total amounts near 15 inches in central Oklahoma.  This is probably more than double overdone as much of the time was given to sleet.  However…. broad areas of greater than four inches look possible from the southwest part of the state… northeast through the metro area and points northeast.  It might not rank up there with some historical blizzards… but it’s still going to be a storm to remember…

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