Major Winter Storm Still Expected…

As more model data continues to come in… it is evident that portions of Oklahoma will likely see severe winter storm conditions during the afternoon and evening of Thursday the 28th.  There remain questions with regard to the track of the storm – and resultant winter weather types/intensity – but the expected strength of the system at its arrival hasn’t changed.

A large upper trough should lift northeastward through the New England states by early Wednesday… with a deep area of low pressure dropping in behind it from Hudson Bay into the Great Lakes.  This will bring a surge of cold air southward through the upper Midwest and Plains… entering Kansas during the early part of the day.  At the same time… a strong upper storm system will be dropping southeastward along the California coast… toward northern Baja California.

By Noon on Thursday… it is expected that the cold front will have pushed through most all of Oklahoma.  It is also appearing that the surface air behind the front may be colder than previously expected.  The Baja system will be making a turn toward the northeast by then… ejecting toward the southern Plains.  Lifting associated with the front and approaching upper system will result in widespread precipitation developing from the high Plains of Colorado and New Mexico… eastward across Oklahoma and Texas.

This is where the forecast becomes tricky.  Surface low pressure will organize in central and eastern Texas.  As the surface pressure gradient strengthens between the low in Texas and the high over the upper Midwest… low level winds will increase across the state.  This will result in denser and colder, low level air pouring into Oklahoma.  Meanwhile… the low pressure in Texas will also result in an influx of slightly warmer air just above the surface wrapping back into the central and eastern part of the state. The result may be an area of significant freezing rain from portions of southwest Oklahoma… northeastward to areas near and southeast of Tulsa.

Further northwest… the air should be cold enough – through a deep enough layer – for the precipitation to fall in the form of snow.  And there will be a lot of it in a small zone.  Situations like this have resulted in snowfall on the order of 12 to 18 inches before.

The latest model trends have been to take this system slightly – slightly – further south.  This means that previously… where the heaviest snowfall was expected to be in northwest Oklahoma… now may occur from the southwest to central to northeast sections of the state.  However… without the system being onshore – and not being sampled properly by upper air networks – this southward trend may continue over the next couple of days.  Conversely… with more sampling… we could just as easy see the track being farther to the north.  Bottom line… it’s anybody’s guess at this point.

One thing seems certain… winter weather will be returning to the state… and for some, it will be in a big way.  I’ll be holding off on my snowcast until Tuesday at Noon… and no doubt… it will be including some big numbers…

Major Winter Storm Remains on Track…

At 72 hours in advance… it remains difficult to say just where the most serious winter weather will occur… but trends continue to point toward a large part of Oklahoma seeing some bad conditions develop during the day Thursday.

After a breezy day today… things will turn out quite mild on Tuesday and most of Wednesday before a cold front slips southward across the state Wednesday night.   By Thursday morning… widespread precipitation will break out across much of the southern Plains as lifting associated with a storm system approaches from the southwest.

There may be a small zone where freezing rain occurs – with the best guess from northwest Texas to central and east central Oklahoma.  But as the day progresses, a transition to snow is likely for about the northwest 2/3′s of the state.  The earliest change over to snow will take place in the northwest.  Some parts of Oklahoma stand to see a lot of snow.  Many model solutions over the past 24 hours suggest that the greatest snowfall will be about 75 to 100 miles wide and extend east/west along and north of I-40.

The storm will be a wet one… with the possibility of more than a couple of inches of melt down or liquid precipitation.  This means in areas where most of it falls as snow… there is a likelihood that as much as a foot of snow may fall.  It should be a heavy wet snow… but still capable of drifting given the 30 to 40 mph winds that will come along with it.

The National Weather Service in Norman has already pulled the trigger on a Winter Storm Watch for the entire county warning area starting Thursday morning.  This means that the word will be out to everyone by the 5 p.m. news.  I had hoped to have my food shopping done before the masses heard the news… I think I’ll head out this afternoon….

It’s far too early…

… to call Winter over yet.  January has been a very interesting month so far… and it appears that it has a chance to go out with a bang.  For as cold as it was to start off the month… temperatures have been above average for as many days as they have been below.  We still will probably end up with a below average temperature… despite having more days above average.  It’s hard to make up for the four days that were at least 20 degrees below average between the 2nd and the 9th.

Now on the horizon is a new winter storm that will affect the state on Thursday the 28th.  Model data over the past 24 hours has been similar in the strength of the storm – and pretty much in line with regard to the track of the storm.  The new GFS is actually fairly ominous… producing widespread heavy snow in the state 96 to 108 hours from now.  It’s far too early to tell exactly where the heaviest snow is likely to fall… but much of western and northern Oklahoma look to have the greatest chance.  The system looks like it will be able to tap into quite a bit of moisture… meaning significant snow – on the order of 6 to 10 inches – will be possible in the hardest hit areas.  Stay tuned….

Stop the clock!

We can stop the “no-thunder” count at 82 days… well short of a record.  Still, that’s a pretty good run with no boom-boom.  Thunder was last heard in Okarche on October 29, 2009 – associated with storms that produced 1.61 inches of rain.  The count came to an end on January 20th as heavy thunderstorms rolled out of southwest Oklahoma into the central sections of the state… bringing brief heavy rainfall and a lot of small hail.  By the way, small is smaller this year than it was last year.  The National Weather Service has raised the minimum severe hail size from ¾ of an inch to one inch this season.  We SHOULD see less severe hail reports… though I think we may just end up with quite a few more one inch hail reports.  Time will tell.  The hail that fell in Okarche on the 20th wouldn’t have met severe criteria this year or last.  It was only about ¼ inch and lasted about five minutes.  The quick 0.16 of an inch of rain was just enough to get water moving in the street and knock some dust off things.

I know you are asking – “what is the longest time without thunder in Okarche?”  A couple of periods exceeded 100 days:

121 NOV 1, 2005-MAR 2, 2006  
115 NOV 2, 1995-FEB 24, 1996

Long streaks like the one we just finished and the record streak listed above have to start near the end of October or first of November and then be followed by many months of typical winter weather.  You can bet we will be seeing thunder many times over the next 82 days.

Foggy, Frosty, Sunday Morning…

During the early morning hours of January 17th… the weather became interesting in Okarche with dense fog rolling in and out of the town several times.  There were times that the fog was minimal – only patchy ground fog with little reduction to visibility.  At other times… dense fog obscured the sky and limited visibility to less than ¼ of a mile.  Each time the fog became dense… my weather station would observe the change in temperature and dew point data.  It would become more moist and the “cloud on the ground” acted as a blanket to edge temperatures upward.  During an extended period of little fog… the temperature fell from 29 to 24 degrees between 3 and 5 a.m.  In quick time… the fog became dense again and the temperature came back up to over 29 degrees.  This would last until just before sunrise when the dense fog cleared out for good and the temperature fell back to the morning low of 24.  These weather changes were caught on the following graph here in Okarche:

http://www.okweatherwatch.com/2010/011710d.JPG

 

Just before sunrise… I drifted out to catch a few pictures of the remaining fog:

http://www.okweatherwatch.com/2010/011710aa.jpg

http://www.okweatherwatch.com/2010/011710bb.jpg

http://www.okweatherwatch.com/2010/011710cc.jpg

2009 in Review…

As with any year… 2009 was an interesting one in many ways.  Starting with temperature: 2009 was the coldest year I have recorded since beginning record keeping in 1993.  The average temperature of 58.3 degrees was just shy of the 58.4 degree previous record set in 1993.  It was 2.3 degrees below average (60.6).

There were 96 days where the temperature lowered to at least freezing… which was well above the average of 77.8.  Temperatures reached 90 degrees 73 times which was below the average of 80.5.  Interestingly, the temperature reached 100 degrees 20 times which was very close to the 20.7 average.

The total precipitation of 33.36 inches was 92 percent of the average 36.42 inches (-3.06).  Snowfall on the year was 8.4 inches… but records are kept on a seasonal basis.  From September 2008 until April 2009 – the total snowfall was 5.1 inches.  This was 4.8 inches below the average of 9.9 or 52% of the seasonal average.

There were 110 days in which some amount of precipitation (including a trace) fell in Okarche which set a record.  The average is 96.6.  There were 94 days with measurable precipitation (average 83.6).  In the 2009 calendar year… there were 8 days with snowfall which was about 2/3rds of the 12.1 average.  Measurable snowfall fell on 6 days (average is 7.3).

Dense fog was observed on 11 days (average 11.3).

Ice Pellets occurred on 5 days (average 4.1).

Freezing rain or drizzle occurred on 6 days (average 5.8)

There were 56 days with thunderstorms which was the highest amount since 1999.  The average is 49.4

Six days saw hail… the average is 2.6

There were 107 days where the wind was considered strong (reaching a peak of at least 30 mph).  The average is 97.2

Measurable snow was on the ground for four days… the average being 6.9.

Snowcast Event 5 – Update 2 – Midnight, Wed, Jan 6

No change to this evening forecast.  Looks like wave digging southeastward out of Montana area will move into the Midwest with associated lifting skimming the northeast part of the state.  Snowfall amounts are not expected to be significant… but a one inch or so dusting is possible over the northeast… with the most likely area to see accumulating snow over the far northeast part of the state.

Again… the main impact of this storm is cold air.  While some of the below zero numbers that were earlier expected may not occur… it still looks like many areas of the north and east may see numbers in the low single digits before it is over.

Not only does it appear that the airmass may not be as cold as expected… but there is little in the way of snowcover to the north and west of Oklahoma.  This may prevent record cold… but the airmass will still be some of the coldest of the year…

People in Oklahoma should be prepared for bitter cold temperatures to spread into the state during the next 12 to 18 hours.

010610

Snowcast Event 5 – Update 1 – Noon, Tue, Jan 5

Latest model trends show the strong short wave trough that will be digging southeastward out of the Plains and into the Midwest may come a little closer to Oklahoma – providing sufficient lifting for snowfall over the northeast part of the state.  While it still looks like amounts will be light… an inch or so looks likely – especially in the far northeast corner of the state.

Forecast soundings show an atmosphere capable of producing snow immediately after frontal passage around 6 pm on Wednesday… with the chance of light snow – and a brief burst or two – continuing until daybreak.

Main impact of this front will be the bitter cold air.

010610

Coldest Air Since 1996 Coming?

A very cold arctic airmass has been building and now looks ready to make a run at Oklahoma.  The models have been remarkably consistent in both the timing and strength of the cold air over the last several days.  It appears that the cold air will spill into the state during the afternoon hours on Wednesday, January 6th with freezing precipitation and light snow developing behind it.  There may be some accumulating snow in northeast or east central Oklahoma… but amounts should generally be light.  With this front – the main attention is going to be on the cold air.  Not only does this have a chance at being the coldest air of the season… but it may very well be the coldest air we have seen since 1996.

Low temperatures in Okarche are forecast to get down to the 1 to 3 degree range on Thursday and Friday nights.  If that happens… those will be some of the top coldest nights I have recorded in Okarche.  Currently… the top five looks this way:

1… (-2 degrees) – February 4, 1996

2… 1 degree – February 3, 1996

3… 3 degrees – March 3, 2002

4 (tie)… 4 degrees – January 6, 2004

5 (tie)… 4 degrees – December 8, 2005

Okarche, Oklahoma