Isolated severe weather possible today…

While it doesn’t look like a significant severe weather outbreak will occur on Tuesday – thunderstorms / capable of producing hail and damaging winds / are possible in central and eastern Oklahoma.
 
A very strong upper system will move into the plains during the afternoon with a deep surface cyclone evolving in Nebraska and a strong mid-level jet segment spreading across Kansas. A dryline will take shape in western Oklahoma and approach the highway 81 corridor by late afternoon and early evening. There will be morning showers and thunderstorms that are likely to limit instability for most of the afternoon… however, it appears that enough low level moisture return and heating on the dryline will create sufficient instability for the potential of severe weather by late in the day.
 
In a somewhat unusual early season event, lifting associated with this system is likely to come from the area of the right rear quad of the mid level jet segment which will be favorably positioned over the dryline by late afternoon. Shear profiles support rotating storms which will enhance hail and wind potential and result in a non-zero chance of a tornado.
 

Otherwise, strong west winds behind the dryline and drought conditions are likely to cause extreme fire weather conditions over the western part of the state.

 
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Strong storm system moves across Oklahoma on Monday…

A fast moving, but very strong storm system, will pass over Oklahoma Monday (20th). We are going to have a hard time getting significant moisture back here before the dry line and cold front move through, but given the very strong lifting associated with the system – a few severe thunderstorms will be possible in eastern Oklahoma.

Meanwhile, a combination of continued drought – gusty winds and dry air will result in fire danger approaching extreme levels over western Oklahoma. We have had enough recent precipitation that fire danger may not get completely out of hand in central Oklahoma, but the risk will still be elevated by late afternoon.

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Cold air and mix of winter precip headed toward state…

A very complex weather event will be unfolding across the state over the next 72 hours… one which will bring some of the coldest air of the season, and a good chance of a mix of winter precipitation.

The first player in this event will be very cold air which is currently spilling southward out of Canada. This morning, temperatures are as cold as 11 degrees below zero in portions of North Dakota. The coldest part of this air will continue to push south and make it through most of Oklahoma by sunrise Saturday. Saturday stands to be a very cold day with most of the state seeing temperatures in the 20′s and a brisk north wind creating cold wind chills. Saturday night has the potential to be the coldest night of the winter so far as temperatures fall into the teens. As mentioned in other posts, the lack of dense snow cover between here and Canada will help keep temperatures about 10 to 15 degrees warmer than what an air mass of this type would normally do to us in the month of February.

Meanwhile, a strong storm system is getting ready to move into the southwest U.S. Yet another strong storm has been spinning just south of Baja California Sur. Previous model runs have indicated that as the southwest U.S. system approaches – the Baja Cal Sur system would eject northeast into the southern plains – bringing large amounts of moisture with it. More recent trends suggest that the southwest U.S. system will weaken some as it moves east and the Baja Cal Sur system will weaken and eject east toward the Gulf of Mexico. This track should limit the amount of moisture that is capable of moving north toward Oklahoma.

By Sunday afternoon, precipitation will begin to spread northeastward through western Oklahoma. With the cold air in place, forecast soundings suggest that this initial precipitation will fall in the form of snow. Given the fact that the deepest low level moisture is going to be cut off, this snow will be generally light – bringing at best – accumulations around an inch. Having had very cold air in place for over 24 hours, any snow that does fall will stick on contact.

Warmer air just above the surface will start to make a rapid move northeastward across the state during the early morning hours Monday. This will cause the precipitation to transition to sleet or freezing rain before ending Monday morning. In southeast Oklahoma, the precipitation may last until early afternoon resulting in slightly higher amounts of sleet.

While this does not look like a major event, the cold air combined with about a 12 hour period of off and on light freezing or frozen precipitation is going to cause the Monday morning drive to be interesting. A rapid warm-up Monday afternoon will cause most accumulated precipitation to quickly melt.

Several other storm systems will be following during the next two weeks, each will have to be monitored for their potential to produce winter precipitation.

Put the shovel down and step back!

I was at work Tuesday night when my phone started blowing up with people wanting to talk about the approaching winter storm. What winter storm? Channel 4 and Channel 9 are running with a significant winter storm which will bring at least 2-5 inches of snow to the metro by the end of the weekend I was told.

First of all, we are talking about a possible event that is five days down the road. Second of all, this forecast was being based on guidance data that has been more than questionable so far this winter. And third, despite a suite of products which produced accumulating snow in the state this coming Sunday and Monday – they were doing it with a weather pattern that is not conducive to heavy snow events in the OKC area.

On the topic of being five days down the road and questionable guidance. Wow. That is jumping out on a limb. The guidance produced by model data over the past few months has been down right abysmal at times. Model to model and run to run differences haven’t given me much reason to believe what is going to happen 48 hours down the road, let alone five days. Given the quality of model guidance so far this winter, I think I will wait until I see the whites of each systems eyes before I pull the trigger.

As far as what produces heavy snow in Oklahoma. Studies have shown that for the most part, one of the most important things that has to happen for Oklahoma City to see heavy snow is to have cold air in place before the precipitation begins. Getting cold air in here requires a cold air mass moving south and something to keep it cold (like dense snow cover from the arctic to Kansas). The more bare ground it gets to travel over – the more likely it is to modify. If you haven’t noticed… it’s been a warm winter around the country. When’s the last time you heard that Chicago was paralyzed with snow? When’s the last time you heard that numerous large airports around the country have been shut down? How many lake effect snow events have you heard of? When was the last big Nor’ easter? Flowers are blooming in the south and east – and smart money has shorted the orange crop. There just isn’t much in the way of snow pack across the U.S. and really cold air is having trouble staying – well – really cold.

The weather pattern does look like it’s going to become active over the next ten days. Numerous strong systems will be coming from the north Pacific… diving into the southwest U.S. and ejecting eastward across the plains. It is still February, and if one of these decides to take the right path – some snow could fall in Oklahoma. Climatology says that northwest Oklahoma and the Panhandle would be the most likely place to see snow. Until I see otherwise, I’m going to stick with several bouts of more beneficial rainfall for our area. I’ll have a plate of crow ready just in case….

 

Record rainfall / severe storms / snow?

The total precipitation in Okarche on February 3rd was 0.70 of an inch. This set a record for the date… beating out 0.10 of an inch set in 1990.

The beneficial rainfall – which temporarily puts us above normal for the year – came from a strong storm system which moved into the plains late on the 2nd and through the day on the 3rd.

Thunderstorms became severe in northwest Oklahoma during the early morning hours of the 3rd… producing hail up to quarter size and wind gusts to near 65 MPH. There were several small circulations noted on radar with the storms… and it wouldn’t be surprising if a few tornadic spin-ups occurred.

Severe thunderstorms redeveloped during the afternoon and produced hail near golfball size in Seminole. Hail larger than golfball size occurred near Sherman, Texas.

On the cold side of things… a full blown blizzard didn’t materialize – however, very heavy snowfall has occurred in Colorado and is spreading eastward across Nebraska and Iowa. Some snowfall totals in the central plains are expected to exceed a foot.

A lot of much needed rainfall occurred in Oklahoma – especially northwest Oklahoma – where 4.20 inches fell in Freedom. Southwest Oklahoma – where the drought remains the worst – came out on the short end of things. Less than 1/10th of an inch of rain fell in Harmon, Greer, Kiowa, Jackson and Tillman Counties.

We have enjoyed much warmer than normal temperatures during the past few weeks. This is coming to an end for a few days as cooler air heads south out of Canada and we return to seasonable normals.

Latest model guidance suggests an unusual evolving weather pattern. The system that is coming through the plains currently will leave a piece of energy over the central Rockies which will eject eastward across Oklahoma on Tuesday (7th). If this occurs, it may produce light / but accumulating / snowfall across the state. Because this is so many days out – and the system is somewhat of a strange evolution – I’m not counting on this being a snow event at this time. Something to watch….

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