Very Rare Weather Phenomenon

[DNewman]

Hello guys , I'm sure this has been asked before. But what are some events in which there have been tornadoes in temperatures only in the 50s or 40s? And what type of setup would be needed to create a tornado in temperatures that are that cold? I know that as long as air aloft is colder than the air below, that this creates the buoyancy and instability needed to get a tornadic storm going. But what setups create cold weather tornadoes?
Last question is can there be a hailstorm and snow at the same time, or snow transition to a full blown hailstorm or vise versus? I know that is an EXTREMELY rare occurrence. But its happened before 1 time in my lifetime so far anyway. Thanks!

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[Brian G]

March 2nd, 2014 saw pretty unusual weather. There was a thunderstorm near Muskogee, OK in which hail accumulated on the ground while simultaneously sleeting. The temperature was 16F. On the same day in Branson, MO the SGF office issued a bona-fide severe thunderstorm warning for 1" hail with damage to cars expected. The warning also mentioned heavy sleet and 50mph winds. The temperature at the Branson airport was 19F at the time.

Hopefully someone else can chime in on the tornadoes, but the physics of the thermodynamic properties of the atmosphere is working against bouyancy driven tornadogenesis modes. When looking at a skew-t chart you've probably noticed that moist adiabatic lapse rates taken on more and more negative slopes as surface temperatures drop. That has a significant impact on the surface based bouyancy that can be realized.

 

[Jeff Duda]

I remember a case from Mike Umscheid (probably misspelling his name), probably somewhere around 2006-2008 where he documented tornadoes with surface temps in the 50s in western Kansas. Look up research performed by Jon Davies (a blog can be found here, but there are other pages he has, too) on "cold core tornadoes."

Cold-core tornadoes are pretty uncommon, probably more because no one is around to document them than anything, but they do happen. Keep in mind that the ingredients-based approach to severe storm forecasting does not include surface temperatures as a fundamental field. What's more important is lapse rates. As long as there is very cold air in the mid-levels, you can get better-than-pitiful CAPE even with surface temps in the 40s and 50s F. In general, you need to be very near or right under the mid-level core of a synoptic scale cyclone to have a chance at witnessing these types of events.

Anyway, Jon's blogs and research site (http://www.jondavies.net/publications.htm) will provide the information you're looking for.

 

[Paul Knightley]

This is an interesting discussion as the references thus far have been fairly Plains-centric, which is understandable. It is hard to get tornadoes with these low surface temperatures in continental areas as these low surface temperatures will typically be associated with a dry, continental airmass.
However, if you head to mid-latitude maritime climates, such as here in the UK, or the West Coast of the USA, it can be 'easier' for tornadoes to develop with low surface temperatures. For instance, we have a reasonable number of tornadoes each autumn and winter over here in polar maritime airmasses, where the air temps may be high 40s/low 50s, but the fact the airmass has traveled over a large part of the N Atlantic means the lower levels are modified and moistened, whilst it remains relatively cold aloft. Steep low-mid level lapse rates generate numerous showers and thunderstorms (low topped). The fact that this type of set-up typically is fairly dynamic means that strong wind shear can act on these showers and storms and help organisation, and sometimes tornadogenesis. An example of a fairly strong tornado was one which affected NW London back in December 2006, in the morning hours. A strong shortwave trough raced eastwards across southern England in the wake of a cold front. A line of heavy showers and thunderstorms developed an acquired QLCS-type morphology. Some imagery of the damage is in the video link below, along with my dulcet tones!

 

[calvinkaskey]

Here is video of hail/graupel in mid 40 temps in New York.

 

[Ethan Schisler]

Here is video of hail/graupel in mid 40 temps in New York.

Not exactly "rare". Wanna see rare? We had hail up here during the Groundhogs Day 2011 Blizzard in Northern Illinois. Few spots saw nickel size hail with convective snows. So to have hail occur with temps in the mid 40s isn't unusual. It happens all the time with elevated storms north of a warm front.

 

[GPhillips]

It's a very, very long web article by Jonathan Finch about the May 22 2008 tornadoes in eastern CO and southeast WY. If you go down to the meteorological discussion part, you'll see a description of the surface conditions and various surface plots showing temperatures in the 40s in southeast WY during the tornadoes.

http://bangladeshtornadoes.org/UScases/052208/22may2008terrain.html

 

[DNewman]

I remember a case from Mike Umscheid (probably misspelling his name), probably somewhere around 2006-2008 where he documented tornadoes with surface temps in the 50s in western Kansas. Look up research performed by Jon Davies (a blog can be found here, but there are other pages he has, too) on "cold core tornadoes."

Cold-core tornadoes are pretty uncommon, probably more because no one is around to document them than anything, but they do happen. Keep in mind that the ingredients-based approach to severe storm forecasting does not include surface temperatures as a fundamental field. What's more important is lapse rates. As long as there is very cold air in the mid-levels, you can get better-than-pitiful CAPE even with surface temps in the 40s and 50s F. In general, you need to be very near or right under the mid-level core of a synoptic scale cyclone to have a chance at witnessing these types of events.

Anyway, Jon's blogs and research site (http://www.jondavies.net/publications.htm) will provide the information you're looking for.

Thanks for that link and input. Its hard pressed these days to find research on these rare occurrenceces.

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[DNewman]

This is an interesting discussion as the references thus far have been fairly Plains-centric, which is understandable. It is hard to get tornadoes with these low surface temperatures in continental areas as these low surface temperatures will typically be associated with a dry, continental airmass.
However, if you head to mid-latitude maritime climates, such as here in the UK, or the West Coast of the USA, it can be 'easier' for tornadoes to develop with low surface temperatures. For instance, we have a reasonable number of tornadoes each autumn and winter over here in polar maritime airmasses, where the air temps may be high 40s/low 50s, but the fact the airmass has traveled over a large part of the N Atlantic means the lower levels are modified and moistened, whilst it remains relatively cold aloft. Steep low-mid level lapse rates generate numerous showers and thunderstorms (low topped). The fact that this type of set-up typically is fairly dynamic means that strong wind shear can act on these showers and storms and help organisation, and sometimes tornadogenesis. An example of a fairly strong tornado was one which affected NW London back in December 2006, in the morning hours. A strong shortwave trough raced eastwards across southern England in the wake of a cold front. A line of heavy showers and thunderstorms developed an acquired QLCS-type morphology. Some imagery of the damage is in the video link below, along with my dulcet tones!

I figured moisture would have a lot to do with tornado genesis ,when temps are that low. Usually when temps are only in the 40s & 50s ,theres a dry airmass in place. But in the case of a moist cold airmass(typical in southern states during fall &winter), then it can be possible, especially if theres a lot of strong wind shear. The key is getting the elevated storms to realize the wind shear and form updrafts strong enough to tilt that rotating horizontal shear and become a rotating storm capable of producing a tornado.

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[DNewman]

Not exactly "rare". Wanna see rare? We had hail up here during the Groundhogs Day 2011 Blizzard in Northern Illinois. Few spots saw nickel size hail with convective snows. So to have hail occur with temps in the mid 40s isn't unusual. It happens all the time with elevated storms north of a warm front.

When I said rare, I'm talking about hail & snow within the same storm going on simultaneously. I've seen a probably once in a lifetime severe t-storm warning,where half the storm was producing severe hail ,while the other half producing convective snow. Now that is a rather rare occurrence.

 

[ScottCurry]

Not sure how you define the same storm (cell or system), but in Colorado on May 16th of this year, quite a few of us were chasing tornadoes (and hail) one hour, and then driving through a blizzard the next hour. I though I might actually see a snownado

 

[David Conaway]

There is a book by Gary England ,"Weathering The Storm". Gary mentions an event during the winter of 1975 in Oklahoma where The surface temperatures were in the 40's and dew points in the 30's. During the night there were several damaging tornadoes that resulted quite a bit of damage and several deaths.

This does not fit into the category of storms simultaneously producing snow and tornadoes. However, it is still interesting none the less.

I should have looked First. There is already a thread started by Brett Roberts regarding this event in the 1970's events.

 

[DNewman]

There is a book by Gary England ,"Weathering The Storm". Gary mentions an event during the winter of 1975 in Oklahoma where The surface temperatures were in the 40's and dew points in the 30's. During the night there were several damaging tornadoes that resulted quite a bit of damage and several deaths.

This does not fit into the category of storms simultaneously producing snow and tornadoes. However, it is still interesting none the less.

I should have looked First. There is already a thread started by Brett Roberts regarding this event in the 1970's events.

Thanks I'll have to check that event and thread out. Never knew tornadoes could happen with dew points that low. Temperatures are one thing, but then moisture is what usually makes a big difference.

 

[Jeff Wright]

I once saw a very broad but pretty rapid rotation above a job site some years ago. No sever weather warnings of any kind however.

I wonder if it was a mesolow.

 

[John Farley]

On September 29, 2014, I witnessed a tornado around 12 miles west of Chama, NM, at an altitude somewhere around 8,000 feet above sea level. I approached the storm from the north, and my car thermometer never recorded a temperature higher than 48F. The tornado occurred with a supercell that was tracking along a more or less E-W baroclinic zone; I have no doubt there were considerably warmer temperatures on the south side of the storm. However, I was only a half mile or so north of the tornado when it occurred, so the ground temperature where the tornado occurred could not have been a lot different from what I was in. Warmer inflow, though, I would be pretty sure. You can read my account here:

http://www.johnefarley.com/chase92914.htm

Around the time the tornado occurred, Wolf Creek Pass around 50 miles NE of where the tornado occurred had the chain law in effect for commercial vehicles, I would presume as a result of some mix of snow, graupel, and/or hail. I would be pretty confident that in the higher elevations, the storm I saw did produce some snow or graupel. I have seen storms producing hail and snow or graupel (or both) simultaneously in nearby locations on at least three occasions in southwest Colorado (and I am not counting 9/29/14, since I did not personally witness snow or graupel). So it definitely can happen, though it certainly is more common in higher elevations. The most recent time I experienced this was the evening January 5 of this year in Cortez, CO, where a thunderstorm along a cold front was producing hail along its leading edge and snow in the trailing stratiform region of the storm.