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Blue Northers

By: Christopher C. Burt, 9:22 PM GMT on November 20, 2013

Blue Northers

A powerful cold front is expected to plow through Texas on Thursday dropping temperatures in Amarillo from the 70°s to 30°s in just a few hours. A little snow may follow. This front will be what they call in Texas a ‘blue norther’. They occur several times every year (and sometimes several times in a single month) from November through April. Here are some extreme examples of the phenomenon.

Origin of the term ‘Blue Norther’

Although the meteorological dynamics behind the sudden drop in temperature caused by the passage of a sharp cold front are common to many places in the world, the term ‘Blue Norther’ appears to have its origins and common usage as uniquely Texan. The Texas State Historical Society has this to say on the subject:

BLUE NORTHER. The term blue norther denotes a weather phenomenon common to large areas of the world's temperate zones—a rapidly moving autumnal cold front that causes temperatures to drop quickly and that often brings with it precipitation followed by a period of blue skies and cold weather. What is peculiar to Texas is the term itself. The derivation of blue norther is unclear; at least three folk attributions exist. The term refers, some say, to a norther that sweeps "out of the Panhandle under a blue-black sky"—that is, to a cold front named for the appearance of its leading edge. Another account states that the term refers to the appearance of the sky after the front has blown through, as the mid-nineteenth-century variant blew-tailed norther illustrates. Yet another derives the term from the fact that one supposedly turns blue from the cold brought by the front. Variants include blue whistler, used by J. Frank Dobie, and, in Oklahoma, blue darter and blue blizzard. Though the latter two phrases are found out-of-state, blue norther itself is a pure Texasism. The dramatic effects of the blue norther have been noted and exaggerated since Spanish times in Texas. But that the blue norther is unique to Texas is folklore.

The only error I can find in this description is that a blue norther is not solely an autumnal occurrence. In fact, they are just as common, if not more frequent, during the spring months and occur during the winter as well.



During the Dust Bowl of the 1930s, blue northers were mostly responsible for the dust storms that plagued northern Texas and other locations in the Plains. Above, is a blue norther-caused dust storm bearing down on Amarillo, Texas on April 14, 1935, a day known in history as ‘Black Sunday’. Photo from Library of Congress.

Extreme Blue Northers

One of the most extreme blue northers on record occurred just last April (2013) when a cold front plowed south into northern Texas and dropped the temperature at Amarillo from a high of 89°F on the afternoon of April 22nd to a coldest-ever-so-late-in-the-season temperature of 20°F by the morning of April 24th. This, however, does not entirely explain just how extreme and fast the drop in temperature was. After reaching a record high of 89°F at 4 p.m. on April 22nd in Amarillo the thermometer had fallen to 86°F at 7 p.m. just prior to the frontal passage. The wind was blowing from the SW at 14 mph. By 9 p.m. it was 58°F with the wind from the north at 37 mph with gusts to 55 mph. By midnight it was 38°F and by 2 a.m. on April 23rd it was 33°F and snowing. The temperature continued to drop to a low of 29°F by 6 a.m. So, all in all, a 60°F (33.3°C) drop in temperature over just about 12 hours.

But wait, there’s more! There were FOUR blue northers to hit Texas in just that single month of April 2013! The first one hit on April 8-9 with a similar drop in temperature at Amarillo from 89°F on April 8th to 29°F on April 9th with winds gusting to almost 50 mph. Another struck on April 14-15 dropping the temperature from 88°F to 39°F and then yet another struck on April 17-18th. Below is the surface analysis for 00UTC on April 18th:



Note the extreme range of temperature at this hour over northern Texas: 37°F and snowing in the NW tip of the Texas Panhandle (at Dalhart) while it was 94°F at a site just 200 miles to the south.

Here is the April 2013 monthly climate summary for Amarillo:



Perhaps the single most extreme blue norther in Texas history was that associated with the famous arctic outbreak of February 1899, the greatest such in the annals of U.S. weather history. In his classic weather book Texas Weather author George W. Bomar states that temperatures on the afternoon of February 3, 1899 had almost reached 100° at sites along the Rio Grande (specifically 99° at Fort Ringgold and 97° at Fort McIntosh—now known as Laredo). The cold front swept through Texas on February 8-9 and by February 12th the dome of high pressure was centered over the state with Abilene measuring a barometric pressure reading of 31.06”. Temperatures had fallen below zero F° across the northern two-thirds of the state with a minimum of -23°F at Tulia on February 12th. Fort Ringgold registered 7°F and McIntosh (Laredo) 5°F also on the 12th, all-time record low temperatures for the sites.

As is often the case with blue northers little precipitation accompanied the passage of the front.

Another infamous blue norther was that of November 11, 1911 although it was more notable in Oklahoma, Missouri, and points north than in Texas. More about this can be found here< on the NWS-Norman, Oklahoma web site as well as here on the NWS-Kansas City web site.

The blue norther expected to race across Texas on Thursday is not expected to be of historical significance with temperature drops of only about 40°F at most locations.

Christopher C. Burt
Weather Historian

Extreme Weather Temperature

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Wow Chris..
40 degree drop is pretty steep..
I lived in Lubbock during my High School years..
It sits on a caprock formation..
Always water problems there..
Last I heard the city is working with USDA on water resourcing plan and a gov. co-sponsered project implementation.
Anyway..
The only weather I ever remember paying attention to..
Was the dust storms..
They made everything miserable..
Thanks again for the interesting post.. :)
Thanks, Chris. Fascinating as always.

I've always been keen on experiencing every type of severe weather event there is. There are only a few left on my bucket list, but one that I marked off years ago was a true Texas blue norther. I lived in Texas for a while, and vividly remember getting excited at the forecast of a blue norther in mid-December. I don't recall the exact details of my first, so it wasn't anything historic. But I recall being amazed as the weather went from Florida-like--warm and humid--to Wyoming-like (cold, dry and windy) over the span of just a few hours.

(A month later--January 1982--I just happened to be driving from Houston to Cleveland when that deep, record-breaking cold snap happened. I went to bed in a Texarkana motel to temps in the 60s, and awoke to flurries and mid 20s. [I even managed on that trip to unwittingly pass through Cincinnati on the very day of the infamous NFL "Freezer Bowl", which featured a wind chill of -37F.])
I love being a Texan!
There was a 58 degree drop at Daytona Beach FL from the afternoon of Jan 20, 1985 to the morning of January 21. 73 to 15 degrees. The high temperature on Jan 20 was 5 degrees above normal. It's the only example I know of an above normal afternoon reading falling to an all-time record low the next morning.

Jan 20 1985 at Daytona Beach


Jan 21 1985 at Daytona Beach

Note that while the coldest hourly reading was 16 degrees it did reach 15 that morning.

Orlando FL had a 54 degree drop from the afternoon of Jan 20th to the morning of Jan 21st. Orlando went from 73 to 19, but that did not break their all-time record of 18 set in December 1894.

Melbourne FL had a 52 degree drop from 75 to 23.

I bet temp drops of over 50 degrees would qualify as a strong blue norther in TX. Wild that they happen in central FL too!
Donnie, I remember that freeze well. I was living in Indialantic, just across the lagoon from Melbourne. We had two huge West Indian Mahogany trees in our yard, as well as several large grapefruit and orange trees. That freeze killed all of them. It sucked for me, because I was 12, and I loved sitting in my treehouse in one of those Mahoganies.
LOL - I remember the first experience I had with this kind of weather event after moving to central OK.

Left to go shopping in 70 degree F weather, only to emerge a couple hours later to below freezing temps and a brisk breeze from the north. The shorts and t-shirt I had on were, needless to say, completely inadequate.

The one that occurred on 11/11/11 still holds the daily record high and low temperature recorded in OKC for that day.
I don't remember the exact dates but in late December (12/20 or so)
1990, bitter cold arctic air slowly oozed south in the western Plains states
and 70F or so air in Nebraska was replaced by 10F or so air the next day. It took two or three days for the front with this to reach south Texas but it ultimately got south of Brownsville. It was interesting to watch the stations in the plains slowly go under. I suspect this is a much larger scale case of the cold air damming that happens on the eastern seaboard when cold air gets trapped with northeast flow and oozes southwest to sometimes central GA. But the Rockies can do this with synoptic scale arctic air masses. The Appalachians are too low.


Conversely it's hard to get shallow bitter cold arctic air over the Appalachian mountains from the west and the eastern seaboard coastal plain stations are a hardiness zone or more warmer than Ohio Valley or TN Valley stations at similar latitudes.


I've never lived in TX but remember reading the saying

"Somtimes t'aint nuttin 'tween Texas and the North Pole but a bobwire fence" in reference to these northers.


Thanks for this blog entry. Low level cold air and it's behavior is of interest to me as a hobby gardener as well as a hobby forecaster.

Quoting 4. DonnieBwkGA:
There was a 58 degree drop at Daytona Beach FL from the afternoon of Jan 20, 1985 to the morning of January 21. 73 to 15 degrees. The high temperature on Jan 20 was 5 degrees above normal. It's the only example I know of an above normal afternoon reading falling to an all-time record low the next morning.

Jan 20 1985 at Daytona Beach


Jan 21 1985 at Daytona Beach

Note that while the coldest hourly reading was 16 degrees it did reach 15 that morning.

Orlando FL had a 54 degree drop from the afternoon of Jan 20th to the morning of Jan 21st. Orlando went from 73 to 19, but that did not break their all-time record of 18 set in December 1894.

Melbourne FL had a 52 degree drop from 75 to 23.

I bet temp drops of over 50 degrees would qualify as a strong blue norther in TX. Wild that they happen in central FL too!



In Tallahassee Sunday morning Jan 20, 1985 was in the low 30s. When the arctic front came through, with gusty winds the radiation inversion mixed out and we shot up to about 50 at dawn. Then the cold advection lowered us to about freezing but with wind. Cold rain changed to freezing rain, ice pellets and light snow. Little accumulation. Late afternoon temperatures were slightly below freezing under clouds and wind with spits of snow. A secondary front came through and temperatures plummeted to the teens before midnight bottoming out at 6F with 30 knot north winds Monday morning the 21'st. Under full sun Monday we reached 28F. FSU was closed because of heating failures and broken pipes in many of the buildings. I had a broken knee ligament from a skiing accident (crippled for three months) and could not walk or drive around to see what was going on or defend my garden against an indefensible deep deep freeze. I do remember hobbling home (I could slowly walk with a knee immobilizer) and stepping on fire ant mounds frozen solid and thinking viciously that the little suckers could not, for once come out and get me. There was thick (half inch) ice on the running stream next to my apartments. It was by far the coldest day I saw in TLH and one of the fifty coldest of my life ANYWHERE (and I went to Penn State and lived in DC and NJ most of the rest of my life)

Oh yeah, I remember that day!


(( I posted the same thing on Dr Master's blog ))

This was the cold outbreak of the century for North Florida. I've often wondered why the 1980s had more arctic outbreaks than the 50s,60s, 70s, 90s or aughts??

Another geographic region that gets strong cold blasts trapped by mountains, is South America. The Andes are even higher than the Rockies and a polar anticyclone over the southern part will drive a strong cross isobar blast amazingly far north some winters. As far as I know this is the only place in the world where cold fronts cross the equator (from the south)

I wonder how much stronger these would be if South America were not so narrow in its southern extents.
Lake Pontchartrain Freezes "South Shore", near NOLA - December 26th, 1989

Our Last tru Blue Norther'

Growing up in south La. we just called them northers.
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