Why wasn't a tornado warning issued?

I’ve seen several very recent discussions about why NWS Albany didn't issue or were late to issue a tornado warning on Wednesday's storms.  It always seems many are eager to go into a National Weather Service-bashfest.

First of all how does the warning process develop?

It starts with the Storm Prediction Center (SPC) located in Norman, Okla. The SPC is the  one who determines when a tornado watch will be issued, and where and which  counties will be included.  The SPC will communicate with the local NWS field offices involved in the watch area. After this, the tornado watch is issued.

 Once the watch has been issued, it’s up to the local field office to expand it or cancel it all together, if they think the watch is unnecessary. If there is a need for a severe thunderstorm to be warned, that is up to the local National Weather Service. It is also up to the local field office to issue a tornado warning if the conditions in the storm in question warrant it.

There are many reasons why tornadoes can go unwarned. Here are the major reasons.

 1)  I've been inside the Storm Prediction Center, National Severe Storms Laboratory, and a few local NWS field offices. Everyone in these places works hard and has long hours...this is especially true for the local NWS operational forecasters. They are often understaffed and their shifts are long,. For over a week the Northeast has had a lot of severe weather; when it is like this, the forecasters can work 80 hour  weeks or longer. .So it's not uncommon that forecasters can become significantly fatigued on their shifts. This can lead to human mistakes and errors. that lead to missing things including a potential tornado.

2)  In 2013 the NWS intruded changes in an effort to reduce false alarms.   The changes included both technological and how personal react. The radar algorithms work differently to allow for minute by minute input of observations. The goal of lessening false alarms means that forecasters wait until higher confidence exists before issuing warnings in order to decrease the chance they could be wrong.  Many times NWS forecasters now wait until a tornado has begun before issuing a warning more often than prior to this new policy, As radar technology get better and better,  more low key, generally weaker tornadoes are seen than ever before. These newly visible low-end tornado signatures on radar initiate low levels of confidence for forecasters trying to pick out which signatures features on radar are tornadoes, and which are not. These minor tornado possibilities often do not get warned due to lower confidence.

3)  . Sometimes, the radar simply cannot see them. The Earth's curvature causes radar beams to slope upward after they travel a lengthy distance. This may cause the radar beam to cut through the top of a storm. As a result it is often too high to discern if the storm is rotating.

 

4) Most of y'all know that traditional tornadoes develop from a rotating thunderstorm (also known as a mesocyclone) When a thunderstorm has a deep persistent rotating updraft they are called a supercell thunderstorm. Most of the time a traditional tornado will drop out of a wall cloud under the parent thunderstorm and lower to the ground. Once it touches the ground it is called a tornado.  Sometimes, tornadoes develop from the ground up. This type of tornado is called a landspout.

5)  A landspout requires a towering cumulus cloud to be present over a boundary of converging winds near the ground. This is typically found along a cold front or a gust front. The converging winds  from different directions collide with each other; this results in a small area of spin. sometimes this spinning vortex of air will reach the base of the cloud, once that occurs a landspout tornado is born. Landspouts are typically weaker and shorter lived than their traditional cousins.  Landspout tornadoes typically last only a few minutes; since a doppler Radar scan normally takes 4-6 minutes; the landspout could have formed and dissipated before the scan was completed.   Because radar can’t see rotation at ground level, many times a landspout can go undetected. When dealing with landspouts a tornado warning is often instituted late if at all.

 

 

6) Then there are QLCS tornadoes. When thunderstorms become organized, they are called a Mesoscale Convective System (MCS) A QLCS (Quasi Linear Convective System) is a type of MCS, where the complex of thunderstorms form a squall line. They typically form along a cold front. The armchair meteorologist reading this, know the squall line contains heavy rain, strong gusty winds, frequent lightning, and hail.  Sometimes brief little spin ups can occur along the leading edge of the squall line, .  These spin ups are called QLCS tornadoes. This type of tornado is often short lived and  weaker than traditional tornadoes, but not always. While  they can form and dissipate quickly and be hard to detect, they aren't landspout tornadoes.  This is because they form differently.  For a QLCS, as the cold front advances, it lifts warm air out ahead of it. which in turn forms the rain line, as the squall line develops the rain cools the warm air causing it to sink. This creates what is called a cool pool. The cool pool produces strong winds. These winds cause the squall line to bow out.  The cold and dense winds from the bowing line forces warm air to rise (loft); this process empties the space behind the bow, allowing a small area of low pressure to form. This area of low pressure draws in drier air above the squall line.  This process continues as everything develops and accelerates. This results in a tilted updraft to form over the top of the cold pool.  As this escalates a rear inflow jet forms.  As the process rapidly intensifies, vertical stretching of the updraft, which can lead to tornado formation.  Sometimes tornadoes can form within a subtle weak echo region on the forward flank of the bow containing high precipitation supercell characteristics.  There can also be so called bookend circulations at the tips of the bow echo that can also lead to Tornado occurrence.  QLCS tornadoes are most likely to form when the bow is intensifying.  QLCS tornadoes are difficult to detect and often can go unwarned.

 

 

 

7) Technical difficulties. Radar outages, communication outages, power surges/outages, and thunderstorms near or over the radar site, and terrain issues can cause problems.

There are other reasons a tornado can go unwarned....But this is why all warnings should be taken seriously. Far too many take severe thunderstorm warnings lightly.  I've seen this attitude lead to injury and death.  All severe thunderstorms are capable of producing a tornado in the right environment.  So never let your guard down, when a severe thunderstorm is approaching.

 

 

 

Why was there no tornado warning?

I've been getting personal messages  on the question...Why wasn't there a tornado warning on the tornado that touched down Tuesday in the village of Scotia,  20 miles northwest of Albany?

The simple answer is the NWS didn't know it was there.  But the bigger question is why didn't they know? The answer to that question is far more complex than you might imagine.

The Plains, Gulf States, and Midwest see a lot of tornadoes every year. The Northeast sees far less...but even at that we end up on average with around two dozen tornadoes every year.

The tornadoes out west typically form from a Supercell Thunderstorm. On my blog I've done several post on Thunderstorms and Tornadoes....here are two of them

One is about Supercells the other is about  Tornadoes .

I won't go into detail on Supercell tornadoes, you can read about that on the blog. But I will say, supercell tornadoes occur from thunderstorms with deep rotation in the storm; rotation meteorologists refer to as a mesocyclone.  The tornado descends out of that mesocyclone, and you can see that rotation on the radar.  The mesocyclone is easily seen on radar and nearly always has a tornado warning issued in association with it.  These are the type of tornadoes that occurred during the Alabama outbreak of 2011 , the Joplin EF-5 tornado, and the Picher, OK EF-4 of 2008.   The National Weather Service will always issue warnings on these.

While the Northeast does see Supercells and the rare supercell tornado....the typical tornado in the Northeast is a different type of storm.

 

 

The tornado that formed Tuesday near Scotia, was what is called a Squall line tornado. Squall line tornadoes are called QLCS (Quasi Linear Convective System) Tornadoes in the meteorological world. But they can also be called spin up tornadoes or bookend vortices.  

QLCS tornadoes are typically weaker than their supercell counterparts. The vast majority are EF-0 or EF-1...but a few have been as strong as EF-2 or even EF-3.  A squall line tornado is very hard to see on radar. There are a few reasons for this.

One) they are very short lived many times lasting only a few minutes. QLCS tornadoes form on the leading edge of squall line. along the squall line there is a lot going on and it's hard to keep track of it all. If it produces a V notch it is very hard to see.  They also form from the ground up not from the thunderstorm down. This often means the rotation doesn't reach the cloud, until after the tornado has formed.  

Two) current dopplar weather radar  has several limitations....It takes it five minutes to make a complete turn cycle. Many times the tornado can be gone when the radar comes around to see it.  

So even if the tornado hook shows up on radar on one scan. It would most likely be gone on the next scan. So there would be no time in which to issue a warning.   Another thing that makes squall line tornadoes hard to see on radar....it the angle of the radar beam..... the beam shoots into the sky at a 0.5-degree angle. ..we also have to take the curvature of the earth into account.  So the radar beam is  several thousand feet in the air at a moderate distance . It could very well be shooting over the top of the tornado.

 The tornado that formed last night in Northern Ontario County, near eastern Farmington close to Canandaigua, NY. was another example of a squall line tornado. NWS Buffalo issued the warming for the storm at 9:46 PM....which was just about the same time the tornado formed. The tornado was rated EF-0 and was only on the ground for a half-mile. So there was no time for anyone to really react to the warning in the first place.

 

 

You may be surprised to know during severe weather all media meteorologists as well as National Weather Service Meteorologists are in a closed, private chat session online discussing the situation that is unfolding.

Such was the case with last July's Madison County Smithfield, NY tornado, which killed four people.

There was a discrete mesocyclone heading for Syracuse, NY that had  the attention of meteorologist and the National Weather Service. The storm had a lot of very strong rotation with it. The Weather service in Binghamton did end up issuing a tornado warning on the storm near Syracuse at 5:39 p.m. The good news for Syracuse was the storm never spawned a tornado.

 Behind the mesocyclone there was an intense squall line...So while the mesocyclone never produced a tornado, the squall line did.  The tornado formed just below a 1,400-foot ridge in central Madison County about 7:02 p.m.  The tornado hit Smithfield before it even showed up on radar.   In Smithfield it killed  a mother, her 4-month-old baby and an older female relative.  It also destroyed a nearby house where  one man and his dog died.  The tornado moved away at 50 mph, heading down the north side of the ridge and dissipated at 7:06 p.m.. in less than  four minutes it came and went.

The day of the Smithfield tornado was very active.  The line ended up forming five tornadoes.

False alarms:

Many of the tornado warnings issued by the NWS never had a tornado in the first place. Roughly 75% of the warnings issued are in fact a false alarm. Because of this many times people will ignore tornado warnings when they are issued. If the NWS issued a warning for every possible spin up along a squall line the false alarm rate would be much higher.

This can create a dilemma for the NWS on how to warn on these scenarios. Issue a tornado warning after seeing possible rotation that could be a QLCS tornado. Don't issue a warning at all. Or just allow the severe thunderstorm warning to handle the brief spin up.

My view is don't issue the warning for a possible squall line tornado at all. This is why everyone should take severe thunderstorm warnings seriously.  Severe thunderstorms can and do produce tornadoes....that squall line heading your way, could form a brief tornado, with or without a warning.

The nature of QLCS tornadoes in the Northeast, is what makes them so extremely dangerous. Most of the time no one knows they're there until it's come and gone. They are difficult if not impossible to warn for......The entire line is capable of producing damaging winds with or without a tornado..