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.