An EF-2 tornado touched down at 9:32 this morning in the town of Revere, Massachusetts just north of Logan Airport. This was the first tornado to strike Suffolk County, Mass since the modern tornado record began in 1950! There are a few things about this storm that are worth noting.
The storm exhibited weak rotation for quite some time prior to tornadogenesis. Rotation never reached an “alarming” level but was certainly at a “we should watch this storm” level. 3 minutes prior to tornadogenesis at 9:29 a.m. radar shows a fairly broad/weak low level mesocyclone.
930 UTC KBOX 0.5 BR/BV/ZDR/CC clockwise from top left.
By 934 UTC doppler radar has confirmed that a tornado touched down. Not only is there 85 knots of gate-to-gate delta-V there is a classic and clear tornado debris signature. All the criteria are met here with high Z, CC <0.8, strong low level rotation, and ZDR near of below 0.
934 UTC KBOX 0.5 BR/BV/ZDR/CC clockwise from top left.
By the 939 UTC volume scan the low level mesocyclone has virtually disappeared – though lofted debris remains in the sky (>2000 ft AGL) from the prior tornado touchdown.
939 UTC KBOX 0.5 BR/BV/ZDR/CC clockwise from top left.
Unfortunately, the tornado warning wasn’t issued until 9:44 a.m. – a full 10 minutes after radar detected lofted tornado debris!
NATIONAL WEATHER SERVICE TAUNTON MA
944 AM EDT MON JUL 28 2014
THE NATIONAL WEATHER SERVICE IN TAUNTON HAS ISSUED A
* TORNADO WARNING FOR...
SOUTH CENTRAL ESSEX COUNTY IN NORTHEAST MASSACHUSETTS...
* UNTIL 1030 AM EDT
* AT 944 AM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED
OVER SWAMPSCOTT...OR OVER SALEM...AND WAS MOVING NORTHEAST AT 55
* SOME LOCATIONS IMPACTED INCLUDE...
MIDDLETON...MANCHESTER AND NAHANT.
TAKE COVER NOW! DO NOT WAIT TO SEE THE TORNADO. GO TO A BASEMENT OR
INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING...AWAY FROM
WINDOWS. IF IN A VEHICLE...A MOBILE HOME OR OUTDOORS...GET TO THE
CLOSEST SHELTER. PROTECT YOURSELF FROM FLYING DEBRIS.
So what went wrong?
It would have been virtually impossible to provide any lead time with a tornado warning in this situation. The tornadic circulation developed and fell apart within about 10 minutes. What is bizarre is that the tornado warning didn’t come out until 10 minutes after the tornadic signature was on radar.
Additionally, the National Weather Service’s Warning Decision Training Branch guidance for tornado warnings says that a tornado debris signature – like the one seen today in Revere – confirms a tornado was or is on the ground.
What the TDS will give you is confirmation of a damaging tornado, and that when properly trained to know what you are looking at, this signature is as good if not better than a spotter report of a tornado. – WDTB training document
Even when the Tornado Warning was issued, in my opinion, there should have been language in the text indicating radar confirmed a tornado was – at some point – on the ground. If not in the warning text than on NWS Chat or other means of dissemination.
Additionally, after the fact when it was clear a tornado did touch down based on the debris signature, local media waited more than 2 hours for the National Weather Service to say a tornado touched down. 2 hours of storm coverage was spent pondering whether it was a tornado are whether it was a microburst. Why? If radar confirms there is a tornado on the ground why are we waiting? Just say it’s a tornado and provide details about the tornado (path length, width, intensity) after the fact.
Some people wondered if the Storm Prediction Center dropped the ball by not issuing a tornado watch prior to the Revere tornado. In my opinion they did not! This was a very localized case that was not widespread enough to warrant a watch. The Storm Prediction Center and the National Weather Service both did a nice job mentioning the potential for isolated tornadoes. The forecast 24 hours to just prior to the event was spot on. We were mentioning the potential for tornadoes here in Connecticut as well given the setup and the way things looked to us.
This isn’t the first time a Tornado Debris Signature has shown up on radar here in the northeast and wasn’t mentioned by the NWS in warnings or statements. There were 2 cases in Albany last year and a third in Pennsylvania in 2012 where TDSs were present on radar and they weren’t mentioned in statements. The killer EF-2 tornado in Madison County, NY earlier also had a tornado debris signature – yet was not even covered by a tornado warning!
The National Weather Service has invested a lot of money in fantastic technology that can help us get more timely and accurate warnings to the public. SAILS and dual polarization technology is huge! We have the technology and the science at our disposal – let’s use it!