Tag: severe weather

We’re Watching The Skies Over Connecticut

SPC Hourly Mesoscale Analysis

As of 3:20 PM there are two Severe Thunderstorm Watches covering Northern Connecticut. Both run until 9:00 PM (though they’re sometimes cancelled before the expiration).

PRIMARY THREATS INCLUDE…
SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

As mentioned earlier, the Lower Midwest is primed for tornadoes again. Tornadoes are unlikely in Connecticut today.

If you’re interested in geeking out, this page from the Storm Prediction Center leads to all the forecast and observed parameters for the Northeast today.

Remember, forecasts age quickly. Don’t depend on my blog post for current storm info.

Weatherwise Tuesday Looks Bad Too

Storm Prediction Center May 20 2013 1730 UTC Day 2 Convective Outlook

This information is current as of Tuesday morning at midnight. When you look for a forecast, look for current information.

todayTerrible day today in the Southern Plains. 18 reported tornadoes. Around 100 reports of large hail. Nearly two dozen children killed at school. Thirty others dead as well.

The storms were well forecast. The area was warned. Some storms are beyond simple defenses.

Folks who live in Oklahoma hear warnings all the time. I suppose it’s easy to dismiss them and think, as has always been the case for most people, the storm will hit someone else. That was especially true because Monday’s severe weather set up in about the same place as Sunday–unusual.

mcd0741Tonight concern is centered from the Missouri bootheel through Eastern Illinois and Western Indiana plus a little corner of Kentucky and Tennessee. Tuesday it will be Northeast Texas (maybe the Dallas metroplex) into Northern Louisiana and Southern Arkansas under-the-gun.

Here’s the lead from the Storm Prediction Center’s tech discussion. Read what you can. I’ll follow with a translation to English.

CURRENT INDICATIONS ARE THAT PRE-FRONTAL CONVECTION DURING THE DAY 1 OVERNIGHT HOURS WILL RESULT IN OUTFLOW BOUNDARIES LOCATED WITHIN THE WARM SECTOR AT THE START OF THE PERIOD…AND THESE ARE EXPECTED TO PROVIDE AN ADDITIONAL FOCUS FOR SUBSEQUENT THUNDERSTORM REDEVELOPMENT DURING THE DIURNAL HEATING CYCLE ON TUESDAY.

A front is moving in from the west tonight. Thunderstorms will fire up ahead of it. Cold air, outflow from the storm, will pour down from the cloudtops.

The cold air will dislodge warm parcels near the ground which will keep the thunderstorm cycle alive.

Here in Connecticut we sometimes see storms refire from outflow, but there’s little skill in predicting which exact one. That’s why most watches and warnings you get from real people (like on TV) will talk more about general conditions than saying, “If you live on Flugle Street hit the basement now.”

We can nowcast these cells, not forecast them.

Tuesday in the Lower Midwest will be muggy. Overhead the jet stream will run a moderate speed, helping to draw parcels of humid air skyward from the surface.

ALTHOUGH LOW-LEVEL WINDS WILL GENERALLY BE AOB 20-25 KT…FORECAST SOUNDINGS INDICATE WINDS WILL INCREASE AND VEER WITH HEIGHT IN RESPONSE TO THE PROGRESSIVE SHORT WAVE TROUGH…PROVIDING SUFFICIENT VERTICAL SHEAR FOR ORGANIZED CONVECTIVE STRUCTURES INCLUDING A FEW SUPERCELLS TO DEVELOP. VERY LARGE HAIL…DAMAGING WIND GUSTS…AND POSSIBLY A FEW TORNADOES WILL BE POSSIBLE…ESPECIALLY WHERE BOUNDARY INTERACTIONS MAY ENHANCE LOW LEVEL SHEAR/SRH. ACTIVITY IS EXPECTED TO GROW UPSCALE BY EVENING WITH SEVERAL QLCS/S FORMING WHICH MAY RESULT IN AN INCREASE IN WIND DAMAGE POTENTIAL. ACTIVITY IS THEN EXPECTED TO WEAKEN GRADUALLY BY 03-6Z AS THE SHORT WAVE TROUGH LIFTS NEWD AWAY FROM THE REGION AND DIURNAL COOLING BEGINS TO STABILIZE THE BOUNDARY LAYER.

There won’t be much wind on the ground, but it will increase and change direction as it climbs. Wind shear is part of the formula for supercells.

The discussion mentions QLCSs, Quasi-Linear Convective Systems. These are storms which pack a line of damaging winds on the leading edge. Maybe you heard me mention “bow echoes” on TV? That’s part of the QLCS life cycle.

The worst times for storms will be Tuesday afternoon and evening with things finally simmering down before midnight.

Tornadoes are nasty. They often pack stronger winds than the strongest hurricanes. The whole concept of safety in a tornado is more relative than absolute. Tornadoes can grow stronger than any of our prep, as happened today.

I watched a man interviewed on CNN tonight. He carried all his worldly possesions in a laundry basket. He felt terrible for those who suffered more. He considered himself lucky tonight in Oklahoma.

I just can’t imagine.

Stormy Saturday

Social media is a real puzzle for old school media like FoxCT. If we satisfy people on Twitter or Facebook, where we make no money, will they stop coming to the TV station? That’s no trivial matter!

This has been an interesting weather day in Connecticut. Severe Weather, well forecast over the last few days, headed in.

I’m still stuck at home, but I had a text conversation early this afternoon with Dan Amarante at FoxCT. He was getting ready for a busy day and lots of cut-ins.

“I will handle Twitter,” I typed.

Social media is a real puzzle for old school media like FoxCT. If we satisfy people on Twitter or Facebook, where we make no money, will they stop coming to the TV station? That’s no trivial matter!

The prevailing wisdom is by engaging our audience on a variety of platforms you will come back to the mothership for your TV news viewing. That might be 100% wrong. I don’t think anyone really knows.

I started posting on my Twitter and Facebook accounts, the Fox On Fox page and @WeatherCT Twitter account.

The amount of data available at home is amazing. Radar, surface obs, computer guidance — yup. I even have an account on the Weather Service’s chat server. It is surprisingly valuable. Most of our competitors aren’t using it. They should.

The watches and warnings for Connecticut come from three Weather Service Offices and the Storm Prediction Center. It’s days like this where the lack of coordination between offices becomes a problem. Warnings artificially end where an office’s jurisdiction ends, even if it should extend farther.

I tried my best to relay them as quickly as possible. Living in a 140 character world is tough.

No tornadoes in Connecticut, though two were confirmed in New York City close to the Belt Parkway and JFK. Very unusual.

We had seven reports of significant weather related damage in Connecticut, though most people saw nothing worse than lightning and sporadic heavy rain.

On Twitter someone asked, “Do you get paid to do that?”

No. It’s just what I do.

A Little Inside Baseball On Today’s Storm Coverage

There’s little comparison shopping during a storm like today’s. You just have to hope the folks watching were satisfied and you made some friends who’ll remember you next time they need this kind of info. That’s all you can do. Then you pray audience follows performance.

Were we on for two and a half hours today? I think so. This kind of wall-to-tall coverage sneaks up on you.

The forecast was pretty straight forward. I write a little columnette in the Hartford Courant. Here’s what was written yesterday evening and hit the doorstep this morning:

The Storm Prediction Center has an odd way of giving us a heads up on severe weather. As of late Tuesday evening we are under a “slight risk” of severe weather for Wednesday. When SPC says “slight risk” you can read it as “significant risk.” I do and I probably follow their work a little closer than you. Strong, possibly severe, storms this afternoon will usher in cooler, drier air for Thursday.

So, this weather was no surprise to any of us (even at the other stations). Dan Amarante says he talked about it on-the-air over the weekend. That’s a pretty decent lead time.

Once you know about the weather you’re supposed to get ahead of it. Joe Furey stayed late. I came in early. Dan just came in (on his day off).

Rachel, off to visit her grandmother out west, will hopefully board her flight only five hours late! Bradley is the last place she wanted to be. I can relate.

The Severe Thunderstorm Watch was issued at 1220 PM. It followed a Mesoscale Discussion this morning which gave a 95% chance of the watch being issued! Like I said, conditions were straight forward.

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CONNECTICUT
MASSACHUSETTS
NORTHEAST NEW JERSEY
SOUTHEAST NEW YORK
RHODE ISLAND
COASTAL WATERS

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1220 PM UNTIL
900 PM EDT.

HAIL TO 1.5 INCHES IN DIAMETER…THUNDERSTORM WIND GUSTS TO 70
MPH…AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

We went on live around 2:00 PM covering the beginning of the scheduled program. Joe Furey did handled that one and in two minutes set the stage.

At 2:30 PM I went live and then a funny thing happened… we didn’t go off! The storms were vicious. There were reports of large hail and wind damage. The cells were living up to expectations.

When the light on the camera came on I had no idea how long I’d be on. I never expected it to last until 5:00 PM.

Dan ‘drove’ the graphics equipment. Joe kept giving me on-site information coming into the newsroom.

It’s possible to do this kind of coverage by yourself, but its best when the talker concentrates on what he’s saying and the others feed him info. I prefer to watch the monitor and have the graphics lead me. That’s what Dan and Joe did.

There are a lot of standard things to say: how to stay protected, what the colors on the radar mean, what’s expected. It’s also important to have an understanding of the state’s geography. Mentioning West Farms Mall is probably more meaningful than mentioning any of the three towns it straddles.

Dana and Sara, two producers, were in the control room. Along with them were a director, camera operator and audio engineer. They are used to following a set rundown. Not today. Everything was seat of the pants.

Alison and Brent anchored on-set. They did all the interviews, but on a day like today they let the weather folks do the heavy lifting.

It really is a team effort and its made better when the team has a singular goal.

There’s little viewer comparison shopping during a storm like today’s. You just have to hope the folks watching were satisfied and you made some friends who’ll remember you next time they need this kind of info. That’s all you can do. Then you pray audience follows performance.

Postscript: My wife found it funny my tissues ended up on the desk with me. For 2.5 hours my mind was off my cold.

I’m Expecting To Be Busy With The Weather

The Storm Prediction Center was we’re in the ‘slight risk’ area for severe weather today. Whereas most government warnings overstate the problem SPC’s are usually too conservative. A slight risk area nearly always leads to a Severe Thunderstorm Watch area. Conditions certainly favor that.

SPC’s usual pattern is to post the risk area then later discuss the area in more detail with a Mesoscale Discussion. The only MD in effect as I type is for Maine.

The Storm Prediction Center says we’re in the ‘slight risk’ area for severe weather today. Most government warnings overstate problems. SPC’s preliminary advice is usually too conservative. A slight risk area nearly always leads to a Severe Thunderstorm Watch area. Conditions certainly favor that.

SPC’s usual pattern is to post the risk area then later discuss the area in more detail with a Mesoscale Discussion. The only MD in effect as I type is for Maine. MDs lead with watches.

…MID ATLANTIC/NORTHEAST… A BREAK FROM THE RECENT HEAT IN THE EAST WILL EVENTUALLY COME IN THE FORM OF A WEAK COLD FRONT THAT WILL CROSS THE APPALACHIANS TODAY AND MOVE OFF THE MID ATLANTIC SEABOARD BY EARLY SATURDAY. A VERY MOIST AND INCREASINGLY UNSTABLE AIR MASS WILL PRECEDE THE FRONT THIS AFTERNOON WITH SBCAPE LIKELY TO EXCEED 2000 J/KG FROM NC TO NYC. TSTMS SHOULD BECOME MORE COMMON AS CONVECTIVE TEMPERATURES ARE BREACHED EARLY AND LIFT WITH THE FRONT AND UPPER TROUGH SPREADS EAST ACROSS THE SPINE OF THE APPALACHIANS.

If/When we get storms the largest threat will be downburst winds and, of course, the lightning itself! It’s a bigger deal because of all the outdoor graduation ceremonies scheduled. People and lightning don’t mix!

The good news is there’s more comfortable air on the other side and it should be in place by Saturday morning.

See you on the TV this afternoon. I’ll be wrangling the weather on the FoxCT News at 4.

Another Day With Severe Potential

Yesterday I wrote about Monday’s chances for severe weather. I said it would be awful or nothing–no middle ground. It was nothing.

There is potential for severe weather again today! The setup is somewhat different. The atmosphere isn’t quite as explosive, but there will be a spark. That was missing on Memorial Day.

The most likely time for storms would be late afternoon until midnight… and maybe a little later.

Yesterday I wrote about Monday’s chances for severe weather. I said it would be awful or nothing–no middle ground. It was nothing.

There is potential for severe weather again today! The setup is somewhat different. The atmosphere isn’t quite as explosive, but there will be a spark. That was missing on Memorial Day.

The most likely time for storms would be late afternoon until midnight… and maybe a little later.

The Storm Prediction Center says there’s hardly any risk for tornadoes, but a few towns getting gusty wind and large hail is to be expected. SPC is also saying:

A WARM/MOIST/DESTABILIZING AIRMASS IS FORECAST TO BE EVOLVING BY MIDDAY AHEAD OF THE ADVANCING COLD FRONT ACROSS THE NORTHEAST/MIDWEST REGION. AS THE FRONT — AND ASSOCIATED UPPER TROUGH — PROGRESS EWD WITH TIME…SHOWERS AND THUNDERSTORMS ARE FORECAST TO INCREASE WITHIN MULTIPLE BANDS…CROSSING OH AND SHIFTING INTO PA/NY/WRN NEW ENGLAND THROUGH THE AFTERNOON. EVENTUALLY…BANDS OF STORMS SHOULD CROSS THE APPALACHIANS AND MOVE INTO SRN NEW ENGLAND AND THE MID-ATLANTIC REGION.

Tuesday’s trigger is a cold front. It will be much drier once that passes.

Severe Weather Memorial Day: The Barrel Of Gasoline Analogy

Let’s say you’ve got a barrel of gasoline sitting on your front lawn. No spark, it’s harmless. Add a spark and it’s big trouble.

Memorial Day will feature that barrel of gasoline sitting on Connecticut’s lawn. The question is will there be a spark?

The Storm Prediction Center has a long complex discussion about just this subject. They list all the pluses and minuses and then finally say,

THE CONDITIONAL THREAT IS VERY HIGH FOR SEVERE WEATHER.

It took me years to understand sentences like that. SPC is saying we can’t be sure there will be severe weather, but if there are any thunderstorms at all they are likely to be severe!

I consider myself a good forecaster, but I would be a fool to not take advantage of SPC’s specialized expertise on days like this.

I’m working tomorrow. My most important job will be radar watching. These storms are more likely to fire up overhead than move in. Warning times may be limited… if they come at all.

Where To Find Tornado Info

SPC’s site is a nerd’s delight! It is loaded with maps, charts and numbers. All the secrets are hidden in plain sight if you know where to look.

From the Ohio Valley south this is an explosive night! Over 50 tornado touchdowns have been reported so far and the day is far from over. There is a continuous line of Tornado Watches from Central Ohio to the Florida Panhandle!

I sent texts to two friends in the Nashville area. I told them the storms near them deserve respect. They get it.

If you’re interested in severe weather the best place to go is the Storm Prediction Center‘s own site. Severe weather forecasting has benefited from digital technology and instant communications more than any other forecast discipline.

SPC’s site is a nerd’s delight! It is loaded with maps, charts and numbers. All the secrets are hidden in plain sight if you know where to look.

The SPC homepage is built around a map with rollover menu. No clicking necessary. Just mosue from menu item to menu item to see the map instantly populated with data.

Clicking the mesoanalysis tab opens another map with the country divided into zones. Some zones are fixed by geography. Others float in response to current or soon-to-be-current conditions. Each can be filled with the parameters most useful in predicting severe storms.

As the weather progresses and new storms look likely SPC issues Mesoscale Discussions. In these discussions forecasters lay out their thinking behind the watches to come. These are often very technical and cloaked in arcane terminology and even more obscure abbreviations.

I’ve been doing this nearly 30 years and I still scratch my head from time-to-time!

SUPERCELLS MOVING THROUGH ERN KY WILL CONTINUE THROUGH AN ENVIRONMENT VERY FAVORABLE FOR STRONG TO VIOLENT TORNADOES AS THE LLJ STRENGTHENS TO IN EXCESS OF 60 KT. LAST VWP DATA FROM JACKSON KY INDICATE VERY LARGE 0-1 KM HODOGRAPHS WITH STORM RELATIVE HELICITY ON THE ORDER OF 800 M2/S2 AND 500 J/KG MLCAPE. THESE PARAMETERS ALONG WITH THE DISCRETE NATURE OF THE CONVECTION WILL CONTINUE TO PROMOTE A THREAT OF TORNADOES…VERY LARGE HAIL AND DAMAGING WIND NEXT FEW HOURS.

That one I understood entirely.

SPC is also the keeper of the storm reports. What’s listed is often unverified and subject to revision, but still a good indicator of what’s going on. There are over 300 reports today including tornadoes!

When tornadoes are on the ground or severe storms are spotted the responsibility gets moved to local Weather Service offices. Following details becomes more random and difficult since offices cover oddly shaped areas. The Storm Prediction Center still watches, but with more of a hands off attitude.

If this site would have existed when I was growing up I might have never left the house!

The Tragedy At The Indiana State Fair

It’s easy to look at the radar and think everything is obvious. It is not. That was proven this weekend in a tragic loss of life.

Like you I have been dumbfounded after seeing the video from the stage collapse this weekend at the Indiana State Fair. There is a blog with really excellent analysis of what happened, including a play-by-play of the radar imagery available.

If you’ve been watching Rachel and me on FoxCT you probably remember a storm last month where we pointed out exactly the same feature that caused the trouble in Indiana: a gust front.

These are easily visible on radar, but only if you know what you’re looking for!

After reading these storms were being monitored by a public safety officer on his smartphone Rob White, the blogger who did the analysis, added:

On his smartphone? Really, the Special Operations Commander and fair Executive Director were monitoring the potential for incoming severe weather on a smartphone? I’m sure many of the fans out in the crowd were as well, but most of them weren’t expecting to make a life or death decision on it.

This comes back to a point that I’ve tried to make many times on this blog. When it comes to severe weather safety and preparedness at a major public event, the organizers and/or managers of such an event need to leave it to a professional to monitor the weather for them – not a layman watching the weather on a smartphone (or even on a computer via the internet for that matter).

I couldn’t agree more. It’s easy to look at the radar and think everything is obvious. It is not. That was proven this weekend in a tragic loss of life.

This is the video of a tragic event. Lives were lost onscreen. You should consider this before clicking play.

About Those Storms I Forecast (photo)

We got a bunch of interesting weather pictures tonight, but this might be the most interesting!

Last night I posted a blog entry about the storms I was worried about for today. They appeared right on time! They were doozies. We had reports of hail and substantial downpours that flooded some low lying areas. Cloud-to-ground lightning set off house fires!

Interesting weather pictures were common tonight. This might be the most interesting! It comes from Jess and Mike in Lisbon, CT (where there were no severe storms).

You’re looking at a mammatus cloud.

Mammatus, also known as mammatocumulus (meaning “mammary cloud” or “breast cloud”), is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a cloud. The name mammatus, derived from the Latin mamma (meaning “udder” or “breast”), refers to a resemblance between the characteristic shape of these clouds and the breast of a woman.

More unusual than rare they are often associated with severe weather. A common emotion when seeing mammatus clouds for the first time is fear. Actually that fear might not leave even after a first sighting!

I Keep Track Of The Weather

“Southeastward moving.” That’s the scare line for me. Our strongest storms move northwest to southeast.

I don’t know how other people do their jobs, but I keep track of the weather while I’m off-the-clock. The atmosphere has a rhythm. You want to stay in the rhythm. I look at maps, usually briefly, all the time.

The Storm Prediction Center just issued Moday’s national outlook. We’re squarely inside the “slight risk” area for severe storms.

Slight doesn’t sound bad, but it’s better than 50/50 if you’re in the slight risk area you will get a severe weather box later in the day! I’ve been doing this a long time. There is a rhythm.

I’m going to post SPC’s technical discussion, but feel free to skip this section. It’s full of jargon and technical terms plus nearly all the Weather Service bulletins are all caps. Sorry.

…NORTHEAST STATES/NEW ENGLAND…
EASTERN CANADIAN UPPER TROUGH WILL DIG SOUTHEASTWARD OVER QUEBEC/EASTERN ONTARIO TOWARD NEW ENGLAND/NORTHEAST STATES THROUGH TONIGHT…WITH ASSOCIATED COOLING/STRENGTHENING CYCLONIC FLOW ALOFT AS FAR SOUTH AS THE MID-ATLANTIC STATES. WITH RELATIVELY STEEP LAPSE RATES/SUFFICIENT CAPE BY AFTERNOON…MULTIPLE SOUTHEASTWARD-MOVING BANDS OF STRONG/SEVERE TSTMS SHOULD DEVELOP/INCREASE THIS AFTERNOON…WITH SUCH DEVELOPMENT FOCUSED IN VICINITY OF A SURFACE TROUGH ACROSS NEW ENGLAND/NEAR THE EASTERN SEABOARD AND/OR ALONG ONE OR MORE SOUTHEASTWARD MOVING WEAK COLD FRONTS ACROSS THE NORTHEAST/NEW ENGLAND. SUSTAINED MULTICELLS ALONG WITH A FEW SUPERCELLS CAN BE EXPECTED…WITH DAMAGING WINDS/SEVERE HAIL AS THE PRIMARY HAZARDS.

“Southeastward moving.” That’s the scare line for me. Our strongest storms move northwest to southeast. In the Plains the strongest storms head to the northeast.

SPC also says the biggest risks are strong winds and large hail. Tornadoes seem unlikely, though you can have comparable damage from microbursts.

The Rapid Refresh model which did well on timing this past Friday shows the system entering Connecticut early afternoon. It will build as it heads in our direction. The computer readout resembles a snowball which grows as it rolls downhill.

This isn’t the last time I’ll look at maps before going to work today.

I’m Sitting And Watching

On nights like tonight I’m more like a life guard than anything else–even the high chair!

Watcha’ doing? Me, I’m sitting.

I’m on a ‘bar height’ office chair in the Weather Center looking at the radar. My own desk on the other side of the room has been unused today. There’s a Severe Thunderstorm Warning for Litchfield County (a marginal call when issued) which will certainly be allowed to expire in six minutes.

On nights like tonight I’m more like a life guard than anything else–even the high chair! I’m just sitting, gazing out at the action hoping nothing happens, but prepared just in case something does.

I’m answering to three separate news outlets: FoxCT, CTNow.com and the Hartford Courant. Each operates separately, but shares some resources (like me). It keeps me on my toes.

I just walked back to Master Control to let them know the “crawl” will disappear at 5:45 PM. I don’t have the number or I would have called. That’s something I need to learn.

I don’t know numbers. I don’t always know names. I am just learning procedures or in some cases helping to formulate them.

The storms are weakening. That’s good.

Tornado Prediction From The Experts

Like a hot air balloon as long as the parcels remain warmer than their surroundings they’ll continue to rise. As described by SPC the Midwest has an added feature this weekend–the jet!

There’s a big severe weather outbreak still underway this weekend. At least one Iowa town was flattened yesterday with 31 tornadoes reported overall. Today it’s ‘only’ six. The evening is young. Three Four tornado watches and one severe thunderstorm watch are up as I type.

The prevailing wisdom is tornadoes form during a clash between warm moist and cool dry air. That’s a situation likely to exist in the Midwest every spring.

However, if you listen to the experts from the Storm Prediction Center you’ll see there’s more. Tech stuff first. I’ll translate after you read it.

SCATTERED VIGOROUS STORMS ARE ONGOING…FROM NEAR THE DEEP SURFACE CYCLONE CENTER MIGRATING ACROSS NORTHWEST WISCONSIN…SOUTHWARD TO THE VICINITY OF A 90 KT SOUTHWESTERLY 500 MB JET AXIS ACROSS SOUTHWEST WISCONSIN. AN EMBEDDED SPEED MAXIMUM IS IN THE PROCESS OF NOSING ACROSS THE UPPER MISSISSIPPI VALLEY TOWARD THE UPPER GREAT LAKES REGION…WITH A REGION OF ENHANCED UPPER DIVERGENCE CONTRIBUTING TO CONVECTIVE DEVELOPMENT.

  • Deep surface cyclone is a low pressure system at ground level.
  • 90 kt southwesterly 500mb jet axis means there’s a wind blowing between 110-115 mph at approximately 18,000 feet. The exact height isn’t important.
  • Enhanced upper divergence means as the wind is moving by it’s spreading out.
  • Convective development means thunderstorms born of air moving upward in the atmosphere

These conditions paint a serious situation because of how thunderstorms form and what make them strong (sometimes strong enough to spawn tornadoes).

In a thunderstorm parcels of relatively warm air rise into a colder atmosphere. Like a hot air balloon as long as the parcels remain warmer than their surroundings they’ll continue to rise. As described by SPC the Midwest has an added feature this weekend–the jet!

A strong jet streak will help rising air ascend even faster and make the situation much more volatile. Divergence means additional air will need to be sucked up from below to fill an increasingly large atmospheric void. It’s a scary and vicious cycle.

The good news is this severe weather is exceptionally well forecast. It’s tough to believe anyone in the bullseye doesn’t know what’s going on.

The bad news is sometimes there’s just nowhere to hide.

Leave No Storm Unhyped

I’m not trying to split hairs here, but Doppler functions from the Weather Service Upton, NY radar can’t get close to the ground in Brooklyn/Queens/Staten Island!

Any time I want to get upset I take a look at Drudge. No disappointment today!

“109 mph Winds Rip Through NYC…”

I hadn’t heard that number so I clicked the link and ended up on AccuWeather‘s site. Their headline reads:

“109 mph Winds Rip Through NYC. NWS Investigating Possible Tornado”

The story by AccuWeather meteorologist Meghan Evans was factual and straight to the point until she said,

Radar indicates that winds topping 109 mph tore through parts of the city.

Oh. Sorry Meghan, that doesn’t count!

I’m not trying to split hairs here, but Doppler functions from the Weather Service Upton, NY radar can’t get close to the ground in Brooklyn/Queens/Staten Island! The NEXRAD radar scans at many different elevation angles. Even the very lowest (.5&#176) is a few thousand feet up by the time it makes the approximately 60 mile trek across Long Island.

Low level winds are effected by friction with objects on the ground. At a few thousand feet that effect is greatly diminished. What the radar shows is often different than what’s happening on the ground.

I’m not saying there wasn’t a 109 mph wind yesterday on the streets of New York City. However, if that wind was there it wouldn’t be seen on NEXRAD!

There’s no doubt yesterday’s weather in New York City was scary and damaging. Is it necessary to quantify it in this less than scientifically sound way?

Why No Watch?

A watch is supposed to be the ‘heads up’ before bad weather strikes.

See note at the bottom of this entry for additional information received since I first posted.

I am surprised there was no severe weather watch for New York City, Connecticut or the surrounding environs this afternoon. Without a watch Staten Island, Brooklyn and Queens went directly to a Tornado Warning just as parts of Connecticut have just gone to a Severe Thunderstorm Warning (since cancelled).

A watch is supposed to be the ‘heads up’ before bad weather strikes.

A Severe Thunderstorm Watch will be issued when conditions are favorable for development of severe thunderstorms. While not anticipated, tornadoes may occur in the watch area. The Storms Prediction Center (SPC) is the sole agency responsible for issuing a watch. A watch covers several thousands of square miles and generally lasts from two to six hours.

I’m not sure yet if there’s been anything more than heavy rain so far in Connecticut but photos and video from New York City show lots of damage. The photo at the top of this entry is unverified so take it with a grain of salt, but it’s a powerful image. (I now have additional info on the photo. See below.)

Everyone expected strong storms. You didn’t have to be a forecasting genius to see that. That makes the absence of a watch even more troubling.

Sometimes I’m just as puzzled by this stuff as you.

Note: After posting this Huffington Post found the image is true but not from Thursday. There was a great deal of damage in Queens and Brooklyn Thursday, but so far no official confirmation of a tornado. I suspect evidence will prove there was one.