Barry Lynn
Intersection of Science and Policy

Do You Remember Such Crazy Weather?

Do you remember such crazy weather?  A springtime storm in early February?

Plenty of moisture and dust from a recent storm combined with a (typically Springtime) Red Sea Trough to bring us an afternoon of intense storms.  Here in Efrat, the rain literally poured down the windows, as if a giant car wash had come to wash off all the homes.  My rain gauge showed forty five millimeters of rain in just half an hour.  More than 207,000 lightning events were recorded from Egypt to Lebanon, from the eastern Mediterranean to Jordan and Saudi Arabia. About a third of these were cloud to ground lightning, as measured on Earth Networks Global-and the Israel Total Lightning Network.

Although interspersed with dry periods,  this season’s accumulated rainfall has been close to or above normal.  This makes one question the societal and economic value of seasonal forecasts, which predicted that our seasonal rainfall would be much below normal.  True, we’ve had our extended dry and warm spells this winter, but we’ve also had high rainfall events.  Both are consistent with a warming world.

Regardless of our current warm spell, weather forecasters have been taking notice of a potential storm during the mid-month period — that is a return to much wetter and colder weather.  A Sudden Stratospheric Warming that occurred at the end of last year has shaken up the atmospheric circulation, creating ripples in the Jet Stream that continue to today  (https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/wind/sudden-stratospheric-warming#:~:text=Sudden%20stratospheric%20warming%20describes%20an,our%20weather%20at%20the%20surface.).  These ripples have caused the Jet Stream to snake, creating blocking atmospheric patterns.

One such blocking pattern can cause unusually cold air to flow southward from Siberia.  When such cold air interacts with the polar or subtropical Jet Stream it can create conditions for a snowstorm in the Jerusalem mountains

In fact, we do see some signals on the forecast maps for a period of snow during the mid month period.  However, global forecast models have greater difficulty predicting the movement and positioning of atmospheric blocks, and this has led to fluctuations in the forecast.  Right now, we are pretty sure about much colder weather being on the way, but are much less sure of any snow.

Still, I’m giving the heads up because I’ve come into some criticism in the recent past for not meeting expected “standards.”  it started the previous Friday evening when I put on my coat, took my prayer book, and headed out to Minyan.  I was — I admit — a bit surprised to find that it was raining.  True, I knew it might rain, but I wasn’t sure it would rain until I stuck my head and the rest of me out the door.  I returned home just as my wife came downstairs to light the Shabbat candles.  She could only say that the whole episode was a big embarrassment (for her).  She wouldn’t dare to go shopping on Sunday for fear of meeting someone who might have seen her husband out in the rain, searching for a Minyan.

Then, the next day, I learned that I am the cause of marital “strife.”  The husband, I was told, follows my discussion, while the wife follows the weather page (weather-it-is-israel.com).  For cost reasons, the weather page’s forecast is based on a single forecast, while my discussion for several days out is based on an ensemble of global forecasts.  Ensemble forecasts can be made with the same forecast model, but the weather forecast modellers perturb the observed conditions to create multiple forecasts for the next day or days, or weeks.  When the forecasts are quite similar to each other, we have greater confidence in any single forecast. The result can be that a forecast discussion for Shabbat where based on the ensemble forecast  I can speak about the chance of rain, while the website forecast shows just a sunny day.  I suggested to the couple that not everything is black and white, and that each one has to give a little to make things works.

In fact, a little forgetfulness can go a long way.  In fact, I appreciate it when people quickly forget my forecasts when they are not so accurate (e.g., wrong).

At the same time, we have to be careful not to create false memories themselves! For instance, The New York Times report on a hammer attack in Midtown Manhattan revealed how witnesses can embellish their memories to fit a preconceived narrative.  In the reported story, both persons saw parts of the attack, but not all of it. One witness thought the police had shot a fleeing man, while another thought the police shot the same man while he was on the ground in handcuffs. Cameras clearly showed, though, that the man tried to attack another police officer with a hammer, who was then shot in chase, and handcuffed only afterwards. The article suggests that our minds partake in this charade in order to make sense out of quickly changing events, especially in times of stress.

While much of our daily existence is not as exciting as a city chase, we all should keep in mind that while our memories serve us, sometimes our memories are simply the world we wish for.

About the Author
Dr. Barry Lynn has a PhD in Environmental and Atmospheric Sciences. He has an undergraduate degree in Biology. He is a researcher/lecturer at the Hebrew University of Jerusalem, and is the CTO of Weather It Is, LTD, a weather forecasting and consulting company.
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