Strong NE winds developed Thursday and Friday which piled up water in the western basin of Lake Erie. Video above is from Kelley's Island Friday courtesy Todd Neu.
Wave heights reached 10-15 feet before they settled down Saturday and SundayNortheast Ohio weather and science blog covering severe storms, long term outlooks, climate, behavioral meteorology, technology and other observations
Strong NE winds developed Thursday and Friday which piled up water in the western basin of Lake Erie. Video above is from Kelley's Island Friday courtesy Todd Neu.
Wave heights reached 10-15 feet before they settled down Saturday and SundaySeven Hills, April 20, 2021 |
Here's what most of us said on April 10th: "Winter is over. Spring is here!"
Then the bottom fell out.
Late April/early May cold was significant across the northern half of the US. Slushy snow fell (which melted off fast) on May 9 along with 2-4" of rain Mother's Day. Temperatures for most days were running well degrees below normal from April 15th through last week.
So what happened?
The MJO (Madden Julian Oscillation) headed into a high amplitude phase 7,8,1
This connects well to colder than normal temperatures across the eastern US.
You can see how the surface temperatures & 500mb (upper level pressure pattern) vs normal evolved over the period. I circled the Greenland High Pressure/Block. This was responsible for locking in the pattern set up by the MJO.
April 24-30 temperatures vs normal |
Upper Level Pressure Pattern vs normal |
May 1-9 temperatures vs normal |
Upper Level Pattern vs Normal |
May 10-14 Temperatures vs Normal |
Upper Level Pattern vs Normal |
Here's what the general public was say on May 9-10th: "What is going on here? Snow in May. Seriously? I can't remember the last time this happened this late."
In reality, we had a COLDER early May last year (2020) with even later snowfall.
In late April we started to see signs of warmth the last 2 weeks of May.
This WARMER pattern is a harbinger of what is to come this summer!
I can hear the cries of viewers saying "The weather is going from winter to summer again".
(In reality this has happened many times before in weather history but I digress). Our spatial and recency bias is strong when it comes to weather.
First the April pattern recap:
High pressure was dominant over the northern Pacific and the north Atlantic. This drove temperatures well above normal during the first half of April. We had snow on April 1 in northern Ohio. 6-7 days late we reached 80 degrees!
"The new version of the MEI (MEI.v2) has been created that uses 5 variables (sea level pressure (SLP), sea surface temperature (SST), surface zonal winds (U), surface meridional winds (V), and Outgoing Longwave Radiation (OLR)) to produce a time series of ENSO conditions from 1979 to present"
The evolution of La Nina in years which are similar to the current event's development.
2018 |
2012 |
1999 |
1996 |
What are we expecting this summer?
Based on top analogs looking at past La Nina summers along with other variables, we expect an above number of 90 degree days this summer especially in late July and August. A few 90s are highly possible into early September.
The ground moisture is running slightly below normal as of this writing (May 4). For comparison, last year we were running a rain surplus.
* Wet ground/above normal rainfall in May/early June will limit the expansion of heat and ease of reaching 90 degrees for multiple days. Drier ground over multiple states will enhance ridges of heat in summer making 90+ easier to attain deep into summer.
What are we watching?
* The position and strength of the Sonoran Ridge (high pressure) and the Bermuda high will dictate the position of the summer storm systems.
* Our analysis shows that these ridges especially the Bermuda High will develop by mid June and pulsate north frequently. The relaxation of the ridge periodically (flattening along the northern periphery) will allow storms to drift over the ridge and into the Ohio Valley especially in late June and July.
* We expect a more active July with storms.