May/2020 Weather and Climate Recap

This will be my last post recapping May 2020 weather, and I'll take a look at the year's weather so far.

First, here is the average mean temperature for the month of May, observed on a percentile scale. This means that if you see a 100, May 2020 was warmer than 100% of Mays in recorded history and if you se a 1, May 2020 was warmer than 1% of Mays in recorded history.

Average mean temperature percentiles for May 2020 (Northeast Regional Climate Center)

Evidently, it was quite cool in the Mid Atlantic, but as you head further north, things warmed up compared to normal. Here are the values for those average mean temperatures in °F.

Average mean temperatures for May 2020 (Northeast Regional Climate Center)

As far as 2020 goes, the story is much different. Here's the same map as the first one (the percentile one), but for the year to date so far.

Average mean temperature percentiles for 2020 (Northeast Regional Climate Center)

2020 thus far has been in the 80th or 90th percentiles for almost all stations in the Northeast, meaning it surely has been hot when compared to normal! I think this is particularly due to a warm winter that we had, given that April and May were so cold this year. And it looks like that warm trend for the year will continue. Here is the Climate Prediction Center (CPC) three month outlook for temperature, which was released on May 21. The colors indicate probabilities that temperature will be above or below normal, and any red areas are places that the CPC expects to have above average temperatures over the next 3 months.

3 month temperature outlook (CPC)

Put simply, the CPC expects it to be a hot summer, which will likely make us continue to have one of the warmest years on record here in the Northeast.

Enjoy your Sunday!

Cooler Air Incoming

Today will feel quite hot as we'll see temperatures in the mid to upper 80s with high, muggy dew points as well. Here is a look at NAM temperatures for this afternoon. Those areas of red are hot air!

NAM 2-m temperatures for 2 p.m. eastern Saturday (Tropical Tidbits)

That's all to change as a cold front moves through and temperatures begin to drop as we head into the new work week.

Sunday is sort of that transitional day, as temperatures have dipped into the 50s and 40s in spots, a refreshing change from the heat we've been seeing.

NAM 2-m temperatures for 2 a.m. eastern Sunday (Tropical Tidbits)

Notice how different the two NAM maps look, even though they are only 12 hours apart! And by Monday morning we're even cooler, with temperatures having dipped into the 30s in spots.

NAM 2-m temperatures for 5 a.m. eastern Sunday (Tropical Tidbits)

Enjoy the warm (but muggy) weather today, and have a great weekend!

Climate Change

Happy Friday!

I've come across a few graphs and maps over the past few days that show that climate change is truly happening, so I wanted to share them with you all.

First, despite the reduction of travel due to COVID-19, CO2 levels are currently at their highest level in recorded history.

Atmospheric CO2 in Parts Per Million (PPM) (NOAA)

Atmospheric CO2 is now at a new high of just above 417 parts per million (PPM), as shown in the above graph based on data recorded at Mauna Loa Observatory in Hawaii. CO2 levels typically peak in May each year, and what's interesting is that the levels continued to rise this year despite a large-scale reduction of travel because of COVID-19.

The National Weather Service (NWS) uses 30 year climate norms when considering what is "average". So when reporting how far a temperature is compared to average, it will look at a 30 year period of temperatures. Right now, we are still comparing to the period from 1981 to 2010, but that'll change after this calendar year as we begin to compare to climate data from 1991 to 2020.

One of my favorite climatologists, Brian Brettschnieder, created two neat maps to show how these climate normals will change after this calendar year.

Places where climate normals will be warmer or cooler (Brian Brettschnieder)

In the above map, all those places with red dots are places that we can expect climate normals for 1991-2020 to be warmer than 1981-2010, so the only area that will be cooler is central Canada.

Difference between 1991-2020 and 1981-2010 climate normals in °C (Brian Brettschnieder)

This map shows the difference between 1991-2020 and 1981-2010 climate normals in °C, and it is quite clear that Europe has been very hot over the past 10 years (the years that were not included in the 1981-2010 normals). And those places in central Canada that will be cooler in the upcoming new normals will only be slightly cooler than the previous climate normals.

Sadly, this is more evidence that the globe is warming and climate change is happening.

May Review for BDL

This post is a similar one to the May weather review that I posted for BTV, but for Bradley International Airport in Hartford, CT.

May 2020 daily data for BDL (xmACIS) 

The average temperature for the month was 70.5 °F, when the normal mean temperature is 71.2 °F, giving us an average temperature departure of -1.1 °F, so we were slightly cooler than normal. As for precipitation, we saw 20 days with a trace or more of precipitation, though we only saw 1.62 total inches, when normal is 4.35 inches, so it was a rather dry month.

Daily temperature graph for BDL for May 2020 (xmACIS)

The above graph shows temperatures for the month at BDL. Notice that we were quite cold and below the normal temperature range at the start of the month, but we warmed up towards the end of the month.

A highlights for the month include the trace of snowfall that we saw in early May since May is very late to see any snow in CT. We set a new May 11 record minimum temperature, when the temperature dropped to 31 °F. I'd say May 2020 was somewhat abnormal, with cool temperatures and much below normal precipitation for BDL.

I'll post about May and 2020 on a global scale in future posts.

Busy Weather Day Today

Today will be a fairly active weather day throughout the country.

Here is a look at the Storm Prediction Center (SPC) outlook for today with areas in color showing a risk for storms.

SPC 1 day outlook for today (NWS)

The biggest risk is in the New Jersey area, where we have already seen some storms with large hail and damaging winds today (sorry about the later post today). For us in New England, the biggest risk for some afternoon storms will be in southernmost areas like Fairfield County, CT.

GOES-East view at 2 p.m.

The above image shows a NASA GOES-East satellite where the big storm clouds have now moved off the New Jersey coast. We're cloudy here in New England now, but we can expect some convection to pop up in spots this afternoon.

Here is radar showing that storm that was hitting the mid-atlantic states hard earlier today.

Radar at 2:48 p.m. eastern time (NWS)

I don't see us having too much risk for severe storms today, but it'll be something to keep an eye out for as convection can pop up fairly quick.

Cristobal

This post will be a fairly short one.

Hurricane season began yesterday, and with that, we have our 3rd named atlantic hurricane of the year. This one is Cristobal, and it is located near Mexico right now.

Atlantic Tropical Cyclones and Disturbances (NHC)

The National Hurricane Center (NHC) reports that this storm has maximum sustained winds of 40 mph with a maximum central pressure of 1004 mb. Here is some additional information about the storm.

NHC key messages (NHC)

If the storm does impact the U.S., it would do so this weekend, so this one will be one to keep an eye out for in what has been a very active season in the tropics thus far.

BTV May Recap

Today, June 1st, marks the first day of meteorological summer and the first day of the Atlantic Hurricane Season. With that, I wanted to take a look at some weather data for May for Burlington International Airport (BTV).

May 2020 daily data for BTV (xmACIS) 

The average temperature for the month was 57.9 °F, when the normal mean temperature is 56.3 °F, giving us an average temperature departure of 1.6 °F. As for precipitation, we saw 2.61 total inches, when normal is 3.45 inches.

Daily temperature graph for BTV for May 2020 (xmACIS)

The above graph shows temperatures for the month at BTV. Notice that we were quite cold and below the normal temperature range at the start of the month, but we warmed up significantly towards the end of the month and even set a new record high temperature for the month of May in BTV on May 27 at 95 °F.

Some highlights for the month include the snowfall that we saw in early May (given that BTV averages 0 inches of snow for May) and the intense heat at the end of the month. Temperature-wise, we ranged from 32 °F on May 9 to 95 °F on May 27. Overall, I'd call May 2020 a fairly normal month, with temperatures slightly above average and precipitation a little below normal.

I'll have an update on CT weather for May 2020 in a future post.