As promised I am starting a summer heat diary for the United States, which will be more technical, meteorologically, than most of my prior posts. Questions from laymen not knowing much about meteorology are most welcome since the jargon used here will be geared more towards my associates with degrees in weather science. My intent is to show how any dangerous heat waves are developing on a weekly basis, and I will definitely communicate how intense the heat gets across some sections of the nation. At times, there will be cool enough conditions to produce record lows, as well, which I will also delve into. Due to carbon pollution the chances of having a hot summer, overall, are much higher this year and all years in the foreseeable future.
Even before June, Miami, FL tied its all-time record of 98 on May 28th. Florida has been surrounded by above average sea surface temperatures during the spring helping to strengthen a warm ridge aloft over that state leading to above average temperatures:
So what does the 500 millibar pattern look like at the start of June?
As a meteorologist this 500 Mb chart looks fairly innocuous showing a weak low, or storm system moving through Texas and the South, near average conditions in the Pacific Northwest and East, and a warm to hot ridge stretching from the Southwest northward into the Dakotas. There have been over fifty reports of daily record temperatures in association with the warmth that built ahead of the system noted over the Pacific Northwest just in the first two days of June catalogued by the NCEI records site: https://www.ncdc.noaa.gov/cdo-web/datatools/records
Here is an update of my “colored records genome” through 6/2/17:
Most of those 54 reports from 6/1-6/2 come from Montana and North Dakota. For example, it got up to 96 in Brandenberg, MT on the 1st. Brandenberg’s old record was 93 set in 1956. The heat that built into the northern Plains was quickly moderated by the frontal system moving out of the Pacific Northwest as noted by the dip in the jet over the northern Rockies on the Pivotal Weather chart. The heat was brief enough not to be life threatening unless people did not heed sensible safety precautions, such as keeping windows slightly rolled down in parked cars so that those vehicles would not become ovens.
Another method I like to use to hone in on any extreme heat or cold is the 500 Mb anomaly chart. The one shown here for 6/3 at 00z shows that the warmest anomalous conditions had moved from Montana and North Dakota into northern Minnesota:
Perhaps the best clue for forecasting record temperatures is the 850 Mb chart. Here we see that it was +22-27C at 850 Mb in North Dakota the evening of the 2nd, which would easily send temperatures above 90F at the surface (near record maxes for this time of the year):
Any prolonged heat this summer will also exacerbate polluted air. Today Jeff Masters and Bob Henson published a good report on expected heat and air quality here: https://www.wunderground.com/cat6/summer-us-forecast-hotter-more-polluted-usual
So will we see any notable hot weather by this weekend across the nation? Model ensembles are forecasting the following weather pattern across the continental U.S. for the 8th (imagery courtesy Penn State):
Except for Montana and the northern Plains again, the answer is no through Friday the 8th. Cool, unsettled conditions will persist in the mid-Atlantic where we might see a few record cool reports in association with an upper low. The Pacific Northwest will also get cooler due to a strong upper low moving east and south from the Gulf of Alaska. Our ridge in the Southwest will be hot, but not noteworthy.
Here are the association 850 Mb temps:
Again, another system moving into the Pacific Northwest should funnel temperatures conducive to record warmth northward into Montana on the 8th. I have found over the past 30 years of my career that weather patterns repeat often during the summer.
I may add onto this post through the 8th should I get more noteworthy information. Dear diary, for now, the bottom line is that no widespread areas of near record heat in the U.S. will occur during the first week of June.
To see all 2017 Heat Diary entries click:
https://guyonclimate.com/category/heatdiary2017/
The Climate Guy