Historic Heat and Drought

Originally posted on ZoomRadar

If you could ask people throughout the contiguous United States what two words they would use to describe the weather conditions this spring and so far this summer, I would imagine the answers would run along the lines of hot and dry. This has been the case for most areas in the lower 48 states so far this year, though it is important to note that this is not true for everywhere in the lower 48. In fact, some areas have seen above normal precipitation so far this year, including areas of central Texas, most of Maine, as well as many areas of the Pacific Northwest, northern Rockies, and northern Plains.

The graphic below shows how temperatures compared to the 1981 to 2010 average across the lower 48 last month. Despite the month officially rating as the fourth warmest June on record globally, with records dating back to 1880, some areas of the U.S. saw below normal temperatures during this time period, denoted in blues below.



But like I stated previously, most of the nation has been experiencing heat and little rainfall. June marked the 328th continuous month with temperatures above the 20th century average according to NOAA. The United States seems to be taking the brunt of the heat as well. Temperatures globally in June were nearly two degrees Fahrenheit above average on the world’s landmasses and have been 1.57 degrees above average so far this year. But in the U.S., temperatures have been averaging 4.5 degrees above normal so far this year, now that is some heat!

And as if the heat was not enough to worry about, drought conditions have continued to worsen across a vast portion of the lower 48 states. Drought conditions are depicted in the map below as of July 10th and have likely continued to worse across many portions.

In terms of the area affected by this drought, this is now officially the worse drought since the 1950s. About 61% of the continental U.S. currently qualifies as being in some level of a drought according to the U.S. Drought Monitor. The Palmer Drought Index, an older and less detailed index, reports that 56% of the United States is currently under drought conditions. The last time drought covered more area in the lower 48 states was in December 1956.

This current drought does not compare to past droughts in duration yet, but with no major relief in the near future, conditions may continue for some time. Below is the NAM model depicting how much precipitation may fall over the next 84 hours. While some relief may fall over this time period, it will not affect all areas and will not be enough to eliminate the precipitation deficit, though any help will be very welcomed in these areas.

Below is the precipitation across the United States over the past 60 days when compared to normal, showing many areas suffering from precipitation deficits.

All of this heat and lack of precipitation has unfortunately led to many issues across the nation and will continue to do so. Heat related deaths have occurred in many states and many more have likely suffered from heat related illnesses. Additionally, dry conditions have wreaked havoc on the nation’s corn crop, with the U.S. Department of Agriculture now reporting that 38% of the crop is in poor or very poor condition. Problems have also arisen in the form of wildfires due to the dry conditions. Below is a map showing the current large wildfires across the United States.

The summer will likely continue with more hot and dry conditions so it is important to take precautions to protect your life and property. Be sure to stay hydrated, take breaks from the sun, monitor any fires you start closely, and of course stay up to date on the latest weather information.

Heat Set to Return to the Northeast and Dry Air Takes Hold in the Southwest

Originally posted on ZoomRadar

Below are the forecasts from the Climate Prediction Center for 6 to 10 days out, June 10th – 14th, for the probability of temperatures being above and below average and precipitation being above and below average.

The Climate Prediction Center has also issued a forecast for the same variables for the 8 to 14 day period which would be from June 12th – 18th.

The Northeast

A cold front pushed through the northeast late last week bringing rounds of storms to the area. Behind that, the northeast has been under an air mass providing for seasonable, if not below average, temperatures for the past few days. Temperatures will slowly begin to climb this week and by this weekend above average temperatures will be in store for most again. The Climate Prediction Center forecasts above average temperatures being likely across the northeast from June 10th through the 18th. The 18Z run of the GFS model depicts this early on in the period as shown below.

The top image shows temperatures for the early to mid afternoon on June 11th and the second image shows temperatures for the early to mid afternoon on June 12th. Temperatures may exceed 90 degrees in some areas meaning daytime highs could reach around the 95 mark in some isolated areas. Most areas of the Northeast will see high temperatures at least into the upper 70s to low 80s with most areas being well into the 80s though.

The forecasts diverge somewhat come the second half of the period as the Climate Prediction Center continues to indicate above average temperatures being likely. However, these forecasts are not as likely as they forecasted during the first half of the period. Meanwhile, the 18Z run of the GFS model expects some cooler air to potentially enter parts of the Northeast. Below is the early to mid afternoon temperatures for June 18th. Some temperatures are struggling to reach the 60 degree mark in New York state on this date according to the GFS. Granted this forecast is pretty far out but it may be that the warm temperature returning to the Northeast this week do not last as long as the Climate Prediction Center believes they will.

The Southwest

The Southwest has been suffering from drought conditions for some time now. As of the May 29th update, most of the Southwest has been classified under a severe drought.

In fact, many of these areas across the Southwest have received little, if any, precipitation during the past two weeks.

This, combined with the lack of precipitation expected in the near future, will set the stage for fire weather across this area. The June 10th through 18th period is expected to result in below average precipitation across the Southwest according to the Climate Prediction Center. The 18Z run of the GFS model shown below shows this below average precipitation over this time period.

For this reason, some areas of the Southwest have been highlighted by the Storm Prediction Center as being under a threat for wildfires on June 8th and 9th. This threat for wildfires will undoubtedly continue beyond this time frame as dry air continues to stay in place.

Below is the 18Z GFS model showing very low dewpoints and strong surface winds across the threat area on the 8th and the 9th. In fact some dewpoints may struggle to hit zero degrees showing just how dry the air will be across the desert Southwest.

March Heat!

Originally posted on ZoomRadar

March 2012 was the warmest month ever across the lower 48 states with respect to climate averages in the 33-year satellite temperature record. Below is an image which shows just how warm it was during the month of March.

Areas across the Midwest, Great Lakes, and northern Plains saw temperatures the most above average with temperatures at least 9 degrees Fahrenheit above average across most of this area. In fact, some areas saw temperatures 15 degrees Fahrenheit above average for the month. The weather was so nice, instead of it feeling like March, many areas saw temperatures more typical of the month of April with some weeks feeling like midsummer. All together, 6199 high maximum temperature records were broken and another 1556 high maximum temperature records were tied. This means that a little over 3.5% of all the March United States high maximum temperature records broken! Below is an image depicting the areas where high temperature records were broken or tied, with areas showing more black overlaid on red having a higher concentration of record breaking or tying.

The great amount of broken records just did not apply to high maximum temperatures though, as high minimum temperature records also fell. By the end of the month, 6210 of these records had been broken and another 1307 tied. This meant that once again, just over 3.5% of all March United States high minimum temperature records were broken. Below is an image that depicts the areas where these events occurred.

You may have noticed in the first image showing temperature anomalies for the month of March that not all of the United States saw such warmth this past month. Some areas, mainly along the West Coast, actually saw below average temperatures during the month of March. However, this cold was nowhere near the heat that the rest of the nation experienced as only 603 low maximum temperatures were broken or tied and 287 low minimum temperatures were broken or tied, with the majority of these events occurring on the West Coast.

So what made this month so warm? Above is an image of the 500 mb geopotential height anomalies based on the 1981 to 2010 average for the month of March. As you can see, the eastern portion of the nation saw height anomalies at 500 mb well above average which means a couple of things. First off, it speaks to the trend of the jet stream for much of the month which was well to the north, allowing for warm air to flow in from the south. It was this large high pressure system which helped “block” intrusions of cold air from entering the eastern portions of the US. But also, it shows that areas with larger height anomalies saw generally, the most warming. This is because the warming of air causes it to expand and seeing as it cannot expand into the surface of the Earth, it must expand upward thus causing these height anomalies to exist.

However, global temperatures were not all that far above average with only about a .2 degree Fahrenheit anomaly based on the 30-year climatological average for the month of March. It is important to keep this in mind when making statements for or against the argument of global climate change. The United States is just one portion of the globe and therefore weather extremes that occur here may be totally negated by the opposite extreme in other portions of the world. No one can argue that March was a very warm month for the eastern two-thirds of the United States but blaming particular incidents on climate change is unwise when so little data has been collected in the realm for the entire history of the planet. If this past month taught us anything, it is that our climate can present us with very abnormal weather and it is these patterns that we should continue to monitor closely.