7:00 AM | *US drought - about as low as it gets*

Current US Drought Monitor map with only 1.58 percent of the nation experiencing D2 (severe), D3 (extreme) or D4 (exceptional) drought conditions; courtesy NOAA and National Drought Mitigation Center (NDMC) at University of Nebraska-Lincoln

Overview
It is not often that “severe”, “extreme” or “exceptional” drought conditions are limited to only 1.58 percent of the continental US, but that is exactly what we have right now across the country. We know that these good times will not last for too much longer; nonetheless, it is worth noting that this is about as good as it gets for the US regarding drought.  In fact, going back to the year 2000, only the early part of 2010 featured somewhat similar limited drought conditions on a nationwide basis to what we are enjoying today.  Just under five years ago in August of 2012, the nation was at a real dry point and nearly 25 percent of the country was classified with “extreme” drought.  

Western US drought conditions from one year ago (left) to current (right); courtesy NOAA/CPC

Discussion
In recent years, much of the western US was suffering through widespread and deep drought, but that has changed dramatically in recent months; especially, in the state of California.   One year ago, much of California was in the midst of an “exceptional” drought – the worst category of drought as classified by NOAA/NDMC - but all of that has changed dramatically this winter and spring with a tremendous amount of rainfall throughout the state.  In fact, drought conditions have improved so much in recent weeks, there is no part of California that is currently classified as experiencing “extreme” (D3) or “exceptional” (D4) drought conditions – and amazingly, this holds true for the entire western US. 

Sierra Nevada Mountains provide more than 60% of California's developed water supply

In addition to the recent significant rainfall in California, there has been an extreme amount of snow in the higher elevations of the Sierra Mountains across eastern California.  Snowpack in the Sierra Nevada region plays a critical role in California’s water supply as a natural form of water storage.  In fact, more than 60% of California’s water originates in the Sierra Nevada region.  There has actually been so much snow this winter in some of the higher elevation locations that the National Guard has been called out to help with the removal of the snow.  

NOAA's prediction of 7-day rainfall amounts with significant amounts in the central US and much needed rain across Florida.  Note- every state in the contiguous US receives some rainfall over the next week.

The one area of the country that is currently experiencing some areas with “extreme” drought condition is the Southeast US.  Specifically, the latest drought monitor update shows "extreme" drought conditions across southern Georgia and central Florida, but the near-term looks quite promising with decent rains likely over the next 7 days; especially, in the state of Florida. Quite amazingly, the latest NOAA prediction of rainfall over the next 7 days has rainfall in every single state of the contiguous US.

In the medium and longer term, I believe there is ample reason to be optimistic regarding the "extreme" drought conditions in portions of the Southeast US with the increasing likelihood of a wetter pattern. For one thing, the Atlantic Basin tropical season is just now getting underway and there is warmer-than-normal water throughout the Caribbean Sea.  This anomaly in sea surface temperatures should boost chances for decent tropical system-related rains in the Southeast US during the next few months - alleviating even further the "extreme" drought conditions that currently exist in some sections.  For more on the "2017 Atlantic Basin Tropical Outlook" click here.

The Palmer drought index, sometimes called the Palmer drought severity index and often abbreviated PDSI, is a measurement of dryness based on recent precipitation and temperature. The Palmer Drought Index is based on a supply-and-demand model of soil moisture. Drought conditions were extremely widespread and severe in July 1934 during the midst of the “Dust Bowl” era and much worse than today (most recent measurement April 2017; courtesy NOAA/NCDC 

1930’s – about as bad as it gets in terms of drought (and heat)
Any drought talk of recent years really pales in comparison to what happened in this country during the decade of the 1930’s.  “The Grapes of Wrath” is a book written by John Steinbeck that was published in 1939 and it captured well the plight of millions of Americans whose lives had been crushed by what is referred to as the “Dust Bowl” era.  The 1930’s still ranks as the hottest and driest in US recorded history and the “Dust Bowl” was truly a significant event in our national history. 

The figure on the left shows the annual values of the U.S. Heat Wave Index from 1895 to 2015 for the contiguous 48 states. An index value of 0.2, for example, could mean that 20 percent of the country experienced one heat wave, 10 percent of the country experienced two heat waves, or some other combination of frequency and area resulted in this value.  Data source: Kunkel, 2016 (EPA).  The figure on the right shows the number of all-time maximum temperature records at USHCN weather stations that reached extreme heights in 1936 - far and away above any other year.

Conditions were so dry in such a widespread part of the country that dust storms formed numerous times in the Central Plains as loose soil turned to dust which the prevailing winds blew away in huge clouds that blackened the skies – even as far away as the east coast. The drought came in three waves during this decade, 1934, 1936 and 1939-1940, and tens of thousands of families had to abandon their farms.

Meteorologist Paul Dorian
Vencore, Inc.
vencoreweather.com