March in the U.S.: Crazy Mild, Inconsistently Wet

After the mildest winter in U.S. history, March kept the theme going. Last month ended up as the 4th warmest March in records going back to 1895, according to the monthly analysis released on Wednesday by NOAA’s National Centers for Environmental Information. The warmth was much more consistent than usual for a strong El Niño year (see Figure 3), and more extensive than had been projected in February’s outlook for March. All 48 contiguous states (plus Alaska) were substantially milder than average. Every state from the Northern and Central Plains east to New York notched a top-ten warmest March (Figure 1), although only Alaska (not shown) had its warmest March on record. The nation’s most impressive burst of early-spring warmth arrived in Alaska on the last day of the month, when southeastern parts of the state basked in summerlike readings. A high of 71°F on March 31 at Klawock set a state record for March.


Figure 1. State-by-state temperature rankings for March 2016. Image credit: NOAA/NCEI.


Figure 2. State-by-state precipitation rankings for March 2016. Image credit: NOAA/NCEI.

Precipitation: big winners, big losers
For the nation as a whole, it was a reasonably moist month overall--the 26th wettest March on record for the 48 contiguous states--but the precipitation map itself is a checkerboard of anomalies (Figure 2). The most striking was in the Southwest: New Mexico had its driest March on record (the statewide average was just 0.06”), while its next-door neighbor, Texas, had its 12th wettest March (2.85”). This juxtaposition is a bit artificial, because most of the heavy rains in Texas were focused in the state’s eastern reaches, next to Louisiana (2nd wettest March on record) and Arkansas (3nd wettest). Likewise, although California had its 24th wettest March, most of that liquid gold fell in the northern and central parts of the state, with precious little in Southern California.

Some of the other impressively wet and dry states included Wisconsin (2nd wettest), Mississippi and Michigan (4th wettest), Washington (8th wettest), Virginia (7th driest), New Jersey and Arizona (9th driest), and Pennsylvania (10th driest).



Figure 3. March departures from average temperature (left) and precipitation (right) following the strongest El Niño events in the NOAA record, dating back to 1950: March 1958, 1966, 1973, 1983, and 1988. Image credit: NOAA/ESRL/PSD.


Drenched and parched: our pick locations for March
When it comes to dryness last month, it’s hard to top Arizona. Both Phoenix and Yuma failed to record a single drop of measurable rain--not even a trace. Phoenix’s last measurable rain was on January 31, although the city is a long way from toppling its record-long dry stretch (160 days, set in 1972).

Meanwhile, Memphis, TN, racked up 16.20” for the month. This smashes the previous March record of 13.04” from the region’s devastating spring of 1927, which brought the worst river flood in our nation’s history. Memphis records go back to 1872. Little Rock, AR, also got its wettest March by far since records began in 1875, with 12.33” this month beating out 10.43” (1897). And the 12.83” in Shreveport, LA, beat out 11.99” from March 1945, in records going all the way back to 1871. One of the hardest-hit areas was the Sabine River, which separates Louisiana and Texas. A record flood crest of 33.24 feet at Deweyville, TX--beating a record set in 1884--inundated the town of about 1200 residents for days. Deweyville schools have now been closed for several weeks, as the school system finds itself facing more than $10 million in uninsured losses.

Bob Henson


Figure 4. Homes in Deweyville, TX, are surrounded by floodwaters from the nearby Sabine River on March 15, 2016.