Thursday, May 16, 2013

Triple-Digit Temperatures Crush Northern Plains/Midwest Heat Records;
All-Time May Record at Sioux City


Image (click to enlarge): U.S. daily high temperatures for May 14, 2013, from Unisys

While Mid Atlantic residents were complaining about the unseasonable cold temperatures on Tuesday, heat records were being crushed in the Northern Plains and upper Midwest. As shown in the table below, triple-digit readings smashed long-standing May 14 daily records, with a margin as much as 7° at Norfolk, Nebraska. At Sioux City, Iowa, the 106° high also broke the all-time May maximum temperature record. Sioux City climate records date back to 1889. At both Omaha and Lincoln, Nebraska, it was the earliest 100° temperature on record, surpassing the previous records of 5/29/1934 and 5/24/1967, respectively.

Location Record Previous Date Earliest 100
IA CEDAR RAPIDS 94 93 5/14/1932
MASON CITY 99 92 5/14/1998
WATERLOO 96 94 5/14/1932
DES MOINES 94 93 5/14/1988
MN ALEXANDRIA 93 92 5/14/2001
MANKATO 100 94 5/14/1954
MINNEAPOLIS/ST PAUL 98 95 5/14/1932
ST CLOUD 95 93 5/14/1932
ROCHESTER 97 94 5/14/2007
NE OMAHA 101 96 5/14/1915 5/29/1934
NORFOLK 103 96 5/14/1941
LINCOLN 100 96 5/14/1915 5/24/1967
NORTH PLATTE 97 95 5/14/1948
SD MITCHELL 93 92 5/14/1932

The map below, from NOAA/ESRL, shows the temperature departures from average (°C) for the U.S. It shows that nearly all of the country was at least 2°C above or below average, but the positive departures significantly outweighed the negative, both in area and magnitude.



The temperature extremes were a reflection of a strongly anomalous circulation pattern shown in the map below. A very strong ridge of high pressure extended from the eastern Pacific to the Great Lakes at the 500 mb level (near the middle of the atmosphere), while a deep low pressure area was located off the Mid Atlantic coast.



The National Weather Service report for the record at Sioux City:
AT 135 PM THE TEMPERATURE REACHED 106 DEGREES AT THE SIOUX CITY
GATEWAY AIRPORT ESTABLISHING A NEW RECORD DAILY MAXIMUM TEMPERATURE
FOR THIS DATE AND A NEW RECORD FOR THE HIGHEST TEMPERATURE FOR THE
MONTH OF MAY.

THE PREVIOUS RECORD DAILY MAXIMUM TEMPERATURE WAS 97 DEGREES SET IN
2001 AND THE PREVIOUS RECORD MONTHLY MAXIMUM TEMPERATURE FOR MAY WAS
105 DEGREES SET ON MAY 30, 1934. 

THE TOP TEN HIGHEST TEMPERATURES FOR MONTH OF MAY FROM 1889 TO 2013

      DEGREES         DATE  
 1.    105          5/30/1934
 2.    103          5/29/1934
 3.    102          5/25/1967
 4.    102          5/31/1934
 5.    101          5/15/2001
 6.    100          5/06/1934
 7.     99          5/19/1934
 8.     99          5/18/1934
 9.     98          5/28/2006
10.     98          5/24/1939 

Seasonal Outlook

Latest seasonal forecast: Click here.


Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.