Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 2:37 PM GMT on April 24, 2012
An unprecedented April heat wave brought a second day of sizzling temperatures to the Western U.S. yesterday, where temperatures ranging 20 - 30 degrees above normal have toppled numerous all-time April heat records. Nearly every weather station in the Inter-mountain West has broken, tied, or come within 1 - 2 °F of their all-time record April heat record since Sunday. Most notably, the 113°F measured at Furnace Creek in Death Valley, California on Sunday, April 22 was tied for the hottest April temperature ever recorded in the U.S. According to wunderground weather historian Christopher C. Burt, the hottest reliable April temperature ever measured in the U.S. was 113°F in Parker, Arizona in 1898. A 113°F reading was also taken at Catarina, Texas in April 1984, and at Greenland Ranch in Death Valley on April 24, 1946. A hotter 118°F reading measured at Volcano Springs, CA in April 1898 is considered unreliable, since we don't know much about the exposure conditions or if the thermometers were even in shelters at remote California desert stations back in the 1880s and 1890s. The previous hottest April day in Death Valley was 111°F. Yesterday, the high temperature in Death Valley "cooled off" to 110°F, merely the fourth highest April temperature ever measured there. The heat wave peaked Sunday and Monday, and temperatures will be closer to normal for the remainder of the week.
Figure 1. All-time heat records for the month of April were set at 56 stations April 21 - 23, including at seven major cities. Image taken from wunderground's new extremes page.
As is often the case when a major Nor'easter is affecting the Eastern U.S., the record-breaking heat is due to a contortion of the jet stream that has created a strong ridge of high pressure over the Western U.S. Wunderground's extremes page lists 56 stations in the West in the past four days that have tied or broken all-time heat records for the month of April, including:
Phoenix, Arizona: 105°F (previous 105° April temperatures occurred on 4/20/1989 and 4/29/1992)
Las Vegas, Nevada: 99°F (tying old record set 4/30/1981)
Reno, NV: 90° (old record 89° 4/30/1981)
Elko, NV: 87° (old record 86° 4/30/1981). This also beat the previous so-warm-so-early-in-the-season record by 4°
Ely, NV: 84° (old record 82° 4/28/1992)
Winnemucca, NV: 90° (tying old record set 4/30/1981)
Grand Junction, CO: 89° (tying all-time April record also set on 4/29 and 4/30, 1992)
Boise, ID (91°) and Salt Lake City (88°) both came within 1°F of their record April max.
Figure 2. A late-season Nor'easter on April 23, 2012 leaves heavy snow on a farm in Penfield, NY. Image credit: wunderphotographer tvsportsguy.
Late-season Nor'easter winding down
The powerful late-season Nor'easter that brought snow, high winds, and heavy rains to the Northeast yesterday is winding down as it moves northwestwards into Canada. The storm brought an unusual amount of snow for so late in the season to western Pennsylvania, western New York, and the higher elevations in West Virginia. An earlier report posted by the NWS of 23.7” at Laurel Summit, Pennsylvania (elevation 2,770’) has now been scaled back to just 13.7”, according to the latest NWS Storm Summary. Many other higher-elevation locations saw snowfall amounts in the 6 - 12 inch range. Snow amounts were considerably lower in the major cities of the region; Buffalo, New York got 0.9", Rochester, New York, 2.8", and Erie, Pennsylvania, 0.5". The wet, heavy snow fell on regions where trees had already come into leaf, thanks to the surprise "Summer in March" heat wave that brought 80° temperatures to the Northeast over a month ago. High winds that accompanied the heavy snow caused extensive tree damage and power outages to at least 75,000 people in the region. However, the storm may have done more good than harm--widespread rainfall amounts of 2 - 4 inches occurred across Massachusetts, Rhode Island, New Jersey, Connecticut, and Southeast New York, which is under moderate to severe drought. Rainfall deficits in the region were generally 5 - 10 inches, so the Nor'easter's rains will make a significant dent in the drought. Wunderground's weather historian Christopher C. Burt has updated his post on Record Late Season Snowfalls with information from this storm.
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