NOAA: Updated June 2021 Outlook – West Hotter Than Normal With PNW Also Drier Than Normal

WeatherBrains | | WeatherWeather
June 2021, temperature, NOAA, outlook
June 2021 temperature outlook. Credit: NOAA

The NOAA has just released an updated 30-day outlook for June 2021. Expect warmer than average temperatures in the west, northeast, and across the northern plains and Great Lakes. For precipitation, expect the PNW to be drier than normal, and the southern High Plains to be wetter than normal.

Full text discussion below:

The update to the June 2021 temperature and precipitation outlooks are driven 
primarily by the most recent short-, medium- and extended-range model guidance 
as well as the most recently available subseasonal and monthly integrated 
forecast products. The MJO has become less coherent in recent weeks and does 
not play as much of a role in the updated outlook, while soil moisture 
anomalies continued to inform the June temperature outlook. 
Changes to the June temperature outlook are generally small overall. The 
outlook continues to favor above-normal temperatures in an inverted horseshoe 
pattern encompassing areas from the Southwest CONUS to the Pacific Northwest 
across the northern Plains and Great Lakes to the Northeast and mid-Atlantic. 
Strong ridging anticipated during much of the first half of June increases odds 
for above-normal temperatures for the Northeast, Great Lakes and mid-Atlantic 
compared to the mid-month outlook. Also, highest probabilities for above-normal 
temperatures in the western CONUS have been shifted to the northwest and are 
now focused in the central Great Basin and western Rockies where ridging and 
warmer-than-normal temperatures (some potentially extreme) are likely during 
the first week of June. 
The most substantial change in the updated June outlook, is the inclusion of 
favored below-normal temperatures for the southern Plains, lower Mississippi 
Valley and western Gulf coast. The mid-month outlook did note the uncertainty 
in this region and potential cooler temperatures with a forecast area of 
Equal-Chances (EC) due to negative 500-hPa heights indicative of weakened 
sub-tropical ridging and enhanced cloudiness and precipitation. Model guidance 
through the end of May 2021 across time scales has become more clear and 
increased the likelihood of the conditions described above. Substantial further 
support for this addition is the recent heavy rainfall, especially for parts of 
east Texas and Louisiana, which has maintained or increased anomalously wet 
surface conditions across this region. Some minor changes are made in Alaska in 
the update, but forecast confidence is low and only very slight tilts from 
climatological odds are depicted for the state. 
For precipitation, the updated June 2021 outlook illustrates some minor 
adjustments in general from the mid-month outlook. Favored below-normal 
precipitation remains for the northern Rockies and Pacific Northwest, but has 
been removed from parts of the eastern Southwest and southern High Plains. 
Model guidance favors some rainfall early in the month in this region where 
normal precipitation totals are relatively low. 
In addition to the potential MJO influence noted in the mid-month discussion 
below, model guidance across time scales has increased confidence for 
above-normal precipitation for a region from Texas to the lower Ohio Valley, 
mid-South, Gulf coast, Southeast and lower mid-Atlantic. Greatest odds are for 
parts of eastern Texas and Louisiana. 
Other minor changes include the addition of a small region of favored 
above-normal precipitation for parts of the northern Plains and upper 
Mississippi Valley, but confidence is low. High uncertainty due to varying 
signals in the available forecast tools across time scales in Alaska has led to 
a forecast of EC for the state of Alaska in the updated June outlook.
June 2021, precipitation, NOAA, outlook
June 2021 precipitation outlook. Credit: NOAA

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