NATIONAL WEATHER SUMMARY

 

JULY 2017

 

July 2-8: Record-breaking heat arrived across the drought-ravaged northern Plains, boosting weekly temperatures at least 5 to 10F above normal.  The early-July heat hastened winter wheat maturation and further increased stress on rangeland, pastures, livestock, and spring-sown crops.  Temperatures peaked across the northern Plains on July 5, topping 100F in many locations.  Very hot, mostly dry weather also prevailed in the West, maintaining heavy irrigation demands and hampering wildfire containment efforts.  By July 10, more than five dozen wildfires were active across the West.  Except along the Pacific Coast, weekly temperatures generally averaged 5 to 10F above normal.  Hot weather also affected the middle and southern Atlantic States and the western Gulf Coast region, but near-normal temperatures covered much of the southern Plains, mid-South, and Midwest. 

Pre-monsoon heat in the Southwest intensified as the week progressed.  Salt Lake City, UT, posted a daily-record high of 105F on July 5, followed by consecutive records of 103 and 104F, respectively, on July 7-8.  Highs exceeded the 100-degree mark in Salt Lake City on 6 days in a row, from July 4-9.  From July 5-7, Winslow, AZ, tallied a trio of daily-record highs (104, 105, and 104F).  Similarly, Kingman, AZ, registered three consecutive daily-record highs (108, 112, and 108F) from July 6-8.  Periodically, heat extended to the northern Plains and the remainder of the West.  In drought-stricken North Dakota, triple-digit, daily-record highs included 100F (on July 3) in Williston and 102F (on July 4) in Bismarck.  Rapid City, SD, logged a daily-record high of 105F on July 5.  Another wave of heat at week’s end resulted in daily-record highs for July 8 in Montana locations such as Helena (102F) and Missoula (101F).  Scattered daily-record highs were also reported in the Southeast, where Alma, GA, posted a daily-record high of 99F on July 5.  Meanwhile, Western heat generally peaked on July 7 with daily-record highs in California soaring to 127F in Death Valley; 122F in Palm Springs; and 121F in Thermal.  Locations such as Las Vegas, NV (116 and 113F), and Woodland Hills, CA (110 and 112F) closed the week with consecutive daily-record highs on July 7-8.  Farther north, Yakima, WA, collected consecutive daily-record highs (103F both days) on July 6-7.   

 

9-15: The northern Plains faced further deterioration of crop and pasture conditions, as only widely scattered showers accompanied periods of extreme heat.  The week’s hottest weather, relative to normal, gripped the drought-stricken northern High Plains, where temperatures frequently topped 100F and averaged as much as 10F above normal.  Hot weather (temperatures at least 5F above normal) also extended southward through the nation’s mid-section and across most of the western U.S., although a few areas—notably, the central Plains and the Four Corners States—received beneficial moisture in the form of locally heavy showers. Early in the week, intense heat covered the north-central U.S.  In Nebraska, record-setting highs for July 9 soared to 10F in Valentine and 107F in Chadron.  For Valentine, it was the highest reading since July 23, 2012.  Meanwhile in Montana, daily-record highs on the 9th included 99F in Great Falls and 97F in Lewistown.  Following a brief break, heat returned toward week’s end across northern Plains, where Dickinson, ND, posted a daily-record high of 104F on July 14.  Late-week heat was not just confined to the northern Plains, as McAllen, TX, also logged a daily-record high of 104F on July 14.  Farther east, a spell of record-setting heat in the Mid-Atlantic States resulted in a daily record-tying high (98F on July 12) in Richmond, VA.  Late in the week, expansive heat developed throughout the West, leading to daily record highs for July 15 in locations such as Las Vegas, NV (114F), and Lewistown, MT (98F).  

16-22: A broad ridge of high pressure over the continental U.S. resulted in above-normal temperatures nearly nationwide, with cool conditions limited to the upper Great Lakes region and the Pacific Northwest.  In addition, clouds and rain showers helped to slightly suppress temperatures across parts of the Deep South.  Weekly temperatures averaged at least 5F across large sections of the country, stretching from the Great Basin to the Plains and middle Mississippi Valley.  Another area of heat covered the middle and northern Atlantic States.  Some of the hottest weather, relative to normal, blanketed the central Plains, where temperatures locally topped 110F. Farther south, however, hot, mostly dry weather dominated areas from the central and southern Plains to the mid-South, increasing stress on rain fed summer crops.  Meanwhile, widespread showers across the lower Southeast and the Four Corners States contrasted with dry weather in California and the Northwest.  Temperatures across the Plains were impressive, although only a few daily-record highs were broken due to fierce competition from historic heat waves.  With a high of 112F on July 19, Valentine, NE, registered its third-highest temperature on record.  Valentine’s only higher readings were 114F on July 2, 1990, and 113F on July 16, 2006.  The last time Valentine had attained the 110-degree mark was July 21, 2012.  On July 20, Sheridan, WY, posted a daily-record high of 102F.  In Kansas, Salina (110 and 111F) and Russell (107 and 106F) collected consecutive daily-record highs on July 21-22.  Elsewhere, daily record highs included 107F (on July 21) in McCook, NE, and 108 F (on July 22) in St. Louis, MO.  A high of 108F last occurred in St. Louis on July 25, 2012.  At times, heat affected other parts of the country, with daily-record highs climbing to 101°F (on July 17) in Sisseton, SD, and 100F (on July 16) in Tonopah, NV.  In contrast, pockets of cooler air across the North led to daily-record lows in locations such as Meacham, OR (35F on July 21), and Marquette, MI (40F on July 17).

 

23-29: Weekly temperatures averaged as much as 5°F above normal in many locations from the Pacific Coast to the Plains, except in areas that were cooled by clouds and showers associated with the monsoon circulation.  Meanwhile, cool air settled across the Midwest and Northeast—eventually reaching most areas from the Mississippi Valley eastward.  Autumn-like conditions cloaked New England, where weekly temperatures averaged at least 5°F below normal. In the Northeast, periods of cool weather led to several daily-record lows.  On July 23-24 in Maine, both Houlton (38 and 40°F) and Caribou (42 and 45F) posted consecutive daily-record lows.  Houlton reported another record (41\°F) on July 29.  The late-week cool spell, which followed a round of heavy rain in parts of the Northeast, also resulted in consecutive daily-record lows (54 and 50F, respectively) on July 29-30 in Bluefield, WV.  In contrast, record-setting heat affected parts of the South and West, especially late in the week.  In Montana, Townsend registered a daily recordtying high of 97F on July 23.  Later, Texas locations such as Austin (106 and 105°F) and San Antonio (104 and 105°F) collected consecutive daily-record highs on July 29-30.  On the 29th, Austin’s high of 106F tied a monthly record that had been set on July 16, 1978, and earlier dates.  Elsewhere in Texas, McAllen tallied a trio of daily-record highs (104, 105, and 106°F) from July 28-30.  Late-week heat also affected Florida, where Vero Beach closed the week with consecutive daily-record highs of 97F on July 28-29.

Jim G. Munley, jr.
http://www.jimmunleywx.com