The month of July 2016 was warmer and drier than normal. The thirty-day outlook had called for below normal temperatures and above normal precipitation. When revised on June 30, it called for above normal temperatures and near normal precipitation. Compared with July 2015, the month was 0.4 deg. Warmer. No rain fell in July 2015. Year-to-date rainfall was 13.62 inches less through July 31st in 2016 than in 2015. In fact, rainfall thus far in 2016 is slightly below normal.
The month began with the upper air high pressure ridge controlling the region's weather. This resulted in very warm and humid conditions, and a heat advisory through the 4th. The ridge center shifted westward on the 3rd, returning on the 5th, going back westward on the 9th, and building back eastward on the 11th.
While the ridge's influence was weaker, upper air disturbances crossed on the 4th and 10th. This resulted in scattered showers on both days. The haze, present in the region on the 12th, was Saharan dust blown across the Atlantic from Africa. The ridge remained in place after the 11th. Weaknesses between the 18th and 20th permitted a few isolated late-day showers with minimal areal coverage most of which was to the south and east of Tyler.
Moderate relative humidities required a heat advisory. Initially, it covered only the counties along the Louisiana border on the 18th and 19th, but was extended westward on the 20th through the 24th to cover Tyler. The temperature reached or exceeded 100 degrees from the 21st through the 23rd. Two upper air lows crossed the area beginning the night of the 23rd. The first came southward out of the Northern Branch, and crossed on the 25th with showers and thunderstorms from the evening of the 23rd through the 25th. The second, a TUTT (Tropical Upper Tropospheric Trough) low, crossed very slowly from the 26th through the 29th. This brought scattered thunderstorms on each of those days.
Temperatures were slightly lower between the 25th and 29th as a result of these upper air features along with the westward re-centering of the upper air ridge. The upper air ridge returned on the 30th, warming temperatures. There were a few thunderstorms on its flank from Red River into Northwest Louisiana on both the 30th and 31st.
The reporting period for temperatures and phenomenon on each day is for the twenty-four hours ending at midnight hours GMT--6 p.m. CST and 7 p.m. CDT. The reporting period for precipitation is for the twenty-four hours ending at noon GMT--6 a.m. CST and 7 a.m. CDT. All times are given using the twenty-four hour clock, and are expressed in Greenwich Mean Time.
Observations are from NWS Station 41/9207/4 in Tyler, Texas. The term "normal" refers to averages from the standard climatic period 1971-2000.
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July 2016, RECORDS AND SUMMARY: