September 2017 was the second driest September on record. The 0.01 inch of rainfall was greater than the no rain which fell in September 1899, and sharply contrasted with August 2017 the wettest August on record with 11.65 inches. The month was slightly warmer than normal.
The thirty-day outlook for September 2017, issued on August 17, had called for below normal temperatures and near normal precipitation. The August 31 revision changed the outlook to near normal temperatures and below normal precipitation. Compared with September 2016, the month was 2.2 deg. Cooler and 1.32 inches drier. Year-to-date rainfall through the end of September was 10.75 inches greater in 2017 than in 2016.
The contrast between August and September 2017 is similar to that between September and October 2015: October 2015 was the third wettest October with 11.89 inches, while September 2015 was the sixth driest September with 0.15 inch. Upper air high pressure brought seasonably warm and mostly dry weather through the 5th, though there were isolated showers on the afternoons of the 1st and 2nd. A strong early-season cold front crossed on the evening of the 5th. It was accompanied by scattered showers and thunderstorms with about 50 percent areal coverage. These were mainly over the southeastern half of the region, with amounts ranging from a few hundredths of an inch to nearly two inches. Both amounts and coverage increased from northwest to southeast, with Lufkin reporting the largest amount at 1.88 inches.
The cold front brought northerly to northeasterly winds to the area beginning on the 6th. Combine this with the effects of circulation from the western fringe of Hurricane Irma, and the northerly to northeasterly flow continued through the 13th. The result was a period of below normal temperatures during that time. The presence of upper air high pressure meant that there was almost no rain. The rain exception came on the afternoon of the 12th when the remnant of Irma was centered near Memphis, and a few light sprinkles fell over the eastern counties. Wake Village was the only location in the region to receive anything measurable 0.02 in.
Upper air high pressure built back over the region beginning on the 14th. This sent temperatures back above normal where they remained through the 30th. Weaknesses in the ridge permitted the sea-breeze to spread showers into the southern counties beginning on the 18th. Coverage that afternoon was about 10 percent with Palestine measuring 1.06 inches. Coverage on the 19th and 20th was under 5 percent, rising to around 10 percent on the 21st. The heaviest rain on the 21st was 1.31 inches near Lufkin. Coverage on the 21st and 22nd was under 5 percent, but rose to about 15 percent on the 23rd and 24th. Showers were suppressed by the upper air high between the 25th and 27th.
A cold front eased through the area on the night of the 27th and 28th. This brought showers from the evening of the 27th through the early-morning of the 29th with coverage of about 40 percent, and amounts mostly under one-half inch. Coverage and amounts increased from east to west, with Navarro Mills Reservoir receiving 2.17 inches and Terrell 1.19 inches. Partially fueling these showers was moisture from Eastern Pacific Tropical Storm Pilar, which had resulted in heavy and flooding rains across South and West Texas between the 25th and 28th.
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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September 2017, RECORDS AND SUMMARY: