Wet weather could challenge rain records for the dateSep 12, 2013 From staff reports
Thursday shaped up as one of the wettest in local history for the date, with steady rainfall dousing Fremont County for much of the day following a damp Wednesday as well.
The National Weather Service has posted a flash flood watch for the upper Wind River Basin and the southern half of the Absaroka Mountains in central Wyoming.
Lander bore a heavier brunt than Riverton. Rainfall began Wednesday and left .68 inch of precipitation before midnight. Rain continued throughout the morning and early afternoon Thursday, and by 1:30 p.m. another .60 inch had been recorded in the county seat.
Precipitation was lighter in Riverton on Wednesday, with .02 inch registered by midnight. By 1:30 p.m. Thursday, however, an additional .58 inch had fallen.
Riverton's record precipitation on Sept. 12 is .76 inch, set in 1942. Lander's record for the date is 1.31 inches in 1903.
The timing of storms affects record setting. The 24-hour storm total for Lander could challenge the 1.31 inch, but because the date changed in the midst of the rainfall, the old record could stand.
Meteorologists at the National Weather Service in Riverton warned that the rain could cause flash flooding along small streams and some road areas. Rock and mud slides are possible in the mountains. The weather service says rain showers and isolated thunderstorms Thursday could be expected to produce moderate to heavy rain. Rainfall amounts of 1 to 2 inches remained possible in the flood regions through Thursday.
The sudden change in the weather put an end to what had been an unseasonably hot September, when several 90-degree high temperatures had been recorded for Riverton. Wednesday's high was just 64, 11 degrees cooler than the 75-degree average for the date.
There was no danger of frost, however. Nighttime temperatures this week are predicted to remain in the upper 40s to low 50s.
Improving weather is in the forecast for the weekend, but late-summer conditions are not expected to return until next week.