Dense Fog — Aguila Valley, Arizona

2018-09-20 · Aguila Valley, Arizona

Event narrative

High morning humidity in combination with generally clear skies and light winds allowed for the formation of patchy dense fog to the southeast of Phoenix on September 30th. According to an NWS employee located about 5 miles south of Apache Junction and near the intersection of Elliot Road and Meridian Road, dense fog resulted in visibility lowering to 1/16 of a mile at about 0600MST. At about the same time, a trained spotter 2 miles southeast of Apache Junction reported dense fog. A Dense Fog Advisory was issued for the area at 0643MST and it remained in effect through 0900MST. Fortunately there were no reports of accidents as a result of the low visibility and associated hazardous driving conditions.

Wider weather episode

High morning humidity combined with generally clear skies and light winds to allow for the formation of dense fog during the morning hours across the lower deserts southeast of Phoenix. The fog only lasted for two to three hours, and began around 0500MST across portions of northwest Pinal County as well as areas around Queen Creek and Apache Junction. Most of the dense fog reports were actually readings from automated weather stations such as the AWOS station in Casa Grande, which registered a visibility at one quarter of a mile. The lowest visibility reported, 1/16 of a mile, was from a NWS employee about 5 miles south of Apache Junction. No accidents were reported despite the sharply reduced visibility and associated hazardous driving conditions.

Source: NOAA Storm Events Database, event_id 780049. Narrative written by the NWS forecast office that issued the report.