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Old Advisory Events

The information herein is NOT intended for use as a weather forecast. The Air District DOES NOT forecast but solely compiles information from both the Phoenix and San Diego National Weather Offices to relay information concerning potential changes in ambient air concentrations that may impact the public.

September 22 2017
Be Advised
High wind levels have the potential to suspend particulate matter into the air. High levels of PM10 may pose an impact to public health. It is recommended that active children and adults, and people with respiratory disease, such as asthma, limit their outdoor activities.

Potential increases in PM10 concentrations may increase to moderate or unhealthy level.

Imperial County Weather Synopsis
AUTUMN officially began on September 22 at 102 PM.

A low pressure trough covering the West will continue the cool weather through Saturday. The trough will weaken early next week, allowing offshore flow to develop, bringing much warmer and drier days, and clear, cool nights. Northeast winds could get gusty at times below offshore wind-prone passes and canyons at times. The northerly flow on the west side of the trough along with offshore pressure gradients will get the offshore flow going on schedule Sunday. That will sweep all clouds away and crank up some northeast winds. The strongest winds will appear in foothills and locally into valleys, primarily in and below the Cajon Pass. That`s because the offshore pressure gradient from Nevada is northerly, so San Diego County will not be in a favorable position for strong winds. Monday and Tuesday look like the strongest wind days overall, although offshore flow will continue all week. Temperatures will slowly and gradually rise a couple degrees each day as high pressure aloft slowly and gradually builds.

A low pressure system and cold front that is now sweeping through the southwest will bring substantially cooler temperatures across the region this weekend. Occasionally breezy conditions will also be common across the area. Temperatures will only slowly warm back to near average next week. The continued slow progression of this upper low center across the Great Basin will keep enough cold air in place to keep temperatures well below normal through the weekend. As a result, lower desert high temperatures will likely be kept in the 80s at many locations on Saturday and Sunday. This cool airmass, combined with clear skies and low dewpoints (20`s and 30`s) will also allow temperatures to drop smartly each night, with lows in the 50`s likely at many outlying lower desert locations. Afternoon breeziness can also be expected each day as the very cool air aloft helps to mix stronger winds aloft down to the surface during the warmest part of the day.
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