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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.

May 16 2016
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
Cooler air is beginning to move into the region as a Pacific low pressure system in the northwest U.S. begins to deepen and sag further south. The Pacific low is forecast to move into the southwestern states early this week persisting through Wednesday. This will provide even cooler temperatures along with slight chances of showers and thunderstorms Tuesday. Clearing skies with rebounding temperatures are forecast for late in the week.

A low pressure system near the Great Basin will continue to create a deep marine layer with extensive night and morning low clouds and patchy drizzle over the coast, valleys and coastal foothills and slopes through Tuesday. Only partial clearing is expected west of the mountains each day, with more sunshine by Wednesday. Increasing moisture and instability from a low pressure system could produce a few showers and thunderstorms Tuesday afternoon over the mountains and deserts. Otherwise, a slow warming trend is expected to continue through Thursday with the marine layer becoming a bit shallower each day. Another low pressure system will bring cooling, gusty west winds in the deserts, and deepening of the marine layer for Friday into the weekend.

On water vapor satellite, a low pressure system can be seen over southern Idaho/Northern Nevada/Northern Utah. This low will move south through Tuesday, eventually moving through extreme southeast California/Arizona late Tuesday, with an upper wave with wrap-around mid-level moisture and instability bringing the possibility of showers to the mountains and deserts Tuesday afternoon and evening. Models indicate 500 j/kg of surface based CAPE and near 900 j/kg of most unstable CAPE, so thunderstorms are a possibility over those areas as well. There`s a small chance of some isolated showers over the mountains Wednesday afternoon/evening as the trough moves to the east and northerly flow aloft prevails, but the chance is too minimal to include in the forecast at the moment.

Warming, with a gradually shallower marine layer and better day-time clearing look to occur Tuesday through Thursday, as 700 mb heights and 850 mb temperatures rise over the region. By Thursday, highs may rise to near to slightly above normal. However, cooling is expected to return Friday and continue through the weekend as a low pressure system moves over the Pacific Northwest and meanders over that region. This will also create stronger onshore flow and deepening of the marine layer up to near 4000 ft MSL, with perhaps patchy drizzle at times and only partial clearing during the day. With onshore pressure gradients increasing to 10-13 mb from San Diego to Las Vegas during that time, expect periods of strong and gusty west winds in the mountains and deserts, with gusts of 50-60 mph possible
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