Radar — KHNX
Surface Analysis — Western U.S. (South)
Satellite
Nearest monitored road: North First Street (Secondary)
1. High pressure over the region will maintain temperatures near seasonal averages for the remainder of central california today through wednesday, with a warmup commencing thursday.
2. Major heat risk developing thursday for the indian wells valley, mojave slopes and desert, with an extreme heat warning through next monday.
3. Prolonged heat is expected to affect the sj valley this weekend and a heat advisory or extreme heat warning is likely.
4. Seasonably dry conditions to prevail through the week, with no monsoon moisture expected in the mountains. Along with well above normal temperatures, this will produce elevated fire weather concerns late this week into early next week.
Temperatures will be near normal through wednesday as an upper ridge remains centered over the southern plains region and weak upper troughing remains centered over northern ca. A fairly benign surface pressure gradient exists such that most of the area will see light winds under 10 MPH, mostly terrain driven. The exception will be over the tehachapi mtns/mojave desert slopes region where near normal WNW wind gusts over 25 MPH will continue.
Starting thursday, the upper ridge begins its slow westward retrograde intro the desert SW while expanding in strength, with 600 dm heights expected by friday over az. By friday, nbm indicates 60-80% probability for valley-wide high temperatures above 105. There is also a similar high probability for high temperatures above 110 across the mojave desert. Combined with low temperatures in the 70S for the valley and 80S for the desert, the weather prediction center places 50-80% probability for major heat risk across the forecast area this weekend and the start of next work week. We have issued an extreme heat warning for the mojave desert, mojave desert slopes and indian wells valley regions through next monday. A heat advisory or extreme heat warning will likely be needed for the weekend for the remainder of the forecast area.
In addition to the increasing temperatures, minimum afternoon rh readings are expected to fall to as low as 5% in the mojave desert and 12-16% in the san joaquin valley thursday through early next week. Increasing mid level warming will lead to progressively poorer overnight rh recoveries especially in higher terrain/mid slope areas. Though winds will remain mostly diurnal and terrain-driven, the combined deep layer of hot and dry conditions with high haines indices will be favorable for fire growth and spread given seasonably dry and cured fuels. Fire weather products may be issued if more aggressive conditions are expected.
The CPC 6-10 day temperature outlook indicates temps will likely remain well above normal, with a 60-70% probability covering much of california as of their latest outlook. The CPC 8-14 day temperature outlook has slightly lower probabilities of well above normal conditions from 50-60%. This falls in line with indications of a more robust monsoon moisture surge developing into the desert region and possibly the southern sierra nevada later next week as the upper ridge shifts further north.
VFR conditions will prevail for the next 24 hours.
Unhealthy for sensitive groups in eastern tulare county and sj valley portion of kern county.
The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback.