Unisys

Surface pressure graphic as of 5 a.m. suggests more down slope winds today for continuing high fire danger. Wind is air moving from higher pressure to lower down gradients, or slopes; the larger the gradient between two places, the stronger the wind. Air pressure is measured in millibars (mb). The color contours on this graphic show 2-mb intervals, with higher pressure to our north and northeast. Pressure gradients between Medford and Redding aren't as steep as we've seen the past few days, but are forecast to stay in the 3-to-5 mb range all day (for comparison, the Medford-Redding gradient was over 10 mb at times Thursday and Friday).

San Jose State Meteorology

This chart shows temperatures forecast at the 850 millibar (mb) in the atmosphere, or roughly 5,000 feet overhead, at 5 p.m. today. Forecasters can look to temperatures at this level for clues of weather warmer or colder air is on the way. 850 mb temperatures today over the far northern Sacramento Valley will be about 15 degrees C today compared to about 8 degrees C on Sunday, 5 degrees C on Saturday and 4 degrees C on Friday.

Unisys

Forecast ridge-trough pattern aloft and surface pressure pattern for 5 p.m. today suggests a warm, sunny day ahead with easing winds. The color contours represent the elevation in decameters above sea level of the 500 mb height surface, which varies with air mass warmth. Warmer air, being more expansive, pushes the 500 mb surface higher into space. The oranges and dark oranges over California suggest 500 mb height levels in the 582-to-588-decameter range, which is much higher than normal for this time of year -- an indication of significant warming on the way. The black isobars, or lines of equal surface pressure, are key to forecasting wind speed and direction. The isobars are widely spaced over Northern California, suggesting weaker pressure gradients and lighter winds.

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UPDATE 5 p.m.

Redding peaked out at 84 degrees today, about as predicted.

Steady north winds were somewhat stronger than expected, hitting sustained speeds of 21 mph and gusting to 28 mph.

Winds have eased and will likely die off later tonight.

The National Weather Service expects to end its Red Flag Warning for high fire danger in the valley and lower foothills at 7 p.m. as the dry north winds die off.

Nearly calm conditions and dry air in place will allow an inversion to form overnight, leading to much cooler temperatures Tuesday morning than we saw on the valley floor this morning. Expect low 40s and perhaps some high 30s.

Tuesday should bring light winds and continued brilliant autumn sunshine. Afternoon temperatures in the Redding area will likely top out in the 84-to-87 degree range, which is well above average.

END UPDATE

Dramatically warmer weather is on the way.

Temperatures today could surge toward the mid-80s after days of blustery breezes. The average high in Redding on this date is 80 degrees.

North winds blowing up to 15 mph and gusting to 25 mph could goose afternoon temperatures as they flow down slope and warm with compression.

These dry winds combined with warming temperatures have prompted the National Weather Service to continue its Red Flag Warning for high fire danger through today.

Look for winds to peak this morning and ease this afternoon.

Skies should stay clear, save maybe for a few high clouds drifting over the mountains north of the valley later this afternoon toward evening.

Mild morning so far

North-to-northwest winds blowing steadily through the night have kept air well mixed and an inversion from forming despite the dry air still in place.

Early morning temperatures this morning have been running in the mild mid-50s, with a few 40s in wind-sheltered spots.

Those temperatures will drop like a stone before sunrise should the winds suddenly die -- and they might yet. But frost seems unlikely, given how far temperatures would have to fall.

Lots of warm, bright, breezy weather ahead

Forecasts indicate little variation in the fair, dry, occasionally breezy weather pattern this week.

Bright sunshine and down slope winds will keep visibility sharp and help afternoon temperatures warm into the 80s each day. Slight cooling could come Wednesday, but temperatures rebound Thursday.

Early-morning temperatures will either be mild or chilly, depending on whether the wind dies away before dawn. Local wind patterns are difficult to predict.

Right now, it looks like valley winds could die away Tuesday morning for much cooler temperatures than we're seeing so far today.

Weekend looks cooler, but dry for now

Longer-range forecasts show a weak trough developing over the west coast and dipping toward Northern California starting Friday afternoon.

Redding postponed its annual fireworks extravaganza from July 4 to Oct. 18 -- Saturday -- because of this summer's monster forest fires. A rainout this weekend would be ironic.

Rain doesn't look likely at this point -- not Saturday evening, at least. The trough looks too weak to generate much more than some clouds and cool afternoon highs back into the seasonal upper-70s.

Rain early next week?

Some forecasts suggest the trough might deepen later Sunday into Monday for higher precipitation probabilities, though nothing looks impressive at this point.

Long-range consensus shows fair and dry weather returning (if it ever leaves) and holding through Oct. 27.

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