A weak weather system is wrapping up this evening, leaving behind moist conditions that will set the stage for patchy valley fog overnight before a beautiful spring-like Tuesday gives way to a much stronger cold front late Wednesday.
Tonight and Tuesday: Fog Then Spring Warmth
Today's light rain will leave lower levels moist, creating favorable conditions for patchy valley fog overnight and early Tuesday morning. Once that fog clears, Tuesday will feel more like mid-April than early March, with temperatures climbing to the lower 60s in southern valleys and upper 40s through 50s elsewhere. It should be a great day to get outside and enjoy the sunshine before the next system arrives.
A couple of lightning strikes have already occurred in southwest Idaho this afternoon, so isolated thunderstorms remain possible in the southwest highlands and near Glenns Ferry until early evening.
My Pick day of the week it Tuesday before a stormy Wednesday
Wednesday Through Thursday: Cold Front and Gusty Winds
The pleasant weather won't last long. A much stronger, colder, and wetter system will approach from the Gulf of Alaska Wednesday, bringing rain showers and a cold front late Wednesday and Wednesday night. Total precipitation through Wednesday night should reach a quarter to half an inch, with snow levels staying above 6,000 feet until near the end of precipitation. The cold front will drop snow levels to 3,500 to 4,500 feet, bringing 3 to 6 inches of snow above 6,000 feet - great news for ski areas after recent warm conditions.
Following the cold front, Thursday will bring gusty winds of 30 to 45 mph across the Snake Plain and highlands, along with colder temperatures dropping to a few degrees below normal. Friday will also see gusty winds of 25 to 35 mph before conditions gradually improve heading into the weekend.
Weekend and Beyond: Warming Then Pattern Change
High pressure building in the north Pacific will drive a warming trend through the weekend, with temperatures reaching 5 to 10 degrees above normal by Sunday, making it the warmest day of the extended period. Mountain snow showers will continue through the weekend with northwest flow maintaining a 40% chance of precipitation each day in the mountains, though accumulations will be minimal and valley rain will be limited.
The pleasant weekend warmth will be short-lived, however. A strong pressure gradient developing north of the Pacific High will support a significant moisture surge through the Pacific and Interior Northwest. Precipitation chances and cloud cover begin increasing Sunday, with a colder and wetter start to next week looking increasingly likely. Recent model trends have been carrying the precipitation farther south with each run, suggesting the region should prepare for a notable pattern change heading into next week.
Tonight
Patchy fog after 2am. Otherwise, partly cloudy, with a low around 35. Light and variable wind.
Tuesday
Mostly sunny and pleasant, with a high near 62. Wind SE 6-10 in the afternoon.
Tuesday Night
Partly cloudy with cold breeze, with a low around 45. East southeast wind 10-15 mph.
Wednesday
Rain developing and spreading from west to east through the morning. High near 57. Gusty wind may develop at times. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Wednesday Night
Rain showers tapering off. Low around 38. Chance of precipitation is 100%. New precipitation amounts between a tenth and quarter of an inch possible.
Thursday
Partly sunny, blustery & cool, with a high near 52.
Thursday Night
Mostly clear, with a low around 33.
Friday
Sunny with a breeze, with a high near 52.
Friday Night
Mostly clear, with a low around 35.
Saturday
Mostly sunny and milder, with a high near 57.
Saturday Night
Mostly cloudy, with a low around 41.
Sunday
Partly sunny & mild, with a high near 61.
Sunday Night
Mostly cloudy, with a low around 41.
Monday
A slight chance of rain. Mostly cloudy, with a high near 56.
