074
FXUS65 KBOI 230326
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
826 PM MST MON DEC 22 2025
DISCUSSION
LATEST RADAR IMAGERY FROM THIS EVENING SHOWS A SWATH OF LIGHT TO
MODERATE PRECIPITATION ACROSS SOUTHERN IDAHO, RELATED TO A BROAD
WARM FRONTAL ZONE THAT WILL SHIFT NORTHWARD OVERNIGHT. RAIN
CHANCES INCREASE TO THE NORTH INTO WEST-CENTRAL IDAHO AND
EASTERN OREGON BY MID-MORNING TUESDAY. SNOW LEVELS WILL REMAIN
SEASONABLY HIGH - GENERALLY BETWEEN 6000 AND 8000 FT MSL. THE
OTHER IMMEDIATE WEATHER CONCERN IS THE PRESENCE OF PATCHY FOG,
PARTICULARLY IN THE LOWER TREASURE VALLEY, WHICH IS EXPECTED TO
BECOME A BIT MORE PREVALENT AS MOISTURE INCREASES OVERNIGHT.
BY LATE TUESDAY MORNING, PRECIPITATION CHANCES WILL QUICKLY END
FROM SOUTH TO NORTH AS THE WARM FRONTAL ZONE CONTINUES ADVANCING
NORTHWARD. TEMPERATURES WILL WARM TO WELL ABOVE NORMAL AGAIN
DURING THE AFTERNOON, ALTHOUGH SOME VALLEY LOW-LEVEL
CLOUDINESS/FOG MAY PERSIST AFTER PRECIPITATION ENDS AND KEEP
TEMPERATURES LOWER IN THOSE SPOTS.
AVIATION
PRECIPITATION WITH MVFR AND LOCALIZED IFR CEILINGS OVERNIGHT.
PATCHY FOG AND LOWER VISIBILITY IN RAIN ALSO LIKELY. MOUNTAINS
OBSCURED. IMPROVING CONDITIONS BY LATE TUESDAY MORNING FROM
SOUTH TO NORTH. KMYL/KBKE WILL SEE MVFR/IFR PERSIST LATER INTO
THE DAY, ALONG WITH RAIN/SNOW MIX. LOCALIZED FOG WITH A 30%
CHANCE OF IFR VISIBILITIES PERSISTING AT KEUL/KONO AFTER 23/18Z.
SURFACE WINDS: S-SE 5-15 KT. WINDS ALOFT AT 10KFT MSL: SW 30-50KT.
KBOI...MAINLY VFR/MVFR. GENERALLY LIGHT RAIN AFTER 23/07Z WITH
CEILINGS APPROACHING 2000 FT. CONDITIONS IMPROVE AFTER 23/16Z AS
PRECIPITATION SHIFTS TO THE NORTH AND LOW-LEVEL CLOUDS ERODE,
BRINGING A RETURN TO VFR. SURFACE WINDS SE 6-10 KT.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...THIS AFTERNOON
THE FRONTAL BAND THAT BROUGHT HEAVY RAIN SUNDAY STILL EXTENDED
ROUGHLY THROUGH YELLOWSTONE- SUN VALLEY- WINNEMUCCA/NV AND STILL
HAS LIGHT RAIN SHOWERS ALONG IT. THE FRONT WILL SHIFT NORTHWARD
AS A WARM FRONT AGAIN TONIGHT THROUGH TUESDAY, DUE TO
STRENGTHENING SSW-LY FLOW ALOFT, WITH PCPN ALSO INCREASING UNDER
AN INTENSIFYING ATMOSPHERIC RIVER (AR) FROM THE PACIFIC SUBTROPICS.
BY LATE TUESDAY THE FRONT WILL BE COMPLETELY NORTH OF OUR CWA
AND CONTINUING TO MOVE NORTH, ALLOWING OUR CWA TO DRY OUT FROM
THE SOUTH, WHILE A COLD FRONT ALONG THE COAST BEGINS TO MOVE
INLAND. OUR CWA WILL THEN BE IN THE "WARM SECTOR" SOUTH OF THE
WARM FRONT AND EAST OF THE COLD FRONT, WITH TEMPS RISING INTO
THE 50S IN THE SOUTHERN CWA VALLEYS. AT THE SAME TIME, SOUTHEAST-
SOUTHWEST SURFACE WINDS WILL BECOME BREEZY IN OUR SOUTHERN
ZONES, AND INCREASE EVEN FURTHER WEDNESDAY MORNING AHEAD OF
THE APPROACHING COLD FRONT, ESPECIALLY IN EASTERN OR. SPEEDS
MAY REACH ADVISORY CRITERIA WEDNESDAY, BUT NOT TO THE MAGNITUDE
OF LAST TUESDAY'S WIND STORM. THE COLD FRONT WILL BRING MORE
PCPN INTO OUR CWA LATE WEDNESDAY, AND ESPECIALLY WEDNESDAY
NIGHT WHEN IT PASSES THROUGH ID. HEAVIEST PCPN IS AGAIN AIMED
AT THE BOISE MOUNTAINS BUT ALL AREAS SHOULD HAVE A PERIOD OF
MODERATE TO HEAVY RAIN AS THE FRONT PASSES. WITH SW-LY WINDS
ALOFT BEHIND THE FRONT TEMPS WILL LOWER ONLY A FEW DEGREES,
WHILE SNOW LEVEL LOWERS ONLY TO AROUND 5000 FEET NORTH TO 7000
FEET SOUTH BY CHRISTMAS MORNING.
LONG TERM...THURSDAY THROUGH MONDAY...A DEEP UPPER LOW OFF THE
COAST OF NORTHERN CALIFORNIA IS EXPECTED TO SLOWLY STEER INLAND
THURSDAY, CONTINUING PRECIPITATION OVER THE AREA. GUSTY RIDGETOP
WINDS AND LOWER SNOW LEVELS ARE EXPECTED THURSDAY THROUGH
SATURDAY. TEMPERATURES THURSDAY WILL STILL BE 10-15 DEGREES
ABOVE NORMAL, COOLING DOWN TO 5 DEGREES ABOVE NORMAL BY SATURDAY
AS THE LOW STEERS ACROSS THE REGION AS A SHORTWAVE TROUGH.
PRECIPITATION IS LIKELY FOR MUCH OF THE AREA AS SNOW LEVELS
THURSDAY DROP FROM 5-6 KFT MSL TO 3-4 KFT MSL BY FRIDAY EVENING.
WHILE THIS BEGINS TO HINT AT WINTRY PRECIPITATION FOR LOWER
ELEVATIONS BY SATURDAY, SNOW LEVELS DROP TO VALLEY FLOORS AS THE
TROUGH AND PRECIPITATION EXIT EAST AND TAPER OFF. LOWER
ELEVATION VALLEYS WILL LIKELY SEE RAIN FRIDAY, WHILE MOUNTAINS
WILL SEE SNOW THROUGH SATURDAY EARLY MORNING. OTHERWISE, MOSTLY
DRY CONDITIONS SATURDAY THROUGH MONDAY. SATURDAY NIGHT THROUGH
MONDAY, TEMPS HOLD STEADY AT JUST ABOVE NORMAL FOR THIS TIME OF
YEAR AS MOST OF THE GUIDANCE SUGGESTS A RIDGE BUILDING OVERHEAD
OFF THE PACIFIC. THE RIDGE AND INCREASING HEIGHTS ALOFT WITH
TEMPS HOLDING STEADY SHOWS SOME EARLY SIGNS OF A POTENTIAL
INVERSION. IF ANY INVERSION DOES FORM, IT MAY SHORTLIVED AS THE
EXTENDED FORECAST SHOWS A RETURN TO UNSETTLED WEATHER NEXT
WEEK.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
DISCUSSION...JR
AVIATION.....JR
SHORT TERM...LC
LONG TERM....JY
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