488
FXUS65 KBOI 191725
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1125 AM MDT THU MAR 19 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- RECORD HIGH TEMPERATURES TODAY AND TOMORROW WITH DRY
CONDITIONS.
- BREEZY CONDITIONS AND LOW RELATIVE HUMIDITY WILL CREATE FIRE
DANGER CONCERNS FOR AREAS NEAR THE NV BORDER THURSDAY AND
FRIDAY AFTERNOONS.
- A PATTERN SHIFT WITH A COLD FRONT ON SATURDAY WILL BRING
COOLER TEMPERATURES, MOUNTAIN PRECIPITATION, AND BREEZY
WESTERLY WINDS.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED 308 AM MDT THU MAR 19 2026
THE RIDGE OF HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE
REGION THROUGH THE END OF THE WORK WEEK. RECORD HIGHS WILL
CONTINUE UNTIL A COLD FRONTAL PASSAGE ON SATURDAY. VALLEYS WILL
SEE TEMPERATURES IN THE UPPER 70S TO LOW 80S, WITH MOUNTAIN
LOCATIONS EXCEEDING THE 60 DEGREE MARK. DRY CONDITIONS WITH LOW
RELATIVE HUMIDITY VALUES LESS THAN 15% WILL ACCOMPANY THESE HIGH
TEMPERATURES. ELEVATED AFTERNOON WIND GUSTS WILL INCREASE FIRE
DANGER TODAY AND TOMORROW IN PRE-GREEN UP LOWER ELEVATIONS
SOUTHWEST OF THE SNAKE RIVER VALLEY AND THE NV BORDER. BY MIDDAY
SATURDAY, THE COLD FRONT WILL MOVE THROUGH THE REGION BRINGING
A 10-15 DEGREE TEMPERATURE DROP, CLOUDY SKIES, MOUNTAIN
PRECIPITATION IN SOUTHWEST IDAHO (30-50% CHANCE), AND BREEZY
WESTERLY WINDS. SNOW LEVELS WILL STAY ABOVE 8000 FEET ON
SATURDAY, WITH MINIMAL RAINFALL ACCUMULATIONS OF LESS THAN A
TENTH OF AN INCH WITH THE FRONTAL PASSAGE AS WELL. INSTABILITY
REMAINS WEAK, PRIMARILY DUE TO DRY AIR ALOFT, WITH VERY LOW
CONFIDENCE IN ANY CONVECTION DURING THE FRONTAL PASSAGE.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED 308 AM MDT THU MAR 19 2026
ZONAL FLOW ALOFT WILL HELP PUSH COLD AIR OVER THE PACIFIC
NORTHWEST ON SUNDAY. CONDITIONS WILL GENERALLY BE DRY, WITH
COOLER TEMPERATURES NEAR NORMAL ON SUNDAY AND MONDAY. A RIDGE OF
HIGH PRESSURE WILL BUILD IN BRIEFLY ON TUESDAY, WITH
TEMPERATURES RISING ABOVE 70F IN THE VALLEYS. BY WEDNESDAY, A
TROUGH EXTENDING FROM A LOW OFF THE BRITISH COLUMBIA COAST WILL
MOVE IN TO THE REGION, BRINGING ANOTHER PUSH OF COLD AIR AND
INCREASED CHANCES OF PRECIPITATION. THUNDERSTORMS CANNOT BE
RULED OUT WITH THIS INITIAL FRONTAL PASSAGE, BUT CURRENT
FORECASTS SHOW LOW INSTABILITY OVER THE REGION. THE BEST CHANCE
FOR SHOWERS (20-40%) REMAINS OVER HIGH TERRAIN IN SOUTHWEST
IDAHO, WITH SNOW LEVELS STAYING HIGH INITIALLY AT JUST OVER 8000
FEET MSL. ONCE THE COLDER AIR MOVES IN, SNOW LEVELS WILL DROP
TO 6000-7000 FEET BY LATE WEDNESDAY. SHOWERS WILL TAPER OFF ON
THURSDAY, WITH COOL AND DRY CONDITIONS RETURNING.
AVIATION /18Z THURSDAY THROUGH FRIDAY/
ISSUED 1125 AM MDT THU MAR 19 2026
VFR UNDER HIGH CLOUDS. SURFACE WINDS: VARIABLE UP TO 12 KT,
EXCEPT W-SW 5-10 KT WITH GUSTS UP TO 22 KT IN SE OREGON THIS
AFTERNOON. WINDS ALOFT AT 10 KFT MSL: W-SW 15-30 KT.
KBOI...VFR. SURFACE WINDS UNDER 10 KT, LEANING NW THIS AFTERNOON
THEN SE OVERNIGHT.
WEEKEND OUTLOOK...GENERALLY VFR, A COLD FRONT WILL BRING BREEZY
WINDS AND LOCALIZED MVFR/IFR CONDITIONS IN SHOWERS NEAR KMYL AND
KBKE ON SATURDAY. SURFACE WINDS: W-NW 5-15 KT WITH GUSTS TO 35
MPH ON SATURDAY PM, OTHERWISE VARIABLE LESS THAN 10 KT.
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
AVIATION.....NF
SHORT TERM...SA
LONG TERM....SA
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