801
FXUS65 KBOI 180518
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1118 PM MDT FRI APR 17 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- WIDESPREAD SUBFREEZING TEMPERATURES AGAIN TONIGHT.
- DRIER AND WARMER THROUGH TUESDAY.
- COOLER AND UNSETTLED LATE TUESDAY INTO WEDNESDAY WITH VALLEY
RAIN AND MOUNTAIN SNOW.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED 204 PM MDT FRI APR 17 2026
A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE AREA OVER THE NEXT
SEVERAL DAYS WITH A WARMING TREND EACH DAY THROUGH MONDAY.
TEMPERATURES WILL WARM AROUND 10 DEGREES ON SATURDAY AND AN
ADDITIONAL 10 DEGREES ON SUNDAY. AS THE RIDGE STRENGTHENS, THE
SURFACE WINDS SHIFT TO SOUTH-SOUTHEAST AIDING IN THE WARMING AS
WELL WITH BREEZY CONDITIONS DURING THE AFTERNOONS THROUGH
MONDAY.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED 204 PM MDT FRI APR 17 2026
A CLOSED LOW WILL RESIDE ALONG THE WEST COAST EARLY NEXT WEEK,
PULLING WARM SOUTHERLY AIR INTO SE OREGON AND SW IDAHO. THIS
FLOW PATTERN WILL CONTINUE UNSEASONABLY WARM TEMPERATURES 10-15
DEGREES ABOVE NORMAL ON MONDAY. TUESDAY WILL CONTINUE TO SEE
TEMPERATURES 10- 15 DEGREES ABOVE NORMAL, BUT WITH SOME
CONFIDENCE UNCERTAINTY IN TEMPERATURE MAXIMUMS. PRECIPITATION
WILL BEGIN TO INCREASE ACROSS E OREGON LATE TUESDAY AS THE
CENTER OF THE LOW SHIFTS INLAND AND GETS GRADUALLY SWALLOWED BY
A LONGWAVE TROUGH STEERING OVER BRITISH COLUMBIA. THIS MERGING
SYSTEM WILL GENERATE BREEZY SURFACE WINDS AND WIDESPREAD
PRECIPITATION OVER THE AREA WEDNESDAY AND THURSDAY. WEDNESDAY
WILL SEE THE HIGHEST LIKELIHOOD OF PRECIPITATION AT 50-80% FOR
THE AREA. HIGH MOUNTAIN SNOW WILL ACCUMULATE AS SNOW LEVELS
LOWER TO 5000-7000 FT MSL. A COOLING TREND FROM THIS SYSTEM WILL
RETURN TEMPERATURES BACK TO NEAR-SEASONAL NORMALS WEDNESDAY TO
FRIDAY. BY FRIDAY, LATEST LONG-RANGE GUIDANCE SUGGESTS A
RELATIVELY DRY SHORTWAVE TROUGH BREAKING OFF FROM THE MERGED LOW
AND DIGGING INTO OUR AREA AND THE GREAT BASIN. OVERALL
PRECIPITATION IS EXPECTED TO TAPER OFF BY LATE FRIDAY, WITH
MAINLY MOUNTAIN AREAS SEEING A 20-30% CHANCE OF SHOWERS FROM
REMNANT MOISTURE.
AVIATION /06Z SATURDAY THROUGH SUNDAY/
ISSUED 1117 PM MDT FRI APR 17 2026
VFR UNDER HIGH CLOUDS. SURFACE WINDS: VARIABLE LESS THAN 10 KT,
BECOMING S-SE 5-15 KT AFTER SAT/16Z. GUSTS TO 20 KT IN THE LOWER
SNAKE PLAIN INTO KBKE. WINDS ALOFT AT 10KFT MSL: W-NW 5-15 KT,
BECOMING SW AFTER SAT/12Z.
KBOI...VFR. SURFACE WINDS: SE 7-14 KT. GUSTS TO 20 KT EARLY IN THE
AFTERNOON.
SUNDAY OUTLOOK...CONTINUED DRY WITH PERIODS OF HIGH CLOUD COVER.
SURFACE WINDS S-SE 10-20 KT WITH GUSTS TO 25 KT, STRONGEST IN SNAKE
PLAIN EAST OF KBOI.
BOI WATCHES/WARNINGS/ADVISORIES
ID...FREEZE WARNING UNTIL 10 AM MDT SATURDAY FOR IDZ012-014-016.
OR...FREEZE WARNING UNTIL 10 AM MDT /9 AM PDT/ SATURDAY FOR ORZ064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....ST
SHORT TERM...KA
LONG TERM....JY
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