407
FXUS65 KBOI 181811
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1211 PM MDT SAT APR 18 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- FREEZE AGAIN THIS MORNING IN THE AGRICULTURAL VALLEYS.
- DRY AND WARMING THROUGH MONDAY.
- SHOWERS AND THUNDERSTORMS AND TURNING COOLER TUESDAY AS A
PACIFIC COLD FRONT MOVES INLAND.
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED 316 AM MDT SAT APR 18 2026
FREEZE WARNING IN THE AGRICULTURAL AREAS OF THE TREASURE AND
MAGIC VALLEYS WILL REMAIN IN EFFECT UNTIL 10 AM MDT. TONIGHT'S
LOWS WILL BE GENERALLY IN THE MID TO UPPER 30S AND NO FURTHER
FREEZE IS EXPECTED.
HIGH PRESSURE ALOFT IN THE EASTERN PACIFIC WILL BUILD INLAND
TODAY AND SUNDAY AND REMAIN THROUGH MONDAY, BRINGING DRY
WEATHER WITH A STEADY WARMING TREND. HIGH TEMPS WILL WARM AROUND
10 DEGREES EACH DAY, WHILE LOWS WARM ABOUT 5 DEGREES PER DAY.
SURFACE WINDS WILL BECOME SOUTH-SOUTHEAST AND GUSTY IN THE
AFTERNOONS.
LONG TERM /TUESDAY THROUGH SATURDAY/
ISSUED 316 AM MDT SAT APR 18 2026
WELL-ABOVE NORMAL TEMPERATURES AND BREEZY SOUTHERLY WINDS ARE
ANTICIPATED TUESDAY AHEAD OF AN APPROACHING COLD-CORE PACIFIC LOW.
THIS LOW WILL BRING SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS
INTO E OREGON AND SW IDAHO TUESDAY EVENING INTO WED. WEDNESDAY WILL
BECOME THE WETTEST DAY, WITH THE PROBABILITY OF PRECIP CLIMBING TO
60-90% FOR THE MORNING AND AFTERNOON. SNOW LEVELS WILL ALSO LOWER
TO 5000-6500 FT MSL AT THAT TIME AS THE LOW CENTER MOVES OVERHEAD,
ALLOWING SNOW ACCUMULATION OVER THE HIGHER TERRAIN. SURFACE
WINDS WILL INCREASE WED AFTERNOON AS THEY SHIFT TO WESTERLY, AND
MAX TEMPERATURES ARE FORECAST TO DROP AS MUCH AS 20-25 DEGREES
FROM TUESDAY TO WEDNESDAY. SHOWERS AND BELOW NORMAL TEMPERATURES
WILL PERSIST INTO THURSDAY AS THE UPPER LOW BECOMES INGESTED
INTO THE PARENT CANADIAN TROUGH TO THE NORTH. THIS WILL SOLIDIFY
COOL AND UNSETTLED NORTHERLY FLOW ACROSS THE N ROCKIES AS THE
LOW PROGRESSES EAST, WITH LINGERING MOUNTAIN SHOWERS EXPECTED
INTO FRI. THE 500MB PATTERN STARTS TO BECOME DISORGANIZED FRIDAY
AND BEYOND AS MODELS STRUGGLE TO DEPICT THE MORPHOLOGY OF THE
TROUGH, RESULTING IN LESS FORECAST CONFIDENCE IN PRECIP/TEMPS
FOR FRIDAY INTO THE WEEKEND.
AVIATION /18Z SATURDAY THROUGH SUNDAY/
ISSUED 1209 PM MDT SAT APR 18 2026
VFR UNDER HIGH CLOUDS. SURFACE WINDS: E-SE 5-15 KT. GUSTS TO 20
KT IN THE LOWER SNAKE PLAIN INTO KBKE. WINDS ALOFT AT 10KFT
MSL:SW-S 5-15 KT.
KBOI...VFR. SURFACE WINDS: SE 7-14 KT. GUSTS AROUND 20 KT
THROUGH THE AFTERNOON.
SUNDAY OUTLOOK...CONTINUED DRY WITH PERIODS OF HIGH CLOUD COVER.
SURFACE WINDS E-SE 10-20 KT WITH GUSTS TO 25 KT, STRONGEST IN
SNAKE PLAIN EAST OF KBOI.
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.....CH
SHORT TERM...LC
LONG TERM....SH
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