935
FXUS65 KBOI 182107
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
207 PM MST MON NOV 18 2024
SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
ZONAL FLOW
TONIGHT WILL GIVE WAY TO A BRIEF RIDGE ALOFT TUESDAY, AND BY
TUESDAY NIGHT A LONG FETCH OF SW FLOW WILL BECOME ESTABLISHED
ACROSS THE PACNW. THIS FLOW WILL BRING IN AN ATMOSPHERIC RIVER.
SHOWERS WILL CONTINUE TONIGHT INTO TUESDAY, BUT THE SUBSTANTIAL
PRECIPITATION MOVES IN TUESDAY NIGHT AND WILL CONTINUE INTO THE
LONG TERM PERIOD. THE CHANCE OF PRECIPITATION REACHES ITS
MAXIMUM (FOR THE SHORT TERM) WED NIGHT WITH A 50-90% CHANCE
(GOING ROUGHLY FROM SOUTH TO NORTH). SNOW LEVELS WILL INITIALLY
BE ON VALLEY FLOORS, AND WILL REMAIN THERE THROUGH WEDNESDAY
MORNING, BUT WILL RAPIDLY RISE WED AFTERNOON AND NIGHT. BY LATE
WED NIGHT, SNOW LEVELS WILL RANGE FROM AROUND 4000 FT AGL IN
BAKER COUNTY UP TO AROUND 7000 FT AGL IN SOUTHERN HARNEY AND
MALHEUR COUNTIES. THE IDAHO MOUNTAINS WILL BE UP TO AROUND 5000
FT AT THAT TIME. WINDS WILL INCREASE TUE NIGHT INTO WED, WITH
GUSTS 40-50 MPH ON THE HIGHER TERRAIN IN SE OREGON, AND 30-40
MPH IN MUCH OF THE AREA. THIS IS DUE IN PART TO A STRONG SURFACE
LOW OFF THE COAST (WHICH IS ASSOCIATED WITH THE REMNANTS OF A
TYPHOON THAT WAS OFF THE COAST OF ASIA JUST 5 DAYS AGO!).
THROUGH THE ENTIRE SHORT TERM, SNOW TOTALS IN THE MOUNTAINS WILL
RANGE FROM 1-3 INCHES IN PLACES LIKE IDAHO CITY, HALFWAY, AND
GARDEN VALLEY, WITH 5-9 INCHES IN MCCALL, SUMPTER, AND DONNELLY.
UP TO TWO FEET WILL FALL IN THE HIGHEST ELEVATIONS, INCLUDING
IN THE HIGHEST TERRAIN OF BAKER COUNTY TO THE NORTH OF HALFWAY.
THE COMBINATION OF WIND AND SNOW WILL LEAD TO SNOW BLOWING
NEARLY HORIZONTALLY AT TIMES, BUT SNOW ACCUMULATION ON ROADS
SHOULD BE MINIMAL.
LONG TERM...THURSDAY THROUGH MONDAY
SW FLOW ALOFT WILL
CONTINUE THE LONG TERM PERIOD. SNOWFALL WILL CONTINUE AT HIGHER
ELEVATIONS, WITH RAIN BELOW AROUND 7000 FT AGL FROM THU EVENING
THROUGH EARLY SAT MORNING. AFTER THAT TIME, SNOW LEVELS WILL
FALL AGAIN, CHANGING RAIN BACK OVER TO SNOW IN (FOR EX) MCCALL.
LIGHT SNOW IS EXPECTED ABOVE AROUND 3000 FT AGL SATURDAY NIGHT
THROUGH MONDAY. WINDS WILL INCREASE AGAIN AS A SYSTEM MOVES
THROUGH FRIDAY NIGHT AND SATURDAY, WITH GUSTS 20-35 MPH
EXPECTED IN HIGHER TERRAIN AND ALSO OVER MUCH OF SE OREGON.
ANOTHER WEAKER SYSTEM MAY ARRIVE MONDAY, AND THERE IS
SUFFICIENT CONFIDENCE TO KEEP A CHANCE OF PRECIPITATION (30-70%)
IN THE FORECAST.
AVIATION
MOSTLY VFR, BUT SCATTERED SNOW/RAIN SHOWERS THROUGH
THE EVENING, RESULTING IN MVFR TO LIFR AT TIMES. SURFACE WINDS:
SW-NW 10-20 KT WITH GUSTS TO 20-30 KT THIS AFTERNOON. WINDS
ALOFT AT 10KFT MSL: WESTERLY 20-30 KT.
KBOI...MOSTLY VFR BUT WITH SCATTERED SNOW SHOWERS THROUGH 19/02Z.
MVFR/IFR POSSIBLE IN SNOW, WITH BEST CHANCE OF LIGHT ACCUMULATION
DURING THE EVENING. SURFACE WINDS: W-NW 5-15 KT, WITH AFTERNOON
GUSTS UP 20 KT, BECOMING VARIABLE AROUND 5 KT AROUND 19/02Z.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE
SHORT TERM...SP
LONG TERM....SP
AVIATION.....SP
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