001
FXUS65 KBOI 202104
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
204 PM MST WED NOV 20 2024
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
THE STRONG PACIFIC
LOW WHICH BROUGHT VERY STRONG WINDS LAST NIGHT IS SLOWLY MOVING
NORTHWARD AND WEAKENING. IT IS CONNECTED TO AN ATMOSPHERIC
RIVER WHICH CONTINUES TO FUNNEL DEEP MOISTURE INTO THE REGION,
SUPPORTING WIDESPREAD PRECIPITATION PARTICULARLY OVER THE
MOUNTAINS. OROGRAPHIC EFFECT WILL FOCUS PRECIPITATION OVER
TERRAIN, ESPECIALLY NORTH OF A BURNS-BOISE-FAIRFIELD LINE.
MOUNTAINOUS AREAS CAN EXPECT SNOWFALL TOTALS OF A FEW INCHES,
WITH ACCUMULATIONS EXCEEDING A FOOT ALONG RIDGES AND SUMMITS.
SNOW LEVELS WILL RISE FROM AROUND 5000 FEET MSL TODAY TO 8000
FEET MSL BY FRIDAY MORNING THANKS TO SOUTHWEST FLOW ALOFT AND A
WARMER AIRMASS SETTING IN. THIS WILL SUPPORT RAIN IN LOWER
ELEVATIONS AND A TRANSITION FROM SNOW TO RAIN IN HIGHER
ELEVATIONS EXCEPT FOR THOSE ABOVE 8000 FEET.
MOUNTAINS WILL SEE 1 TO 2 INCHES OF LIQUID EQUIVALENT/RAINFALL
NORTH OF THE AFOREMENTIONED LINE THROUGH THE SHORT TERM. THE
HIGHEST SUMMITS MAY SEE EVEN MORE. THIS AMOUNT OF RAINFALL MAKES
NUISANCE LEVEL PONDING OR SLIDES A SLIGHT CONCERN OVER RECENT
BURN SCARS, BUT NOT ENOUGH FOR A PRODUCT GIVEN THE LONGEVITY OF
THE EVENT. IN LOWER ELEVATIONS DRY AIR NEAR THE SURFACE IS
LIMITING PRECIPITATION EFFICIENCY, BUT WE EXPECT TO HAVE
PRECIPITATION BREAK THROUGH THE DRY LAYER TOMORROW BRINGING A
FEW TENTHS OF AN INCH BY THE END OF FRIDAY. WINDS WILL REMAIN
BREEZY WITH GUSTS UP TO 25 FOR MOST AREAS, HIGHER ALONG RIDGES.
A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE BOISE AND
WEST CENTRAL MOUNTAINS FOR TRAVEL IMPACTS DUE TO SNOW,
PARTICULARLY IN HIGHER TERRAIN. THE ADVISORY LASTS THROUGH 5AM
MST THURSDAY, AT WHICH POINT RISING SNOW LEVELS WILL
SIGNIFICANTLY IMPACT FUTURE SNOWFALL FOR MOST PASSES AND
MOUNTAIN VALLEYS. BANNER SUMMIT WILL CONTINUE TO SEE A FEW
INCHES EVERY SIX HOURS, FOR A FORECAST TOTAL OF 15-20 INCHES
THIS AFTERNOON THROUGH FRIDAY AFTERNOON.
LONG TERM...SATURDAY THROUGH WEDNESDAY...ACTIVE WEATHER TO CONTINUE
AS A TROUGH OF LOW PRESSURE SETTLES OVER THE REGION INTO NEXT WEEK.
THE BULK OF ATMOSPHERIC ENERGY WILL IMPACT THE AREA SATURDAY AS A
COLD FRONT SWINGS THROUGH, LOWERING SNOW LEVELS TO 3500-4000 FEET. A
SERIES OF WEAKER WAVES ARE EXPECTED FOR EARLY IN THE WEEK WITH
ADDITIONAL CHANCES FOR PRECIPITATION. BY WEDNESDAY, ENSEMBLE CLUSTER
ANALYSIS INDICATES SIGNIFICANT UNCERTAINTY IN THE OVERALL PATTERN.
THOSE WITH TRAVEL PLANS SHOULD MONITOR THE SITUATION CLOSELY OVER
THE NEXT SEVERAL DAYS. TEMPERATURES WILL SETTLE BACK TO NEAR
AVERAGE BY EARLY WEEK.
AVIATION
MOSTLY VFR. MVFR/IFR POSSIBLE IN PRECIPITATION, WITH A
FOCUS ON HIGH TERRAIN NORTH AND EAST OF A KBNO-KONO-KBOI-KSUN LINE.
MOUNTAINS OBSCURED. SNOW LEVELS RISING TO 5500-7500 FT MSL LATE
TONIGHT. AREAS OF LOW LEVEL WIND SHEAR CONTINUE INTO THE EVENING
HOURS. . SURFACE WINDS: S TO SE 15-25 KT, GUSTS UP TO 30-45 KT,
BECOMING S TO SE 10-20 KT OVERNIGHT. WINDS ALOFT AT 10KFT MSL: SW 40-
60 KT.
KBOI
VFR WITH OCCASIONAL LIGHT PRECIPITATION AND CLOUDY SKIES.
LOW LEVEL WIND SHEER POSSIBLE. MVFR/IFR CHANCES RISE AFTER 18Z
THURSDAY, BUT ARE LIMITED WITH THE BULK OF ATMOSPHERIC LIFT
REMAINING NE OF THE TERMINAL. SURFACE WINDS: SE 15-25 KT WITH GUSTS
TO 25-35 KT, BECOMING SE 10-20 KT WITH GUSTS TO 25 KT OVERNIGHT.
BOI WATCHES/WARNINGS/ADVISORIES
ID...WINTER WEATHER ADVISORY UNTIL 5 AM MST THURSDAY IDZ011-013.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE
SHORT TERM...JM
LONG TERM....MC
AVIATION.....MC
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