207
FXUS65 KBOI 300900
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
300 AM MDT SUN MAR 30 2025
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ANOTHER STORM
SYSTEM IS SET TO IMPACT THE REGION LATER TODAY, BEGINNING WITH A
WARM FRONTAL PASSAGE, FOLLOWED BY WIDESPREAD PRECIPITATION AND
A SIGNIFICANT DROP IN TEMPERATURES ON MONDAY AS A COLD FRONT
MOVES THROUGH. ADDITIONALLY, THERE IS A CHANCE FOR A RAIN-SNOW
MIX IN THE SNAKE RIVER PLAIN EARLY TUESDAY MORNING. WITH CLEARER
SKIES AND LIGHT WINDS FOLLOWING YESTERDAY’S PRECIPITATION,
CONDITIONS ARE FAVORABLE FOR VALLEY FOG DEVELOPMENT TOWARD
SUNRISE. FOG HAS ALREADY FORMED IN LONG VALLEY, AND THERE IS AT
LEAST A 30% CHANCE OF FOG IN BAKER VALLEY AND THE TREASURE
VALLEY.
AS OF 2 AM MDT, THE INCOMING STORM SYSTEM IS POSITIONED NEAR
42N AND 135W, APPROACHING THE PACIFIC NORTHWEST WITH A STRONG
WARM FRONT EXTENDING TO THE NORTHERN CALIFORNIA COAST. THIS
FRONT WILL PUSH NORTHEASTWARD TODAY, REACHING THE NEVADA-OREGON
BORDER AROUND NOON MDT, THE SNAKE RIVER PLAIN AND BAKER VALLEY
BY 4 PM MDT, AND THE CENTRAL IDAHO MOUNTAINS BY 6 PM MDT. A BAND
OF LIGHT PRECIPITATION IS EXPECTED ALONG THE FRONT AS IT MOVES
THROUGH. POST-FRONTAL CONVECTIVE SHOWERS, AND POSSIBLY A FEW
THUNDERSTORMS, MAY DEVELOP, THOUGH INSTABILITY REMAINS WEAK,
WITH CAPE VALUES AROUND 100 J/KG AND SHEAR NEAR 25 KNOTS.
SHOWERS WILL INCREASE AHEAD OF THE APPROACHING COLD FRONT
MONDAY MORNING, WITH MORE WIDESPREAD PRECIPITATION LIKELY BY
LATE MORNING AS THE COLD FRONT AND UPPER-LEVEL JET MOVE IN. THIS
WILL FURTHER DESTABILIZE THE ATMOSPHERE, BRINGING A 50% CHANCE
FOR CONVECTIVE SHOWERS CAPABLE OF PRODUCING LIGHTNING, GRAUPEL,
HEAVY RAIN BELOW 4,500 FEET, AND GUSTY WINDS UP TO 35 MPH.
BRIEF, HEAVY SNOW MAY OCCUR WITH STRONGER SHOWERS ABOVE 4,500
FEET, POTENTIALLY LEADING TO UP TO HALF AN INCH OF SNOWFALL. IN
GENERAL, SNOW LEVELS WILL RANGE FROM 4,500 TO 5,500 FEET MSL,
WITH LIGHT SNOWFALL EXPECTED IN MOUNTAIN VALLEYS. AREAS ABOVE
6,500 FEET COULD RECEIVE UP TO 8 INCHES OF NEW SNOW WITH THE
FRONTAL PASSAGE MONDAY.
BY MONDAY EVENING, TEMPERATURES AND SNOW LEVELS WILL DROP TO
AROUND 3,000 FEET. WITH THE UPPER-LEVEL TROUGH LINGERING OVER
THE AREA, SHOWERS WILL CONTINUE FOR MUCH OF TUESDAY, BRINGING A
25% CHANCE OF A RAIN-SNOW MIX IN LOWER ELEVATIONS BELOW 3,000
FEET AT LEAST THROUGH TUESDAY MORNING. SURFACE TEMPERATURES ARE
LIKELY (50% CHANCE) TO STAY AT OR JUST ABOVE FREEZING IN THE
TREASURE VALLEY, MAKING SNOW ACCUMULATION UNLIKELY.
LONG TERM...WEDNESDAY THROUGH SUNDAY
BROAD UPPER TROUGHING WILL
BE IN PLACE MID-WEEK, AND MAINTAIN BELOW NORMAL TEMPERATURES ACROSS
THE ENTIRE REGION. HOWEVER, SIGNIFICANT UNCERTAINTY EXISTS IN THE
POTENTIAL EVOLUTION AND PROGRESSION OF A NORTHERN STREAM DISTURBANCE
THAT MAY DRIFT SOUTHWARD INTO SOUTHERN IDAHO ON THURSDAY, WHICH
WOULD BRING ANOTHER ROUND OF PRECIPITATION. THE PROBABILITY OF
PRECIPITATION ON THURSDAY WILL RANGE FROM 20-30% IN THE LOWER
ELEVATIONS AND 50-70% IN THE MOUNTAINS. SNOW LEVELS WILL BRIEFLY
APPROACH VALLEY FLOORS DURING THE MORNING HOURS, BUT ANY TRAVEL
IMPACTS ARE EXPECTED TO BE LIMITED. A DRYING TREND WILL BEGIN FRIDAY
AS THE INFLUENCE OF AN UPPER-LEVEL ANTICYCLONE INCREASES THROUGH THE
WEEKEND, BRINGING AN INCREASE TO SLIGHTLY ABOVE-NORMAL TEMPERATURES
BY SUNDAY.
AVIATION
LOCALIZED FOG CREATING IFR CONDITIONS AT KMYL THIS
MORNING, BECOMING MOSTLY VFR BY LATE MORNING. BAND OF SHOWERS WILL
MOVE NORTHEASTWARD AFTER 30/18Z, WITH ISOLATED THUNDERSTORM THREAT
DEVELOPING NORTH OF KBOI AFTER 31/04Z. MOUNTAINS OBSCURED. SURFACE
WINDS: SE 8-12 KT.GUSTS OVER 30 MPH IN SOUTHEAST OREGON. WINDS ALOFT
AT 10KFT: SW 20-40 KT.
KBOI...MOSTLY VFR. PERIODS OF CLOUDS THROUGHOUT THE MORNING. SHOWERS
EXPECTED TO DEVELOP AFTER 30/22Z. 10% CHANCE OF A THUNDERSTORM AFTER
31/06Z. SURFACE WINDS: NW 10-15 KT.
HYDROLOGY
COOL SHOWERY CONDITIONS WILL CONTINUE THROUGH MOST
OF NEXT WEEK. SNOW LEVELS WILL REMAIN LOW, AND HEAVY
PRECIPITATION IS NOT EXPECTED AT THIS TIME. HOWEVER, MINOR
FLOODING IS FORECAST TO CONTINUE ON THE SILVIES RIVER NEAR BURNS
AND MALHEUR RIVER NEAR VALE THROUGH THE COMING WEEK.
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
SHORT TERM...JDS
LONG TERM....JR
AVIATION.....JR
HYDROLOGY....JDS
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