916
FXUS65 KBOI 060248
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
848 PM MDT THU JUN 5 2025
DISCUSSION
WEAK UPPER TROUGH OVER THE INTERIOR NORTHWESTERN
US DEVELOPED SHOWERS IN CENTRAL AND EASTERN IDAHO THIS AFTERNOON.
SKIES STAYED SUNNY IN WESTERN IDAHO AND EASTERN OREGON. THE
TROUGH WILL EXIT EAST FRIDAY ALLOWING A BROAD PACIFIC UPPER
RIDGE TO BRING WARMER AIR TO OUR CWA THROUGH THE WEEKEND. MONDAY
AND TUESDAY NOW LOOK LIKE THE HOTTEST DAYS WITH HIGH TEMPS IN
THE 90S IN THE VALLEYS AND 80S IN THE MOUNTAINS, I.E., SLIGHTLY
LATER THAN PREVIOUSLY FORECAST. GRADUAL COOLING BEGINNING LATE
TUESDAY. ALSO, A SLIGHT (10-20 PERCENT) CHANCE OF THUNDERSTORMS
BEGINNING MONDAY AFTERNOON. NO UPDATES.
AVIATION
VFR WITH DIURNAL WINDS OVERNIGHT. SOME CUMULUS
DEVELOPING FRIDAY AFTERNOON AS A WEAK DISTURBANCE MOVES THROUGH
THE NORTHWEST. LESS THAN A 10% CHANCE OF SHOWERS, MAINLY OVER
THE MOUNTAINS OF CENTRAL IDAHO. SURFACE WINDS: MOSTLY VARIABLE
LESS THAN 10 KT BECOMING W-NW 5-10 KT FRIDAY AFTERNOON. WINDS
ALOFT AT 10KFT MSL: NW-N AROUND 10-15 KT.
KBOI...VFR. WINDS LESS THAN 10 KT, BECOME NW 8-12 KT AFTER 18Z
FRIDAY.
WEEKEND OUTLOOK...VFR. BUILDING HEAT WILL RESULT IN HIGH DENSITY
ALTITUDE, ESPECIALLY SUNDAY INTO MONDAY. GENERALLY LIGHT WEST TO
NORTHWEST WINDS SURFACE AND ALOFT.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...WEAK TROUGHING
ALOFT CONTINUES TO SUPPORT A 20% CHANCE OF PRECIPITATION IN THE
CENTRAL IDAHO MOUNTAINS, THOUGH MOSTLY OUTSIDE OF OUR AREA. IN
EASTERN VALLEY AND BOISE COUNTIES THE CHANCE OF PRECIPITATION
IS 10%, AS WELL AS A 10% CHANCE OF THUNDER. THIS IS A SLIGHT
REDUCTION FROM THIS MORNING AS THE TROUGH HAS PROGRESSED EAST
SLIGHTLY FASTER THAN EXPECTED. GUSTY OUTFLOWS UP TO 25 MPH ARE
POSSIBLE NEAR SHOWERS. HIGH PRESSURE WILL BUILD IN BEHIND THE
TROUGH, CONTINUING A WARMING AND DRYING TREND THROUGH THE SHORT
TERM. TEMPERATURES WARM BY ABOUT 5 DEGREES EVERY DAY, UP TO
10-15 DEGREES ABOVE NORMAL BY SATURDAY AFTERNOON. THE PEAK OF
THE WARMING COMES IN THE LONG TERM.
LONG TERM...SUNDAY THROUGH THURSDAY...A STRONG UPPER-LEVEL RIDGE
WILL BUILD IN ACROSS THE NORTHWEST REGION THIS WEEKEND AND HOLD IN
PLACE UNTIL MONDAY. THE HEAT WILL PEAK SUNDAY AND MONDAY WITH LOWER
ELEVATIONS REACHING THE UPPER 90S. THERE REMAINS A 5-10% CHANCE OF
PEAK AFTERNOON/EARLY EVENING TEMPERATURES REACHING OR EXCEEDING 100
DEG FOR MOST VALLEY AREAS ON THOSE TWO DAYS. THERE IS BETTER
GUIDANCE ON THE ARRIVAL OF AN UPPER-LEVEL TROUGH EXPECTED TO BREAK
DOWN THE RIDGE MONDAY TO WEDNESDAY. FOR NOW, FORECAST GUIDANCE HAS A
20-30% CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS HIGHER TERRAIN
MONDAY TO WEDNESDAY. IF THIS SYSTEM HOLDS TOGETHER AS CURRENT
GUIDANCE SHOWS, WOULD EXPECT PROBABILITIES TO INCREASE, EVEN AT
LOWER ELEVATIONS. THURSDAY IS MOSTLY DRY WITH LINGERING HIGH
ELEVATION SHOWERS AS A BROAD TROUGH REMAINS POSITIONED ALONG THE
WEST COAST, WITH SOME DEGREE OF UNCERTAINTY OVER THE TIMING AND
ARRIVAL. AFTER TOPPING OUT AROUND 15 DEGREES ABOVE NORMAL
SUNDAY/MONDAY, TEMPERATURES PULL BACK TO AROUND 10 DEGREES ABOVE
NORMAL WEDNESDAY/THURSDAY. AFTERNOON RELATIVE HUMIDITY LEVELS ARE
EXPECTED TO REMAIN ON THE LOWER END (10-20%) THROUGHOUT THE EXTENDED
FORECAST PERIOD FROM SUNDAY TO THURSDAY.
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
DISCUSSION...LC
AVIATION.....MC
SHORT TERM...JM
LONG TERM....JY
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