035
FXUS65 KBOI 130035
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
635 PM MDT SUN JUL 12 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- HEAT ADVISORIES IN THE SNAKE PLAIN TODAY AND TOMORROW.
- SHOWERS AND THUNDERSTORMS RETURN MONDAY EVENING THROUGH THE
WEEK.
- TUESDAY AND WEDNESDAY STORMS WILL BE CAPABLE OF HEAVY
DOWNPOURS, POTENTIALLY AFFECTING STEEP TERRAIN AND BURN SCARS.
- HOT TEMPERATURES REMAIN THROUGH THE WEEK.
SHORT TERM /THROUGH TUESDAY NIGHT/
ISSUED 206 PM MDT SUN JUL 12 2026
HIGH PRESSURE TO THE EAST CONTINUES WARM AND DRY SOUTHWESTERLY
FLOW ALOFT, ALTHOUGH A MONSOONAL MOISTURE TAP IS BRINGING
INCREASING CLOUDS TODAY. CLOUDS TODAY WILL MODERATE THE HIGH
TEMPERATURE RELATIVE TO YESTERDAY, BUT WILL ALSO LIMIT COOLING
TONIGHT. AS THE WARM FLOW CONTINUES SO DOES THE WARMING TREND,
BRINGING THE SNAKE PLAIN BACK INTO 100 DEGREE TERRITORY. TODAY,
A HEAT ADVISORY IS IN EFFECT FOR THE MAGIC VALLEY. TOMORROW, THE
WARMER TEMPERATURES HAVE PROMPTED AN EXPANSION OF THE ADVISORY
TO INCLUDE THE REST OF THE SNAKE PLAIN INCLUDING THE TREASURE
VALLEY. MAX TEMPERATURES IN THE HIGH 90S UP TO 101 DEGREES ARE
EXPECTED TOMORROW.
THE WARMING TREND HITS A PLATEAU AFTER MONDAY AS THE MONSOONAL
MOISTURE TAP BRINGS INCREASING CHANCES OF PRECIPITATION AND
STEADY CLOUD COVER. PRECIPITABLE WATER INCREASES FROM THE 90TH
PERCENTILE MONDAY UP TO THE 99TH PERCENTILE TUESDAY. THIS
REFLECTS THE TREND IN PRECIPITATION CHANCES WELL, AS
THERE IS A 10% CHANCE OF PRECIPITATION AND A 10% CHANCE OF
THUNDER ON MONDAY. STORMS WILL BEGIN DRIER INITIALLY AND
BECOME WETTER INTO THE EVENING, ALTHOUGH A 25-45 MPH STORM
MOTION WILL LIMIT ACCUMULATION. CHANCES INCREASE WITH MORE
AVAILABLE ATMOSPHERIC MOISTURE ON TUESDAY, WITH A 40% CHANCE OF
PRECIPITATION AND A 20% CHANCE OF THUNDER. PRECIPITATION IS LESS
LIKELY IN THE TREASURE VALLEY AND WEISER BASIN. WHILE STORMS ON
TUESDAY WILL BE MORE EFFICIENT RAIN PRODUCERS THAN STORMS ON
MONDAY, A FAST STORM MOTION WILL LIMIT ACCUMULATION OVER ANY
GIVEN SPOT. THIS BEING SAID, VULNERABLE AREAS SUCH AS BURN SCARS
AND STEEP SLOPES STILL HAVE A MINOR RISK FOR FLASH FLOODING AND
DEBRIS FLOWS. RAINFALL AMOUNTS DIRECTLY UNDER SHOWERS ON MONDAY
COULD SEE UP TO 0.25 INCHES OF RAIN IN AN HOUR, WHILE ON TUESDAY
UP TO 0.5 INCHES IN AN HOUR IS POSSIBLE. STORMS BOTH DAYS WILL
BE CAPABLE OF GUSTY OUTFLOW WINDS AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES COOL SLIGHTLY TO AROUND NORMAL TUESDAY, WITH MAX
TEMPS IN THE SNAKE PLAIN IN THE MID 90S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ISSUED 206 PM MDT SUN JUL 12 2026
ENSEMBLES AND CLUSTERS HAVE FINALLY (LARGELY) AGREED ON BRINGING THE
UPPER-LEVEL SHORTWAVE IN THE PACIFIC ONSHORE WEDNESDAY INTO
THURSDAY. WHILE THIS WON'T COMPLETELY SHOVE THE MOISTURE FETCH FROM
THE MONSOON TO THE EAST, IT WILL LIMIT HIGHER SHOWER AND
THUNDERSTORM CHANCES TO THE HIGHER TERRAIN MAINLY OVER THE SW IDAHO
MOUNTAINS. DESPITE THIS SHORTWAVE MOVING THROUGH THE REGION,
SOUTHERLY/SOUTHWESTERLY FLOW ALOFT WILL BE MAINTAINED WITH THE UPPER-
LEVEL RIDGE NOT BEING DETERRED OVER THE FOUR CORNERS REGION. PWAT
VALUES AT OR ABOVE 0.8" AREAWIDE WILL CONTINUE THE PRIMARY CONCERN
OF FLOODING, ALTHOUGH THIS FAR OUT IN THE FORECAST PERIOD, LOCATION
AND TIMING IS VERY UNCERTAIN. MODEL SOLUTIONS BEGIN TO DIVERGE AGAIN
FRIDAY THROUGH THE WEEKEND, WITH THE AMPLITUDE OF THE RIDGE IN
QUESTION AS WELL AS POSSIBLE TROUGHING AGAIN OFF THE PACIFIC NW
SHORELINE. MONSOONAL MOISTURE WILL STILL PERMEATE THROUGH THE GREAT
BASIN, BUT ITS NORTHWARD EXTENT IS THE PRIMARY QUESTION, LEADING TO
LOW FORECAST CONFIDENCE OF SHOWERS/THUNDERSTORMS WITHIN THE FORECAST
AREA. OVERALL, SLIGHT CHANCES FOR PRECIPITATION LINGER OVER HIGHER
TERRAIN AS HOT, SOUTH-SOUTHWEST FLOW ATTEMPTS TO DOMINATE THROUGH
THE WEEKEND. SURFACE MAX TEMPERATURES SHOULD REMAIN 5-10 DEGREES
ABOVE NORMAL THROUGH THE FORECAST PERIOD.
AVIATION /00Z MONDAY THROUGH TUESDAY/
ISSUED 628 PM MDT SUN JUL 12 2026
VFR. HIGH DENSITY ALTITUDE DUE TO HEAT. ISOLATED SHOWERS IN
EASTERN OR PRODUCING GUSTY ERRATIC WINDS. AREAS OF SMOKE,
ESPECIALLY NEAR KBKE. WINDS ALOFT AT 10KFT MSL: SW 15-25KT.
SURFACE WINDS: SW-NW 10-20KT THIS AFTERNOON BECOMING LIGHT
OVERNIGHT, THEN W TO NW 5-15 KT MON AFTERNOON.
KBOI...VFR. NW 5-10KT DURING THE AFTERNOON, BECOMING SE 5-10KT
OVERNIGHT. HIGH DENSITY ALTITUDE DUE TO HEAT.
BOI WATCHES/WARNINGS/ADVISORIES
ID...HEAT ADVISORY FROM 2 PM TO 9 PM MDT MONDAY FOR IDZ012-014.
HEAT ADVISORY UNTIL 9 PM MDT MONDAY FOR IDZ016-030.
OR...HEAT ADVISORY FROM 2 PM MDT /1 PM PDT/ TO 9 PM MDT /8 PM PDT/
MONDAY FOR ORZ064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....KA
SHORT TERM...JM
LONG TERM....CH
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