322
CXUS55 KBOI 011744
CLMBOI
CDUS45 KBOI 011635
CLIBOI
CLIMATE REPORT
NATIONAL WEATHER SERVICE BOISE ID
1035 AM MDT FRI SEP 01 2023
WITH 2.51 INCHES TOTAL PRECIPITATION, THIS WAS THE WETTEST AUGUST ON
RECORD AT ALL OFFICIAL BOISE LOCATIONS GOING BACK TO 1878.
THE 1.46 INCH RAINFALL ON THE 26TH WAS THE SECOND WETTEST ONE-DAY
PRECIPITATION IN AUGUST, AFTER THE 1.61 INCH TOTAL ON AUGUST 13,
1979. IT WAS THE NINTH WETTEST ONE-DAY TOTAL FOR ANY MONTH. AND THE
.37 INCH RAINFALL ON THE 21ST WAS THE LARGEST AMOUNT EVER RECORDED
ON THAT DATE.
WITH AN AVERAGE TEMPERATURE OF 77.9 DEGREES, IT WAS THE 10TH WARMEST
AUGUST GOING BACK TO 1878.
DAILY AVERAGE TEMPERATURES OF 87.5 ON THE 15TH AND 88.0 ON THE 16TH
WERE THE WARMEST EVER ON THOSE DATES. THE 105 ON THE 16TH SET A NEW
RECORD FOR THE DATE. IT TIES WITH JULY 16TH AND 21ST AS THE HOTTEST
TEMPERATURE THIS SUMMER.
DURING THE FIRST THREE DAYS OF THE MONTH, SOUTHWEST FLOW ALOFT ON
THE NORTHWEST EDGE OF AN UPPER LEVEL HIGH PRESSURE RIDGE BROUGHT
ABOVE NORMAL TEMPERATURES. ON THE 3RD, MONSOON MOISTURE CARRIED
NORTH BY THE FLOW CONTRIBUTED A COUPLE HUNDREDTHS OF AN INCH OF RAIN
DURING A THUNDERSTORM.
ON THE 4TH, A WEAK LOW PRESSURE SYSTEM BROUGHT ADDITIONAL LIGHT
RAIN, PLUS ENOUGH CLOUD COVER TO HOLD AFTERNOON TEMPERATURES IN THE
LOWER 80S. TEMPERATURES CONTINUED BELOW NORMAL THROUGH THE 8TH AS A
SERIES OF WEAK TROUGHS, EMBEDDED IN WESTERLY FLOW ALOFT, CROSSED OUR
AREA FROM THE NORTHWEST COAST. NO SIGNIFICANT RAIN WAS MEASURED, BUT
DURING THE EARLY EVENING OF THE 7TH, A THUNDERSTORM OUTFLOW
GENERATED A GUST OF 52 MPH AT THE AIRPORT.
TEMPERATURES RETURNED TO NORMAL ON THE 9TH UNDER SOUTHWEST FLOW AND
DRIER AIR AHEAD OF THE LAST TROUGH OF THE SERIES.
ON THE 12TH AND 13TH, A STRONG UPPER-LEVEL HIGH PRESSURE RIDGE BUILT
OVER THE NORTHWEST COAST AND PUSHED AS FAR NORTH AS CENTRAL BRITISH
COLUMBIA.
UNDER THE INFLUENCE OF THE RIDGE, PLUS SOUTHERLY FLOW FROM NEVADA,
TEMPERATURES ROSE INTO THE UPPER 90S ON THE 14TH AND THE TRIPLE
DIGITS FROM THE 15TH THROUGH THE 17TH. DURING THAT TIME, HURRICANE
HILARY WAS GATHERING STRENGTH OFF THE SOUTH COAST OF MEXICO, AND BY
THE 19TH, SHE WAS ON HER WAY UP THE WEST COAST OF BAJA CALIFORNIA.
CLOUD COVER SPREADING NORTH FROM HILARY WAS ENOUGH TO COOL HIGHS
INTO THE MID 80S ON THE 19TH, AND A THUNDERSTORM BROUGHT JUST A
TRACE OF RAIN.
THE REMAINS OF HILARY ARRIVED IN SOUTHERN CALIFORNIA ON THE 20TH.
SOUTHERLY FLOW BETWEEN A VAST WARM HIGH PRESSURE RIDGE CENTERED OVER
KANSAS AND A LOW PRESSURE TROUGH OVER THE CALIFORNIA COAST CONTINUED
TO SWEEP HILARY MOISTURE NORTHWARD. SOUTHERLY WINDS GUSTING TO 38
MPH ON THE 20TH AND 42 MPH ON THE 21ST CAUSED BLOWING DUST IN THE
BOISE AREA.
A SHOWER ON THE 21ST SETTLED SOME OF THE DUST AND DROPPED OVER A
THIRD OF AN INCH OF RAIN AT THE AIRPORT. MORE HILARY MOISTURE
ARRIVED ON THE 22ND, AND NEARLY TWO-THIRDS OF AN INCH OF RAIN FELL
DURING A THUNDERSTORM.
UNDER DRIER SOUTHWEST FLOW ALOFT, THREE DAYS PASSED WITH NO
MEASURABLE RAIN.
ON THE 24TH THE FLOW SHIFTED BACK INTO THE SOUTH, AND ON THE 25TH
ENOUGH TROPICAL MOISTURE HAD ARRIVED TO FUEL A THUNDERSTORM. ONLY A
TRACE OF RAIN FELL AT THE AIRPORT.
MORE ABUNDANT MOISTURE FOLLOWED ON THE 26TH. ALTHOUGH THE
THUNDERSTORMS WERE FEW AND FAR BETWEEN, THEY WERE VERY WET. THEY
PERSISTED INTO THE NIGHT, SUPPORTED BY UNSTABLE AIR AND A WEAK
DISTURBANCE IN THE SOUTHERLY FLOW.
SHORTLY AFTER 11 PM MDT ON THE 26TH, AS THUNDERSTORMS APPROACHED
FROM THE SOUTH, ONE STORM FORMED DIRECTLY OVER THE AIRPORT. THE
DELUGE BEGAN, ACCOMPANIED BY PEA-SIZE HAIL AND WINDS GUSTING TO 51
MPH FROM THE SOUTHEAST. A SECOND CELL FOLLOWED. BY THE TIME THE
STORMS PASSED THE AIRPORT ON THEIR WAS TO THE FOOTHILLS, 1.46 INCHES
OF RAIN HAD FALLEN IN UNDER AN HOUR.
THE COMBINATION OF SOUTHWEST FLOW ALOFT AND THE PROXIMITY OF THE
VERY WARM HIGH PRESSURE RIDGE TO OUR SOUTHEAST KEPT HIGHS IN THE MID
TO UPPER 90S THROUGH THE 29TH.
DURING LATE AFTERNOON ON THE 29TH, THE TROUGH WHICH HAD BEEN OFF THE
NORTHWEST COAST FOR SEVERAL DAYS WAS FINALLY KICKED INLAND BY STRONG
WESTERLY FLOW FROM SOUTH OF THE ALEUTIANS. THE HIGH OF ONLY 77 ON
THE 30TH WAS THE FIRST HIGH UNDER 80 DEGREES SINCE THE 73 ON JUNE
25TH.
LOOKING AT BOISE WEATHER BALLOON DATA BACK TO 1948, THIS AUGUST HAS
SEEN THE MOST LAUNCHES WITH 1"+ PRECIPITABLE WATER MEASUREMENTS ON
RECORD. PRECIPITABLE WATER VALUES REPRESENT THE AMOUNT OF WATER IN A
COLUMN OF THE ATMOSPHERE WERE IT TO BE 'WRUNG OUT', MUCH LIKE IT HAS
BEEN WITH RECENT THUNDERSTORMS. IN AN AVERAGE AUGUST WE RECORD 1"+
OF PRECIPITABLE WATER LESS THAN 4 TIMES, AND LESS THAN 12 TIMES IN A
YEAR. THIS AUGUST HAS SEEN 24 BALLOON LAUNCHES MEASURE 1"+ OF
PRECIPITABLE WATER (TOPPING 21 IN 1983) WITH A YEAR TO DATE TOTAL OF
38, WHICH IS ALSO THE MOST ON RECORD (TOPPING 29 IN 1983).
AT THE SURFACE, BOISE RECORDED 60 HOURS WITH A DEW POINT AT OR ABOVE
60 DEGREES. THIS IS THE SECOND MOST HOURS OF 60+ DEGREE DEW POINTS
AT BOISE FOR THE MONTH OF AUGUST, THE MOST BEING 65 HOURS IN 1983.
FOR COMPARISON, BOISE AVERAGES 19 HOURS A YEAR WITH A DEW POINT AT
OR ABOVE 60 DEGREES. SO IF YOU WERE THINKING IT WAS FEELING HUMID
RECENTLY, FOR THESE PARTS IT HAS BEEN.
...............................
..THE BOISE ID CLIMATE SUMMARY FOR SEPTEMBER 1 2023
VALID AS OF 0900 AM LOCAL TIME.
CLIMATE NORMAL PERIOD 1991 TO 2020
CLIMATE RECORD PERIOD 1875 TO 2023
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL LAST
VALUE (LST) VALUE VALUE YEAR
.......................................................
TEMPERATURE (F)
TODAY
MAXIMUM 66 1214 AM 102 1945 86 97
MINIMUM 62 711 AM 39 1892 57 64
AVERAGE 64 71 81
PRECIPITATION (IN)
TODAY 0.00 0.65 1964 0.01 0.00
MONTH TO DATE 0.00 0.01 0.00
SINCE OCT 1 14.29 11.09 10.82
SINCE JAN 1 9.19 7.56 6.28
.......................................................
RELATIVE HUMIDITY (PERCENT)
HIGHEST 60 600 AM
......................................................
THE BOISE ID CLIMATE NORMALS FOR TOMORROW
NORMAL RECORD YEAR
MAXIMUM TEMPERATURE (F) 85 101 1950
2022
MINIMUM TEMPERATURE (F) 57 39 1894
SUNRISE AND SUNSET
SEPTEMBER 1 2023.....SUNRISE 708 AM MDT SUNSET 820 PM MDT
SEPTEMBER 2 2023.....SUNRISE 710 AM MDT SUNSET 819 PM MDT
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
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