Climatological Report (Monthly)
Issued by NWS Boise, ID

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
000
CXUS55 KBOI 011749
CLMBOI

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOISE ID
1149 AM MDT FRI SEP 1 2017

...................................

AUGUST 2017 WAS THE 6TH WARMEST AT THE AIRPORT AND THE 8TH WARMEST
AT ALL OFFICIAL OBSERVING LOCATIONS GOING BACK TO 1875. A PERSISTENT
VERY WARM UPPER-LEVEL HIGH PRESSURE RIDGE, WHICH BUILT OVER THE
INTERMOUNTAIN REGION IN LATE JUNE, WAS RESPONSIBLE FOR THE HOT
WEATHER. WITH THE RIDGE CAME MONSOON MOISTURE.

THE ONLY RECORD HIGH WAS THE 99 ON THE 29TH, WHICH BROKE THE 98-
DEGREE RECORD SET IN 1998 AND EARLIER YEARS.

THE HIGH FOR THE MONTH OF 102 ON THE 2ND WAS NOT A RECORD, BUT IT
WAS THE ONLY TRIPLE-DIGIT HIGH.

A RUN OF 44 CONSECUTIVE DAYS WITH 90-PLUS HIGHS, WHICH BEGAN ON THE
LAST DAY OF JUNE, ENDED ON AUGUST 12. THIS TIED THE 44-DAY STREAK
WHICH ENDED ON AUGUST 20,1994. THE LONGEST PERIOD WAS 50 DAYS WHICH
ENDED ON AUGUST 22, 1875.

A TEMPORARY RESPITE FROM THE HEAT CAME ON THE 13TH, WHEN AN UPPER-
LEVEL LOW PRESSURE TROUGH FROM THE GULF OF ALASKA BROUGHT MUCH
COOLER AIR AND LIGHT RAIN, LOWERING HIGHS BY 15 TO 20 DEGREES. THE
14TH WAS THE COOLEST DAY OF THE MONTH, WITH A HIGH OF ONLY 79, 12
DEGREES BELOW NORMAL FOR THAT DATE.

A SECOND GULF-OF-ALASKA TROUGH PUSHED INLAND OVER WESTERN CANADA ON
THE 18TH AND 19TH. COOLER AIR DRIFTING SOUTH OF THE CANADIAN BORDER
KEPT TEMPERATURES BELOW 90 FROM THE 19TH THROUGH THE 21ST.

THE RIDGE BEGAN TO REBUILD OVER THE WESTERN STATES ON THE 22ND, AND
HIGHS IN THE BOISE AREA WARMED INTO THE LOWER 90S FROM THE 22ND
THROUGH THE 25TH. STARTING ON THE 26TH, THE RIDGE INTENSIFIED, AND
BOISE`S HIGHS CLIMBED INTO THE UPPER 90S FROM THE 26TH THROUGH THE
30TH.

ALTHOUGH DRY COMPARED TO PRECIPITATION AVERAGES FOR THE COOLER
MONTHS, THIS YEAR`S AUGUST AIRPORT TOTAL TIED FOR 29TH PLACE,
ACTUALLY MAKING IT ONE OF THE WETTER AUGUSTS IN THE 78 YEARS OF
AIRPORT RECORDS.

DURING THE AFTERNOON OF THE 24TH, A ROGUE THUNDERSTORM INTENSIFIED
OVER THE OWYHEE MOUNTAINS AND CROSSED THE BOISE AREA THAT EVENING.
ONLY .14 INCH WAS MEASURED AT THE AIRPORT, BUT A TRAINED SPOTTER 4
MILES NORTH-NORTHWEST OF BOISE MEASURED .42 INCH, WITH .35 INCH
FALLING IN LESS THAN 20 MINUTES. THE STORM SPAWNED A WIND GUST OF 58
MPH AT THE AIRPORT AT 7:41 PM MDT.

LATE IN THE AFTERNOON OF THE 30TH, A LINE OF THUNDERSTORMS DESCENDED
INTO THE VALLEY FROM THE OWYHEE MOUNTAINS. A STRONG OUTFLOW WIND
FROM ONE STORM CROSSED THE BOISE AREA FROM THE SOUTHEAST. A SENSOR
AT THE EAST END OF THE AIRPORT MEASURED A GUST OF 67 MPH AT 4:48 PM
MDT.

A PACIFIC COLD FRONT FOLLOWED THE THUNDERSTORMS, PUSHING THE MONSOON
AIR OUT OF SOUTHWEST IDAHO AND BRINGING SLIGHTLY LOWER TEMPERATURES
ON THE 31ST.


...THE BOISE ID CLIMATE SUMMARY FOR THE MONTH OF AUGUST 2017...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1875 TO 2017

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE
                                          NORMAL
.............................................................
TEMPERATURE (F)
HIGHEST           102   08/02
LOWEST             54   08/20
AVG. MAXIMUM     92.6              89.7     2.9
AVG. MINIMUM     63.3              59.6     3.7
MEAN             78.0              74.7     3.3
DAYS MAX >= 90     22
DAYS MAX <= 32      0
DAYS MIN <= 32      0
DAYS MIN <= 0       0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         2.37   1968
TOTALS           0.22              0.24   -0.02
DAYS >= .01         2
DAYS >= .10         1
DAYS >= .50         0
DAYS >= 1.00        0
GREATEST
 24 HR. TOTAL    0.14   08/24 TO 08/24

DEGREE_DAYS
HEATING TOTAL       0                10     -10        0
 SINCE 7/1          0                18     -18
COOLING TOTAL     412               309     103      320
 SINCE 1/1       1166               834     332
..............................................................

WIND (MPH)
AVERAGE WIND SPEED              6.6
RESULTANT WIND SPEED/DIRECTION   1/148
HIGHEST WIND SPEED/DIRECTION    41/240    DATE  08/24
HIGHEST GUST SPEED/DIRECTION    57/250    DATE  08/24

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM

AVERAGE RH (PERCENT)     33


-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.