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000
CXUS55 KRIW 022025
CLMP60

CLIMATE REPORT
NATIONAL WEATHER SERVICE RIVERTON WY
225 PM MDT MON OCT 2 2018

...PRELIMINARY MONTHLY CLIMATE SUMMARY FOR LAKE YELLOWSTONE FOR THE
MONTH OF SEPTEMBER 2018...

...OFFICIAL CLIMATE DATA FOR THE MONTH OF SEPTEMBER 2018 WILL BE
AVAILABLE APPROXIMATELY IN 60 DAYS FROM THE NATIONAL CENTERS FOR
ENVIRONMENTAL INFORMATION (HTTP://WWW.NCDC.NOAA.GOV/CDO-
WEB/DATASETS). UNOFFICIAL ASOS DAILY SUMMARIES ARE AVAILABLE ON THE
INTERNET AT HTTP://WWW.WEATHER.GOV/CLIMATE/INDEX.PHP?WFO=RIW

...SEPTEMBER WAS MUCH DRIER THAN NORMAL FOR LAKE YELLOWSTONE...

THE AVERAGE TEMPERATURE FOR LAKE YELLOWSTONE IN AUGUST WAS 46.4
DEGREES...WHICH WAS 0.4 DEGREES BELOW NORMAL. THE WARMEST READING
OF THE MONTH WAS 73 DEGREES ON THE 5TH AND 15TH. THE COLDEST
READING FOR AUGUST WAS 20 DEGREES ON THE 25TH AND 26TH. THIS TIED
THE DAILY RECORD ON THE 25TH PREVIOUSLY SET IN 2000 AND BROKE THE
RECORD ON THE 26TH OF 22 DEGREES ALSO SET IN 2000.

TOTAL PRECIPITATION FOR THE MONTH WAS 0.21 INCHES...WHICH WAS ONLY
16 PERCENT OF NORMAL.  THIS MADE IT THE DRIEST SEPTEMBER ON RECORD
SINCE OFFICIAL RECORDS BEGAN IN 1998. THE WETTEST 24 HOUR PERIOD OF
THE MONTH WAS THE 20TH WHEN 0.09 INCHES FELL. NO PRECIPITATION
RECORDS WERE SET DURING THE MONTH.
THE HIGHEST WIND GUST FOR THE MONTH WAS 31 MPH ON THE 15TH.

...THE LAKE YELLOWSTONE WY CLIMATE SUMMARY FOR THE MONTH OF
SEPTEMBER 2018...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1998 TO 2018

WEATHER         OBSERVED          NORMAL  DEPART
                 VALUE   DATE(S)  VALUE   FROM
                                          NORMAL
................................................
TEMPERATURE (F)
RECORD
 HIGH              79   09/03/2017
                        09/02/2017
                        09/02/2007
 LOW               13   09/24/2000
HIGHEST            73   09/15
                        09/05
LOWEST             20   09/26
                        09/25
AVG. MAXIMUM     63.6
AVG. MINIMUM     29.1
MEAN             46.4              46.8    -0.4
DAYS MAX >= 90      0
DAYS MAX <= 32      0
DAYS MIN <= 32     24
DAYS MIN <= 0       0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         4.09   2013
 MINIMUM         0.25   2008
TOTALS           0.21R             1.30   -1.09
DAILY AVG.       0.01
DAYS >= .01         5
DAYS >= .10         0
DAYS >= .50         0
DAYS >= 1.00        0
GREATEST
 24 HR. TOTAL    0.09   09/20 TO 09/20

DEGREE_DAYS
HEATING TOTAL     554               548       6
 SINCE 7/1       1150              1135      15
COOLING TOTAL       0                 0       0
 SINCE 1/1          0                 0       0
.................................................

WIND (MPH)
AVERAGE WIND SPEED              2.9
HIGHEST WIND SPEED/DIRECTION    18/270    DATE  09/15
HIGHEST GUST SPEED/DIRECTION    31/270    DATE  09/15

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.00
NUMBER OF DAYS FAIR           30
NUMBER OF DAYS PC              0
NUMBER OF DAYS CLOUDY          0

AVERAGE RH (PERCENT)     53

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP                0
HEAVY RAIN                0     RAIN                        2
LIGHT RAIN                3     FREEZING RAIN               0
LT FREEZING RAIN          0     HAIL                        0
HEAVY SNOW                0     SNOW                        0
LIGHT SNOW                0     SLEET                       0
FOG                       0     FOG W/VIS <= 1/4 MILE       0
HAZE                      0

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

LOOKING AHEAD TO OCTOBER 2018...THE AVERAGE HIGH TEMPERATURE ON THE
FIRST OF THE MONTH IS 55 DEGREES...AND THE AVERAGE LOW TEMPERATURE
IS 27. THE AVERAGE HIGH TEMPERATURE BY THE END OF THE MONTH IS 41
DEGREES...AND THE AVERAGE LOW TEMPERATURE IS 19. THE AVERAGE MONTHLY
PRECIPITATION IS 1.35 INCHES.

$$