Climatological Report (Monthly)
Issued by NWS Juneau, AK

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000
CXAK57 PAJK 160729
CLMAJK
NATIONAL WEATHER SERVICE JUNEAU AK
1121 AM AKST THU JAN 04 2024

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

...THE JUNEAU CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2023...

CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1936 TO 2024

WEATHER         OBSERVED          NORMAL  DEPART   LAST YEAR`S
                VALUE   DATE(S)   VALUE   FROM     VALUE
                                          NORMAL
..............................................................
TEMPERATURE (F)
RECORD
 HIGH             54   12/08/2017
                       12/23/1999
                       12/12/1944
 LOW             -21   12/31/1949
HIGHEST           48   12/30         44       4
LOWEST            23   12/19          5      18
AVG. MAXIMUM    39.5               34.7     4.8
AVG. MINIMUM    32.3               25.9     6.4
MEAN            35.9               30.3     5.6
DAYS MAX >= 90     0                0.0     0.0
DAYS MAX <= 32     0               10.1   -10.1
DAYS MIN <= 32    17               21.1    -4.1
DAYS MIN <= 0      0                0.5    -0.5

PRECIPITATION (INCHES)
RECORD
 MAXIMUM       13.61   1997
 MINIMUM        0.49   1983
TOTALS         10.61               6.53    4.08
DAILY AVG.      0.34               0.21    0.13
DAYS >= .01       25               21.1     3.9
DAYS >= .10       20               13.9     6.1
DAYS >= .50        7                4.2     2.8
DAYS >= 1.00       2                1.2     0.8
GREATEST
 24 HR. TOTAL   2.01   12/14 TO 12/15

SNOWFALL (INCHES)
RECORDS
 TOTAL          54.7
TOTALS          13.2               18.1    -4.9      8.4
SINCE 7/1       19.7               32.8   -13.1
DAYS >= TRACE     18               10.1     7.9       18
DAYS >= 1.0        5                5.0     0.0        2

DEGREE DAYS
HEATING TOTAL    894               1076    -182
 SINCE 7/1      3093               3696    -603
COOLING TOTAL      0                  0       0
 SINCE 1/1         8                  2       6

FREEZE DATES
RECORD
 EARLIEST     08/24/1969
 LATEST       06/13/1965
EARLIEST                        10/21
LATEST                          05/05
..............................................................

WIND (MPH)
AVERAGE WIND SPEED              10.6
HIGHEST WIND SPEED/DIRECTION    47/110    DATE  12/12
HIGHEST GUST SPEED/DIRECTION    65/110    DATE  12/12


WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               1
HEAVY RAIN                0     RAIN                       9
LIGHT RAIN               27     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       3
LIGHT SNOW               19     SLEET                      0
FOG                      28     FOG W/VIS <= 1/4 MILE      2
HAZE                      0

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

$$

While precipitation was generally above normal for Southeast Alaska,
the bigger story was the warmer than normal conditions that all
locations experienced. But in an age of a warming global climate,
this should not be too surprising.

Sitka experienced its 2nd warmest year on record, Juneau its 6th
warmest, Ketchikan its 13th warmest, and Yakutat its 13th warmest
year. To put this into perspective, the shortest of these records is
Sitka and it goes back to 1944. The longest record, Yakutat, goes
back to 1910. There were some notable cold spells across all of
Southeast Alaska; the last week of February through the second week
of March and then again at the end of October. However, when looking
at the daily temperature ranges for each of the 4 climate sites
plotted against the normal daily highs and lows, two things become
obvious. First of all, overnight lows did not get down to or below
normal nearly as often as daytime highs rose to above normal vlaues.
Secondly, the degree to which daily highs were higher than normal
was significantly greater than the degree to which overnight lows
were lower than normal, meaning that the average daily temperatures
were skewed warmer than normal.  Also not surprisingly, daily high
temperature records were set 21 times through the year with at least
one event at each of the climate sites.  Conversely, only 2 record
low temperatures were recorded during the year; once at Juneau and
once at Sitka. Interestingly, as the La Nina winter of 2022-2023
ended, many were expecting to see below normal temperatures for the
season. In fact, only Ketchikan closed out the winter with below
normal temperatures. This was due in large part to a very warm
January across Southeast Alaska.

The beginning of Spring featured heavy snow on the 1st of March and
then again at the middle of the month, but very little after that
time. Precipitation totals for the month were, however, below normal
and the excess snow was a result of colder than normal temperatures.

Temperatures finally trended above normal by May and what followed
was some excellent summer in spite of precipitation remaining above
normal through June. The summer ended in August with a glacially
dammed lake release at Suicide Basin. This release produced an all
time record flooding event on the Mendenhall River. Two homes were
completely destroyed when they fell into the river due to riverbank
erosion and several other structures were condemned due to the river
undercutting their foundations. The fast flowing flood waters
altered the path of the riverbed, dramatically so in some locations.

Fall began with much above normal precipitation from several
atmospheric rivers that impacted the region. Moderate flooding
occured on Jordan Creek near the Juneau airport and Sitka came close
to recording a new precipitation record for the month. A very strong
Autumn storm affected all of Southeast Alaska in the days before
Thanksgving. High winds occured across all of Southeast Alaksa with
snow over the northern half of the Panhandle and rain to the south.
The combination of wind and snow produced blizzard conditions in the
Juneau area. The strong winds and heavy rain also resulted in
tragedy when a deadly landslide struck the community of Wrangell in
a scenario all too similar to the fatal landslide that occured in
Haines in 2020.

By the beginning of the Winter and the end of 2023, a strong El Nino
had developed and this was reflected in monthly average temperatures
from 4 to 6 degrees above normal at the primary climate sites. Not
surprisingly, even though precipitation was once again above normal,
snow totals were below normal.

Fritsch
$$


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