928
CXAK57 PAJK 042029
CLMASI
NATIONAL WEATHER SERVICE JUNEAU AK
1121 AM AKST THU JAN 04 2024

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

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

CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1944 TO 2024

WEATHER         OBSERVED          NORMAL  DEPART   LAST YEAR`S
                VALUE   DATE(S)   VALUE   FROM     VALUE
                                          NORMAL
..............................................................
TEMPERATURE (F)
RECORD
 HIGH             65   12/12/1944
 LOW              16   12/25/2021
HIGHEST           53   12/29         50       3
LOWEST            31   12/18         19      12
                       12/19
                       12/27
AVG. MAXIMUM    45.8               41.5     4.3
AVG. MINIMUM    37.7               33.4     4.3
MEAN            41.7               37.5     4.2
DAYS MAX >= 90     0                0.0     0.0
DAYS MAX <= 32     0                1.8    -1.8
DAYS MIN <= 32     4               12.4    -8.4
DAYS MIN <= 0      0                0.0     0.0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM       16.55   1956
 MINIMUM        2.25   1983
TOTALS         15.28               8.43    6.85
DAILY AVG.      0.49               0.27    0.22
DAYS >= .01       26               21.6     4.4
DAYS >= .10       24               16.1     7.9
DAYS >= .50       10                5.7     4.3
DAYS >= 1.00       4                1.9     2.1
GREATEST
 24 HR. TOTAL   3.03   12/12 TO 12/12


DEGREE DAYS
HEATING TOTAL    712                854    -142
 SINCE 7/1      2392               3038    -646
COOLING TOTAL      0                  0       0
 SINCE 1/1         4                  1       3

FREEZE DATES
EARLIEST                        10/08
LATEST                          03/14
..............................................................

WIND (MPH)
AVERAGE WIND SPEED              11.7
HIGHEST WIND SPEED/DIRECTION    43/160    DATE  12/12
HIGHEST GUST SPEED/DIRECTION    63/180    DATE  12/12


WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               2
HEAVY RAIN                1     RAIN                      18
LIGHT RAIN               29     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       1
LIGHT SNOW                8     SLEET                      4
FOG                      17     FOG W/VIS <= 1/4 MILE      0
HAZE                      8

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

$$

...ABOVE NORMAL TEMPERATURES AT THE START OF AN EL NINO WINTER...

Multiple record high temperatures during the month were completely
congruent with a strong El Nino. In fact, Juneau finished the month
nearly 6 degrees above normal for daily average temperatures and a
full 6 inches below normal for snowfall. The remaining climate sites
in Southeast Alaska also recorded 4 to 5 degrees above normal for
their daily average temps. Unfortunately, there is no longer
snowfall information for those locations, but it sure would be nice
to know how they measured when compared to their climate normal
values. While there was a dearth of snow for most of Southeast
Alaska, Skagway and Haines and the associated highways got quite a
bit of it. 4 separate winter storm warnings were issued for these
locations with all of them verifying. One event even included an
avalanche near Klukwan that was captured in a photograph.

A quick glance at the daily data for all 4 climate sites indicates
that the above normal monthly temps was more a result of daytime
highs rather than overnight lows. This departs from the typical
trend we have observed for many months where overnight lows were
more responsible for the warmer than normal temperatures.

In keeping with the trend from this Autumn, all 4 sites finished the
month with significantly above normal precipitation and Sitka nearly
achieving record precipitation for December. There is an established
and well studied connection between above normal normal temperatures
and the strong El Nino. Recent studies are hinting at a similar
relationship regarding precipitation too.

The month also saw a series of strong Autumn storms which, in
addition to producing heavy rain, resulted in high winds across much
of the Panhandle and northeast gulf coast. At various times during
the month, high wind warnings were issued for Yakutat, Skagway,
Juneau, Sitka, Prince of Wales Island, Ketchikan, and Metlakatla.

Fritsch
$$