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CXUS51 KGYX 030234
CLSPWM

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TTAA00 GYX 011114

CLIMATE REPORT
NATIONAL WEATHER SERVICE GRAY ME
714 AM EDT FRI SEP 01 2023

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

...THE PORTLAND ME CLIMATE SUMMARY FOR THE SUMMER SEASON, FROM
6/1/2023 TO 8/31/2023...

CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1941 TO 2023 (FOR TEMPERATURES)
CLIMATE RECORD PERIOD: 1871 TO 2023 (FOR PRECIPITATION)
CLIMATE RECORD PERIOD: 1882 TO 2023 (FOR SNOWFALL)

WEATHER         OBSERVED          NORMAL  DEPART   LAST YEAR`S
                VALUE   DATE(S)   VALUE   FROM     VALUE DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH            103   08/02/1975
 LOW              33   08/31/1965
                       06/04/1944
HIGHEST           89   07/12         93      -4       96  08/07
LOWEST            43   06/04         42       1       45  06/06
                                                          06/20
AVG. MAXIMUM    74.4               77.3    -2.9     79.0
AVG. MINIMUM    59.0               58.6     0.4     59.2
MEAN            66.7               68.0    -1.3     69.1
DAYS MAX >= 90     0                4.2    -4.2        7
DAYS MAX <= 32     0                0.0     0.0        0
DAYS MIN <= 32     0                0.0     0.0        0
DAYS MIN <= 0      0                0.0     0.0        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM       22.31   2009
 MINIMUM        4.10   1999
TOTALS         17.23              11.15    6.08     9.53
DAILY AVG.      0.19               0.12    0.07     0.10
DAYS >= .01       46               31.9    14.1       26
DAYS >= .10       26               18.8     7.2       17
DAYS >= .50       12                6.7     5.3        5
DAYS >= 1.00       5                2.6     2.4        3
GREATEST
 24 HR. TOTAL   2.22   07/02 TO 07/03

SNOWFALL (INCHES)
RECORDS
 TOTAL           0.0
TOTALS           0.0                0.0     0.0      0.0
SINCE 7/1        0.0                0.0     0.0      0.0
SNOWDEPTH AVG.     0
DAYS >= TRACE      0                0.0     0.0        0
DAYS >= 1.0        0                0.0     0.0        0
GREATEST
 SNOW DEPTH        0
 24 HR TOTAL     0.0

DEGREE DAYS
HEATING TOTAL    155                115      40       99
 SINCE 7/1        19                 21      -2        1
COOLING TOTAL    336                390     -54      503
 SINCE 1/1       342                401     -59      514
................................................................

WIND (MPH)
AVERAGE WIND SPEED              6.2
HIGHEST WIND SPEED/DIRECTION    28/340    DATE  07/29
HIGHEST GUST SPEED/DIRECTION    36/180    DATE  08/25

SKY COVER
AVERAGE SKY COVER           0.60

AVERAGE RH (PERCENT)     81

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM             17     HEAVY RAIN                16
RAIN                     26     LIGHT RAIN                54
FREEZING RAIN             0     LT FREEZING RAIN           0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                0     FOG                       63
FOG W/VIS <= 1/4 MILE    17     HAZE                      10

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

&&

THE SUMMER OF 2023 WAS WET IN THE PORTLAND AREA. MORE OFTEN THAN NOT
A TROUGH OF LOW PRESSURE WAS IN THE VICINITY OF THE NORTHEAST WHICH
LED TO FREQUENT PRECIPITATION EVENTS. MANY OF THESE PRECIPITATION
EVENTS INVOLVED VERY HEAVY RAIN ACROSS MAINE WITH WFO GYX ISSUING
MORE FLASH FLOOD WARNINGS WITHIN THE FORECAST AREA THAN ANY OTHER
YEAR. WHILE THE PORTLAND AREA DID SEE MULTIPLE HEAVY RAIN EVENTS,
THE BULK OF THESE FLASH FLOODING EVENTS OCCURRED ACROSS THE INTERIOR
OF MAINE AND NEW HAMPSHIRE. AFTER A WARM START TO THE SUMMER,
TEMPERATURES TOOK A TUMBLE WELL BELOW NORMAL WHEN A COLD FRONT
DROPPED SOUTH THROUGH THE REGION ON JUNE 3RD RESULTING IN A RECORD
LOW MAXIMUM TEMPERATURE ON THE 4TH WHEN THE HIGH TEMPERATURE ONLY
REACHED 50 DEGREES. IT WAS ALSO DURING THE BEGINNING OF JUNE WHEN
THE NAO DROPPED INTO NEGATIVE TERRITORY WHILE THE PNA TURNED
POSITIVE. THESE TELECONNECTIONS FAVORED A PATTERN OF UPPER LOWS
LINGERING OVER NEW ENGLAND AS A BLOCKING RIDGE OVER EASTERN CANADA
INHIBITED THE EASTWARD PROGRESSION OF THESE SYSTEMS. THIS PATTERN
RESULTED IN TEMPERATURES RUNNING WELL BELOW NORMAL FOR THE MONTH OF
JUNE ALONG WITH 16 DAYS OF THE MONTH RECORDING MEASURABLE
PRECIPITATION AND 23 DAYS WITH FOG. WHILE THE NAO DID TREND TOWARDS
NEUTRAL DURING THE SECOND HALF OF JUNE THE POSITIVE PNA HELPED TO
MAINTAIN THE UNSETTLED PATTERN THROUGH THE END OF THE MONTH. THE NAO
TURNED SHARPLY NEGATIVE IN EARLY JULY AND STAYED THERE THROUGH THE
MIDDLE OF THE MONTH. THIS CONTINUED THE UNSETTLED PATTERN THROUGH
MUCH OF JULY WITH FRONTAL SYSTEMS OFTEN STALLING OVER THE AREA DUE
TO A DOWNSTREAM BLOCKING RIDGE NEAR LABRADOR CANADA. THE PORTLAND
AREA REMAINED ON THE WARM AND HUMID SIDE OF THESE STALLED FRONTS
RESULTING IN A STRETCH OF ALMOST 23 DAYS WHERE THE DEWPOINT DID NOT
DROP BELOW 60 DEGREES. ALONG WITH THE PROLONGED HUMIDITY, THE LOW
TEMPERATURE IN PORTLAND STAYED ABOVE 60 DEGREES FROM THE END OF JUNE
THROUGH MUCH OF JULY. AT THE END OF JULY THE NAO TRENDED TOWARDS
NEUTRAL ALLOWING FOR FRONTAL SYSTEMS TO SWEEP ACROSS THE AREA. THIS
ALLOWED FOR COOLER AND DRIER AIR TO MOVE INTO THE AREA WITH LOW
TEMPERATURES DIPPING INTO THE 50S THE LAST TWO DAYS OF THE MONTH.
TEMPERATURES AVERAGED ABOVE NORMAL IN JULY, LARGELY DUE TO WARM
NIGHT TIME TEMPERATURES WHILE THE HIGH TEMPERATURE NEVER CLIMBED
INTO THE 90S. IN FACT, THIS WAS THE FIRST SUMMER SINCE 2014 WHEN
PORTLAND DID NOT SEE A HIGH TEMPERATURES OF 90 DEGREES OR GREATER.
SINCE TEMPERATURE RECORDS BEGAN IN 1941 THERE HAS ONLY BEEN NINE
OTHER SUMMERS WHEN THE PORTLAND AREA DID NOT SEE A HIGH TEMPERATURE
OF 90 DEGREES OR GREATER. THE THEME OF FREQUENT PRECIPITATION EVENTS
CONTINUED THROUGH AUGUST. DURING THE FIRST HALF OF AUGUST THE NAO
REMAINED NEGATIVE WHILE THE PNA REMAINED POSITIVE WITH THESE
TELECONNECTIONS FAVORING A TROUGH JUST WEST OF NEW ENGLAND. THE NAO
DID TREND TOWARDS NEUTRAL AT TIMES, WHICH ALLOWED THE TROUGH AXIS TO
SHIFT NEAR OVERHEAD OF THE PORTLAND AREA AND SOMETIMES EAST OF NEW
ENGLAND. THIS EASTWARD SHIFT OF THE TROUGH AXIS ALLOWED FOR COOL AND
DRY HIGH PRESSURE SYSTEMS TO BUILD INTO THE AREA BRINGING PERIODS OF
DRY WEATHER WITH TEMPERATURES TRENDING BELOW NORMAL.

THE AVERAGE TEMPERATURE FOR THE SUMMER WAS 66.7 DEGREES, WHICH WAS
1.3 DEGREES BELOW AVERAGE. THE COOLEST SUMMER ON RECORD WAS IN 1964,
1962, AND 1954 WHEN THE AVERAGE TEMPERATURE WAS 63.7 DEGREES. THE
WARMEST WAS 70.5 DEGREES IN 2020.

A TOTAL OF 17.23 INCHES OF PRECIPITATION FELL, WHICH WAS 6.08 INCHES
ABOVE NORMAL AND THE 7TH WETTEST SUMMER ON RECORD. THE HEAVIEST RAIN
FELL ON JULY 2ND INTO THE 3RD WHEN 2.22 INCHES FELL IN 24 HOURS. THE
WETTEST SUMMER WAS IN 2009 WHEN A TOTAL OF 22.31 INCHES OF
PRECIPITATION FELL. THE DRIEST WAS 4.10 INCHES IN 1999. THE
FOLLOWING TABLE LISTS THE WETTEST SUMMERS ON RECORD AT PORTLAND.

MOST PRECIPITATION IN SUMMER (SINCE 1871)...
RANK  PRECIP  YEAR
1     22.31   2009
2     19.15   2012
3     19.04   1991
4     18.98   2014
5     18.43   1915
6     17.56   1917
7     17.23   2023   <===
8     17.20   2006
9     15.96   1998
10    15.89   1872

THE PORTLAND AREA EXPERIENCED 46 DAYS WITH MEASURABLE PRECIPITATION
DURING THE SUMMER OF 2023. THIS WAS THE SECOND HIGHEST NUMBER OF
DAYS WITH MEASURABLE PRECIPITATION DURING SUMMER AFTER 1938 WHEN
THERE WAS 47 DAYS WITH MEASURABLE PRECIPITATION. THE FOLLOWING TABLE
LISTS THE SUMMERS WITH MOST DAYS OF MEASURABLE PRECIPITATION.

MOST DAYS WITH MEASURABLE PRECIPITATION IN SUMMER (SINCE 1871)...
RANK  DAYS  YEAR
1     47    1938
2     46    2023   <===
3     45    1915
      45    1881
5     44    1931
6     43    1896
7     42    2009
      42    1986
      42    1932
10    41    1928
      41    1898
      41    1887

THE FOLLOWING DAILY RECORDS WERE SET OR TIED IN SUMMER 2023...
DATE    RECORD                                 PREVIOUS
JUN  4   50   - LOWEST MAXIMUM TEMPERATURE      51 IN 2018
JUL  2  1.80   - GREATEST PRECIPITATION       1.41 IN 2009
JUL 10    2    - LOWEST TEMPERATURE RANGE        4 IN 1952

$$

DS