Climatological Report (Seasonal)
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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000 CXUS51 KGYX 030234 CLSPWM PWMCLSPWM 000 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