Climatological Report (Monthly)
Issued by NWS Portland, ME

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000 CXUS51 KGYX 041418 CLMPWM PWMCLMPWM 000 TTAA00 KGYX 021927 CLIMATE REPORT NATIONAL WEATHER SERVICE GRAY ME 1018 AM EDT WED OCT 4 2017 ................................... ...THE PORTLAND ME CLIMATE SUMMARY FOR THE MONTH OF SEPTEMBER 2017... CLIMATE NORMAL PERIOD 1981 TO 2010 CLIMATE RECORD PERIOD 1941 TO 2017 /FOR TEMPERATURES/ CLIMATE RECORD PERIOD 1871 TO 2017 /FOR PRECIPITATION/ CLIMATE RECORD PERIOD 1882 TO 2017 /FOR SNOWFALL/ WEATHER OBSERVED NORMAL DEPART LAST YEAR`S VALUE DATE(S) VALUE FROM VALUE DATE(S) NORMAL ................................................................ TEMPERATURE (F) RECORD HIGH 95 09/11/1983 09/07/1945 LOW 23 09/30/1941 HIGHEST 86 09/24 86 0 91 09/09 LOWEST 41 09/30 37 4 39 09/26 AVG. MAXIMUM 74.3 70.0 4.3 74.0 AVG. MINIMUM 54.9 50.3 4.6 53.6 MEAN 64.6 60.1 4.5 63.8 DAYS MAX >= 90 0 0.3 -0.3 1 DAYS MAX <= 32 0 0.0 0.0 0 DAYS MIN <= 32 0 0.2 -0.2 0 DAYS MIN <= 0 0 0.0 0.0 0 PRECIPITATION (INCHES) RECORD MAXIMUM 10.84 2008 MINIMUM 0.30 1948 TOTALS 2.23 3.69 -1.46 0.86 DAILY AVG. 0.07 0.12 -0.05 0.03 DAYS >= .01 7 9.2 -2.2 7 DAYS >= .10 3 5.6 -2.6 4 DAYS >= .50 3 2.3 0.7 0 DAYS >= 1.00 0 1.1 -1.1 0 GREATEST 24 HR. TOTAL 0.91 09/03 TO 09/03 SNOWFALL (INCHES) RECORDS TOTAL T 1992 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 DAYS >= 1.0 0 0.0 0.0 GREATEST SNOW DEPTH 0 24 HR TOTAL 0.0 DEGREE_DAYS HEATING TOTAL 68 176 -108 97 SINCE 7/1 101 221 -120 111 COOLING TOTAL 65 30 35 68 SINCE 1/1 429 358 71 553 ................................................................. WIND (MPH) AVERAGE WIND SPEED 6.9 HIGHEST WIND SPEED/DIRECTION 24/140 DATE 09/03 HIGHEST GUST SPEED/DIRECTION 32/080 DATE 09/03 SKY COVER AVERAGE SKY COVER 0.50 AVERAGE RH (PERCENT) 73 WEATHER CONDITIONS. NUMBER OF DAYS WITH THUNDERSTORM 1 HEAVY RAIN 3 RAIN 3 LIGHT RAIN 8 FREEZING RAIN 0 LT FREEZING RAIN 0 HEAVY SNOW 0 SNOW 0 LIGHT SNOW 0 FOG 12 FOG W/VIS <= 1/4 MILE 3 HAZE 2 - INDICATES NEGATIVE NUMBERS. R INDICATES RECORD WAS SET OR TIED. MM INDICATES DATA IS MISSING. T INDICATES TRACE AMOUNT. && SEPTEMBER BEGAN THE WAY AUGUST ENDED, WITH COOL, FALL-LIKE WEATHER INCLUDING NIGHTTIME TEMPERATURES IN THE 40S. THAT WOULD QUICKLY CHANGE, HOWEVER, AS A WARM, HUMID WEATHER PATTERN SET UP FOR MOST OF THE MONTH. PORTLAND WOULD NOT SEE A TEMPERATURE IN THE 40S AGAIN FOR NEARLY 4 WEEKS. AFTER A FEW DAYS OF RAIN INCLUDING NEARLY AN INCH ON THE 3RD, A NEW WEATHER PATTERN BEGAN TO EMERGE. A RIDGE OF HIGH PRESSURE BUILT OVER THE WESTERN ATLANTIC AND THE EASTERN UNITED STATES, ALLOWING WARM, HUMID AIR TO BE CONTINUALLY TRANSPORTED NORTHEASTWARD INTO NEW ENGLAND. THERE WERE SEVERAL TROPICAL STORMS AND HURRICANES THAT TRACKED NORTHWARD NEAR THE EAST COAST ALONG THE WESTERN SIDE OF THE RIDGE, BUT EACH OF THESE STORMS STAYED FAR ENOUGH AWAY TO AVOID ANY RAINFALL IN PORTLAND. ALTHOUGH THERE WERE A FEW COLD FRONTS WHICH MANAGED TO DROP TEMPERATURES BACK CLOSER TO NORMAL LEVELS, THE TREND OF WARM AND HUMID CONDITIONS KEPT RETURNING. THE WARMEST PERIOD WAS FROM THE 23RD THROUGH THE 27TH WHEN PORTLAND SAW 5 STRAIGHT DAYS IN THE 80S. A STRONG COLD FRONT BROUGHT COOLER WEATHER FOR THE LAST TWO DAYS OF THE MONTH, MORE TYPICAL OF WHAT WOULD BE EXPECTED IN FALL. THE AVERAGE TEMPERATURE FOR THE MONTH WAS 64.6 WHICH WAS 4.5 DEGREES ABOVE NORMAL AND THE SECOND WARMEST SEPTEMBER ON RECORD. THE WARMEST SEPTEMBER WAS JUST TWO YEARS AGO WHEN THE AVERAGE TEMPERATURE WAS 65.3 DEGREES IN 2015. THE COOLEST WAS IN 1950 WHEN IT WAS 54.5 DEGREES. OF THE TOP TEN WARMEST SEPTEMBERS, 5 HAVE OCCURRED SINCE 2010 AND 8 SINCE 1999. THE FOLLOWING TABLE LISTS THE WARMEST SEPTEMBERS ON RECORD. WARMEST AVERAGE TEMPERATURE FOR SEPTEMBER (SINCE 1940)... RANK TEMP YEAR 1 65.3 2015 2 64.6 2017 <=== 3 64.1 1961 4 63.8 2016 5 63.6 2005 6 63.4 2010 7 63.3 1999 8 63.1 2002 9 62.9 1983 10 72.8 2011 A TOTAL OF 2.23 INCHES OF RAIN FELL WHICH WAS 1.46 INCHES BELOW NORMAL AND THE 4TH CONSECUTIVE MONTH OF BELOW NORMAL PRECIPITATION IN PORTLAND. NEARLY ALL OF THE RAIN FELL IN THE FIRST WEEK OF THE MONTH, WITH THE HEAVIEST FALLING ON THE 3RD WHEN 0.91 INCHES WAS RECORDED. THE DRIEST SEPTEMBER ON RECORD WAS IN 1948 WHEN ONLY 0.30 INCHES FELL. THE WETTEST WAS IN 2008 WHEN 10.84 INCHES WAS RECORDED. THE FOLLOWING DAILY RECORDS WERE SET OR TIED IN SEPTEMBER 2017... DATE RECORD PREVIOUS 20 65 - WARMEST LOW TEMPERATURE 64 IN 2016 27 84 - WARMEST HIGH TEMPERATURE 84 IN 2014 /TIED/ 27 72 - WARMEST AVERAGE TEMPERATURE 67 IN 2014 AND OTHERS $$ KIMBLE

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