September 2021 Climate Summary for Northern and Eastern Maine

...SEPTEMBER 2021 CLIMATE NARRATIVE FOR NORTHERN/EASTERN MAINE...

SEPTEMBER 2021 FOR NORTHERN AND EASTERN MAINE FINISHED WITH ABOVE

NORMAL TEMPERATURES AND MUCH ABOVE NORMAL RAINFALL.

AVERAGE TEMPERATURES FOR THE MONTH MOSTLY RANGED FROM 1.5 TO

2.5 DEGREES F ABOVE THE 1991-2020 MEANS. MOST SEPTEMBER MEAN

TEMPERATURES FOR OUR CLIMATE SITES ARE TIGHTLY CLUSTERED AROUND

THEIR AVERAGES OVER THE LENGTH OF RECORD FOR EACH SITE.

SUBSEQUENTLY, THESE RELATIVELY MODEST TEMPERATURE DEPARTURES

PLACED MOST OF OUR CLIMATE LOCATIONS WITHIN THE TOP 10 WARMEST

SEPTEMBERS. THE FOLLOWING ARE THE RANKINGS THIS MONTH FOR EACH

LOCATION: CARIBOU WITH 58.5 DEGREES...7TH WARMEST, BANGOR WITH

62.3 DEGREES...13TH WARMEST, HOULTON WITH 58.6 DEGREES...5TH

WARMEST, AND MILLINOCKET WITH 60.3 DEGREES...7TH WARMEST. THESE

COMPARE TO THE WARMEST SEPTEMBER AVERAGE TEMPERATURE YEARS AS

FOLLOWS: CARIBOU 61.7 IN 1999, BANGOR 65.6 IN 1934, HOULTON 62.4

IN 1999, AND MILLINOCKET 64.1 IN 2015.

THE MONTH BEGAN WITH THE FIRST FEW AND ENDED WITH THE LAST FEW

DAYS ON A COOL NOTE WITH MOST OF THE REST OF THE MONTH AT TO

ABOVE NORMAL. THE WARMEST DAILY DEPARTURES FROM NORMAL OF +10 TO

+15 DEGREES F OCCURRED BETWEEN THE 22ND AND 25TH. OTHERWISE, NO

VERY WARM DAILY HIGH TEMPERATURES WERE RECORDED THIS SEPTEMBER

WITH THE WARMEST HIGHS RECORDED ON THE 18TH AND 23RD WITH BANGOR

THE ONLY CLIMATE SITE ECLIPSING 80 DEGREES. INCREASED CLOUD COVER

AND RAINFALL RESULTED IN WARMER OVERNIGHT LOWS, WITH ONLY THE

MORNING OF 26TH FEATURING LOWS IN THE 30S ACROSS THE NORTH WITH

PATCHY TO AREAS OF FROST.

RAINFALL MOSTLY RANGED FROM 150 TO 250 PERCENT OF AVERAGE ACROSS

THE REGION. THE FOLLOWING ARE RANKINGS FOR OUR CLIMATE SITES FOR

THIS SEPTEMBER: CARIBOU WITH 6.13 INCHES...7TH WETTEST, BANGOR

WITH 9.42 INCHES...2ND WETTEST, HOULTON WITH 7.57 INCHES...4TH

WETTEST, AND MILLINOCKET WITH 7.28 INCHES...9TH WETTEST. THESE

COMPARE TO THE WETTEST SEPTEMBERS OF RECORD FOR EACH LOCATION AS

FOLLOWS: CARIBOU 8.81 INCHES IN 1999, BANGOR 9,88 INCHES IN 1999,

HOULTON 10.20 INCHES IN 2015, AND MILLINOCKET 10.69 INCHES IN

1932.

SOMEWHAT SIMILAR TO SEPTEMBER 1999 AND LAST SEPTEMBER, PRIOR

SUMMER DROUGHT LIKE CONDITIONS ACROSS THE REGION WERE GREATLY

LESSENED BY SEVERAL HEAVY RAINFALLS ASSOCIATED WITH FRONTAL

SYSTEMS WITH TROPICAL MOISTURE. HEAVY RAIN DAYS THAT AFFECTED ALL

OR PARTS OF THE REGION OCCURRED ON THE 2ND-3RD, 9TH-10TH, AND

24TH-26TH WITH MAXIMUM RAINFALLS IN EXCESS OF 4 INCHES AT MANY

LOCATIONS WITH THE 9TH-10TH AND 24-26TH EVENTS. WITH MUCH MORE IN

THE WAY OF BOTH CLOUD COVER AND RAINFALL IN ADDITION TO COOLER

TEMPERATURES AND SHORTER DAYS, TOTAL MONTHLY EVAPORATION AS

MEASURED AT CARIBOU WAS REDUCED TO 2.25 INCHES, WHICH IS ABOUT

HALF THE TOTAL EVAPORATION OBSERVED LAST MONTH.

THE CLIMATE PREDICTION CENTER`S PREDICTION FOR OCTOBER FOR OUR

REGION IS CALLING FOR INCREASED ODDS OF ABOVE NORMAL TEMPERATURES

OVER NEAR AND ESPECIALLY BELOW NORMAL TEMPERATURE CATEGORIES AND

SIGNIFICANTLY INCREASED ODDS OF BELOW NORMAL PRECIPITATION OVER

NEAR AND ESPECIALLY ABOVE AVERAGE PRECIPITATION CATEGORIES.

AVERAGE TEMPERATURES FOR THE 1991-2020 THIRTY YEAR PERIOD ACROSS

NORTHERN/EASTERN MAINE FOR OCTOBER RANGE FROM LOWS OF LOWER TO MID

30S (UPPER 30S TO AROUND 40) TO HIGHS OF LOWER 50S (UPPER 50S)

FOR NORTHERN (DOWNEAST AREAS). TOTAL AVERAGE PRECIPITATION FOR THE

MONTH GENERALLY RANGES FROM 4.00 TO 4.50 INCHES FOR THE SAME 30

YEAR PERIOD.

$$

VJN/CB