Monday, September 21, 2015

BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, SEPTEMBER 21, 2015
ALL TIMES ARE IN EASTERN STANDARD TIME

COOL FALL-LIKE AIRMASS IS FINALLY HERE AFTER VERY WARM MONTH
TEMPERATURES FALL THROUGH 50’S (55F MIDNIGHT) TO 50F THIS MORNING
COOLEST MINIMUM TEMPERATURE READING SINCE JUNE 29TH ALSO 50F

A large sprawling high pressure system is still arriving with
with rising barometers and temperatures rising from a low of
50F (2 degrees below normal for a change) to the low 60’s along
with gusty NE winds and dew points in the mid-40’s later this
morning.

Today’s Observations:

7 A.M.
Weather: Thin scattered cirrus (2 levels), few cumulus fractus and cumulus
mostly distant ENE-ESE, few stratocumulus distant SE
Temperature: 55F; Dew Point: 47F; Wind: NNE at 10 kts,
Wind: Direction variable NNW-ENE
Sea-level pressure: 30.22 ins. Hg, rising steadily then more rapidly
Visibility: 80 miles
6-hr Max temp: 55F
6-hr Min temp: 50F
24-hr precip: none
BHO SA 1155 250 –SCT 300 –SCT 80 233/55/47/0210/022/ FEW CUFRA/CU MSTLY DSNT
ENE-ESE FEW SC DSNT SE WND 34V06/ 8/801 53016 10055 20050

10 A.M.
Weather: Thin scattered cirrus, thin broken cirrus, lower cirrus
layer S-W advancing
Temperature: 62F; Dew Point 47F; Wind: NE at 10G23 kts,
Wind: Direction variable N-E
Sea-level pressure: 30.28 ins. Hg, rising, then more slowly
Visibility: 75 miles, light distant haze
BHO SA 1455 250 -SCT 300 -BKN 75 253/62/47/0410G23/028/
SML CU ALQDS LWR CI S-W ADVCNG LGT DSNT HZ WND 01V08/ 8/105 51020

1 P.M.
Weather: Scattered dense cirrus, thin scattered cirrus two levels
Temperature: 63F; Dew Point: 47F; Wind: NE 14 kts.
Direction variable NNE-E, gust to 20 kts past hour
Sea-level pressure: 30.27 ins. Hg, falling slightly
Visibility: 80 miles
6-hr Max: 64F
6-hr Min: 55F
BHO SA 1755 220 SCT 250 -SCT 300 -SCT 80 250/63/47/0514/027/ LWR CI AT 220
MSTLY S-W-N WND 02V08 GST 20 KTS PST HR/ 8/002 58003 10064 20055

SUMMARY FOR SUNDAY, SEPTEMBER 20, 2015

TEMPERATURE (DEGREES F)
MAX…..74   NORMAL…..70
MIN…..55   NORMAL…..53
MEAN….65   NORMAL…..62

DEPARTURE FROM 30-YEAR NORMAL……………………+3
TOTAL DEPARTURE FOR THE MONTH………………….+125  [+6.1 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….-1
TOTAL COOLING UNITS FOR THE MONTH………….131   DEPARTURE………+80
TOTAL COOLING UNITS FOR THE SEASON…………797   DEPARTURE……..+209
TOTAL COOLING UNITS LAST SEASON TO DATE…….565   DIFFERENCE…….+232

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….23  S   AT 2:16 A.M.
ASOS……………………25  S   AT 2:16 A.M.
DAVIS…………………..22  SW  AT 12:09 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY……………….. 18  SSW AT 3:01 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………18  SSW AT 3:01 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..17  SSW AT 2:04 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..11.5
ASOS…………………..11.6
DAVIS………………….10.4 NW [310 DEG]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…..trace DEPARTURE…..-0.14
ASOS……………0.00
TOTAL PRECIPITATION FOR THE MONTH………..1.35  DEPARTURE…..-1.23
ASOS……………1.33
TOTAL PRECIPITATION FOR THE YEAR………..31.60  DEPARTURE…..-5.99
ASOS…………….N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY GUST
RMY:  R.M. Young wind gust recording system
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized

9/1  81/65/73/+5/0.00/766/97               20 SSW RMY 20
9/2  89/64/77/+9/0.00/732/93               20 SW  RMY 21
9/3  85/66/76/+9/T/612/78                  17 E   RMY N/A TSTM
9/4  72/58/65/0/0.00/297/38                31 ENE RMY N/A
9/5  77/55/66/-1/0.00/748/96               14 SW  RMY 18
9/6  87/57/72/+5/0.00/753/97               21 SSW RMY 22
9/7  92/63/78/+12/0.00/727/94              23 WSW RMY 24
9/8  97/70/84/+18/0.00/693/90              22 WSW RMY 24
9/9  92/70/81/+15/0.00/683/89              30 SSW RMY 33
9/10 73/62/68/+3/…./000/00               29 NE  RMY N/A
9/11 70/59/65/0/…./084/11                33 NE  RMY N/A
9/12 75/58/67/2/…./380/50                18 SSE RMY 25
9/13 66/60/63/-1/…./000/00               25 E   RMY N/A
9/14 70/53/62/-2/0.00/550/73               33 W   RMY 35
9/15 82/56/69/+5/0.00/736/98               23 W   RMY N/A
9/16 84/62/73/+10/0.00/711/95              17 NW  RMY N/A
9/17 87/64/76/+13/0.00/723/97              17 SW  RMY 16
9/18 86/64/75/+13/0.00/712/96              21 SSW RMY 21
9/19 80/62/71/+9/0.00/…/..               22 S   RMY N/A
9/20 74/55/65/+3/T/…./…                24 S   RMY N/A

9/21 low since midnight is 50F; normal low is now 53F

DAILY RECORDS FOR SEPTEMBER 2015

**9/7 DAILY RECORD MAXIMUM TEMPERATURE OF 92F
TIES PREVIOUS RECORD SET IN 2007**

**9/8 DAILY RECORD MAXIMUM TEMPERATURE OF 97F
BREAKS PREVIOUS RECORD OF 93F SET IN 2007**

**9/8 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F
BREAKS PREVIOUS RECORD OF 69F SET IN 1999**

**9/9 DAILY RECORD MAXIMUM TEMPERATURE OF 92F
BREAKS PREVIOUS RECORD OF 91F SET IN 2002**

**9/9 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F
BREAKS PREVIOUS RECORD OF 69F SET IN 1999**

**9/17 DAILY RECORD MAXIMUM TEMPERATURE OF 87F
BREAKS PREVIOUS RECORD OF 86F SET IN 1915, 1941, AND 1991**

**9/18 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 64F
TIES PREVIOUS RECORD SET IN 1992**

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):

RECORDS FOR SEPTEMBER 21
HIGH 91 IN 1895
LOW 35 IN 1929, 1956, 1962
PRECIP 5.58 INS IN 1961 (HURRICANE ESTHER; RETURNED AS TS SEPT 25-26TH)
PEAK GUST 186 MPH S IN 1938 (GREAT NEW ENGLAND HURRICANE; CALCULATED GUST,
STATION RECORD)

RECORDS FOR SEPTEMBER 22
HIGH 90F IN 1895, 1914
LOW 30F IN 1904 (Earliest freeze)
PRECIP 1.16 INCHES IN 2001
PEAK GUST 60 MPH SSW IN 1989

TODAY’S REPORT PREPARED BY: Robert Skilling