BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, SEPTEMBER 17, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME
 
QUITE CHILLY, BUT NO NEW RECORDS;
CLEAR, DRY, BEAUTIFUL FALL DAY
 
The temperature fell steadily from 64F yesterday evening through sunrise,
with a low temperature bottoming out at 40F (39.9F to be exact).  This was
the coolest temperature recorded on the summit since May 26.  This morning's
low was only 2 degrees off of the record of 38F set in 1959.  The temperature
began warming up quickly after sunrise, reaching 50F shortly after 9 A.M. EDT.
This afternoon's high temperature has only reached 58F, but is several
degrees warmer than the record low maximum temperature for the date of 51F
set in 1954.  Today's average temperature looks to finish nearly 15 degrees
below normal, pushing the average monthly temperature thus far to one
degree below normal.
 
The sky has been mostly clear today, with only a few ocean-effect clouds to
our east mainly this morning and a few very small cumulus forming inland
this afternoon.  Some very high, very thin cirrus has filtered into the
sky early this afternoon.
 
The clean, dry air mass is allowing for crisp visibility of at least
80-85 miles.  The dew point temperature has remained in the mid to upper 30s
today.
 
The sea-level atmospheric pressure is running high today, topping out late
this morning near 1031 mb (30.45 inches).  This is the highest pressure
reading on the summit since May.
 
It is expected to be another chilly day tomorrow, but again not likely to be
cold enough to set new records:
 
Current records for September 18
Low minimum: 36F in 1919
Low maximum: 57F in 1978
 
Today's Observations:
 
7 A.M.  
Weather: Scattered stratocumulus/cumulus, few lower cumulus fractus ENE-ESE,
stratocumulus and a few cumulus NE-E-S, thin smoke layer along horizon
all quadrants
Temperature: 44F; Dew Point: 37F; Wind: NNW at 8 kts,
Wind: Direction variable NW-N
Sea-level pressure: 30.40 ins. Hg, rising
Visibility: 85 miles
24-hr precip: 0.02 inch
6-hr min. temp: 40F
BHO SA 1155 35 SCT 85 293/44/37/3408/040/ FEW LWR CUFRA ENE-ESE SC AND
FEW CU NE-E-S THN K LYR ALG HRZN ALQDS WND 31V01/ 8/500 53027 MANUAL 70002
ASOS 70001 10045 20040
 
10 A.M. 
Weather: Scattered cumulus (2 levels), cumulus mostly NE-SE-SSW, few higher
small cumulus forming all quadrants
Temperature: 54F; Dew Point: 36F; Wind: NNE at 9 kts,
Wind: Direction variable NNW-E
Sea-level pressure: 30.44 ins. Hg, rising
Visibility: 85 miles
BHO SA 1455 35 SCT 40 SCT 85 307/54/36/0209/044/ CU MSTLY NE-SE-SSW FEW
HIER SML CU FRMG ALQDS WND 34V08/ 8/100 51014
 
1 P.M. 
Weather: Scattered thin cirrus (2 levels), few small cumulus distant E-SSW
and distant NW-NNW, lower cirrus SE-SW-W, higher cirrus NE-S-NNW and
overhead
Temperature: 57F; Dew Point: 37F; Wind: NE at 8 kts,
Wind: Direction variable N-E
Sea-level pressure: 30.41 ins. Hg, falling
Visibility: 80 miles
6-hr max. temp: 58F
BHO SA 1755 250 –SCT 300 –BKN 80 299/57/37/0508/041/ FEW SML CU DSNT E-SSW
AND DSNT NW-NNW LWR CI SE-SW-W HIER CI NE-S-NNW AND OVHD WND 01V08/ 8/101
58008 10058 20044
 
WEATHER SUMMARY FOR MONDAY, SEPTEMBER 16, 2013
 
TEMPERATURE (DEGREES F)
MAX.....66     NORMAL.....72
MIN.....46     NORMAL.....55
MEAN....56     NORMAL.....63
 
DEPARTURE FROM 30-YEAR NORMAL......................-7
TOTAL DEPARTURE FOR THE MONTH......................-2 [-0.3 DEGREE/DAY]
 
COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY..............0   DEPARTURE.........-2
TOTAL COOLING UNITS FOR THE MONTH.............54   DEPARTURE.........+9
TOTAL COOLING UNITS FOR THE SEASON...........694   DEPARTURE.......+112
TOTAL COOLING UNITS LAST SEASON TO DATE......764   DIFFERENCE.......-70
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY..................29 NNW AT  9:03 P.M.
                   AERO.......................31 NNW AT  7:38 P.M.
                   ASOS.......................31 NNW AT  9:03 P.M.
                   DAVIS......................27 N   AT  9:03 P.M  RMY 30
FASTEST MILE FOR YESTERDAY....................22 NNW AT  9:04 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE.................21 NNW AT  9:04 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE................18 NNW AT  9:03 P.M.
AVERAGE WIND SPEED AND DIRECTION............10.6 NW
                   ASOS.....................10.0
                   DAVIS.....................9.1 WNW [293 degrees]
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.02   DEPARTURE.............-0.12
                         ASOS..............0.01
TOTAL PRECIPITATION FOR THE MONTH..........3.52   DEPARTURE.............+1.49
                         ASOS..............3.63
TOTAL PRECIPITATION FOR THE YEAR..........41.53   DEPARTURE.............+4.48
                         ASOS..............N/A*
*ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals 
     
PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 2013 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust
RMY:  RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
9/1  76/67/72/+4/2.32/008/01         33 S   AERO 39 MPH S   RMY 38   TSTM
9/2  79/67/73/+5/0.43/056/07         30 SSE AERO 33 MPH SSE RMY N/A  TSTM
9/3  79/61/70/+3/0.00/219/28         28 S   AERO 29 MPH S   RMY 30   TSTM
9/4  78/57/68/+1/0.00/733/94         24 W   AERO 25 MPH W   RMY 25
9/5  66/51/59/-8/0.08/179/23         20 NNE AERO 20 MPH NNE RMY 21
9/6  68/46/57/-10/0.00/751/97        18 WSW AERO 17 MPH WSW RMY N/A
9/7  78/51/65/-1/0.00/594/77         20 WSW AERO 21 MPH WSW RMY 21
9/8  74/50/62/-4/0.00/646/84         31 NW  AERO 33 MPH NW  RMY 32
9/9  69/47/58/-8/T/529/69            23 SW  AERO 23 MPH SSW RMY N/A
9/10 73/56/65/0/0.03/007/01          30 S   AERO 32 MPH S   RMY 33
9/11 93/68/81/+16/0.00/654/86        25 SW  AERO 27 MPH SW  RMY N/A
9/12 85/66/76/+11/0.47/.../..        32 S   AERO 33 MPH S   RMY 34   TSTM
9/13 79/58/69/+5/0.17/.../..         24 NNW AERO 25 MPH NNW RMY 23
9/14 67/52/60/-4/0.00/.../..         21 NW  AERO 21 MPH NW  RMY 21
9/15 70/48/59/-5/0.00/.../..         17 WSW AERO 18 MPH WSW RMY 20
9/16 66/46/56/-7/0.02/.../..         29 NNW AERO 31 MPH NNW RMY 30
 
9/17 morning low temp: 40F; the normal low is now 54F
 
DAILY RECORDS FOR SEPTEMBER 2013
9/1  - NEW DAILY RECORD MAXIMUM PRECIPITATION OF 2.32 INCHES;
       surpasses previous record of 1.60 inches set in 1927
9/11 - TIED DAILY RECORD MAXIMUM HIGH TEMPERATURE OF 93F;
       ties record of 93F set in 1983
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR SEPTEMBER 17
HIGH 86F IN 1915,1941,1991
LOW 38F IN 1959
PRECIP 2.73 INCHES IN 1933
PEAK GUST 60 MPH WNW IN 1999
 
RECORDS FOR SEPTEMBER 18
HIGH 88F IN 1906
LOW 36F IN 1919
PRECIP 4.25 INCHES IN 1996
PEAK GUST 77e MPH WNW IN 1948
 
TODAY'S REPORT PREPARED BY: Sean Fankhauser