Saturday, September 21, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, SEPTEMBER 21, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

WARM WITH INCREASING CLOUDS AND HUMIDITY TODAY…
TODAY IS THE 75TH ANNIVERSARY OF THE GREAT NEW ENGLAND HURRICANE OF 1938…

While the weather remains comfortable today, a change is on the way tonight
and tomorrow as a cold front approaches.  Ahead of the front the dew point
has increased to the upper 50’s with the wind increasing from the S-SSW.
Dense fog shrouded the summit early this morning, though this lifted by
mid-morning, and the visibility has climbed to near 70 miles at mid-day
under a partly sunny sky. The winds continue to increase at early afternoon
with a peak gust so far to 30 mph S recorded at 2:22 PM EDT.

Today marks the 75th anniversary of the Great New England Hurricane of 1938.
The day was warm and humid with a high temperature of 77 degrees. As the
wind increased during the afternoon one wind recorder was destroyed, but
another survived as the storm passed in the late afternoon and recorded a
5-minute average wind on the summit of 121 mph from the south at 6:11 to
6:16 PM. From this, a peak gust was calculated at 186 mph (with an estimated
error of +/- 30 or 40 mph). Other 5-minute average wind speeds to 119 mph
(at 6:01 to 6:06 PM) and 116 mph (at 5:01 to 5:06 PM) were also record.
The center of the tropical cyclone traveled well to the west of the area,
bisecting Long Island before traveling rapidly northward through western CT,
western MA, and western VT.  Consequently, despite the almost unimaginable
wind, only 0.13 inch of rainfall was recorded that afternoon, though a total
of about four inches of rain had fallen in the preceding days. The minimum
sea-level pressure at the Observatory was 29.01 inches at 5:17 PM. A portion
of the hand-written records from this day can be found on bluehill.org in
the member content area.

Today’s Observations:

7 A.M.
Weather: Sky partly obscured in dense fog, overcast stratus, overcast
partly thin, higher clouds occasionally visible, stratus drifting over
summit, sun occasionally dimly visible
Temperature: 59F; Dew Point: 58F; Wind: S at 10 kts
Sea-level pressure: 30.01 ins. Hg, falling then increasing
Visibility: 1/8 mile, variable 1/16 to 1/4 mile
6-hr min. temp: 57F
BHO SA 1155 –X E2 OVC 1/8VF 162/59/58/1810/001/ F5 OVC PRTLY THN HIR CLDS
OCNLY VSBL STRA DRFTG OVR SMT SUN OCNLY DMLY VSBL VSBY 1/16V1/4/ 8/531
55007 10059 20057

10 A.M.
Weather: Scattered stratocumulus, scattered altocumulus, thin scattered
cirrus
Temperature: 69F; Dew Point: 59F; Wind: S at 16G21 kts
Sea-level pressure: 29.98 ins. Hg, rising
Visibility: 70 miles, light distant haze
BHO SA 1455 30 SCT 120 SCT 250 –SCT 70 152/69/59/1916G21/998/ FEW CUFRA
VCNTY STN LGT DSNT HZ/ 8/531 58010

1 P.M.
Weather: Broken stratocumulus (2 layers), broken cirrus, few lower
stratocumulus
Temperature: 71F; Dew Point: 60F; Wind: S at 17G24 kts
Sea-level pressure: 29.91 ins. Hg, falling
Visibility: 70 miles, light distant haze
6-hr max. temp: 72F
BHO SA 1755 E30 BKN 40 BKN 250 BKN 70 128/71/60/1917G24/991/ FEW LWR SC
LGT DSNT HZ/ 8/501 56024 10072 20059

WEATHER SUMMARY FOR FRIDAY, SEPTEMBER 20, 2013

TEMPERATURE (DEGREES F)
MAX…..78    NORMAL…..71
MIN…..54    NORMAL…..53
MEAN….66    NORMAL…..62

DEPARTURE FROM 30-YEAR NORMAL………………….+4
TOTAL DEPARTURE FOR THE MONTH…………………-10 [-0.7 DEGREE/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………..1   DEPARTURE……….0
TOTAL COOLING UNITS FOR THE MONTH………….55   DEPARTURE………+4
TOTAL COOLING UNITS FOR THE SEASON………..695   DEPARTURE…….+107
TOTAL COOLING UNITS LAST SEASON TO DATE……765   DIFFERENCE…….-70

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL COOLING UNITS FOR YESTERDAY…………..0   DEPARTURE………-5
TOTAL COOLING UNITS FOR THE MONTH………….64   DEPARTURE……..+12
TOTAL COOLING UNITS FOR THE SEASON…………76   DEPARTURE………-1
TOTAL COOLING UNITS LAST SEASON TO DATE…….33   DIFFERENCE…….+43

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………18 SSW AT 11:57 P.M. *
AERO…………………..18 SSW AT 11:57 P.M. *
ASOS…………………..20 SSW AT 11:56 P.M.
DAVIS………………….N/A                    RMY 23
FASTEST MILE FOR YESTERDAY………………..16 SSW AT 11:56 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………..16 S   AT 11:57 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….N/A
AVERAGE WIND SPEED AND DIRECTION………….8.3 SSW
ASOS………………….7.2
DAVIS…………………7.0 SW [222 degrees] * last of several occurrences…

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00   DEPARTURE………….-0.14
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….3.52   DEPARTURE………….+0.93
ASOS…………..3.63
TOTAL PRECIPITATION FOR THE YEAR……….41.53   DEPARTURE………….+3.92
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/+11/0.47/455/60        32 S   AERO 33 MPH S   RMY 34   TSTM
9/13 79/58/69/+5/0.17/242/32         24 NNW AERO 25 MPH NNW RMY 23
9/14 67/52/60/-4/0.00/361/48         21 NW  AERO 21 MPH NW  RMY 21
9/15 70/48/59/-5/0.00/547/73         17 WSW AERO 18 MPH WSW RMY 20
9/16 66/46/56/-7/0.02/179/24         29 NNW AERO 31 MPH NNW RMY 30
9/17 60/40/50/-13/0.00/722/97        27 NNE AERO 27 MPH NNE RMY 26
9/18 73/47/60/-2/0.00/726/98         18 W   AERO 18 MPH WSW RMY 20
9/19 78/51/65/+3/0.00/…/..         17 WSW AERO 16 MPH WSW RMY 18
9/20 78/54/66/+4/0.00/…/..         18 SSW AERO 18 MPH SSW RMY 23

9/21 morning low temp: 57F; the normal low is now 53F

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 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: Mike Iacono