Sunday, September 29, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, SEPTEMBER 29, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

EARLY DENSE FOG DISSIPATES BY LATE MORNING
FAIR WEATHER CUMULUS LINGER THROUGHOUT THE DAY

The summit was socked in this morning, with dense fog limiting visibility to
1/4 mile in any direction. The ceiling of the fog layer was approximately
800 feet, allowing a view of blue sky and sun above. Some of the fog
condensed in the standing precipitation gauge, and this was not counted
as precipitation.

The fog lifted by 10 A.M revealing ragged cumulus humilis and fractus,
which themselves diminished as the afternoon grew longer. Humidity dropped
sharply and temperatures rose to the mid 60s by early afternoon.

Today’s Observations:

7 A.M.
Weather: Sun and blue sky visible through dense fog
Temperature: 52F; Dew Point: 52F; Wind: NE at 7 kts.
Sea-level pressure: 30.24 ins. Hg, steady
Visibility: 1/4 mile, dense fog
6-hr max. temp: 54F
6-hr min. temp: 51F
Overnight precip: None
BHO SA 1155 E10 BKN 1/4F+ 239/52/52/0507/024/ SUN AND SKY VSBL THRU DNS F/
8//// 50000 10054 20051

10 A.M.
Weather: Scattered ragged cumulus humilis and fractus in the vicinity and
distant all quadrants
Temperature: 61F; Dew Point: 49F; Wind: NE at 8 kts,
Wind: Direction variable N-ESE
Sea-level pressure: 30.24 ins. Hg, increasing then decreasing
Visibility: 50 miles, light distant haze
Visibility: 40 miles SW-N, light distant fog visible
BHO SA 1455 30 SCT 50 240/61/49/0508/024/ SCT CU/CUFRA DSNT ALQDS
LT F DSNT SW-N VSBY 40 SW-N 50 N-E-SW WND VBL N-ESE/ 8/100 50001

1 P.M.
Weather: Clear, few cumulus S-W, scattered cumulus fractus distant
all quadrants, scattered cirrus distant SE-SW
Temperature: 64F; Dew Point: 48F; Wind: ENE at 8 kts,
Wind: Direction variable N-E
Sea-level pressure: 30.19 ins. Hg, decreasing then decreasing more slowly
Visibility: 75 miles, light distant haze
6-hr max. temp: 64F
BHO SA 1755 CLR 75 224/64/48/0608/019/ FEW CU S-W SCT CUFRA DSNT ALQDS
SCT CI DSNT SE-SW LT DSNT HZ WND VBL N-E/ 8/101 56016 10064 20052

WEATHER SUMMARY FOR SATURDAY, SEPTEMBER 28, 2013

TEMPERATURE (DEGREES F)
MAX…..70    NORMAL…..67
MIN…..52    NORMAL…..50
MEAN….61    NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL…………………+3
TOTAL DEPARTURE FOR THE MONTH………………..-24 [-0.9 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………..0   DEPARTURE………-1
TOTAL COOLING UNITS FOR THE MONTH………….56   DEPARTURE………-3
TOTAL COOLING UNITS FOR THE SEASON………..696   DEPARTURE…….+102
TOTAL COOLING UNITS LAST SEASON TO DATE……765   DIFFERENCE…….-69

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..4   DEPARTURE………-3
TOTAL HEATING UNITS FOR THE MONTH…………121   DEPARTURE……..+20
TOTAL HEATING UNITS FOR THE SEASON………..133   DEPARTURE………+7
TOTAL HEATING UNITS LAST SEASON TO DATE…….77   DIFFERENCE…….+56

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………16 NNE AT  8:25 A.M.
AERO…………………..15 NNE AT  8:24 A.M.
ASOS…………………..16 NE  AT  8:35 A.M.
DAVIS………………….15 NNE AT  8:23 A.M.  RMY 15
FASTEST MILE FOR YESTERDAY………………..13 N   AT  3:14 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………..14 N   AT  3:24 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….12 N   AT  3:47 A.M.
AVERAGE WIND SPEED AND DIRECTION………….8.3 N
ASOS………………….8.4
DAVIS…………………7.8 NNE [31 degrees]

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……….3.91   DEPARTURE………….+0.14
ASOS…………..4.04
TOTAL PRECIPITATION FOR THE YEAR……….41.92   DEPARTURE………….+3.13
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/+3/0.00/731/99         17 WSW AERO 16 MPH WSW RMY 18
9/20 78/54/66/+4/0.00/706/96         18 SSW AERO 18 MPH SSW RMY 23
9/21 74/57/66/+4/T/512/70            35 S   AERO 40 MPH S   RMY N/A
9/22 70/49/60/-1/0.39/365/50         38 S   AERO 39 MPH S   RMY 42
9/23 63/43/53/-7/0.00/711/98         25 NW  AERO 26 MPH NW  RMY 28
9/24 65/40/53/-7/0.00/702/97         22 ENE AERO 22 MPH ENE RMY 23
9/25 64/45/55/-5/0.00/512/71         18 N   AERO 18 MPH N   RMY 19
9/26 63/52/58/-1/0.00/…/..         16 ENE AERO 14 MPH ENE RMY 16
9/27 64/52/58/-1/0.00/…/..         21 NE  AERO 20 MPH NE  RMY 20
9/28 70/52/61/+3/0.00/…/..         16 NNE AERO 15 MPH NNE RMY 15

9/30 our morning low temp: 50F; the normal low is now 49F

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 29
HIGH 85F IN 1952
LOW 28F IN 1914 (SEPTEMBER MINIMUM RECORD)
PRECIP 2.61 INCHES IN 1907
PEAK GUST 62 MPH S IN 2005

RECORDS FOR SEPTEMBER 30
HIGH 84F IN 1986
LOW 31F IN 1992
PRECIP 1.93 INCHES IN 1946
PEAK GUST 58 MPH SSE IN 1999

TODAY’S REPORT PREPARED BY: Forrest Iwanik