Tuesday, October 1, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, OCTOBER 1, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

TEMPERATURES MODERATING UNDER MOSTLY CLEAR SKY;
DRY SPELL CONTINUES;
SEPTEMBER FINISHES ON THE COOL AND SLIGHTLY DRY SIDE

The sky has been mostly sunny today, with the only clouds of note well
off to our east. Winds have finally departed from the recent, persistent
N-NE flow. The direction today has primarily been from the WNW. The change
in wind direction, relatively calm conditions, and plentiful sunshine have
helped push the afternoon high into the mid 70s. Consequently, today’s
average temperature will likely finish a few degrees above the 30-year
normal for the date.

The streak of dry weather continues. The last measurable rainfall
occurred nearly 10 days ago on September 22. From September 3 through
October 1, rainfall has only amounted to 1.16 inches, which is only 29%
of the 30-year normal for this period.

A list of current record high temperatures is shown below in anticipation
of possible near record warmth this week.

OCTOBER 1 85F IN 1927
OCTOBER 2 85F IN 1968
OCTOBER 3 82F IN 1922
OCTOBER 4 84F IN 2007

SEPTEMBER 2013 PRELIMINARY STATISTICS:
(departures relative to 1981-2010 average)

TEMPERATURE:
Average Max Temp: 71.7F [+0.1F] Average Min Temp: 52.5F [-2.1F] Mean Temp: 62.1F [-1.0F] 24-hr. Corr. Mean Temp: 61.9F [-0.2F] Max Temp: 93F on 11th
Min Temp: 40F on 17th and 24th

Total heating degree day units (month): 134 [+17] *NCDC method
Total heating degree day units (season): 146 [+4] *start July 1 (NCDC)
Total cooling degree day units (month): 56 [-4] *NCDC method
Total cooling degree day units (season): 696 [+99] *start Jan 1 (NCDC)

PRECIPITATION:
Total precipitation: 3.91 inches [-0.15 inch] Greatest 24-hr precipitation: 2.44 inches on 1st/2nd

WIND:
Avg wind speed: 10.0 MPH
Avg corrected wind speed: 10.6 MPH
Prevailing wind direction: W [12%] Peak gust: 38 MPH S on 22nd
Peak fastest mile: 30 MPH S on 21st

SUNSHINE:
Updates in the next couple of days.

Today’s Observations:

7 A.M.
Weather: Scattered altocumulus, scattered thin cirrus, few altocumulus
castellanus distant E, altocumulus/altocumulus lenticularis NE-SSE, cirrus
NE-E-S, inversion present, few patches of ground fog E-S-NW below inversion,
thin smoke layer along horizon below inversion all quadrants, dew all
surfaces, light distant haze
Temperature: 52F; Dew Point: 48F; Wind: NW at 11 kts.
Sea-level pressure: 29.96 ins. Hg, rising
Visibility: 70 miles, NW 75 miles, N-SE lower, light distant haze
6-hour min. temp: 50F
BHO SA 1155 120 SCT 250 –SCT 70 147/52/48/3211/996/ FEW ACC DSNT E AC/ACSL
NE-SSE CI NE-E-S INVSN PRSNT FEW PTCHS GF E-S-NW BLO INVSN THN K LYR ALG
HRZN BLO INVSN ALQDS DEW ALL SFCS LGT DSNT HZ VSBY NW 75 N-SE LWR/ 8/081
53006 10052 20050

10 A.M.
Weather: Scattered cirrostratus, scattered thin cirrus, lone cumulus
fractus WNW, few altocumulus/altocumulus lenticularis distant NE-SE,
cirrostratus/cirrus distant NE-S, thin smoke layer above horizon all
quadrants, light distant haze
Temperature: 65F; Dew Point: 53F; Wind: WNW at 4 kts.
Sea-level pressure: 29.96 ins. Hg, rising then falling
Visibility: 70 miles, light distant haze
BHO SA 1455 200 SCT 250 –SCT 70 144/65/53/3104/996/ LONE CUFRA WNW FEW
AC/ACSL DSNT NE-SE CS/CI DSNT NE-S THN K LYR ABV HRZN ALQDS LGT DSNT HZ/
8/147 58003

1 P.M.
Weather: Scattered thin cirrus, few small cumulus distant WSW-WNW,
few altocumulus distant N-NNE, few altocumulus/altocumulus lenticularis
distant ENE-SE, cirrus and a few patches of dense cirrus distant ENE-SE,
thin smoke layer distant W-N-E, light distant haze
Temperature: 74F; Dew Point: 51F; Wind: W at 7 kts,
Wind: Direction variable WSW-NW
Sea-level pressure: 29.89 ins. Hg, decreasing then decreasing more rapidly
Visibility: 65 miles, light distant haze
6-hour max. temp: 75F
BHO SA 1755 250 –SCT 65 125/74/51/2807/989/ FEW SML CU DSNT WSW-WNW FEW
AC DSNT N-NNE FEW AC/ACSL DSNT ENE-SE CI AND FEW PTCHS DNS CI DSNT ENE-SE
THN K LYR DSNT W-N-E LGT DSNT HZ WND 25V32/ 8/237 58019 10075 20052

WEATHER SUMMARY FOR MONDAY, SEPTEMBER 30, 2013

TEMPERATURE (DEGREES F)
MAX…..64 NORMAL…..66
MIN…..51 NORMAL…..49
MEAN….58 NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL………………….0
TOTAL DEPARTURE FOR THE MONTH………………..-25 [-1.0 DEGREE/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………..0 DEPARTURE………-1
TOTAL COOLING UNITS FOR THE MONTH………….56 DEPARTURE………-4
TOTAL COOLING UNITS FOR THE SEASON………..696 DEPARTURE……..+99
TOTAL COOLING UNITS LAST SEASON TO DATE……765 DIFFERENCE…….-69

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..7 DEPARTURE………-1
TOTAL HEATING UNITS FOR THE MONTH…………134 DEPARTURE……..+17
TOTAL HEATING UNITS FOR THE SEASON………..146 DEPARTURE………+4
TOTAL HEATING UNITS LAST SEASON TO DATE…….99 DIFFERENCE…….+47

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………15 NE AT 1:58 P.M. *
AERO…………………..14 ENE AT 2:19 P.M. *
ASOS…………………..15 NE AT 1:57 P.M.
DAVIS………………….14 NE AT 1:15 P.M. RMY N/A
FASTEST MILE FOR YESTERDAY…………………9 W AT 9:17 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE……………..10 W AT 9:19 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….10 NNE AT 1:58 P.M.
AVERAGE WIND SPEED AND DIRECTION………….4.8 NE
ASOS………………….4.4
DAVIS…………………4.4 NNE [032 degrees] * last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00 DEPARTURE………….-0.15
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….3.91 DEPARTURE………….-0.15
ASOS…………..4.04
TOTAL PRECIPITATION FOR THE YEAR……….41.92 DEPARTURE………….+2.84
ASOS…………..N/A*
*ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER & OCTOBER 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/536/70 23 SW AERO 23 MPH SSW RMY N/A
9/10 73/56/65/0/0.03/008/01 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/-1/0.00/503/70 16 ENE AERO 14 MPH ENE RMY 16
9/27 64/53/59/0/0.00/307/43 21 NE AERO 20 MPH NE RMY 20
9/28 70/52/61/+3/0.00/698/98 16 NNE AERO 15 MPH NNE RMY 15
9/29 65/50/58/0/0.00/553/78 15 ESE AERO 15 MPH ESE RMY 15
9/30 64/51/58/0/0.00/…/.. 15 NE AERO 14 MPH ENE RMY N/A

10/1 the 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 RECORDS FOR OCTOBER 2013
None so far.

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

RECORDS FOR OCTOBER 1
HIGH 85F IN 1927
LOW 30F IN 1992
PRECIP 1.44 INCHES IN 1984
PEAK GUST 68e MPH SSE IN 1977

RECORDS FOR OCTOBER 2
HIGH 85F IN 1968
LOW 29F IN 1899
PRECIP 1.75 INCHES IN 1984
PEAK GUST 52e MPH S IN 1952, 52 NNW IN 1984

TODAY’S REPORT PREPARED BY: Sean Fankhauser and Kevin Pecora