Saturday, May 21, 2016

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 21, 2016
ALL TIMES ARE IN EASTERN STANDARD TIME

HAZY SUNSHINE THIS MORNING DUE TO LINGERING SMOKE ALOFT…
CLOUDS ADVANCED ALL MORNING AND COVERED THE SKY BY LATE
MORNING AS WEAK STORM APPROACHES FROM THE SOUTHWEST…

High clouds were already advancing into a very sunny sky
early this morning. Haze and smoke aloft continued to
filter the sunshine somewhat until cirrostratus, then
lower altostratus and altocumulus moved in. For a
time, cirrocumulus undulatus were observed overhead
around mid-morning. The dew point dropped into the middle
30’s by late morning as drier air mixed down to the
surface from above, and this helped to raise the
visibility from 45 miles to nearly 70 miles by the
1 PM EDT observation.

Today’s Observations:

7 A.M.
Weather: Thin scattered cirrus, hazy, haze and smoke aloft
Temperature: 60F; Dew Point: 43F; Wind: W at 10 kts
Sea-level pressure: 30.17 ins. Hg, rising, then falling
Visibility: 45 miles
6-hr Max temp: 60F
6-hr Min temp: 53F
24-hr precip: 0.00 in.
BHO SA 1155 250 -SCT 45 217/60/43/2610/017/ HAZY HZ/K LYR
ALF/ 8/001 50001 10060 20053

10 A.M.
Weather: Scattered altocumulus, scattered cirrostratus,
thin overcast cirrus fibratus, few small cumulus forming
all quadrants, few altocumulus lenticularis, few cirrocumulus
undulatus overhead, hazy
Temperature: 73F; Dew Point: 36F; Wind: S at 8 kts,
Sea-level pressure: 30.13 ins. Hg, falling
Visibility: 45 miles
BHO SA 1455 180 SCT 200 SCT 250 -OVC 45 203/73/36/1808/013/
FEW SML CU FRMG ALQDS FEW ACSL OVHD FEW CC OVHD HAZY/ 8/137
56014

1 P.M.
Weather: Scattered altocumulus, overcast altostratus, few
cumulus distant WNW-N, higher clouds visible distant W-NNE,
sun dimly visible
Temperature: 69F; Dew Point: 37F; Wind: S at 11G17 kts
Sea-level pressure: 30.08 ins. Hg, falling, then more quickly
Visibility: 65 miles
6-hr Max temp: 73F
6-hr Min temp: 60F
BHO SA 1755 140 SCT 170 OVC 65 187/69/37/1811G17/008/ FEW CU
DSNT WNW-N HIR CLDS VSBL DSNT W-NNE SUN DMLY VSBL VSBY NW 75
LGT DSNT HZ/ 8/177 58016 10073 20060

SUMMARY FOR FRIDAY, MAY 20, 2016

TEMPERATURE (DEGREES F)
MAX…..73   NORMAL…..68
MIN…..46   NORMAL…..49
MEAN….60   NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL……………………..+2
TOTAL DEPARTURE FOR THE MONTH…………………….-39 [-2.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………5   DEPARTURE……….-3
TOTAL HEATING UNITS FOR THE MONTH………….229   DEPARTURE………+29
TOTAL HEATING UNITS FOR THE SEASON………..5221   DEPARTURE…….-1014
TOTAL HEATING UNITS LAST SEASON TO DATE……6374   DIFFERENCE……-1153

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….20 SSE AT 18:08 P.M.
ASOS……………………20 SSE AT 18:02 P.M.
DAVIS…………………..19 SE  AT 18:05 P.M. RMY 21
FASTEST MILE FOR YESTERDAY…………………14 SSE AT 18:10 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE………………14 SW  AT 11:47 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..14 SE  AT 18:09 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..9.5 WNW
ASOS…………………..8.7
DAVIS………………….8.0 W [260 Deg.] * Last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.13
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….2.14  DEPARTURE……-0.34
ASOS…………..2.02
TOTAL PRECIPITATION FOR THE YEAR……….19.08  DEPARTURE……-1.95
ASOS………….19.02

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE MONTH…………..TRACE  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE SEASON…………..57.5  DEPARTURE…….-5.7

PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO/RMY GUST
AERO: Aerovane wind recording system 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

5/1 52/39/46/-7/0.08/T/000/00               21 S   AERO 22 SE  RMY 20
5/2 50/41/46/-7/0.31/0.0/000/00             20 NE  AERO 21 NE  RMY 18
5/3 48/43/46/-7/0.16/0.0/000/00             16 E   AERO 16 E   RMY 17
5/4 48/41/45/-9/0.53/0.0/000/00             33 NE  AERO 35 NE  RMY 34
5/5 44/41/43/-11/0.30/0.0/000/00            39 NNE AERO 41 NNE RMY 39
5/6 54/43/49/-5/0.13/0.0/360/42             28 ENE AERO 29 N   RMY 26
5/7 51/43/47/-8/…/0.0/000/00              25 NE  AERO 25 NE  RMY 23
5/8 60/46/53/-2/…/0.0/284/33              47 W   AERO 53 W   RMY 49
5/9 65/43/54/-1/0.00/0.0/743/86             40 W   AERO 44 W   RMY 40
5/10 69/40/55/0/0.00/0.0/806/93             22 W   AERO 25 WNW RMY 22
5/11 76/50/63/+7/0.00/0.0/808/93            22 WNW AERO 23 WNW*RMY 22
5/12 75/54/65/+9/0.00/0.0/819/94            23 NNE AERO 25 S   RMY 23
5/13 74/52/63/+7/0.21/0.0/079/09            27 S   AERO 27 S   RMY 26
5/14 78/54/66/+9/0.00/0.0/…/..            35 SSW*AERO 40 SSW RMY 37
5/15 60/41/51/-6/0.00/0.0/…/..            50 W   AERO 54 W   RMY 49
5/16 58/38/48/-9/0.00/0.0/…/..            45 W*  AERO 51 WNW RMY 49
5/17 69/47/58/+1/0.00/0.0/…/..            32 W   AERO 38 W   RMY 38
5/18 64/48/56/-2/0.00/0.0/…/..            24 NE  AERO 26 NNW RMY N/A
5/19 66/49/58/0/0.26/0.0/…/..             23 WNW AERO 26 WNW RMY 25
5/20 73/46/60/+2/0.00/0.0/…/..            20 SSE AERO 22 SSE RMY 21

5/21 low temp since midnight is 53F; normal low now 49F

* Last of several occurrences
* All sunshine data corrected to astronomical minutes.

DAILY RECORDS FOR MAY 2016

5/1/16: DAILY RECORD SNOWFALL OF A TRACE,
TIES PREVIOUS RECORDS SET IN 1905, 1917, 1921, and 1995

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

RECORDS FOR MAY 21
HIGH 92F IN 1921
LOW 35F IN 1907
PRECIP 1.61 INS IN 1954
PEAK GUST 74 MPH WSW IN 2006

RECORDS FOR MAY 22
HIGH 93F IN 1911
LOW 35F IN 1907
PRECIP 3.75 INCHES IN 1920
PEAK GUST 49e MPH SSW IN 1947

TODAY’S REPORT PREPARED BY: Mike Iacono