Saturday, May 9, 2015
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 9, 2015
ALL TIMES ARE IN EASTERN STANDARD TIME
MAXIMUM OF 74F REACHED BY EARLY YESTERDAY MORNING,
WINDS SHIFT, BACK DOOR FRONT ROLLS THROUGH
CHILLY NORTH ATLANTIC MARINE AIR MASS SETTLES IN
TEMPERATURES DROP TO MID 40’S BY LATE LAST EVENING
TEMPERATURES RISING INTO 70;S AT 8 DEG/HR EARLY AFTERNOON
DEW POINT RISING AT 5 DEG/HR
Low temperatures fell back to 44F by late last
evening and continuing into this morning as low
stratus clouds arrived and settled over the summit.
Visibility dropped to 1/16 mile but was increasing
to 2.5 miles by 7 A.M. EST, the time of our first
observation. It does not appear that any drizzle
accompanied the fog at the summit but there was
some drizzle to the east.
The front which passed over us yesterday moving from the northeast
has returned as a warm front from the southwest today.
Temperatures were rising quickly into the 70;s by early
this afternoon. The much warmer air has returned with
increasing as dew points rise through the 50’s.
PRELIMINARY STATS FOR APRIL 2015
TEMPERATURE, Deg. F
Avg. Max. 55.9 [+0.2]
Avg. Min. 38.4 [+0.7]
Mean 47.2 [+0.5]
Corrected mean: 46.7
Max. for month: 69 on 4/13
Min. for month: 26 on 4/1
HEATING DEGREE DAYS
Total heating units: 528 [-23]
Total for the season: 6271 [+236]
Total for last season: 6171
PRECIPITATION, Inches
Total: 3.33 [-1.22]
Greatest in 24 hrs: N/A
SNOWFALL, Inches
Total: Trace [-3.0]
Greatest in 24 hrs: Trace on 4/8
WIND, mph
Avg. uncorrected wind speed: 12.6
Avg. corrected wind speed: 13.0
Prevailing wind direction: NW @ 16%
Peak gust and direction: 54 NW on the 4th
SUNSHINE:
Astronomical total minutes: 12386 / 24083 or 51%
Campbell-Stokes card minutes: 11946 / 23250 or 51%
Today’s Observations:
7 A.M.
Weather: Low overcast stratus, estimated ceiling 4 hundred feet
Temperature: 47F; Dew Point: 45F; Wind: Estimated at 2 kts WSW
Sea-level pressure: 30.37 ins. Hg, rising, then more slowly
Visibility: 2 1/2 miles slowly increasing in thin fog
6-hr Max temp: 47F
6-hr Min temp: 44F
24-hr precip: none
BHO SA 1155 E4 OVC 21/2F 284/47/45/E2502/037/ VSBY SLWLY INCRSNG
WND L/V/ 8/6// 51007 10047 20044
10 A.M.
Weather: Scattered dense cirrus (overhead-NW-N) thin broken
cirrus, thin overcast cirrus, break in overcast S-SW,
stratocumulus and stratocumulus lenticularis, break in thin
overcast S-SW
Temperature: 61F; Dew Point: 51F; Wind: SSW at 7 kts,
Sea-level pressure: 30.36 ins. Hg, falling slightly
Visibility: 25 miles, except N-NE 12 miles, thin fog,
SSW 30 miles, hazy all quadrants
BHO SA 1455 220 SCT 250 -BKN 300 -OVC 25 281/61/51/2107/036/
BINOVC S-SW SC SSE-SW-DSNT NW THN STRA/FG N-NE DNS CI OVHD-NW-N
VSBY N-NE 12 SSW 30 HAZY ALQDS WND 17V23/ 8/502 58003
1 P.M.
Weather: Scattered dense cirrus, thin broken cirrus at
2 levels, cumulus fractus forming all directions
Temperature: 77F; Dew Point: 57F; Wind: SSW at 15 kts,
Sea-level pressure: 30.30 ins. Hg, falling, then more quickly
Visibility: 30 miles, except 15 miles N, 20 miles NE, hazy,
hazy all quadrants
6-Hr Max temp: 77F
6-Hr Min temp: 47F
6-Hr Precip: none
BHO SA 1755 220 SCT 250 –BKN 300 –BKN 30 262/77/57/2015/030/
CUFRA/CU FRMG ALQDS PTCHS DNS CI VSBY N 15 NE 20 HAZY HAZY
ALQDS/ 8/102 58019 10077 20047
SUMMARY FOR FRIDAY, MAY 8, 2015
TEMPERATURE (DEGREES F)
MAX…..74 NORMAL…..64
MIN…..44 NORMAL…..45
MEAN….59 NORMAL…..55
DEPARTURE FROM 30-YEAR NORMAL…………………..+4
TOTAL DEPARTURE FOR THE MONTH………………….+45 [+5.4 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………6 DEPARTURE…………5
TOTAL HEATING UNITS FOR THE MONTH…………..49 DEPARTURE……….-44
TOTAL HEATING UNITS FOR THE SEASON………..6320 DEPARTURE………+193
TOTAL HEATING UNITS LAST SEASON TO DATE……6244 DIFFERENCE………+76
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………27 NNE AT 2:02 P.M.
ASOS…………………..27 ENE AT 2:08 P.M.
DAVIS………………….25 NE AT 10:35 A.M. RMY 26
FASTEST MILE FOR YESTERDAY………………..20 NE AT 2:25 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………..21 NE AT 10:09 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….18 NE AT 10:09 A.M.
AVERAGE WIND SPEED AND DIRECTION…………12.3 NE
ASOS…………………12.1
DAVIS………………..11.4 NE [050 degrees]
* Last of several occurrences…
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…..0.00 DEPARTURE…..-0.12
ASOS……………0.00
TOTAL PRECIPITATION FOR THE MONTH………..0.03 DEPARTURE…..-0.96
ASOS……………0.03
TOTAL PRECIPITATION FOR THE YEAR………..17.95 DEPARTURE…..-1.46
ASOS…………….N/A ***
*** ASOS annual totals not available due to erroneous readings
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M………..0.0 DEPARTURE……0.0
TOTAL SNOWFALL FOR THE MONTH……………..0.0 DEPARTURE……0.0
TOTAL SNOWFALL FOR THE SEASON…………..150.8 DEPARTURE….+88.1
PRELIMINARY CLIMATE SUMMARY FOR APRIL CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY 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
4/1 44/26/35/-6/0.00/0.0/748/98 30 WNW RMY 31
4/2 59/29/44/+3/T/0.0/375/49 39 SSW RMY 43
4/3 56/47/52/+10/0.02/0.0/000/00 36 SW RMY N/A
4/4 49/32/41/-1/0.32/0.0/501/65 54 NW RMY 64 TSTM
4/5 47/30/39/-4/T/0.0/464/60 40 W RMY 45
4/6 48/33/41/-2/0/00/0.0/544/70 18 NE RMY N/A
4/7 39/34/37/-6/0.13/0.0/000/00 21 NE RMY N/A
4/8 41/32/37/-7/0.51/T/000/00 30 ENE RMY 32
4/9 35/32/34/-10/0.38/0.0/000/00 31 ENE RMY 32
4/10 53/35/44/-1/0.07/0.0/000/00 31 SW RMY N/A
4/11 56/38/46/+1/0.00/0.0/744/94 39 WNW RMY 48
4/12 68/35/52/+7/0.00/0.0/762/96 23 WNW RMY 23
4/13 69/47/58/+12/0.00/0.0/764/96 35 SSW RMY N/A
4/14 65/51/58/+12/0.05/0.0/072/09 37 SSW RMY N/A
4/15 67/45/56/+9/0.00/0.0/786/98 32 NW RMY 33
4/16 64/42/53/+6/0.00/0.0/765/95 31 S RMY 21
4/17 64/45/55/+8/0.05/0.0/065/08 31 SSW RMY 32
4/18 64/43/54/+6/0.00/0.0/770/95 31 N RMY 36
4/19 55/39/47/-1/0.00/0.0/724/89 25 NNW RMY N/A
4/20 55/38/47/-2/1.00/0.0/000/00 36 SE RMY 40
4/21 67/51/59/+10/0.44/0.0/417/51 30 SSE RMY N/A TSTM
4/22 67/45/56/+7/0.03/0.0/632/77 44 SSW RMY 52
4/23 49/34/42/-8/0.00/0/0/362/44 32 W RMY N/A
4/24 50/32/41/-9/0.00/0.0/562/68 32 NW RMY 36
4/25 56/30/43/-7/0.00/0.0/638/77 26 NW RMY 29
4/26 54/39/47/-4/0.00/0.0/258/31 17 NW RMY N/A
4/27 56/42/49/-2/0.15/0.0/125/15 30 NW RMY N/A
4/28 63/39/51/-1/0.10/0.0/527/63 32 NW RMY 35
4/29 58/46/52/+0/T/0.0/461/55 24 ENE RMY 22
4/30 60/42/51/-1/0.00/0.0/320/38 21 NE RMY N/A
PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY 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 52/37/45/-8/0.00/0.0/…/.. 21 NE RMY 20
5/2 63/35/49/-4/0.00/0.0/…/.. 20 S RMY 20
5/3 74/44/59/+6/0.00/0.0/…/.. 22 S RMY 22
5/4 83/47/65/+11/0.00/0.0/…/.. 39 SSW RMY 45
5/5 77/56/67/+13/0.03/0.0/…/.. 29 SW RMY N/A
5/6 74/54/64/+10/0.00/0.0/…/.. 24 SSW RMY 25
5/7 84/52/68/+13/0.00/0.0/…/.. 29 S RMY 32
5/8 74/44/59/+4/0.00/0.0/…/.. 27 NNE RMY 26
5/9 low since midnight is 44F; normal low now 46F
DAILY RECORDS FOR MAY 2015
NONE SO FAR
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
RECORDS FOR MAY 9
HIGH 93F IN 2000
LOW 31F IN 1947
PRECIP 2.72 INCHES IN 1954
SNOWFALL 5.0 INS IN 1977 (RECORD FOR MAY)
PEAK GUST 70e MPH NE IN 1977
RECORDS FOR MAY 10
HIGH 93F IN 1896
LOW 29F IN 1900
PRE 1.85 INS IN 1998
SNOW 2.8 INS 1977 (7.8 INS TOTAL 5/9-5/10 1977)
PEAK GUST 64 MPH S IN 1990
TODAY’S REPORT PREPARED BY: Robert Skilling
