Thursday, May 4, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, MAY 4, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

ANOTHER DAY OF SUNSHINE AND 70 MILE VISIBILITY

Normal and mild conditions continued today with rising
pressure. Skies were mostly cloudy with high cirrus
clouds which still allowed abundant sunshine.  Mid-level
clouds were moving in by afternoon.  Overnight temperatures
reached a chilly 40F, but had risen to 63F by 1:00PM EST.
Dew points remained in the upper 20s making for a dry and
very pleasant day.  Visibility remained at 70 miles.

PRELIMINARY STATS FOR APRIL 2017

TEMPERATURE, Deg. F
Avg. Max. 60.6 [+4.9] Avg. Min. 41.3 [+3.6] Mean      51.0 [+4.3] 24-hour corrected mean: 50.1
Max. for month: 86F on 16th
Min. for month: 30F on 2nd

HEATING DEGREE DAYS
Total heating units: 431 [-120] Total for the season: 5333 [-702] Total for last season: 4992

COOLING DEGREE DAYS
Total cooling units: 20 [+18] Total for the season: 20 [+18] Total for last season: 3

PRECIPITATION, Inches
Total: 6.69 [+2.14] Greatest in 24 hrs: 2.21 in. on 1st

SNOWFALL, Inches
Total: 2.7 [-0.3] Greatest in 24 hrs: 2.7 in. on 1st

WIND, mph
Avg. uncorrected wind speed: 12.4
Avg. corrected wind speed: 12.8
Prevailing wind direction: S at 10%
Peak gust and direction: 43 SSW on 7th and 43 WNW on 29TH

SUNSHINE:
Campbell-Stokes card minutes: 11,358 minutes of possible 23,250 or 49%
Astronomical total minutes: 11,797 minutes of possible 24,126 or 49%

BHO Warmest April 24-Hour Mean Temperature, deg F (1885-2017):

1) 51.5 in 2010
2) 51.0 in 1976
3) 50.1 in 2017
4) 49.9 in 2012
5) 49.4 in 1945
6) 49.0 in 1994
7) 48.9 in 2005
48.9 in 2009

Today’s Observations:

7 A.M.
Weather: Broken cirrus, patches of cirrocumulus WNW
Temperature: 48F; Dew Point: 32F; Wind: NNW at 4 kts,
Wind Speed: Light
Sea-level pressure: 30.28 ins. Hg, rising, then more slowly
Visibility: 70 miles
6-hr Max temp: 48F
6-hr Min temp: 40F
24-hr precip: 0.00 in.
BHO SA 1155 E250 BKN 70 254/48/32/3404/028/ PTCHS CC WNW WND LGT/
8/009 51028 10048 20040

10 A.M.
Weather: Broken cirrus
Temperature: 56F; Dew Point: 25F; Wind: SE at 5 kts,
Wind Speed: Light
Sea-level pressure: 30.31 ins. Hg, steady then rising
Visibility: 70 miles
BHO SA 1455 E250 BKN 70 264/56/25/1305/031/ WND LGT/ 8/001 53010

1 P.M.
Weather: scattered altocumulus, broken cirrus
Temperature: 62F; Dew Point: 23F; Wind: ESE at 5 kts,
Wind Speed: Light
Sea-level pressure: 30.25 ins. Hg, falling, then more quickly
Visibility: 70 miles
6-hr Max temp: 63F
6-hr Min temp: 48F
BHO SA 1755 SCT 120 E250 BKN 70 245/62/23/1105/025/ WND LGT/
8/082 56019 10063 20048

SUMMARY FOR WEDNESDAY, MAY 3, 2017

TEMPERATURE (DEGREES F)
MAX…..63   NORMAL…..63
MIN…..42   NORMAL…..44
MEAN….53   NORMAL…..53

DEPARTURE FROM 30-YEAR NORMAL……………………..0
TOTAL DEPARTURE FOR THE MONTH…………………….-5 [-1.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..12   DEPARTURE………..0
TOTAL HEATING UNITS FOR THE MONTH…………..41   DEPARTURE……….+4
TOTAL HEATING UNITS FOR THE SEASON………..5374   DEPARTURE……..-698
TOTAL HEATING UNITS LAST SEASON TO DATE……5049   DIFFERENCE…….+325

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….37 WNW AT 4:45 P.M.*
AERO……………………39 WNW AT 4:45 P.M.
ASOS……………………39 NW  AT 4:45 P.M.
DAVIS…………………..37 NNW AT 4:46 P.M. RMY 40
FASTEST MILE FOR YESTERDAY…………………28 WNW AT 4:45 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………28 NW  AT 4:46 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..27 NW  AT 4:46 P.M.
AVERAGE WIND SPEED AND DIRECTION………….15.1 W
ASOS………………….14.5
DAVIS…………………13.4 WNW [300 deg.] *LAST OF MULTIPLE 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……….0.26  DEPARTURE……+0.11
ASOS…………..0.27
TOTAL PRECIPITATION FOR THE YEAR……….21.07  DEPARTURE……+2.17
ASOS……………N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR APRIL CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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
M:    Missing data

4/1  35/31/33/-8/2.21/2.7/000/00           40 ENE AERO 41 ENE RMY 41
4/2  53/30/42/+1/0.00/0.0/552/72           32 NW  AERO 33 NW  RMY 34
4/3  60/35/48/+6/0.00/0.0/685/89           21 W*  AERO 20 NW  RMY N/A
4/4  42/35/39/-3/0.78/0.0/000/00           41 ESE AERO 43 ESE RMY 42
4/5  41/35/38/-5/0.00/0.0/000/00           21 NNW AERO 20 NNW RMY N/A
4/6  55/35/45/+2/1.27/0.0/000/00           35 SSE AERO 37 S   RMY 37  TSTM
4/7  53/38/46/+3/0.00/0.0/226/29           43 SSW AERO 47 SSW RMY 48
4/8  50/34/42/-2/0.00/0.0/666/85           37 WNW AERO 40 WNW RMY 39
4/9  65/34/50/+6/0.00/0.0/716/91           23 W   AERO 23 W   RMY N/A
4/10 77/45/61/+16/0.00/0.0/560/71          37 S   AERO 37 S   RMY 39
4/11 85/50/68/+23/0.00/0.0/642/81          28 S   AERO 28 S   RMY 30
4/12 68/47/58/+13/0.01/0.0/382/48          26 WNW AERO 28 WNW RMY N/A
4/13 58/39/49/+3/0.00/0.0/567/71           28 WNW AERO 31 NW  RMY 30
4/14 62/40/51/+5/0.00/0.0/801/100          22 NNW AERO 22 NNW RMY 24
4/15 68/40/54/+7/0.01/0.0/675/84           40 SSW AERO 45 SSW RMY 45
4/16 86/55/71/+24/T/0.0/758/94             38 W*  AERO 39 SW  RMY 42
4/17 75/48/62/+15/0.00/0.0/405/50          37 W   AERO 37 W   RMY 43
4/18 52/35/44/-4/0.00/0.0/779/96           25 ENE AERO 23 ENE RMY 25
4/19 54/34/44/-4/0.06/0.0/431/53           31 S   AERO 33 S   RMY 34
4/20 58/41/50/+1/0.05/0.0/270/33           25 SSW AERO 24 SSW RMY 23
4/21 45/42/44/-5/0.50/0.0/000/00           26 ESE AERO 29 ESE RMY 28
4/22 44/40/42/-7/0.14/0.0/000/00           22 NE  AERO 22 NNE RMY 20
4/23 65/37/51/+1/0.00/0.0/809/98           28 S   AERO 26 S   RMY 28
4/24 69/42/56/+6/0.00/0.0/562/68           23 SSW*AERO 22 SSW*RMY N/A
4/25 49/42/46/-4/0.97/0.0/000/00           35 NE  AERO 36 NE  RMY 35
4/26 60/47/54/+3/0.63/0.0/000/00           29 ENE AERO 28 ENE RMY N/A
4/27 66/50/58/+7/T/0.0/134/16              20 S   AERO 20 S   RMY N/A
4/28 81/56/69/+17/0.02/0.0/453/54          25 W   AERO 23 W   RMY 26
4/29 83/60/72/+20/0.00/0.0/294/35          43 WNW AERO 46 WNW RMY 47
4/30 60/43/52/0/0.04/T/430/51              25 E   AERO 25 WNW RMY N/A

DAILY RECORDS FOR APRIL 2017

4/11/17: DAILY RECORD MAXIMUM TEMPERATURE OF 85F,
BREAKS PREVIOUS RECORD OF 78F SET IN 1945

4/11/17: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 50F,
TIES WITH PREVIOUS RECORD SET IN 1955

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
M:    Missing data

5/1  50/43/47/-6/T/…/..                  21 N   AERO 18 N   RMY 22
5/2  65/42/54/+1/0.26/…/..               41 W   AERO 44 W   RMY 43
5/3  52/42/53/0/0.00/…/..                37 WNW*AERO 39 WNW RMY 40

5/4  Low temp since midnight is 40F; normal low is now 44F

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

RECORDS FOR MAY 4
HIGH 90F IN 2001
LOW 27F IN 1911 (RECORD FOR MAY)
PRECIP 1.92 INCHES IN 1893
SNOWFALL 0.1 INCHES IN 1920
PEAK GUST 60 MPH NW IN 1966

RECORDS FOR MAY 5
HIGH 92F IN 1949
LOW 30F IN 1891
PRECIP 2.74 INCHES IN 1922
SNOWFALL 3.0 INCHES IN 1917
PEAK GUST 58 MPH S IN 1966 & 58e MPH SW IN 1976

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle