Monday, May 1, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, MAY 1, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

MORNING DRIZZLE ENDS BEFORE 1:00PM EST OBSERVATION

Precip. measured 0.04 in. this morning from rain showers
which began yesterday past 1:00PM.  Light drizzle began
before 7:00AM today and continued past the 10:00AM ob
but did not leave a measurable amount of precip.  Fog
began clearing in the early afternoon lifting visibility
to 10-20 miles at 1:00PM. Temperatures rose to 49F from
an overnight low of 43F.  Wind speeds have been light all
day.  Wind direction switched from the east-southeast to
northeast around 8:00AM.

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: N/A

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:N/A
Astronomical total minutes: N/A

Today’s Observations:

7 A.M.
Weather: Light drizzle, fog, overcast nimbostratus
Temperature: 45F; Dew Point: 43F; Wind: estimated SSE at 3 kts,
Wind Speed: Light
Sea-level pressure: 30.06 ins. Hg, falling, then more slowly
Visibility: 2 miles
6-hr Max temp: 45F
6-hr Min temp: 43F
24-hr precip: 0.04 in.
BHO SA 1155 E4 OVC 2L-F 180/45/43/E1503/006/ PCPN VRY LGT WND LGT/
8/6// 56012 MANUAL 70004 ASOS 70004 10045 20043

10 A.M.
Weather: Light drizzle, sky obscurement due to fog
Temperature: 46F; Dew Point: 44F; Wind: NE at 6 kts,
Wind Speed: Light
Sea-level pressure: 30.04 ins. Hg, falling, then more quickly
Visibility: 1/4 mile
3-hr precip: Trace
BHO SA 1455 W2 X 1/4L-F 175/46/44/0406/004/
PCPN VRY LGT WND LGT/ 8//// 58005 MANUAL 600//

1 P.M.
Weather: Overcast stratus
Temperature: 48F; Dew Point: 44F; Wind: NE at 6 kts,
Wind Speed: Light
Sea-level pressure: 29.98 ins. Hg, falling, then more quickly
Visibility: 20 miles, except 10 miles WSW-NE, distant fog WSW-NE
6-hr Max temp: 49F
6-hr Min temp: 44F
6-hr precip: Trace
BHO SA 1755 E6 OVC 20 154/48/44/0406/998/ VSBY WSW-NE 10 DSNT FG WSW-NE
WND LGT/ 8/6// 58021 MANUAL 600// 10049 20044

SUMMARY FOR SUNDAY, APRIL 30, 2017

TEMPERATURE (DEGREES F)
MAX…..60   NORMAL…..61
MIN…..43   NORMAL…..43
MEAN….52   NORMAL…..52

DEPARTURE FROM 30-YEAR NORMAL……………………..0
TOTAL DEPARTURE FOR THE MONTH…………………..+137 [+4.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..13   DEPARTURE………..0
TOTAL HEATING UNITS FOR THE MONTH………….431   DEPARTURE……..-120
TOTAL HEATING UNITS FOR THE SEASON………..5333   DEPARTURE……..-702
TOTAL HEATING UNITS LAST SEASON TO DATE……4992   DIFFERENCE…….+341

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….25  E  AT  1:16 P.M.
AERO……………………25 WNW AT 12:23 A.M.
ASOS……………………27 WNW AT 12:23 A.M.
DAVIS…………………..23 NNW AT  1:32 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY…………………19  E  AT  1:15 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………20  E  AT  1:16 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..17  E  AT  1:16 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..9.9 SE
ASOS…………………..9.7
DAVIS………………….8.3 ENE [070 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.04  DEPARTURE……-0.09
ASOS…………..0.04
TOTAL PRECIPITATION FOR THE MONTH……….6.69  DEPARTURE……+2.14
ASOS…………..6.80
TOTAL PRECIPITATION FOR THE YEAR……….20.81  DEPARTURE……+2.26
ASOS……………N/A ***
*** ASOS annual total 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…………….2.7  DEPARTURE…….-0.3
TOTAL SNOWFALL FOR THE SEASON…………..66.4  DEPARTURE…….+3.7

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/…/..           22 NE  AERO 22 NNE RMY 20
4/23 65/37/51/+1/0.00/0.0/…/..           28 S   AERO 26 S   RMY 28
4/24 69/42/56/+6/0.00/0.0/…/..           23 SSW*AERO 22 SSW*RMY N/A
4/25 49/42/46/-4/…./0.0/…/..           35 NE  AERO 36 NE  RMY 35
4/26 60/47/54/+3/…./0.0/…/..           29 ENE AERO 28 ENE RMY N/A
4/27 66/50/58/+7/0.00/0.0/…/..           20 S   AERO 20 S   RMY N/A
4/28 81/56/69/+17/…/…/…/..           25 W   AERO 23 W   RMY 26
4/29 83/60/72/+20/0.00/0.0/…/..          43 WNW AERO 46 WNW RMY 47
4/30 60/43/52/0/0.04/0.0/…/..            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/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

5/1  Low temp since midnight is 43F; normal low is now 43F

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

RECORDS FOR MAY 1
HIGH 87F IN 1899
LOW 29F IN 1978
PRECIP 2.53 INCHES IN 1921
SNOWFALL TRACE IN 1905,1917,1921,1995,2016
PEAK GUST 57 MPH NW IN 1974

RECORDS FOR MAY 2
HIGH 92F IN 2001
LOW 29F IN 1903
PRECIP 1.36 INCHES IN 2006
SNOWFALL 1.0 INS IN 1888
PEAK GUST 58 MPH S IN 1983

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle