Tuesday, May 2, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, MAY 2, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

MORNING THUNDERSTORM BRINGS 0.26 IN. OF RAIN,
FOG AND OVERCAST SKIES PERSIST INTO EARLY AFTERNOON

The 0.26 in. of precip. which fell during a thunderstorm
this morning is 0.14 in. above normal, giving May a head
start on its monthly precip. departure.  Light drizzle
continued on and off through the morning leaving just a
trace by 1:00PM EST.

The top of Great Blue Hill was obscured in fog this morning,
and skies remained overcast into early afternoon.  Visibility
only cleared to 5-10 miles at the 1:00PM observation.  Winds
shifted from south to north-northwest near 12:30PM and became
light with the passage of the cold front.

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:N/A
Astronomical total minutes: N/A

Today’s Observations:

7 A.M.
Weather: Sky obscurement due to fog
Temperature: 52F; Dew Point: 52F; Wind: S at 14 kts
Sea-level pressure: 29.63 ins. Hg, falling then rising
Visibility: 1/8 mile
6-hr Max temp: 52F
6-hr Min temp: 42F
24-hr precip: 0.26 in.
BHO SA 1155 W2 X 1/8F 034/52/52/1814/963/ 8//// 55019 MANUAL 70026
ASOS 70027 10052 20042

10 A.M.
Weather: Light drizzle, sky obscurement due to fog
Temperature: 61F; Dew Point: 61F; Wind: S at 13G18 kts
Sea-level pressure: 29.56 ins. Hg, falling, then more slowly
Visibility: 2 miles
3-hr precip: Trace
BHO SA 1455 W3 X 2L-F 011/61/61/1913G18/956/ PCPN VRY LGT/
8//// 56023 MANUAL 600//

1 P.M.
Weather: Fog, overcast stratus
Temperature: 56F; Dew Point: 55F; Wind: NNW at 5 kts,
Wind Speed: Light
Sea-level pressure: 29.83 ins. Hg, falling, then more slowly
Visibility: 5 miles, except 10 miles ESE-S, distant fog ESE-S
6-hr Max temp: 62F
6-hr Min temp: 52F
6-hr precip: Trace
BHO SA 1755 E4 OVC 5F 001/56/55/3305/983/ VSBY ESE-S 10 DSNT FG ESE-S
WND LGT/ 8/6// 56010 MANUAL 600// 10062 20052

SUMMARY FOR MONDAY, MAY 1, 2017

TEMPERATURE (DEGREES F)
MAX…..50   NORMAL…..62
MIN…..43   NORMAL…..43
MEAN….47   NORMAL…..53

DEPARTURE FROM 30-YEAR NORMAL…………………….-6
TOTAL DEPARTURE FOR THE MONTH…………………….-6 [-6.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..18   DEPARTURE……….+5
TOTAL HEATING UNITS FOR THE MONTH…………..18   DEPARTURE……….+5
TOTAL HEATING UNITS FOR THE SEASON………..5351   DEPARTURE……..-696
TOTAL HEATING UNITS LAST SEASON TO DATE……5011   DIFFERENCE…….+340

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….21  N  AT 11:58 P.M.
AERO……………………18  N  AT 11:58 P.M.
ASOS……………………21 NNW AT 11:56 P.M.
DAVIS…………………..20  N  AT 11:59 P.M. RMY N/A
FASTEST MILE FOR YESTERDAY…………………16  E  AT  8:15 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………16  E  AT  9:51 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..14  N  AT 11:57 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..7.4 NE
ASOS…………………..8.1
DAVIS………………….6.0 E [100 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.26  DEPARTURE……+0.14
ASOS…………..0.27
TOTAL PRECIPITATION FOR THE MONTH……….0.26  DEPARTURE……+0.14
ASOS…………..0.27
TOTAL PRECIPITATION FOR THE YEAR……….21.07  DEPARTURE……+2.40
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/+1/0.00/0.0/780/98           28 S   AERO 26 S   RMY 28
4/24 69/42/56/+6/0.00/0.0/540/68           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/0.0/132/16              20 S   AERO 20 S   RMY N/A
4/28 81/56/69/+17/0.02/…/…/..          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/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/…./…/..               21 N   AERO 18 N   RMY 22

5/2  Low temp since midnight is 42F; 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 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

RECORDS FOR MAY 3
HIGH 92F IN 2001
LOW 31F IN 1888
PRECIP 2.25 INS IN 1900
SNOWFALL TRACE IN 1908, 1985
PEAK GUST 71 MPH W IN 2002

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle