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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, APRIL 23, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME

HIGH PRESSURE SYSTEM BRINGS DRY AIR, SUNNY SKIES, 
ABOVE SEASONABLE TEMPERATURES TO GREAT BLUE HILL...

We observed very high pressure which brought dry, 
warm air to the area. Temperatures began seasonable 
with an overnight low of 40F, which is 1 degrees 
above the daily normal of 40F. Temperature quickly 
rose after sunrise and we reached a max so far of 
62F by 1:00 P.M. Already three degrees above the 
daily normal of 59F. We observed low dew points 
and humidity all day which made for excellent
visibility at each observation. We had an very a 
low humidity of 15% at 1:00 P.M. Skies remained 
clear with only a few cirrostratus clouds. We 
had light wind and variable wind today eventually 
settling from the east in the afternoon. Two 
small contained brush fires where observed from 
the roof deck at both 10:00 A.M. and 1:00 P.M. 

Today's Observations:

7 A.M.
Weather: Clear, few cirrostratus along the horizon in 
all directions
Temperature: 48F; Dew Point: 19F; Wind: NNE at 5 kts,
Wind: Light 
Sea-level pressure: 30.49 ins. Hg, rising, then more slowly     
Visibility: 75 miles
6-hr Max temp: 48F
6-hr Min temp: 40F
24-hr precip: 0.00 ins. 
24-hr snowfall: 0.0 ins.  
Snow depth: 0 ins. 
BHO SA 1155 CLR 75 326/48/19/0305/049/ FEW CS AND THN K LYR 
ALNG HRZN ALQDS WND LGT/ 8/005 51017 10048 20040

10 A.M.
Weather: Clear, few cirrostratus along the horizon in 
all directions, two small brush fires approximately 
5 miles SSW and 25 mile W.
Temperature: 56F; Dew Point: 16F; Wind: N at 6 kts,
Wind: Light
Sea-level pressure: 30.50 ins. Hg, rising then steady
Visibility: 75 miles
3-hr precip: 0.00 ins. 
3-hr snowfall: 0.0 ins. 
BHO SA 1455 CLR 75 330/56/16/3606/050/ FEW CS ALNG HRZN 
ALQDS SML BRUSH FIRES ESTMTD 5 MI SSW AND 25 MI W WND LGT/ 
8/005 50004 

1 P.M.
Weather:Clear, few cirrostratus/cirrus in all directions 
two small brush fires ~5 miles SSW and 25 miles W
Temperature: 61F; Dew Point: 14F; Wind: NE at 7 kts
Sea-level pressure: 30.46 ins. Hg, falling steadily 
Visibility: 80 miles 
6-hr Max temp: 60F
6-hr Min temp: 48F
6-hr precip: 0.00 ins. 
6-hr snowfall: 0.00 ins.   
Snow depth: 0 ins.
BHO SA 1755 CLR 80 314/61/14/0507/046/ FEW CI/CS ALQDS 
SML BRUSH FIRE ESTMTD 5 MI SSW AND 25 MI W/ 8/006 56016 
10062 20048

SUMMARY FOR SUNDAY, APRIL 22, 2018

TEMPERATURE (DEGREES F)
MAX.....61   NORMAL.....58
MIN.....36   NORMAL.....40
MEAN....49   NORMAL.....49

DEPARTURE FROM 30-YEAR NORMAL............................0
TOTAL DEPARTURE FOR THE MONTH..........................-95 [-4.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............16   DEPARTURE...........0
TOTAL HEATING UNITS FOR THE MONTH............531   DEPARTURE.........+94
TOTAL HEATING UNITS FOR THE SEASON..........5589   DEPARTURE........-332
TOTAL HEATING UNITS LAST SEASON TO DATE.....5260   DIFFERENCE.......+329

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................25 NW AT 12:39 P.M.  
                   AERO........................24 NW AT 12:39 P.M. 
                   ASOS........................26 NW AT 12:40 P.M.
                   DAVIS.......................25 M  AT 12:57 P.M.** RMY 26
FASTEST MILE FOR YESTERDAY.....................17 NW AT 12:41 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................17 NW AT  1:22 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................18 M  AT 12:42 P.M.**
AVERAGE WIND SPEED AND DIRECTION..............8.8 NW
                   ASOS.......................9.3
                   DAVIS......................8.6 M **
** Davis direction malfunctioning 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.14
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........4.32  DEPARTURE......+0.83
                         ASOS..............4.48  
TOTAL PRECIPITATION FOR THE YEAR..........23.12  DEPARTURE......+5.81
                         ASOS.............24.72

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE........-0.1
TOTAL SNOWFALL FOR THE MONTH................2.6  DEPARTURE........-0.2
TOTAL SNOWFALL FOR THE SEASON..............92.8  DEPARTURE.......+30.2

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
*   : Estimated data 

4/01 58/33/46/+5/0.00/0.0/336/44   45 SSW AERO 43 SSW RMY N/A  
4/02 38/30/34/-7/0.13/1.6/077/10   20 SSW AERO 15 SSW RMY 17
4/03 48/30/39/-3/..../0.0/238/31   28 SSE AERO 25 SSE RMY 25
4/04 54/36/45/+3/..../0.0/000/00   56 WNW AERO 56 WNW RMY 54
4/05 40/27/34/-9/0.00/0.0/760/98   53 WNW AERO 53 WNW RMY 52 
4/06 41/25/33/-10/0.25/1.0/156/20  37 S   AERO 36 S   RMY 38
4/07 46/32/35/-4/0.00/0.0/312/40   32 WNW AERO 35 WNW RMY 34
4/08 41/29/35/-9/0.00/0.0/290/37   35 WNW*AERO 31 WNW RMY 34
4/09 45/24/35/-9/0.00/0.0/715/01   28 WNW*AERO 25 WNW RMY 29
4/10 39/31/35/-10/T/T/000/00       14 SSW AERO 13 SSW RMY N/A
4/11 48/29/39/-6/T/0.0/364/46      24 SSE AERO 23 SSE RMY 25 
4/12 61/33/47/+2/0.03/0.0/.../..   39 SSW AERO 38 SSW RMY 41 
4/13 65/47/56/+10/T/0.0/.../..     37 SSW AERO 37 SSW RMY N/A
4/14 51/36/44/-2/0.00/0.0/.../..   33 ENE AERO 31 ENE RMY N/A
4/15 36/30/33/-14/..../T/.../..    39 ENE AERO 39 ENE RMY N/A
4/16 55/32/44/-3/..../.../..       41 ENE AERO 43 ENE RMY 41
4/17 48/36/42/-5/0.00/0.0/.../..   37 W   AERO 33 W   RMY 37
4/18 53/32/43/-5/..../0.0/.../..   35 W   AERO 31 W   RMY 34
4/19 41/34/38/-10/0.22/T/.../..    28 WNW AERO 25 WNW RMY N/A 
4/20 52/31/42/-7/0.00/0.0/.../..   34 NW  AERO 33 NW  RMY 36
4/21 60/33/47/-2/0.00/0.0/.../..   28 NW  AERO 26 NW  RMY 29
4/22 61/36/49/0/0.00/0.0/.../..    25 NW  AERO 24 NW  RMY 26 

4/23 Low temp since midnight is 40F; normal low is now 41F

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

RECORDS FOR APRIL 23
HIGH 85 IN 1908, 2007 
LOW 25 IN 1933,1989
PRECIP 1.99 IN. IN 2012
SNOWFALL 2.0 IN. IN 2012
PEAK GUST 64 MPH WNW IN 1962

RECORDS FOR APRIL 24
HIGH 82 IN 2001
LOW 22 IN 1930
PRECIP 2.51 INS IN 1898
SNOWFALL 1.2 INS IN 1967
PEAK GUST 59 MPH NW IN 1962

TODAY'S REPORT PREPARED BY: K.Geagan