BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, MARCH 23, 2009
ALL TIMES ARE IN EASTERN STANDARD TIME 
 
ARRIVAL OF MUCH COLDER ARCTIC AIRMASS
GUSTY WNW-NW WINDS OVER 30 MPH AT TIMES
 
As the much colder air was arriving aloft
yesterday the instability of the airmass
created lots of virga.  Some of this precip-
itation hanging from the clouds made it to
the ground in the form of light rain and snow
showers.  None was observed here but a few
places locally had a few snow flakes. Much colder
and drier air made it to the surface last evening
when dew points dropped rapidly from the upper
20's in the early evening to near zero by
midnight.  Gusty west-northwest to northwest
winds reached speeds of 30 to 35 MPH today
and temperatures were struggling into the
low 30's up from a morning low of 21F. The
normal maximum temperature for today is 47F.
The temperature had briefly touched the 32-degree
mark early this afternoon but the dew point had
dropped to 4 below zero F. 
 
Today's observations:
 
7 A.M.
Weather: Clear, few stratocumulus forming NW-NE-SE
Temperature: 23F, Dew point: 6F, Wind: WNW at 11G20 kts,
Wind: direction variable W-NNW 
Sea-level pressure: 30.27 inches Hg, falling
Visibility: 60 miles
6-hour minimum temperature: 21F
24-hour precipitation: 0 inches
BHO SA 1155 CLR 60 250/23/6/3011G20/027/ WND 27V33
FEW SC FRMG NW-NE-SE/ 8/500 50004 10026 20021
 
10 A.M.
Weather: Clear, few mostly distant stratocumulus
Temperature: 26F, Dew point: -2F, Wind: NW at 17G24 kts,
Wind: direction variable W-N
Sea-level pressure: 30.25 inches Hg, falling
Visibility: 70 miles
BHO SA 1455 CLR 70 242/26/-2/3117G24/025/
FEW MSTLY DSNT SC ALQDS WND 28V35/ 8/500 58008
 
1 P.M.  
Weather: Clear, cumulus all quadrants, snow virga trails  
Temperature: 30F, Dew point: -4F, Wind: NW at 14G24 kts,
Wind: Peak wind 26 kts NNW @ 12:32 P.M.
Wind: direction variability WNW-N
Sea-level pressure: 30.20 inches Hg, falling
Visibility: 75 miles
6-hour maximum temperature: 32F 
BHO SA 1755 CLR 75 226/30/-4/3214G24/020/
CU ALQDS SNW VIRGA TRLS PK WND 3326/32/
WND 29V36/ 8/100 58016 10032 20023
 
WEATHER SUMMARY FOR SUNDAY, MARCH 22, 2009
 
TEMPERATURE (DEGREES F)
MAX.....50    NORMAL.....47
MIN.....27    NORMAL.....30
MEAN....39    NORMAL.....38
 
DEPARTURE FROM 30-YEAR NORMAL..................+1
TOTAL DEPARTURE FOR THE MONTH...................0  [-0.2 DEGREES/DAY] 
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY.............26  DEPARTURE.........-1
TOTAL HEATING UNITS FOR THE MONTH............662  DEPARTURE.........-4
TOTAL HEATING UNITS FOR THE SEASON..........5189  DEPARTURE........-47
TOTAL HEATING UNITS LAST SEASON TO DATE.....4879  DIFFERENCE......+310
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............29 NW  AT 11:04 P.M. *
                   AEROVANE.............31 WNW AT  4:28 P.M.
                   ASOS.................31 NW  AT 11:04 P.M.
                   DAVIS................33 WNW AT  4:30 P.M.
FASTEST MILE FOR YESTERDAY..............24 WNW AT  4:33 P.M. * 
MAXIMUM 2-MINUTE ASOS AVERAGE...........23 NW  AT  4:33 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..........25 WNW AT  4:33 P.M.
                   AVERAGE............14.0 SSW
                   ASOS...............13.4
                   DAVIS..............13.8 WSW [250 DEGREES]
* last of several occurrences
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.....0.00 DEPARTURE.........-0.16 
                         ASOS...............0.00
TOTAL PRECIPITATION FOR THE MONTH...........2.45 DEPARTURE.........-0.94
                         ASOS...............2.39
TOTAL PRECIPITATION FOR THE YEAR............8.98 DEPARTURE.........-3.25
                         ASOS..............10.01 #
# Includes erroneous ASOS precipitation data on 1/1/09, 1/2/09 and 2/27/09.
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0   DEPARTURE.........-0.3
TOTAL SNOWFALL FOR THE MONTH...............13.4   DEPARTURE.........+4.2
TOTAL SNOWFALL FOR THE SEASON..............78.7   DEPARTURE........+24.1
 
PRELIMINARY CLIMATE SUMMARY FOR MARCH 2009 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane recording wind system gust when significant
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
3/1  28/21/25/-7/0.26/1.9/000/00     38 NNE
3/2  22/15/19/-13/1.21/8.2/000/00    40 NNE    AERO 37 MPH NNE
3/3  25/11/18/-14/0.01/0.1/640/94    33 NW
3/4  30/6/18/-14/0/0/684/100         31 WNW
3/5  39/16/28/-5/0/0/659/96          25 WSW
3/6  49/30/40/+7/T/0/152/22          43 S      AERO 41 MPH S
3/7  60/42/51/+18/0.06/0/429/62      37 S
3/8  57/42/50/+16/0/0/445/64         39 WNW    AERO 40 MPH WNW
3/9  42/28/35/+1/0.72/3.2/000/00     33 N
3/10 42/26/34/0/0.02/0/470/67        23 SSE
3/11 50/33/42/+7/0.13/0/000/00       51 W
3/12 39/25/32/-3/0/0/685/97          44 W      AERO 45 MPH W
3/13 37/19/28/-7/0/0/660/93          26 SSE
3/14 50/25/38/+2/0/0/613/86          24 SSW
3/15 59/34/47/+11/0/0/686/96         17 SSW
3/16 42/29/36/0/0/0/000/00           30 NE
3/17 47/28/38/0/+1/671/93            21 SSW   
3/18 59/31/45/+8/0/0/448/62          37 SSW    AERO 40 MPH S
3/19 45/36/41/+4/0.04/0/000/00       22 S     
3/20 36/25/31/-7/0/0/.../..          26 NNE
3/21 43/23/33/-5/0/0/.../..          21 S
3/22 50/27/39/+1/0/0/.../..          29 NW     AERO 31 MPH WNW   
 
3/23 morning low temp. 21F; our normal low now is 30F
 
NEW DAILY RECORDS FOR MARCH 2009...
3/2: DAILY SNOWFALL 8.2 INS. SURPASSES PREVIOUS
     RECORD OF 7.1 INS. IN 1948
3/7: DAILY MINIMUM 42 TIES RECORD HIGH MINIMUM FOR DATE
     PREVIOUSLY SET IN 1974 AND 1987
3/8: DAILY MINIMUM 42 TIES RECORD HIGH MINIMUM FOR DATE
     PREVIOUSLY SET IN 1995
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR MARCH 23
HIGH 78 IN 1938
LOW 3 IN 1934
PRE 1.58 INS. IN 1903
SNOW 3.0 INS. IN 1977
WIND 78e MPH W IN 1940
 
RECORDS FOR MARCH 24
HIGH 70 DEGREES IN 1920
LOW 6 DEGREES IN 1906
PRECIP 1.51 INS. IN 1956
SNOWFALL 12.3 INS. IN 1956
PEAK GUST 71 MPH W IN 1968
 
TODAY'S REPORT PREPARED BY: Robert Skilling