BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, OCTOBER 21, 2008 
ALL TIMES ARE IN EASTERN STANDARD TIME UNLESS NOTED
 
MIDDLE CLOUD LAYERS WITH PRECIPITATION ALOFT (VIRGA)
EARLY MORNING LOW TEMPERATURE A RELATIVELY MILD 43F
OCTOBER SUNSHINE AT 65% IS WELL ABOVE AVERAGE
 
A mostly overcast sky prevailed today with lots of
precipitation or virga trailing from the clouds
into very dry air near the surface. We had a good
view of virga trails and a classic display in the
form of mammatus early this afternoon.
 
An overnight temperature inversion resulted in near
or below freezing conditions below the summit while
our low of 43F was 9 degrees warmer than the 34F
just yesterday morning here at the summit.
 
Another very sunny day yesterday makes a total of
six days this month with 90% or more of the possible
bright sunshine and leaves the month with 65% of the
possible sunshine well above the long-term average
of 55%.
 
Today's observations:
 
8 A.M. EDT
Weather: Scattered altocumulus, variety is chaotic, patches
of dense cirrus with trailing snow virga, thin higher overcast
of cirrus with breaks in the overcast 
Temperature: 49F, Dew point: 24F,  Wind: WSW at 7 kts,
Sea-level pressure: 29.93 inches, falling
Visibility: 50 miles, inversion present with few patches of
thin ground fog dissipating past hour  
6-hourly minimum temperature: 43F
24-hourly rainfall: 0.00
BHO SA 1155 130 SCT 150 SCT 200 SCT 250 –BKN 300 –OVC
50 136/49/24/2407/993/ AC CHAOTIC PTCHS DENS CI TRLS SNW VIRGA/
BINOVC INVSN PRSNT FEW PTCHS THN GF DSSPTG GF BLO INVSN/
8/092 58009 10049 20043
 
11 A.M. EDT
Weather: Overcast with numerous breaks in the overcast
with two layers of altocumulus, considerable snow virga
and plain virga trailing from clouds, patches of alto-
cumulus castellanus and dense cirrus
Temperature: 55F, Dew point: 34F, Wind: S at 9 kts
Sea-level pressure: 29.91 inches Hg, falling
Visibility: 35 miles, thin smoke layer along horizons,
Visibility: WNW 50 miles 
BHO SA 1455 E130 BKN 180 OVC 35 128/55/34/1709/991/
ACC/PTHCS DENS CI SNW VIRGA/VIRGA ALQDS NMRS BINOVC
THN K LYR ALG HRZNS VSBY WNW 50/ 8/082 58008
 
2 P.M. EDT
Weather: Overcast altocumulus with virga, break in
overcast overhead through southwest, virga mammatus
observed past hour     
Temperature: 58F, Dew point: 37F, Wind: S at 6 kts,
Sea-level pressure: 29.83 inches Hg, falling
Visibility: 20 miles, haze increasing
6-hourly maximum temperature: 59F
BHO SA 1755 E90 OVC 20 101/58/37/1706/983/
BINOVC OVHD-SW VIRGA ALQDS VIRGA MAMMATUS
PST HR HZ INCRSNG/ 8/07/ 58027 10059 20049
 
WEATHER SUMMARY FOR MONDAY, OCTOBER 20
 
TEMPERATURE (DEGREES F)
MAX.....54    NORMAL.....59
MIN.....34    NORMAL.....42
MEAN....44    NORMAL.....50
 
DEPARTURE FROM 30-YEAR NORMAL.............-6
TOTAL DEPARTURE FOR THE MONTH............+11 (+0.4 DEGREES/DAY)
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............21  DEPARTURE........+6
TOTAL HEATING UNITS FOR THE MONTH...........221  DEPARTURE.......-16
TOTAL HEATING UNITS FOR THE SEASON......... 337  DEPARTURE.......-69
TOTAL HEATING UNITS LAST SEASON TO DATE.... 230  DIFFERENCE.....+107
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............25  N  AT  8:28 A.M. *
                   AEROVANE.............23 NNW AT  6:45 A.M.  
                   ASOS.................24 NNW AT  6:45 A.M. 
                   DAVIS................26 NNW AT  6:44 A.M. 
FASTEST MILE FOR YESTERDAY..............18  NW AT  5:00 A.M.  
MAXIMUM 2-MINUTE ASOS AVERAGE...........17 NNW AT  6:12 A.M. 
MAXIMUM 2-MINUTE DAVIS AVERAGE..........18  NW AT  4:56 A.M. 
                   AVERAGE............ 9.3 NNW
                   ASOS................9.2
                   DAVIS...............9.5 NNW [330 deg]
* Last of several occurrences
 
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..........0.63   DEPARTURE.......-2.17
                         ASOS..............0.63
TOTAL PRECIPITATION FOR THE YEAR..........43.53   DEPARTURE.......+3.11
                         ASOS.............46.11 #
#  Includes erroneous ASOS precipitation data on 2/13/08.
 
PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 2008 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/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
 
10/1  68/58/63/+6/0.49/120/17     38 SW   TSTM #
10/2  62/46/54/-2/0.12/455/65     45 W
10/3  62/45/54/-2/T/376/54        44 SSW  Aero 43 MPH SSW
10/4  61/40/51/-5/0.00/612/88     32 WSW
10/5  53/45/49/-6/T/000/00        18 WNW
10/6  58/39/49/-6/0.00/303/44     28 WNW
10/7  64/37/51/-4/0.00/687/100    23 WNW
10/8  69/43/56/+2/0.00/581/85     32 S    Aero 30 MPH S
10/9  72/55/64/+10/0.02/510/75    33 WSW 
10/10 69/53/61/+7/0.00/664/98     29 W
10/11 68/49/59/+6/0.00/668/99     20 NNW
10/12 67/47/57/+4/0.00/625/93     21 W
10/13 62/50/56/+4/0.00/308/46     20 NE
10/14 65/50/58/+6/0.00/514/77     30 SSE
10/15 64/52/58/+6/0.00/618/93     21 ENE  
10/16 67/51/59/+8/T/026/04        35 NW
10/17 59/42/51/0/0.00/474/72      26 NW
10/18 51/37/44/-7/0.00/440/67     25 N
10/19 46/36/41/-10/0.00/176/27    36 NNE  Aero 36 MPH NNE
10/20 54/34/44/-6/0.00/631/97     25 N 
 
10/21 morning low temp. 43F; our normal low is now 41F
 
# Thunderstorm gust 
 
NEW DAILY RECORDS FOR OCTOBER
 
None...
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR OCTOBER 21
HIGH 79 IN 1979
LOW 24 IN 1974
PRECIP 2.39 INCHES IN 1944
SNOWFALL TRACE IN 1895,1907,1940
PEAK GUST 69e MPH S IN 1976
 
RECORDS FOR OCTOBER 22
HIGH 85 IN 1979
LOW 22 IN 1940
PRECIP 1.37 INCHES IN 1898
SNOWFALL TRACE IN 1969
PEAK GUST 67 MPH ESE IN 1988
 
TODAY'S REPORT PREPARED By: Robert Skilling