BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, JULY 20, 2009
ALL TIMES ARE IN EASTERN STANDARD TIME
 
TEMPERATURES REACHED THE 80'S OVER THE WEEKEND
AS SUNNY AND VERY PLEASANT WEATHER CONTINUED
THUNDERSTORM BROUGHT EARLY SATURDAY A.M. DOWNPOUR
 
Temperatures continued to reach the 80-degree
mark and above this weekend after the first
80-degree maximum temperature of the season
occurred last Friday, 17 July, at 86F, the
latest date on our entire record in summer to 
reach 80 degrees. Sunny, pleasantly warm weather
continued for a third consecutive July weekend
with high temperatures reaching 80F or more.
A thunderstorm early Saturday morning brought
a downpour which left 0.36 inch of rainfall,
one quarter inch of which fell in just 10
minutes ending at 2:40 a.m. EDT.
 
Today's observations:
 
7 A.M.  
Weather: Clear, patches of altocumulus and variety lenticularis,
few cirrus 
Temperature: 70F, Dew point: 58F, Wind: NNE at 6 kts,
Wind: direction gradually veering 
Sea-level pressure: 30.20 inches Hg, rising
Visibility: 50 miles, northwest 70 miles, northeast-southeast 30 miles
6-hour minimum temp: 64F
BHO SA 1155 CLR 50 228/70/58/0206/020/
PTCHS AC/ACSL/CI ALQDS VSBY NW 70 NE-SE 30
THN K LYR ALG HRZN W-N LGT HZ WND GRDLY VEERING/
8/041 53011 10070 20064
 
10 A.M.
Weather: Thin broken altocumulus and cirrus, altocumulus
chaotic variety 
Temperature: 77F, Dew point: 58F, Wind: NNE at 7 kts,
Wind: direction variability NNW to E 
Sea-level pressure: 30.22 inches Hg, steady
Visibility: 55 miles, northwest 70 miles, northeast-southeast 40 miles
BHO 1755 150 SCT 180 –BKN 250 –BKN 55 234/77/58/0307/022/
CU/MDT CU FRMG AC CHAOTIC VSBY NW 70 NE-SE 40 LGT HZ
WND 34V10/ 8/291 51006
 
1 P.M.  
Weather: Scattered altocumulus, variety chaotic, cumulus and
modt. cumulus except overhead thru NE-SE, dense cirrus,
overcast partly thin overhead thru north 
Temperature: 79F, Dew point: 59F, Wind: NNE at 7 kts,
Wind: direction variable N thru ENE 
Sea-level pressure: 30.22 inches Hg, rising
Visibility: 50 miles, 30 miles northeast thru southeast
6-hourly max. temp.  79F
BHO SA 1755 110 SCT E220 BKN 250 OVC 50 232/79/59/0307/022/
CU/MDT CU XCPT OVHD-NE-SE AC CHAOTIC DENS CI
OVC PTLY THN OVHD-N HZ INCRSNG VSBY NE-SE 30
WND 35V06/ 8/292 55004 10079 20070 
 
WEATHER SUMMARY FOR SUNDAY, JULY 19
 
TEMPERATURE (DEGREES F)
MAX.....80    NORMAL.....82
MIN.....62    NORMAL.....63
MEAN....71    NORMAL.....72
 
DEPARTURE FROM 30-YEAR AVERAGE..........-1
TOTAL DEPARTURE FOR THE MONTH..........-85  [-4.7 DEGREES/DAY]
 
HEATING DEGREE DATA WILL RESUME IN SEPTEMBER
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............27 WSW AT 10:17 A.M. 
                   AEROVANE..............23 WSW AT 10:17 A.M.  
                   ASOS..................25 WSW AT 10:18 A.M.   
                   DAVIS.................25 WSW AT 10:17 A.M.  
FASTEST MILE FOR YESTERDAY...............18 WSW AT 10:19 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE............18 WSW AT 10:19 A.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE...........18 WSW AT 10:19 A.M.  
AVERAGE WIND SPEED AND DIRECTION.......10.3 WSW
                   ASOS................10.3
                   DAVIS...............10.1 WSW [250 DEG]
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE....-0.12
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........3.45  DEPARTURE....+1.15
                         ASOS..............3.52 
TOTAL PRECIPITATION FOR THE YEAR..........27.09  DEPARTURE....-0.88
                         ASOS.............28.17
 
PRELIMINARY CLIMATE SUMMARY FOR JULY 2009 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust when significant
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
7/1  62/57/60/-10/0.51/000/00   25 NNE   TSTM
7/2  66/56/61/-9/1.00/000/00    29 SSW   TSTM
7/3  75/58/67/-3/T/283/31       23 WSW
7/4  77/59/68/-2/0/838/92       43 W      
7/5  78/54/66/-5/0/856/94       33 W     
7/6  79/60/70/-1/0/883/97       20 SSE
7/7  66/58/62/-9/0.73/027/03    28 SE    TSTM
7/8  67/56/62/-9/0.23/091/10    27 NNE   TSTM
7/9  66/55/61/-10/0/689/76      23 NE
7/10 76/54/65/-6/0/896/99       21 SW
7/11 77/56/67/-5/0.29/686/76    36 S
7/12 78/60/69/-3/0.33/650/72    30 SSW   TSTM
7/13 76/55/66/-6/0/802/89       32 SW 
7/14 75/56/66/-6/0/567/63       25 WNW
7/15 79/55/67/-5/0/826/92       30 WSW
7/16 77/62/70/-2/T/161/18       30 S
7/17 86/65/76/+4/0.01.../..     24 ESE
7/18 84/66/75/+3/0.35.../..     25 SSW   TSTM
7/19 80/62/71/-1/0/.../..       27 WSW
 
7/20 our morning low temp: 64F; the normal low is now 63F
 
NEW DAILY RECORDS FOR JULY 2009 TO DATE...
NONE
 
DAILY EXTREMES
 
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR JULY 20
HIGH 99F IN 1991
LOW 47F IN 1890
PRE 1.64 INS IN 1938
WIND 56e MPH SSW IN 1943
 
RECORDS FOR JULY 21
HIGH 100F IN 1977 [RECORD FOR MONTH]
LOW 48F IN 1890
PRECIP 2.09 INCHES IN 1938
PEAK GUST 60e MPH WNW IN 1977
 
TODAY'S REPORT PREPARED BY: Robert Skilling