Wednesday, May 20, 2015

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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, MAY 20, 2015
ALL TIMES ARE IN EASTERN STANDARD TIME

PARTLY SUNNY, SEASONABLY COOL, DRY AND BREEZY DAY
RAINFALL TOTALED 0.36 INCH YESTERDAY HERE BUT
WAS MUCH MORE TO OUR SOUTHEAST OVER CAPE COD
THUNDERSTORMS OVER WEST MA AND CT LAST EVENING

Today is partly sunny, seasonably cool and breezy
with temperatures slowly rising through the 60’s
as dew points remain in 40’s after rising to the
low 60’s late yesterday. A maximum temperature for
yesterday occurred at midnight last night. A wind
shift from south to west-northwest ushered much
drier and cooler air after the midnight hour.

Over 0.7 inch of rain fell over Cape Cod in the
rain yesterday while a much lighter third of an inch
was recorded locally.  Thunderstorms over western
Mass. and Ct. last evening weakened quickly before
reaching the local area.  Only a few drops of rain
fell here at the summit around 11:30 P.M. EDT
during last evening.

Today’s Observations:

7 A.M.
Weather: Thin broken cirrus, stratocumulus mostly distant S-W-N
Temperature: 55F; Dew Point: 43F; Wind: WNW at 12 kts
Sea-level pressure: 29.75 ins. Hg, rising then falling slightly
Visibility: 55 miles, distant haze
6-hr Max temp: 57F
6-hr Min temp: 50F
24-hr precip: 0.35 inches
BHO SA 1155 250 -BKN 55 076/55/43/3012/975/ SC MSTLY DSNT S-W-N
CI/PTCHS CC MSTLY ALQDS/ 8/509 50009 MANUAL 70035 ASOS 70036
10057 20050

10 A.M.
Weather: Broken stratocumulus, broken altocumulus lenticularis,
lenticularis overhead thru east and west, broken cirrus
Temperature: 61F; Dew Point: 43F; Wind: WNW at 14 kts
Sea-level pressure: 29.75 ins. Hg, steady
Visibility: 50 miles, except 30 miles NE, increasing distant haze
BHO SA 1455 E36 BKN 80 BKN 250 BKN 50 076/61/43/2914/975/
PTCH ACSL VC OVHD-E FEW ACSL W DSNT HZ INCR VSBY NE 30
8/541 50000

SUMMARY FOR TUESDAY, MAY 19, 2015

TEMPERATURE (DEGREES F)
MAX…..63   NORMAL…..67
MIN…..50   NORMAL…..48
MEAN….57   NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL……………………-1
TOTAL DEPARTURE FOR THE MONTH………………….+104 [+5.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………8  DEPARTURE…………0
TOTAL HEATING UNITS FOR THE MONTH…………..94  DEPARTURE……….-99
TOTAL HEATING UNITS FOR THE SEASON………..6365  DEPARTURE………+137
TOTAL HEATING UNITS LAST SEASON TO DATE……6298  DIFFERENCE………+67

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………..0   DEPARTURE……….-1
TOTAL COOLING UNITS FOR THE MONTH………….16   DEPARTURE……….+8
TOTAL COOLING UNITS FOR THE SEASON…………16   DEPARTURE……….+6
TOTAL COOLING UNITS LAST SEASON TO DATE…….13   DIFFERENCE………+3

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………24 S   AT  12:10 P.M.
ASOS…………………..26 S   AT  12:10 P.M. .
DAVIS………………….25 S   AT  12:10 P.M. RMY 26
FASTEST MILE FOR YESTERDAY………………..18 W   AT  11:46 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………..18 W   AT  11:46 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….17 S   AT   1:28 P.M.
AVERAGE WIND SPEED AND DIRECTION………….12.3 SSW
ASOS………………….12.8
DAVIS…………………11.4 SSW [200 deg.] * Last of several occurrences…

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…..0.35  DEPARTURE…..+0.21
ASOS……………0.36
TOTAL PRECIPITATION FOR THE MONTH………..0.63  DEPARTURE…..-1.72
ASOS……………0.63
TOTAL PRECIPITATION FOR THE YEAR………..18.55  DEPARTURE…..-2.22
ASOS…………….N/A ***
*** ASOS annual totals not available due to erroneous readings

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M………..0.0  DEPARTURE……0.0
TOTAL SNOWFALL FOR THE MONTH……………..0.0  DEPARTURE……0.0
TOTAL SNOWFALL FOR THE SEASON…………..150.8  DEPARTURE….+88.1

PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY 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

5/1  52/37/45/-8/0.00/0.0/354/42               21 NE  RMY 20
5/2  63/35/49/-4/0.00/0.0/668/79               20 S   RMY 20
5/3  74/44/59/+6/0.00/0.0/509/60               22 S   RMY 22
5/4  83/47/65/+11/0.00/0.0/783/92              39 SSW RMY 45
5/5  77/56/67/+13/0.03/0.0/222/26              29 SW  RMY N/A
5/6  74/54/64/+10/0.00/0.0/574/67              24 SSW RMY 25
5/7  84/52/68/+13/0.00/0.0/824/96              29 S   RMY 32
5/8  74/44/59/+4/0.00/0.0/809/94               27 NNE RMY 26
5/9  77/44/61/+6/0.00/0.0/509/59               30 S   RMY 32
5/10 88/60/74/+19/0.00/0.0/692/80              28 SSW RMY 30
5/11 84/48/66/+10/0.00/0.0/529/61              30 NE  RMY 31
5/12 84/47/66/+10/0.24/0.0/287/33              33 WNW RMY 37
5/13 67/47/57/+1/0.00/0.0/820/94               31 WNW RMY N/A
5/14 70/44/57/+0/0.00/0.0/…/..               22 NW  RMY 22
5/15 73/51/62/+5/0.00/0.0/…/..               20 WSW RMY 21
5/16 68/53/61/+4/T/0.0/…/..                  23 S   RMY 24
5/17 79/50/65/+8/T/0.0/…/..                  21 NE  RMY N/A
5/18 62/48/55/-3/…./0.0/…/..               25 NE  RMY N/A
5/19 63/50/57/-1/0.36/0.0/…/..               24 S   RMY 26

5/20 low since midnight is 50F; normal low is now 49F

DAILY RECORDS FOR MAY 2015

NONE SO FAR.

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

RECORDS FOR MAY 20
HIGH 91F IN 1975,1996
LOW 37F IN 1948, 2002
PRECIP 1.65 INCHES IN 1969
PEAK GUST 57 MPH S IN 1963, WNW IN 1982

RECORDS FOR MAY 21
HIGH 92F IN 1921
LOW 35F IN 1907
PRECIP 1.61 INS IN 1954
PEAK GUST 74 MPH WSW IN 2006

TODAY’S REPORT PREPARED BY: Robert Skilling