SUNDAY, APRIL 7, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, APRIL 7, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

WARMER TEMPERATURES RETURN TODAY ON INCREASING SOUTH WIND

After a cooler than average day yesterday, warmer temperatures have
returned to the summit today, rebounding from a morning low of 31F to
the low 50s this afternoon, which is near normal. Altocumulus clouds have
been persistent today, allowing only occasional sunshine, which has kept
temperatures a bit lower than expected so far, though this could change.
Winds have been increasing from the S and SSW today, brining the milder
air with them. The peak gust observed so far today is 43mph. Visibility
has been moderate today, up to 65 miles at times, but haze has kept it
closer to 50 miles for much of the day.

April has gotten off to a cooler than average start, with the average
daily temperature running 1.5F below normal so far. Warm weather is
expected in the next few days which will likely erase this negative
departure and begin a positive departure. We are also running a rainfall
departure so far this month with no measurable precipitation recorded
since the 1st of the month. This continues a dry spell that began last
month, with less than a half inch of precipitation measured since March 20.

Today’s observations:

7 A.M.
Weather: Thin broken cirrus, few altocumulus SSW-NNE, haze layer aloft
Temperature: 36F; Dew Point: 27F; Wind: S at 12 kts,
Sea-level pressure: 30.32 ins. Hg, rising then rising more rapidly
Visibility: 45 miles, hazy
6-hour min. temp: 31F
BHO SA 1155 250 –BKN 45 269/36/27/1912/032/ FEW AC SSW-NNE
HAZY/HZ ALF 8/071 53014 10036 20031

10 A.M.
Weather: Broken altocumulus, broken cirrus (partly thin), few altocumulus
and altocumulus lenticularis NNW-NNE
Temperature: 46F; Dew Point: 20F; Wind: S at 17G24 kts,
Wind: Peak gust 32 kts, NW at 9:31 AM
Sea-level pressure: 30.27 ins. Hg, rising then falling
Visibility: 65 miles, except 55 miles NW, light distant haze
BHO SA 1455 E60 BKN 250 BKN 65 250/46/20/1917G24/027/ PK WND 1932/1431
250 LYR PRTLY THN FEW AC/ACSL NNW-NNE LT DSNT HZ VSBY NW 55 8/071 58019

1 P.M.
Weather: Broken altocumulus, few cumulus SSE-SSW, few lower altocumulus
and altocumulus lenticularis, few cirrus
Temperature: 52F; Dew Point: 28F; Wind: S at 25G34 kts,
Wind: Peak gust 34 kts, S at 1:49 PM
Wind: Direction variable SSE-WSW
Sea-level pressure: 30.15 ins. Hg, falling
Visibility: 50 miles, distant haze
6-hour max. temp: 52F
BHO SA 1755 E95 BKN 210/52/28/1925G34/015/ PK WND 1934/1749 FEW CU SSE-SSW
FEW LWR AC/ACSL FEW CI DSNT HZ WND 16V24 8/171 57040 10052 20031

WEATHER SUMMARY FOR SATURDAY, APRIL 6

TEMPERATURE (DEGREES F)
MAX…..47 NORMAL…..52
MIN…..30 NORMAL…..34
MEAN….39 NORMAL…..43

DEPARTURE FROM 30-YEAR NORMAL………………..-4
TOTAL DEPARTURE FOR THE MONTH………………..-8 [-1.5 DEGREE/DAY]

HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY…………26 DEPARTURE……….+4
TOTAL HEATING UNITS FOR THE MONTH………..146 DEPARTURE……….+8
TOTAL HEATING UNITS FOR THE SEASON………5166 DEPARTURE……..-456
TOTAL HEATING UNITS LAST SEASON TO DATE….4413 DIFFERENCE…….+753

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………38 NW AT 8:16 A.M.
AERO………………..35 NW AT 8:16 A.M. *
ASOS………………..39 NW AT 8:16 A.M.
DAVIS……………….38 NW AT 8:15 A.M. RMY: 40
THE FASTEST MILE FOR YESTERDAY………….29 NW AT 8:17 A.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE…………..29 NW AT 8:16 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………….29 NW AT 8:16 A.M.
AVERAGE WIND SPEED AND DIRECTION………13.5 NW
ASOS………………12.3
DAVIS……………..12.5 NW [310 deg] * Last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00 DEPARTURE………..-0.17
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….0.34 DEPARTURE………..-0.68
ASOS…………..0.35
TOTAL PRECIPITATION FOR THE YEAR……….14.43 DEPARTURE………..-0.59
ASOS…………..N/A*
*ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M………0.0 DEPARTURE…………-0.2
TOTAL SNOWFALL FOR THE MONTH………….Trace DEPARTURE…………-1.1
TOTAL SNOWFALL FOR THE SEASON………….99.0 DEPARTURE………..+38.2

PRELIMINARY CLIMATE SUMMARY FOR APRIL 2013 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust
RMY: RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized

4/1 61/31/46/+5/0.34/0.0/…/.. 40 W AERO 44 MPH WNW RMY 46
4/2 40/27/34/-7/T/T/…/.. 45 W AERO 42 MPH W RMY 47
4/3 45/27/36/-6/0.00/0.0/…/.. 44 W AERO 43 MPH W RMY 47
4/4 55/26/41/-1/0.00/0.0/…/.. 30 WSW AERO 27 MPH WSW RMY 31
4/5 59/36/48/+5/0.00/0.0/…/.. 33 NNW AERO 28 MPH NNW RMY 38
4/6 47/30/39/-4/0.00/0.0/…/.. 38 NW AERO 35 MPH NW RMY 40

4/7 morning low temp: 31F; the normal low is now 35F

DAILY RECORDS FOR APRIL 2013
None so far.

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

RECORDS FOR APRIL 7
HIGH 90 IN 2010
LOW 13 IN 1982
PRECIP 1.72 IN. IN 1924
SNOWFALL 4.5 IN. IN 1967, 1996
PEAK GUST 65 MPH WNW IN 1982

RECORDS FOR APRIL 8
HIGH 87 IN 1991
LOW 17 IN 1888
PRECIP 1.78 IN. IN 1956
SNOWFALL 9.3 IN. IN 1956
PEAK GUST 70 MPH S IN 2000

TODAY’S REPORT PREPARED BY: Jonathan O’Brien and Peter Volpe