Friday, December 6, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, DECEMBER 6, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

WARM START, FRONT PASSES, DROPPING TEMPERATURES THROUGH THE DAY;
OVERCAST WITH OCCASIONAL DRIZZLE AND LIGHT RAIN

The temperature steadily increased throughout the day yesterday until about
7-8 A.M. this morning, when the high temperature for the day of 55F was
reached. At about 8:15 A.M. a cold front came plowing through, shifting the
wind from SW to NW, and dropping the temperature. The temperature has
steadily declined since the morning frontal passage, and has fallen into
the mid 40s this afternoon.

Also with the front, there was a quick and dramatic change in sky conditions
and visibility. The day began with dense fog, reducing visibility to 1/16th
of a mile, that is, until the front came plowing through. The quick change
in air mass quickly dissipated the fog and the cloud base increased. At one
point it remained foggy as you looked to the east, while to the west the
visibility had increased to more than 50 miles.

Occasional drizzle and rain showers that began late yesterday morning have
continued into today, amounting to a total of 0.03 inch, with 0.02 inch of
that falling yesterday.

Today’s Observations:

7 A.M.
Weather: Sky obscured by dense fog and light drizzle, light drizzle
continued
Temperature: 54F; Dew Point: 54F; Wind: SW at 9 kts.
Sea-level pressure: 29.91 ins. Hg, falling then rising
Visibility: 1/16 mile, dense fog and light drizzle
24-hr precip: 0.02 inch
6-hr precip: Trace
6-hr min temp: 53F
BHO SA 1155 W3 X 1/16F 128/54/54/2209/991/ L- CTD/ 8//// 53005 MANUAL 70002
ASOS 70001 MANUAL 6000/ 10054 20053

10 A.M.
Weather: Light rain, scattered stratocumulus/cumulus, overcast nimbostratus,
lower stratocumulus/cumulus layer S-W-NNE, dark higher stratocumulus base
E-SW, light drizzle becoming light rain at unknown time and continuing
light and intermittent
Temperature: 49F; Dew Point: 48F; Wind: NNW at 8 kts.
Sea-level pressure: 29.97 ins. Hg, rising then rising more slowly
Visibility: 15 miles, NE 25 miles, SE-S 6 miles, WNW 20 miles, light rain
3-hr precip: Trace
BHO SA 1455 5 SCT E30 OVC 15R- 149/49/48/3408/997/ LWR SC/CU S-W-NNE DRK
HIER SC BASE E-SW VSBY NE 25 SE-S 6 WNW 20 L- BCMG R- UKN CTD LGT AND
INTMT/ 8/8// 51021 MANUAL 6000/

1 P.M.
Weather: Light rain shower, broken stratocumulus (2 levels), overcast
nimbostratus, few stratocumulus lenticularis ENE-SE, rain shower WSW-WNW
moving ENE, light rain shower began at 12:54 P.M. EST and continued light
Temperature: 47F; Dew Point: 44F; Wind: NW at 10 kts.
Sea-level pressure: 29.97 ins. Hg, rising then falling
Visibility: 35 miles, WSW-WNW 15 miles, NW-NE 60 miles, light rain shower
6-hr. max temp. 55F
6-hr precip: 0.01 in.
BHO SA 1755 E10 BKN 25 BKN 40 OVC 35RW- 150/47/44/3210/997/ FEW SCSL ENE-SE
SHRA WSW-WNW MOVG ENE VSBY WSW-WNW 15 NW-NE 60 RW-B54 CTD LGT/ 8/8// 51001
MANUAL 60001 ASOS 60001 10055 20047

WEATHER SUMMARY FOR THURSDAY, DECEMBER 5, 2013

TEMPERATURE (DEGREES F)
MAX…..53 NORMAL…..43
MIN…..38 NORMAL…..27
MEAN….46 NORMAL…..35

DEPARTURE FROM 30-YEAR NORMAL…………………+11
TOTAL DEPARTURE FOR THE MONTH…………………+16 [+3.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..19 DEPARTURE……..-11
TOTAL HEATING UNITS FOR THE MONTH………….130 DEPARTURE……..-16
TOTAL HEATING UNITS FOR THE SEASON………..1354 DEPARTURE……..-54
TOTAL HEATING UNITS LAST SEASON TO DATE……1261 DIFFERENCE…….+93

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………36 S AT 10:22 P.M.
AERO…………………..40 S AT 10:22 P.M.
ASOS…………………..40 S AT 10:22 P.M.
DAVIS………………….37 S AT 10:21 P.M. RMY 39
FASTEST MILE FOR YESTERDAY………………..27 S AT 10:47 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE……………..29 S AT 10:48 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….27 S AT 10:48 P.M.
AVERAGE WIND SPEED AND DIRECTION…………12.5 SSE
ASOS…………………12.9
DAVIS………………..11.6 SSE [163 degrees] * last of several occurrences…

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.02 DEPARTURE………….-0.15
ASOS…………..0.01
TOTAL PRECIPITATION FOR THE MONTH……….0.30 DEPARTURE………….-0.52
ASOS…………..0.29
TOTAL PRECIPITATION FOR THE YEAR……….46.90 DEPARTURE………….-2.45
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………….-0.3
TOTAL SNOWFALL FOR THE MONTH………..Trace DEPARTURE………….-1.4
TOTAL SNOWFALL FOR THE SEASON…………0.2 DEPARTURE………….-3.8

PRELIMINARY CLIMATE SUMMARY FOR DECENBER 2013 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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

12/1 45/30/38/+1/0.28/T/000/00 22 SSE AERO 23 MPH SSE RMY 23
12/2 38/34/36/0/T/0.0/000/00 15 NW AERO 15 MPH NW RMY N/A
12/3 45/32/39/+3/0.00/0.0/…/.. 18 NNW AERO 18 MPH NNW RMY 20
12/4 43/29/36/+1/0.00/0.0/…/.. 21 WNW AERO 21 MPH WNW RMY 21
12/5 53/38/46/+11/…./0.0/000/00 36 S AERO 40 MPH S RMY 39

12/6 morning low temp since midnight: 53F; the normal low is now 27F

DAILY RECORDS FOR DECEMBER 2013
None so far.

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

RECORDS FOR DECEMBER 6
HIGH 70 IN 2001
LOW 5 IN 1901,1935
PRECIP 2.78 INS. IN 2003
SNOWFALL 17.0 INS. IN 2003
PEAK GUST 74 MPH NW IN 1981

RECORDS FOR DECEMBER 7
HIGH 74 IN 1998
LOW 6 IN 1906
PRECIP 1.67 INS. IN 1953
SNOWFALL 6.3 INS. IN 2003
PEAK GUST 76e SE IN 1976

TODAY’S REPORT PREPARED BY: Sean Fankhauser