BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 12, 2007   
ALL TIMES ARE IN EASTERN STANDARD TIME

COOLER TEMPERATURES TODAY AFTER THUNDERSTORM ON FRIDAY...
FILTERED SUNSHINE WITH GOOD VISIBILITY AGAIN TODAY...
A thundershower on Friday morning added just 0.02 inch
to the monthly total rainfall, which now stands at just
0.08 inch. Cooler temperatures and drier air returned
overnight with the high for the day of 63 occurring 
before sunrise.  The daytime high so far is 59 degrees.
Through the high thin cirrus, a partial halo has been
visible since mid-morning. The northeast wind this
afternoon is carrying smoke from a brush fire in Quincy
toward the Observatory and noticeably lowering the 
visibility in the W-NE directions. 

Today's observations:

7 A.M.   
Weather: Overcast stratocumulus, with breaks N-SE
Temperature: 55F, Dew point: 40F, Wind: NNE at 12G22 kts 
Sea-level pressure: 30.02 inches Hg, rising
Visibility: 70 miles  
6-hour min. 55 deg. 
BHO SA 1155 E35 BKN 45 OVC 70 166/55/40/0312G22/002/ BINOVC 
N-SE HIR CLDS VSB DSNT NE-ESE FEW LWR SC WND 00V06/ 8/501 
53030 70002 10063 20055

10 A.M.
Weather: Scattered stratocumulus, thin overcast cirrus
partial halo
Temperature: 55F, Dew point: 39F, Wind: NE at 14 kts
Sea-level pressure: 30.06 Hg, rising   
Visibility: 75 miles  
BHO SA 1455 E35 SCT 200 –OVC 75 180/55/39/0414/006/ FEW LWR 
DNS CI PARTIAL HALO WND 01V07 PK WND 0426/18/ 8/501 53014

1 P.M. 
Weather: Overcast cirrus and cirrostratus, partial halo,
smoke obscuring visibility from W-NE (from brush fire to NE)
Temperature: 58F, Dew point: 38F, Wind: ENE at 10 kts
Sea-level pressure: 30.03 Hg, falling   
Visibility: 75 miles, 55 miles W-NW 
BHO SA 1755 250 OVC 75 170/58/38/0710/003/ FEW LWR DNS CI 
THN SPTS IOVC ALQDS BINOVC DSNT E-SE FEW SML CU N PARTIAL HALO 
THN K OVHD-W-NW DNS K LYR ABV HRZN N-NE VSBY W-WNW 55 WND 04V10/ 
8/107 56010 10059 20054

 
WEATHER SUMMARY FOR FRIDAY, MAY 11 

TEMPERATURE (DEGREES F)
MAX.....74    NORMAL.....65 
MIN.....60    NORMAL.....45
MEAN....67    NORMAL.....55
DEPARTURE FROM 30-YEAR NORMAL..........+12
TOTAL DEPARTURE FOR THE MONTH..........+57 (+5.0 DEGREES/DAY)
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............0  DEPARTURE........-10
TOTAL HEATING UNITS FOR THE MONTH...........83  DEPARTURE........-45 
TOTAL HEATING UNITS FOR THE SEASON........5699  DEPARTURE.......-455
TOTAL HEATING UNITS LAST SEASON TO DATE...5554  DIFFERENCE......+145 

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............23  S  AT  9:48 A.M. *
                   AEROVANE.............23  S  AT  9:29 A.M. *
                   ASOS.................23  S  AT  9:43 A.M.
                   DAVIS................N/A
FASTEST MILE FOR YESTERDAY..............18  S  AT  9:45 A.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE...........20  S  AT  9:47 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..........19  S  AT  9:15 A.M.
AVERAGE WIND SPEED AND DIRECTION.......11.0 S
                    ASOS...............10.8   
                    DAVIS...............9.7 S [190 degrees] 
* last of several occurrences...
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.02   DEPARTURE....-0.10
                         ASOS..............0.02
TOTAL PRECIPITATION FOR THE MONTH..........0.08   DEPARTURE....-1.29 
                         ASOS..............0.06    
TOTAL PRECIPITATION FOR THE YEAR..........20.50   DEPARTURE....+1.18
                         ASOS.............20.03    
 
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......-0.1 
TOTAL SNOWFALL FOR THE SEASON..............27.6  DEPARTURE.....-32.5  
    
PRELIMINARY CLIMATE SUMMARY FOR MAY 2007......CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST

AERO: Aerovane recording wind system when significant
TSTM: Thunderstorm day
....: Data not yet available
 
5/1  67/44/56/+4/0/0/624/74      33 NW 
5/2  64/45/55/+3/0.06/0/381/45   36 NW    Aero 33 MPH WNW
5/3  67/42/55/+2/0/0/849/100     38 W     Aero 37 MPH W
5/4  66/44/55/+2/0/0/842/99      39 WNW   Aero 40 MPH WNW 
5/5  65/45/55/+2/0/0/384/45      33 N  
5/6  51/42/47/-7/T/0/514/60      36 N     Aero 33 MPH N 
5/7  68/39/54/0/0/0/798/93       25 S
5/8  77/43/60/+6/0/0/851/99      33 S     Aero 31 MPH S 
5/9  85/54/70/+15/0/0/707/92     30 S 
5/10 85/60/73/+18/0/0/692/80     29 S     Aero 27 MPH S
5/11 74/60/67/+12/0.02/0/.../..  23 S

5/12  morning low temp. 55 deg.; normal now 45 deg.    
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):

RECORDS FOR MAY 12
HIGH 88F IN 2001
LOW 29F IN 1907
PRECIP 1.49 INCHES IN 1968
PEAK GUST 76 MPH S IN 1974

RECORDS FOR MAY 13
HIGH 85F IN 1947
LOW 35F IN 1914, 2005
PRECIP 2.39 INCHES IN 2006
PEAK GUST 49 MPH NNW IN 1965

TODAY'S REPORT PREPARED By: Mike Iacono

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