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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 26, 2007   
ALL TIMES ARE IN EASTERN STANDARD TIME

WARM AND PARTLY SUNNY TODAY WITH DRIER AIR RETURNING
THIS AFTERNOON...RECORD HIGH TEMPERATURE OF 91 ON FRIDAY...

Both the high and low temperatures were new records on
Friday, with 91 surpassing the record high of 89 in 1981
and the low of 66 breaking the record high minimum of
65 for the date in 1991.  The low temperature this morning
of 68 is well above the record high minimum for this date
of 63 set in 1981.  The dew point dropped sharply from
the mid-50s to about 40 degrees between 11 AM and 1 PM EDT
as drier air is mixing down to the surface. It is down to 
the mid-30s as of 2 PM EDT. As a result, the visibility has 
climbed from 10 miles early today to about 35 miles early 
this afternoon, and the relative humidity has dropped to 
18 percent. 

 
Today's observations:

7 A.M.   
Weather: Scattered altocumulus and thin overcast cirrus 
Temperature: 73F, Dew point: 60F, Wind: W at 13 kts 
Sea-level pressure: 30.05 ins. Hg, rising  
Visibility: 10 miles, hazy     
6-hour min temp. 68 deg.F 
BHO SA 1155 150 SCT 250 –OVC 10 175/73/60/2713/005/ HAZY 
WND 24V30/ 8/071 51007 10073 20068
   
10 A.M. 
Weather: Scattered altocumulus and thin overcast cirrus
Temperature: 79F, Dew point: 57F, Wind: W at 11 kts 
Sea-level pressure: 30.04 ins. Hg, falling  
Visibility: 20 miles, hazy     
BHO SA 1455 100 SCT 150 SCT 250 –OVC 20 172/79/57/2611/004/ 
HAZY/ 8/071 58003

1 P.M. 
Weather: Scattered altocumulus and thin overcast cirrus
Temperature: 84F, Dew point: 36F, Wind: W at 10 kts 
Sea-level pressure: 30.02 ins. Hg, falling  
Visibility: 35 miles, hazy     
6-hour max temp. 85 deg.F
BHO SA 1755 120 SCT 250 –OVC 35 165/84/36/2710/002/ FEW LWR 
DNS CI HAZY PK WND 2726/12 WND 23V31/ 8/071 58007 10085 20073

WEATHER SUMMARY FOR FRIDAY, MAY 25  

TEMPERATURE (DEGREES F)
MAX.....91    NORMAL.....70 
MIN.....66    NORMAL.....50
MEAN....79    NORMAL.....60
DEPARTURE FROM 30-YEAR NORMAL..........+19
TOTAL DEPARTURE FOR THE MONTH..........+44 (+1.6 DEGREES/DAY)
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............0  DEPARTURE.........-6
TOTAL HEATING UNITS FOR THE MONTH..........212  DEPARTURE........-26  
TOTAL HEATING UNITS FOR THE SEASON........5828  DEPARTURE.......-436
TOTAL HEATING UNITS LAST SEASON TO DATE...5711  DIFFERENCE......+117  

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............24 W AT  7:07 A.M.  
                   AEROVANE.............22 W AT  7:07 A.M. 
                   ASOS.................23 W AT 12:48 A.M. ** 
                   DAVIS................N/A   
FASTEST MILE FOR YESTERDAY..............18 W AT 12:47 A.M.   
MAXIMUM 2-MINUTE ASOS AVERAGE...........17 W AT  9:22 P.M. **  
MAXIMUM 2-MINUTE DAVIS AVERAGE..........19 W AT  9:22 P.M.   
AVERAGE WIND SPEED AND DIRECTION........12.3 W
                   ASOS.................11.8 **  
                   DAVIS................12.4 W [266]

** new ASOS wind system [ULTRASONIC] installed on 25 May. 
 
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..........3.71  DEPARTURE.....+0.66 
                         ASOS..............3.64    
TOTAL PRECIPITATION FOR THE YEAR..........24.13  DEPARTURE.....+3.13
                         ASOS.............23.61    
 
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/+12/0.02/0/355/41  23 S     TSTM A.M.  
5/12 63/47/55/-1/0.02/0/469/54   32 NE    
5/13 65/46/56/0/T/0/775/89       33 WNW   Aero 33 MPH WNW 
5/14 73/43/58/+1/0/0/822/94      30 SSW
5/15 80/50/65/+8/0.01/0/210/24   30 S     TSTM evening   
5/16 66/44/55/-2/0.54/0/527/60   40 NW    TSTM P.M.  
5/17 50/42/46/-11/0.01/0/009/01  28 NE  
5/18 42/39/41/-17/1.93/0/000/00  37 NNE
5/19 51/40/46/-12/0.71/0/000/00  25 NNW
5/20 59/49/54/-4/0.41/0/035/04   30 W     TSTM P.M.  
5/21 63/46/55/-4/0/0/693/78      29 WNW
5/22 71/46/59/0/0/0/800/90       25 SSE  
5/23 74/47/61/0/0/757/85         30 SSE 
5/24 86/50/68/+8/0/0/.../..      25 WSW
5/25 91/66/79/+19/0/0/.../..     24 W

5/26 morning low temp. 68 deg; normal low now 50 deg.  

NEW DAILY RECORDS FOR MAY:

5/18 Record low maximum temperature, 42; previous 48 in 1895 and 1956.
5/18 Record daily precipitation, 1.93; previous 1.58 inches in 2002.
5/25 Record high maximum temperature, 91; previous 89 in 1981.
5/25 Record high minimum temperature, 66; previous 65 in 1991.

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

RECORDS FOR MAY 26
HIGH 89F IN 1914,1965
LOW 37F IN 1972
PRECIP 1.73 INS IN 2003
SNOWFALL TRACE IN 1967 (Fell as ice pellets in nor'easter)
PEAK GUST 62 MPH NE IN 1967

RECORDS FOR MAY 27
HIGH 92F IN 1914
LOW 36F IN 1915
PRECIP 1.40 INS IN 1898
PEAK GUST 55 S IN 1956

TODAY'S REPORT PREPARED By: Mike Iacono 

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