BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, APRIL 13, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME 0.16 INCH OF RAINFALL THURSDAY; TOTAL MONTHLY PRECIPITATION NEARLY DOUBLES Periodic rain showers that occurred from late morning through early evening on Thursday left 0.16 inch of rainfall on the summit. In and around Boston, rainfall totals in a few lucky spots nearly reached half of an inch. Some of the more intense showers even produced some small hail in the area, but not on the summit. This was our most substantial rainfall in nearly two weeks. The 0.16 inch of rain nearly doubled our monthly precipitation, pushing the total up to 0.34 inch, which is 1.70 inches below normal through April 12. The weather pattern across the region is finally in transition today. The upper level low which has dominated the weather pattern over the past several days is finally kicking out. That is bringing us warmer, drier, and sunnier conditions today. The warmth appears as though it will increase over the next few days, with temperatures expected to be well above average through the holiday weekend. The recent rainfall only provided for a very brief and temporary pause in the increasing rainfall deficit, which has now reached 9.61 inches. From March 4th through April 12th, a period of nearly 6 weeks, only 0.75 inch of precipitation has been observed on the summit. That's a mere 11% of the normal amount for this period. It's no wonder that severe drought conditions have developed across a large portion of southern New England. It was observed this morning that the small stream at the base of Great Blue Hill adjacent to the beginning of the summit road has essentially dried up. Not even a trickle of water can be seen flowing at this point in the stream bed. Substantial rainfall still does not appear to be looming anytime soon in the forecast ahead over the next week or so. Today's observations: 7 A.M. Weather: Scattered altocumulus, few altocumulus distant ENE-S and distant SW-WNW, few altocumulus castellanus distant SE-SSE and distant W, patches of valley fog WSW 10 miles and NW 1 mile, inversion dissipating, thin smoke layer along horizon all quadrants, light distant haze Temperature: 39F, Dew point: 34F, Wind: NW at 10 kts, Sea-level pressure: 30.14 inches Hg, rising Visibility: 75 miles, light distant haze 24-hour precip: 0.16 inch 6-hour min. temp: 36F BHO SA 1155 80 SCT 75 206/39/34/3210/014/ FEW AC DSNT ENE-S AND DSNT SW-WNW FEW ACC DSNT SE-SSE AND DSNT W PTCHS VLY FG WSW 10 AND NW 1 INVSN DSPTNG THN K LYR ALG HRZN ALQDS LGT DSNT HZ/ 8/080 52017 MANUAL 70016 ASOS 70014 10039 20036 10 A.M. Weather: Scattered cumulus, few moderate cumulus SW-NW-NNE, few cumulus fractus all quadrants except distant NE-ESE, mostly clear sky distant NE-ESE, light distant haze Temperature: 52F, Dew Point: 32F; Wind: NW at 7G13 kts, Wind: Direction variable W-N Sea-level pressure: 30.15 inches Hg, rising then falling Visibility: 75 miles, light distant haze BHO SA 1455 50 SCT 75 211/52/32/3107G13/015/ FEW MDT CU SW-NW-NNE FEW CUFRA ALQDS XCPT DSNT NE-ESE MSTLY CLR SKY DSNT NE-ESE LGT DSNT HZ WND 27V35/ 8/200 50005 1 P.M. Weather: Scattered cumulus, scattered thin cirrus, few moderate cumulus SE-SW-W, few cumulus fractus all quadrants except distant NE-ESE and distant NW-NNW, few thin cirrus distant N-NE, mostly clear sky distant NE-ESE and distant NW-NNW, light distant haze Temperature: 59F, Dew Point: 28F; Wind: W at 9G17 kts, Wind: Direction variable WSW-NW Sea-level pressure: 30.10 inches Hg, falling Visibility: 70 miles, light distant haze 6-hour max. temp: 60F BHO SA 1755 70 SCT 250 –SCT 70 193/59/28/2809G17/010/ FEW MDT CU SE-SW-W FEW CUFRA ALQDS XCPT DSNT NE-ESE AND DSNT NW-NNW FEW THN CI DSNT N-NE MSTLY CLR SKY DSNT NE-ESE AND DSNT NW-NNW LGT DSNT HZ WND 24V32/ 8/201 58018 10060 20039 WEATHER SUMMARY FOR THURSDAY, APRIL 12 TEMPERATURE (DEGREES F) MAX.....54 NORMAL.....54 MIN.....39 NORMAL.....36 MEAN....47 NORMAL.....45 DEPARTURE FROM 30-YEAR NORMAL.......................+2 TOTAL DEPARTURE FOR THE MONTH......................+28 [+2.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY..............18 DEPARTURE..........-2 TOTAL HEATING UNITS FOR THE MONTH.............234 DEPARTURE.........-28 TOTAL HEATING UNITS FOR THE SEASON...........4519 DEPARTURE.......-1207 TOTAL HEATING UNITS LAST SEASON TO DATE......5635 DIFFERENCE......-1116 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............25 NNW AT 4:16 P.M. AERO..................24 NNW AT 4:20 P.M. ASOS..................26 NNW AT 4:15 P.M. DAVIS.................25 N AT 4:16 P.M. RMY 28 THE FASTEST MILE FOR YESTERDAY...........18 NNW AT 4:22 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............18 N AT 4:21 P.M. DAVIS MAXIMUM 2-MINUTE AVERAGE...........18 N AT 4:21 P.M. AVERAGE WIND SPEED AND DIRECTION........9.6 NNW ASOS.................9.2 DAVIS................8.9 N [349 deg.] * Last of several occurrences. PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.16 DEPARTURE..........-0.01 ASOS..............0.14 TOTAL PRECIPITATION FOR THE MONTH..........0.34 DEPARTURE..........-1.70 ASOS..............0.31 TOTAL PRECIPITATION FOR THE YEAR...........6.43 DEPARTURE..........-9.61 ASOS..............6.46 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE..........-0.1 TOTAL SNOWFALL FOR THE MONTH................0.0 DEPARTURE..........-1.3 TOTAL SNOWFALL FOR THE SEASON..............24.2 DEPARTURE.........-34.0 PRELIMINARY CLIMATE SUMMARY FOR APRIL 2012 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 when significant 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 50/34/42/+1/0.14/0.0/360/47 20 SSW AERO 20 MPH SSW RMY N/A 4/2 51/35/43/+2/0.04/T/353/46 35 NNW AERO 33 MPH NNW RMY 35 4/3 57/31/44/+2/0.00/0.0/724/94 36 NW AERO 37 MPH NW RMY 40 4/4 62/38/50/+8/T/0.0/688/89 40 NW AERO 39 MPH NW RMY 43 4/5 51/33/42/-1/0.00/0.0/660/85 29 NW AERO 27 MPH NW RMY 30 4/6 51/31/41/-2/0.00/0.0/623/80 26 NNW AERO 26 MPH NNW RMY 28 4/7 54/32/43/0/0.00/0.0/305/39 31 NW AERO 32 MPH NW RMY 32 4/8 51/37/44/0/0.00/0.0/086/11 32 NW AERO 31 MPH NW RMY 33 4/9 57/43/50/+6/T/0.0/323/41 44 W AERO 42 MPH W RMY 44 4/10 61/40/51/+6/0.00/0.0/600/76 32 W AERO 31 MPH W RMY 34 4/11 57/40/49/+4/0.00/0.0/397/50 21 NE AERO 20 MPH NE RMY 22 4/12 54/39/47/+2/0.16/0.0/.../.. 25 NNW AERO 24 MPH NNW RMY 28 4/13 morning low temp: 36F; the normal low is now 37F DAILY RECORDS FOR APRIL 2012 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 13 HIGH 85 IN 1945 LOW 22 IN 1939 PRECIP 2.51 IN. IN 2004 SNOWFALL 6.8 IN. IN 1933 PEAK GUST 59 MPH SSW IN 1995 RECORDS FOR APRIL 14 HIGH 80 IN 1945 LOW 21 IN 1923 PRECIP 2.22 IN. IN 1895 SNOWFALL 8.4 IN. IN 1953 PEAK GUST 71e MPH W IN 1943 TODAY'S REPORT PREPARED BY: Sean Fankhauser