BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, MAY 21, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME MONDAY HIGH TEMPERATURE TOPS 80F FOR 2ND TIME THIS SEASON; WARM AND MUGGY START TODAY QUICKLY REVERSES WITH AFTERNOON SEA BREEZE On Monday, the high temperature warmed to 81F, the warmest temperature recorded so far this season. This was only the second 80F or higher temperature recorded so far this season. This morning began quite warm and muggy. A rare, partial undercast was noted during the 8 AM EDT observation. Quite a sight. With a southerly wind developing, temperatures quickly warmed into the 70s this morning, reaching a high of 81F right around noon EDT. The dew point temperature also briefly rose into the upper 60s before a sea breeze kicked in shortly there after. Shortly after noon EDT a sea breeze quickly developed, with winds backing around to a NE direction. The temperature and dew point quickly began dropping as a result. By 3 PM EDT, the temperature had fallen to 60F, with a dew point in the 50s. A layer of low stratus and fog slowly also quickly enveloped the summit between 2:30 and 3 PM EDT, reducing visibility to 1/2 mile to 2 miles. Today's observations: 7 A.M. Weather: Sky partially obscured by fog, scattered altocumulus, scattered thin cirrus, partial undercast all quadrants, stratus occasionally drifting over summit, few altocumulus/altocumulus lenticularis distant N, few cirrus distant S-W, hazy Temperature: 64F; Dew Point: 61F; Wind: ESE at 5 kts, Wind: Light Sea-level pressure: 29.95 ins. Hg, rising then falling Visibility: 2 miles, variable 1/2 to 5 miles, hazy 24-hr precip: Trace 6-hr min. temp: 61F BHO SA 1155 –X 60 SCT 250 –SCT 2VF 143/64/61/1105/995/ F2 PARTIAL UNDERCAST ALQDS STRA OCNLY DRFTNG OVR SMT FEW AC/ACSL DSNT N FEW CI DSNT S-W HAZY VSBY 1/2V5 WND LGT/ 8/641 58003 MANUAL 7000/ 10065 20061 10 A.M. Weather: Scattered cumulus, scattered altocumulus, cumulus/cumulus fractus all quadrants, few altocumulus/altocumulus lenticularis N-NE, low stratus/fog over ocean NE-ENE, hazy Temperature: 76F; Dew Point: 67F; Wind: S at 6 kts, Wind: Direction variable SE-SW Sea-level pressure: 29.93 ins., falling Visibility: 15 miles, N-E 10 miles, WNW 20 miles, hazy BHO SA 1455 15 SCT 60 SCT 15 137/76/67/1806/993/ CU/CUFRA ALQDS FEW AC/ACSL N-NE LW STRA/FG OVR OCN NE-ENE HAZY VSBY N-E 10 WNW 20 WND 13V22/ 8/140 58006 1 P.M. Weather: Scattered stratus, scattered cumulus, scattered altocumulus, scattered thin cirrus, low stratus/fog layer N-E, few cumulus and moderate cumulus SE-SW-NW, cumulus congestus S-SW, few altocumulus lenticularis ESE-SSE, few cirrus WSW and NW, hazy Temperature: 71F; Dew Point: 62F; Wind: ENE at 9 kts. Sea-level pressure: 29.90 ins. Hg, falling Visibility: 15 miles, NNE-E 8 miles, WNW 20 miles, hazy 6-hour max temp: 81F BHO SA 1755 2 SCT 25 SCT 60 SCT 250 –SCT 15 124/71/62/0609/990/ LW STRA/FG LYR N-E FEW CU AND MDT CU SE-SW-NW CU CONGESTUS S-SW FEW ACSL ESE-SSE FEW CI WSW AND NW VSBY NNE-E 8 WNW 20 HAZY/ 8/841 55013 10081 20064 WEATHER SUMMARY FOR MONDAY, MAY 20, 2013 TEMPERATURE (DEGREES F) MAX.....81 NORMAL.....68 MIN.....54 NORMAL.....49 MEAN....68 NORMAL.....58 DEPARTURE FROM 30-YEAR NORMAL...................+10 TOTAL DEPARTURE FOR THE MONTH...................+45 [+2.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............0 DEPARTURE..........-8 TOTAL HEATING UNITS FOR THE MONTH...........150 DEPARTURE.........-50 TOTAL HEATING UNITS FOR THE SEASON.........5672 DEPARTURE........-563 TOTAL HEATING UNITS LAST SEASON TO DATE....4875 DIFFERENCE.......+797 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............21 S AT 1:23 A.M. AERO....................21 S AT 1:23 A.M. ASOS....................23 S AT 1:23 A.M. DAVIS...................21 WSW AT 10-11 A.M. RMY: N/A FASTEST MILE FOR YESTERDAY.................16 SSE AT 1:07 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE..............16 W AT 10:53 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............16 W AT 10:53 A.M. AVERAGE WIND SPEED AND DIRECTION..........9.7 W ASOS...................9.6 DAVIS..................8.9 SW [224 deg] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...Trace DEPARTURE...........-0.13 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.08 DEPARTURE...........-1.40 ASOS..............1.02 TOTAL PRECIPITATION FOR THE YEAR..........17.46 DEPARTURE...........-3.57 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.............0.0 TOTAL SNOWFALL FOR THE MONTH...............0.0 DEPARTURE.............0.0 TOTAL SNOWFALL FOR THE SEASON.............99.0 DEPARTURE...........+36.3 PRELIMINARY CLIMATE SUMMARY FOR MAY 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 5/1 67/45/56/+3/0.00/845/100 18 E AERO 16 MPH E RMY 17 5/2 75/43/59/+6/T/669/79 29 NE AERO 26 MPH NE RMY 29 5/3 54/42/48/-5/0.00/706/83 24 NE AERO 25 MPH NE RMY 28 5/4 55/40/48/-6/0.00/843/99 21 NE AERO 23 MPH NE RMY 23 5/5 58/37/48/-6/0.00/752/88 17 ENE AERO 17 MPH ENE RMY 20 5/6 66/40/53/-1/0.00/600/70 17 S AERO 18 MPH S RMY 20 5/7 77/50/64/+9/0.00/807/94 21 S AERO 23 MPH S RMY 25 5/8 71/55/63/+8/0.42/112/13 31 SSE AERO 35 MPH SSE RMY 35 TSTM 5/9 66/56/61/+6/0.41/078/09 16 NE AERO 16 MPH NE RMY 18 TSTM 5/10 79/54/67/+12/T/333/63 18 S AERO 21 MPH S RMY N/A 5/11 70/56/63/+7/0.06/026/03 43 SSW AERO 44 MPH SSW RMY 46 5/12 71/47/59/+3/0.05/339/39 30 W AERO 32 MPH W RMY 32 5/13 60/41/51/-5/0.00/821/94 25 WSW AERO 28 MPH WSW RMY 30 5/14 58/38/48/-9/T/385/44 22 W AERO 24 MPH W RMY 25 5/15 65/41/53/-4/0.02/456/52 35 S AERO 38 MPH S RMY 40 5/16 80/51/66/+9/0.00/844/96 40 W AERO 45 MPH W RMY 42 5/17 69/50/60/+3/0.00/872/99 24 NW AERO 28 MPH NW RMY 27 5/18 73/47/60/+2/0.00/689/78 21 SE AERO 24 MPH SE RMY 24 5/19 71/50/61/+3/0.11/407/46 21 S AERO 23 MPH S RMY 24 5/20 81/54/68/+10/0.01/.../.. 21 S AERO 21 MPH S RMY N/A 5/21 morning low temp: 61F; the normal low is now 49F DAILY RECORDS FOR MAY 2013 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 21 HIGH 92F IN 1921 LOW 35F IN 1907 PRECIP 1.61 INS IN 1954 PEAK GUST 74 MPH WSW IN 2006 RECORDS FOR MAY 22 HIGH 93F IN 1911 LOW 35F IN 1907 PRECIP 3.75 INCHES IN 1920 PEAK GUST 49e MPH SSW IN 1947 TODAY'S REPORT PREPARED BY: Sean Fankhauser