MONTHLY WEATHER DATA AND OBS - WESTMONT 1.1W PA JUNE 2010 OBSERVERS NATE AND STEVE MULLINS Special Observations: F=fog, T=thunder, H=hail, S=sleet, G=glaze, DW=damaging winds Observation time for this station is midnight (Eastern US). Temperature, °F Precipitation, In. Liquid Solid 7am 24-hour At Rain Snow/ Snow Date Max Min Obs Equiv Ice Depth Special Obs. 1 78 62 62 .07 2 80 56 67 3 78 61 65 .11 T 4 81 62 62 .55 F,T 5 73 62 64 1.56 F,T 6 74 53 53 .19 7 69 51 51 T 8 74 45 57 9 65 51 64 1.38 F 10 77 57 60 11 83 52 65 12 85 60 70 13 79 68 68 T 14 74 62 62 T 15 66 60 64 .05 F 16 81 64 67 T 17 68 59 59 18 84 52 63 F 19 86 57 65 .37 F,T 20 82 63 66 F 21 88 59 66 22 79 62 71 .35 T 23 84 64 64 .45 F,T,DW 24 80 63 64 .29 F,T 25 81 58 65 F 26 81 57 67 F 27 86 65 75 28 79 65 65 .07 29 74 54 54 30 73 45 52 AVG/SUM 78.1 58.3 63.2 5.44 0.0 - EXT 88 45 75/51 1.56 - - Date 21 30* 27/07 5 - - *=Also occurred on earlier dates Miscellaneous Stats Mean Monthly Temperature: 68.2°F (+1.5°F) Monthly Precipitation Departure: 5.44" vs. 4.86" = (+0.58") Year precipitation to date: 29.68" (+5.60") Season snowfall to date: 163.7" (final total for 2009-2010) Number of days with: Fog 11 Thunder 7 Damaging Winds 1 DETAILED OBSERVATION NOTES 1: Variable clouds, mild & breezy at times with WSW winds shifting to WNW. A few sprinkles, and an isolated brief shower about 6:30pm dropped .07" of rain. Partly cloudy, mostly calm evening. 2: Clearing overnight with a pleasant low of 56. Partly sunny & warm with severe storms headed this way from the west all evening but kept dissipating as they got east of Pittsburgh, where 2+ inches of rain fell. Clouds and low-level winds were from the SW. 3: Mild overnight with a brief thundershower (.11" in 5 min) at 1:15am. Variably cloudy with some threatening clouds at times but no more rain. Became quite humid and muggy with light SW breezes. HEAVY THUNDERSTORMS 4: A brief shower at 12:30am (.05"). Overcast & hazy early, with clouds breaking by 10am. Partly cloudy through the day with warm, humid conditions and increasing clouds during the evening, with a series of brief but heavy showers and thunderstorms between 7:30-midnight .55" fell. Storm at 9:15pm dropped .29" rain in 10 mins with some VERY close lightning. Patchy fog developed late. 5: Occasional brief heavy showers and thunderstorms continued overnight and into the morning with another .57" by 8:30am. Variably to mostly cloudy, humid, another round of heavy rain and thunder from 5-6:45pm, 0.83" of rain fell between 5-6pm. Daily total rainfall 1.56", with a 2-day total thus far of 2.11", with 2.06" in 24 hours since 7:30 pm yesterday. Many roads and basements were flooded throughout town during the early evening storm. Patchy fog early and again late. 6: A warming trend overnight and becoming very windy by daybreak with SW winds gusting 30-40 mph. Continued windy through the morning with a brief downpour at noon, partly to mostly cloudy with diminishing winds shifting to WNW. Temperatures began to fall quickly during the evening. 7: Overcast overnight, yielding to a variably cloudy and pleasantly cool day with light WNW breezes. A few brief light AM showers but not measurable. 8: Clear and cool this morning low 45 F. Partly to mostly sunny with a mild pleasant afternoon high 74 F with light WNW breezes. Clouds increased to overcast by sunset, a cool and calm evening. COOL - MORE RAIN 9: Overcast all day with periods of rain and showers developing around daybreak and continuing off & on all day with several brief periods of heavy rain. Cool with light fog and breezy at times from the WSW. A total of 1.38" of rain fell today, with most showers ending after dusk. 10: Becoming clear to partly cloudy overnight. Partly to mostly sunny, light to occasionally moderate W to NW breezes & pleasant seasonal temps. 11: Somewhat cool this morning low 52 F with partly to mostly sunny skies, calm to light/variable breezes from SW to NW, warm high 83 F. 12: Fair overnight, warm and humid with variably cloudy skies - storm cells split as they approached from the SW - no rain or thunder. Hot high 85 F with heat index of 90 F, occasional SW breezes. 13: A mild & muggy overnight low 68 F with variably to mostly cloudy skies, warm and humid but again no storms materialized. Calm to light W winds. A few sprinkles around dusk but not measurable. 14: Another mostly cloudy, hazy & very humid day. Not as warm as expected as clouds didn't break until evening. Light W winds. Despite heavy overcast at times, again only a few sprinkles fell. 15: Cool AM with early fog, overcast skies & very light winds shifted to SE but variable. Occasional light rain showers from mid-morning to early afternoon. Cloudy cool but humid PM, light SW wind. 16: Cool & cloudy all AM, clouds broke to partly-mostly sunny in the afternoon with warm temperatures humid conditions and moderate SW breezes 20+ mph occasionally. 90% chance of t-storms never happened yet again, only a few evening sprinkles, everything seemed to break up and miss us. 17: Overcast and much cooler than expected with temperatures steady in the low 60s through mid- afternoon, continued partly to mostly cloudy PM with the high struggling to 68, light NW winds. 18: Clear and cooler overnight with early valley fog, sunny with a few scattered clouds and a warm high of 84 F. Gentle breezes were quite variable in direction but were mostly S to W. 19: Clear and somewhat cool early, then mostly sunny and warm. Increasing clouds during the evening with a thundershower from about 8-9pm .37" of rain fell. Some patchy fog developed. 20: AM light fog with denser valley fog. Partly to mostly sunny and warm high 82 F, moderate breezes from mostly W/NW around midday, occasionally shifting briefly to S. Detailed hourly data from my Davis station NA 11:30pm last night - 10:30 tonight due to a PC-station communication error. 21: Fair overnight and all day with very warm temperatures high 88 F though humidity was modest. Winds were very light and from the SW. 22: Fair overnight with increasing clouds early, a brief thunderstorm at 9am with showers continuing for about an hour. Became fair and warmer with humid, muggy conditions afternoon and evening. SEVERE THUNDERSTORM - DAMAGING WINDS 23: Warm and muggy overnight and all day with the low only reaching 68 and a high of 84 combined with high humidities for a heat index of 89. Fair skies with light WSW winds, then increasing clouds by early evening with a rather turbulent thunderstorm at 7pm - a derecho produced intense wind gusts clocked up to 63 mph at the airport, brought down several large trees throughout town and knocked out power at many locations. Occasional thunder and rain continued though 9pm .45" fell. The day's low of 63 was set at midnight, following the cooling storm, with fair skies again. 24: Fog overnight with fair skies. Variably cloudy, mild & humid this morning - a 10-minute downpour with a few rumbles of thunder at 12:15pm followed by rapid clearing & strong W breezes. Partly cloudy & breezy PM with WNW winds and slowly decreasing humidities. 25: Fair and slightly cooler overnight low 58 F. Partly to mostly sunny & warm high 81 F with very light SW winds. 26: Light fog this morning, pleasant temps, warm and sunny with passing high clouds and a very hazy red sunset. Winds light SW. 27: Fair and very warm and humid with passing high clouds again high 86 F with a heat index of 92. Light to occasionally moderate breezes from the SW - very warm at obs (midnight) 75 F H.I. 77 F. 28: Mild overnight with strong SW breezes early. Mostly cloudy with light winds and a brief shower about 2pm. Continued mostly cloudy - a very brief downpour at 10pm. 29: Partly cloudy, cooler & less humid with light NW to W breezes. Skies became mostly clear in the evening with a morning low of 63 F replaced by 54 F at midnight. COOLER 30: Clear & cool overnight low 45 F. Mostly sunny with passing fair-weather Cumulus and light NW breezes, low humidities. A pleasant change from all of the recent heat & humidity. MONTHLY SUMMARY June was slightly wetter and moderately warmer than normal. This was the 4th consecutive month with above normal temperatures, continuing the big turn-around after a very cold winter. Max temperatures were 2.0°F above average, while min temperatures were 1.0°F above. The temperature trend was fairly normal for June, with more consistent warmth during the later part of the month, except for a brief cool spell at the end, with the month's low of 45 F tied on the 30th (previously set on the 8th). While there were no 90-degree days as in May, 14 days were in the 80s. 12 days were in the 70s and 4 days were in the 60s. Except for the 8th and 30th (45 F), lows were consistently in the 50s & 60s. There was a lack of any real extremes, and the typical "barotropic" summer-like pattern prevented any major temperature swings like we saw in the spring months. Warm and humid was the general rule. Most of the month's precipitation, over 70% of it, fell in the first 9 days. The heaviest event was on the 4th-5th, when multiple rounds of thunderstorms with heavy downpours dropped 2.06" of rain in a 24-hour period and caused some road and basement flooding throughout town. A strong cold front on the 6th brought in a brief cool spell, which lasted until the 11th. The other heavy rain event was on the 9th, which had the month's coldest max temperature of 65. 1.38" of rain fell. The weather pattern then dried out considerably during the balance of the month. Only 1.58" of rain fell in the final three weeks of June. Most of this fell from the 19th-24th, when a series of fast-moving MCS's moving east from Ohio produced brief but intense thunderstorms. The area endured its third severe weather episode in as many months on the evening of the 23rd, when a squall line whipped through about 7pm, bringing down numerous trees and power lines, and causing over 10,000 power outages. The winds were clocked at 63 mph at the airport. This brief but intense storm and the heavy rains early in the month were June's main weather highlights.