MONTHLY WEATHER DATA AND OBS - LAVALE MD DECEMBER 2008 OBSERVER SCOTT LOHR DATA COMPILED AND PUBLISHED BY NATE MULLINS Special Observations: F=fog, T=thunder, H=hail, S=sleet, G=glaze, DW=damaging winds Observation time for this station is midnight. Temperature, °F Precipitation, In. Liquid Solid 7am DAY 24-hour Rain Snow/ Snow Special WEATHER Date Max Min Equiv Ice Depth Obs. SUMMARY 1 40 31 F Early fog, then mostly sunny 2 35 28 Mostly cloudy 3 47 23 Mostly sunny 4 45 35 Mostly cloudy 5 35 26 T T Cloudy, few flurries 6 26 15 .01 0.2 Cloudy, PM light snow 7 25 15 .02 0.3 T Windy, cold, variable clouds, snow showers 8 29 14 T Cloudy, some clearing late 9 47 25 T Mostly cloudy 10 45 35 .54 F Cloudy, rainy 11 41 35 1.39 F Rain all day, heavy at times 12 38 31 .17 T T F Rain ended. Became partly sunny 13 35 22 Partly cloudy 14 45 25 Partly cloudy to mostly sunny 15 60 35 Partly cloudy, mild, becoming mostly cloudy PM 16 37 31 .57 2.0 T F,S,G Snow, changing to sleet & freezing rain 17 39 32 .37 T 2 F,G Precip ended overnight, cloudy, clearing late 18 38 32 2 Mostly cloudy 19 43 34 1.23 1 F Heavy rain, tapering off by late afternoon 20 34 31 .03 T F,S Mostly cloudy, brief period of late PM sleet 21 36 13 Partly cloudy, windy, falling temps 22 18 6 Partly cloudy, very cold, breezy, blustery 23 30 11 Mostly cloudy 24 46 31 .96 T T F,G Steady rain, some freezing rain, cleared/windy late 25 40 32 Cloudy, windy 26 39 23 .34 Partly cloudy, then increasing clouds with rain 27 49 32 F AM fog, partly cloudy, fog again PM 28 54 30 Mild early, mostly sunny, windy, falling temps 29 46 30 Mostly sunny, very windy 30 47 32 Mostly sunny, breezy 31 32 20 .04 1.0 1 Very windy, blustery, snow squalls, falling temps AVG/SUM 39.4 26.3 5.67 3.5 0.2 <--Mean EXT 60 6 1.39 2.0 2 Date 15 22 11 16 18* *=Also occurred on earlier dates Miscellaneous Stats Mean Monthly Temperature: 32.8 F Year precipitation to date: 45.72" (final total for 2008) Season snowfall to date: 6.4" Number of days with: Fog 10 Sleet 2 Glaze 3 NOTES AND/OR SIGNIFICANT EVENTS 6-7: Light snow, snow showers. Heavier accumulations in the mountains with little to no accumulation in the valleys 10: Steady light to moderate rain. December 10th is statistically the 3rd wettest day of the year in my 17 years of record keeping with a mean of 0.376 inches, only behind July 30 (0.446") and September 6 (0.408"). Interesting - maybe because it's my birthday? :) 11: Steady rain heavy at times especially during the evening. Daily record of 1.39 inches shatters the old Dec. 11 record of 0.64" set in 1992. Storm total precipitation from Dec. 10-12 = 2.10". Some ice/glaze at higher elevations. 15: Mild high 60 F. This warmth was short-lived, as the high only reached 37 the following day. 16-17: Winter storm brings moderate snow, sleet and freezing rain. 2" of snow/ice accumulation and nearly 1" of melted precip. 19: Heavy rains during the morning and through mid-afternoon. Another daily record 22: Very cold high only 18 F and low 6 F with wind chills around -20 F. One of the coldest days in nearly 2 years. 24: Rain, some of it freezing, with glaze, especially at higher elevations. Ironically, the higher elevations also had higher max temperatures today, due to a thermal inversion during the PM hours that was quickly eroded by strong winds accompanying a cold front with rapid clearing by late evening this Christmas Eve. Another daily record precip was set. Heaviest rain fell to our North, with 2.31" recorded at my Westmont 1.1W PA station. 25-26: Windy snow-less Christmas day with seasonal temperatures. Clouds moved in quickly late on the 26th with a period of moderate evening rain. 28: Strong cold front moved through, dropping temperatures from 54 to 30. Some light precipitation at higher elevations with damaging winds at those locations 29: Very windy, especially after sunset and this was also observed at my Westmont PA station. Wind seemed to come up out of nowhere and was a surprise with an absence of any notable fronts or other weather features. 30: Breezy again 31: Very windy, NW winds sustained ~20 mph and gusting 40+ mph. Snow squalls through the day with ~1" accumulation. Temperatures dropped steadily. MONTHLY SUMMARY December was a wild and wacky month, particularly in the temperature department, but with some interesting precipitation observations as well, and was also a very windy month, with numerous days of gusts over 30 mph. Predictably, as this has been a very common phenomena lately, the mean min temperature was above the 61-year average (26.3/24.6 F). However, like in November, the negative anomaly in the max temperature department (39.4/42.2 F) slightly outweighed the above normal mins, leading to an overall temperature slightly below average (32.8/33.4 F). It was difficult to pinpoint any particular temperature trend, due to the seemingly endless parade of fronts that led to a yo-yo temperature pattern. Also, I don't think I've ever seen so many thermal inversions as I did this month. On many days, temperatures would be at or below freezing here while in the 50s at nearby higher elevations. Parts of Garrett Co. (e.g. Eagle Rock at 3,000 ft. elevation) were nearing 70 shortly after Christmas, while we were stuck in the 40s, with just one day in the 50s on the 28th, shortly before another cold front plowed through with falling temperatures and strong winds, another common theme this month. Given the hefty precipitation total, 5.67 inches, which is the highest December total in my 17 years of observing, and ties 1972 for the 3rd wettest December in 61 years of records (since 1948), and the strong thermal inversions that seemed to accompany nearly every signficant system, predictably, there were several ice storms with little snowfall through the month. Significant ice storms hit either here or nearby mountain locations on the 11th-12th, 16th-17th, and Christmas Eve. The worst winter storm struck on the 16th-17th, with a mess of snow, sleet and freezing rain that snarled travel in the area. Only 3.5" of total snow/ice fell all month, about half the normal of 7.1 inches. On the other hand, it was a wet and at times icy month, again 3rd wettest since 1948, wettest since 1992 and six days (11,12,16,19,24,26) setting daily precipitation records (since 1992). The active, wet weather pattern in December boosted 2008 to the 10th wettest out of 61 years of records with 45.72" of yearly precip. 2008 was the first year since 2003 with below normal temperatures, although slightly, with a mean annual temperature of 51.8 F, which is exactly average (51.8 F). Additional notes/records 6: Daily record low max 26 F 11: Daily record 1.39" of precipitation. 16: Daily record 2.0" snowfall. 19: Daily record 1.23" of precipitation. December 2008 tied Dec. 1972 for 3rd wettest December on record with 5.67". The year 2008 ranked 4th coolest for mean annual max temperature (60.0 F). However, 2008 also ranked 5th warmest for mean annual min temperature (43.5 F). In other words, 2008 had a record low diurnal variation mean of 16.5 F.