November obs and banter

[RodneyS]

actually, dec 2010 all three were by a good bit.. close to -5

Right, then January 2011 came in a couple of degrees below normal at all three Baltimore/DC airports, and also below historical 1871-2010 January averages. From that month until November 2012, every month was above its historical averages, except for October 2011, which was about even with those averages. November 2012 at DCA comes in at 0.9 degrees below its historical November average.

[wxdude64]

IAD is at -3.9 heading into today...that seems impressive to me in light of recent years out this way with temp trends. Im sure it means nothing but still an impressive departure all things considered.

Yeah, most sites in western VA and WV running (-3.5) to (-4.5) for the month. Been a while since that much of a negative difference from average.

[Kevin Shaw]

NOVEMBER 2012 - GAITHERSBURG 2 WNW MARYLAND - STATION HIGHLIGHTS

by observer in charge, Kevin Shaw

November 2012 was my first month since January 2011 that had below normal max, min, and mean average temperatures. I had my 6th coolest average maximum temperature in my 34 years of records. My minimum temperature of 33.3° was the coolest average November min since the 32.9° I had back in November 2002. Likewise it was the coolest mean average temp (42.6°) since November 2002 when I had 42.3°. The only temp records set during the month were the low max temp records of 45 on the 6th and 43 on the 7th. At the end of November I completed 34 full years of precipitation records at my station. This November was only the second ever that I would characterize as being dry and cool. The 0.97" of total rainfall for the month was my second lowest November total ever, only surpassed by the 0.38" that fell back in November 1981. Needless to say no precipitation records were set during the month. A rather minor event on the 13th tied an old record (1984) for the date for most snow/sleet with a Trace. Sleet fell for a short time that morning that I only noticed because I was driving through it when it occurred. Four days of measurable precipitation falling during the month tied 1981 for the least amount of days with measurable precipitation occurring.

The total precipitation of 0.97" that fell in November was 2.85" below normal, and helped turn an above normal year through October to a below normal year through the end of November. There were only 4 days of measurable precipitation, well below normal levels, and tied 1981 with the fewest days ever in November.

Temperature-wise the statistics show a fairly large negative departure from normal on the max side (-3.3°) and a 1.4°below normal departure on the min temperature side. The combination of these figures resulted in a 2.4° below normal average mean temperature. Temperature extremes for the month were once again muted. The maximum temp for the month didn't even reach 70 (68° on the 12th) and the min didn't get lower than the mid 20s (26° on the 26th, 29th and 30th). The 13 days with 32 or lower min temps was the most since 18 days were recorded back in 2002.

The highest pressure reading of 30.64" on the 18^th occurred during the mid month dry spell and was the highest value since March. The lowest pressure reading was 29.67" on the 1st that was at the tail end of the Hurricane Sandy-influenced very low pressure values at the end of October. The 23 MPH PWG from the NW on the 8th was considerably less than the winds from Sandy just a week or so earlier. The distribution of 13 clear, 10 partly cloudy and 7 cloudy days fit in fairly well with the dry patterns of the month.

There were no thunderstorm days in November, and only 2 days with fog, considerably below normal. There was the one day with sleet on the 13th (T). There were no cooling degree days in November. However, there were 671 heating degree days, definitely an above normal value for November. Speaking of numbers, my maximum temperature frequencies included 4 days from 60-69, 13 days from 50-59, and 13 days from 40-49. There were only 2 days with minimum temperatures above 40, 22 days between 30-39, and 6 days between 20-29.

The diurnal range average was below normal (18.6° vs a normal of 20.5°) with a max daily range of 30.7° on the 10th as we were on the rebound from a cool spell into the warmest spell of the month. The 6.4° lowest monthly range on the 27th occurred on a light, cold rainy day when my lowest max temp of the month occurred (40°). There were only 4 days with ranges under 10° during the month, with conversely 7 days of ranges of 25° or greater, somewhat of a by-product of a dry fall month.

It was an amazing turnaround in November after a record setting wet October which of course was mostly due to the passage of Hurricane Sandy.