October 2013 had a whole lot of everything.
We had dry spells, a very wet episode, impressive early October heat, and a faster return to the 30s for lows compared to last year.
The temperature spanned 55 degrees at Reagan National Airport from the early month 90F peak to last week’s 35F bottoming out.
All-in-all, the variability still tilted warm due to the very strong start placing 2013 as the 2nd warmest of the 2000s and the 14th warmest of all-time at 2.9F warmer than the 30-year (1981-2010) benchmark normal.
Precipitation was the third highest of the 2000s and 12th all-time thanks to the very wet mid-month, placing it 2.85″ above normal.
Temperatures in detail
The average high temperature of 62.4F was enough to be the second warmest of the 2000s, but still well below 2007′s powerhouse 67.1F very warm outcome.
High temperatures ranged from 54F to 90F, but were mostly in the 60s and 70s. Low temperatures ranged from 35F to 69F, but were mostly in the 50s and 60s, but 30s and 40s in the final third of the month. Of the three airports, we only had temperature records at Dulles due to the early month warm period:
* Dulles had record highs on Oct 4th (90F), Oct 5th (90F), and Oct 6th (89F) matching or beating highs from 2007, 1967, and 1995 respectively.
The graphic below shows the day-by-day details for the month for Washington Reagan National Airport. Our biggest warmth was at the start of the month with our bigger cool period being just last week- quite the contrasting:
Looking through the 2000s does not offer any big trends, but the warmest and coolest years were back-to-back (2006 and 2007):
After a very dry September, October really delivered, especially at mid-month, which was the main reason for October 2013′s third wettest ranking in the current new century.
Daily records were set on October 11th at all area major airports:
* National’s 2.76″ beat 1905′s 1.10″
* Dulles’ 3.38″ bested 2002′s 0.91″
* BWI’s 3.66″ outperformed 2002′s 1.13″
The chart below shows the ranking through the 2000s as well as the general trends:
The daily view at National is below and you can see the very busy mid-month rain event with a few smaller events elsewhere. The airport reported a non-measurable trace on six additional days.
The wet October has now put the year at 2.27″ above normal at National.
The weather pattern
The jet stream pattern was a mixed story in October with the first two-thirds of the month seeing warm upper level ridging patterns affecting our area more and then the final third showing more early season cold pushes dropping down via a cool Eastern upper level trough. The impetus for the colder weather was a far more powerful upper level ridge in Western Canada and the Northeast Pacific that may have been driven by a serious of strong re-curving typhoons from the far western Pacific. That Western Canadian ridging feature see-sawed a deeper cool to cold trough into the East. You can see the patterns from the upper level height anomalies here:
The start of our new month is promising to be quite the roller coaster with episodes of warming and cooling expected over at least the next two weeks. This variable pattern makes it difficult to pinpoint the expected temperature anomaly, but we may eke out a slight warm anomaly. Precipitation may manage to be near or slightly higher than normal given the active pattern.
The National Weather Service only has the D.C. area in the EC category meaning equal chances for above, below, or normal temperatures and precipitation. You can see their depiction here.
For further information
The National Weather Service publishes nice monthly assessments usually within a week of the close of each month (should be available shortly):
You can click on your closest airport location here: