Saturday, December 15, 2018

Saturday Evening Post for December 15th, 2018: A New Wettest Year Ever Set in Washington, D.C. (UPDATED With Precip Totals)

**This entry was posted December 15th, 2018**

**This entry was updated with Dec 15th precipitation information at 3:09 a.m. Dec 16, 2018 - see below.**


It is raining heavily outside as I write this on a day that Washington, D.C., officially -- i.e., as measured at Reagan Washington National Airport (KCDA) -- easily breached its previous record-wettest year ever set in the pre-airport period year of 1889. That amount was 61.33 inches.

Rainfall totals today have been in excess of 2 inches, but I'm going to hold off on posting the actual figures until the calendar day is complete. As of yesterday, KDCA was at 61.07 inches year to date.

Sterling (LWX) NWS radar in standard composite mode looped 9:21 p.m. to 10:04 p.m. Dec 15, 2018

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This rainfall record occurred one month to the day after Baltimore, as measured at Thurgood Marshall Baltimore/Washington Int'l Airport (KBWI), broke its previous record wettest year set in 2003. That amount was 62.66 inches. As of yesterday, it was already at 65.89 inches.

Sterling (LWX) NWS radar in standard base mode reflectivity looped 9:27 p.m. to 10:11 p.m. Dec 15, 2018

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For Washington Dulles Int'l Airport (KIAD), it's wettest year ever was also set in 2003 but I have discovered that there is some uncertainty as to whether that figure is 65.67 inches or 65.69 inches.

Sterling (LWX) county warning area (CWA) advisories as of 10:12 p.m. EST Dec 15, 2018

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As of yesterday, it was at 61.55 inches and you can add at least two inches to that. However, with just 17 days to go, I still don't expect it to reach it before the end of the month/year.

The latter figure appeared here but the former figure is something that Sterling (LWX) is using. I found that out when I called the NWSFO and talked to the meteorologist on duty.

He told me that the discrepancy is arising because of the March 2003 figure -- 2.69 inches in his database but 2.71 inches in that publicly available website (link above).

KIAD's record period only goes back to 1960 -- rather than Jan 1, 1871 as do both D.C. and Baltimore and include pre-airport periods -- but its wettest year ever was well above the previous second wettest year, namely, 59.05 inches in 1972.

Note: The KIAD info was updated above to 65.67 inches from 65.69 inches for 2003 -- but the March 2003 tally remains 2.71 inches rather than 2.69 inches.

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As for the weather tonight, not surprisingly, there are flood warnings in effect around the Metro D.C. and Baltimore areas for the next several hours.

The CWG has had these two entries about the rainfall (links embedded):

Drenched city: 2018 is now Washington's wettest year ever recorded.

PM Update: Flood warning in place for D.C. and surrounding areas, with more heavy rain expected

The second entry is being updated occasionally.

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NWS high-resolution surface weather map for a portion of the eastern and central U.S., 0Z 16 Dec 2018

Note the east-west elongated occluded front extending from a surface low centered over eastern Kentucky to another low right over Norfolk.

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UPDATED 3:09 a.m. Dec 16, 2018

Below are the precipitation totals, departures, and averages (in parentheses) …

Abbreviations and background information:

MTD: Month-to-date:
STD: Season-to-date:
YTD: Year-to-date

"Season" refers to climatological winter, which started Dec 1st. Because it is December, MTD and STD are identical.

The base period for average or normal values is 1981 - 2010.

The full climate record period is Jan 1, 1871 - Dec 16, 2018 for Washington, D.C., and Baltimore, Md., while Dulles records begin intermittently in Jan 1960 and continuous records from Jan 1964. Airport periods for D.C. begins Aug 1945 and for Baltimore in June 1950.

KDCA

Day: 2.55" (Daily record - old record, 1.38" set in 1901 / pre-airport)
MTD/STD: 3.16" +1.59" (1.57")
YTD: 63.62" +25.34" (38.28")

This sets a new yearly precipitation total, surpassing the 61.33" recorded in 1889 by 2.29 inches.

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KBWI

Day: 2.24" (Daily record - old record, 1.35" set in 1948 / pre-airport)
MTD/STD: 2.85" +1.11" (1.74")
YTD: 68.13" +27.88" (40.25")

KBWI surpassed its previous yearly precipitation total of 62.66" recorded in 2003 back on Nov 15, 2018.

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KIAD

Day: 2.49" (Daily record - old record, 1.07" set in 2005)
MTD/STD: 3.06" +1.48" (1.58")
YTD: 64.04" +23.88" (40.16")

KIAD's all-time wettest year is 65.67" recorded in 2003.

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KDMH

Day: 1.54"
MTD/STD: 2.30" +0.56" (1.74")
YTD: 64.96" +25.74" (39.22")

KDMH does not yet have a full 30-year base period. It has a partial record stretching back to April 30, 1998.

End of Rainfall Statistics Update. 

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As a brief update, I'm home this Saturday night after sleeping in late and then going to the gym for a couple of hours. I'm watching the MeTV-aired Super Sci-Fi Saturday Night lineup. I also need to do laundry and make dinner. 

A Lyft electric scooter lies forlornly on its side on a wet sidewalk in the rain, 1400 block W Street NW, Washington, D.C., 4:10 p.m. Dec 15, 2018

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I'm going to limit this entry to just a weather update since I still need to compose my Jukebox Saturday Night entry. I will update this one with the rainfall figures once they are in for the day.

--Regulus

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