Friday, July 10, 2015

The Baltimore/Washington High Summer 2015 Rain Chronicles; Los Angeles Multi-Year Drought Update; Start of the Southwest Monsoon Season

**This entry was posted on July 10, 2015.**

A picture of a microburst over part of Washington, D.C., as seen from the top of the Washington Monument looking to the east toward the U.S. Capitol on July 8, 2015.

The image was posted in this CWG entry from a Twitter posting by "Catherinerrr" (or "Catherinerrrr") and posted here. The CWG entry timestamp says 5:13PM but the original Twitter picture has 2:13PM. As I recall (since I work just off the National Mall) is that the rainfall occurred around 5PM.

The slight hill just barely visible through the curtain of heavy rain is "Mount Hamilton" at the National Arboretum. Oh, yes, I haven't been atop the Washington Monument (in its observation deck, that is, since at least 1994).

A deluge floods a roadway in Oakton in Fairfax Co., Va., in a photo taken by Stephen Repetski and posted in the same CWG entry linked above.

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The past two days has witnessed additional moderate-to-heavy rainfall in the immediate Metro D.C. area, adding to the large surpluses across the region for climatological summer (reckoned since June 1st). Most of it fell on Wednesday in tropical-like downpours in the late afternoon into early evening hours.

NWS Doppler radar estimated precipitation for July 8, 2015 across the Baltimore/Washington region with legend on the right.

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July 8th (Wednesday) witnessed the most rainfall in a relatively narrow band that included the official weather (climate) station at Reagan Washington National Airport (KDCA), although July 9th (Thursday) saw a bit of extra rain. The Wednesday rainfall actually bisected the District with areas north of the National Mall getting much less. (The White House rain gauge reportedly picked up just 0.36" on Wednesday.)

Somber looking sky (looking east-southeast) with receding storm clouds at dusk after the main rainfall as seen from the corner of New Hampshire Ave and 15th Street NW, Washington, D.C., 7:31PM July 8, 2015.

Actually, it looked threatening in the southwest, too, but nothing came of it. I was walking to the YMCA where I had a decent workout including jog (NOT at much of an incline!), weightlifting, and swim.

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The Baltimore area mostly missed out on the Wednesday rainfall including at the Baltimore/Washington Thurgood Marshall Int'l Airport station (KBWI). By contrast, the Washington Dulles Int'l Airport station (KIAD), which has missed several of the heavy rainfall totals since June 1st, got deluged on Wednesday. The Maryland Science Center station (KDMH) at the Inner Harbor in Baltimore City missed the Wednesday rainfall and had a bit on Thursday.

The Enid Haupt Garden as seen on Thursday evening, 7:13PM July 9, 2015.

It wasn't a gym night and I walked to the Smithsonian Metro rather than going to Elephant L'Enfant Plaza.

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The amounts are listed below. However, before I post the totals, let me just say that the Capital Weather Gang crew has been moaning and bellyaching about all the rainfall.

Vibrant green plants including palms and whatnot in the Enid Haupt Garden, Smithsonian, Washington, D.C., 7:16PM July 9, 2015.

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Now I get the fact that the Palka-Cabra Creature wants it hot and rainless (or whatever it is that She-Dragon wants) but the CWG crew's moaning is annoying. We are nearing "high summer" when it is usually overheated and disgustingly humid but with days or even over a week at a time with no real rainfall. This year is warm and humid but at least it's wet and verdant green the natural world.

There she is ... The Palka-Cabra ...

ROAR!!

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Actually, the second entry (by Jason Samenow) has an interesting tidbit:

Since June 1, Reagan National has logged a remarkable 15.28 inches of rain -- which is almost 50 percent more than it receives in an entire summer on average (10.44 inches). This has been the second wettest June 1-July 8 period on record (since 1871), only behind the 16.55 inches of 2006.

For some perspective, consider Los Angeles International Airport has received just 14.51 inches of rain since the start of 2013, or over the last 30 months. Reagan National has that beat in the last 38 days. If only we could ship some over there…

The downtown Los Angeles USC campus NWS station (KCQT) climate graph for all of 2014 showing temperature and precipitation.

There is also a snowfall portion (below the precipitation portion) that I did not include since, obviously, it doesn't snow in L.A.

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Of note, there was a public information statement issued by the Los Angeles / Oxnard NWS Forecast Office (LOX, not to be confused with LAX Airport) on the tremendous Southern California drought of the past several years. I can't link to it because these statements -- like NWS forecast products -- slowly recede as new ones are issued.

The KCQT climate graph for 2015 through July 8, 2015 showing temperature and precipitation.

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The bottom line of that Public Information Statement is this (as measured at the downtown L.A. NWS station at USC, denoted KCQT; the pictures are just extra to break up the text):

...DRIEST FOUR CONSECUTIVE RAIN SEASONS EVER RECORDED IN DOWNTOWN LOS ANGELES...

RAINFALL FOR THE 2014-2015 RAIN SEASON IN DOWNTOWN LOS ANGELES TOTALED 8.52 INCHES...OR 57 PERCENT OF THE NORMAL RAINFALL OF 14.93 INCHES. THE RAINFALL TOTAL FOR THE PAST FOUR CONSECUTIVE RAIN SEASONS BEGINNING WITH THE 2011-2012 SEASON WAS 29.14 INCHES. THAT WAS THE LOWEST RAINFALL TOTAL FOR 4 CONSECUTIVE SEASONS SINCE RECORDS BEGAN IN 1877. THE PREVIOUS RECORD WAS 34.02 INCHES FOR THE 4 SEASONS FROM 1947-1951.


RAINFALL FOR THE PAST 4 CONSECUTIVE SEASONS COMBINED IN DOWNTOWN LOS ANGELES WAS MORE THAN 30 INCHES...OR TWO AND A HALF FEET...BELOW THE NORMAL FOR THAT PERIOD...WHICH WOULD BE 59.72 INCHES. RAINFALL HAS AVERAGED JUST 49 PERCENT OF NORMAL DURING THIS EXTENDED TIME.

THIS IS THE FIRST TIME SINCE RECORDS BEGAN IN DOWNTOWN LOS ANGELES IN 1877 IN WHICH LESS THAN 10 INCHES OF RAIN HAS BEEN RECORDED IN
FOUR CONSECUTIVE RAIN SEASONS.

That damn totally cemented, usually practically dry Los Angeles River running through L.A. It's supposed to be "restored" by the U.S. Army Corps of Engineers in some fashion at some point.

How many frickin' movie drag races and TV show car chases took place in that "river bed" over the decades??

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RAINFALL HAS TOTALLED LESS THAN 10 INCHES IN THREE CONSECUTIVE SEASONS JUST 5 TIMES...JULY 1ST 1897 TO JUNE 30TH 1900... JULY 1ST 1922 TO JUNE 30TH 1925...JULY 1ST 1958 THROUGH JUNE 30TH 1961...JULY 1ST 2011 TO JUNE 30TH 2014...AND JULY 1ST 2012 TO JUNE 30TH 2015.

THIS WAS ALSO THE 8TH SEASON SINCE THE 2001-2002 SEASON IN WHICH LESS THAN 10 INCHES OF RAIN WAS RECORED.

There have been thunderstorms in the High Sierras and east into the high deserts of western and southern Nevada the past few days with flash flood watches and a few warnings in place. This is part of the summer "North American Monsoon" season in the Western U.S., also called the Southwest Monsoon, although this year so far, it is extended somewhat farther north than usual into the High Sierras and up to Oregon. (Any and all rain should be so welcome in anywhere in California.)

The Las Vegas NWS forecast office (VEF) county warning area (CWA) advisories map, 5:27AM PDT July 7, 2015.

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Indeed, check out this rather amazing picture:

A fierce looking wet microburst over Las Vegas as seen from a passenger jet on final approach into (or taking off from?) McCarran International Airport on July 7, 2015.

This picture was taken by a person named Pat Hurst and posted in this CWG entry. The storm dropped 0.83" of rain in just 15 minutes in one spot (causing instant muddy flash flooding). No passenger jet should be anywhere that kind of microburst. The jet will lose and lose badly in an instant.

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Of note, I discovered that when there is a red flag warning and a flash flood watch in place in a given region, the latter actually takes precedence over the former, as happened in and around Medford, Oregon on July 8th:

The Medford (Oregon) NWS forecast office CWA weather advisories as of 8:35AM PDT July 8, 2015.

To be clear, Medford and its immediate environs of Jackson County were under both weather advisories at the time. It seems odd to me that the watch should take precedence over the warning, especially that kind of warning.

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(Oh, yes, the NWS has begun using its new forecast icons and in the point grid forecasts, a new system for showing advisories in effect -- including multiple ones. I'll show those some other time.)

Despite the scattered High Sierra rainfall -- oh, and my friend Natan and his girlfriend Julia and a companion are presently hiking 200+ miles of the John Muir Trail / Pacific Crest Trail in the backcountry* -- there was nothing in Southern California.

*JMT and the far longer PCT run coterminous for much of the JMT's run.

Speaking of "SoCal" rainfall, my (admittedly weird) dream in life is know that a category 3 hurricane is about to make a direct hit on Los Angeles in late summer and fly there and get to experience it. Yes, hurricane (i.e., 74MPH+ tropical cyclone) strikes on Southern California can happen, but at that intensity (as opposed to weak and/or remnant ones), it's probably a once-in-a-500 year to once-in-a-1000 year event in the current climate regime, and even if it were to happen, I just wouldn't have enough lead time to prepare.

The Los Angeles skyline on a particularly clear day with the snow-capped San Gabriel Mountains (including, I believe, Mount San Antonio itself, a.k.a., "Mount Baldy") in the backdrop, Dec. 10, 2007. This is a picture from Wikipedia.

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In any event, if I had to proffer a meteorological guess, I think California in general will have a wet winter courtesy the strong warm ENSO ("El Nino") event developing / already underway (provided the PDO and/or AO don't interfere with it).

Anyway, here are the precipitation totals for the Baltimore/Washington region through July 9th, 2015:

KDCA
July 8th: 1.12"
July 9th: 0.03"
Month-to-date: 3.37" +2.25" (1.12")
Since June 1st: 15.31" +10.41" (4.90")
Year-to-date: 30.09" +9.23" (20.86")

The KDCA climate graph for 2015 through July 8, 2015 showing temperature, precipitation, and snowfall.

Note: This climate graph is through July 8, 2015 so it differs slightly on precipitation.

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KBWI
July 8th: T
July 9th: 0.05"
Month-to-date: 1.79" +0.69" (1.10")
Since June 1st: 14.88" +10.32" (4.56")
Year-to-date: 32.08" +10.49" (21.59")

The KBWI climate graph for 2015 through July 8, 2015 showing temperature, precipitation, and snowfall.

Note: This climate graph is through July 8, 2015 so it differs slightly on precipitation.

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KIAD
July 8th: 1.60"
July 9th: T
Month-to-date: 3.04" +1.96" (1.08")
Since June 1st: 10.48" +5.42" (5.06")
Year-to-date: 24.34" +2.46" (21.88")

The KIAD climate graph for 2015 through July 8, 2015 showing temperature, precipitation, and snowfall.

Note: This climate graph is through July 8, 2015 so it differs slightly on precipitation.

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KDMH
July 8th: 0.13"
July 9th: 0.00"
Month-to-date: 1.14" -0.13" (1.27")
Since June 1st: 8.78" +4.24" (4.54")
Year-to-date: 25.12" +4.49" (20.63")

Note: KDMH does not yet have a full 30-year climate "normal" period (and hence no climate graph).

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OK, that's all for now. It's late and I'm going to refrain from any personal update in this entry.

--Regulus

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