It Hasn't Cooled Since 1989;Washington December Daily Low Temperature Records

Images (click to enlarge): December daily record low temperatures for Washington, DC, by year of occurrence; Number of December daily record lows per decade; CapitalClimate charts from National Weather Service data

If you can remember the last time Washington, DC set a daily record low temperature in December, you've been hanging around too long in Babble-On on the Potomac. It was the first year of the G.H.W. Bush administration when a record low of 7° was set on December 23, 1989. The high of 22° that day was also a record low maximum for the date. Since then, there have been no new December record daily lows in the decades of the 1990s, 2000s, or so far in the 2010s. The only other decade with no December cold records was the 1950s.

Here are some other statistics of Washington December low temperature records:
- Half (15) of the daily records were set over 100 years ago, from 1872 through 1904, and 2 more were set 99 years ago.
- The 1880s had the most records of any decade with 7, followed by the 1910s with 5. Interestingly, all of the 1880s records occurred in even-numbered years.
- Except for the 1980s (4 records), no decade since the 1910s has had more than 2 records.
- The all-time coldest December temperature was -13° on December 31, 1880. This was just 2° warmer than the all-time Washington low of -15° on February 11, 1899. It was also a record -7° on December 30, 1880. These are the only December dates with lows below 0°.

Rain's Early Fall Smashes Pacific Northwest Precipitation Records

September 30 Update: September monthly precipitation records have also been set in Oregon at Eugene, Hillsboro, McMinnville (second highest), Portland (downtown and airport), and Salem, as well as at Vancouver, Washington. Details have been added below.

Original post:
Driven by persistent abnormally low pressure in the northeastern Pacific, an early onset of the rainy season is smashing precipitation records for September in the Pacific Northwest. Through this morning, Astoria, Oregon had broken century-plus records for all-time wettest September (by over 1"), wettest September day (by almost 1"), and wettest 2-day and 3-day totals for September. These records were further extended by the 2.00" which had fallen through 4 pm this afternoon, tying the daily record for Sept. 29 from 1951 and bringing the monthly total to date to 10.10", which is just 0.10" less than 500% of normal.

The rainfall map above shows that large parts of coastal Oregon have seen precipitation for the month of September to date (through the 28th) which is over 400% of average, with some areas over 600%.

The map to the right (click to enlarge) shows the pressure pattern Saturday evening over North America near the middle of the atmosphere, expressed as the standard deviation of the height of the 500 mb level. There is a huge area of greater than 3 standard deviations below average along the coast and offshore of the Pacific Northwest and British Columbia. (Note that in a randomly distributed "bell curve", 99.7% of all observations would be within 3 standard deviations of the average.)


The National Weather Service (NWS) report for Astoria:

AS OF 11 AM THIS MORNING...OVER 5 INCHES OF RAIN HAVE FALLEN ON 
 ASTORIA AIRPORT THIS WEEKEND. THIS RAINFALL HAS SHATTERED NUMEROUS 
 SEPTEMBER RECORDS...REMARKABLE CONSIDERING THAT RECORDS HAVE BEEN 
 KEPT IN ASTORIA SINCE 1890.
 
    RAINFALL RECORDS BROKEN IN ASTORIA
 ----------------------------------------
 
 1. ALL-TIME WETTEST SEPTEMBER ON RECORD...
    1. SEP 2013......... 9.70 INCHES AND COUNTING.
    2. SEP 1906......... 8.66 INCHES.
    3. SEP 1920......... 8.55 INCHES.
    4. SEP 1905......... 7.38 INCHES.
 
 2. WETTEST SEPTEMBER DAY ON RECORD...
    1. SEP 28 2013...... 3.56 INCHES.
    2. SEP 16 1997...... 2.67 INCHES.
    3. SEP 30 1953...... 2.41 INCHES.
    4. SEP 13 1935...... 2.27 INCHES.
 
 3. WETTEST 2-DAY TOTAL FOR SEPTEMBER...TOP 2 NOW SET IN 2013.
    1. SEP 28-29 2013... 5.16 INCHES AND COUNTING.
    2. SEP 27-28 2013... 4.55 INCHES.
    3. SEP 3-4 1913..... 3.46 INCHES.
    4. SEP 16-17 1997... 3.42 INCHES.
 
 4. WETTEST 3-DAY TOTAL FOR SEPTEMBER...
    1. SEP 27-29 2013... 6.15 INCHES AND COUNTING.
    2. SEP 2-4 1913..... 4.31 INCHES. 
    3. SEP 15-17 1997... 4.16 INCHES. 

In Washington state, daily rainfall records were set for September 28 at Seattle-Tacoma, Olympia, Hoquiam, and Quillayute. An inspection of National Climatic Data Center records indicates that the 2.93" at Olympia was not only more than triple the old record, it was also an all-time daily record for September, well above the 1.67 on Sept. 17, 2010. Olympia records began in 1948. The NWS reports:

A RECORD RAINFALL OF 2.93 INCHES WAS SET AT OLYMPIA WA AIRPORT ON
SEP 28TH. THIS BREAKS THE OLD RECORD OF 0.82 SET IN 1971.

A RECORD RAINFALL OF 1.71 INCHES WAS SET AT SEATTLE-TACOMA WA
AIRPORT ON SEP 28TH. THIS BREAKS THE OLD RECORD OF 0.83 SET IN 1948.

A RECORD RAINFALL OF 1.78 INCHES WAS SET AT HOQUIAM WA AIRPORT ON
SEP 28TH. THIS BREAKS THE OLD RECORD OF 1.02 SET IN 1962.

A RECORD RAINFALL OF 1.93 INCHES WAS SET AT QUILLAYUTE WA AIRPORT
ON SEP 28TH. THIS BREAKS THE OLD RECORD OF 1.32 SET IN 1971.

The NWS reported on September 30 that several other locations in Washington and Oregon have set September rainfall records:

1. ASTORIA (1890)...
   1. SEP 2013......... 10.51 INCHES AND COUNTING.
   2. SEP 1906......... 8.66 INCHES.
   3. SEP 1920......... 8.55 INCHES.
   4. SEP 1905......... 7.38 INCHES.
      CLIMATOLOGICAL NORMAL: 2.14 INCHES.

2. EUGENE (1890)...
   1. SEP 2013......... 6.16 INCHES AND COUNTING.
   2. SEP 1927......... 5.21 INCHES.
   3. SEP 1911......... 4.91 INCHES.
   4. SEP 1986......... 4.65 INCHES.
      CLIMATOLOGICAL NORMAL: 1.29 INCHES.

3. HILLSBORO (1929)...
   1. SEP 2013......... 6.10 INCHES AND COUNTING.
   2. SEP 1945......... 3.68 INCHES.
   3. SEP 1982......... 3.46 INCHES.
   4. SEP 1977......... 3.43 INCHES.
      CLIMATOLOGICAL NORMAL: 1.26 INCHES.

4. MCMINNVILLE (1894)...
   1. SEP 1996......... 7.58 INCHES.
   2. SEP 2013......... 5.58 INCHES AND COUNTING
   3. SEP 1901......... 4.83 INCHES.
   4. SEP 1914......... 4.28 INCHES.
      CLIMATOLOGICAL NORMAL: 1.31 INCHES.

5. PORTLAND AIRPORT (1940)...
   1. SEP 2013......... 5.06 INCHES AND COUNTING.
   2. SEP 1986......... 4.30 INCHES.
   3. SEP 1982......... 3.98 INCHES.
   4. SEP 1945......... 3.96 INCHES.
      CLIMATOLOGICAL NORMAL: 1.47 INCHES

6. PORTLAND DOWNTOWN (1872)...
   1. SEP 2013......... 6.21 INCHES AND COUNTING.
   2. SEP 1927......... 5.52 INCHES.
   3. SEP 1911......... 5.19 INCHES.
   4. SEP 1969......... 4.87 INCHES.
      CLIMATOLOGICAL NORMAL: 1.54 INCHES.

7. SALEM (1872)...
   1. SEP 2013......... 6.63 INCHES AND COUNTING.
   2. SEP 1927......... 5.52 INCHES.
   3. SEP 1911......... 5.19 INCHES.
   4. SEP 1969......... 4.87 INCHES.
      CLIMATOLOGICAL NORMAL: 1.28 INCHES.

7. VANCOUVER, WA (1896)...
   1. SEP 2013......... 4.98 INCHES AND COUNTING.
   2. SEP 1911......... 4.88 INCHES.
   3. SEP 1925......... 4.46 INCHES.
   4. SEP 1927......... 4.35 INCHES.
      CLIMATOLOGICAL NORMAL: 1.56 INCHES.

Super Summer Soaker Phloods Philadelphia Rainfall Record; Second Extreme in 3 Years

Images (click to enlarge): Top 10 wettest summers in Philadelphia, CapitalClimate chart from National Weather Service (NWS) data; Philadelphia precipitation percentage of normal for 90 days ending August 12, 2013, from NWS

There's a good reason if the Philadelphia Phanatic is looking greener than usual lately. After the summer rainfall record was broken just 1 day into August, another 2.02" this morning has pushed the Philadelphia seasonal precipitation total even further into record territory. With over 2 weeks left, the unofficial June-August rainfall total of 27.56" is barely less than 3" above the old record of 24.58" set just 2 years ago. The seasonal total to date is 245% of the climatological average for the entire 3 summer months.

San Juan Swamps Century-Plus Rainfall Record

Image (click to enlarge): Puerto Rico 24-hour precipitation ending 8 am EDT, July 19, 2013, from National Weather Service

Midnight Update: The final daily rainfall for San Juan is 9.23", the second highest for any day on record.

The year-to-date rainfall total is now 185% of normal and only about 8" below the normal for the entire year. If San Juan were to tie the record low rainfall for each of the remaining 5 months in the year, it would still finish 2013 less than 1" below normal.

5 PM Update: It's baaack! With 0.67" more in this hour, the total of 9.11" is now the second highest for any day in San Juan history and a little more than half an inch from the top spot. Moderate rain continues.

4 PM Update: Rain ended with only 0.02" in the past hour, but less than half an inch in the rest of the day would make second place on San Juan's all-time daily record list. The NWS reports that more is on the way.

The monthly total of 11.64" also breaks the old July record of 11.08" just 2 years ago.

3 PM Update: Another 1.91" in the past hour brings the San Juan daily rainfall total to 8.42", which is the second highest for any summer day and the 4th highest of all time.

2 PM Update: With light rain continuing to fall, the daily total so far is now 6.51", which is the 10th highest for any day in any month. The previous top 10 San Juan daily rainfall amounts:

15-Aug 9.67 in 1944
18-Sep 8.84 in 1989
14-Dec 8.84 in 1910
10-Sep 8.20 in 1996
11-Nov 7.92 in 1931
13-Sep 7.39 in 1928
15-Apr 7.10 in 1988
25-Nov 7.07 in 1979
12-Dec 6.96 in 1981
7-Apr 6.19 in 1915 

Original Post:
Puerto Rico should get a lot of heavy downpours in the summer with tropical cyclones, right? Well, with no organized tropical system whatever, San Juan has just smashed its all-time July daily rainfall record. The National Weather Service reports that the 4.92" so far today has exceeded by a wide margin the old record for July 18 of 3.19", set in 1950. As of that report, heavy rain was still falling.

Today's amount is also well above the old daily record for July of 4.04" on July 7, 1901. It's only the 5th time July daily precipitation has exceeded 3" in a climate history which began in 1898.

The previous top 5 July daily rainfall amounts for San Juan, from the National Climatic Data Center:

7-Jul 4.04 in 1901
23-Jul 3.66 in 1926
18-Jul 3.19 in 1950
12-Jul 3.01 in 1905
24-Jul 3.00 in 1949 

Record Heat in Northern Maine, Eastern Canada

Image (click to enlarge): U.S. temperatures at 4 pm EDT, July 15, 2013, from Unisys

Record heat extended from northernmost Maine into eastern Canada on Monday, July 15:
- The high temperature at Millinocket of 94° tied the record for the date set in 1952.
- The 94° also at Caribou broke the record of 93° set in 1952 and tied in 1968. It was also the hottest day there since July 20, 1991. Caribou climate records began in 1939.
- The CBC reports that St. John's, Newfoundland had its second hottest temperature for any day since records began there in 1942. The 31.2°C (88°F) high was only slightly below the all-time record of 31.5°C on July 6, 1983.

Caribou also broke a record the previous day with 91°, which beat the 90° in 1943.

Record Rainfall Drenches Dulles; Update: Rain Ransacks Roanoke Record

Images (click to enlarge): Washington, DC regional radar, 12:49 am EDT, July 12, 2013, from The Weather Channel; 24-hour precipitation ending 8 am EDT, July 13, 2013, for Washington region, from National Weather Service

2 PM EDT Update: The 3.88" a day earlier (July 10) at Roanoke smashed the daily record of 2.67" in 1931. It was also a new all-time July daily record in a climate history which began over a century ago in 1912. Daily amounts of 3" or more had been observed only twice before in July at Roanoke.

The 1.84" at Richmond also broke a July 10 record of 1.36" set just last year.

To the north, the 2.44" at Pittsburgh beat the daily record of 1.81" in 1958.

10 AM EDT Update: The preliminary July 11 record daily total rainfall for Dulles is 3.71". The 24-hour total ending at 8 am is 4.49", with some light rain continuing.

2 AM EDT Update: Dulles has added 0.22" from lighter thundershowers in the past hour for a storm total so far of 3.79". The reported month-to-date total is now 370% of normal.

Original Post:
Persistent thunderstorms Thursday evening have produced record rainfall in the Virginia suburbs of Washington, DC. At Dulles Airport, the unofficial total of 3.61" through midnight (standard time) was over 3 times the old record for July 11 of 1.12" in 1977. Climate records at Dulles date back only a half-century to 1962, but this was also enough to beat the all-time July daily record of 3.50" on July 27, 1994.

The official climate record for Washington, DC, which began in 1871, shows that July daily rainfalls of 4" or more have occurred on at least 3 occasions:
4.69", July 9, 1970
4.35", July 22, 1969
4.25", July 30, 1878

Southwest Scorched by Historic Heat; Update: All-Time June Records at Death Valley, Needles

Image (click to enlarge): U.S. daily high temperatures, June 28, 2013, from Unisys. Note the bright blue area of 120°+.

July 1 Update: The 129° at the aptly-named Furnace Creek in Death Valley on June 30 was a new all-time June high temperature record there. The previous record of 128° was set on June 29, 1994 and tied on the same date this year. The June 30 reading also tied the all-time June record for the U.S. which was originally set 111 years ago on June 23, 1902 in the former town of Volcano, California.

The June average temperature of 101.3° at Death Valley easily surpassed the old June record of 100.4° in 1960. The June average daily minimum of 87.1° also set a record, exceeding the 86.8° in 1977.

At Needles, California, where climate history extends back to 1888, all-time June records were set for:
- Average temperature of 95.8° (old record 94.8° in 1994)
- Monthly maximum 123° on the 29th (old record 122° on June 11, 1918 and June 29, 1924)
- Average minimum 81.5° (old record 81.0° in 1981)

June 30, 5 PM PDT Update: As of 5 pm, Las Vegas is reporting a high so far of 117°, which ties the all-time record. The preliminary monthly average of 91.5° smokes the old June record by a full degree.

June 30, 4 PM PDT Update: The current temperature of 116° at Las Vegas ties the all-time June record set on June 15, 1940. This is the third consecutive day of 115°+ at Las Vegas.

Phoenix tied its record for June 30 at 115°.

June 29, 9 PM Update: More major heat records were set today. Some preliminary highlights:
- The 115° at Las Vegas tied the record for the date.
- Needles, California hit 123°, which set a new all-time June record in a climate history extending back to 1888.
- Kingman, Arizona beat its old June all-time high by 2° in a climate record which began in 1901.
- Salt Lake City had 105° for the second consecutive day. This was a new all-time June record.

June 29, 10 AM Update: The National Weather Service has provided additional record reports for Needles and Death Valley, California and Kingman, Arizona, included in the table below.

The 115° at Las Vegas was the first time that level was reached in June since 1994. It was also the hottest June temperature at Needles since 1994. At Kingman, it was the second earliest 110° temperature; the earliest was June 16, 1917. That also ties the all-time June record.

Original Post:
It was historically hot in the desert Southwest today. Over a dozen major National Weather Service climate locations in Arizona, Nevada and interior California tied or broke temperature records for June 28, in some cases by big margins. The highest readings in absolute terms were 118° at Palm Springs, California, which tied its 1979 record, and at Yuma, Arizona. Yuma climate records began nearly 140 years ago, in 1876. The previous record of 116° was tied 3 times, but it was soundly broken by a margin of 2°. At Winnemucca, Nevada the previous record of 101° was set just 3 years ago in a climate history which dates back to 1877, but this was surpassed by an impressive margin of 4°.

Here's a preliminary summary of today's records (POR indicates first year of period of record):

	Location	Record	Previous	Date	POR
AZ	Flagstaff	96	94	1990/1974	1898
	Winslow	107	104	1973	1898
	Prescott	104	100	1990	1948
	Yuma	118	116	1994/1990/1985	1876
	Kingman	110	107	1914	1901
NV	Elko	103	101	1892	1888
	Eureka	100	95	2010/2007	1963
	Tonopah	101	101	1956	1954
	Winnemucca	105	101	2010	1877
	Las Vegas	115	115	1994	1937
	Reno	103	100	2010	1888
CA	Bishop	107	105	1956	1943
	Palm Springs	118	118	1979	1893
	Death Valley	125	125	1994	1911
	Needles	121	119	1994	1888