Saturday, December 1, 2012

Pacific Coast Rainfall Record Update: Focus Shifts to Central California;
133-Year San Francisco Record Broken

The focus of record-breaking rainfall shifted southward to central California on Friday. At downtown San Francisco, where climate records began in 1850, the 1.39" broke a 133-year-old record for November 30 of 1.38" in 1879. (The airport's 1.96" failed to reach the record of 2.39" in 1973, however.) Other record rainfall amounts in the region (previous record and date in parentheses):
Livermore       1.85" (0.75", 1982)
Moffett Field   1.40" (1.31", 1973)
Oakland         1.88" (1.58", 1961)
San Jose        1.14" (0.95", 1997)    
Salinas         2.22" (1.49", 1982)
The 2.17" at Santa Rosa was also a record, but climate data there began only in 1998. Records also extended inland. The National Weather Service reports:
SACRAMENTO EXECUTIVE AIRPORT   
1.68 INCHES...OLD RECORD 1.04 IN 1973  
  
STOCKTON AIRPORT  
1.39 INCHES...OLD RECORD 0.64 IN 1997  
  
MODESTO AIRPORT  
0.80 INCHES...OLD RECORD 0.66 IN 1997  

A RECORD RAINFALL OF 0.62 INCH(ES) WAS SET AT FRESNO CA YESTERDAY.   
THIS BREAKS THE OLD RECORD OF 0.50 SET IN 1982.  

Thursday, November 29, 2012

Record Northern Pacific Coast Rainfall

Image (click to enlarge): Northern California precipitation for 24 hours ending at 5 am PST, November 30, 2012, from National Weather Service

November 30 Update: Crescent City peaked out at 4.14" of rain yesterday, more than doubling the old record. Ukiah almost doubled its old record with 2.48", vs. 1.42" in 1938.

Other record reports from the National Weather Service:
A RECORD RAINFALL OF 2.22 INCH(ES) WAS SET AT MEDFORD OR YESTERDAY.   
THIS BREAKS THE OLD RECORD OF 1.25 SET IN 1917.  

A RECORD RAINFALL OF 1.6 INCH(ES) WAS SET AT ROSEBURG OR YESTERDAY.   
THIS BREAKS THE OLD RECORD OF 1.43 SET IN 1951.  
Original post:
The heavy rains pounding the Pacific Coast have already set daily records at several locations in northern California and Oregon as of early this evening. The National Weather Service reports:
..RECORD RAINFALL SET AT CRESCENT CITY CA  
A RECORD RAINFALL AMOUNT OF 2.50 INCHES HAS FALLEN SO FAR TODAY.   
THIS BREAKS THE PREVIOUS RECORD AMOUNT OF 2.00 INCHES SET IN 1995.  
Since that report was issued at 4 pm local time, over one and a half inches of additional rain has been unofficially reported. Crescent City climate records began in 1894.

At Mt. Shasta, the 1.69" as of 4 pm was closing in on the record of 1.81" from 1932, and since then at least three-quarters of an inch of additional rain has fallen.

In Oregon, Medford's 1.58" as of 4 pm was enough to break the record of 1.25" from 1917.




Washington's 7th Driest November;
Second Biggest October/November Relative Decrease


November 30, 5 PM Update: Added 2012 monthly data and charts.

Original post:
With the mere 0.06" of light rain on Tuesday, November 2012 will close out tomorrow with only 0.60" of precipitation at Washington. That ties it with 1908 as the 7th driest November in 143 years of climate history. The driest was in 1981, when 0.29" was reported.

This exceptionally dry month, following the 5.82" drenching in October, represents slightly less than a 90% month-to-month decrease, second only to the 92% in 1981. In absolute terms, the 5.22" rainfall reduction is the 5th largest on record. The largest absolute October-November decrease was 7.49" in 2005, following the all-time wettest October.

Following wetter-than-average months in September and October, this is now the 9th month of 2012 with below-average precipitation. The November departure of 81% below average is followed by March with a 71% deficit.

The 29.42" total precipitation through the first 11 months is over 7" below the average amount to date. If December rainfall is equal to climatology, the annual amount (marked "Climo" on the chart) will remain the second driest since 2000, behind the 29.95" in 2001. Of the 13 years so far this century, only 4 others have been below average.

November was very dry throughout the Mid-Atlantic region, with nearly all areas below 50% of normal. Large areas from Washington eastward and southward have been below 25% of normal. The 0.71" at Baltimore is less than 22% of normal, and the 1.12" at Dulles is 33% of normal. Richmond's 0.27" is 8% of normal and the 5th driest in records dating back to 1872.






Seasonal Outlook

Latest seasonal forecast: Click here.


Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.