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1998-99 Rainyear in Review 

La Nina influenced 1998-'99 will be remembered as one of the coldest rainyears  in recent memory.  Following on the heels of the record El Nino of '97-'98, this La Nina episode really highlighted the concept that ENSO is a two way oscillation.  1998-'99 featured wild extremes in rainfall as the northern parts of California and points farther north all had very hard winters and record snows, while in SoCal,  only 40% of normal precipatation for the year was common. A majority of storms were in the upper atmosphere...especially in the late Winter/Spring period when a seemingly never ending parade of cutoff lows and troughs brought frigid air and low snow levels to the Sierra. For the season, we didn't experiece a single "Pineapple Connection" or zonal precip pattern as storms moving down the coast then east kept the basic pattern quite progressive. Because of the low snowlevels, and moisture concentrated above 3,000',  near record snows fell in the northern Sierra, and Mt. Bachelor in Oregon set a new North American record with over 98' of snow. Above average snow in the Central Sierra tapered off to below and much below average from Mammoth Lakes south. At sea level, the "generic" dividing line between above and below average rains occurred about the latitude of the Bay Area.  In many storms, a sharp, well defined boundry between heavy and light/moderate rain occurred directly along the latitude of the Golden Gate. San Francisco finished with about 110% of normal,  which was almost 6 inches more rain than did San Francisco Airport (only 85% of normal), a mere 10 miles to the south. Normally, these two locations are with an inch or so of each other. Here in Pacifica about 5 linear miles west of SFO, 27.15" of rain fell, or about 120% of normal (23").  
Temps review: La Nina years generally produce below normal temps locally, and this rainyear was no exception. As El Nino waned and La Nina gained strength, we had a cool, drizzly summer, and didn't experience our normal warm spells until late September, and then only brief, moderate heatwaves occurred. After that, temps moderated and remained relatively normal to slightly above normal until the third week in December, when two major blasts of record/near record frigid arctic air 10 days apart plumetted straight down the central part of the state. The first blast brought record snows to Bakersfield and other normally temperate locations in the southern valley /desert areas with Stockton and Merced also getting a good dusting. Riding along the leading edge of the second air mass was an upper level low that brought a very rare snow (flurries) to Pacifica on the 20th, and points elswhere.  Low temps in the teens were widespread, and a 23F reading was noted in Golden Gate Park on the 21st. Following the snow, temps remained cold and precip was virtually nil for almost a month, before rains restarted in mid-late January. Springtime temps were the coldest in memory, as the upper level lows mentioned earlier kept ushering blast after blast of chilly NPac air..a pattern that would keep up well into the summer.
SST reviews: Starting in late July '98, La Nina's influence was in full swing as SST's fell into the 50's and remained there until Spring of '99, when strong onshore winds and upwelling lowered SST's off the Marin Coast to a very cold 46F. SST off Pacifica was noted at between 48-50F between April and June, with June having the coldest temps. The cold waters brought an expolsion to the baitfish population which had been decimated by the previous El Nino. Sport fishing was seriously affected, as the annual showing of Striped Bass, which generally occurs in late May-early June, had not arrived by the start of July. A possible explaination was that the ocean waters were too cold, and coupled with cold temps in the mountains, freshwater runoff was reduced which kept the fish in the Bay and Delta longer than normal. Contrary to the Bass situation, Salmon fisherman had a fine Spring, with exceptionally large fish for the time of year being noted. In other notes, whales and other large mamals enjoyed a bountiful time food wise, thus somewhat reducing the negative effects of the previous El Nino and subsequent collapse of the local food chain. Everywhere, flora and fauna patterns appear to be still seriously out of whack...many fruit trees hadn't bloomed as of the start of July! As of the start of '99-'00, La Nina appears weakening, but still present, and if previous patterns are followed, this should be a two year event. However, now that El Nino is fully gone away, residual heat and moisture that was used up by this year's storms won't be present, so I suspect we will be entering a much drier year if La Nina remains strong into the next millenium.
 

'98-'99 Rain by Month at My House in Pacifica

1998                                                             
 Jly      Aug     Sep    Oct    Nov     Dec
.03       .02       .19     .96     4.60     1.82

1999
 Jan 
   Feb     Mar   Apr    May    Jun
5.87     6.08    4.03    2.29    .32      .34
Total 27.15"