NOVEMBER 2001 WEATHER SUMMARY
(Includes commentary on the 21st-12/2 GOA storm sequence ) See special report
on Leonids 2001 in Archives section
In a word, Windy&Wet (technical term). Our 6.3", while only the 4th wettest
November in my records (to 1984), signaled what may be a generic shift in
our west coast storm track. For the first time (or at least very rarely)
since the drought of '76-'78, deep, windy and wet storms dropped like a
conga-line along the coast from British Columbia to Los Angeles. By Dec.
2, seasonal rainfall totals had climbed >200% of normal in many locations
(228% PON for Pacifica). Most rain fell in two distinct rainy periods
with 11 days of rain overall. The 3 days of rain > 1" with two of
those approaching 2" days was impressive, demonstrating a rejuvenation of
the moisture supply. After a warm and tranquil opening week of the month,
twin lows hit the coast as "uppercuts" from the SW. High rainrates from both
storms, especially storm #2, occurred when cold air invaded the lows right
off the coast. Long moisture plumes from the sub-tropics resembling Pineapple
Connections fueled each low, with the plumes extending down to the vicinity
of 20N. Beginning on the 21st, the second, a more significant (long-term)
pattern developed during the last 10 days or so of the month, extending into
early December (12/1-2) as a progression of increasingly potent GOA lows
swept down the NE side of a well entrenched EPac high anchored between Hawaii
and Baja. High winds accompanied all the lows, indicating good surface
dynamics (as compared to the now dreaded "Upper Level" and "Cutoff" low pressure
patterns of the past few years) with winds topping out at 60mph in Pacifica
on the 24th. This event came right on the heels of a drier but deeper
inside-slider type low passage on the 23rd when winds pummeled the entire
state, reaching 114mph in Kern Country and 80-90mph in the Mojave desert.
Hi winds also occurred with the three big rain makers from the 28th-12/2,
topping out in Pacifica at 59, 54 and 51 mph respectively. Wind gusts over
100mph were noted over the higher Sierra ridges on the 28th and again on
Dec. 2. Minor wind damage occurred over a large area of the State,
and power outages affecting over 500,000 Customers resulted from the blow
on the 24th. During the 21st-Dec. 2 period, almost 9" of
rain fell....over 7" from the 28th thru Dec. 2., with snow to very low elevations
in the north part of the state. On the 28th, over 24" of snow buried NorCal
above 3,500', shutting down I-5 for 12 hrs over a 150 mile stretch.
. Another interesting aspect of rains this month was the dramatic orographic
enhancement of rain totals. Pacifica seems to have been right in "The Zone",
as our 228% PON (12.39") is significantly higher than surrounding areas.
SFO (the airport on the other side of The Peninsula) for instance, is also
wetter than San Francisco, and reflects the older pattern of SFO being wetter
than The City. Note that for most of the non-El Nino years since '76-'78,
The City has averaged more rain than SFO. During many of this year's November
storms, rainfall often ranged from tenths to 2-4" in the immediate Bay Area
depending on the amount of (or lack of) orographic lifting. Both wind
direction and intense surface flows have contributed to this effect. It was
interesting to note that up until the end of the month, rainfall inland and
snowfall in the Sierra were only average at best. However, the Dec 1 &
2 storms ended the "average" aspect of our Winter so far, depositing widespread
3-5' blankets down 5,500', with smaller amounts down to 3,500'. Other
quick notes: High surf has caused enhanced erosion in many locales,
some minor damage to cliffs and the Pacifica Pier, minor flooding
in lower Linda Mar accompanied the 5.3" dump during 24hrs of 12/1-12/2,
convective activity noted on the 24th, 28th and Dec 2nd, pea hail fell on
the 28th and Dec. 2.
MONTHLY CLIMATOLOGICAL SUMMARY for NOV. 2001
NAME: HOME CITY: Pacifica STATE: Ca ELEV: 540' LAT: 37.36'N LONG: 122.27'W
TEMPERATURE (°F), RAIN (in), WIND SPEED (mph)
HEAT COOL AVG
MEAN DEG DEG WIND DOM
DAY TEMP HIGH TIME LOW TIME DAYS DAYS RAIN SPEED HIGH TIME DIR
------------------------------------------------------------------------------------
1 55.9 66.5 1:00p 50.4 8:00a 6.5 0.0 0.01 1.1 11.0 1:00p S
2 55.2 66.0 1:30p 47.9 7:00a 8.0 0.0 0.01 0.9 10.0 1:30p SSW
3 54.1 64.9 1:30p 48.4 7:30a 8.3 0.0 0.00 1.1 9.0 12:00p SSW
4 53.2 64.1 2:00p 47.4 6:30a 9.3 0.0 0.00 1.0 10.0 1:00p SSW
5 55.7 64.8 1:30p 50.7 8:30a 7.3 0.0 0.00 1.7 8.0 10:30a SSW
6 52.9 58.6 2:00p 47.4 12:00m 12.0 0.0 0.00 3.5 18.0 1:00p S
7 55.6 66.6 3:00p 46.3 5:30a 8.6 0.0 0.01 2.6 16.0 12:00p N
8 63.8 72.8 3:00p 58.0 11:00p 0.0 0.4 0.00 3.0 14.0 4:30a S
9 60.4 71.8 1:30p 51.8 12:00m 3.2 0.0 0.00 1.4 9.0 11:00a S
10 57.3 64.6 12:30p 49.3 4:00a 8.1 0.0 1.11 3.5 33.0 3:00p S
11 60.4 62.5 1:30p 58.3 1:00a 4.6 0.0 0.19 8.1 36.0 1:30p S
12 57.2 60.7 12:30a 53.8 8:00p 7.8 0.0 1.84 6.4 36.0 12:30a S
13 56.2 60.3 11:30a 52.5 5:00a 8.6 0.0 0.01 2.5 15.0 12:00p SSW
14 58.9 64.3 12:00p 55.0 12:00m 5.3 0.0 0.00 1.1 8.0 10:30a SSW
15 56.0 62.1 11:30a 53.2 12:00m 7.3 0.0 0.01 1.0 11.0 6:00a SW
16 57.5 64.1 1:00p 52.5 7:00a 6.7 0.0 0.02 1.8 15.0 12:30p S
17 55.0 62.3 2:00p 48.3 7:00a 9.7 0.0 0.01 1.6 15.0 9:30p S
18 57.8 65.1 2:00p 51.7 5:00a 6.6 0.0 0.00 3.0 20.0 9:30a WNW
19 58.6 62.2 4:00p 53.3 6:30a 7.3 0.0 0.02 3.9 27.0 3:00p S
20 61.4 66.9 1:00p 59.0 6:30a 2.0 0.0 0.00 3.0 17.0 11:00p S
21 59.4 61.6 11:30a 58.0 6:00p 5.2 0.0 0.20 7.5 34.0 4:00p S
22 57.7 60.9 1:00p 53.1 11:30p 8.0 0.0 0.00 3.9 24.0 12:30a S
23 54.8 59.1 12:30p 51.0 6:30a 10.0 0.0 0.00 1.7 13.0 12:30p S
24 52.6 59.4 7:30a 46.7 12:00m 11.9 0.0 0.85 8.7 60.0 7:30a S
25 49.3 54.7 2:00p 44.8 3:00a 15.3 0.0 0.02 1.0 9.0 12:30a S
26 49.6 55.6 1:30p 45.1 12:00m 14.7 0.0 0.00 1.4 12.0 12:00p NNW
27 47.9 54.4 3:00p 43.3 6:00a 16.2 0.0 0.00 2.3 17.0 2:00p NE
28 51.2 54.5 11:00a 47.3 12:30a 14.1 0.0 1.86 9.9 59.0 9:00p S
29 52.1 55.8 2:30p 49.3 12:00m 12.5 0.0 0.09 4.6 21.0 7:30p S
30 50.1 56.9 2:30p 44.3 6:00a 14.4 0.0 0.04 1.8 15.0 10:30p SSW
-------------------------------------------------------------------------------------
55.6 72.8 8 43.3 27 259.3 0.4 6.30 3.2 60.0 24 S
Max >= 90.0: 0
Max <= 32.0: 0
Min <= 32.0: 0
Min <= 0.0: 0
Max Rain: 1.86 ON 11/28/01
Days of Rain: 11 (>.01 in) 6 (>.1 in) 3 (>1 in)
Heat Base: 65.0 Cool Base: 65.0 Method: (High + Low) / 2