PG&E weather forecast for Wednesday January 19

January 19, 2011

By John Lindsey from PG&E

Emergency tip:

If you see downed power lines,leave the area immediately and then call 911 and PG&E at 1-800-743-5000.

SEA SWELL

Today’s 8 to 10-foot west-northwesterly (285-degree deep-water) sea  and swell (with a 7 to 17-second period) will continue at this height and period through tonight.

A 6 to 8-foot west-northwesterly (285-degree deep-water) swell (with an 11 to 15-second period) will develop along our coastline on Thursday.

A very large 933 millibar storm developed off the Kamchatka Peninsula on Monday. This storm produced hurricane force winds and fully developed seas of nearly 50 feet. Ship reports hundreds of miles away from the center of the storm reported winds of over 50 kts.

Very long-period waves are currently arriving at the NW Hawaii NOAAmarine buoy.

A 7 to 9-foot west-northwesterly (285-degree deep-water) swell (with a 20 to 22-second period) from this massive storm will arrive along the San Luis Obispo coastline Friday, increasing to 10 to 12-feet (with a 17 to 20-second period) on Saturday and will remain at this height but with a shorter period through Sunday.

Note: Swell heights will be higher at the offshore buoys.

This west-northwesterly (285-degree deep-water) swell will decrease to 7 to 9-feet (with a 14 to 16-second period) on Monday, further decreasing to 6 to 8-feet by Tuesday.

A 6 to 8-foot west-northwesterly (285-degree deep-water) swell (with a 14 to 18-second period) is forecast along our coastline next Wednesday, increasing to 7 to 9-feet (with a 13 to 15-second period) next Thursday.

Preliminary analysis:

Another long-period, west-northwesterly (285-degree deep-water) swell will arrive along our coastline on Jan 29.

ATMOSPHERIC CONDITION:

Based on the stability of the current weather pattern (high pressure anchored firmly in the Eastern Pacific) any significant changes are very unlikely before the end of the month.

A few areas of ground fog developed in the North county this morning as the air temperature came within a degree of the dew point. Otherwise, mostly clear skies are forecast throughout San Luis Obispo County today.

Strong to gale force (25 and 38 mph) northwesterly winds along the coastline will produce slightly cooler afternoon temperatures along the beaches and coastal valleys today. A few coastal low clouds may develop along the northwesterly facing (Montana De Oro and Los Osos)
beaches late this afternoon and evening.

A mostly clear night is forecast for tonight with overnight minimums slightly colder than last night’s, especially in the wind sheltered coastal valley locations.

Note: A strong Santa Ana wind event is forecast tonight through tomorrow morning in Southern California.

North to northeasterly (offshore) winds and drier air associated with those winds on Thursday and Friday should produce warmer afternoon temperatures and colder morning lows.

Tule fog and low clouds will probably becoming more extensive this weekend across the San Joaquin Valley.

There are no signs of any rain events for the rest of January and it appears that this month will end up below normal for rainfall after a very wet December.

DIABLO CANYON AIR TEMPERATURES:

Diablo Canyon Meteorological Tower Air Temperature Data

Today’s                Tomorrow’s
Min    Max          Min    Max
57.9    68.5°        52.0°   64.0°

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Tue        Wed     Thu      Fri        Sat       Sun       Mon      Tue      Wed
42-64     34-64   37-65   35-67  34-68  34-66    31-65     32-62   30-65

Coastal Valleys Temperatures, San Luis Obispo

Tue       Wed      Thu      Fri       Sat        Sun       Mon       Tue      Wed
52-71    54-68   47-72   40-71  41-71    43-71     40-70     39-67    37-68

WINDS:

Today’s strong to gale force (25 and 38 mph) northwesterly winds will continue through tonight.

Moderate to fresh (13 and 24 mph) with higher gust north to northeasterly (offshore) winds are forecast on Thursday.

A pattern of gentle to moderate (8 and 18 mph) and at times gusty northeasterly (offshore) winds developing during the night and morning hours, increasing out of northwest to moderate to fresh (13 and 24 mph) levels during the afternoon hours will once again develop on Friday and will continue through Tuesday.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      NW       27.7 mph at   7:15 a.m.
Max sustained wind:  NW       22.6 mph at   7:15 a.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 52.5 degrees while the Nortek AWAC current meter is reporting 52.3 degrees.

Intake seawater temperatures will range between 51- and 53-degrees through Thursday, increasing to 53- and 55-degrees on Friday and remaining at this range through Monday.

OCEAN CURRENTS:

Both the DCPP Cal Poly CODAR stations and the DCPP Nortek AWAC meter are indicating a southerly (offshore) flowing current.

This southerly (offshore) flowing current will continue to flow southward through Thursday, becoming a northerly (onshore) flowing current on Friday through Monday.

SEAWATER VISIBILITY:

Seawater visibility was 2 to 4 feet at the Diablo Canyon Intake.

==========================================================================
24-Hour Ocean Condition Outlook for Wednesday 01/19 to Thursday 01/20

Sea/Swell       DIR. WNW     HT.   8-10   PER.  7-18  This morning
Remaining  at:  DIR. WNW     HT.   8-10   PER.  7-17  This afternoon
Remaining  at:  DIR. WNW     HT.   8-10   PER.  7-16  Tonight

WINDS:          DIR. NW      SPEED 20-25 + 30         This morning
Increasing to:  DIR. NW      SPEED 25-30 + 40         This afternoon
Decreasing to:  DIR. NW      SPEED 15-20 + 25         Tonight
===========================================================================
48-Hour Ocean Condition Outlook for Thursday 01/20 to Friday 01/21

Swell           DIR. WNW     HT.   7-9    PER.  8-16  Thursday morning
Decreasing to:  DIR. WNW     HT.   6-8    PER. 11-15  Thursday afternoon
Decreasing to:  DIR. WNW     HT.   5-7    PER. 11-14  Thursday night

WINDS:          DIR. NNE     SPEED 10-15 + 25         Thursday morning
Decreasing to:  DIR. NE      SPEED 10-15              Thursday afternoon
Increasing to:  DIR. NE      SPEED 15-20 + 25         Thursday night
===========================================================================

Extended Ocean Condition Outlook:

There are no signs of any rain events for the rest of January and it appears that this month will end up below normal for rainfall after a very wet December.

===========================================================================

The 24 – Hour Ocean Data From The Diablo Canyon Wave rider Buoy
MONTH  DAY  TIME  SIG.HEIGHT   PERIOD   SWELL DIRECTION     SST
01    14    2313     4.3       15            255          55.4
01    15    0643     5.2       14            253          52.7
01    16    1113     6.7       15            243          57.6
01    17    0613     6.4       13            258          53.6
01    18    0313     7.6       22+           250          57.2
01    18    0943     9.4       20            261          53.2
01    19    0413     9.2       17            254          52.5

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————–
01 14  2313  132    7     2    13    73   257   168    46    83  142
01 15  0643  159    7     2    13    48   278   326   137   123  221
01 16  2113  200    7     2     7    22   456   548   258   268  358
01 17  0613  195    7     2     5     7   115   484   491   385  324
01 18  0313  233    9   310   387    24    73   376   688   781  333
01 18  0943  286   20   212  2073   204   275   392   393   661  334
01 19  0413  279   17    19   225   889   753   728   549   616  533

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      19    0420      10        8       42.8
# 06   SE Papa                 19    0450       7       13       52.9
# 59   California Buoy         19    0450       9       13       56.1
# 01   Point Reyes Waverider   19    0446      10       15       52.0
# 15   Monterey Waverider Buoy 19    0450       9       17       53.6
# 28   Cape San Martin, Ca     19    0450      13       16       53.4
# 50   DCPP Waverider Buoy, Ca 19    0413       9       17       52.7
# 63   Harvest Buoy            19    0420      11       15       54.3
# 01   NW Hawaii               19    0450       6        9       74.7

* Note: Height (significant swell height) is the average height of the waves in the top third of the wave record. Maximum wave height may be up to TWICE the height in the data shown in the above table.

Precipitation at the Diablo Canyon Ocean Lab.

Monday     1500 through Tuesday    1500   0.00 inches
Tuesday    1500 through Wednesday  1500   0.00 inches

Precipitation this rain season (July 1 – June 30): 17.61 inches
Average season rainfall at DIP to date:            10.38 inches

Ocean Lab Barometer:   30.05 in or 1017.5 mb  -0.3 mb (Falling)

Sunrise and Sunset

Today’s         Sunrise 7:10 AM      Sunset 5:18  PM
Tomorrow’s      Sunrise 7:09 AM      Sunset 5:19  PM

Tides:
Low Tide                 High Tide
AM          PM           AM            PM
19 Wednesday   2:35  2.2    4:01 -1.3    8:46 6.5   10:36  4.2
20 Thursday    3:25  2.0    4:38 -1.2    9:31 6.4   11:11  4.5
21 Friday      4:17  1.8    5:16 -0.9   10:18 6.1   11:49  4.8
22 Saturday    5:14  1.6    5:54 -0.5   11:09 5.6   —–  —
23 Sunday      6:17  1.5    6:33  0.1   12:29 5.0   12:05  4.9
24 Monday      7:30  1.3    7:15  0.8    1:13 5.3    1:11  4.1
25 Tuesday     8:52  1.1    8:02  1.5    2:02 5.4    2:37  3.4
26 Wednesday  10:20  0.7    9:00  2.1    2:57 5.6    4:27  3.1
27 Thursday   11:39  0.2   10:14  2.5    3:58 5.7    6:17  3.2
28 Friday    (12:44 -0.2)  11:32  2.6    5:01 5.8    7:33  3.4
29 Saturday   —–  —-   1:36 -0.5    6:00 5.9    8:24  3.7
30 Sunday     12:39  2.6    2:20 -0.7    6:54 5.9    9:04  3.9
31 Monday      1:33  2.5    2:59 -0.8    7:41 6.0    9:37  4.0
1 Tuesday     2:19  2.3    3:32 -0.7    8:22 5.9   10:06  4.1
=========================================================================

This day in weather history

1933 – Giant Forest CA received 60 inches of snow in just 24 hours, a state record, and the second highest 24 hour total of record for the U.S. (David Ludlum)

1977 – Snowflakes were observed at Homestead and Miami Beach in extreme southern Florida. (David Ludlum)

1989 – The high temperature for the day at Fairbanks, AK, was a frigid 41 degrees below zero, and the morning low of 24 degrees below zero at Anchorage AK was their coldest reading in fourteen years. (National Weather Summary)

2010 – Yesterday’s storm produced 1.21 inches of rain at Diablo Canyon with sustained winds of 40 mph and a gust reaching 56 mph at 11:00 a.m. The strongest winds occurred at Condor
Lookout in the Los Padres National Forest on Hi mountain (3198 feet) which reached 88 mph at 11:00 a.m. Rocky Butte, near San Simeon recorded  4.13 inches

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This weather forecast is a service provided by Pacific Gas and Electric Company (PG&E) to our energy customers. The forecast is valid only for the Diablo Canyon Power Plant coastline area (approximately a one-half mile radius surrounding the plant). Some of the information in this
forecast is provided by Pacific Weather Analysis, with their permission.

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forecast, please send an email to PGEweather@pge.com. Any questions about this forecast please E-mail John Lindsey at jcl5@pge.com or contact by phone at 546-5265. For more information visit, www.pge.com.