PG&E weather forecast for Tuesday

January 18, 2011

By John Lindsey from PG&E

SEA SWELL

Today’s 7 to 9-foot west-northwesterly (285-degree deep-water) sea and swell (with a 7 to 20-second period) will build to 9 to 11-feet (with a 7 to 17-second period) on Wednesday.

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 yesterday. 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.

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 next Tuesday.

Preliminary analysis:

Another long-period, west-northwesterly (285-degree deep-water) swell will arrive along our coastline on Jan. 27 and 28.

ATMOSPHERIC CONDITION:

A 1,029 millibar Eastern Pacific High is centered about 450 miles to the west-northwest of San Luis Obispo and is forecast to strengthen to 1,032 millibars over the next 48 hours. This condition will keep the storm track far to the north.

Once again, moderate to fresh (13 to 24 mph) and at time gusty
northeasterly (offshore) winds and unseasonably warm and dry weather
has developed this morning.

At 6 a.m., the low at the Paso Robles Airport was 47 degrees while the temperature at the San Luis Obispo County Airport was 60 degrees.

This morning’s satellite image shows extensive tule fog in the San Joaquin Valley. Bakersfield’s Meadows Field Airport reported a low of 49 degrees and a high of only 51 degrees yesterday.

High temperatures will range from the high 60s to low 70s in the North County (Paso Robles) and along the northwesterly (Morro Bay and Los Osos) facing beaches. High temperatures in the coastal valleys (San Luis Obispo) and along the southwesterly (Avila Beach and Cayucos) facing beaches will reach the low to mid-70s.

Strong to gale force (25 and 38 mph) northwesterly winds along the coastline on Wednesday will produce slightly cooler temperatures throughout the county.

Gentle to moderate (8 and 18 mph) north to northeasterly (offshore) winds will produce mostly clear and warmer weather on Thursday through the weekend. Very dense fog and low clouds are forecast to persist in the San Joaquin Valley.

A dry weather pattern should hold into the middle part of next week or longer.  Still no signs of any widespread rainfall over the next 10 days to two weeks. January 2011 should have below average rainfall.

DIABLO CANYON AIR TEMPERATURES:

Diablo Canyon Meteorological Tower Air Temperature Data

Today’s                Tomorrow’s
Min    Max          Min    Max
55.8    74.5°        57.0°   70.0°

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Mon      Tue      Wed      Thu       Fri        Sat      Sun      Mon      Tue
44-70   42-66   35-64  35-65    32-67    31-67  36-66    34-64   33-66

Coastal Valleys Temperatures, San Luis Obispo

Mon       Tue       Wed      Thu       Fri        Sat       Sun       Mon     Tue
59-77    52-74   45-70    45-72    40-70   40-68   41-70    39-69   40-70

WINDS:

A pattern of moderate to fresh (13 and 24 mph) and at times gusty northeasterly (offshore) winds developing during the night and morning hours, increasing out of northwest to fresh to strong (24 and 31 mph) levels during the afternoon hours will continue through Wednesday morning.

Strong to gale force (25 and 38 mph) northwesterly winds are forecast on Wednesday afternoon.

Gentle to moderate (8 and 18 mph) north to northeasterly (offshore) winds are forecast on Thursday and Friday, shifting out of the northwest on Saturday through next Monday.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      NE       30.3 mph at   6:00 a.m.
Max sustained wind:  NE       17.8 mph at   6:00 a.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 53.4 degrees. The Nortek AWAC current meter is not reporting today.

Intake seawater temperatures will range between 52- and 54 -degrees through Saturday.

OCEAN CURRENTS:

The DCPP Cal Poly CODAR stations are indicating a southerly (offshore) flowing current.

This southerly (offshore) flowing current will continue to flow southward through Saturday.

SEAWATER VISIBILITY:

Seawater visibility was 5 to 7 feet at the Diablo Canyon Intake.

==========================================================================
24-Hour Ocean Condition Outlook for Tuesday 01/18 to Wednesday 01/19

Sea/Swell       DIR. WNW     HT.   7-9    PER.  7-22  This morning
Remaining  at:  DIR. WNW     HT.   7-9    PER.  7-20  This afternoon
Increasing to:  DIR. WNW     HT.   8-10   PER.  7-19  Tonight

WINDS:          DIR. NE      SPEED 15-20 + 30         This morning
Shifting   to:  DIR. NW      SPEED 15-20 + 30         This afternoon
Decreasing to:  DIR. N       SPEED 10-15 + 20         Tonight
===========================================================================
48-Hour Ocean Condition Outlook for Wednesday 01/19 to Thursday 01/20

Sea/Swell       DIR. WNW     HT.   9-11   PER.  7-18  Wednesday morning
Remaining  at:  DIR. WNW     HT.   9-11   PER.  7-17  Wednesday afternoon
Decreasing to:  DIR. WNW     HT.   8-10   PER.  7-17  Wednesday night

WINDS:          DIR. NE      SPEED 10-15 + 20         Wednesday morning
Increasing to:  DIR. NW      SPEED 20-25 + 30         Wednesday afternoon
Decreasing to:  DIR. NW      SPEED 15-20 + 25         Wednesday night
===========================================================================

Extended Ocean Condition Outlook:

A dry weather pattern should hold into the middle part of next week or longer.  Still no signs of any widespread rainfall over the next 10 days to 2 weeks. January 2011 should have below average rainfall.

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

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    0613     8.0       20            255          53.4

(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  0613  243   20   262   816    73   106   241   547   803  394

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)

# 166  Ocean Station Papa      18    0420       8       13       42.6
# 06   SE Papa                 18    0650       8       15       52.3
# 59   California Buoy         18    0650      13       16       56.1
# 01   Point Reyes Waverider   18    0646      13       18       52.0
# 15   Monterey Waverider Buoy 18    0650      10       20       53.6
# 28   Cape San Martin, Ca     18    0650      11       19       53.8
# 50   DCPP Waverider Buoy, Ca 18    0613       8       20       53.4
# 63   Harvest Buoy            18    0620      11       20       54.0
# 01   NW Hawaii               18    0650      11       12       74.1

* 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.

Sunday     1500 through Monday     1500   0.00 inches
Monday     1500 through Tuesday    1500   0.00 inches

Precipitation this rain season (July 1 – June 30): 17.61 inches
Average season rainfall at DIP to date:            10.20 inches

Ocean Lab Barometer:   30.01 in or 1016.2 mb  -0.7 mb (Falling)

Sunrise and Sunset

Today’s         Sunrise 7:10 AM      Sunset 5:17  PM
Tomorrow’s      Sunrise 7:10 AM      Sunset 5:18  PM

Tides:
Low Tide                 High Tide
AM          PM           AM            PM
18 Tuesday     1:46  2.4    3:25 -1.2    8:02 6.4   10:02  4.0
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

1973 – A baby was carried 300 to 400 yards by the strong winds of a tornado at Corey LA, yet received only minor injuries. (David Ludlum)

1990 – A winter storm produced heavy snow and high winds across the southwestern U.S. Snowfall totals ranged up to 18 inches at Lake Arrowhead CA and Ashford AZ. High winds in New Mexico gusted to 100 mph east of Albuquerque. (David Ludlum)

2006 – This morning’s cold front produced 0.09 inches of rain at the Diablo Canyon Ocean Lab. An upper-level trough currently crossing California will continue to produce isolated rain
showers with numerous rainbows throughout our area and thunderstorms over the central valley with frequent lightning strikes.

2008 – The relaxation of the northeasterly (offshore) winds and clear skies have produced cold temperatures this morning with many of our areas reaching below the freezing point.

2010 – Batten down the hatches, A very strong and fast moving low pressure center (972 millibars) has develop about 400 miles to the west of Northern California. The associated cold front will intensify as it moves towards the Central California coastline. The southeasterly winds at Diablo Canyon have reached 40 mph sustained with gust near 50 mph and the surface pressure has fallen rapidly to 29.53 in/Hg or 999 millibars at 10:00 a.m.

As this vigorous cold front approaches our area it will continue to produce moderate gale to fresh gale force (32-46 mph) southerly winds and periods of heavy rain. Frontal passage will occur between 11 a.m. and 1 p.m.

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

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.

Replication of this weather report must be in its entirety. You may view and copy material from this forecast, provided you retain all copyright, trademark, and other proprietary notices displayed on the materials. Use of these materials in publications, radio, television, other media presentations, or other websites is prohibited without PG&E’s express written consent.

PG&E is a subsidiary of PG&E Corporation, one of the largest natural gas and electric utilities in the United States, delivering some of the nation’s cleanest energy to 15 million people in northern and central California. If you would like to subscribe or unsubscribe to this daily
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.