PG&E weather forecast for Friday January 22

January 28, 2011

By JOHN LINDSEY from PG&E

SEA SWELL:

Increasing northwesterly winds along our coastline will generate a 5 to 7-foot northwesterly (300-degree deep-water) sea and swell (with a 4 to 14-second period) along our coastline today through Saturday.

A 6 to 8-foot northwesterly (295-degree deep-water) swell (with an 11 to 20-second period) will arrive along the Central Coast on Sunday, increasing to 8 to 10-feet (with an 11 to 15-second period) on Monday.

A 5 to 7-foot northwesterly (295-degree deep-water) swell (with an 11 to 14-second period) is forecast along our coastline on Tuesday, decreasing to 3 to 5-feet on Wednesday.

A 6 to 8-foot west-northwesterly (280-degree deep-water) swell (with a 16 to 18-second period) will arrive along the Central Coast on Thursday, increasing to 7 to 9-feet (with a 15 to 17-second period) next Friday.

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Thu         Fri        Sat       Sun        Mon        Tue        Wed        Thu        Fri
32-74     33-67  36-62   42-55      36-55     34-55      32-58      32-60    31-63

Coastal Valleys Temperatures, San Luis Obispo

Thu         Fri        Sat        Sun        Mon        Tue        Wed        Thu        Fri
36-76     41-71   40-65    42-58     39-61      37-61      34-63      33-64    39-68

ATMOSPHERIC CONDITION:

A major change in the weather pattern is underway as the high pressure ridge that has dominated our weather this month briefly breaks down.

This condition is producing moderate to fresh (13 and 24 mph) northwesterly (onshore) winds and briefly allowed the marine layer to redeveloped along our coastline and surge into a few coastal valleys this morning.

This onshore flow will also will lead to cooler temperatures, generally in high 60’s and low 70’s throughout the county today.

The marine layer will reform along our coastline this evening and should move into the coastal valleys tonight into Saturday morning, clearing out by Saturday afternoon.

The marine layer will move back over our area on Saturday night into Sunday morning, producing dense fog and drizzle.

A somewhat cool 1,003 millibar low pressure system and associated cold front will cross our area from west to east later on Sunday with increasing clouds and rain showers. Generally 0.10 and 0.25 inches of rain is expected with most of the rain staying north of San Luis Obispo County. Snow levels will begin in the 4,000 and 5,000 foot range and drop to the 3,000 foot range by Sunday night.

The high pressure ridge will re-build on Monday with a return of night and morning northeasterly (offshore) winds and dry and clear skies throughout the week. Cool minimum temperatures in the 30s are forecast on Monday and Tuesday morning.

A wet pattern may develop by mid February.

DIABLO CANYON AIR TEMPERATURES:

Diablo Canyon Meteorological Tower Air Temperature Data

Yesterday’s          Today’s           Tomorrow’s
Min    Max        Min    Max         Min     Max
53.7°   69.7°     52.3°   63.0°      53.0     59.0

WINDS:

Moderate to fresh (13 to 24 mph) northwesterly winds are forecast today through Saturday, decreasing on Sunday.

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 to 24 mph) levels during the afternoon hours will commence on Monday and will continue through Tuesday.

Gentle to moderate (8 to 18 mph) north to northeasterly (offshore) winds are forecast on Wednesday through next Friday.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      NW       13.4 mph at   7:45 a.m.
Max sustained wind:  NW        7.2 mph at   7:45 a.m.

Yesterday’s Maximum Winds:

Max peak winds:      NW       32.0 mph at   5:15 p.m.
Max sustained wind:  NW       21.5 mph at   5:15 p.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 57.0 degrees while the Nortek AWAC current meter is reporting 53.9 degrees.

Intake seawater temperatures will range between 53 and 55 -degrees through today, decreasing to 52 and 54-degrees on Saturday and remaining at this range through Tuesday.

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 Tuesday.

SEAWATER VISIBILITY:

Seawater visibility was 8 to 10 feet at the Diablo Canyon Intake.

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24-Hour Ocean Condition Outlook for Friday 01/28 to Saturday 01/29

Sea/Swell       DIR. NW      HT.   5-7    PER. 12-14  This morning
Remaining  at:  DIR. NW      HT.   5-7    PER.  4-14  This afternoon
Remaining  at:  DIR. NW      HT.   5-7    PER.  4-14  Tonight

WINDS:          DIR. NW      SPEED 10-15              This morning
Increasing to:  DIR. NW      SPEED 15-20 + 25         This afternoon
Decreasing to:  DIR. NW      SPEED 10-15              Tonight
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48-Hour Ocean Condition Outlook for Saturday 01/29 to Sunday 01/30

Sea/Swell       DIR. NW      HT.   5-7    PER.  4-14  Saturday morning
Remaining  at:  DIR. NW      HT.   5-7    PER.  4-14  Saturday afternoon
Remaining  at:  DIR. NW      HT.   5-7    PER.  4-14  Saturday night

WINDS:          DIR. NW      SPEED 10-15              Saturday morning
Increasing to:  DIR. NW      SPEED 15-20 + 25         Saturday afternoon
Decreasing to:  DIR. NW      SPEED 10-15              Saturday night
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Extended Ocean Condition Outlook:

A somewhat cool 1,003 millibar low pressure system and associated cold front will cross our area from west to east later on Sunday with increasing clouds and rain showers. Generally 0.10 and 0.25 inches of rain is expected with most of the rain staying north of San Luis Obispo County.

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The 24 – Hour Ocean Data From The Diablo Canyon Wave rider Buoy
MONTH  DAY  TIME  SIG.HEIGHT   PERIOD   SWELL DIRECTION     SST
01    25    0543     5.1       14            267          53.4
01    26    0413     4.4       13            268          53.4
01    27    0513     6.7       15            268          53.6
01    28    0713     5.1       13            267          57.0

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————–
01 25  0543  156   13     3    20   101   378   536   249    61  127
01 26  0413  133   13     3    24    26   135   373   203   103  116
01 27  0513  205   15     6    43   247  1263   537   159   136  120
01 28  0713  156   13     2     6    30   343   541   217    89   33

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      28    0402      16       10       42.8
# 06   SE Papa                 28    0750      10       10       54.0
# 59   California Buoy         28    0750       7       13       55.9
# 01   Point Reyes Waverider   28    0746       7       14       52.2
# 15   Monterey Waverider Buoy 28    0750       6       13       53.8
# 28   Cape San Martin, Ca     28    0750       7       14       54.1
# 50   DCPP Waverider Buoy, Ca 28    0713       5       13       55.6
# 63   Harvest Buoy            28    0720       8       14       55.4
# 01   NW Hawaii               28    0750       5       12       74.6

* 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.

Wednesday  1500 through Thursday   1500   0.00 inches
Thursday   1500 through Friday     1500   0.00 inches

Precipitation this rain season (July 1 – June 30): 17.61 inches
Average season rainfall at DIP to date:            12.03 inches

Ocean Lab Barometer:   30.13 in or 1020.3 mb  -0.3 mb (Falling)

Sunrise and Sunset

Today’s         Sunrise 7:05 AM      Sunset 5:27  PM
Tomorrow’s      Sunrise 7:04 AM      Sunset 5:28  PM

Tides:
Low Tide                 High Tide
AM          PM           AM          PM
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
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This day in weather history

1988 – Barometric pressure readings of 30.55 inches at Miami FL, 30.66 inches at Tampa FL, and 30.72 inches at Apalachicola FL were all-time record high readings for those locations.

1989 – Nome, AK, reported an all-time record low reading of 54 degrees below zero, and the temperature at Fairwell AK dipped to 69 degrees below zero. Deadhorse AK reported a morning low of 49 degrees below zero, and with a wind chill reading of 114 degrees below zero.  (Storm Data)

2005 – A fast moving cold front passed over San Luis Obispo, producing 0.42″ of rain. Over the last 14 hours the Diablo Canyon Ocean Lab recorded 0.62″ of precipitation.

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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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