PG&E weather forecast for Monday January 24

January 24, 2011

By JOHN LINDSEY from PG&E

SEA SWELL:

Today’s 5 to 7-foot west-northwesterly (285-degree deep-water) swell (with a 15 to 17-second period) will decrease to 4 to 6-feet (with a 14 to 16-second period) on Tuesday.

A 5 to 7-foot west-northwesterly (285-degree deep-water) swell (with a 14 to 18-second period) will arrive along our coastline Wednesday, increasing to 6 to 8-feet (with a 13 to 15-second period) on Thursday and will remain at this height and period through Friday.

A 5 to 7-foot northwesterly (295-degree deep-water) sea and swell (with a 5 to 15-second period) will develop along our
our coastline on Saturday.

A 4 to 6-foot northwesterly (295-degree deep-water) swell (with an 11 to 13-second period) is forecast along our coastline on Sunday through next Tuesday.

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Sun      Mon     Tue     Wed     Thu     Fri     Sat    Sun     Mon
36-73    34-67   32-68   34-67   40-66   39-68   39-66  39-64   34-61

Coastal Valleys Temperatures, San Luis Obispo

Sun      Mon     Tue     Wed     Thu     Fri     Sat    Sun     Mon
39-74    44-74   41-74   40-73   40-76   39-74   40-71  39-68   41-65

WINDS:

This morning’s gentle to moderate (8 and 18 mph) northeasterly (offshore) winds will shift out of the northwest and increase to moderate to fresh (13 and 24 mph) levels this afternoon.

Gentle to moderate (8 and 18 mph) northeasterly (offshore) winds are forecast on Tuesday through Thursday, followed by increasing northwesterly winds on Friday through Saturday.

ATMOSPHERIC CONDITION:

This morning’s northeasterly (offshore) winds produced some interesting temperature fluctuations. At 2:15 a.m. the air temperature was 52 degrees at Diablo Canyon.

The northeasterly winds increased to 14 mph sustained with gust to 23 mph and the air temperature shot up to 66 degrees by 3 a.m. That’s a 14 degree increase in just 45 minutes.

A 1,027-millibar Eastern Pacific High is still parked about 500 miles west-northwest of San Luis Obispo and combined with an area of strong high pressure over the Great Basin will produce gentle to moderate (8 to 18 mph) and at times gusty northeasterly (offshore) winds during night and morning hours through Thursday.

These offshore winds will bring clear to hazy skies and warmer afternoon temperatures to the Central Coast today.

The exception will be the San Joaquin Valley. Wet ground and weak drainage off the Sierra will feed tule fog development during the night and morning hours. The fog will lift during the afternoon hours into a low overcast. Tule fog is expected to persist in southern and western San Joaquin Valley through this week.

Also, the winds will shift out of the northwest (onshore) along the coastline this afternoon, allowing marine low clouds to develop along the northwesterly facing beaches of Montaña de Oro, Los Osos and Morro Bay this afternoon int this evening.

High temperatures will range between the high 60s to low 70s in the North County (Paso Robles) and along the northwesterly facing beaches (Morro Bay and Los Osos).

High temperatures in the coastal valleys (San Luis Obispo) and along the southwesterly facing beaches (Avila Beach and Cayucos) will reach the mid to high 70s.

High pressure will weaken over the next couple of days, but not to the point were the current weather pattern will change.

DIABLO CANYON AIR TEMPERATURES:

Diablo Canyon Meteorological Tower Air Temperature Data

Yesterday’s          Today’s           Tomorrow’s
Min    Max        Min    Max         Min     Max
51.3°   63.2°     51.9°   65.8°      52.0     65.0

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      NE       23.3 mph at   3:00 a.m.
Max sustained wind:  NE       13.8 mph at   3:00 a.m.

Yesterday’s Maximum Winds:

Max peak winds:      NE       12.5 mph at   6:15 a.m.
Max sustained wind:  NE        8.7 mph at   6:15 a.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 53.8 degrees while the Nortek AWAC current meter is reporting 53.6 degrees.

Intake seawater temperatures will range between 53 and 55-degrees through Tuesday, increasing to 54 and 56-degrees on Wednesday and remaining at this range through Friday.

OCEAN CURRENTS:

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

This northerly (onshore) flowing current will continue to flow northward through Friday.

SEAWATER VISIBILITY:

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

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24-Hour Ocean Condition Outlook for Monday 01/24 to Tuesday 01/25

Swell           DIR. WNW     HT.   5-7    PER. 15-17  This morning
Remaining  at:  DIR. WNW     HT.   5-7    PER. 15-17  This afternoon
Remaining  at:  DIR. WNW     HT.   5-7    PER. 14-16  Tonight

WINDS:          DIR. NE      SPEED 10-15 + 20         This morning
Increasing to:  DIR. NW      SPEED 15-20 + 25         This afternoon
Decreasing to:  DIR. N       SPEED 10-15              Tonight
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48-Hour Ocean Condition Outlook for Tuesday 01/25 to Wednesday 01/26

Swell           DIR. WNW     HT.   4-6    PER. 14-16  Tuesday morning
Remaining  at:  DIR. WNW     HT.   4-6    PER. 14-16  Tuesday afternoon
Remaining  at:  DIR. WNW     HT.   4-6    PER. 14-16  Tuesday night

WINDS:          DIR. NE      SPEED 10-15 + 20         Tuesday morning
Decreasing to:  DIR. NE      SPEED  5-10              Tuesday afternoon
Increasing to:  DIR. NE      SPEED 10-15              Tuesday night
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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.

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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    21    0413     6.0       22+           263          53.2
01    21    1813     8.0       20            268          57.0
01    22    2043     7.9       17            254          54.5
01    23    0443     7.5       18            254          56.3
01    24    0543     6.1       17            253          53.8

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————–
01 12  0413  184   20   241   505    35   262   244   179   213  235
01 21  0713  170   20   122   623    45   198   173   139   158  178
01 21  1813  243   20    95  1897   587   203   240   151   144  191
01 22  2043  240   17    34   467  1153   756   470   146   124  191
01 23  0443  227   17    27   610   699   643   521   222   116  163
01 24  0543  185   15    11   104   471   498   345   361   136  110

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      24    0402      11       10       42.8
# 06   SE Papa                 24    0550       8       15       52.7
# 59   California Buoy         24    0550       8       14       55.9
# 01   Point Reyes Waverider   24    0546       8       14       52.2
# 15   Monterey Waverider Buoy 24    0550       5       17       53.4
# 28   Cape San Martin, Ca     24    0550       8       15       54.1
# 50   DCPP Waverider Buoy, Ca 24    0543       6       14       53.8
# 63   Harvest Buoy            24    0520       7       17       54.3
# 01   NW Hawaii               24    0550      13       14       75.0

* Note: Height (significant swell height) is the average height ofthe 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.

Saturday   1500 through Sunday     1500   0.00 inches
Sunday     1500 through Monday     1500   0.00 inches

Precipitation this rain season (July 1 – June 30): 17.61 inches
Average season rainfall at DIP to date:            11.28 inches

Ocean Lab Barometer:   30.09 in or 1019.1 mb  +0.0 mb (Steady)

Sunrise and Sunset

Today’s         Sunrise 7:07 AM      Sunset 5:23  PM
Tomorrow’s      Sunrise 7:07 AM      Sunset 5:24  PM

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

1916 – The temperature at Browning MT plunged 100 degrees in just 24 hours, from 44 degrees above zero to 56 degrees below zero. It was a record 24 hour temperature drop for the U.S.(National Severe Storms Forecast Center)

1963 – A great arctic outbreak reached the southern U.S. The cold wave broke many records for duration of cold weather along the Gulf Coast. A reading of 15 degrees below zero at Nashville TN was an all-time record low for that location. (David Ludlum)

1982 – Chinook winds plagued the foothills of southeastern Wyoming and northern and central Colorado for the second straight Sunday. The winds gusted to 140 mph at Wondervu CO, located northeast of Denver. Chinook winds a week earlier produced wind gusts to 137 mph. (Storm Data)

2006-  An offshore flow produced record warm temperatures last night through this morning. This morning’s air temperatures reached 71.8 degrees which was a record high for this day.

2008 – The evolving weather pattern is very similar to that of the 1991  “March Miracle”. A low pressure system moving southward out of  the Gulf of Alaska is expected to stall west of Diablo Canyon where it will entrain moisture from the tropics and intensify to 996 mb (29.41 in/Hg).

This weather system will maintain a continuous southerly flow over the region at mid and upper levels of the atmosphere and tap into subtropical moisture on Friday, bringing the potential for very  heavy rain beginning Friday afternoon through Sunday morning, especially along our coastal areas.

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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 thisforecast is provided by Pacific Weather Analysis, with their permission.

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