Weather forecast for Monday April 11

April 11, 2011

By JOHN LINDSEY from PG&E

Earth Day event:

Join PG&E employees this Saturday morning, April 16 to celebrate Earth Day at Montaña de Oro State Park.

Check-in time: 8:30 a.m. Project time: 9:00a.m.-1:00p.m. Location: Spooner Ranch House, Montana de Oro State Park.

The event is one of a number of service projects sponsored by PG&E and the California State Parks Foundation. Please register at the California State Parks Foundation website, www.calparks.org.

Be sure to dress for outdoor work with long pants, long-sleeved shirt, sturdy shoes, hat, gloves and sunscreen. Snacks and a light lunch will be provided. Bring your own refillable water bottle. Rangers will provide tools and supervision.

The weather is looking great for this year’s event.

ATMOSPHERIC CONDITIONS:

The cold upper-level low pressure system that produced the wild April weather Friday with low elevation snow, frost, hail and a few claps of thunder has moved far to the east.

A 1,028-millibar Eastern Pacific High will take a position about 500 miles to the west of San Luis Obispo and will produce strong to gale force (25- to 38-mph) afternoon northwesterly winds along the coastline, so common during spring, through Sunday.

A weak cold front moving southeastward down the California coastline will continue to produce variably cloudy skies today.

Temperatures today will be similar or slightly warmer than on Sunday and with clearing skies tonight, overnight minimums should be slightly colder and mostly in the upper 30s to 40s.

Tuesday should be a mostly sunny day with little change in temperatures followed by increasing clouds and area of fog and drizzle  late Tuesday night into early Wednesday as another cold front moves through our area.

This system will not produce any rain over the Central Coast. However, it should give some light to moderate snow in the Sierra above 4,000 feet.

Temperatures across the Central Coast on Tuesday through Wednesday will be slightly below normal, then high pressure will build into the state bringing night and morning northeasterly (offshore) winds and above normal temperatures, generally in the 70s and 80s Friday through Saturday.

Yesterday’s         Today’s          Tomorrow’s
Min    Max        Min    Max         Min     Max
49.8°   55.4°     49.1°   55.0°      48.0°    56.0°

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Sun       Mon   Tue   Wed   Thu   Fri   Sat   Sun   Mon
35 68     40 69 39 69 38 68 34 72 36 79 44 80 47 83 48 79

Coastal Valleys Temperatures, San Luis Obispo

Sun       Mon   Tue   Wed   Thu   Fri   Sat   Sun   Mon
37 63     43 63 43 63 44 62 44 67 46 68 48 73 50 70 49 70

SEA/SWELL:

Today’s 3- to 5-foot northwesterly (310-degree deep-water) sea and swell (with a 7- to 14-second period) will continue at this height and period through this afternoon, increasing to 5- to 7-feet by tonight.

Strong to gale force (25- to 38-mph) northwesterly winds along the Central Coast will generate 7- to 9-foot northwesterly  (310-degree deep-water) sea and swell (with an 11- to 14-second  period) Tuesday through Wednesday.

This northwesterly sea and swell will decrease to a 5- to 7-foot  level (with a 7- to 12-second period on Thursday through Friday.

WINDS:

A pattern of fresh to strong (25- to 38-mph) northwesterly winds developing during the afternoon hours, decreasing during the night and morning hours will continue through Sunday.

However, the morning winds on Thursday and Friday should be out of the north to northeast (offshore), before shifting
out of the northwest and increasing to strong to gale force levels on Thursday through Friday.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      NE       16.8 mph at    9:45 a.m.
Max sustained wind:  NE        8.5 mph at    9:45 a.m.

Yesterday’s Maximum Winds:

Max peak winds:      NW       32.2 mph at   3:00 p.m.
Max sustained wind:  NW       24.6 mph at   3:00 p.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 50.2 degrees while the Nortek AWAC current meter is reporting 50.0 degrees.

Intake seawater temperatures will range between 48- and 51-degrees through Sunday.

OCEAN CURRENTS:

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

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

SEAWATER VISIBILITY:

Seawater visibility was 15- to 18-feet at the Diablo Canyon Intake.

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24-Hour Ocean Condition Outlook for Monday 04/11 to Tuesday 04/12

Sea/Swell       DIR. NW      HT.   3-5   PER.   7-14  This morning
Remaining  at:  DIR. NW      HT.   3-5   PER.   7-14  This afternoon
Increasing to:  DIR. NW      HT.   5-7   PER.   7-14  Tonight

WINDS:          DIR. NE      SPEED 10-15              This morning
Increasing to:  DIR. NW      SPEED 25-30 + 40         This afternoon
Decreasing to:  DIR. NW      SPEED 20-25 + 30         Tonight
===========================================================================
48-Hour Ocean Condition Outlook for Tuesday 04/12 to Wednesday 04/13

Sea/Swell       DIR. NW      HT.   6-8   PER.   7-14  Tuesday morning
Remaining  at:  DIR. NW      HT.   6-8   PER.   7-13  Tuesday afternoon
Remaining  at:  DIR. NW      HT.   6-8   PER.   7-13  Tuesday night

WINDS:          DIR. NW      SPEED 15-20 + 25         Tuesday morning
Increasing to:  DIR. NW      SPEED 25-30 + 40         Tuesday afternoon
Decreasing to:  DIR. NW      SPEED 20-25 + 30         Tuesday night
===========================================================================

Extended Ocean Condition Outlook:

Little change.

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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
04    06    2313    10.4       15            260          52.7
04    07    1043     7.8       13            263          55.6
04    08    0543     8.6       12            277          50.2
04    09    0213     8.4       12            275          51.1
04    10    0043     6.2       11            285          52.7
04    11    0613     3.7       14            230          50.2

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————
04 06  2313  318    9    18    58   325   908   502   957  1428 1017
04 07  1043  238   13    17    68    53   275   943   526   469  529
04 08  0543  261   11     4    55   184   273   729  1142   752  500
04 09  0213  257   11     3    27   203   210   713  1473   715  330
04 10  0043  189   11     1     8    31    98   251   523   443  446
04 11  0613  112    4     1     3    19    62    85    93    91  294

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      11    0402      13       11       41.7
# 06   SE Papa                 11    0650      11       14       52.2
# 59   California Buoy         11    0650      10       14       55.6
# 01   Point Reyes Waverider   11    0646       6       14       49.8
# 15   Monterey Waverider Buoy 11    0650       3       11       51.6
# 28   Cape San Martin, Ca     11    0650       7       12       55.2
# 50   DCPP Waverider Buoy, Ca 11    0613       4       14       50.2
# 63   Harvest Buoy            11    0620       8       13       52.0
# 01   NW Hawaii               11    0650       9        8       75.6

* 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.

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

Precipitation this rain season (July 1 – June 30): 25.84 inches
Average season rainfall at DIP to date:            23.37 inches

Ocean Lab Barometer:  30.28 in/Hg or 1025.4 mb  +0.5 mb (Rising)
Sunrise and Sunset

Today’s         Sunrise 6:36 AM      Sunset 7:33  PM
Tomorrow’s      Sunrise 6:35 AM      Sunset 7:35  PM

Tides:
Low Tide                 High Tide
AM          PM           AM          PM
11 Monday     11:31  0.0   11:19  2.6    3:40 4.5    6:46  3.5
12 Tuesday    —–  —   12:25 -0.1    5:04 4.4    7:19  3.9
13 Wednesday  12:36  2.1    1:12 -0.1    6:21 4.5    7:50  4.4
14 Thursday    1:36  1.3    1:55  0.0    7:28 4.6    8:21  4.9
15 Friday      2:29  0.6    2:35  0.2    8:29 4.7    8:54  5.4
16 Saturday    3:19 -0.2    3:14  0.5    9:26 4.6    9:29  5.9
17 Sunday      4:09 -0.8    3:54  0.8   10:23 4.5   10:07  6.2
18 Monday      4:58 -1.2    4:34  1.2   11:19 4.3   10:46  6.3
19 Tuesday     5:49 -1.3    5:16  1.6  (12:18 4.1)  11:28  6.2
=========================================================================

This day in weather history

1965 – Severe thunderstorms in the Upper Midwest spawned fifty-one tornadoes killing 256 persons. Indiana, Ohio and Michigan were hardest hit. (David Ludlum)

1988 – Sixteen cities in the western U.S., nine in California, reported new record high temperatures for the date  Afternoon highs of 95 degrees at Sacramento CA and 96 degrees at Bakersfield CA were the warmest of record for so early in the season. (The National Weather Summary)

2010 – The sustained winds at Diablo Canyon have reached 44 mph with gust to 53 mph at 2:15 p.m. this afternoon.

A 995-millibar storm has developed off the Northern California coastline. The associated cold front is swapping in from the Pacific and producing moderate gale to fresh gale (32-46 mph) southeasterly winds this afternoon with gusts reaching 55 mph along the coast.

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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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