Weather forecast for Sunday March 20

March 20, 2011

By JOHN LINDSEY from PG&E

Clearing from the west this evening produced a spectacular sunset.

However, cold and unstable air moving in from the west will produce numerous rain showers tonight through Monday afternoon. Current snow levels are near 3,500 to 4,000 feet north to south.

Another 0.50 to 1.0 inches of rain is expected through Monday with the higher elevations receiving up to two inches of additional rain.

Tuesday is likely to be the calmest day of the next seven, with partly cloudy skies and gentle winds. However, unsettled weather will redevelop Wednesday as yet another low-pressure system moves down the California coastline and produces increasing southerly winds and rain through Thursday.

ATMOSPHERIC CONDITION UPDATE:

Gentle rain blanketed the Central Coast this afternoon.

Saturday and Sunday’s rain fall totals as of 3 p.m.

Arroyo Grande …………………………  2.69″
Atascadero, Heilmann Regional Park ………  2.40″
Atascadero, south side at Micky’s home …..  3.75″
Atascadero, NW side at Dan’s home ……….  2.69″
Baywood Park ………………………….  3.56″
Camp San Luis  ………………………..  4.29″
Cambria ………………………………  2.63″
Cottontail Creek near Cayucos……………  4.55″
Condor Lookout Los Padres National Forest ..  3.58″
Creston at Rich’s Home …………………  2.14″
Davis Peak, north of Avila Beach…………  3.22″
Diablo Canyon …………………………  3.28″
Heritage ……………………………..  3.40″
Hog Canyon near Paso Robles …………….  2.28″
Islay Hill, San Luis Obispo, CA …………  3.95″
Los Osos, George’s home ………………..  4.08″
Morro Bay, Rich’s home …………………  4.20″
Nipomo ……………………………….  3.01″
Oceano ……………………………….  2.63″
Paul’s House (41 West & Toro Creek) ……..  4.20″
Paso Robles Airport ……………………  3.01″
Rocky Butte …………………………..  4.01″
Santa Margarita Fire Department …………  2.69″
San Luis Obispo Water Reclamation Facility .  4.12″
Santa Maria Public Airport ……………..  4.35″
San Luis Obispo County Airport ………….  3.85″
Shandon, CDF Yard ……………………..  2.16″
SLOWeather.com ………………………..  5.24″
Templeton …………………………….  2.63″
Walter Ranch at Dawn’s home …………….  5.25″

Yesterday’s         Today’s          Tomorrow’s
Min    Max        Min    Max         Min     Max
47.8°   54.1°     47.3°   52.4°      45.0     53.0

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Sat     Sun   Mon   Tue   Wed   Thu   Fri   Sat   Sun
42 52   47 52 42 55 40 58 40 52 45 54 47 65 41 65 44 65

Coastal Valleys Temperatures, San Luis Obispo

Sat     Sun   Mon   Tue   Wed   Thu   Fri   Sat   Sun
45 51   48 54 40 56 39 60 41 60 45 59 50 63 41 62 44 63

SEA/SWELL:

This morning’s combined sea and swell peaked at 12.9 feet with a 12-second period from the southwest.

This combined southwesterly sea and swell will gradually decrease through tonight.

A 936-millibar storm with hurricane force winds developed off the Kamchatka Peninsula a few days ago. This storm will produce a 6 to 8-foot northwesterly (300-degree deep-water) swell (with a 20 to 22-second period) along our coastline Monday, increasing to 7 to 9 feet (with an 18 to 20-second period) Tuesday.

Another round of increasing southerly winds will produce 6 to 8- foot southerly (190-degree shallow-water) seas (with a 4 to 6-second period) Wednesday, followed by an 11 to 13-foot
northwesterly (290-degree deep-water) swell (with a 15 to 17-second period) Thursday. This swell will increase to 13 to 15-feet (with a 14 to 16-second period) on Friday.

Arriving from the southern hemisphere:

A 1 to 2-foot southern hemisphere (200-degree deep-water) swell (with a 20 to 22-second period) will arrive along our coastline Wednesday, increasing to 2 to 4 feet (with a 15 to 17-second period) by Thursday.

WINDS:

This evening’s gentle to moderate (8 to 18-mph) southeasterly winds will shift out of the West-northwest on Monday.

These gentle to moderate (8 to 18-mph) will shift out of the southeast on Tuesday.

Strong to gale force (25 to 38-mph) southerly winds are forecast on Wednesday, shifting and decreasing out of the west on Thursday.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      SE       63.5 mph at   1:00 a.m.
Max sustained wind:  SE       49.0 mph at   1:00 a.m.

Yesterday’s Maximum Winds:

Max peak winds:      SE       45.6 mph at   7:30 p.m.
Max sustained wind:  SE       21.9 mph at   7:30 p.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 50.7 degrees while the Nortek AWAC current meter is reporting 50.5 degrees.

Intake seawater temperatures will range between 50 and 52 -degrees through Monday, increasing to 51- and 53-degrees on Tuesday and will remain at this level through Friday.

OCEAN CURRENTS:

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

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

SEAWATER VISIBILITY:

Seawater visibility was 1 to 2 feet at the Diablo Canyon Intake.

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24-Hour Ocean Condition Outlook for Sunday 03/20 to Monday 03/21

Sea/Swell       DIR. SW      HT.  10-12  PER.   4-7   This morning
Decreasing to:  DIR. SW      HT.   7-9   PER.   4-8   This afternoon
Decreasing to:  DIR. SW      HT.   4-6   PER.   5-8   tonight

(Combined with:  DIR. W       HT.   9-11  PER.  13-15  All day)

WINDS:          DIR. SE      SPEED 40-45 + 55         This morning
Decreasing to:  DIR. SW      SPEED 15-20              This afternoon
Decreasing to:  DIR. SW      SPEED 10-15              Tonight
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48-Hour Ocean Condition Outlook for Monday 03/21 to Tuesday 03/22

Sea/Swell       DIR. NW      HT.   6-8   PER.  20-22+ Monday morning
Remaining  at:  DIR. NW      HT.   6-8   PER.  20-22+ Monday afternoon
Increasing to:  DIR. NW      HT.   7-9   PER.  18-20  Monday night

(Combined with:  DIR. WSW     HT.   3-5   PER.   5-8   All day Monday)

WINDS:          DIR. WNW     SPEED  5-10              Monday morning
Increasing to:  DIR. WNW     SPEED 15-20              Monday afternoon
Decreasing to:  DIR. WNW     SPEED 10-15              Monday night
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Extended Ocean Condition Outlook:

Unsettled weather will redevelop on Wednesday as yet another low pressures system moves down the California coastline and produces increasing  southerly winds and rain through Thursday.

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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
03    14    2013    11.6       14            263          50.7
03    15    0443     9.6       15            253          51.4
03    16    0713     7.1       13            267          52.0
03    16    1213     9.5       22+           243          52.2
03    16    2013    10.7       20            267          51.3
03    17    1213     9.4       17            240          52.0
03    18    0843     6.1       12            274          49.3
03    19    0543    11.1       14            271          50.2
03    20    0243    10.1        7            220          50.5
03    20    0643    12.9       12            275          50.9
03    20    1643     9.1       11            253          50.7

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————-
03 14  2013  354   13    20   122   490  1838  2643  1574   540  293
03 15  0443  291   15    16    74   442  1452   844  1005   677  387
03 16  0713  216   13   244   124    67   539   672   463   401  211
03 16  1213  290   13   619   710   167   314  1169  1105   465  460
03 16  2013  325   20    73  1685   683  1271   489   715   473  610
03 17  1213  287   11    15    94   834   592  1043  1203   571  420
03 18  0843  187   11     2     9    28   219   471   714   380  192
03 19  0543  339   15     9    44   193  2176  2025  1128   562  445
03 20  0243  309    7     4     5    10   218   693   603  1289 2304
03 20  0643  393   11     6    12    38   288  1464  2668  2566  851
03 20  1643  278    9     4     4    29   277   858  1198  1264  453

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      20    1202      11       17       41.7
# 06   SE Papa                 20    1650      10       20       49.8
# 59   California Buoy         20    1650      14       10       55.0
# 01   Point Reyes Waverider   20    1646      14       12       52.3
# 15   Monterey Waverider Buoy 20    1650      10       13       54.0
# 28   Cape San Martin, Ca     20    1650      14       13       54.7
# 50   DCPP Waverider Buoy, Ca 20    1643      10        7       50.5
# 63   Harvest Buoy            20    1620      12       11       51.1
# 01   NW Hawaii               20    1650      10       16       73.6

* 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.

Monday    1500 through Tuesday     1500   0.00 inches
Tuesday   1500 through Wednesday   1500   0.04 inches
Thursday  1500 through Friday      1500   0.00 inches
Friday    1500 through Saturday    1500   0.35 inches
Saturday  1500 through Sunday      1500   2.93 inches

Precipitation this rain season (July 1 – June 30): 23.40 inches
Average season rainfall at DIP to date:            21.25 inches

Ocean Lab Barometer:   29.57 in/Hg or 1001.4 mb  -0.5 mb (Falling)

Sunrise and Sunset

Today’s         Sunrise 7:07 AM      Sunset 7:14  PM
Tomorrow’s      Sunrise 7:05 AM      Sunset 7:15  PM

Tides:
Low Tide                 High Tide
AM          PM           AM          PM
20 Sunday      5:07  0.5    5:19  0.2   11:08 5.1   11:43  5.6
21 Monday      6:06  0.4    5:58  0.8   —– —   12:07  4.5
22 Tuesday     7:13  0.4    6:40  1.5   12:26 5.7    1:17  3.8
23 Wednesday   7:56 -0.5    7:13  2.0   12:46 5.8    2:26  3.6
24 Thursday    9:05 -0.3    8:12  2.4    1:36 5.6    3:55  3.3
25 Friday     10:22 -0.1    9:38  2.7    2:37 5.2    5:33  3.4
26 Saturday   11:38 -0.1   11:20  2.7    3:52 4.8    6:51  3.6
27 Sunday     —–  —   12:43  0.0    5:14 4.6    7:43  3.8
28 Monday     12:43  2.4    1:35  0.0    6:29 4.6    8:20  4.0
29 Tuesday     1:42  2.0    2:17  0.1    7:29 4.6    8:50  4.2
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This day in weather history

1948 – The city of Juneau received 31 inches of snow in 24 hours, a record for the Alaska capitol. (20th-21st) (David Ludlum)

1987 – A storm produced blizzard conditions in Wyoming and eastern Nebraska, and severe thunderstorms in central Nebraska. Snowfall totals ranged up to 12 inches at Glenrock WY and Chadron NE. Thunderstorms in central Nebraska produced wind gusts to 69 mph at Valentine, and wind gusts to 76 mph at Bartley. (Storm Data) (The National Weather Summary)

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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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