Major change in the weather pattern

March 26, 2011

By JOHN LINDSEY from PG&E

The final cold front in a long series of weather systems is sweeping across the Central Coast this afternoon with light rain and gentle to moderate (8 to 18-mph) southerly winds.

Rainfall totals have been sparse with many areas only reporting the few hundreds of an inch to 0.16 inches at SLOWeather.com.

However, our southwesterly facing slopes are reporting significant rain due to orographic enhancement. Diablo Canyon has reported 0.19 inches, further up the coast Cambria at Santa Rosa Creek at Main Street reported 0.88 inches and Rocky Butte near San Simeon reported over 2 inches or rain.

Snow is currently falling at 2,500 feet across the Central Sierra with heavy snow across higher locations. Snow levels should gradually rise through the day today, however as much
as 6 inches of snow could fall as low as 2,500 feet. Another 1 and 2-feet of snow will fall across the higher elevations of the Central Sierra.

A major change in the weather pattern will take place on Sunday as the Eastern Pacific high slides eastward towards the Central Coast, shifting the storm track into the Pacific Northwest and closing the storm door.

Sunday will be partly cloudy but dry with high temperatures mostly in the low 60s.

High pressure will build over our area on Monday and will produce spring-like weather with strong to gale (25 to 31-mph) northwesterly “springtime” winds along the coastline and
temperatures climbing into the 70’s on Tuesday and Wednesday under mostly clear and sunny skies.

At this time, the models and surface charts are indicating a northeasterly (offshore) wind event developing on Thursday and Friday morning. If this condition develops, temperatures
should reach the low 80s throughout San Luis Obispo County during this period.

Yesterday’s         Today’s          Tomorrow’s
Min    Max        Min    Max         Min     Max
46.5°   56.8°     48.6°   54.0°      49.0     57.0

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Fri      Sat   Sun   Mon   Tue   Wed   Fri   Sat   Sun
42 57    47 54 46 62 42 64 37 71 43 75 47 82 51 79 45 70

Coastal Valleys Temperatures, San Luis Obispo

Fri     Sat   Sun   Mon   Tue   Wed   Fri   Sat   Sun
43 59   47 54 46 60 45 62 44 70 48 76 47 81 51 74 48 65

SEA/SWELL:

The swell at the Diablo Canyon waverider buoy peaked at 13.9 feet with a 17 second period yesterday afternoon. The Cape San Martin marine buoy, about 55 nautical miles west-northwest of Morro Bay, reported the peak of the swell at 22 feet with a 16 second period yesterday morning.

Today’s 7 to 9-foot northwesterly (310-degree deep-water) swell (with a 12 to 14-second period) will decrease to 6 to 8-feet on Sunday.

Strong to gale force (25 to 38-mph) northwesterly winds will produce a 6 to 8-foot northwesterly (300-degree deep-water) sea and swell (with a 7 to 11-second period) on Monday and will remain at this height and period through Wednesday.

A 5 to 7-foot northwesterly (310-degree deep-water) swell (with a 7 to 11-second period) is forecast along our coastline on Thursday.

A 959 millibar storm is forecast to develop near the international date line on Monday. If the storm develops as advertised, a 7 to 9-foot northwesterly (290-degree deep-water) swell (with an 18 to 22-second period) will arrive along the Central Coast on Friday, building to 9 to 11-feet (with a 15 to 17-second period) next Saturday.

WINDS:

Today’s gentle to moderate (8 to 18-mph) southeasterly winds will continue through tonight.

Moderate to fresh (13 to 24-mph) northwesterly winds will develop on Sunday morning, increasing to fresh to strong (25 to 31-mph) levels by Sunday afternoon.

Strong to gale force (25 to 38-mph) northwesterly winds are forecast on Monday through Wednesday.

At this time, the models and surface charts are indicating a northeasterly (offshore) wind event developing on Thursday and Friday morning.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      SE       18.1 mph at   3:00 p.m.
Max sustained wind:  SE       15.0 mph at   3:00 p.m.

Yesterday’s Maximum Winds:

Max peak winds:      NW       11.4 mph at   9:30 p.m.
Max sustained wind:  NW        7.8 mph at   9:30 p.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 52.5 degrees while the Nortek AWAC current meter is reporting 52.4 degrees.

Intake seawater temperatures will range between 52 and 54-degrees through Sunday, decreasing to 51 and 53-degrees on Monday. The seawater temperatures will further decrease to
49 and 51-degrees on Tuesday and will remain at this level through next Saturday.

OCEAN CURRENTS:

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

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

A southerly (offshore) current will develop on Monday and will continue to flow southward through next Saturday.

SEAWATER VISIBILITY:

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

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24-Hour Ocean Condition Outlook for Saturday 03/26 to Sunday 03/27

Swell           DIR. NW      HT.   9-11  PER.  13-15  This morning
Decreasing to:  DIR. NW      HT.   7-9   PER.  12-14  This afternoon
Remaining  at:  DIR. NW      HT.   7-9   PER.  12-14  Tonight

WINDS:          DIR. SE      SPEED 10-15              This morning
Increasing to:  DIR. SE      SPEED 15-20              This afternoon
Decreasing to:  DIR. SW      SPEED  5-10              Tonight
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48-Hour Ocean Condition Outlook for Sunday 03/27 to Monday 03/28

Swell           DIR. NW      HT.   6-8   PER.  12-14  Sunday morning
Remaining  at:  DIR. NW      HT.   6-8   PER.  12-14  Sunday afternoon
Remaining  at:  DIR. NW      HT.   6-8   PER.  12-14  Sunday night

WINDS:          DIR. NW      SPEED 10-15              Sunday morning
Increasing to:  DIR. NW      SPEED 20-25 + 30         Sunday afternoon
Decreasing to:  DIR. NW      SPEED 15-20 + 25         Sunday night
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Extended Ocean Condition Outlook:

High pressure will build over our area on Monday and should produce an extended period of dry weather. Strong to gale (25 to 31-mph) northwesterly “springtime” winds are forecast on Monday through Wednesday.

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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    20    0643    12.9       12            275          50.9
03    21    1313     8.9       22+           268          52.5
03    22    0013    11.3       11            278          51.1
03    22    0813     7.0       17            263          50.7
03    23    0343     5.7       15            264          52.0
03    24    2113    10.8       11            284          52.0
03    25    0943    13.9       13            271          53.8
03    25    1243    13.9       17            274          54.5
03    26    1313     7.5       12            272          52.5

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————
03 20  0643  393   11     6    12    38   288  1464  2668  2566  851
03 21  1313  271    9   383   506    36   202   566   920   980  427
03 22  0113  339   20    69  1756   356    82   334  1683  1619  505
03 22  0813  213   17    22   357   518    75   168   499   391  333
03 23  0343  175    4    11    94   165   227   116    40   110  856
03 24  2113  330    9     6    23    95   291   752  1376  1668 1291
03 25  0943  423   13    36   459   979  2357  3192  1606  1183  568
03 25  1243  424   13    46   360  1792  1917  2096  2066  1369  614
03 26  1313  228   13     3     6    41   270   728   627   543  512

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      26    1202      10       10       41.7
# 06   SE Papa                 26    1350      12       13       51.4
# 59   California Buoy         26    1350      12       10       54.9
# 01   Point Reyes Waverider   26    1346      10       12       52.5
# 15   Monterey Waverider Buoy 26    1350       9       13       53.6
# 28   Cape San Martin, Ca     26    1350      10       14       53.4
# 50   DCPP Waverider Buoy, Ca 26    1313       8       11       53.6
# 63   Harvest Buoy            26    1320      11       12       55.0
# 01   NW Hawaii               26    1350       9        9       73.0

* 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   0.99 inches
Wednesday 1500 through Thursday    1500   0.07 inches
Thursday  1500 through Friday      1500   0.55 inches
Friday    1500 through Saturday    1500   0.19 inches

Precipitation this rain season (July 1 – June 30): 25.51 inches
Average season rainfall at DIP to date:            22.05 inches

Ocean Lab Barometer:  29.94 in/Hg or 1013.5 mb  -0.8 mb (Falling)

Sunrise and Sunset

Today’s         Sunrise 6:58 AM      Sunset 7:19  PM
Tomorrow’s      Sunrise 6:57 AM      Sunset 7:20  PM

Tides:
Low Tide                 High Tide
AM          PM           AM          PM
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

1954 – The temperature at Allaket AK plunged to 69 degrees below zero.

1988 – Twenty cities in the southwestern U.S. reported new record high temperatures for the date. Afternoon highs of 73 degrees at Flagstaff AZ, 90 degrees at Sacramento CA, 95 degrees at Santa Maria CA, 95 degrees at Los Angeles CA, 99 degrees at Tucson AZ, and 100 degrees at Phoenix AZ set records for March. (The National Weather Summary)

2008 – This weekends storm produced sustained southeasterly winds of 48.5 mph with gust to 63.1 mph on Saturday afternoon at 16:15 (4:15 pm).

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