Weather forecast for Thursday May 26

May 26, 2011

By JOHN LINDSEY from PG&E

Strong to gale force (25- and 38-mph) northwesterly winds will develop this afternoon and will continue at this level through Saturday.

These onshore winds will produce below normal temperatures along the Central Coast through at least Memorial Day as a persistent upper-level trough of low pressure resides along the west coast.

Mostly clear skies, slightly warmer temperatures in the 60’s and 70’s is expected today.

A dry and cool upper-level low will cross the Central Coast on Saturday and will bring moderate gale- to fresh gale-force (32-mph to 46-mph) northwesterly winds late on Saturday through Sunday along with areas of night and morning marine low clouds.

These winds will usher in a cooler air mass and temperatures will continue to be well below normal through midweek next week. However, a gradual warming trend is expected later in the week.

Yesterday’s            Today’s             Tomorrow’s
Min    Max           Min    Max            Min     Max
48.8°   56.1°        52.4°   59.0°         51.0°    60.0°

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Wed               Thu          Fri          Sat          Sun          Mon          Tue          Wed          Thu
42 75             47 76      49 78     47 76     42 74     42 79      45 77       47 74      45 77

Coastal Valleys Temperatures, San Luis Obispo

Wed               Thu          Fri          Sat          Sun          Mon          Tue          Wed          Thu
44 67             49 69     49 72     47 68     43 69       44 72        47 70      45 70        48 69

SEA/SWELL:

Another round of increasing northwesterly winds will generate a 6- to 8-foot northwesterly (300-degree deep-water) sea and swell (with a 5- to 13-second period) along our coastline this afternoon through tonight, decreasing to 5- to 7-feet (with a 5- to 11-second period on Friday through Saturday.

A 7- to 9-foot northwesterly (310-degree deep-water) sea and swell (with a 7- to 14-second period) is forecast along our coastline on Sunday, decreasing to 5- to 7-feet (with a 7- to
11-second period) on Monday through Wednesday.

Arriving from the Southern Hemisphere:

Another long-period Southern Hemisphere (185-degree deep-water) swell is expected to arrive along our coastline Tuesday at 2- to 4-feet (with a 19- to 21-second period), increasing
to 3- to 5-feet (with a 17- to 19-second period) on Wednesday.

WINDS:

Strong to gale force (25- and 38-mph) northwesterly winds will develop this afternoon and will continue at this level through Saturday, increasing to moderate gale to fresh gale force
(32- to 46-mph) levels on Sunday.

These winds will decrease on Monday through Wednesday.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      N        21.9 mph at    7:45 a.m.
Max sustained wind:  N         9.2 mph at    7:45 a.m.

Yesterday’s Maximum Winds:

Max peak winds:      NW       19.1 mph at    4:00 p.m.
Max sustained wind:  NW       16.3 mph at    4:00 p.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 51.6 degrees. The Nortek AWAC current meter is not reporting this morning.

Seawater temperatures will range between 48- to 51-degrees through Monday.

OCEAN CURRENTS:

Today’s southerly (offshore) flowing current will continue to flow southward through Monday.

SEAWATER VISIBILITY:

Seawater visibility was 22- to 24-feet at the Diablo Canyon Intake.

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24-Hour Ocean Condition Outlook for Thursday 05/26 to Friday 05/27

Sea/Swell       DIR. NW      HT.   3-5   PER.   7-11  This morning
Increasing to:  DIR. NW      HT.   6-8   PER.   5-13  This afternoon
Remaining  at:  DIR. NW      HT.   6-8   PER.   5-13  Tonight

WINDS:          DIR. NW      SPEED 15-20              This morning
Increasing to:  DIR. NW      SPEED 30-35 + 40         This afternoon
Decreasing to:  DIR. NW      SPEED 20-25 + 30         Tonight
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48-Hour Ocean Condition Outlook for Friday 05/27 to Saturday 05/28

Sea/Swell       DIR. NW      HT.   5-7   PER.   7-11  Friday morning
Remaining  at:  DIR. NW      HT.   5-7   PER.   5-15  Friday afternoon
Remaining  at:  DIR. NW      HT.   5-7   PER.   5-15  Friday night

WINDS:          DIR. NW      SPEED 10-15              Friday morning
Increasing to:  DIR. NW      SPEED 30-35 + 40         Friday afternoon
Decreasing to:  DIR. NW      SPEED 20-25 + 30         Friday night
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Extended Ocean Condition Outlook:

Increasing northwesterly winds are forecast on Saturday and Sunday.

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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
05    20    1412     6.6       15            199          54.5
05    21    1842     6.8        8            288          52.7
05    22    1942     8.4        9            286          51.8
05    23    0542     7.7       10            286          50.9
05    24    0712     7.2       14            261          52.7
05    25    0442     4.9       12            268          51.6
05    26    0542     3.9       11            264          51.6

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————
05 20  1412  202    4     5    47   235   495   389   202   292  557
05 21  1842  208    7     5    13    58   286   128    63   328 1182
05 22  1942  255    9     3    19    11    50   150   493  1387 1151
05 23  0542  236    9     3    40    61    70   133   650  1012  922
05 24  0712  220    9     3    14    69   311   396   187   951  428
05 25  0442  150    4     4     6    25    82   258   325   131  349
05 26  0542  119    4     2    14    27    26    49    86   125  360

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      26    0402       9       11       44.4
# 06   SE Papa                 26    0550      12       12       54.7
# 59   California Buoy         26    0550      12       12       54.8
# 01   Point Reyes Waverider   26    0546       6        9       52.5
# 15   Monterey Waverider Buoy 26    0550       4       11       52.0
# 28   Cape San Martin, Ca     26    0550       5       11       55.0
# 50   DCPP Waverider Buoy, Ca 26    0542       4        8       51.6
# 63   Harvest Buoy            26    0520       5       11       51.4
# 01   NW Hawaii               26    0550       8        9       77.5

* 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.

Tuesday   1500 through Wednesday   1500   0.00 inches
Wednesday 1500 through Thursday    1500   0.00 inches

Precipitation this rain season (July 1 – June 30): 26.81 inches
Average season rainfall at DCPP to date:           24.39 inches

Ocean Lab Barometer:   30.12 in/Hg or 1020.1 mb  +0.5 mb (Rising)
Sunrise and Sunset

Today’s         Sunrise 5:52 AM      Sunset 8:08  PM
Tomorrow’s      Sunrise 5:52 AM      Sunset 8:09  PM

Tides:
Low Tide                 High Tide
AM          PM           AM          PM
26 Thursday    1:02  1.6   12:14  1.2    6:28 3.2    7:01  4.7
27 Friday      1:52  1.1   12:53  1.5    7:38 3.1    7:30  4.9
28 Saturday    2:33  0.6    1:29  1.8    8:38 3.2    7:58  5.2
29 Sunday      3:10  0.2    2:03  2.0    9:29 3.3    8:26  5.4
30 Monday      3:45 -0.2    2:37  2.2   10:14 3.4    8:56  5.6
31 Tuesday     4:19 -0.5    3:11  2.3   10:57 3.4    9:28  5.7
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This day in weather history

1988 – There was “frost on the roses” in the Upper Ohio Valley and the Central Appalachian Mountain Region. Thirteen cities reported record low temperatures for the date, including Youngstown OH with a reading of 30 degrees. Evening thunderstorms in North Dakota produced wind gusts to 75 mph at Jamestown.

2006 –  On Tuesday (May 23rd) seawater temperatures reached a high of 58.6°F. Gale force northwesterly winds produced a great amount of upwelling along the Diablo Canyon coastline since Tuesday giving very cold intake seawater temperatures.

Seawater temperatures reached a low of 48.7° F this morning. That’s almost a 10 degree decrease in seawater temperatures in less than 72 hours.

2010 –  A dying frontal system produced sprinkles and a few light rain showers throughout our area yesterday afternoon through early this  morning. San Luis Obispo County Airport reported a couple hundreds of an inch of rain, while the Paso Robles airport and Diablo Canyon only reported a trace.

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