Weather forecast for Monday February 14

February 14, 2011

By JOHN LINDSEY from PG&E

SEA SWELL:

Today’s 4 to 6-foot west-northwesterly (285-degree deep-water) swell (with an 11 to 13-second period) will continue at this height and period through tonight, increasing to 5 to 7-feet on Tuesday.

Combined with this west-northwesterly swell will be 3- to 4-foot southerly (180-degree shallow-water) seas today into Tuesday.

A series of storms in the Gulf of Alaska will produce an 8 to 10 foot west-northwesterly (285-degree deep-water) swell (with a 12 to 14-second period) on Wednesday morning, increasing to 11 to 13-feet (with 13 to 15-second period) by Wednesday afternoon.

This 11 to 13-foot (285-degree deep-water) swell will remain at this height and period through Thursday, decreasing to 8 to 10-feet (with an 11 to 13-second period) on Friday into Saturday.

Combined with this west-northwesterly swell will be 5 to 7-foot southerly (180-degree shallow-water) seas on Friday.

An 8 to 10-foot northwesterly (310-degree deep-water) sea and swell (with a 7 to 14-second period) is forecast along our coastline on Sunday through next Monday.

PG&E San Francisco Met Office predicted temps:

Inland Temperatures, Paso Robles

Actual                    Predicted

Sun           Mon         Tue         Wed         Thu         Fri         Sat         Sun         Mon
26-72    40-62     41-63      46-55     34-54    36-54   39-56   38-59      36-57

Coastal Valleys Temperatures, San Luis Obispo

Sun          Mon          Tue         Wed         Thu         Fri         Sat         Sun         Mon
34-66    46-62      46-62     48-56     37-57    40-55   41-56    38-60    40-58

ATMOSPHERIC CONDITION:

The Eastern Pacific high has moved southward towards the Baja Peninsula. At the same, the strong high pressure ridge responsible for the dry, clear and warm weather during the first part of February has weakened and migrated westward. This condition has produced a major change in the weather pattern.

A 997-millibar low pressure system 200 miles west of Point Arena will continue to steer scattered rain showers over the Central Coast today into tomorrow along with moderate to fresh (13 and 24 mph) southeasterly winds. Most of the rain will remain north of Monterey Bay during this period.

This week’s high temperatures will only reach the mid 50s with overnight lows in the 40s.

A 1,001-millibar low will drop out of the Gulf of Alaska later Tuesday, and the aforementioned cold front will finally move over the Central Coast from north to south Wednesday with increasing southerly winds and rain.

At this time, rainfall totals should range between 0.75 and 1.25 inches by Wednesday night. Snow is expected across the Sierra, with snow levels initially at 5,500 feet, then dropping to 3,000 feet or possibly lower by Wednesday.

A break in the wet weather should develop Thursday. However, another stronger storm system is forecast to reach the Central Coast on Friday with gale force southerly winds and periods of heavy rain. Rain will turn to showers on Saturday morning, ending by Saturday afternoon.

A steep pressure gradient will produce on strong to gale force (25 and 38 mph) northwesterly winds and clearing on Sunday through Monday. Another strong and cold low pressure system should follow next Tuesday as the storm door is wide open through the end of the month or possibly longer.

DIABLO CANYON AIR TEMPERATURES:

Diablo Canyon Meteorological Tower Air Temperature Data

Yesterday’s         Today’s          Tomorrow’s
Min    Max        Min    Max         Min     Max
52.7°  56.2°      51.1°   55.0°      52.0     54.0

WINDS:

Today’s fresh to strong (19 to 31 mph) southeasterly winds will decrease tonight into Tuesday afternoon.

Fresh to strong (19 to 31 mph) southerly winds are forecast on Tuesday night into Wednesday, decreasing on Thursday.

Strong to gale (25 to 38-mph) southerly winds will develop on Friday decreasing on Saturday.

Strong to gale (25 to 38-mph) northwesterly winds are forecast on Sunday into Monday.

DIABLO CANYON METEOROLOGICAL TOWER WIND DATA:

Today’s winds:

Max peak winds:      SE       28.4 mph at   6:15 a.m.
Max sustained wind:  SE       20.1 mph at   9:15 a.m.

Yesterday’s Maximum Winds:

Max peak winds:      SE       13.2 mph at  11:45 p.m.
Max sustained wind:  SE       10.7 mph at  11:45 p.m.

SEAWATER TEMPERATURES:

The Diablo Canyon waverider buoy is reporting a sea surface temperature of 54.5 degrees while the Nortek AWAC current meter is reporting 54.2 degrees.

Intake seawater temperatures will range between 53 and 55 -degrees through Friday.

OCEAN CURRENTS:

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

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

SEAWATER VISIBILITY:

Seawater visibility was 14 to 16 feet at the Diablo Canyon Intake.

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24-Hour Ocean Condition Outlook for Monday 02/14 to Tuesday 02/15

Sea/Swell       DIR. WNW     HT.   4-6   PER.  11-13  This morning
Remaining  at:  DIR. WNW     HT.   4-6   PER.  11-13  This afternoon
Remaining  at:  DIR. WNW     HT.   4-6   PER.  11-13  Tonight

(Combined with:  DIR. S       HT.   3-4   PER.   4-6   All day)

WINDS:          DIR. SE      SPEED 20-25 + 30         This morning
Remaining  at:  DIR. SE      SPEED 20-25 + 30         This afternoon
Decreasing to:  DIR. S       SPEED 15-20 + 25         Tonight
===========================================================================
48-Hour Ocean Condition Outlook for Tuesday 02/15 to Wednesday 02/16

Sea/Swell       DIR. WNW     HT.   5-7   PER.  11-13  Tuesday morning
Remaining  at:  DIR. WNW     HT.   5-7   PER.  11-13  Tuesday afternoon
Remaining  at:  DIR. WNW     HT.   5-7   PER.  11-13  Tuesday night

WINDS:          DIR. SE      SPEED 15-20              Tuesday morning
Decreasing to:  DIR. SW      SPEED 10-15              Tuesday afternoon
Increasing to:  DIR. SE      SPEED 20-25 + 30         Tuesday night
===========================================================================

Extended Ocean Condition Outlook:

A steep pressure gradient will produce on strong to gale force (24 and 38 mph) northwesterly winds and clearing on Sunday through Monday. Another strong and cold low pressure system should follow next Tuesday as the storm door is wide open through the end of the month or possibly longer.

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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
02    10    0413     4.4       17            261          53.2
02    11    1443     4.2       13            268          60.8
02    12    1243     3.0       12            261          60.1
02    13    1943     5.2       14            258          55.8
02    14    0813     3.9       13            263          54.5

(cm) (sec)  22+   20    17    15    13     11    9    7
———————————————————————–
02 10  0413  133   17     5    46   258    87    70   254   126  135
02 11  1443  128   13     2    16    98   188   432   127    31   54
02 12  1143  100   11     1     6    47   154   102   193    67   42
02 13  1943  159   13     2     4    19   392   515   454   119   52
02 14  0813  120   13     2     5    17    98   295   203   100  139

Daily Swell Inspection Program

NAME                      DAY   TIME    HEIGHT   PERIOD     SST
(PST)   (FEET)  (SECONDS) (DEG. F)
# 166  Ocean Station Papa      14    0402      17       12       42.4
# 06   SE Papa                 14    0850      15       12       53.6
# 59   California Buoy         14    0850      16       10       56.7
# 01   Point Reyes Waverider   14    0846      11        7       51.8
# 15   Monterey Waverider Buoy 14    0850       5       12       52.7
# 28   Cape San Martin, Ca     14    0850       6       12       54.7
# 50   DCPP Waverider Buoy, Ca 14    0813       4       13       54.5
# 63   Harvest Buoy            14    0820       5       13       55.0
# 01   NW Hawaii               14    0850      10       10       73.9

* 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     1000   0.01 inches

Precipitation this rain season (July 1 – June 30): 17.67 inches
Average season rainfall at DIP to date:            15.34 inches

Ocean Lab Barometer:   30.10 in/Hg or 1019.2 mb  +0.4 mb (Rising)

Sunrise and Sunset

Today’s         Sunrise 6:50 AM      Sunset 5:44  PM
Tomorrow’s      Sunrise 6:49 AM      Sunset 5:45  PM

Tides:
Low Tide                 High Tide
AM          PM           AM          PM
14 Monday     —–  —    1:42 -0.5    6:09 5.6    8:24  3.7
15 Tuesday    12:46  2.4    2:19 -0.8    7:00 6.0    8:52  4.0
16 Wednesday   1:39  2.0    2:55 -1.0    7:49 6.2    9:22  4.3
17 Thursday    2:30  1.6    3:31 -1.0    8:37 6.2    9:53  4.7
18 Friday      3:20  1.2    4:06 -0.8    9:25 6.1   10:27  5.1
19 Saturday    4:12  0.8    4:42 -0.4   10:15 5.7   11:03  5.4
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
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This day in weather history

1899 – A great blizzard struck the eastern U.S. Washington D.C. received 20.5 inches of snow to bring their total snow depth to nearly three feet. The storm produced 36 inches
of snow at Cape May NJ. (David Ludlum)

1940 – A “Saint Valentine’s Day Blizzard” hit the northeastern U.S. Up to a foot and a half of snow blanketed southern New England, and whole gales accompanied the heavy snow stranding many in downtown Boston. (David Ludlum)

1987 – A powerful storm spawned severe thunderstorms in Texas and Oklahoma, and produced heavy snow in the Rocky Mountain Region. Snowfall totals in Colorado ranged up to 27 inches at Telluride. Straight line winds gusting to 104 mph howled through Guadalupe Pass in West Texas. (The National Weather Summary) (Storm Data)

2009 – Scatted rain showers will continue to pass over our area this morning but will taper-off by this afternoon as a weak transitory high pressure ridge moves over the Diablo Canyon area.

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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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