======== PG&E DCPP Weather Forecast for Friday 03/12/10 ============ SEA/SWELL: This morning's 5- to 7-foot northwesterly (315-degree deep-water) swell (with a 14- to 16-second period) will increase to 7- to 9-feet by this afternoon and tonight. Another round of northwesterly winds will generate 9- to 11-foot (310-degree deep-water) sea/swell (with a 7- to 14-second period) over the weekend, decreasing to 5- to 7-feet (with an 11- to 13-second period) on Monday. A 969 millibar storm moving towards the Gulf of Alaska will produce a 9- to 11-foot west-northwesterly (295-degree deep-water) swell (with a 16- to 18-second period) along our coastline on Tuesday, increasing to 11- to 13-feet on Wednesday through Thursday. This swell will decrease to 6- to 8-feet (with an 11- to 14-second period) next Friday. Preliminary Analysis long-range forecast: A medium-height west-northwesterly swell could arrive our coastline on March 20. ATMOSPHERIC CONDITION: Today's high temperatures will reached the low to mid 60s. A cold front, currently off the Northern California Coastline, will produce increasing clouds and southerly winds this afternoon with rain reaching the north coast by this evening. Rain will sweep across the rest of the county by tonight. Rain will turn to a few scatted showers on Saturday morning. Rainfall amounts should range between 0.25 and 0.50 inches with snow levels near 4,500 feet with about foot or so of new snowfall possible in the Sierra. An area of high pressure will build behind this cold front and produce a steep pressure gradient along the California coastline. This condition will produce strong to gale force (25-38 mph) northwesterly winds and cool but sunny weather on Saturday afternoon and night. After a clear and cool night Saturday night, Sunday, the first day of Pacific Daylight Time, the winds will decrease and shift out of the north to northeast late Sunday into Tuesday. This offshore flow will warm up temperatures nicely on Monday into Tuesday with maximums reaching into the mid to high 70. These temperatures are well above normal for March. Dry weather will continue throughout next week with near to above normal temperatures. DIABLO CANYON AIR TEMPERATURES: Diablo Canyon Meteorological Tower Air Temperature Data Yesterday's Today's Tomorrow's Min Max Min Max Min Max 47.3° 58.3° 49.6° 60.0° 50.0° 60.0° PG&E San Francisco Met Office predicted temps: Inland Temperatures, Paso Robles Fri Sat Sun Mon Tue Wed Thu Fri 36 63 40 59 29 66 33 74 37 76 42 74 40 75 40 76 Coastal Valleys Temperatures, San Luis Obispo Fri Sat Sun Mon Tue Wed Thu Fri 38 63 43 62 41 69 41 76 42 72 48 72 47 75 45 74 WINDS: This morning's light and variable winds will increase out of the south later this morning. Moderate to fresh (13-24 mph) southerly winds are forecast this afternoon and tonight, followed by another round of strong to gale force (25-38 mph) northwesterly winds on Saturday. The northwesterly winds will decrease to moderate to fresh (13-24 mph) levels early Sunday. North to northeasterly (offshore) winds are forecast late Sunday into Tuesday. Increasing northwesterly winds are forecast on Wednesday and Thursday. Today's winds: Max peak winds: NW 6.0 mph at 7:30 a.m. Max sustained wind: NW 3.6 mph at 7:30 a.m. Yesterday's Winds: Max peak winds: NW 32.0 mph at 2:30 p.m. Max sustained wind: NW 26.4 mph at 2:30 p.m. SEAWATER TEMPERATURES: Gale force northwesterly winds have produced a great amount of upwelling along our coastline. Consequently, seawater temperatures have decreased. The Diablo Canyon waverider buoy is reporting a sea surface temperature of 51.6 degrees while the Nortek AWAC current meter is reporting 51.9 degrees. Intake seawater temperatures will range between 51° and 54° through today, decreasing to 50° to 53° over the weekend. OCEAN CURRENTS: The DCPP Cal Poly CODAR stations and the DCPP Nortek AWAC meter are indicating a northerly (onshore) flowing current this morning. This northerly (onshore) flowing current will continue to flow northward through tonight, becoming southerly (offshore) flowing current over the weekend. SEAWATER VISIBILITY: Seawater visibility was 5 to 7 feet at the Diablo Canyon Intake. ========================================================================== 24-Hour Ocean Condition Outlook for Friday 03/12 to Saturday 03/13 Swell: DIR. NW HT. 5-7 PER. 14-16 This morning Increasing to: DIR. NW HT. 7-9 PER. 11-14 This afternoon Remaining at: DIR. NW HT. 7-9 PER. 11-14 Tonight WINDS: DIR. VAR. SPEED 5-10 This morning Increasing To: DIR. SE SPEED 15-20 This afternoon Increasing to: DIR. SE SPEED 20-25 + 30 Tonight =========================================================================== 48-Hour Ocean Condition Outlook for Saturday 03/13 to Sunday 03/14 Sea/Swell: DIR. NW HT. 9-11 PER. 7-14 Saturday morning Increasing to: DIR. NW HT. 9-11 PER. 7-14 Saturday afternoon Remaining at: DIR. NW HT. 9-11 PER. 7-14 Saturday night WINDS: DIR. NW SPEED 30-35 + 40 Saturday morning Increasing To: DIR. NW SPEED 30-35 + 45 Saturday afternoon Decreasing to: DIR. NW SPEED 20-25 + 30 Saturday night =========================================================================== Extended Ocean Condition Outlook: Northeasterly (offshore) winds will warm up temperatures nicely on Monday into Tuesday with maximums reaching into the mid to high 70s. These temperatures are well above normal for March. ========================================================================== The 24 - Hour Ocean Data From The Diablo Canyon Wave rider Buoy MONTH DAY TIME SIG.HEIGHT PERIOD SWELL DIRECTION SST (PST) (FEET) (SECONDS) (TRUE) (DEG. F) 03 05 0543 6.5 11 274 55.6 03 05 1443 7.6 20 270 55.2 03 06 1013 6.5 15 258 60.1 03 07 1943 8.8 20 277 57.0 03 08 0713 7.4 18 260 55.8 03 09 0513 11.9 11 282 53.6 03 10 0513 5.5 13 270 55.2 03 10 2013 8.6 11 284 53.6 03 11 0443 9.4 13 275 54.5 03 12 0543 5.7 14 267 51.6 (cm) (sec) 22+ 20 17 15 13 11 9 7 ---------------------------------------------------------------------- 03 05 0543 198 9 6 7 17 56 364 596 755 287 03 05 1443 232 20 306 1265 59 29 196 690 340 211 03 06 1013 197 15 6 53 134 815 348 576 232 117 03 07 1913 257 4 124 935 69 160 275 405 471 952 03 08 0713 226 9 10 212 387 91 191 562 805 470 03 09 0513 362 11 7 16 153 278 1065 2482 1882 1061 03 10 0513 168 7 2 4 10 128 267 282 334 363 03 10 2013 263 7 6 35 189 396 525 722 577 1021 03 11 0443 287 13 6 43 81 928 2063 652 482 432 03 12 0543 175 11 5 40 44 273 417 531 250 208 Daily Swell Inspection Program NAME DAY TIME HEIGHT PERIOD SST (PST) (FEET) (SECONDS) (DEG. F) # 75 Shumagin Islands, AK 12 0520 8 11 39.2 # 66 South Aleutians 12 0550 10 12 37.8 # 06 SE PAPA 600NM West Eureka (No current data today) # 59 California Buoy (No current data today) # 01 Point Reyes Waverider 12 0501 17 15 51.8 # 42 Monterey Waverider Buoy 12 0506 6 13 54.3 # 28 Cape San Martin, Ca 12 0550 9 17 55.8 # 50 DCPP Waverider Buoy, Ca 12 0513 6 14 51.6 # 71 Harvest Platform, Ca 12 0530 11 18 52.9 # 01 NW Hawaii 12 0550 9 10 70.2 * Note: Two key buoys off the Northern California coastline have become inoperative over the past year. California marine buoy No. 59, stationed about 357 nautical miles west of San Francisco, went adrift in January 2009 and was recovered in April. Since that time, there have not been any reports from this station. SE Papa marine buoy No. 06, moored about 600 nautical miles west of Eureka at a water depth of more than 13,000 feet, stopped broadcasting on Jan. 9. The California buoy No. 59 should be reinstalled by April if weather conditions cooperate. * Note: Height (significant swell height) is the average height of the waves in the top third of the wave record. Maximum wave heights 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 0.12 inches Wednesday 1500 through Thursday 1500 0.00 inches Precipitation this rain season (July 1 - June 30): 16.62 inches Average season rainfall at DCPP to date: 19.00 inches Ocean Lab Barometer: 30.15 in or 1021.1 mb +0.0 mb (Steady) Sunrise and Sunset Today's Sunrise 6:18 AM Sunset 6:08 PM Tomorrow's Sunrise 6:16 AM Sunset 6:09 PM Tides: Low Tide High Tide AM PM AM PM 12 Friday 1:46 1.9 2:30 0.0 7:41 5.0 8:54 4.1 13 Saturday 2:21 1.6 2:55 0.1 8:18 4.9 9:13 4.3 14 Sunday 3:54 1.3 4:18 0.3 9:53 4.8 10:33 4.6 15 Monday 4:28 1.0 4:40 0.6 10:28 4.7 10:54 4.8 16 Tuesday 5:03 0.8 5:03 0.9 11:05 4.4 11:16 4.9 17 Wednesday 5:41 0.6 5:27 1.2 11:45 4.1 11:41 5.0 18 Thursday 6:22 0.4 5:50 1.6 ----- --- 12:30 3.8 19 Friday 7:08 0.4 6:15 2.0 12:09 5.1 1:23 3.4 20 Saturday 8:04 0.4 6:44 2.3 12:42 5.1 2:34 3.0 21 Sunday 9:13 0.3 7:22 2.6 1:24 5.1 4:17 2.9 22 Monday 10:31 0.2 8:42 2.9 2:20 5.0 6:11 3.0 23 Tuesday 11:44 -0.1 10:46 2.9 3:36 4.9 7:11 3.3 ========================================================================= This day in weather history 1888 - A blizzard paralyzed southeastern New York State and western New England. The storm produced 58 inches of snow at Saratoga NY, and 50 inches at Middletown CT. The blizzard was followed by record cold temperatures, and the cold and snow claimed 400 lives. New York City received 20.9 inches of snow, Albany NY reported 46.7 inches. (David Ludlum) 1967 - A tremendous four day storm raged across California. Winds of 90 mph closed mountain passes, heavy rains flooded the lowlands, and in sixty hours Squaw Valley CA was buried under 96 inches (eight feet) of snow. ========================================================================= 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. Replication of this email must be in its entirety. 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