======== PG&E DCPP Weather Forecast for Tuesday 03/09/10 ============ SEA/SWELL: A series of storms will move into the Gulf of Alaska and combined with increasing northwesterly winds along the California coastline will continue to produce rough oceanographic conditions through this week. Today's 10- to 12-foot northwesterly (310-degree deep-water) sea/swell (with a 5- to 13-second period) will continue at this level through tonight. This northwesterly (310-degree deep-water) sea/swell will decrease to 7- to 9-feet on Wednesday morning (with a 7- to 17-second period), but then will build to 9- to 11-feet (with an 11- to 14- second period) on Wednesday afternoon through Thursday. A 5- to 7-foot northwesterly (295-degree deep-water) swell (with a 14- to 16-second period) will develop along our coastline on Friday. Another round of northwesterly winds will generate 8- to 10- foot northwesterly sea/swell over the weekend, decreasing on Monday to 5- to 7-feet (with an 11-to 13-second period). A 970 millibar storm is forecast to develop in the Gulf of Alaska on Friday. An 8- to 10-foot west-northwesterly (295-degree deep-water) swell (with a 16- to 18-second period) will arrive our coastline on next Tuesday, increasing to 10- to 12-feet by next Wednesday. Preliminary Analysis long-range forecast: Another high west-northwesterly swell could arrive our coastline on March 19. ATMOSPHERIC CONDITION: An upper-level low passed to the north of San Luis Obispo late last night and produce a few scattered rain showers. Rainfall amounts ranged from just a trace in most locations to a few hundreds of a inch. A very steep pressure gradient and sparkling clear visibilities have developed in its wake this morning. Northwesterly winds will reach strong to gale force (25-38 mph) levels with gust to 50 mph along our coastline this afternoon through tonight. Temperatures today will be colder and mostly in the middle to upper 50s, but the winds will make it feel much colder. Another fast moving cold front will produce increasing clouds this evening through tonight with some light rain showers developing early Wednesday morning. Amounts will be less than a tenth of a inch. Snow levels will be quite low with snow expected near 2,500 and 3,000 feet. Clearing and strong to gale force (25-38 mph) northwesterly winds is expected late Wednesday morning through the evening hours. The winds will decrease Wednesday night. A clear, calm and cold night is forecasted on Wednesday night into Thursday morning with temperatures dipping down into high 20s in the interior to the mid to high 30s the coastal valleys. These temperatures are quite cold for the middle of March and frost is likely in the interior valleys and maybe even a few of our coastal valleys. Another cold front should pass our area late Friday night into Saturday morning with rain. Rain amounts look to be heavier with this system with about half an inch. Snow levels will be higher at 5,500 feet . Fair and windy weather is forecast on Saturday afternoon into Tuesday. Temperatures will also warm nicely on Sunday and next Monday with maximums reaching into the 70s. DIABLO CANYON AIR TEMPERATURES: Diablo Canyon Meteorological Tower Air Temperature Data Yesterday's Today's Tomorrow's Min Max Min Max Min Max 50.2° 56.7° 46.8° 57.0° 48.0° 58.0° PG&E San Francisco Met Office predicted temps: Inland Temperatures, Paso Robles Tue Wed Thu Fri Sat Sun Mon Tue 34 55 36 55 28 64 32 68 38 65 38 67 37 71 40 71 Coastal Valleys Temperatures, San Luis Obispo Tue Wed Thu Fri Sat Sun Mon Tue 36 59 42 55 39 67 37 65 43 64 45 67 44 70 45 70 WINDS: Strong to gale force (25-38 mph) northwesterly winds with gust to 50 mph along the coastline will develop this afternoon through tonight. The winds will shift out of the north to northeast (offshore) on Wednesday morning, then build to strong to gale force (25-38 mph) level by Wednesday afternoon. The winds will decrease Wednesday night into Thursday morning. The northwesterly winds will decrease to fresh to strong (19-31 mph) levels on Thursday, becoming light and variable on Friday. Another round of increasing northwesterly winds is forecast over the weekend. Today's winds: Max peak winds: N 31.7 mph at 7:45 a.m. Max sustained wind: N 14.8 mph at 7:45 a.m. Yesterday's Winds: Max peak winds: NW 43.2 mph at 7:00 p.m. Max sustained wind: NW 35.1 mph at 7:00 p.m. SEAWATER TEMPERATURES: The Diablo Canyon waverider buoy is reporting a sea surface temperature of 53.6 degrees while the Nortek AWAC current meter is reporting 51.3 degrees. Intake seawater temperatures will range between 50° and 53° through Thursday, increasing on Friday. OCEAN CURRENTS: The DCPP Cal Poly CODAR stations and the DCPP Nortek AWAC meter are indicating a southerly (offshore) flowing current this morning. This southerly (offshore) flowing current will continue to flow southward through Thursday. SEAWATER VISIBILITY: Seawater visibility was 3 to 5 feet at the Diablo Canyon Intake. ========================================================================== 24-Hour Ocean Condition Outlook for Tuesday 03/09 to Wednesday 03/10 Sea/Swell: DIR. NW HT. 10-12 PER. 5-14 This morning Remaining at: DIR. NW HT. 10-12 PER. 7-13 This afternoon Remaining at: DIR. NW HT. 10-12 PER. 7-13 Tonight WINDS: DIR. NNW SPEED 20-25 + 30 This morning Increasing To: DIR. NW SPEED 35-40 + 50 This afternoon Decreasing to: DIR. NW SPEED 25-30 + 40 Tonight =========================================================================== 48-Hour Ocean Condition Outlook for Wednesday 03/10 to Thursday 03/11 Sea/Swell: DIR. NW HT. 7-9 PER. 7-17 Wednesday morning Increasing to: DIR. NW HT. 9-11 PER. 7-16 Wednesday afternoon Remaining at: DIR. NW HT. 9-11 PER. 7-15 Wednesday night WINDS: DIR. NE SPEED 20-25 + 30 Wednesday morning Increasing To: DIR. NW SPEED 30-35 + 45 Wednesday afternoon Decreasing to: DIR. NW SPEED 15-25 + 35 Wednesday night =========================================================================== Extended Ocean Condition Outlook: The northwesterly winds will decrease to fresh to strong (19-31 mph) levels on Thursday, becoming light and variable on Friday. ========================================================================== 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 (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 Daily Swell Inspection Program NAME DAY TIME HEIGHT PERIOD SST (PST) (FEET) (SECONDS) (DEG. F) # 75 Shumagin Islands, AK 9 0520 16 11 39.9 # 66 South Aleutians 9 0550 17 9 37.9 # 06 SE PAPA 600NM West Eureka (No current data today) # 59 California Buoy (No current data today) # 01 Point Reyes Waverider 9 0501 17 13 52.0 # 42 Monterey Waverider Buoy 9 0506 10 11 55.2 # 28 Cape San Martin, Ca 9 0550 17 11 55.9 # 50 DCPP Waverider Buoy, Ca 9 0513 12 11 53.6 # 71 Harvest Platform, Ca 9 0530 17 12 55.4 # 01 NW Hawaii 9 0550 9 8 70.3 * 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. Sunday 1500 through Monday 1500 0.00 inches Monday 1500 through Tuesday 1500 0.00 inches Precipitation this rain season (July 1 - June 30): 16.50 inches Average season rainfall at DCPP to date: 18.50 inches Ocean Lab Barometer: 30.13 in or 1020.4 mb +1.0 mb (Rising) Sunrise and Sunset Today's Sunrise 6:22 AM Sunset 6:05 PM Tomorrow's Sunrise 6:20 AM Sunset 6:06 PM Tides: Low Tide High Tide AM PM AM PM 9 Tuesday ----- --- 12:47 0.1 5:12 4.7 7:45 3.7 10 Wednesday 12:20 2.6 1:28 0.0 6:12 4.8 8:12 3.8 11 Thursday 1:07 2.3 2:02 0.0 7:00 4.9 8:34 4.0 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 ========================================================================= This day in weather history 1956 - A whopping 367 inches of snow was measured on the ground at the Ranier Paradise Ranger Station in Washington. The snow depth was a state record and the second highest total of record for the continental U.S. ========================================================================= 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. You may view and copy material from this forecast, provided you retain all copyright, trademark, and other proprietary notices displayed on the materials. Use of these materials in publications, radio, television, other media presentations, or other websites is prohibited without PG&E's express written consent. 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