• This week's San Luis Obispo Tribune's Weather Watch Column "It’s April, but SLO County could still see decent rain and frost" www.sanluisobispo.com/news/weather/weather-watch • You can catch live weather forecasts weekday mornings from 6-9 a.m. on KVEC 920 AM on First Look with Andy Morris • For weather updates, charts and photos, along with power outage information and other events you can follow me at: https://twitter.com/pge_john ======== PG&E DCPP Weather Forecast for Thursday 04/09/20 ======== SEA/SWELL: Today's 4- to 6-foot northwesterly (310-degree, deep- water) swell (with an 8- to 14-second period) will remain at this level through tonight. A 3- to 5-foot northwesterly (310-degree, deep-water) swell (with an 8- to 11-second period) is expected along our coastline on Friday through Tuesday. Increasing northwesterly sea and swell is forecast next Wednesday and Thursday. Arriving from the Southern Hemisphere: Today's 2- to 3-foot Southern Hemisphere (190-degree, deep-water) swell (with a 14- to 16-second period) will remain at this level through Friday. ATMOSPHERIC CONDITIONS: The 550 dm upper-level low-pressure system, responsible for all this month's rain, is moving eastward. It will continue to produce moderate to fresh (13 to 24 mph) southerly winds and rain throughout San Luis Obispo and Santa Barbara counties this morning, tapering off this afternoon. Total rainfall amounts today will range between 0.33 and 0.75 of an inch. Today's high temperatures will range between the high 50s to the low 60s throughout the Central Coast with snow levels at around 5,000 feet. In this system's wake, high pressure will build in behind it and will produce gusty Santa Lucia (northeasterly) winds on Friday morning. These offshore winds will create clear skies in the coastal regions but extensive stratus clouds and dense fog in the inland areas, especially along the Santa Lucia mountain range. By Friday afternoon and through most of next week, mostly clear skies and warmer temperatures will develop. However, dense overnight valley fog and marine low clouds will develop along the coastline over this period. WILDFIRE INDEX RATINGS: The PG&E Fire Index Ratings will be at low (R1) levels along the Coastline, Coastal and Inland Valleys and Far Inland Areas today, Friday and Saturday. DIABLO CANYON METEOROLOGICAL TOWER TEMPERATURE DATA: Yesterday's Today's Tomorrow's Min Max Min Max Min Max 48.6° 53.7° 48.3° 57.0° 52.0° 64.0° PG&E Weather Office in San Francisco predicted temperatures for San Luis Obispo County Inland Temperatures, Paso Robles Actual Predicted Wed Thu Fri Sat Sun Mon Tue Wed Thu 47 56 48 57 42 69 44 73 45 70 46 72 48 78 46 77 47 72 Coastal Valleys Temperatures, San Luis Obispo Wed Thu Fri Sat Sun Mon Tue Wed Thu 46 56 48 58 47 68 47 67 49 63 49 65 47 70 48 67 49 66 WINDS: Moderate to fresh (13 to 24 mph) southerly winds are forecast through today. Moderate to fresh (13 to 24 mph) Santa Lucia (northeasterly) winds are forecast on Friday morning. A pattern of fresh to strong (19 to 31 mph) northwesterly winds developing during the afternoon, decreasing during the night and morning will start Friday afternoon and will continue through Tuesday. DIABLO CANYON METEOROLOGICAL TOWER WIND DATA: Today's Maximum Winds: Max peak winds: SE 27.0 mph @ 3:45 a.m. Max sustained wind: SE 21.0 mph @ 3:45 a.m. Yesterday's Maximum Winds: Max peak winds: SE 16.0 mph @ 12:30 p.m. Max sustained wind: SE 13.0 mph @ 12:30 p.m. SEAWATER TEMPERATURES: Intake seawater temperatures will range from 54 and 56 degrees through today, decreasing on Friday through Tuesday. OCEAN CURRENTS: A northerly (onshore) flowing current is forecast to flow northward through today. A southerly (offshore) flowing current is forecast to flow southward on Friday through Monday. SEAWATER VISIBILITY: Seawater visibility was 3 to 5 feet at the Diablo Canyon Marina. ========================================================================== 24-Hour Ocean Condition Outlook for Thursday 04/09 to Friday 04/10 SWELL: DIR. NW HT. 4-6 PER. 8-15 This morning Remaining at: DIR. NW HT. 4-6 PER. 8-14 This afternoon Remaining at: DIR. NW HT. 4-6 PER. 8-13 Tonight (Combined with: DIR. S HT. 2-3 PER. 14-16 All day) WINDS: DIR. SE SPEED 15-20 + 25 This morning Remaining at: DIR. SE SPEED 15-20 + 25 This afternoon Decreasing to: DIR. SW SPEED 10-15 Tonight ========================================================================== 48-Hour Ocean Condition Outlook for Friday 04/10 to Saturday 04/11 SWELL: DIR. NW HT. 4-6 PER. 8-12 Friday morning Remaining at: DIR. NW HT. 4-6 PER. 8-11 Friday afternoon Remaining at: DIR. NW HT. 4-6 PER. 8-11 Friday night (Combined with: DIR. S HT. 2-3 PER. 14-16 All day Friday) WINDS: DIR. NE SPEED 15-20 + 25 Friday morning Increasing to: DIR. NW SPEED 20-25 + 30 Friday afternoon Decreasing to: DIR. NW SPEED 10-15 Friday night ========================================================================== Extended Ocean Condition Outlook: Dry and warmer weather is favored in the wake of this upper-level low-pressure system on Friday, Saturday and Sunday. ========================================================================== The 24 - Hour Ocean Data from the Diablo Canyon Waverider Buoy: MONTH DAY TIME SIG.HEIGHT PERIOD SWELL DIRECTION SST 04 02 0633 6.5 11 288 51.4 04 03 2233 6.9 10 282 50.7 04 04 0933 5.1 7 288 51.1 04 05 1333 7.2 6 210 52.5 04 06 1433 5.6 9 278 56.5 04 07 1403 4.7 20 250 57.4 04 08 2103 5.1 17 231 54.3 04 09 0503 5.1 15 241 53.6 DCPP Ocean Lab Waverider Buoy Energy Spectral Analysis: Mo. daytime sig.ht. sig.per. energy (cm.sq.) (cm) (sec) 22+ 20 17 15 13 11 9 7 -------------------------------------------------------------------------- 04 02 0633 197 7 2 13 104 61 77 358 579 732 04 03 0603 183 7 1 7 73 86 60 124 468 753 04 03 2233 209 7 2 4 34 133 72 179 654 896 04 04 0933 154 7 1 3 9 52 82 35 146 568 04 05 1333 218 4 1 4 11 25 80 74 51 1802 04 06 1433 170 9 3 7 18 56 28 145 675 459 04 07 1403 142 11 23 214 15 33 58 309 273 166 04 08 2103 156 17 4 35 401 320 32 58 248 224 04 09 0503 155 15 3 29 198 340 39 67 230 339 Daily Swell Inspection Program for today: NAME DAY TIME HEIGHT PERIOD SST (PST) (FEET) (SECONDS) (DEG. F) # 66 Ocean Station Papa 9 0533 11 10 44.8 # 06 SE Papa The buoy at this station has gone adrift. # 05 West Washington State 9 0540 4 13 n/a # 59 California 9 0550 10 9 n/a # 44 Humboldt Bay Waverider 9 0533 9 9 51.8 # 94 Cape Mendocino 9 0532 9 8 51.4 # 29 Point Reyes Waverider 9 0503 7 15 53.4 # 42 San Francisco Sandbar 9 0530 5 17 54.7 # 15 Monterey Waverider Buoy no data today # 28 Cape San Martin 9 0550 6 16 56.1 # 76 DCPP Waverider 9 0503 5 15 53.6 # 22 Santa Lucia Escarpment 9 0533 7 15 57.0 # 11 Point Arguello 9 0550 6 16 54.5 # 63 Harvest Buoy 9 0550 7 17 56.3 # 19 San Nicolas Island 9 0533 7 17 57.9 # 20 Scripps 9 0522 2 17 60.4 # 10 Waimea Bay, Hawaii 9 0500 6 10 76.8 # 33 Pearl Harbor Entrance 9 0500 2 13 76.8 # 04 SE Hawaii 9 0500 6 13 76.5 Precipitation at the Diablo Canyon Ocean Lab: Friday 1500 through Saturday 1500 0.00 inches Saturday 1500 through Sunday 1500 0.43 inches Sunday 1500 through Monday 1500 0.57 inches Monday 1500 through Tuesday 1500 0.00 inches Tuesday 1500 through Wednesday 1500 0.25 inches Wednesday 1500 through Thursday 0700 0.25 inches Precipitation this rain season (July 1 - June 30): 14.10 inches Average season rainfall at DCPP to date: 17.25 inches Ocean Lab Barometer: 1017.3 mb or 30.04 in/Hg -1.0 mb (lowering) Today's Sunrise 6:38 AM Sunset 7:31 PM Tomorrow's Sunrise 6:36 AM Sunset 7:32 PM Tides: Low Tide High Tide AM PM AM PM 9 Thursday 5:47 -0.7 5:37 0.9 12:02 4.5 11:50 5.9 10 Friday 6:42 -0.8 6:17 1.5 ----- --- 1:05 4.1 11 Saturday 7:41 -0.7 7:02 2.1 12:31 5.8 2:18 3.7 12 Sunday 8:46 -0.6 7:59 2.6 1:17 5.5 3:46 3.4 13 Monday 9:59 -0.4 9:24 2.9 2:12 5.1 5:25 3.5 14 Tuesday 11:14 -0.2 11:11 2.9 3:21 4.7 6:44 3.7 15 Wednesday ----- --- 12:21 -0.2 4:44 4.4 7:36 3.9 16 Thursday 12:37 2.6 1:16 -0.1 6:04 4.3 8:13 4.1 17 Friday 1:37 2.1 2:00 0.0 7:09 4.3 8:42 4.3 18 Saturday 2:22 1.7 2:35 0.1 8:02 4.3 9:07 4.4 19 Sunday 2:59 1.3 3:05 0.4 8:47 4.3 9:28 4.6 20 Monday 3:33 0.9 3:32 0.6 9:27 4.2 9:49 4.7 21 Tuesday 4:06 0.6 3:56 0.9 10:06 4.1 10:09 4.9 ======================================================================== This day in weather history 1989 - Unseasonably hot weather prevailed in California. Afternoon highs of 91 degrees in Downtown San Francisco, 93 degrees at San Jose, 98 degrees at San Diego, 103 degrees at Santa Maria, 104 degrees at Riverside, and 106 degrees in Downtown Los Angeles established records for the month of April. 2016 - Yesterday's high temperatures reached 89 degrees in San Luis Obispo, 88 in Paso Robles and 91 at Santa Marina. These air temperatures were near record levels. 2018 - Saturday's weather system produced around a third of an inch of rain in most Central Coast locations. However, Dawn at the Walter Ranch received seven tenths of an inch of rain. The best word to describe this week’s upcoming weather would be windy. ======================================================================== 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. PG&E is a subsidiary of PG&E Corporation, one of the largest natural gas and electric utilities in the United States, delivering some of the nation's cleanest energy to 15 million people in Northern and Central California. If you would like to subscribe or unsubscribe to this daily Forecast or any questions, please send an email to PGEweather@pge.com.