. This week's San Luis Obispo Tribune's Weather Watch Column "The Cold Moon will mark the shortest day of the year in SLO. Here’s the science behind it." http://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 12/13/18 =========== SEA/SWELL: Today's 8- to 10-foot northwesterly (310-degree, deep-water) swell (with an 11- to 16-second period) will decrease to 7 to 9 feet (with a 15- to 17-second period) on Friday. An 8- to 10-foot northwesterly (300-degree, deep-water) swell (with an 11- to 14-second period) is forecast along our coastline on Saturday into Sunday morning. A 955 millibar storm with hurricane-force westerly-winds in the Gulf of Alaska will produce a 7- to 9-foot west- northwesterly (285-degree, deep-water) swell (with an 22- to 24-second period) along our coastline on Sunday afternoon, peaking at 15 to 17 feet (19- to 21-second period) Monday. Combined with this west-northwesterly swell will be southerly seas on Sunday into Monday. This west-northwesterly swell will be followed by a 10- to 12-foot northwesterly (310-degree, deep-water) swell (with a 24- to 26-second period) on Tuesday, peaking at 9 to 11 feet (with an 18- to 21-second period) next Wednesday and Thursday. ATMOSPHERIC CONDITION: Today will be sunny with afternoon temperatures reaching the mid-60s in the North County and along the beaches, while the coastal valleys will hit the low 70s A weakening cold front will produce moderate to fresh (13 to 24 mph) southerly winds, increasing clouds and rain showers on Friday. Partly cloudy and dry weather is forecast on Saturday. A stronger cold front is forecast to move into the Central Coast later on Sunday into Monday morning with fresh to strong (19 to 31 mph) southerly winds, increasing clouds and widespread rain and mountain snow. Total rainfall amounts are forecast to range between 0.50 and 1.00 inches of rain. Fair and dry weather will returns to all areas on Tuesday into next Thursday, with the next chance of rain next Friday and Saturday. WILDFIRE DANGER RATINGS: Today's PG&E Fire Index Ratings are at medium levels along the coastline and in the coastal and inland valleys. Weather graphics and power outage information are available at: twitter.com/pge_john. Yesterday's Today's Tomorrow's Min Max Min Max Min Max 56.8° 65.5° 56.1° 64.9° 56.0° 60.0° 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 34 59 33 67 38 62 40 63 40 62 44 60 38 61 38 63 Coastal Valleys Temperatures, San Luis Obispo Wed Thu Fri Sat Sun Mon Tue Wed 44 67 42 72 45 65 44 66 43 66 48 64 45 67 45 70 WINDS: Gentle to moderate (8 to 18 mph) southerly winds are forecast into Friday morning, increasing to moderate to fresh (13 to 24 mph) levels on Friday afternoon and night. Gentle to moderate (8 to 18 mph) southerly winds are forecast on Saturday, increasing to fresh to strong (19 to 31 mph) levels on Sunday into Monday. Increasing southerly winds are forecast on Thursday afternoon into next Monday. DIABLO CANYON METEOROLOGICAL TOWER WIND DATA: Today's Maximum Winds: Max peak winds: NE 34.7 mph @ 0:30 a.m. Max sustained wind: NE 24.7 mph @ 0:30 a.m. Yesterday's Maximum Winds: Max peak winds: NE 46.3 mph @ 5:30 a.m. Max sustained wind: NE 30.2 mph @ 5:30 a.m. SEAWATER TEMPERATURES: Intake seawater temperatures will range between 56 and 60 degrees through tonight, increasing to 57 to 61 degrees on Friday into Monday. OCEAN CURRENTS: A southerly (offshore) flowing current is forecast to flow southward into tonight, becoming a northerly flowing current on Friday into Monday. SEAWATER VISIBILITY: Seawater visibility was 2 to 4 feet at the Diablo Canyon Marina. ========================================================================== 24-Hour Ocean Condition Outlook for Thursday 12/13 to Friday 12/14 SWELL DIR. NW HT. 7-9 PER. 11-17 This morning Increasing to: DIR. NW HT. 8-10 PER. 11-16 This afternoon Remaining at: DIR. NW HT. 8-10 PER. 11-15 Tonight WINDS: DIR. NE SPEED 20-25 + 40 This morning Decreasing to: DIR. SE SPEED 10-15 This afternoon Decreasing to: DIR. SE SPEED 5-10 Tonight ========================================================================== 48-Hour Ocean Condition Outlook for Friday 12/14 to Saturday 12/15 SWELL DIR. NW HT. 7-9 PER. 13-16 Friday morning Remaining at: DIR. NW HT. 7-9 PER. 15-17 Friday afternoon Decreasing to: DIR. NW HT. 6-8 PER. 15-17 Friday night WINDS: DIR. SE SPEED 5-10 Friday morning Increasing to: DIR. SE SPEED 15-20 + 25 Friday afternoon Decreasing to: DIR. SE SPEED 10-15 Friday night =========================================================================== Extended Ocean Condition Outlook: A 10- to 12-foot northwesterly (310-degree, deep-water) swell (with a 24- to 26-second period) will arrive along our coastline on Tuesday, peaking at 9 to 11 feet (with an 18- to 21-second period) next Wednesday and Thursday. =========================================================================== The 24 - Hour Ocean Data from the Diablo Canyon Waverider Buoy: MONTH DAY TIME SIG.HEIGHT PERIOD SWELL DIRECTION SST 12 05 0300 7.3 8 244 58.6 12 06 0700 4.5 22 262 59.4 12 06 2100 8.2 20 275 59.4 12 07 1000 7.0 18 258 59.2 12 08 1500 4.7 13 267 65.3 12 09 1130 4.4 13 269 61.9 12 10 1830 7.9 14 264 59.0 12 11 1600 7.8 12 274 61.9 12 12 0600 6.0 11 275 57.6 12 13 0730 8.7 13 275 60.3 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 -------------------------------------------------------------------------- 12 05 0300 222 7 1 1 3 20 27 85 882 858 12 06 0700 137 7 70 39 2 22 93 238 230 181 12 06 2100 249 20 150 2423 391 47 78 222 164 131 12 07 1000 212 17 29 1005 1072 154 76 127 144 92 12 08 1500 142 15 2 12 92 452 435 106 38 58 12 09 1130 136 13 0 2 14 104 519 240 135 45 12 10 1830 242 15 15 170 562 886 826 528 238 213 12 11 1600 237 11 2 9 28 417 595 835 622 385 12 12 0600 184 9 0 3 11 39 243 337 549 328 12 13 0730 266 13 9 127 72 732 1235 930 627 355 Daily Swell Inspection Program for today: NAME DAY TIME HEIGHT PERIOD SST (PST) (FEET) (SECONDS) (DEG. F) # 66 Ocean Station Papa 13 0703 21 14 46.8 # 36 South Nomad 13 0750 24 16 52.3 # 05 West Washington State 13 0750 20 14 n/a # 02 West Oregon 13 0725 15 16 57.4 # 06 SE Papa 13 0740 19 15 59.4 # 59 California 13 0750 14 16 61.0 # 44 Humboldt Bay Waverider 13 0703 13 14 56.1 # 29 Point Reyes Waverider 13 0723 13 13 58.8 # 42 San Francisco Sandbar 13 0725 9 14 56.1 # 15 Monterey Waverider Buoy 13 0700 11 13 58.1 # 28 Cape San Martin 13 0730 14 14 58.5 # 76 DCPP Waverider 13 0730 9 13 60.3 # 22 Santa Lucia Escarpment 13 0715 13 12 59.0 # 11 Point Arguello 13 0720 11 12 58.3 # 63 Harvest Buoy 13 0705 10 14 59.4 # 19 San Nicolas Island 13 0700 7 13 61.5 # 20 Scripps 13 0750 3 8 62.6 # 33 Pearl Harbor Entrance 13 0700 3 7 77.9 # 04 SE Hawaii 13 0700 12 9 78.3 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): 4.16 inches Average season rainfall at DCPP to date: 3.70 inches Ocean Lab Barometer: 30.22 in/Hg or 1023.2 mb +0.5 mb (Rising) Today's Sunrise 7:03 AM Sunset 4:52 PM Tomorrow's Sunrise 7:04 AM Sunset 4:52 PM Tides: Low Tide High Tide AM PM AM PM 13 Thursday 8:00 3.2 8:37 0.5 3:23 4.0 1:02 4.1 14 Friday 9:31 3.0 9:25 0.8 4:09 4.1 2:13 3.7 15 Saturday 10:51 2.6 10:11 1.1 4:47 4.4 3:38 3.5 16 Sunday 11:50 2.0 10:56 1.3 5:19 4.7 5:02 3.4 17 Monday (11:38 1.5) 12:37 1.4 5:49 5.0 6:15 3.4 18 Tuesday ---------- 1:19 0.7 6:19 5.4 7:18 3.5 19 Wednesday 12:20 1.7 1:59 0.0 6:51 5.8 8:13 3.7 20 Thursday 1:01 1.9 2:39 -0.6 7:26 6.2 9:04 3.8 21 Friday 1:43 2.1 3:21 -1.0 8:04 6.5 9:53 4.0 22 Saturday 2:27 2.2 4:04 -1.4 8:44 6.7 10:42 4.1 23 Sunday 3:14 2.3 4:50 -1.5 9:27 6.7 11:33 4.1 24 Monday 4:05 2.4 5:37 -1.4 10:14 6.6 ----- --- 25 Tuesday 5:02 2.5 6:27 -1.2 11:04 6.2 (12:26 4.2) 26 Wednesday 6:08 2.5 7:18 -0.8 11:59 5.7 (1:21 4.3) 27 Thursday 7:27 2.5 8:11 -0.3 2:17 4.5 1:04 5.0 28 Friday 8:57 2.3 9:06 0.3 3:14 4.7 2:21 4.3 ======================================================================== This day in weather history 1962 - A severe Florida freeze occurred. Morning lows reached 35 degrees at Miami, 18 degrees at Tampa, and 12 degrees at Jacksonville. It was the coldest December weather of the 20th century and caused millions of dollars damage to crops and foliage. In Georgia, the morning low of 9 degrees below zero at Blairsville established a state record for the month of December. (David Ludlum) 2002 - A powerful Pacific storm system plowed into the western United States during the 13th-16th, producing high winds, heavy rains, significant mountain snowfall. Rainfall amounts exceeding 10 inches occurred in parts of Northern California. The Diablo Canyon Ocean Lab reported 1.94 inches. 2018 - For the second day in a roll, the San Luis Obispo County Airport broke a high-temperature record by reaching 86 degrees Tuesday, beating the old record of 82° set back in 1958. Paso Robles hit 74° nearly matching the record high of 75° set back in 1988. Along the coastline, Diablo Canyon reached 82 degrees. ======================================================================== 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, please send an email to PGEweather@pge.com. Any questions about this forecast, please E-mail John Lindsey at jcl5@pge.com