Marine Weather and Tide Forecast for Lake Forest, CA

DISCUSSION
FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

Key Messages:

- Moderate to strong and potentially damaging Santa Ana winds continuing through Tuesday afternoon.

- There is an 80 percent chance of a moderate strength Santa Ana event Wednesday night and Thursday.

- There is a 30-60 percent chance of measurable precipitation next Saturday and Sunday and a 60-80 percent chance of snow levels falling below 4000 ft Sunday morning, increasing to 80-90 percent Monday morning.

Evening update...
Moderate to strong Santa Ana winds are ongoing this evening. As of 830 PM, Banning hit a peak gust of 83 mph, Sill Hill (San Diego County Mountains) 77 mph, Keen Ridge (Riverside County Mountains)
75 mph, and Chino Hills (Santa Ana Mountains) 71 mph. Still expecting winds to continue to increase tonight, gradually shifting to more of an easterly direction and favoring the San Gorgonio Pass and San Diego County Mountains and adjacent foothills/valleys by Tuesday morning while beginning to weaken elsewhere. Winds for all locations will weaken through the afternoon Tuesday. The High Wind Warning for the Riverside County and San Diego County Mountains and the San Diego County Valleys was moved up to start at 9 PM as winds have already ramped up in these areas. The High Wind Warnings for all areas now end at 4 PM Tuesday, earlier than their initial end time of 8 PM as winds now look to weaken faster.

Otherwise cold tonight in the mountains and high deserts where temperatures will fall into the 20s, locally into the teens for the higher mountain valleys, including the Big Bear area.
Elsewhere min temperatures will vary greatly, falling into the low 30s in the colder wind sheltered valleys, but generally upper 30s to mid 40s elsewhere. The long wave trough covering much of the US will shift eastward by Wednesday, allowing upper level ridging to move in from the west, providing warmer days through Friday with highs 5-10 degrees above normal.

Previous discussion...
Surface pressure gradients restrengthen by late Wednesday into Thursday, which will provide another round of moderate Santa Ana winds. This event will be weaker and more confined to the usual wind prone areas. Confidence is lower on how strong winds will be in adjacent valleys, but the winds look to have a greater easterly component, which would favor passes/canyons in Riverside and San Diego Counties. ECMWF ensembles give Romona peak wind gusts near 40 MPH, though some members have gusts closer to 50 MPH. As the Santa Ana winds move over the area, temperatures may warm a bit more by Thursday over the western valleys. NBM probabilities paint a picture of around a 50-50 chance of seeing highs over 80 degrees from El Cajon to Anaheim to Temecula.

Another deep trough will push into the West by Friday into the weekend. Models are starting to become in better agreement of an area of low pressure cutting off from the mean the flow and moving over our region by the weekend. If this system stays far enough west, we will see an increased chance of precipitation. Models and ensembles continue to be wet with measurable precipitation, but how much is still in question. This system also looks to be a colder one, so snow levels below 4,000 feet may occur as well. Latest ensemble clusters are in fairly good agreement of the low sticking into the area by next Monday, a bit less so by Tuesday. The low may stick around even into next Monday, so chances for precip rain in the forecast for this weekend into early next week.

AVIATION
210430Z....Mostly clear skies through Tuesday evening. Strong east/northeasterly wind gusts 30-40 kts continue this evening, especially in the foothills, mountains, and mountain passes. A few corridors in the western valleys and into coastal Orange County are seeing gusts 20-30 kts. Very strong up/downdrafts remain possible near the mountains along with localized areas of blowing dust that could lead to VIS reductions. Gusts decrease in the coasts/valleys some by 09-12z but stay elevated in the mountains and foothills.
Winds re-intensify after 12z, largely in the mountains and foothills where gusts 40-55 kts expected, with local gusts near 60 kts. Gusts begin to gradually decrease after 21z Tuesday.

NWS San Diego is aware of limited communications of observations from KTRM since January 8th. We are working with the FAA to address this issue.

MARINE
Increasing offshore winds this evening, with gusts up to 25-30 kts and associated choppy seas, mostly north of La Jolla through San Clemente Island. Winds and seas will peak overnight, before gradually diminishing Tuesday morning. A Small Craft Advisory remains in effect and contains more details. No additional hazardous marine conditions are expected Tuesday afternoon through Friday.

FIRE WEATHER
Moderate to strong Santa Ana winds will continue into Tuesday afternoon, peaking in intensity tonight into Tuesday morning.
Widespread wind gusts of 35-55 mph will occur across the coastal slopes of the mountains and into the adjacent valleys, with local gusts over 75 mph in the favored passes, canyons, and coastal slopes. Winds will gradual shift to easterly tonight, favoring the San Diego and Riverside County mountains and adjacent foothills Tuesday morning. Relative humidity of 10-15% this evening will see little to no improvement overnight. Extremely dry weather is expected on Tuesday and Tuesday night with minimum humidity of 5-8% Tuesday afternoon, potentially remaining in the single digits in the mountains and foothills into Tuesday night with poor recovery elsewhere. A period of extreme fire weather conditions is likely across the coastal slopes, foothills, and adjacent valleys in San Diego County Tuesday morning due to the combination of wind gusts in excess of 50 mph and single digit relative humidity.

Winds will gradually weaken Tuesday evening with weak offshore flow and dry conditions continuing into Wednesday along the foothills and passes.

Winds strengthen again Wednesday night into Thursday when there is an 80 percent chance of a moderate Santa Ana event. These winds will possibly continue into Friday, though weaker. Relative Humidity will remain in the single digits to mid teens, maintaining critical fire weather conditions Wednesday evening into Thursday, and elevated to near critical conditions on Friday.
A Fire Weather Watch remains in place for 6 PM Wednesday through 6 PM Thursday. Conditions improve greatly Saturday and Sunday with the return of onshore flow and a 30-60 percent chance of rain and mountain snow.

SKYWARN
Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.



SGX WATCHES/WARNINGS/ADVISORIES
CA...Red Flag Warning until 10 PM PST Tuesday for Orange County Inland Areas-Riverside County Mountains-Including The San Jacinto Ranger District Of The San Bernardino National Forest-San Bernardino County Mountains-Including The Mountain Top And Front Country Ranger Districts Of The San Bernardino National Forest-San Bernardino and Riverside County Valleys -The Inland Empire-San Diego County Inland Valleys-San Diego County Mountains-Including The Palomar And Descanso Ranger Districts of the Cleveland National Forest-San Gorgonio Pass Near Banning-Santa Ana Mountains- Including The Trabuco Ranger District of the Cleveland National Forest.

High Wind Warning until 4 PM PST Tuesday for San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Gorgonio Pass Near Banning- Santa Ana Mountains and Foothills.

High Wind Warning until 4 PM PST Tuesday for Riverside County Mountains-San Diego County Mountains-San Diego County Valleys.

Fire Weather Watch from Wednesday evening through Thursday afternoon for Riverside County Mountains-Including The San Jacinto Ranger District Of The San Bernardino National Forest-San Bernardino County Mountains-Including The Mountain Top And Front Country Ranger Districts Of The San Bernardino National Forest-San Diego County Inland Valleys- San Diego County Mountains-Including The Palomar And Descanso Ranger Districts of the Cleveland National Forest- San Gorgonio Pass Near Banning-Santa Ana Mountains- Including The Trabuco Ranger District of the Cleveland National Forest.

PZ...Small Craft Advisory until 10 AM PST Tuesday for Coastal Waters from San Mateo Point to the Mexican Border and out to 30 nm- Waters from San Mateo Point to the Mexican Border Extending 30 to 60 nm out including San Clemente Island.