Marine Weather Net

Santa Cruz Island to San Clemente Island CA between 60 and 150 NM Offshore Forecast


TONIGHT

NNW
WINDS
20 - 30
KNOTS

THU

NNW
WINDS
15 - 25
KNOTS

THU NIGHT

NNE
WINDS
15 - 25
KNOTS

FRI

NE
WINDS
15 - 25
KNOTS

The Marine Weather Forecast In Detail:
PZZ840 Forecast Issued: 147 PM PST Wed Nov 25 2020

Tonight...N To Nw Winds 20 To 30 Kt. Seas 10 To 17 Ft.
Thu...N To Nw Winds 15 To 25 Kt. Seas 10 To 17 Ft.
Thu Night...N To Ne Winds 15 To 25 Kt. Seas 9 To 15 Ft.
Fri...Ne Winds 15 To 25 Kt, Diminishing To 5 To 15 Kt. Seas 6 To 11 Ft.
Fri Night...N Winds 5 To 15 Kt. Seas 5 To 9 Ft.
Sat...N Winds 5 To 15 Kt. Seas 4 To 7 Ft.
Sat Night...N To Nw Winds 5 To 10 Kt. Seas 4 To 7 Ft.
Sun...Nw Winds 10 To 15 Kt. Seas 4 To 7 Ft.
Sun Night And Mon...Nw Winds 10 To 20 Kt. Seas 4 To 8 Ft.
Mon Night...N To Nw Winds 15 To 25 Kt. Seas 6 To 10 Ft.
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138 PM PST Wed Nov 25 2020
Synopsis for the far southern California coast - PZZ700
At 2 PM a 1027 mb high was near Eureka and a 1016 mb low was near Needles. Santa Ana winds will bring gusty north to northeast winds to portions of the coastal waters Thursday night through Friday.
Area Forecast Discussion
National Weather Service San Diego CA
200pm PST Wednesday Nov 25 2020

Synopsis
Areas of low clouds will form over the coastal areas this evening and spread into the valleys tonight ahead of a trough of low pressure moving across the Great Basin. After the trough passes, gusty Santa Ana winds will move into Southern California Thursday and Friday. Skies will be mostly clear over the weekend with warm days, cool nigheights and low humidity.

FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Skies were generally clear this afternoon. Pressure gradients were trending onshore this afternoon ahead of a trough over the Pacific Northwest that will move across the Great Basin Thursday. Marine layer clouds will reform over the coastal waters this evening and push into the coastal zones and western valleys overnight.

Skies will clear in the Inland Empire early Thursday morning as the dry northerly flow kicks behind the passage of the trough axis. Skies will clear more slowly in San Diego County as the dry offshore will be slower to reach that area.

The pending Santa Ana winds event will be moderate in strength with the strongest winds Thursday into Friday morning. Northerly winds will surface in the San Bernardino County mountains late tonight, then move down the slopes into the Inland Empire and the Santa Ana mountains through midday. Strongest winds arrive late Thursday afternoon and continue through early Friday morning in these areas. The ECMWF (European Centre for Medium-Range Weather Forecasts) ensemble projects 60 mph wind gusts at Fremont Canyon in the foothills of the Santa Ana Mountains. Projected gusts at Ontario is 32 mph with the NBM.

The winds arrive later in San Diego County in this northerly flow event, reaching the San Diego County mountains and foothills Thursday evening through Friday morning. The winds will not be as strong as they will be farther north, with wind gusts from 40 to 50 mph in the mountains and foothills Friday morning. While the winds will not be as strong, the ensembles show moderate strength easterly winds persisting longer in San Diego County, continuing into Saturday.

Temperatures: Northerly flow will draw in a cool High Desert airmass into SoCal Thursday, so Thanksgiving will be a cool day in most areas. The coldest areas will be the High Deserts (highs in the mid 50s) and the San Bernardino Mountains (highs 35-45). The warmest areas will be inland Orange County where the offshore flow will push highs into the low 70s. The Lower Deserts will also see highs in the low 70s. Friday will be a warmer day in all areas, with the most significant warming west of the mountains from the Santa Ana downslope flow. Both Saturday and Sunday will be sunny and warmer.

Long Range Outlook for next week: There are differences in the operational GFS and the ECMWF runs, which isn't unusual, so we have sided with the ECMWF ensemble that project general ridging over the Southwest. On Monday a shortwave moves across the Pacific Northwest and then across the Great Basin Tuesday and Wednesday, with a high amplitude ridge over the West Coast. This pattern suggests above average chances of continued offshore flow over the Southwest through the middle of next week.

Marine
Gusty northeast winds will develop through Thu afternoon, with the highest winds Thu night through Fri morning. Expect winds in excess of 20 kts at times. Winds will diminish below 20 kts Fri afternoon, but breezy conditions will persist at times through Fri night.

Fire Weather
The Fire Weather Watch was upgraded to a Red Flag Warning today. The Red Flag Warning was shortened by a few hours due to the drop off in winds earlier than previously thought. The RFW is in effect from 2 PM Thursday to 6pm Friday for Orange, San Bernardino and Riverside Counties. In San Diego County the RFW is in effect from 9pm Thursday to 9am Saturday.

Northerly winds will surface in the San Bernardino County mountains tonight and then spread downslope into the Inland Empire and into the Santa Ana mountains Thursday. The strongest winds will arrive Thursday evening through Friday morning with gusts to 60 mph. This will be the period of greatest concern for rapid fire spread of any fires that do start. Weaker winds are forecast Saturday.

In San Diego County the northerly flow pattern will delay the onset of the winds until late Thursday afternoon or evening, with a period of gusty northeast winds Thursday night into Friday with gusts from 40-50 mph. Another round of slightly weaker winds follows on Saturday.

Lowest humidity on Thursday afternoon will fall to 10-20% for Orange, western Riverside, and southwestern San Bernardino Counties, followed by lower RH of 8-12% Friday. This drier air will spread south into San Diego County Thursday night and Friday.

Weaker winds may continue into Sunday and Monday. Little recovery in humidity for inland areas is expected on Sunday. On Monday, a recovery in humidity near the coast could begin to spread inland for Monday and Tuesday.

.SKYWARN... Skywarn activation will not be needed Thursday.

.SGX WATCHES/WARNINGS/ADVISORIES... CA...Red Flag Warning from 9pm Thursday to 9am PST Saturday for San Diego County Inland Valleys-San Diego County Mountains- Including The Palomar And Descanso Ranger Districts of the Cleveland National Forest.

Red Flag Warning from 2pm Thursday to 6pm PST Friday 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 Gorgonio Pass Near Banning-Santa Ana Mountains- Including The Trabuco Ranger District of the Cleveland National Forest.

PZ...NONE.