Keeping SoCal updated
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Pattern Change
Aside from some precipitation during the beginning of the month and a cutoff low towards the end, January has largely been dry and warm (during the day at least) for SoCal. Numerous Santa Ana wind events and sunny skies have domineered our weather. After this prolonged period of dry weather, weather models have finally started hinting towards a pattern change some time towards the middle of the month.
00Z GFS @ HR156 showing the breakdown of the ever persistent ridge off the west coast.
12Z ECMWF @ HR168 showing a trough approaching the west coast
December was extraordinarily wet for Southern California with many locations exceeding their seasonal average rainfall. Therefore, even if not a single drop of rain fell through June (which is unlikely), we would be set to end this season above average. This is a year during which there is a strong La Nina, which makes this exceptionally rare, but only goes to prove that there were (are) many other factors at play which caused us to have so much precipitation.
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An Historic Day for SoCal
Today was one of the hottest days ever recorded in Southern California, rivaling that of 1963 when coastal areas such as Santa Monica reached 104F. Offshore gradients were stronger than forecast and temperatures soared to way above the original high temperatures for today. A few areas set or tied their all time record temperatures, such as Los Angeles, which reached an astonishing 113F! That was the highest temperature ever seen since record keeping began in 1877. An what makes it even more interesting, is that the temperature could have been even higher - the temperature sensor at the NWS Downtown location broke after reaching 113F and needed to be repaired which left some time of no data collection.
Today in the coastal areas, it felt more like a desert. There was no marine influence (aside from a little at the immediate beach, such as Santa Monica Pier, which only reached 83F). But if you literally went 5 blocks inland, the temperature soared to 97F. And from that a few blocks farther inland, into the low to mid 100s. Santa Monica Airport reached 103F today, almost tying the all time record temperature of 104F set back in September of 1963 (According to the weather channel, 106F was reached, which would have broken that). LAX tied the record high for the day of 105F and Hawthorne soared to 111F. A non NWS reporting stations recorded up to 119F, although these are unofficial readings, they are extremely impressive.
We have lived through history today. Luckily, what we had today was a dry heat and it was not as terrible as it could have been as humidities were extremely low. Nevertheless, it was a very impressive day temperature wise on ANY scale.
The upper high will start to move eastward tomorrow and a low pressure system will move north from Baja California. If anyone took a look at the sky this afternoon, you probably noticed a few flat cumulus clouds. This is because the low pressure to the SW and high pressure to the NE of us will start drawing in monsoonal moisture from Mexico. This could set up for a very interesting situation as moisture will not necessarily be confined to the mountain and desert areas.
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The Heat Returns
As we enter the first days of fall, summer-like weather has taken over the southland. A large area of high pressure is building in over the Southwestern United States and it will bring very hot temperatures to the entire area; even the coast will be warming up with no marine layer present. Light offshore flow across the region will also bring very low dew points to the area resulting in heightened fire concerns and a red flag warning.
Temperatures today are already running a good at least 10 degrees above average in all areas and this isn’t even the peak of the heatwave. The hottest temperatures are expected to be tomorrow through Tuesday when offshore flow strengthens a little. There is not very good support at the surface for strong winds, so most areas, aside from favorable canyons and passes, will see light breezes. Here are my forecast highest temps for the period:
Beaches: 75 - 79
Coastal Cities: 82 - 90
Inland Coastal Plain: 94 - 103
Valleys: 105 - 111
At this hour temperature are running in the low 80s to 90s across areas west of the mountains, with some areas in the Inland Empire approaching or exceeding 100.
A low pressure system which will move into northern Baja California could cause an influx of some monsoonal moisture or clouds later in the week, but so far most models have not been brining any precipitation. This feature will need to be watched closely though as it could bring some uncomfortable dew points to the area. This is still a tossup at this point and my might not happen.
In the Long-Range, temperatures should slowly begin to cool after Wednesday to around normal in most areas and mr marine layer could make a reappearance. Enjoy the weather folks, drink plenty of fluids and make sure to not leave kids or pets alone in the car for any period of time, even with the windows open.
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Cold Beaches!!!
The marine layer has been very shallow the past few days producing some very dense fog with visibilities less than a quarter of a mile in many coastal communities. One location that has been breaking records like crazy this past week is Santa Monica. Record lows have been broken or tied 6 out of the last 8 days. Here’s the preliminary data:
- Sep 12: 65 / 55
- Sep 13: 69 / 55 (Tied 1949)
- Sep 14: 72 / 54 (Tied 1961)
- Sep 15: 65 / 53 (55 - 1952) (0.01”)
- Sep 16: 66 / 54 (Tied 1952) (0.01”)
- Sep 17: 67 / 53 (Tied 1952)
- Sep 18: 65 / 55
- Sep 19: X / 51! (56 - 1948)
If you are looking for a place to cool off, look no further than the coastal communities. Thanks to a shallow and very strong marine inversions, temperatures have been running 5 - 10F below average almost the entire month with more of the same expected for at least the next few days.
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Temperatures today will be at least 10 degrees below average in most areas and 20 to 25 degrees below average in some inland valley and foothill locations
– NWS San Diego -
A Breath of Fall
[Marine Layer Clouds from Palomar Observatory - Scott Kardel]
Yesterday and this morning felt much more like it was a late fall day. Marine layer clouds made it far inland and didn’t clear out all day and some places even received measurable precipitation.
Temperatures yesterday were running WAY below normal with some inland areas not even reaching 70 degrees. Here are a few examples:
- Burbank: 68F (-20F from normal)
- Palmdale: 76F (-17F from normal)
- Sandberg: 61F (-20F from normal)
- Lancaster: 73F (-18F from normal)
- Ontario: 70F (-22F from normal!, T precipitation)
- Riverside: 72F (-20F from normal)
- Campo: 71F (-20F from normal)
A strong trough which deepened the marine layer to 4000+ feet around LA country and an amazing 6000 feet deep near San Diego is to thank for yesterdays expansive coverage of the clouds and unseasonably cold temperatures. A number of records were also set yesterday:
Lowest Max Temp
- Campo - 73F (78F - 1962), 75F (Tied 1972)
- El Cajon - 73F (78F - 2001)
- Laguna Beach - 69F (Tied 1962)
- Oceanside Harbor - 66F (Tied 1991), 66F (Tied 2001)
Lowest Minimum Temp
- Sandberg - 43F (44F - 1950)
- Borrego - 57F (59F - 1985)
The marine layer clouds are struggling to hang on today as 850mb temperatures have dropped to 7C! There are multiple inversions in the atmosphere, but all are far too weak to support and organized clouds. Most areas have cleared, or have begun clearing out. Temperatures today will be perhaps a little warmer than yesterday because of the added sunshine, but should overall remain much below normal.
Look for temperatures to warm up a bit to around normal, then slowly cool down again next week.
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Below Average Again, Drizzle
The general trend for this summer will continue - more cool weather is in store for SoCal!
Today’s post will be very similar to the one posted on August 27th. We are once again looking at a big cool down with a chance for drizzle. Here’s the situation we will be looking at:
Synopsis: A trough is currently near the pacific NW. It will make it’s way down the west coast into Northern California. By Wednesday, it is forecast to form into a closed low. Along with the trough comes a deep marine layer (up to 3000+ feet) that will reach all the way to the coastal slopes and bring a chance of drizzle to the area. Temperatures will once again be running well below average for this time of year with inland locations barely reaching the low 80s on Tuesday and Wednesday. In fact, some record lows will probably be set as some inland locations will dip all the way down to the 40s. Given the atmospheric setup this summer, this is not very surprising.
Long-Term: On Thursday, the deep marine layer should still remain in place, but the trough will start moving out allowing for some slight warming. Temperatures will remain below average at least through Sunday.
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Cool Weather to Continue
We are in the midst of a heatwave right now with our inland areas forecast to reach the 100s today (Friday). However, the general trend for this summer has been cool weather, especially for the beaches and that will more than likely continue. After this ridge that will warm us up today to around 90 degrees in Downtown LA moves out, models swing two troughs over the state; the second stronger than the first.
Temperatures will once again return to below average and the marine layer will reassert itself expanding well inland past the usual beaches. Hope you guys are enjoying this relatively cool summer. Yes, we’ve had a few significant heatwaves which broke some record highs, but it’s generally been around or below average.
Beaches will see almost no difference as they’ve been socked in with the marine layer for almost the entire summer. Santa Monica Pier only reached a high of 59F today. The cooler temperatures that will be associated with the troughs that will move through might actually lead to warmer temperatures at the beaches if there is reverse clearing or no marine inversion.
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Yesterday was downright chilly with Woodland Hills, for example, coming in 22 degrees below normal
– NWS Los Angeles/Oxnard -
Feels Like Fall
Yesterday felt more like a fall or winter day in Southern California as temperatures were well below normal for this time of year. Palmdale only made it to an astonishing 74F yesterday, which is about 20 degrees below normal. The same situation was present in many inland areas; here are a few examples:
- Burbank: 73F (-16F from normal)
- Sandberg: 63F (-20F)
- Lancaster: 77F (-16F)
- Campo: 74F (-18F)
- Ontario: 77F (-17F)
- Riverside: 78F (-16F)
Today, the trough that brought us these chilly summer temperatures will begin to slowly move out and a ridge will build into the Southwest by midweek. Temperatures will climb to above normal in many areas once again, but coastal areas will remain cool with a very strong marine inversion in place.
The heat will be rather short lived as another trough will move down the west coast and bring temperatures down a notch as well as increase coverage of the marine layer. Looks like this has been the dominant pattern for this summer.
