Tuesday, August 25, 2009

Heat + Drought = Fire

My first real close experience with a wildfire (since the days of seeing Pinelands fires in NJ from 30 miles away as a kid) occurred today. A 250 acre fire broke out in Angeles National Forest this afternoon, about 15 miles to my east, north of Azusa.


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I happened to wake up from my daily nap to the hum of news helicopters passing by. I looked out my window, and I saw this interesting scene:


It's nice to know I live in the middle of a city, so I'm not at risk here, but it certainly can be slightly frightening.

Downtown LA hit 89 degrees this afternoon. Burbank hit 94, Riverside 99, Ontario 99. It's heating up, and what's scary is that this is only the beginning. Riverside and Ontario may top out over 105 by Thursday or Friday. Burbank should easily hit 100, and Los Angeles could hit 95 or better. By far, the hottest weather of the season. We're certainly not alone. Phoenix and Vegas are progged to hit 105-110 easily. Phoenix should top out over 110. We may not get much relief out here until Sunday, if not Monday. Going to be a rough couple of days.

The only saving grace is a lack of wind. This isn't a Santa Ana event, so we're not dealing with those fire whipping winds every day. But, with relative humidity plummeting and temperatures soaring, fire risk will remain extremely high. Hopefully we can escape this without many big problems.

Sunday, August 23, 2009

It Feels Like the East

So much for blogging regularly.

Monsoon

It definitely feels like the East here today, as monsoonal moisture, which crept in Friday, was firmly entrenched in the area yesterday and today. This spells higher humidity for a change. Of course, most of the area didn't see any thunderstorms unfortunately, but some parts of SoCal did, including the San Bernardino Mountains, and areas north of LA. I guess temperatures were the interesting weather feature Saturday. Ontario hit 95, Riverside hit 96...balmy. More interestingly, LAX hit 81° on Saturday, which is the warmest they've been since the mid-April heat wave!

The real, true heat was short lived though, as a Catalina Eddy spun up this morning and is holding temperatures down 3-5 degrees in most areas, so back to reality for a change.

June Gloom

Sure, it's August. But June Gloom type weather has been dominant out here most of the month. That pattern looks to return starting perhaps Monday, as the cut-off low responsible for keeping the marine layer locked in all of last week actually swings through. We may not see the marine layer get all the way inland like it had been last week, but clouds are likely in most of the immediate LA area before burning off mid morning. This pattern looks to stay with us through Tuesday and perhaps Wednesday.

Late August Recovery?

Starting on Wednesday however, a pretty big ridge of high pressure is forecasted to begin building over the intermountain West. This should at least allow for a warm stretch of weather on Thursday and Friday for most of Southern California, except at the immediate coast. Then, depending on what model you believe, either a weak cutoff will develop offshore, likely increasing the marine layer (though the Inland Empire and deserts will likely still cook), or a weak disturbance spinning off the upper low in the Gulf of Alaska is going to pinwheel into the Northwest and lead to a ramping up of the marine layer perhaps for next weekend.

What About Early September?

I know. We're getting a bit ahead of ourselves. But if you look at the climatology of Southern California, the warmest weather of the year is from roughly Aug 28-September 10th. The general rule of thumb is that typically, you can get your first real cool autumn air mass diving into the Great Basin around this time. That often translates to a Santa Ana event in SoCal, which leads to some of the year's hottest weather. The GFS model runs through September 8th today. There is nothing at all showing up on that model that would suggest an early season Santa Ana. Since 2000, there have been seven years which included a heat spike or Santa Ana event in that time period (late Aug/early Sept). So it would be trendy to forecast at least one period of substantial heating thru 9/10. Whether or not that happens remains to be seen. The last panel of today's GFS model shows a slightly deeper trough off the NW Coast. If that can swing inland to the Great Basin, that could be what's needed to generate this chain of events. But that's over 300 hours away...eons in meteorology. That said, having no solid Santa Ana signature right now is a good thing, given how dry the region is. We'll see.