30 over 3

There is something inherently weird about a weather pattern in which the high temperatures three days apart can differ by (almost) 30 degrees (Fahrenheit).

And I suppose I am in a very tiny minority of San Diego County residents who much preferred the day when it was 103 to the day when it was 74.

(Some like it hot.)

Cold December, Hot January

We are in the midst of a very unusual hot streak. For the seventh straight day here at Ladera Frutal, the high temperature passed 80 degrees (on the quaint Fahrenheit scale). This is quite a contrast with December, which featured seven straight days with a high below 60. I am not sure which 7-day streak would be rarer, but neither could be counted on to occur most winters. To have one such hot and one such “cold” streak in the same winter might just be unprecedented. (The December streak even featured a day when the high was only 49; that’s the only 24-hour period in the six-plus-year history of Ladera Frutal’s weather station to feature a high of less than 50!)

So the weather has been weird. And all this weirdness greatly confuses the fruit trees. There have been a few blooms sporadically on the Earlitreat peach since late December. This is not usually one of our first bloomers–it would usually start in mid-February after a few other peaches–but it always is the first ripener. One year it gave us fruit at the end of April. Maybe this year we’ll have peaches in March!

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And I was out picking the sumptuous new crop of Page mandarins and suddenly my nose detected one of the most delightful of all fragrances. Could it be? Yes, there are a few blossoms on the Page! (Citrus usually start blooming after mid-March.)

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There is still no sign of bud break on the usual first-bloomers: the Mesch Mesch Amrah plumcot, Newcstle apricot, Flavor Delight aprium, or Tropic Snow peach. (There have been blooms on the Anna apple, but that doesn’t count; that crazy no-chill apple always blooms in December.) But with such warm weather, I’ll be surprised if one of these is not beginning to bloom by the end of next week.

Of course a limiting factor in triggering blooms will be whether chilling requirements have been met. In fact, it is precisely to guard against too-early a bloom, with possible later freeze or frost damage, that deciduous fruit trees evolved their chilling requirements. If they have not had their chill needs met, they will hold off at least a little bit longer. But at some point, if the warmth continues, they’ll break dormancy anyway, but may not flower or fruit well.

Despite the warm spell, the chill count is pretty good, thanks to two factors: (1) that extraordinary cool week in December, and (2) the dry air. When the air is dry and there is no cloud cover, the nights can be chilly even when the days get quite hot. And it is with dry and cloudless nights that the full flowering, so to speak, of Ladera Frutal’s microclimates become apparent.

Up here at LF HQ, at one of the highest locations on the finca, the hottest day reached 89. That night it cooled to 56. Down the slope, at the coldest part, where all but the lowest-chill deciduous fruits are planted, the high was a bit lower, at 87. But the following night it got to 45. Yes, a 42-degree difference from high to low, and an 11-degree difference in low temperatures between the two locations! What a difference 100 or so feet of vertical change over 200 or so feet of horizontal can make! And in the protection of the big old grapefruit trees, the hedgerow (where I cheat on chill) stays cooler still: the hottest day was 83, rather than 87 or 89, and it is almost always 1-3 degrees colder at night. At times, even just shortly after sundown, we experience a 9- to 12-degree difference in temperature between the locations. Following Madison’s “scientific farming” principles, we have planted varieties in locations intended to maximize their microclimatic adaptation.

As a result of these microclimate effects and the dryness, the chill count is not too bad. Of course, it is not as good as the December cold seemed to promise, but it’s decent. By estimate it seems to have peaked around 310-320 at LF HQ, although we have been subtracting 15-22 hours a day during the hottest phase of the warm spell and now are probably under 250. By my understanding of chill models (and they are just models, not empirical descriptions) that means anything that needs 300 hours to bloom well would be OK, but anything requiring 400 would now need an additional 150, rather than 80-90 before it would be satisfied. Of course, anticipating that this part of the finca might often get under 300 chill hours, I have planted only low-chill varieties up here. (As well as tender subtropicals here and even higher, though that did not work out so well.)

Down in the corralito, at the lowest part of the finca, the chill count is much more impressive. We probably already had 265- 280 by the end of December, and with the impressive cold air drainage down the slope on these dry and cloudless nights, we have had very few significantly negative days. (In fact, at the coldest hedgerow location, none, unless you consider one night of an estimated -.25 chill hours to be “significantly negative.”) Thus down there the trees that are most exposed (to the air mixing of wind and to daytime sunlight) may have had no less than around 350 hours at their peak, while the more protected ones may have had as much as 375 even now (and counting!).

So as long as the heat wave breaks soon and we get even “normal” temperatures for a change, there remain grounds for optimism about the fruit season to come. The forecast calls for only moderate cooling for the next few days, but then a “pattern shift” by the middle of next week. If we are lucky, maybe the rains will return, too.

A blanket of chill

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The fog was dense this morning, and is unlikely to break completely before sundown. Viewed from LF HQ, and looking out over our house below, one can just make out a little bit of our driveway and the grapefruit grove. Somewhere just to the right of the palm you can see the corralito. Oh, you can’t? Well, it helps when you know it’s there.

Down at corralito level, the fog is not quite as visible, but the deciduous fruit trees are being treated to a nice chill-containing blanket.

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Thanks to the fog, the temperature stayed chilly. It did not even reach 45 till after 10:00 a.m., nor 50 till after noon. That meant many hours of chill accumulation, which should be great for the Shaa Kar Pareh apricot (foreground), and the cherries (back by the fence).

It has been a chilly winter so far, with more than 225 chilling hours accumulated at almost all levels of the finca, thanks in part to an unusually high number of days with lows in the 50s (and one that did not even get that high). And, while normally the chill is significantly less up the hill (due to cold air drainage down the steep slope) this year there is little difference, in part due to some near- or sub-freezing nights at the corralito. When the temperature is in the mid 30s and below, there’s little or no chill accumulation. (Prime temperatures for chill are about 38-45, and anything up to the mid 50s is still weakly positive.)

Late next week it may get rather warm. That will slow down the chill accumulation. But 225 hours is a good total as of the first of January, especially as some warm days at the start of December meant we did not really get started till well into the month. If we get another cold snap or two later in January or early February, 2009 might be another good year for the deciduous fruits.

Unsettled

This is not the sort of forecast we have in these parts very often:

TONIGHT… SHOWERS LIKELY… POSSIBLY MIXED WITH SNOW NEAR THE FOOTHILLS.

Nor this:

WEDNESDAY… SHOWERS… POSSIBLY MIXED WITH SNOW NEAR THE FOOTHILLS… AND A SLIGHT CHANCE OF THUNDERSTORMS. SOME THUNDERSTORMS MAY PRODUCE SMALL HAIL. HIGHS 51 TO 56 IN THE WESTERN VALLEYS TO 43 TO 48 NEAR THE FOOTHILLS.

Some places a little east of Ladera Frutal may have highs in the low 40s (on the quaint Fahrenheit scale)?

Evidently, chill-accumulation season is underway. Ladera Frutal no longer has any tender subtropical fruits trees to worry about, their having been wiped out in The Freeze of 2007. The under-ripe bananas on some of our stalks may stay that way, however.

Microclimates

I’m always amazed by large temperature variations over short distances. This morning’s 9:00 a.m. version of the regular forecast discussion noted:

TEMPERATURES THIS MORNING WERE INTERESTING TOO BECAUSE OF THE LOCALIZED WINDS. WITHIN THE CITY OF RIVERSIDE AT 6 AM THE AIRPORT WAS A WINDY 79 DEGREES WHILE MARCH FIELD WAS VIRTUALLY CALM AND 49. [CAPS theirs]

Those locations are less than 15 miles apart.

Here at Ladera Frutal, just over 50 miles south of March, we hit a low of 55 shortly before six this morning. And we got to 96 during the day. Yes, it’s feeling a lot like fall around here!

Cloud renewal

After a summer of mostly monochromatic skies–either whitish grey ((The pattern known officially by the Ladera Frutal Weather Service as “marine crap” has been unusually persistent through July, despite notably less of our usual May greyt and June gloom in the preceding months.)) or blue ((Monochrome may be sort of boring, but when it’s blue, I will take it!))–we finally have had some southeastern (“monsson”) flow to make the skies a bit more interesting.

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Look closely at that last one and you will see the almost half-moon, on this 7th day of Avchadeish yameinu kekedem.
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Just plain crazy

So, what was it I was saying about evidence of spring? So, on the 14th of February, the temperature was below 45 almost all day long. That is unheard of in these parts! And for the period from sundown on the 13th till sundown on the 14th, the high was reached overnight, while the low (41) was reached around 1:00 p.m. Weird. And it was raining most of the morning and early afternoon while the temperature was in the low 40s. It is never that cold here when it is raining.

No wonder the forecasters did not see this coming. No model could predict something so out of all normal weather patterns!

Local snow levels around 1500 feet, and quite cold (freezing?) temperatures expected tonight.

An inexact science

So, after barely running the irrigation since November, yesterday it seemed time to put some of that expensive municipal water on the groves. No rain was in the forecast, a once promising trough of low pressure for 14 February having changed trajectory and expected to go east of us. Drying winds and continued warmth were in the forecast, after a week of temperatures in the 70s and even over 80. Yes, clearly time to irrigate…

Today it is raining. The temperature has not broken above 47 since about 8:00 this morning. Up to a half inch is expected.

Sometimes the forecasters just get it wrong. Not very often, actually. And a forecast for no rain followed immediately by a day of rain is really rare here.

To their credit, the forecasters keep up links to several forecasts–and the accompanying discussions, where they indicate the models they are using and any doubts–in addition to the current one. And not until about 5:00 this morning was there even any mention of a slight chance of rain. Even at 5:00, the rain chance for the day was given as 30%. It started raining around 7:00, and a forecast issued about the time it started to rain actually downgraded the chance from 60% to 50%. Oops!

By 8:55 a.m. the discussion noted:

NWS DOPPLER RADAR SHOWS NUMEROUS SHOWERS OVER THE CWA [forecast areas] THIS MORNING
WITH SNOW SHOWERS REPORTED IN THE MOUNTAINS…EXTENDING TO SOME
AREAS OF THE INLAND EMPIRE DUE TO LOW WET BULB TEMPERATURES.
DARKENING IN THE WATER VAPOR IMAGERY INDICATES A VIGOROUS SHORT-WAVE
TROUGH DROPPING S THROUGH CA THIS MORNING…

EXPECT VIGOROUS SHORT-WAVE TROUGH WILL DRAW COLD UPPER LOW TO THE
SW…OVER SOCAL BY LATE TODAY. THIS WILL KEEP UNSTABLE CONDITIONS
AND CLOUDS OVER MOST AREAS WEST OF THE MOUNTAINS…

(No, I have idea what “low wet bulb temperatures” are, but I like the way it sounds.)_

Forecasting is an inexact science. And so is knowing when to irrigate. No doubt, had I not turned on the irrigation, it would not have rained.

From the top of the finca

The snowfall got pretty low overnight. I can’t remember the last time I saw snow this low.

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This view is from the highest point of the finca, just past the final stop on the Ladera Frutal Incline Railway. The view is to the northeast, towards the Palomar Divide. In the foreground are the massive avocado groves on the other side a narrow canyon, and just west of Interstate 15.

These mountains are about 15 miles away, though on a clear day like today, the sure look closer. Parts of the lower elevations on this snow-dusted ridge burned in the Poomacha Fire during the wildfires of late October.

Update: Next time the ridge was visible, on 15 December, the snow appeared to be gone already. That did not take long.

Sunsets before the storm

As I mentioned in regards to Friday’s storm, the cutoff low that produced the rains drifted off the Baja coast for a few days and brought us some very interesting clouds–teasing us with what might be coming.

And interesting clouds mean nice sunsets.

For instance, Tuesday night’s.

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It was all the more remarkable in that this band of clouds was the only part of the entire sky that was not clear at the time.

Thursday’s was not too shabby, either.

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The next storm

Wow, this sounds impressive (despite the caveat at the end).

In a winter forecast to be drier and warmer than normal due to the moderate, but strengthening, La Niña, we need all we can get when we can get it. And a “classic Pacific storm” spinning off a low over Kamchatka would be most welcome.

Quotation from forecast discussion relegated to inside branch. Continue reading

Let it pour

I do not remember when I have awakened to be more thrilled at the sounds of the morning. It is raining. Seriously raining. Already about .40 inch as of 7:50 this morning.

I know there are parts of the County–recently burned areas–that will suffer from heavy rain. But we need it badly, for the fruit trees, for reducing the fire risk (even for a little bit), and, yes, for our souls. What a beautiful, calming sound! I had almost forgotten what it was like. The last significant rain was many months ago.

This is one of those cutoff lows (weatherman’s woes). It has drifted for days off the coast of northern Baja and given us interesting high clouds and gorgeous sunsets (I may post a photo or two later)–and given the forecasters challenges in predicting where it would wind up. Well, now we know. Right here! And we are under a flash-flood watch till Saturday afternoon.

Let it pour (but not too hard).

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This morning’s forecast discussion appears to downplay, in advance, what has in fact materialized. And no, I really do not understand all this jargon, but it sure sounds good:

BELIEVE AMOUNTS WILL BE LIGHT DUE TO CONFLICTING JET STREAMS AS THE TWO SYSTEMS COLLIDE. THERE IS NEVER CONSISTENT JET DYNAMICS TO GET MOIST ATMOSPHERE TO LIFT SUBSTANTIALLY. HOWEVER… QPF SHOULD INCREASE THIS EVENING WHEN THE SYSTEMS PHASE…WHICH WILL ALLOW BAROCLINICITY TO PRODUCE RAPID CYCLOGENESIS.

100,000

Some time in the next few hours (it is now 3:40 p.m., local time), the 100,000th visitor will have been to the virtual orchard, according to Sitemeter.

Congratulations to whoever you are. Not that there is much reward, but someone has to be the one who turns the counter to such a nice round number. If no. 100,000 is ever at the real orchard, I will offer him or her some free fruits. (I have no votes to give away. I have done enough of that over the years: I used to vote for Democrats.)

Also an update on local conditions: Air much better today, Sky blue, other than a few high clouds. The air was still a little bluish this morning when there was fog. Breathing better, but still feeling the effects (including occasional rather violent coughing). Spent most of the day sweeping and dusting. Amazing that even indoors, in a building that was mostly closed up during the worst, there could be so much dust and fine ash from the fires.

Blogging activity will remain minimal while catching up on work and recovering from the physical and emotional stress of the preceding week.