WEATHER IN THE FOOTHILLS

“When one has tasted watermelon he knows what the angels eat.”
~ Mark Twain


Watermelons? Well, let me explain.

While driving by the grocery store a few days ago, I was shocked and also a little saddened. The giant green and red watermelon-decorated cardboard produce box was gone from the front of the store. In the still of the night (I imagine), it had been replaced by a giant green and orange pumpkin-decorated cardboard box overflowing with – well you can guess. Wait a minute – it is still summer and I want just one more sun ripened watermelon. I found they had been moved back inside the store. I left with one of each!

This edition of the CV Weekly is the last one for the summer, as fall begins Friday. The weather normally goes back and forth between the two seasons before settling into a more fall-like pattern.

Southern California’s mild climate makes it hard to identify the seasons by the weather. People who live in or come from other parts of the U.S. often comment on our lack of “real seasons.” I guess there is no absolutely perfect place to live, but the Crescenta Valley is pretty close.

With warm temperatures and green leaves still hanging on, will there be any changes to indicate autumn has arrived? Pumpkins at grocery stores are a good start, but don’t count on the weather yet. One term I’m sure you have heard Fritz Coleman and Dallas Raines use many times is “cutoff low.” Not only difficult to understand, but predicting weather with any certainty is a meteorologist’s nightmare. As I continue to check the National Weather Service’s forecast for this week and next, reference is made over and over again to a cutoff low hovering over southern California and its possible effects on the weather. The following is an attempt to make the complex simpler to understand.

Eight to 10 miles above the earth’s surface are strong wind currents, blowing from west to east – the westerlies. And within these are the even stronger jet streams. Sometimes the two terms are combined and called a westerly jet stream. Occasionally a counterclockwise wind system will separate from the jet stream creating a cutoff low. This independent little jet can affect local conditions greatly. You never know how long they’ll stay. They are slow moving and bring cloudy and sometimes very rainy weather. Cutloff lows will eventually dissipate or join up again with the westerly flow. This atmospheric phenomena is causing major headaches for the NWS and their predictions for our area.

This is the scientific consensus of opinion (more or less) for the upcoming days. Thursday and Friday: possible temperatures in the 90s and Santa Ana winds.   Then a quick change as the forementioned cutoff low might create a cooler and foggy weekend.

As to next week’s weather … well it can be said, “It has been left up in the air!”

Sue Kilpatrick is a
Crescenta Valley resident and
Official Skywarn Spotter for the
National Weather Service. Reach her at  suelkilpatrick@gmail.com.