Ridge of high pressure creates sweltering situation

pgeweather@pge.comJuly 7, 2012 

I’m not a big fan of hot weather. Sailing in the Persian Gulf on the USS Estocin (FFG-15) during summer in the mid-1980s was a scorching experience.

The air temperatures never seem to cool. After each flight in our Kaman SH-2F Seasprite, a ship-based helicopter, it was my responsibility to climb to the top of the helicopter and grease the main and tail rotors. At times it was so hot, the red-colored grease would lose some of its viscosity and came out of the grease gun more like 90 weight oil than waxy jelly. Glimpses of the gulf waters through the tail rotor inspired foolish notions of jumping in to cool off.

I feel fortunate to live in coastal California where blistering hot days are few and far between. The same thing certainly can’t be said for much of the rest of the country this year. A strong and nearly stationary ridge of high pressure centered over the Midwest has forced the jet stream far to the north. This condition has produced one of the worst heat waves and droughts on record. Consequently, raging wildfires have destroyed hundreds of homes in the Rocky Mountains and bone-dry soils threaten vital crops, like corn and soybeans, in the Midwest.

About the only relief from the three Hs — heat, haze and humidity — have come from fast-moving and violent thunderstorms that briefly cool the atmosphere, but also cause extensive damage. Many of these storms have produced brief periods of hurricane-force winds that have toppled trees onto power lines and produced widespread electrical outages. Millions of homes have lost electricity this year and the air conditioning, which it provides. Tens of thousands of homes are still without power.

According to the National Oceanic and Atmospheric Administration, this year has seen nearly 41,000 temperature records broken, an astounding number to say the least. After an unusually warm winter, that’s almost twice as many broken temperature records as this time last year.

With all things being equal, during a normal year, you would expect a ratio of one high to one low temperature record broken. However, over the last few decades this ratio has changed to two record highs for every record low. So far this year, between seven and 10 high temperature records are being broken for each low temperature record. Even more troubling, the hottest temperatures usually occur in late July and August.

In fact, according to historical temperature records from NOAA, current temperatures are significantly hotter than the 1930s. That decade experienced prolonged droughts, which contributed to the disastrous Dust Bowls.

Last year, no other place in the country suffered more from that than Texas. During August, the state’s overnight minimum temperatures averaged 82.5 degrees. The next warmest August on record occurred the year before which averaged 79.0 degrees.

In a hundred plus years of weather records, the all-time high minimum temperature for Dallas was 85 degrees. Dallas tied or exceeded that 10 times last year.

From my experience, it’s not the daytime heat that’s particularly brutal, but sweltering nights. Along with the heat, Texas experienced a devastating drought that cost the state more than $5 billion.

This year, the record-breaking temperatures and drought are shriveling corn and other crops in the Midwest. According to the National Weather Service, drought conditions are present in 56 percent of the continental U.S. The Department of Agriculture estimates that nearly a quarter of the corn and soybean crop is in poor or very poor condition. To make matters worse, the brief period of pollination is occurring in many parts of the Midwest with little success as the drought and heat worsens, which could cause even more significant crop loss. If weather conditions don’t quickly improve, we may all be paying higher prices for food this fall and winter.

Today’s weather report

A strong temperature inversion layer combined with gentle to moderate (8- to 18-mph) northwesterly (onshore) winds will continue to produce mostly overcast conditions along the beaches through Monday morning. The coastal valleys will clear by afternoon.

The high pressure system that brought record hot temperatures to much of the Midwest will push westward into California and the Southwest today, resulting in above normal temperatures across the North County. However, the stubbornly persistent marine layer combined with the northwesterly (onshore) winds will keep the coastal valleys and beaches near seasonal normal temperatures.

Today’s high temperatures will range from the low to mid-60s along the beaches. The coastal valleys will range between the high 70s and low 80s, while maximum temperatures in the North County will reach the high 90s.

As the week progresses the ridge of high pressure is expected to strengthen and will bring 100 degree temperatures to the North County with Tuesday and Wednesday the hottest days of the week.

Moderate to fresh (13- to 24-mph) afternoon northwesterly winds along the coastline Monday through Friday should be just strong enough to produce clear to partly cloudy skies along the beaches during the afternoon hours.

Cooling is expected to push into the North County on Friday with near normal temperatures by next weekend.

Today’s 3- to 5-foot northwesterly (300-degree deep-water) swell (with an 8- to 10-second period) will remain through Monday morning.

A 3- to 5-foot northwesterly (310-degree deep-water) sea and swell (with a 5- to 9-second period) will develop along the Pecho Coast on Monday afternoon and will remain at this height and period through Saturday.

Arriving from the Southern Hemisphere: An energetic storm developed about 500 miles to the east of New Zealand last week. Today’s 2- to 3-foot Southern Hemisphere (225-degree deep-water) swell (with a 15- to 17-second period) from this storm will gradually decrease 1 to 3 feet on Monday (with a 14- to 16-second period).

The long-range charts and models are indicating little storm activity in the Southern Hemisphere for an extended period.

Seawater temperature will range between 52 and 55 degrees through Saturday.

Did you know?

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John Lindsey is a media relations representative for PG&E. He is a local weather expert and has lived along the Central Coast for more than 25 years. If you would like to subscribe to his daily weather forecast or ask him a question, send him an email at pgeweather@pge.com.

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