Dry End to the Month

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The dry weather should continue through the rest of the week (and therefor the rest of the month).  We will see a warming trend from the low 80s on Tuesday to the low 90s on Friday. As we head into the weekend, the ridge of high pressure will finally break down and allow an opening for low pressure systems to move into the region, although at this time there is a lot of uncertainty as to when any will finally break through. Temperatures will cool over the weekend, dropping to the upper 70s with a few clouds, but we will likely have to wait a while longer before we will see any rainfall

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Getting Warm Again…And How Can The Ground Freeze When It’s Not Below Freezing?

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We will continue with the dry and sunny weather over the next week, with the temperatures starting at about 80 degrees on Monday, and then rising steadily with near record high temperatures in the low 90s expected by the middle to latter part of the week. Once we get past next week there is some indication that the strong ridge of high pressure will start to breakdown and we could see some cooler, and possible even wetter weather coming our way.

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Even though the air temperature hasn’t hit the freezing mark down here in the valley, that doesn’t mean the ground has escaped the frost line. I received a report from a viewer down in the Gardnerville area last week saying that she had a frost (at the expense of her veggie garden) early last week. How can that happen with temps in the 40s?

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It happens more than you might think. During the day, the sun heats up the ground directly (by radiation) to a level much warmer than the air above it. Walk barefoot on asphalt on a sunny day if you don’t believe me. The reverse happens at night. The ground emits radiation energy straight to outer space, leaving the atmosphere mostly untouched. So the ground cools much faster than the air.

 

 

 

Summer Ends on a Dry and Breezy Note

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We aren’t going to end our long dry spell as we say goodbye to summer Saturday (the fall equinox occurs at 6:54 pm Saturday for those of you keeping score at home.) The afternoons will get a bit breezy as a trough of low pressure brings a dry cold front toward us, passing through on Sunday. High temperatures will start in the mid to upper 80s on Saturday before dropping to the low 80s Sunday and Monday, with afternoon winds gusting as high as 30 mph. After the front passes through, temperatures will quickly warm back up to the mid-80s Tuesday and the upper 80s for the rest of the work week.

Summer Finishes Dry

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It looks like our very dry summer will finish out on a very dry note, with no real chance of any rainfall on the immediate horizon. Temperatures will warm from the low 80s on Thursday to the upper 80s Friday and Saturday. A dry cold front will pass by to our north, kicking up some breezes on Sunday and throwing a few clouds our way, but the dynamics and moisture content will be too weak to give us any real hope for rain down this far to the south.
As we head into next week, after a brief drop to the lower 80s, temperatures will warm back into the mid to upper 80s with sunny skies for the duration of the forecast period.

Mild Week…Weekend Changes?

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While we may see a little afternoon breeziness on Tuesday afternoon, the overall weather picture in western Nevada is pretty docile this week, with lots of sunshine and slowly warming temperatures. High temperatures in the low 80s Tuesday and Wednesday will rise into the mid-80s as we head into the weekend, with overnight lows dropping into the 40s and 30s depending on location. With the arrival of the weekend, another trough through the Pacific Northwest will bring some breezes and cooler temperatures, with highs falling to the 70s by the beginning of next week.

A Cool Down Coming

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Temperatures will drop significantly over the next couple of days, and the push of the cooler air into the region will keep our winds at a brisk level, increasing the fire danger in our area. A Red Flag Warning is in effect across northern Nevada and eastern California through Wednesday. High temperatures on Wednesday will drop to the upper 70s, and fall further to the mid-70s on Thursday before recovering back to the 80s by the weekend. A few clouds will pass through the next couple of days, but conditions should remain dry throughout the rest of the week.

Red Flag is Flying Again

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As is often the case, as soon as we get past Balloon Race weekend and into Air Race week, the weather will be changing. A low pressure center off the coast of British Colombia will bring a dry cold front through the region starting Tuesday, cooling us off pretty dramatically, and kicking up some strong winds. There is a Red Flag Warning posted staring Tuesday afternoon for high fire danger, with afternoon winds expected to gust as high as 40 mph by the evening. Temperatures will fall into the mid-80s Tuesday and then drop into the 70s on Wednesday. 70s remain through Thursday and will creep back into the 80s for the weekend.

Cooler Days Ahead… And Two Kinds of Lightning (Pt. 1)

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While we are still likely to add a few more days onto our streak of 90 degree days, there does appear to be some relief from the heat on the way. Skies will still remain mostly clear through the next week, with occasional haze and smoke drifting into the region from the fires to our west, and temperatures will drop by the weekend to around 90 degrees. As we head into the next week, a trough of low pressure will carve out some cooler air into the west coast, dropping our highs down into the 80s, putting an end to the streak.

Lightning bolt

I’ve talked about how lightning forms before. Negative charges from the base of thunderstorms clouds induce a positive charge on the ground, and after a “stepped leader” forms out of the clouds, it causes a “return stroke” from the ground once the negatively charged leader gets close enough to the positive charges on the ground. This generally referred to as “negative” lightning, and is the most common kind. But it doesn’t always work that way… lightning can be “positive” as well. Tomorrow, I’ll tell you the difference.

 

 

Will Our Record Streak End?… And Another Example of the Urban Heat Island.

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The dry and sunny weather should continue through the rest of the week, and we will probably add to the record setting number of days we have broken the 90 degree mark (52 days and counting,) although we could get close to dropping below that mark as high temperatures are expected to barely top the 90 degree mark all week long. Otherwise, sunny skies with moderately breezy afternoons will stay with us through the weekend.

Reno ASOS Location

Lest anyone think that there isn’t an enhanced Urban Heat Island Effect around the airport, all one need do is change their mode of transportation. Here’s an example: I often drive home at night on a motorcycle, and I start right next to the airport. On the way home (a 15 minute trip) I pass by a small field, and the temperature difference often hits me like a hammer… easily dropping 10 degrees in the space of a few hundred feet. It’s quite startling, and it’s a reminder of how cool the airport used to be.

 

 

 

 

Is There Cooling In Sight?… And Why Are The Nights Warmer? (Conc.)

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The dry and sunny conditions will continue through the rest of the week, and although the temperatures will still stay slightly on the warm side of average, they won’t be chasing any records. A low pressure center has snuck into the Pacific Northwest, which will cool us slightly into the low 90s and upper 80s in western Nevada, but the westerly flow will keep our skies sunny and will make our afternoons a bit on the breezy side. Temperatures could finally fall out of the 90s by the start of next week.

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One reason our low temperature is often higher than the “average” is much of our database occurred when the airport was surrounded by irrigated alfalfa fields. This natural swamp cooler makes a tremendous difference… especially in the night time period. Now the airport is almost entirely surrounded by concrete and asphalt. The amount of warming that it can make can be pretty drastic. Just look at differences in places like the airport (the official Reno location) and outlying areas like Spanish Springs or Washoe Valley. All of them are pretty close in elevation and general geography, but the airport can be 10-15 degrees warmer on a clear and calm night, thanks to the heat island.