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December 2022 EZNews

Updated: Dec 5, 2022

Hello again and thanks for reading the 20th edition of EZNews!

We appreciate those that have recently joined, renewed their membership or signed up for auto-renewal. We truly appreciate your generosity which helps support our continued innovation moving forward. There have been no new releases this past month with only a few minor changes to the EZWxBrief Pilots Guide. We look forward to more continued growth with the development of EZWxBrief v2.0 and for all members to enjoy the simplicity of EZWxBrief in the coming year. Hope everyone has a Merry Christmas and a Happy New Year!

Here are what others have been saying about EZWxBrief

We appreciate all of the kind words and other feedback. Here's just one of those that exemplifies many of the emails we receive each and every month.

"My undergraduate is chemical engineering so I love data. I also understand engineers usually either fix or build things. However, it's rare that I find solutions like yours: a highly technical matter (weather) translated into easily-understood operational knowledge for appropriate decision making. I hadn't flown for 17 years due to a medical issue so diving into the deep end of the new graphical weather pool was a shock. Gone are the days of being proud I could correctly translate METARs, TAFs and Area Forecasts.

Your EZWxBrief has been a god-send in making the transition and keeping me a very safe pilot. My pilot friends know I'm not easily impressed with things so they've taken note of my high praise and referrals to your website. While they might not be as impressed as I given their more recent flying experience, I'm sure they'll find its easy of use and "English" translations of weather to be as useful as I did. Thank you a wonderfully useful (and accurate) product!"

- Al Z.

"I want to support you because what you have created is truly valuable, not just to me but for all who use it. It’s truly the best of the best of resources. Thanks for all the hard work…and for all your contributions also to Pilot Workshops, another 'top tier' provider of pilot training. Amazing stuff."

- Keith A.

Check out The Daily EZ Weather Brief

On Tuesday, November 15th, Dr. Scott Dennstaedt has rebooted The Daily EZ Weather Brief. It is being broadcast live on the EZWxBrief YouTube channel at 7:30 a.m. eastern time Tuesday through Friday (excluding holidays, illness and travel). Check the community page for the channel for changes to the current schedule. The goal is to provide general aviation pilots with a brief overview of today's aviation weather impacts across the conterminous U.S. and southern Canada. Please note that this live broadcast and recorded video is for educational and entertainment purposes only and should not be a substitute for a formal weather briefing as required by 14 CFR 91.103 (a). Take a minute and subscribe to the channel (@ezwxbrief). More importantly, please let other pilots know about this opportunity!

WRF-ARW forecast radar static weather imagery moved

To keep consistency between forecast models, the WRF-ARW forecast radar has been moved in the EZImagery to be now located under the HREF Model forecasts. Any favorites that you current have for the WRF-ARW forecasts should not be affected by this change.

SLD threats in EZWxBrief explained by the Skew-T log (p) diagram

The EZWxBrief progressive web app does a pretty nice job depicting where the primary supercooled large drop (SLD) threats are located along the proposed route of flight. With an active route, while on the EZRoute Profile select Icing and then select the SLD attribute as shown below. Notice that at 10,000 feet on a route from Corpus Christi, Texas to Lubbock, Texas departing at 21Z there's a potential of 56% of encountering SLD.

Let's take a look at a Skew-T diagram near this particular location. There's a lot to unpack in the 8-hour forecast sounding below. First, notice that there's a rather deep saturated layer from 6,000 feet to 12,500 feet MSL. The entire saturated layer is all below 0°C. This identifies a fairly high potential for airframe ice between these two altitudes. But what is causing EZWxBrief to determine the potential for SLD between 10,000 and 12,000 feet as shown above?

The first thing to notice is that the saturated layer has a lapse rate that slightly exceeds the moist adiabatic lapse rate (MALR) between 10,500 and 12,500 feet MSL. The MALR is generally Mother Nature's lapse rate limit for saturated air. Given that it is slightly greater than the MALR, the atmosphere can wring out a ton of liquid water content.

The other thing to notice is that the tops of the clouds have a cloud top temperature of -8°C. This creates a situation where there is little chance for ice crystals to form and therefore, the clouds below are likely to be in a liquid state. Lastly, given the stable lapse rate below, condensation nuclei are limited from mixing up into the tops of this cloud deck. This creates a condition where drop sizes get larger due to the limited number of nucleation sites available. Put this together with high liquid water content and a supercooled large drop potential, this is why EZWxBrief was sounding the SLD alarm.

Tis the season for downsloping winds

November begins the season of downsloping winds. You may be more familiar with terms such as Santa Ana winds, Chinook winds or perhaps sundowner winds. These are all examples of the downsloping wind effect. Essentially, when air flows down the side of a mountain range to the surface, it compresses and heats up. In many locations such as southern California, these winds and dry out the air to the point where there's an extreme fire danger. Outside of convection, these conditions often create some very intense low-level turbulence events.

On November 15-16, 2022, southern California experienced a Santa Ana event. Gusty Santa Ana winds had peak wind gusts of 94 mph at Marshall Peak, 87 mph at Arrowhead Springs, and 85 mph at Fremont Canyon. The minimum daytime relative humidity fell to 8 to 12 percent during this time. The low humidity in conjunction with gusty winds will create periods of elevated to critical fire weather conditions.

The most phenomenal of all known sundowners occurred on June 17, 1859. It was recorded in historic texts from those living in 19th century California as a frightening event without parallel in weather records in that part of the world. An engineering boat from the “U.S. Coast Survey” fortuitously anchored near Santa Barbara monitored the weather that day and issued a report on its observations.

The ship record states that temperatures reached into the mid 80s by mid morning and no unusual weather was noted. At approximately 1 p.m., gusty northwest winds developed “from the direction of Santa Ynez Peak” accompanied by a sharp temperature rise and a severe dust storm. The storm “filled the inhabitants (of Goleta) with terror; they thought the end of the world had come.” At 2 pm, the survey boat recorded a temperature of 133°F (56°C) in heavy blowing dust. Animals died in the fields, wild birds dropped from the air dead, and fruit and vegetables were “scorched on the windward side.” The survey report stated that “no human being could withstand such heat.” Santa Barbara’s world record remained for 75 years, until it was beat by a single degree by weather in the Mojave Desert recorded at Death Valley.

Looking for a gift for the holidays?

Perhaps you'd like to give the gift that keeps on giving. Give the gift of knowledge to your CFI or other aspiring pilot. Or perhaps you'd like to give your spouse a gift idea for them to put under the Christmas tree. If so, then purchase The Skew-T log (p) and Me: A primer for pilots and Pilot Weather: From Solo to the Airlines combo deal. You can purchase a both soft cover books for a low price of $99.95 plus $10 shipping. This offer will be available through December 15th.

Most pilots are weatherwise, but some are otherwise™

Dr. Scott Dennstaedt

Weather Systems Engineer

Founder, EZWxBrief™

CFI & former NWS meteorologist

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