WeatherExtreme Forecast Discussion 8/3/2017 1440Z

Once again there are problems with the local WRF model, so this morning’s forecast is based on ECMWF, GFS, SkySight, RAOB and satellite. Thursday should be much improved for flying with a few scattered low clouds in the morning in El Calafate, becoming mostly clear by afternoon. Surface winds out of the west 10-15 kts gusting to 30. Winds aloft west-southwesterly 50-80 kts above FL100. Moderate wave will be present with vertical velocities 1000-1500 fpm, diminishing above FL200. Orographic precipitation and low clouds will be present west of the ridge line.

Jim Purpura of WeatherExtreme Ltd. is guest speaking at Wavelength Brewing Company January 6th.

Jim Purpura CCM, Meteorologist at WeatherExtreme Ltd., will be guest speaking at Wavelength Brewing Company on Friday January 6th at 8:00PM in Vista CA. He will be discussing a new program in Malawai developed by the United Nations (UN) through the World Meteorological Organization (WMO) which aims to create a network of weather watchers who can share forecasts and warnings via cell phone. . The project will merge two systems now being put in place across 9 nations in southern Africa: The Severe Weather Forecast Demonstration Project (SWFDP) and the Southern African Region Flash Flood Guidance (SARFFG) system.

For information on the upcoming event, click here to view the event on Facebook.

In Memoriam of Dr. Kelly Redmond

It is with a heavy heart that we write this…yesterday the world lost a great climatologist and dear friend. Dr. Kelly Redmond of the Western Regional Climate Center passed away. We will miss him and his enthusiasm for the climate and weather of this world! His passion for such things as El Niño, La Niña, droughts, and “blobs” of warm water that appeared mysteriously in the Pacific Ocean will be greatly missed.

From all of us at WeatherExtreme Ltd.



WeatherReady Nation Summer Safety Campaign


WeatherReady Nation Summer Safety Campaign
Summer Safety in the Sierra: Lightning and Flash Floods

Now that Memorial Day is past, schools are letting out for the summer and vacation season has begun. Soon the beautiful Sierra Mountains will become a become an outdoor playground.

In the Sierra, the main summer hazards are Lightning and Flash Floods


Across the US, lightning is, on a annual basis, as much a personal threat as tornadoes. The large number of campers, hikers, and boaters in the Sierra, combined with frequent thunderstorms, mean that summer thunderstorm lightning risk occurs on an almost daily basis here. Know the safety rules: check the weather forecast for the day, watch the sky for signs of thunderstorm development, and know how to stay safe. Safe places include indoors, as long as you are staying away from electrical, plumbing, and landline phones. Inside a metal topped car or SUV is safer than being outside. In short, when thunder roars, go indoors! There is no completely safe location outdoors in a thunderstorm! See for National Weather Service (NWS) safety tips on lightning.

Flash Floods

Another summer hazard in the Sierra are flash floods. Flash floods may develop as little as 10 to 15 minutes after heavy rain begins to fall. The rain may fall on a ridge or mountain top and may quickly move downstream to your location. Dry creek beds or dry washes, and narrow valleys or canyons may be particularly risky. In areas downstream of recent wildfires, rain may mix with mud, ash, and debris from the fire, creating a debris flow. The US Geological Survey (USGS) estimates that as little as a 1/4 inch of rain in 15 minutes in a fresh burn area may be enough to initiate a debris flow.

The safety rule for floods for hikers is climb to higher ground. For motorists, remember Turn around, don’t drown! See for an NWS safety video on driving across a flooded roadway. As little as a foot of moving water can lift and carry a car downstream in a flood.

Jim Purpura
Certified Consulting Meteorologist