September 28

Drought Worsens Over Western USA – New NOAA GEFS Model Upgrade Now Looks Out 35 Days

NOAA Takes Steps To Catch Up to ECMWF

For the record, I’d like American Exceptionalism to apply to weather model accuracy. My take: The National Weather Service is the best on the planet, but in recent years the ECMWF (European Centre for Medium Range Weather Forecasts) has been more accurate. Not perfect, but better than NOAA’s models many days.

That may change with the recent overhaul of NOAA’s GEFS (Global Ensemble Forecast System) FV3, which reduces resolution to 25km, with better physics – able to peer out 35 days into the future. Stay tuned, and good luck with all these odd acronyms.

NOAA Upgrades Global Ensemble Forecast System (GEFS). NOAA explains: “…With the inclusion of the FV3 dynamical core, GEFS resolution has increased from approximately 33km to 25km, and the number of individual forecasts input into the ensemble has increased from 21 to 31. These changes will allow models to run at a higher resolution of detail and provide better accuracy. Additional upgrades include extending the forecast length from 16 to 35 days, along with improvements to the physics. GEFS attempts to quantify the amount of uncertainty in a forecast by varying the known inputs to multiple forecasts, thereby generating a range of possible outcomes. “This GEFS upgrade continues the ongoing revolution of numerical modeling that began with the introduction of ensemble modeling into operations over 25 years ago,” said Louis W. Uccellini, Ph.D., director of NOAA’s National Weather Service…”

Lukewarm Second Week of October? After next week’s chilling correction I see more of a zonal, west to east wind flow returning within 10-14 days, meaning 60s and a few 70s possible. Don’t write warmth off just yet.

Why the 2020 Atlantic Hurricane Season Has Spun Out of Control. Jack Henson reports for Capital Weather Gang: “…One of the most obvious culprits is La Niña, whose arrival was confirmed by the National Oceanic and Atmospheric Administration on Sept. 10. La Niña, a semiregular cooling of the eastern tropical Pacific, tends to reduce the wind shear that can impede Atlantic hurricane formation. A La Niña is only present about every third hurricane season, though — so by itself, it doesn’t fully explain why 2020 is so extraordinarily active. Sizzling oceans, supercharged by climate change, may be an even bigger factor. Most of the tropical and subtropical Atlantic, including the Gulf of Mexico, has run warmer than average through the season, with sea surface temperatures (SSTs) at or near record values in some areas…”

NOAA Declares La Nina is Here. The Washington Post’s Capital Weather Gang discusses the potential implications (for hurricane season and the upcoming winter) by a cooling phase in the Pacific Ocean: “The National Oceanic and Atmospheric Administration declared Thursday that a La Niña pattern had become established, having bearing on the remainder of the hurricane season and the upcoming winter. La Niña conditions are likely to continue through at least wintertime, potentially returning to a more relaxed “neutral” state by spring. La Niña, which means “the girl” in Spanish, is the opposite of an El Niño. La Niña features unusually cool ocean waters in the equatorial tropical Pacific Ocean and can influence weather patterns beyond the Pacific. The expectation of a La Niña pattern was a contributor in NOAA’s early August forecast of an “extremely active” hurricane season...”

Map credit: “Current sea surface temperature anomalies in degrees Celsius. Note the cool waters in the eastern Pacific commensurate with La Niña.” (Tropical Tidbits).

California Fires Tornadoes Had Winds Up to 125 MPH. Capital Weather Gang has the jaw-dropping specifics: “California’s Creek Fire, which has torched almost 300,000 acres and become California’s largest wildfire on record, was still only a third contained as of Wednesday. Like other blazes this year, it grew rapidly during periods of hot and dry weather with strong winds, burning tens of thousands of acres in a single night. Now we know that the fire featured a rare phenomenon that demonstrates just how extreme it was, with the National Weather Service’s announcement Wednesday afternoon that two fire tornadoes were associated with the blaze. The two vortices, one rated an EF2 while the other was an EF1, were produced by the fire, as the extreme heat from the blaze and towering smoke plume above it essentially created its own weather...”

August Complex Fire Now the Largest in State History. ABC7 in San Francisco has the story: “The August Complex Fire currently burning in Northern California is the largest fire in the state since record-keeping began, according to data from CAL FIRE. Several other fires that started in August have also climbed the list of the largest in recent history, including the SCU and LNU Lightning Complex fires and the North Complex Fire…”

Image credit: “The August Complex Fire in Northern California is now the largest fire in the state since record-keeping began. Several other fires that started in August have also climbed the list of the largest in recent history, according to data from CAL FIRE.”

Few Resources, Old-Growth Forest Allowed for Fire’s Growth. And a warmer (drier) climate is part of the equation, according to Associated Press: “…Numerous studies in recent years have linked bigger U.S. wildfires to global warming from the burning of coal, oil and gas, especially because climate change has made California much drier. A drier California means plants are more flammable. The Bobcat Fire was one of more than two dozen major wildfires burning across California, including five of the largest in state history. Twenty-six people have been killed. Officials were investigating the death of a firefighter at another Southern California wildfire that erupted earlier this month from a smoke-generating pyrotechnic device used by a couple to reveal their baby’s gender...”

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