pollo a la brasa y una cerveza ~
rŌbert 1948 –
pollo a la brasa y una cerveza ~
rŌbert 1948 –
This summer sucks… the energy out of many of us with this prolonged drought and heat. Today, Thursday, may be the warmest day of the year so far. We are expecting 103-105 here in Grand Junction today.The monsoon oozed in from the south over the last few weeks. It has brought some heavy showers as far north as the San Juans. Most sites to our south have struggled with below normal rainfall too.The rest of western Colorado keeps waiting for the rains, and there is a chance this weekend. The subtropical High is currently centered over the southern Great Basin but will shift east into the weekend. This will let the better moisture work up across most of Colorado. The High center returns after Monday next week which will again limit moisture to the Four Corners and points further south.Otherwise no other surprising climate news. CPC’s new monthly and seasonal outlook shows a tilt towards hot and with an active monsoon. El Nino is still favored for the fall and early winter. El Ninos tend to produce above normal precipitation for the fall season and above normal winter snowfall for the San Juans.
With wildfires raging and cities facing record highs, everyone could use a bit (or a lot) of rain. Luckily, summer monsoon season is on the way, possibly as soon as the end of this week. Mike Nelson, Channel 7 meteorologist and author of “The Colorado Weather Almanac,” talked to Colorado Matters about what we can expect in the forecast.
Nelson thinks monsoons will hit their regular schedule in the second half of July throughout August. Unlike the dryer storms with gusty winds Colorado’s experienced thus far this season, monsoons bring the rain. Just one inch of rainfall from a monsoon storm over an acre of land equals 27,000 gallons of water — a hopeful promise for wildfire fighters.
The blistering temperatures last Friday occurred against a backdrop of more-intense hot-air masses due to climate change.
Multiple analyses have shown that the strength of heat domes, the bulging zones of high pressure that are the source of extremely high temperatures, has trended upward in recent decades.
An analysis conducted by meteorologists at the National Weather Service in State College, Pa., and Pennsylvania State University found an increase in the intensity of heat domes over the entire Northern Hemisphere during the summer months from 1979 to 2010.
The intensity of heat domes is evaluated using a measure known as “geopotential height,” which is the height in the atmosphere at which 500 millibars of pressure occur. The higher this pressure level is, the hotter it is, because hot air is less dense than cold air and fills more space. The most intense heat domes, which are extraordinarily rare, feature geopotential heights exceeding 6,000 meters at their core.
Friday’s heat dome exceeded the 6,000-meter geopotential height threshold in several locations in the Western United States and was nearly that high (5,940 meters or higher, as shown within the red outline in the image below) over a sprawling area from Southern California to southern New England.
Data shows that hot domes this extreme are becoming more common. Last summer, Ryan Maue, a meteorologist for Weather.us, examined data back to 1958 and found almost all of the heat domes exceeding this 6,000-meter threshold in the Western United States have occurred since 1983 — with the overwhelming majority forming since 1990.
Because of the warming climate, “I’d surmise that the [6,000-meter] threshold — while an arbitrary big round number — is now more easily exceeded,” Maue told the Capital Weather Gang.R
The Climate Prediction Center recently released their latest monthly temperature and precipitation outlooks for July 2018. Odds are favoring wetter than normal conditions developing across much of the southwestern United States, especially in the Four Corners area. The wet conditions look to continue through September as the CPC’s three month outlook (including the months of July, August and September) shows odds favoring above normal precipitation. As far as temperatures are concerned, odds favor warmer than normal temperatures across Utah and into far western Colorado for July with above normal temperatures favored across the entire western United States through September.
July 2018 Temperature and Precipitation Outlooks
Three Month Temperature and Precipitation Outlooks
(Including the months of July, August and September)
What is the Monsoon?
The North American Monsoon Season typically begins towards the end of July and continues through early September. It is associated with a long duration weather pattern shift as the subtropical ridge of high pressure amplifies and moves to our east. This results in a shift in upper level winds with the flow turning to the south, allowing for moisture to be pulled northward from the Pacific Ocean and the Gulf of Mexico.
What is a Monsoon?
Even in the tropics, where the weather is warm year round, the march of the seasons has a profound influence on the rhythm of life. Rainy seasons, usually referred to as monsoons, alternate with dry seasons and each has its own distinct pattern of prevailing winds.
The term “monsoon” is derived from the Arabic word “mausim” which means season. Ancient traders sailing the Indian Ocean and Arabian Sea used it to describe a system of alternating winds that blow persistently from the northeast during the winter and from the opposite direction, the southwest, during the summer.
It is now well understood that seasonal reversals of wind direction occur because of temperature differences between the land and sea across all of the Tropics. There are many features in common to these summer monsoon circulations, but the most recognizable are the seasonal changes in rainfall patterns, both increases and decreases.
Why Predict a Monsoon?
Billions of people in the tropics and subtropics rely on the summer sun to draw rain clouds off the oceans and onto the continents. For centuries, people have sown and harvested crops, bred livestock, and planned outdoor activities such as construction projects or hunting expeditions according to a relatively well-defined set of calendar dates based on the arrival and departure of the monsoon rains.
In many countries the arrival of the summer monsoon rainfall is good news since it replenishes the waterways and provides a critical supply of water for agriculture and other economic concerns. However, occasionally the rains are excessive and can cause serious and life-threatening floods. At other times a weak monsoon can cause a drought to develop, leaving fields and waterways parched and dry. Since extreme weather conditions associated with monsoons, like floods and drought, occasionally wreak havoc on a region’s economy and people, monsoons throughout the world need to be accurately understood and predicted by weather and climate models, so that scientists can anticipate upswings and downswings in the monsoon and help societies plan accordingly.
Is there a North American Monsoon?
The circulation and rainfall patterns over the tropical and subtropical Americas and the adjacent oceans are dominated by seasonal monsoonal circulations. However, seasonal reversals of the wind are less pronounced over the Americas than in other parts of the world like Australia, India and Southeast Asia. The North American monsoonal circulation is characterized by distinct rainfall maxima over western Mexico and the Southwestern United States (Fig. 2) and by an accompanying upper-level anticyclone (indicated by “A”) over the higher terrain of northwestern Mexico. Heating over the mountains of Mexico and the western United States plays a major role in the development and evolution of the monsoon, in a manner similar to what is observed over the Tibetan Plateau and the Bolivian Altiplano. Rivers of air in the lower-troposphere, referred to as low-level jets, from the Gulf of Mexico and the Gulf of California bring moisture to the continent and play an important role in the daily cycle of precipitation (Fig. 3).
The North American Monsoon System is perhaps the least-understood of all of large-scale circulations patterns that affect the United States. What’s more, the regions that are most affected by the monsoon are among the most rapidly growing parts of both the United States and Mexico. The thunderstorms that are generated by the monsoon system can bring life-giving and beneficial rains, but can also be life-taking as they unleash violent flash floods, thousands of lightning strikes, crop-damaging hail, and walls of damaging winds and blowing dust.
As tropical storm BUD spins it’s way north in the Sea of Cortez it’s copious moisture is being drawn into the desert southwest by a large low-pressure trough originating in the Pacific northwest. The trough’s counter clockwise spin is drawing in BUD’s energy and up to 1.3″ precipitable water has been measured. When the disturbance moves into the San Juan later tonight and tomorrow we could see some good rains, lightning and flash flooding near the Durango burn areas. Might get ugly if all this activity works in syncronicity.
Some satellite photos and vorticity/ precipitation maps below.
A big world view of BUD in southern Sea of Cortez about noon MST with the low pressure trough drawing it’s moisture into the desert SW.
Precip map at 12Z today
Vorticity (measured instability of a vertical air mass), showing the low dropping down from the Pacific NW into southern Cal and the Great Basin today at 12Z. See BUD (yellow & red) at the bottom over southern Baja California.
Infrared satellite photo at 12Z today.
I didn’t send out a climate outlook at the beginning of June, basically because nothing had changed. La Nina is dead (no grieving for that no-winter bitch from me). Snowpack and mud season are gone except up near Wyoming way. The CPC were stuck on hot and mostly dry for their outlook. http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/page2.gif
Well there are now some developments. Tropical Storm Bud is spinning south of the Baja and heading north. https://www.nhc.noaa.gov/cyclones/?epac The latest forecast brings deep moisture from this system into Arizona and vicinity by mid week next. http://www.cpc.ncep.noaa.gov/products/predictions/610day/610prcp.new.gif
Could this be the beginning of the monsoon? Of course the onset of the monsoon is a dangerous time with lightning often preceding the rains. Let’s hope we get some nice female rains.
Do whatever you as Masters need to do to make it happen. Ellen and I will deploy our garden prayer flags.
Joe riding monsoon season in Grand Junction
National Weather Service forecaster Jeff Colton called for several more dry, hot days across Southwest Colorado. The soonest possibility for rain will be Wednesday. Summer monsoons typically begin mid-July but could begin sooner this summer, perhaps the last week of June, based on La Niña weather patterns, he said.
Almost every tract of land in the contiguous United States was warmer than normal in May, helping to break a Dust Bowl-era record.
The month’s average temperature 0f 65.4 degrees swept by the previous high mark of 64.7 degrees set in 1934. Temperatures were more than 5 degrees above normal, according to the National Oceanic and Atmospheric Administration, which published a May U.S. climate assessment Wednesday.
The 1934 record was impressive, enduring for decades even as the climate has warmed because of increasing greenhouse gases in the atmosphere. One of the main reasons May 1934 was so hot was because it was so dry, posting the least precipitation for the month on record. When the land surface is dry, it heats up faster.
A combination of drought and farming practices had left fields bare of vegetation in 1934, resulting in “an estimated 35 million acres of formerly cultivated land had been rendered useless for farming,” according to History.com.
The parched conditions were so severe that on May 11 “a massive dust storm two miles high traveled 2,000 miles to the East Coast, blotting out monuments such as the Statue of Liberty and the U.S. Capitol,” History.com wrote.
In May 2018, temperatures soared to record levels even without as much help from dry soils. Precipitation was a hair above normal averaged over the nation. Maryland, hit by major floods in Frederick and Ellicott City, had its wettest May on record. So did Florida. Asheville, N.C., posted 14.68 inches of rain, its wettest month in history.