Weather Change at this extent?

[m75]

Ok, so I am wondering if this is possible, and when it would happen if its possible.

Lets look at the a few rainy states of the U.S. Tennessee, Louisiana, Alabama, Florida, Mississippi, Washington, Oregon etc.

Is it every possible that weather change so drastically that those states would become completely dry, receiving little to no rainfall annually?

And the drier states. Arizona, Nevada, New Mexico, California, etc.

Could the drier states of the U.S start receiving 30-40 Inches of Rainfall?

Could this ever happen? And when will it?

-Thanks.

[dabize]

Ok, so I am wondering if this is possible, and when it would happen if its possible.

Lets look at the a few rainy states of the U.S. Tennessee, Louisiana, Alabama, Florida, Mississippi, Washington, Oregon etc.

Is it every possible that weather change so drastically that those states would become completely dry, receiving little to no rainfall annually?

And the drier states. Arizona, Nevada, New Mexico, California, etc.

Could the drier states of the U.S start receiving 30-40 Inches of Rainfall?

Could this ever happen? And when will it?

-Thanks.

The news reports tell us that those "drier" states are pretty dry right now. That's only going to get worse.

As for the "rainy" states, they may or may not get rainier, but the rain is likely to be concentrated in fewer events.

So droughts encompassing both dry and rainy states will become more frequent.

Starting right now.

[ORH_wxman]

Ok, so I am wondering if this is possible, and when it would happen if its possible.

Lets look at the a few rainy states of the U.S. Tennessee, Louisiana, Alabama, Florida, Mississippi, Washington, Oregon etc.

Is it every possible that weather change so drastically that those states would become completely dry, receiving little to no rainfall annually?

And the drier states. Arizona, Nevada, New Mexico, California, etc.

Could the drier states of the U.S start receiving 30-40 Inches of Rainfall?

Could this ever happen? And when will it?

-Thanks.

It would be nearly impossible for wet states like Oregon or on the gulf coast to become permanently dry in our current geographical setting and climate (even a much warmer climate)...they are too close to major moisture sources.

Drier states like in the southwest U.S. could definitely have some longer term droughts that we have yet to see in our modern history. Proxies have left evidence of some droughts spanning decades in the southwest U.S. back in the 12th century.

In more recent times, we have yet to match the droughts seen in the 1950s and the first decade of the 20th century in the southwest U.S. But I believe its possible we could equal or exceed the 1950s/early 1960s droughts over the next 5-10 years or so if the cyclical pattern of drought persists long enough before flipping back to a less dry pattern. The notable longer term dry periods seem to occur every 50-60 years in the southwest.

[nzucker]

All the evidence points to wet areas like the Northeast becoming wetter while arid regions like the Desert Southwest become drier. This is what climate modeling shows and has also been the trend the last 30 years.

[TerryM]

Matthew

In the pluvial period prior to the Younger Dryas there was plenty of water in the South West. Fishing camps and stone weirs are still extant from this period and can be spotted through a car window while driving in a now dry lake beds. This was a hot period with more ice melt than we're now experiencing. During the cold Younger Dryas things started drying out and continued to dry even as things warmed again.

The Anasazi built a fairly complex agriculture based civilization, with safeguards for expected periodic droughts, but in the 12th century the droughts became so extended that the culture collapsed.

I suppose all I'm saying is that as things warm, the precipitation patterns are going to become more chaotic than those we've experienced in the last 5k yrs - and things were chaotic enough in that period to cause the downfall of more than one civilization. I wouldn't worry about areas presently experiencing plentiful rainfall, but areas that depend on snow melt or that are already flirting with drought will be in trouble. In Nevada they tap water sources leftover from before Younger Dryas. The warm springs near Lake Mead are still flowing - but nothing has been replenishing them for over 10k yrs.

Terry

[ORH_wxman]

All the evidence points to wet areas like the Northeast becoming wetter while arid regions like the Desert Southwest become drier. This is what climate modeling shows and has also been the trend the last 30 years.

The northeast has definitely become wetter since their biggest dry period in the 1960s/early 1970s....really since we came out of that period, its been wet in the northeast for 30+ years now on a level that we haven't seen in the past 100+ years. The southwest, however, hasn't really seen anything exceptional...they are currently in a dry period the past 10 years or so...but its not of the magnitude and/or duration of the 1950s/early 60s or the 1900s.

The southwest could definitely see more severe droughts as we warm, but we have yet to see that trend occur.

[PhillipS]

Here is the

to a NOAA video showing the global rainfall patterns of the 20th century and the projected patterns for much of the 21st century. It also has a bit of explanation for the changes. As others have said, the general change will be for wet areas to get wetter and dry areas to get dryer.

[TerryM]

The northeast has definitely become wetter since their biggest dry period in the 1960s/early 1970s....really since we came out of that period, its been wet in the northeast for 30+ years now on a level that we haven't seen in the past 100+ years. The southwest, however, hasn't really seen anything exceptional...they are currently in a dry period the past 10 years or so...but its not of the magnitude and/or duration of the 1950s/early 60s or the 1900s.

The southwest could definitely see more severe droughts as we warm, but we have yet to see that trend occur.

Can you link to something showing worse droughts in the 50's and 60's or in the 1900's

The portions of the Southwest I lived in seemed much more concerned by more recent episodes, and I'm sure I came across some data from Texas last year that said they were experiencing a drought of much greater magnitude than anything in at least the last 100 yrs.

Terry

[ORH_wxman]

Can you link to something showing worse droughts in the 50's and 60's or in the 1900's

The portions of the Southwest I lived in seemed much more concerned by more recent episodes, and I'm sure I came across some data from Texas last year that said they were experiencing a drought of much greater magnitude than anything in at least the last 100 yrs.

Terry

The three versions of the Palmer drought index are most commonly used to assess drought conditions. You can read up on the Palmer Drought Index here.

http://www.ncdc.noaa.gov/oa/climate/research/prelim/drought/palmer.html

You can indeed see that Texas is experiencing one of their worst droughts in the past 100+ years on the Palmer Drought Severity Index (usually the optimal metric for longer term drought of 12 months or so)...you have to look carefully at the very right edge of the graph. You can also see very severe droughts in Texas on a more consistent basis in the 1950s, 1960s, ad then some earlier in the 20th century as well.

The Southwest US as a whole is also experiencing drought conditions. They are however not as severe as Texas by itself and they are not out of typical drought variation we normally see there verus past dry periods.

[TerryM]

Small sample size of course. but the dock where I kept my sailboat at lake Mead in the 60's has been miles from water for decades. The Colorado drainage is a small part of the Southwest, but so is Texas. Something I'd noticed in Nevada over time was that we'd get more of our yearly allocation in short bursts, which did little for the water table, but the flash floods did uncover archaeological and paleontological tidbits.

When St Thomas and the nearby Lost City rose again from the depths, many of us delighted in the opportunity to study and when I discovered a mammoth track way after a flash flood I didn't concern myself overly about the damage done down stream.

If Palmer's is the accepted index, don't they have a product covering the Southwest, rather than just Texas?

Terry

[ORH_wxman]

Small sample size of course. but the dock where I kept my sailboat at lake Mead in the 60's has been miles from water for decades. The Colorado drainage is a small part of the Southwest, but so is Texas. Something I'd noticed in Nevada over time was that we'd get more of our yearly allocation in short bursts, which did little for the water table, but the flash floods did uncover archaeological and paleontological tidbits.

When St Thomas and the nearby Lost City rose again from the depths, many of us delighted in the opportunity to study and when I discovered a mammoth track way after a flash flood I didn't concern myself overly about the damage done down stream.

If Palmer's is the accepted index, don't they have a product covering the Southwest, rather than just Texas?

Terry

Yes they do.

As for Lake Mead...the lake is drying up because we are taking much more water out of it than we did back in the 1960s in conjunction with a lot of drier years in the source region of the Colorado River in the late 1990s and most of the 2000s. Though they had a huge boost last year where the lake level rose quite a bit.

[tacoman25]

The news reports tell us that those "drier" states are pretty dry right now. That's only going to get worse.

As for the "rainy" states, they may or may not get rainier, but the rain is likely to be concentrated in fewer events.

So droughts encompassing both dry and rainy states will become more frequent.

Starting right now.

We have some posters saying wet areas will get wetter and dry areas drier...and then we have dabize saying dry areas will definitely get drier, but wet areas may or may not get wetter, yet droughts in these areas will become more frequent as well. So no matter where you live, look out, here come more droughts!

So who is right?

[TerryM]

I've been gone from the desert for almost a decade, but the flow of the Colorado is governed by Snow Melt upstream. They've been taking all they can get from Lake Mead since it first filled. When the lake dropped to levels not seen since it was being filled they initiated large releases from Lake Powell. Lake Powell had a good year in 2011, but 2012 is already back under previous levels.

From the Palmer chart for June & July, it seems the past 16 year period, with only 1 year showing positive is unique within the time frame & I'd assume that this year will only add to the record. Possibly a little un-natural variability?

Can you explain your statement ".but its not of the magnitude and/or duration of the 1950s/early 60s or the 1900s.", after looking at the last chart you provided?

None of the weather experienced anywhere on the planet is unaffected by AGW. As AGW increases more and more of the natural variability signal gets drowned out by the AGW Juggernaut.

Terry

Taco

Would looking at recent Palmer charts provide a hint at the direction we're going? I know that extensive flooding last year across all of Western Canada's prairies ruined the wheat crop, but have no idea if this was an aberration.

[tacoman25]

Taco

Would looking at recent Palmer charts provide a hint at the direction we're going? I know that extensive flooding last year across all of Western Canada's prairies ruined the wheat crop, but have no idea if this was an aberration.

I think what is most clear from the Palmer charts is that the Southwest goes through wetter cycles and drier cycles. We entered a drier cycle in the last decade.

[ORH_wxman]

I've been gone from the desert for almost a decade, but the flow of the Colorado is governed by Snow Melt upstream. They've been taking all they can get from Lake Mead since it first filled. When the lake dropped to levels not seen since it was being filled they initiated large releases from Lake Powell. Lake Powell had a good year in 2011, but 2012 is already back under previous levels.

From the Palmer chart for June & July, it seems the past 16 year period, with only 1 year showing positive is unique within the time frame & I'd assume that this year will only add to the record. Possibly a little un-natural variability?

Can you explain your statement ".but its not of the magnitude and/or duration of the 1950s/early 60s or the 1900s.", after looking at the last chart you provided?

None of the weather experienced anywhere on the planet is unaffected by AGW. As AGW increases more and more of the natural variability signal gets drowned out by the AGW Juggernaut.

Terry

We had 16 of 20 years in drought conditions from the mid 40s through the mid 60s in the southwest (that is duration). The 1900-1909 period saw 4 of the 6 worst droughts in the southwest including the worst one on record (that is magnitude)...therefore I wrote "magnitude and/or duration".

We have currently seen 13 of the last 16 years in drought condition in the southwest...so a little longer and we could match the mid-20th century. However, we will need to see a string of more severe droughts to match the early 1900s magnitude.

As for your quote "no weather experienced anywhere on the planet is unaffected by AGW"....well that's likly correct. However, that does not mean the weather has to get worse or more catastrophic. In fact, many events are relatively unchanged from AGW even if AGW is affecting the weather overall. AGW does not have to turn every weather event into a catastrophe as much as some would like to make it seem.

[TerryM]

I don't like the word catastrophe being used to describe the possible outcomes of AGW. I believe the term was coined by Frank Luntz - W's chief propagandist, as a derogatory term to describe climate realists.

Will some neighborhoods benefit from AGW - possibly, until things get a little worse and they no longer find rapid changes of this magnitude to their liking.

I can't think of anyone who would benefit long term, but I'll ask who you specifically had in mind.

Terry

[tacoman25]

I don't like the word catastrophe being used to describe the possible outcomes of AGW. I believe the term was coined by Frank Luntz - W's chief propagandist, as a derogatory term to describe climate realists.

James Hansen and many others pushing for more AGW awareness have used the term catastrophe or catastrophic in connection with global warming/climate change for many years.

In fact, Hansen's latest book was called Storms of My Grandchildren: The Truth About the Coming Climate Catastrophe and Our Last Chance to Save Humanity.