Updraft: May 8, 2012 Archive

Drought Buster: Wettest May in 8 years; Huge sunspot may trigger auroras

Posted at 7:34 AM on May 8, 2012 by Paul Huttner (5 Comments)
Filed under: Astronomy, Rainfall

Cool & showery Tuesday with a few T-Showers moving through today

- Latest Twin Cities radar animation tracking showers

Source: Twin Cities NWS

4.23" rainfall in the first week of May at MSP Airport

8 years since we've seen a May this wet

2" to 7"+ rainfall in the past week over a big chunk of southern Minnesota

6" - Lake Minnetonka is up nearly 6" from a week ago

2 feet - Rapid rises on Minnehaha Creek this week!

"Agricultural Drought" All but over for southern Minnesota

"Hydrologic Drought" Improving, but lakes still lower than 1 year ago

AR1476 - Biggest sunspot in years now facing "earthward"

M1 Class Flare erupted from AR 1476 Monday

Aurora Alert "Northern Lights" possible in the coming days

"It is best to read the weather forecast before we pray for rain." - More Maxims of Mark, Johnson, 1927

May Monsoon:

Somebody flipped the rainfall switch "on" this month.

In the past week, waves of torrential rains have dumped anywhere from 2" to 7"+ in southern Minnesota in a band from near Sioux Falls to Redwood Falls, Mankato and right into the Twin Cities metro.

Check out the impressive rainfall totals map below for the past week from the Twin Cities NWS.

Source: Twin Cities NWS

The 4.23" of rainfall looks like the wettest May in at least 8 years, and already exceeds the total monthly average for May in the first week!

It Takes a Flood:

Many weather quotes are attributed to Mark Twain. Some are hard to verify. But one that he may have said rings true.

"It takes a flood to end a drought."

The drought may not be totally over in Minnesota, but a flood of storms has left standing water in fields, filled up ponds and creeks, and noticeably raised lake levels in the past week.

Drought experts tell me there are two basic components to drought.

"Agricultural Drought" deals with moisture deficits in soils. Basically trees, native plants and crops begin to suffer when soil moisture drops for long periods. Cumulative precipitation deficits in many areas in Minnesota were running 5" to 10" below average going back to last summer.

Our wet spring has gone a long way toward recharging soil moisture. In fact, there is standing water in many fields and low spots in southern Minnesota these days.

The latest Minnesota Crop Report lists 71% of Minnesota topsoil with adequate soil moisture, and 18% with a surplus. That's 89% of the state with adequate to surplus topsoil moisture.

Source: United States Department of Agriculture

Translation? The "agricultural" part of the drought is basically history.

"Hydrologic Drought" deals with river & lakes and the pond in your back yard. Our May Monsoon-like deluge has Minnehaha Creek and others roaring back to life...with some 2'+ rises in the past few days.

Source: United States Geological Survey

It's a great time to enjoy Minnehaha Falls again!

Many lakes are still slow to respond. Lake Minnetonka was down 2 feet from last spring, but recent rains have raised the lake level almost 6" in the past week to 10 days.

Source: Minnehaha Creek Watershed District

That's good news for dock and boat owners, but we still have a ways to go on getting many of our lakes back to "normal" water levels.

What is a "Monsoon" anyway?

You hear the term "monsoon" tossed out sometimes when we get a heavy dose of rain.

Actually, the term has a much broader meaning, and does not refer to individual rain events. The phrase "monsoon season" is redundant and technically not accurate usage.

That's because the word "Monsoon" comes from the Arabic term "Mausim" which means "season." So saying "monsoon season" is like saying "season season."

A better way to say it is "Summer Monsoon."

Monsoon refers to the annual seasonal shift in mid-level winds in many parts of the world. The seasonal wind shift brings moisture from nearby oceans, and that triggers a "wet season" that brings critical rainfall to areas like India, parts of Africa and The Middle East.

Did you know there is also a monsoon in the southwest USA? It's technically called "The North American Monsoon" and it fuels spectacular summer thunderstorms in the Desert Southwest, especially in Arizona and New Mexico and Mexico.

Source: NWS Tucson, AZ

During my 9 years in Arizona I had the opportunity to talk with with Dr. Bob Maddox, Dr. Andrew Comrie and other monsoon experts in Tucson. There are basically two generally accepted criteria for a "monsoon climate."

1) A seasonal wind shift of at least 110 degrees in the prevailing mid-level winds (around 10,000 feet above ground)

2) At least 50% of average annual rainfall occurs during the monsoon

In Arizona and the southwest, mid level winds shift to "easterlys" and pump in moisture from the Gulf of Mexico. (sound familiar?)

Source: NWS Tucson, AZ

The summer monsoon in the Desert Southwest usually kicks in in early July and runs until September 30th.

Monsoon thunderstorms spawn severe weather, microbursts with damaging winds, massive dust storms (haboobs) and deadly flash floods.

Source: Tucson NWS

The monsoon is an incredibly visual phenomenon. If you ever get a chance to see it, you will witness some of the most spectacularly beautiful thunderstorms, lightning shows (and sunsets) on earth.

Aurora Watch: Biggest sunspot in years facing "earthward"

The biggest sunspot in years rounded the sun and is now facing earth. Sunspot AR1476 is about 62,000 miles across. That's about the size of 8 earths.

The ginormous sunspot is active, and blasted out an "M1 Class" solar flare Monday. The flare is streaming toward earth, and should arrive around 8am Wednesday (+ or - 7 hours) according to NOAA and spaceweather.com.

Source: NOAA/spaceweather.com

There is a decent chance for northern lights Tuesday and Wednesday night.

PH

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