These maps break down May tornadoes based on where they begin.

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In your average year, May is the expected peak of tornado activity. That’s of course not always the case, but the month has had over 4,000 more tornadoes than April since 1950 and it has seen almost 2,000 more touch down than June.

By May, a very noticeable move away from the cool-season home of tornadoes around the Gulf Coast and in parts of the Southeast is seen as the tornado zone lifts north and west into summer.  The heart of the classical tornado alley is shaded in lots of red during the month, and again in June.

Where tornadoes form: October, November, December, January, February, March, April

May usually brings about 260-280 tornadoes to the country, depending on how long and when your averaging period is.  Through 2014, 12,864 tornadoes have been recorded in May across the country going back to 1950.  The long-term average, skewed by early years with under-reporting, is 198 tornadoes per May.

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After what is looking like a near normal tornado count for April, May will be starting off on a quiet note. The tornado hiatus is not expected to last too long, with the tornado potential picking up a bit around midweek next week.

1-3 Day
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Thursday

No tornadoes expected.

Friday

No tornadoes expected. Maybe a landspout in Colorado? Flow’s weak.

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Much quieter in the Southeast compared to this day four years ago, which was the Super Outbreak of 2011. “Quiet” will be the theme for most of the next seven days, with an upper-level ridge shutting down storm activity over the central U.S. while a trough in the Great Lakes and Northeast keeps cool, stable air over the eastern U.S.

Also, a quick reminder that the Day 1 forecast is active from the time of the post, not for the entire day. Tornadoes that occurred before the time of the post are not included in the forecast tornado count.

1-3 Day
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Monday

Eastern Texas, Louisiana — TORNADO RANGE: 2-6 — CONFIDENCE: Normal
Expected Tornado Hotspot: Eastern Texas
Pros: Great directional shear, good mid-to-upper level speed shear, low to moderate instability, good upper-level forcing.
Cons: Weak speed shear in the low-levels, unidirectional flow in the mid-to-upper levels, potential issues with weak lapse rates around 850mb.

Tuesday

Central and eastern Gulf of Mexico — TORNADO RANGE: 2-5 — CONFIDENCE: Normal
Expected Tornado Hotspot: Central Gulf Coast
Pros: Good directional shear, good mid-to-upper level speed shear, decent upper-level forcing along the central Gulf Coast.
Cons: Low instability for most, weak speed shear in the low-levels, unidirectional flow in the mid-to-upper levels, potential for slightly backing winds in the mid-levels, poor mid-to-upper level lapse rates and poor upper-level forcing in Florida.

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Tornado highlights covering the week of April 19-25, and a brief look ahead.

A tornado mostly wrapped in rain near Victoria, Kansas on April 24. (Travis Farncomb via Twitter)

A tornado mostly wrapped in rain near Victoria, Kansas on April 24. (Travis Farncombe via Twitter)

Despite lacking a huge outbreak — of course the Ill. EF4 happened on a big day — April 2015 has continued to produce tornadoes on the regular.

Last week was the most active of the year, and this week is already off to another active beginning as the final wave in the current train of storms moves east across the country.

After today and perhaps tomorrow, we may need to wait a little while to get things going again.

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The tornado potential spikes Friday and Saturday across the South, with another period of somewhat-favorable conditions in the southern Plains early next week. Threats start to diminish heading into midweek as upper-level ridging takes over in the Plains and troughing sets up over the eastern U.S.

The abridged-because-suddenly-vehicle-repairs edition. I swear, things are conspiring against me and having free time on Mondays and Thursday this year.

1-3 Day
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Thursday

Central High Plains — TORNADO RANGE: 0-2 — CONFIDENCE: High
Expected Tornado Hotspot: None

Central Texas — TORNADO RANGE: 1-4 — CONFIDENCE: Normal
Expected Tornado Hotspot: None

Friday

Central and southeastern Plains, southern Miss. Valley — TORNADO RANGE: 7-16 — CONFIDENCE: Normal
Expected Tornado Hotspot: Eastern Plains

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by Katie Wheatley, Brendan Heberton, and Ian Livingston


View a larger version of this map here.

A question we’re often asked is, “which month has the most tornadoes in my county?” Now we’ve got some answers.

While tornado season is typically thought of as spring, because a majority of them occur from April through June, twisters can and do happen throughout the year.

In fact, as you’ll see above and in more detail below, every month is represented when it comes to peak tornado activity when plotted on a U.S. county map. In many instances, a pattern can be seen, especially as the heart of tornado season comes and goes across the central United States.

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So the last Tornado Threat forecast busted way low with tornado numbers from that little cut-off low that could. Probably my worst threat forecast to date. Let’s try to turn that around with this update.

It’s abridged today because I am in desperate need of sleep. Thursday should be a regular update.

1-3 Day
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Tuesday

No tornadoes expected.

Wednesday

Southern Plains, Arkansas, Louisiana — TORNADO RANGE: 4-9 — CONFIDENCE: Normal
Expected Tornado Hotspot: Southern Oklahoma, northern Texas

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Tornado highlights covering the week of April 12-18, and a brief look ahead.

A tornado southeast of Goodland, Kansas on April 17. (Chip Redmond via Twitter)

A tornado southeast of Goodland, Kansas on April 17. (Chip Redmond via Twitter)

April continues to do what April does, deliver numerous severe thunderstorms to the country.

The week ending April 18 featured tornado reports on all but two days. Still, no day during the week is likely to be long-remembered when it comes to twisters. By and large, the story there was “quick and weak” when it comes to touchdowns.

A big and slow-moving cut off low was the primary driver of severe weather. It’s finally rejoining the flow as we start this week off.  A corresponding severe weather risk pushes toward the East Coast with it. More episodes of storms are likely this week, with caveats.

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Still stuck in a fairly quiet pattern despite daily tornado threats… that’s what a stubborn cut-off low will get you on most occasions. The start of next week has the lowest potential for tornadoes, but things pick up again briefly around the middle of next week.

1-3 Day
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Thursday

Central and southern High Plains, Texas, southern Louisiana — TORNADO RANGE: 1-4 — CONFIDENCE: Normal
Expected Tornado Hotspot: Central High Plains
Pros: Good directional shear, decent/good speed shear, low to moderate instability, good upper-level forcing in the High Plains.
Cons: Morning and afternoon clouds and showers contaminating the atmosphere, potential high LCL issues in the southern High Plains, no notable upper-level forcing in the southern parts of the risk area.

Friday

Central and southern Plains, Louisiana — TORNADO RANGE: 1-4 — CONFIDENCE: Normal
Expected Tornado Hotspot: West-central Plains, central Texas
Pros: Good directional shear, low to moderate instability, good upper-level forcing in the central Plains.
Cons: Potential veer-back-veer wind profiles in the central Plains, weak speed shear in the eastern parts of the risk area, no notable upper-level forcing in the southern parts of the risk area.

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An EF-4 churns near Rozel, Kansas on May 18, 2013. (Jeremy Perez via Flickr)

An EF4 tornado churns near Rozel, Kansas on May 18, 2013. (Jeremy Perez via Flickr)

It’s the age of the wedge tornado. At least in reports.

The continued popularization of storm chasing, and weather as a whole, has brought certain geek words out front in recent times. Often, they are incorrectly used.

True wedge tornadoes — appearing at least as wide as they are tall — make up only a fraction of all types and shapes. Despite the seeming appeal to “run to wedge,” other terminology is largely intuitive and it helps everyone be better informed.

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