Evening weather update: Clouds & spotty showers

Update 5:30pm:

As expected this morning clouds and a few spotty showers are "retrograding" back toward Minnesota form the east.

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Twin Cities radar loop shows spotty elevated showers or "virga" pushing west.

GOES 1km visible satellite image shows clouds spreading into the metro and eastern Minnesota. "Streamlines" show surface wind direction.

Expect clouds and a few isolated spotty showers this evening. It will still be nice for most outdoor activities this evening, but the character of our weather has changed through tonight.

PH

*****

Welcome to day #4 of our picture perfect Minnesota weather, for now.

A ridge of high pressure has been protecting Minnesota from two storms this week. Under the ridge, dry sunny weather has blessed cloud weary Minnesotans. To the west, a storm in the Rockies spins away. To the east, an Ohio Valley storm is spinning showers as close as Madison.

Eastern system "retrogrades" westward:

The upper air pattern is "stuck" over North America this week. The eastern system which is spinning in the Ohio Valley is actually moving back toward the west, or "retrograding" toward Minnesota today.

The system is spinning a band of showers westward through Wisconsin. The showery band runs from Green Bay to Madison this morning, and it's moving back west toward Minnesota. One model, the NAM suggests it could reach far enough west to spread clouds and a few showers into eastern Minnesota including the Twin Cities by this evening.

Radar and satellite trends seem to support this notion. It looks like our "picture perfect" weather may briefly take a turn for the cloudier and wetter this evening.

"Omega Block" breaking down:

I talked earlier this week about the "Omega Block" upper air pattern that's brining nice weather to Minnesota this week. The ridge of sunny, milder weather is starting to break down today. The eastern & western storms will close the gap, and it looks like the western system will finally move in by Friday & Saturday bringing a few rounds of showers & T-Storms.

Models painting rain chances this weekend.

Unlike last weekend (why do storms always seem to fall on our weekends?) this system will feel a bit more summery. Temperatures should be milder and reach into the 70s between showers & T-Storm bouts this weekend.

Overall rainfall totals may fall in the .50" to 1" range for many locations this weekend.

It appears the bulk of the rain may favor Friday night and Saturday morning now...but timing of these systems is often not possible 2-3 days out.

Bottom line? Expect a few rounds of scattered showers & T-Storms this weekend, with some dry hours in between.

Here's my forecast breakdown through the weekend:

Today: Sunny start. High near 70. Clouds increase form the east late. Spotty showers possible this evening.

Thursday: Mostly sunny again. Mild High near 72.

Friday: Western storm pushes closer. Mixed sun & clouds. High near 72. Shower & T-Storm chances increase PM.

Saturday: Scattered showers & T-Storms. Muggy & milder in between storms. High near 74. Rainfall totals .50" to 1" in spots?

Sunday: Mixed sun & clouds with spotty storms. Several dry hours too. High near 74.

May sky show delights shuttle launch observers:

I posted recently about the ongoing sky show in the eastern sky during the month of May.

It seems conditions were perfect for viewing the show in the dawn sky as the Space Shuttle Endeavour prepared fro launch Monday.

"I witnessed the launch of Endeavour early Monday morning and was greeted by this scene when I arrived at NASA's VIP viewing site on Banana Creek," says photographer Tom Cocchiaro of the New Hampshire Astronomical Society. "It was as though the Gods were watching over Endeavour as it sat perched on the launch pad in the early twilight hours. Too cool for words."

You can check out more images from NASA at spaceweather.com.

Enjoy the beautiful start to today, but keep an eye to the east for late day clouds & possible showers.

PH