This rain won't clean your car off!

We've received several reports from social media this morning of sprinkles on cars and other outdoor objects that leave behind a residue, or dust, after evaporating. In fact, I had noticed the same thing on my windshield yesterday and assumed pollen, but didn't look closely. The pictures received though we definitely NOT pollen. It was dirt.

Morning sprinkles evaporated, leaving these dust spots on Carissa H.'s car (@rissa424)

A couple of thoughts immediately came to mind. First (and this one seemed less plausible than the second) was dust/dirt from Arkansas that was sucked up by tornadoes on Sunday and deposited downstream. I had heard of such a thing happening, but the timing (2 days later) and wind patterns didn't quite make sense. The second option was dust from the plains carried east on upper level winds. Knowing there was a massive trough over the middle of the country and a strong jet stream blowing from west to east across our area, I knew that option was more plausible.

Sure enough, after a little digging and checking in with the NWS to get their opinion, I'm fairly confident that it is indeed dust from the plains. For the past few days, strong and gusty north wind has prompted dust storms across the central and southern plains. In fact, the NWS watch/warning map below shows Wind Advisories and High Wind/Dust Storm Warnings in effect right now across the plains.

Then, I got a text from a family member who happens to be on the interstate in the TX panhandle describing vicious wind and "raining mud!" Sure enough, dust storms were in progress and light rain was dropping the dirt back to earth! Dust storms are known to eject fine dust particles thousands of feet into the air where they are carried by the currents downstream.  Below is the current upper level (about 35,000') jet stream courtesy of an awesome animated web tool called the "Wind Map."  The large L is the low pressure trough that the jetstream wind is flowing around. Key points are labelled.

So you can see that as the dust is picked up and ejected into the upper levels of the atmosphere, it gets carried downstream and deposited or rained out of the atmosphere! The light rain falling this afternoon is not going to be good at washing pollen off your car, but instead could result in a trip to the car wash thanks to strong wind and plains dust that is transported all the way to Tennessee!

Erik Proseus
MWN Meteorologist

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Weather worth writing home about!

What a fabulous spring week we have in store across the Mid-South! In the wake of a cold front over the weekend that brought storms Saturday night and cloudy and very cool weather on Sunday, high pressure is building in. This high will hold on for several days, making for some gorgeous days! High pressure is moving in not just at the surface, but well up into the atmosphere as well. This ridge of high pressure will help warm things up considerably over the central U.S. and then into the eastern portion of the country as we head into the week. In fact, highs in the lower 60s today will increase by about 10 degrees for Tuesday and several more degrees on Wednesday, putting the Mid-South near it's first 80 degree days of the year to end the week!

The map above shows the jet stream level (about 34,000 feet) forecast for Wednesday evening, when the ridge of high pressure is directly overhead. If you look upstream though (to the west), you'll notice a large trough of low pressure over the west coast. This is what meteorologists refer to as a "highly-amplified pattern" - featuring large "peaks and valleys" in the upper levels. Under the large peaks, like the one over the Mid-South, warm and tranquil weather is usually found, while under and just ahead of the valleys, like on the west coast, stormy and cooler weather is typically present. The jet stream is indicated by the white arrow over the brighter colors, which are higher wind speeds.

As that large trough approaches the region, it will bring our next round of unsettled weather. Computer models tend to agree that the magnitude of that trough will weaken as it moves east, but we're still looking for a frontal passage and accompanying precipitation sometime this Easter weekend, probably on Saturday.

MemphisWeather.net will continue to watch the scenario unfold and the forecast will be updated with the latest expected trends. In the meantime, enjoy the beautiful weather! Before you know it, we'll be wishing we had the 70s back again!

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