A soggy morning commute for most of the Houston area

We got through most of last night without any issues in Houston. Storms lined up well southwest of Houston near Matagorda Bay after midnight and have arrived across most of the metro area early this morning.

Radar at 5:40 AM shows widespread moderate to heavy rainfall across the Houston area. All this is moving slowly north and east and will be with us most of the morning. (RadarScope)

Radar as of 5:40 AM shows moderate to heavy rainfall across most of the area (with the exception of Freeport and north of The Woodlands). But everyone should see at least some rain through the morning.

As the day progresses, this rain will taper off or become more scattered in nature generally north and west of US-59/I-69. But heavy rain should continue into this afternoon generally south and east of there. A Flash Flood Watch remains hoisted for most of the area. We also have most areas south and east of US-59 in a “high risk” for flash flooding from the Weather Prediction Center today.

The Weather Prediction Center arm of NOAA has issued a “high” risk for flash flooding today for the southeast part of the area. (WPC/NOAA)

The WPC doesn’t hand out high risks easily, so that speaks to this system’s potential. A quick reminder from us: Please use caution when out and about today. It would be good to limit travel when you can on days like this, but if you are commuting or have to be heading out somewhere, be very careful and never drive through flooded roadways.

Total rainfall through this evening is expected to be on the order of 1 to 3 inches north and west of US-59. Some folks, particularly up in far northern regions (Conroe, Navasota, Cleveland to suggest a few) may see a bit less. The trouble spots are expected south and east of US-59. We expect 3 to 6 inches on average south and east of there, but some places will see higher amounts on the order of 6 to 10 inches or even a bit more.

Through this evening, rainfall amounts will average 1-3″ northwest of Houston and 3-6″ southeast of Houston, with higher amounts likely near the coast and bays. (NWS Houston via Weather Bell)

There are still some uncertainties with how this will exactly play out, but in general this will work for today as a forecast. This outcome would likely cause a good deal of street flooding in parts of southeast Harris, Galveston, Brazoria, and Chambers Counties. Bayou or creek flooding is also possible, especially along Clear Creek or perhaps some of the bayous in southeast Harris County.

The bottom line today: Flash flooding, particularly street flooding is likely in areas south and east of downtown Houston at times today, especially through early afternoon. Some more serious street or even creek and bayou flooding is also possible in a few places, depending on exactly how much rain falls and how quickly it does. Rain should taper off a bit, or at least become more infrequent toward mid-afternoon.

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Another chance for storms before a quieter weekend

For parts of Houston, yesterday was a dry sandwich on rain.

Rainfall was prevalent both north and south of Houston, but not so much in town. (Harris County Flood Control)

How’s that, Matt? Well, from the map above, you can see The Woodlands had just shy of an inch of rain in spots from morning storms. Grimes County even checked in with over 2.5 inches near Navasota. Other locations from northwest Harris into Montgomery Counties also got measurable rain. Then, south of Houston, afternoon storms deposited over 2 inches near Hobby Airport and over an inch down toward Pearland, with some more rain in other spots. Inside Houston, it was mostly dry. The east side saw some showers, but rains were mostly limited for the Inner Loop and north and west of town. We will take another swing at some rain chances today.

Today

Radar is quiet around the Houston area this morning, with just a few dying showers to our south.

Radar is quiet around Houston, but there is a healthy cluster of storms west of Fort Worth and near Abilene. Those could impact places like Bryan or College Station by early afternoon. (College of DuPage)

The more impressive storms this morning are near Abilene and west of Fort Worth. Look for that cluster of storms to drop southeast through the morning, possibly arriving far northwest of Houston near College Station by early afternoon. At the same time, a new scattering of storms should develop in and around Houston after 12-1 PM or so. So, the bottom line today: Expect a mostly quiet morning, with scattered storms this afternoon. Those under the most persistent storms later today could see two to three inches of rain in a short time. But also like yesterday, some folks in the area won’t see any rain at all. Have an umbrella for later, just to be safe.

Before and outside of any storms, temperatures will top off within a degree or two of 90 by early this afternoon.

Weekend

We shouldn’t see much more than a passing shower or two in the area for Saturday and Sunday. Most of us will be dry the entire weekend. Look for partly to mostly sunny skies both Saturday and Sunday. Temperatures will begin to heat up a notch further, with low 90s likely during the day away from the coast and upper-80s in Galveston. Nighttime lows will generally be in the lower of middle 70s inland and mid- to upper-70s along the coast or bays.

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More of the same for Memorial Day Weekend

Yesterday ended up seeing a few more showers in the area than expected, with a couple locations picking up about a tenth to a quarter inch of rain. Otherwise, it was dry. This holiday weekend will continue to bring limited rain chances, lots of sun, and plenty of heat, as it should feel more like late June than late May. After today’s forecast, we discuss NOAA’s hurricane outlook, released on Thursday.

Friday through Monday

Each day this weekend should be similar: Daytimes will be partly to mostly sunny and nighttimes partly to mostly cloudy. While we won’t advertise rain, there could be a couple brief showers in the area, particularly Monday afternoon. You should comfortably go forward with outdoor plans this weekend though. As Eric has noted this week, just keep hydrated and take it easy in the heat.

It’s always good to review swimming tips now. Rip currents will likely be an issue at times this weekend. (NWS Houston)

Rip currents will also probably be an issue at times this week on the Gulf, so it’s a good idea to do a quick review of the swimming safety tips above and always swim near a lifeguard.

As far as temps go, we will have a “back to the 90s” weekend! Look for 90° each afternoon, give or take a couple degrees. Obviously, it will be cooler along the Gulf, but even there will see mid- or upper-80s. Mornings will begin in the low- to mid-70s in most spots. Those of you out on the water will see southeasterly winds around 15 mph, perhaps gusting to 20 mph at times, especially today and Monday.

Next week

Look for continued heat and humidity most of the week. Rain chances remain on the low side for now, but there are perhaps some signs of slightly elevated shower chances as early as Wednesday, as strong Southeast U.S. high pressure begins to break down. This will allow for disturbances to edge closer to Houston by later next week. We’ll see if that actually happens, but it’s what to watch for change.

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What the heck was up with last week’s hail in Houston?

Last week’s storm system was mostly about the heavy rain and flooding, as Eric summed up nicely here. But the story that I think was most fascinating, meteorologically, was the hailstorm that hit some parts of the Houston area on Thursday night. The National Weather Service Houston office collected over 20 hail reports from the event, more than half of which were golf ball size hail or larger.

https://twitter.com/VortexChasing/status/1126686637394518016

Houston doesn’t often get hail this big over this wide an area. So what happened here? Why did we have so much big hail last Thursday?

Houston doesn’t see a lot of hail

If you look at the map of annual average 1+ inch diameter hail days per year (this from 2003-2012), you’ll notice Houston is mostly on the outside looking in at significant hail reports.

Severe hail reports are most common from Missouri and Kansas into South Dakota. (NOAA)

Why is this the case? For one, thunderstorm updrafts are needed to allow for the water droplets that become hailstones to get above the freezing level. Houston is a warm place, and that freezing level is often too high and the storms not powerful enough to carry those droplets high enough for large hail to form. Our lower freezing levels occur in winter and spring, making hail more likely then. In fact, of the 62 hail reports of 2″ in diameter or larger in NOAA’s storm events database since 1950 in Harris County and adjacent counties, only 3 of those reports have occurred outside of January through May. The average hail maxima is also where it is because they simply get more powerful, supercell thunderstorms with violent updrafts in the Plains.

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