Category: Tropical weather

Here’s an afternoon update based upon the latest model guidance for the tropical system, Invest 93L, now located in the southern Gulf of Mexico. A hurricane hunter is investigating the system this afternoon, and it may be upgraded into a depression or storm later today.

It’s best not to think of this system as a classical tropical storm or hurricane, but rather, as my colleague Matt Lanza puts it, “an atmospheric river” of moisture flowing from the south into the United States. In other words, we’re dealing with something that’s going to bring a lot of rain to someone along the Gulf of Mexico coast. Consider the following forecast, from the European model, for precipitable water values on Wednesday night.

Precipitable water values for Wednesday night. (Ryan Maue/Twitter)

Any value above 2 inches of precipitable watyer is quite high, and you can see that although the center of this storm is near the Texas coast, it is funneling a massive amount of moisture from the Gulf of Mexico into Louisiana. That spells a heavy rainfall event.

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The heat is on for Houston. Sunday’s official high temperature reached 96 degrees, and we’re going to have a couple of more days in the mid-90s, with isolated to scattered showers and thunderstorms, before our weather may change significantly by Wednesday due to a tropical system. Or not. Here’s the latest on what we know about Invest 93L, the system moving toward the southern Gulf of Mexico.

Organization

The storm remains very large and disorganized, producing fairly heavy rains on its eastern side. The best estimate as of Monday morning is that its center is now moving across the northern tip of the Yucatan Peninsula, and will emerge into the southern Gulf of Mexico later today.

“X” denotes approximate center of circulation. (NOAA)

A hurricane hunter is scheduled to investigate the system this afternoon to better characterize its organization, and the National Hurricane Center still rates it as a 90 percent chance of becoming a tropical depression or storm this week.. But as we’ve been suggesting, it’s unlikely to find overly favorable conditions to strengthen in the Gulf of Mexico, so the primary threat from the system will be heavy rains.

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Good morning. Houston has clearly moved into a summer-like pattern of weather, and our weather won’t change much over the next several days. And we probably won’t change too much next week, unless an area of disturbed weather in the tropics migrates to the north. We’ll discuss that possibility below.

Today

There may be a few spotty showers across central and eastern portions of Houston today, but for the most part a building ridge of high pressure should shut rain chances down for the area. Look for mostly sunny skies with high temperatures in the low 90s.

Friday and Saturday

Warm and sunny, with highs in the low- to mid-90s, and overnight lows around 80 degrees.

Sunday through Tuesday

The high pressure that will largely dominate our weather from now through Saturday or so may slip away to the north by Sunday, opening up the possibility of some isolated or scattered showers during the daytime. Temperatures will be warm when it’s not raining, with highs likely rising into the mid-90s. That will be new for us, as the warmest it’s gotten so far this year has been 93 degrees (twice). Read More…

Summer—steamy, humid, and hot—is finally here. Houston certainly enjoyed a nice reprieve last week, as Bush Intercontinental Airport recorded a streak of four mornings (Thursday through Sunday) of low temperatures ranging from 67 to 69 degrees. The monthly average temperature so far is about 2 degrees below normal.

But by Sunday afternoon it “felt” like summer outside, and that’s how conditions will remain for about the next three months, and of course we’re only going to get warmer as we get deeper into July and August.

Today

After several mostly sunny days, clouds will return to the forecast area today, and this will herald a pretty decent chance of rain. Moisture levels are higher to the east of Houston, so rain chances will be considerably higher to the east of Interstate 45 than to the west. So look for scattered showers for the eastern half of Houston, and fairly isolated showers to the west. Accumulations for the most part will be low, perhaps a tenth of an inch of rain or two. Highs today should be around 90 degrees, with muggy overnight lows in the upper 70s.

Tuesday

A similar day to Monday, although with a bit less moisture I’d expect a bit less rainfall coverage for the area. Humidity levels remain very high, with temperatures around 90 degrees and lows in the upper 70s.

Don’t expect too much rain this week, as the 7-day NOAA forecast indicates. (Weather Bell)

Wednesday through Friday

Moisture levels will fall off some, which will leave us in a summer-like pattern for the region. This means partly to mostly sunny skies, with a slight chance of afternoon showers as the sea breeze moves in. Look for highs in the low 90s, and overnight low temperatures in the mid-70s.

Saturday and Sunday

Moisture levels don’t look particularly high, but the upper-level pattern suggests that some storms may be possible. For now I’d feel comfortable saying there’s a 20 to 30 percent chance of storms for Houston, but most likely we’re going to see warm, partly sunny days.

Tropical note

We’re now about a dozen days into the Atlantic hurricane season. So far conditions have been calm, but forecast models are hinting at some development in the Caribbean Sea this weekend that may eventually move into the Gulf of Mexico. I say this not to alarm you, but because some people may share forecasts about this system that show something developing near Texas. I’m not ruling that out, but there are quite a few factors weighing against this happening right now, so I wouldn’t be overly concerned. We’ll watch it and let you know if there’s anything that matters.

Posted at 6:55am CT on Monday by Eric

We’ve had a number of really, really nice spring days in recent weeks. And expect us to get another one today. Let’s get to it.

Colorado State Hurricane Outlook

First, I want to just touch on a report released yesterday from the tropical weather research group at Colorado State University. The CSU team produces one of the most widely used and anticipated seasonal hurricane outlooks for the Atlantic. Their forecast for this year calls for below normal activity in the Atlantic basin.

They’re going with 11 storms, four hurricanes, and two major hurricanes for the 2017 season. Recall that last year saw 15 named storms, seven hurricanes, and four major (Category 3 or stronger) hurricanes. Last year’s CSU April forecast called for 12/5/2 in that order. This year will be challenging with risks of another El Nino developing and some uncertainty as to what the ocean temperature profiles in the Atlantic Ocean will look like during the peak of the season. We’ve been in an active period of Atlantic hurricanes since 1995, and there are questions as to how much longer that will last. They will monitor these variables and update their forecast in early June.

Klotzbach’s team also helps put together landfall probabilities by county. You can examine the details yourself, but in the interest of ease, they give a 3.7% probability of one or more named storms making landfall in Galveston County, compared to a 4.3% chance historically in any given year. Texas as a whole has a 38.2% chance using their methodology, compared to a climatological average of 43.3% that a named storm will make landfall. In a nutshell: Slightly lower than normal odds for a landfall than in an average season.

Use hurricane outlooks with caution

There’s a BIG caveat here. Remember, seasonal hurricane outlooks are primarily an academic exercise. Operationally and for most of you, they don’t matter. If we have two storms in the Atlantic all season and one is category 4 that plows into Galveston, it was a below normal season but an awfully bad one for a lot of people. They’ve become a curiosity we need to share, and the group at Colorado State does really good and ultimately important research. But you should ignore this forecast and go ahead and think about preparing for hurricane season anyway. 

(Space City Weather is sponsored this month by The Mole, a Jonathon Price novel.) Read More…