"Normal" temperatures and rain in the forecast

Another break from the heat is coming this week. This time, instead of temps dropping from 104° to 97° like last week, we'll actually drop back down to normal; the average normal high temperature this time of year is 93°. We haven't been that "cool" since the first week of June. Since then, we've had 27 consecutive days with high temps 95° or warmer and ten +100° days.

The hot high pressure in the upper atmosphere is finally breaking down and allowing a cool front to approach from the north. The Dallas area got a few showers on Sunday. We get our chance on Monday. Our exclusive FutureTrack shows scattered showers developing in the Houston area by late afternoon. With the front stalling out over southeast Texas there's rain in the forecast for Tuesday and Wednesday as well.

There's enough moisture in the air that some downpours are likely. I still expect the rain to be scattered, however, not widespread. So you might hear the thunder, but get no rain or not as much as your neighbors just down the street.

Hot as a firecracker this weekend!

Temperatures will top 100° this weekend, with the Heat Index a little closer to 105°.  Temperatures will stay in the 90s through the evening hours but it should drop into the mid 80s by the time fireworks are set off Saturday night.

Earlier this week the jet stream shifted and allowed a weak cool front to sag into Texas. That helped produce a few showers here and elsewhere across the state. This also allowed temps to drop off with highs "only" in the upper 90s for a couple of days. But that hot, high pressure is starting to build again. This will shut off the rain for the weekend and send our temps above the century mark.

However, another adjustment in the upper air pattern should allow another weak front to come near us early next week, producing a few more showers.

Heat relief coming Tuesday

Today's record high temperature also tied a record for the most consecutive days with high temps 100° or higher. We've had seven straight days of triple digit temps. That's one more than we had in 1980, considered the hottest summer in Houston.  And we still have two more months of summer ahead of us!

But after today, we're not expecting any more triple digit temps this week. And we're cautiously optimistic rain will return  as well.

Two weeks ago, Dave Ward asked me on-air how long the heat wave would last. I answered then that the high pressure in the upper atmosphere would start to break down Saturday, June 27 and within a few days temps should begin to fall along with some rain.

Now that the high is breaking down and moving westward, the upper air flow is allowing a weak cool front to push south across Texas. Pockets of heavy rain fell around Dallas early Monday. I expect some scattered showers around here tonight and Tuesday as the front sags south.  The real cool air will stay north of us, but we should get a bit of a break on the heat. We're forecasting highs in the mid 90s for the rest of the week!  That's still a little warmer than normal, but cooler than it has been.

So far this month, only .27" of rain has fallen at IAH, making this the fourth driest June on record.  But with rain in the forecast, that record probably won't stand.

There is some uncertainty in the forecast models about how much moisture will be around this weekend. We put in a slight 20% chance of rain for Friday and Saturday.  There is a possibility we might need to put more rain the forecast for the weekend.

If you follow "abc13weather" on Twitter then you knew about the changes to the forecast before everyone else. Twitter is a free, social networking service. In addition to posting daily weather updates, we will be using Twitter this year to tracking tropical weather systems. Sign up today!

Record heat keeps tropical weather away

Updated Monday morning: The tropical wave has dissipated. There are still a few residual showers but development is unlikely at this point.

Some more good news: an influx of moisture toward the end of the week could produce a few more showers around here. Data is still coming in from the morning forecast model runs. Check back for an update this afternoon.

Previous discussion follows:

Temperatures will hit record highs again today, for the fifth time in six days. Saturday's high was "only" 101° which was one degree below the record high. What concerns me is the records we're breaking were all set in 1980, the hottest summer on record.

The bubble of hot air is good for one thing: it keeps hurricanes away.  The tropical wave in the northwest Caribbean is moving into the southern Gulf of Mexico now.  Northerly wind shear has kept the storm from becoming organized, but there's still a slight possibility it could strengthen this week if/when the shear weakens. 

There's no consistency among the various forecast models. On Friday, most of the guidance showed the weak wave tracking northeast toward Florida once it cleared the Yucatan Channel.  Late Saturday, the models shifted 90° and showed the storm tracking toward northern Mexico or south Texas. Today, the models are split between both possible scenarios.

I still think the upper high over Texas will keep this storm away from us.  Is that a good thing? While you never wish for a hurricane, we do need the rain.

One thing is fairly constant: while most of the models show the wave developing into a tropical storm, none of them predict a hurricane.  Then again, intensity forecasts are not reliable.

New this year, I'll be posting tropical weather updates on Twitter, a free service.  Follow "abc13weather" on Twitter.

The heat goes on

The Heat Advisory has been extended.  We're still forecasting a high temperature of 100° on Friday with a heat index near 105°.

The National Weather Service issues a Heat Advisory when the heat index reaches 108° for two hours over two days. But once the Advisory is issued, the maximum heat index must drop below 105°.  That won't happen on Friday.

The upper air high pressure will shift westward this weekend and early next week.  This will give us a bit of a break on Saturday and Sunday; temperatures should only top out in the upper 90s this weekend. More importantly, this slight change in the jet stream pattern could allow a weak cool front to push into Texas bringing us some scattered showers on Monday and perhaps Tuesday. 

Honestly, we're not very confident on the timing and strength of the front so we might need to adjust the forecast over the next few days.

Unfortunately, the upper high looks like it will strengthen again by the middle of next week sending our temperatures back toward 100°.

Heat Advisory issued for the Houston area

The high temperature in Houston hit 104° Wednesday afternoon. That's a new record high for the day and it's also the hottest temperature ever recorded in the month of June.

The Heat Index topped 108° at 3 PM Wednesday afternoon. With temperatures expected to hit 103° again Thursday and with the Heat Index expected to be +108° again, the National Weather Service has issued a Heat Advisory for all of southeast Texas.

Our record heat is becoming dangerous. You are encouraged to limit the time you spend outdoors during the afternoon hours when the heat, humidity and sunshine are most intense. Keep in mind the temperature, and thus the heat index, are measured in the shade. Direct sunshine makes it feel another 10-15° hotter.

We expect temperatures to hit 100° again on Friday. But the high pressure in the upper atmosphere begins to weaken this weekend. By early next week, temperatures should drop back into the mid 90s and we've added a slight chance of rain to the forecast beginning Monday.

Until heavy rain returns, Burn Bans are in effect for several local counties.

Getting even hotter this week!

Record high temperatures are likely this week.  The first triple digit day of the season will be on Wednesday, but we're also forecasting highs 100° or warmer for Thursday and Friday.

Higher pressure in the upper atmosphere has shifted the jet stream to the northern part of the country. The air sinks under the high pressure which leaves us sunny and causes the atmosphere to warm. We started off with temps near 90° at the beginning of June. We first hit the mid 90s on Tuesday, June 9. Now we're headed toward 100° on Wednesday.

There's really nothing unusual about this pattern; it happens every summer. In fact, it was pretty warm here last June.  While we didn't hit 100°, the temperatures throughout June 2008 averaged 3.2° above normal. So far, this June is 3.0° warmer than normal.

Here's a list of the record highs for this week and the ABC13 forecast:

Tuesday, June 23

• Record High: 99 in 1990
• Forecast High: 99

Wednesday, June 24

• Record High: 99 in 1980

• Forecast High: 101

Thursday, June 25

• Record High: 100 in 1980
• Forecast High: 101

Friday, June 26

• Record High: 102 in 1980
• Forecast High: 100

Saturday, June 27

• Record High: 102 in 1980
• Forecast High: 99

The big question is: when will this heatwave break? We still think the upper high should break down a little this weekend, which should allow temps to begin to fall and perhaps allow precipitation to slide into the Houston area.

Burn bans in effect across southeast Texas

Several local counties have banned outdoor burning because of the dry conditions. Burn bans are in effect until further notice for the following local counties:

With no widespread, soaking showers in the forecast, I expect the burn bans to expand into several more counties.  In past years, even fireworks have been banned due to dry conditions.  Watch for updates as we get closer to the 4th of July.

Updated June 26, 2009

Another hot week ahead

As I mentioned on-air last week, it looks like the extremely hot weather will be around all this week too. 

High pressure in the upper atmosphere is parked right over south Texas. This has pushed the jet stream well to our north and left us high and dry.  Afternoon temperatures will continue to average 5-8 degrees warmer than normal all week. That's within 3-5 degrees of the record highs.

And despite all the humidity in the lower atmosphere, there's no chance of rain this week.

There is something good about this particular type of weather pattern. Should any little tropical wave try and drift into the Gulf of Mexico, it won't be tracking toward us. The same hot, high pressure also protects us from tropical weather systems. 

You want it cooler and perhaps a little wetter? Be careful what you wish for.

Air France Flight 447 weather conditions

High resolution satellite data shows the pilots of Air France 447 flew through some very intense thunderstorms which probably caused the plane to crash on June 1.

Meteorologist Tim Vasquez obtained the flight plan for AFR447 and used several different weather sources to map out the conditions along the flight. Read his report here.

Based on the position of the last transmission from the pilots before the distress messages were received, Tim's expert analysis indicates the plane was southwest of a cluster of severe thunderstorms and flying northeast. The cloud tops were 56,000-60,000 feet high, an indication of extreme instability with turbulent updrafts and downdrafts. These types of storms would most certainly produce a lot of lightning as well.

We still don't know for sure what brought down the plane. But the meteorological conditions Tim presents in his thorough analysis proves weather was most likely a factor.