The rainfall that fell across the area late last week helped give a nice boost the Edwards Aquifer, and the city of San Marcos starting tomorrow (Friday, September 21st) will be back in stage 2 water restrictions.  The official release is posted at the bottom of the page.

Even though the recent rains have helped the Aquifer, they hardly put a dent in the current drought in our area.  Below is the current US Drought Monitor Map for the week ending 9/18/2012 and issued this morning.  I have circled in blue areas that have gotten worse in the state in the past week, and it green are the areas that have gotten better.  Our area has not seen any change since last week, even with the rains.

Here is the official information from the City of San Marcos.

San Marcos to Return to Stage 2 Drought Rules Friday

 San Marcos returns to Stage 2 drought response rules on Friday, Sept. 21, as recent rains helped aquifer levels rise above the trigger levels that have kept much of the Edwards Aquifer region under Stage 3 restrictions since mid-August.

 Tom Taggart, Executive Director of Public Services, issued an order on Wednesday to terminate Stage 3 restrictions and return to Stage 2 effective at noon on Friday. San Marcos has been under Stage 3 since August 20 when the aquifer dropped to 637.8 feet and the ten day average declined below 640 feet above mean sea level, the trigger level for Stage 3.

 Stage 2 rules in San Marcos restrict use of sprinklers and automatic sprinkler irrigation systems to one day per week on a designated weekday determined by address.  Using soaker hoses, drip irrigation and hand watering is allowed on any day before 10 a.m. or after 8 p.m. 

 The rules also limit at-home car washing to one day per week, prohibit filling new swimming pools, prohibit using outdoor decorative water features, and prohibit washing paved surfaces.

 Stage 2 rules are available on the City of San Marcos website at www.sanmarcostx.gov/drought.  For more information please contact Jan Klein, Conservation Coordinator, at 512.393.8310.  To report watering violations, please call the Water Conservation Hotline at 393.8360.

 Stage 2 in the San Antonio Pool of the Edwards Aquifer is implemented when the ten day average at the Bexar County J-17 index well falls below 650 feet or rises above the Stage 3 level of 640 feet above mean sea level (msl).  On Wednesday, the 10 day rolling average was at 643.1 feet and the daily reading was 648.0 feet above sea level.

 The Edwards Aquifer Authority requires permit holders in the San Antonio pool of the aquifer to reduce pumping by 30% in Stage 2.

 In 2011, San Marcos and the Edwards region were under drought restrictions for most of the year through February of 2012.   

 This year, San Marcos activated Stage 1 watering restrictions on April 23, Stage 2 on May 7, and Stage 3 on August 20 as the aquifer serving more than 2 million people in the San Antonio region experienced a steep decline this summer.

 The City of San Marcos receives 85% of its water supply from surface water from Canyon Lake and 15% from the aquifer.

Along with the good rainfall we saw this week, temps also fell to levels not seen since the middle of May.  What I found crazy about this is we hit only 72 yesterday, the last time our high was in this neighborhood was May 15th.  What is crazy about it, is we hit 74 that day in May, after a 2 day rain event that dropped temps.  Just like the 2 day rain event we had this week, both the one in May that dropped the temps and the one this week, both events recorded 1.21″ of rainfall at Camp Mabry.

Below are the two day almanac readings at Camp Mabry for the May and September events.

All of this means little to n0thing as far as a forecast goes for the next few weeks, but I thought it was a very interesting coincidence  But notice the forecast highs/lows for the next 7 days vs. the 7 days after the mid-May event.

Below I have graphed the recorded high and low temps, with forecast high and low temps from May 1st through the end of our 7 day forecast (Sept 29).  Click on the image for a bigger version.

We have a nice little frontal boundary coming our way for this upcoming weekend.  It will be nice to finally not have crazy 100 degree heat finally.  I am already going to count tomorrow, as the 9th day in a row we have had 100 degree heat.  Friday will make our 35th day we have hit 100 or above this year, which is impressive.  But consider that last year we had 80 days of 100 degree heat through today (or tomorrow).  Last year we had a similar cold front that brought heat relief , gusty winds, and no rain.  Now this weekend we may see a few showers along the front as it blasts through, but in general winds and more seasonal temps are the end product.  For today, the normal high temp is 93, and this afternoon tied the record at 102.  I am quite excited about this cold front that will be arriving, but lets be honest, there isn’t much cold to this front.  For most folks its not bringing good rainfall, and its not bringing really cool air.  It will help overnight lows fall about a half dozen degrees below normal, but daytime highs will be at normal behind the front.

Does this mean we can close the books on 100?  Check out the chart below, last year we broke a heat streak with a back to back of 1 below normal afternoon, and one normal afternoon, and then temps bounced back quickly.  Something to remember, after the 29th of last year the 100s were done for the rest of the year.  That date is only 3.5 weeks away!

**Update**  Here is the latest 10pm (11pm edt) update for TS Isaac.

It was 7 years to the date that we were keeping our eyes on a strengthening storm in the Gulf of Mexico just north of Key West, Florida.  Today, we are watching a tropical storm just south of Key West with a forecast track that is very similar to that of the very destructive Hurricane Katrina.  Both of the below images are from the 5pm August 26th advisories for both Katrina (2005) and Isaac (2012)

Now, I will note there are a lot of differences in the two storms, but for folks in Louisiana, Mississippi, and Alabama along the Gulf Coast must be thinking ‘not again’.  Exactly 7 years ago Katrina was a little more north than Isaac is today, and more importantly was already a Cat 2 hurricane with winds at 100 mph.  The forecast tracks for both storms head right over the very warm Loop Current in the Gulf.  This area usually promotes more rapid intensification of the storms, and with Katrina this proved very true.  In a 12 hour period from 10pm on August 27 to 10am on August 28, Katrina went from a low end Cat 3 Hurricane with winds at 115mph (Cat 3 is 111-129mph) to a strong Cat 5 with winds at 175 mph.  The official forecast for Isaac makes it into a strong Cat 2 at landfall, with a one or two models pushing it to near Cat 3 or major hurricane status before landfall.

Here is the latest 0z run of the tropical models for Isaac:

What is interesting to note is the official forecast track is the thin black line that makes landfall in Mississippi is the official forecast track.  According to this graphic most of the model guidance has Isaac going to the left (west) of the official track.  I will note that the European and Canadian models are still both right (east) of the official track.  Since there is still a decent spread in the model guidance by day 3 for this storm, the forecast fan does cover an area from Central Louisiana to the western portion of the Florida panhandle.  This is the same area that is under a Hurricane Warning.

Below is a wave height forecast for 10am on Tuesday morning.

This is not good news for folks in the northern Gulf, or along the Northern Gulf Coast as all that extra water has to go somewhere.

Now, I am not in the business of forecasting oil or gas prices, but it is interesting to note the location of where we have most of our oil interests in the Gulf of Mexico.

Thanks to colorado.edu for the image.

So far 2012 has been an interestingly wetter than normal year.  Although at times it might not seem like we are getting enough rainfall, as a whole this year has been a bit wetter than normal.  The outlook for the fall does favor the near normal to slightly wetter than normal patter as well.  Even with the much higher rainfall totals this year compared to last, our Lake Levels and Aquifer level seem to be very close to levels from last year.  I went back and collected the data through the month of August for this and the past 4 years (5 years in total).  Obviously this year’s numbers are through today, but I compared the numbers to the normal values for the end of August.  The numbers that are in black are near normal numbers, the numbers in green are above normal, and the numbers in red are below normal.  Notice that at both Austin locations and the San Antonio location we have received roughly 4-8″ more than normal rainfall.  When you compare that to last year at the end of the month of August, we were nearly 11-14″ below normal for rainfall.  You would think this would have a big boost to the Lake Levels and the Edwards Aquifer, but that is not the case.  In fact, Lake Travis, Buchanan, and the Aquifer are almost at the exact same levels as they were a year ago.  Now it is true that areas upstream from the Highland Lakes have not quite seen the rainfall that we have gotten here in Austin, and this might have something to do with it.  Rainfall has been much greater over the Edwards Aquifer recharge zone this year compared to last.

Here is something to consider when looking at the data, and it may prove the drought last year was even bigger than we thought.  Even with the nice bump in the rain bucket so far this year at all 3 locations I listed below, our 20 month (Jan 2011-Aug 2012) totals are well below normal.  Also, much of our area is still in a moderate drought as well.  Here is something else you may notice, in 2008 we had a very dry year as well, however because we had such a very wet 2007, our  lake levels and aquifer level were still around or above normal (but dropping).  What is scary is the norm seems to be not having a norm anymore.  Looking at rainfall levels, only 1 of the past 5 (6 if you include the unlisted 2007 data) had numbers near normal, 2010.  Other than that we have had well above normal rainfall 2 times (2012, 2007), and well below normal rainfall 3 times (2011, 2009, 2008).

Wow, what a difference a few days makes.  Late last week we were riding a nice 11 day streak of 100+ degree heat.  Then a big dip in the upper level patter, a weak cold front, and some rain came our way.  High temps stayed below 90 on Saturday at Camp Mabry after some early afternoon showers and thunderstorms brought more than an inch of rainfall.  Out at ABIA we did not receive as much rainfall in the afternoon, so high temps climbed into the low 90s.  However, yesterday evening and into the overnight hours mother nature played catch-up.  Some areas saw upwards of 3″ of additional rainfall last night. We officially set a record yesterday at the airport for rainfall for August 18th with 2.83″.  The CoCoRaHS observer network showed some really impressive totals from 7a Saturday to 7a Sunday morning.  The highest total coming in a few miles north of Georgetown at just shy of half a foot (5.82″)!   Below are the CoCoRaHS observer network 24 hour rainfall totals ending at 7am this morning.

The good news about this weekend’s rainfall is that we picked up nearly 1″ of rainfall around Lake Buchanan, and the rivers leading into the Highland Lakes saw many areas with 1″ or more of rainfall as well. This probably won’t make a big dent in our deficits at Lake Buchanan and Lake Travis, but should slow the decline down for a bit. Again, this is another big rain system that fell just east of the Highland Lakes.
Below are the 48hour (weekend) rainfall reports from the LCRA stations in the area. (click on them to enlarge)

We have made it over the halfway point in the month of August and some welcome changes are in store for the upcoming weekend.  August is typically one of our drier months, and this August so far has lived up to its reputation.  Officially we have picked up 0.03″ of rainfall at Camp Mabry (a little less than the thickness of a dime).  The good news is a somewhat early season weather shift in the jet will allow for better rain chances and some cooler weather this weekend.   Also, starting today the normal high temperature begins to fall, as yesterday it was 98 and today it is 97.  The chart below shows the normal highs for the entire month of August.  We start the month at 97, climb to 98 by the 2nd, and stay there until the 16th.  The 2nd half of the month starts to see the normal high drop by a few degrees.   I should note this doesn’t mean that we cant still see really hot temps.  In fact the 2 hottest temps ever recorded in Austin occurred when the normal high temperature was 96 or below.

The forecast calls for a moderation of temps at night as well over the next few days.  This month so far we have had a few nights were we almost recorded record high low temps.  Yes, records are kept for the warmest nights (as well as the coldest afternoon highs).  When I was looking at the data for August, I noticed that not only was 2011 crazy hot in the afternoons, but the nights were as well.  Last August we set 11 daily records for the warmest overnight lows, with the warmest being August 11, 2011, with a low of 82.   The warmest overnight low recorded in Austin occurred before any of us were around back on July 28, 1898 when the low only hit 85!!

Ok, a few more stats to quiz your friends on this weekend when you are out at the lake, or while sharing an umbrella during a shower…..

Excluding today, we have had

- 10 days in a row of 100+ degree heat

- 36 days in a row of 90+ degree heat

- 93 days in a row of 80+ degree heat

- 31 straight days with temps not falling below 70

Here are some other stats on the number of times we have seen high temps at or above a certain number

This evening showers and t-storms popped up along a remnant boundary across our area.  While temps pushed above 100 in many locations along the line, we also saw good low level moisture across the area.  In the Weather Center, we were actually watching the clouds building out west during the afternoon hours.  When the storms finally broke out, again, gusty winds were the main severe weather issue.  We did see a fair amount of lightning with some of these storms as well.  We did have a few wind reports of 50+ mph wind gusts in Blanco & Williamson County.  We also had reports of tree limbs down in parts of Williamson County.  Rainfall totals that were reported in and estimated by radar looked fairly impressive in areas that needed the rainfall today.  It also provided a nice drop in temps as reading went from the low 100s to the upper 70s.

Our big ridge is making its exit off to the west-northwest and allowed a weak mid level trough to slide through the area today.  The result was a nice little watering of the lawns for people in our eastern counties.  This afternoon a lot of people in Austin saw the dark clouds and a few of us even felt a few little sprinkles, but as a whole, the showers just gave us here in Travis and Williamson counties just a little heat relief.  Look below at the temperature graphs from Camp Mabry and ABIA, both saw about a 9-12 degree temp drop as the rain cooled air moved in this afternoon.

Looking at rainfall estimates from our VIPIR radar today, you can see that most of the area south and east of Austin and I-35 saw some rainfall today.

The heaviest of the rain fell between about 2p and 4p across our eastern counties and then started to weaken in the late afternoon hours.

The good news is over the next week it appears the big heat ridge that had been in control of our weather will stay far enough to the west to allow a few little ripples in the atmosphere that will allow us several slight chances of an afternoon shower.  Again the best chances will remain in our eastern counties.  The only bad news about this, is humidity should be a bit higher and more uncomfortable the next week.

As far as the tropics go, Florence has been weakening through the day today as she pushes west.  As of now, she is a weak tropical storm with winds at 40mph and is forecast to become a tropical depression by Monday.  Ernesto weakened a bit from last night into this morning, but has gotten a little better organized later today.  The storm has also slowed its forward speed down a bit.  Winds with the storm make is a moderate strength tropical storm.  Each forecast run that has come out continues to forecast Ernesto travel farther south.  The current forecast will keep the storm well away from the US mainland through the rest of the life of Ernesto.  Below is a plot of the latest forecast models for Ernesto.  The white line is the official track which lies to the north of the guidance (for right now).

***UPDATE***

Here is the 10pm update from the NHC with the new track for Ernesto.  The biggest change in this update is the forecast for Ernesto to become a weak Cat.1 hurricane at landfall near Belize Tuesday night.  Also the track appears to be shifted slightly south to reflect this evening’s guidance.  Also, the latest forecast does not re-intensify the storm into a Hurricane again when it re-enters the Bay of Campeche.

MARS LANDING TONIGHT!!!

As Jim Spencer Blogged about a few days ago (http://blogs.kxan.com/2012/08/03/the-coming-mars-landing-sky-show/)  the Curiosity Rover is getting set to make its landing on Mars just after midnight tonight our time (12:31am).  It will be quite an amazing event if successful.  The current speed of the craft is about 8,400 mph as it closes in on the red planet.  The landing will cap off a 36 week mission to Mars!!!  Remember that next time you’re stuck on a 3 hour flight somewhere  For more information on the mission you can go to the NASA site http://www.nasa.gov/mars   Curiosity, just like all of us has its own facebook page as well http://www.facebook.com/marscuriosity and you can follow on twitter too http://www.twitter.com/marscuriosity.  I would suggest checking the NASA/mars site for information and videos on this mission.

Just a week ago I blogged about how the tropics have been pretty quiet so far this year and this is typically the time it starts to pick up.  Sorry!  It was like mother nature heard me taunting her or something.  All of a sudden within a 42 hour period late this week 2 tropical storms formed in the Atlantic.  This is one of the earliest that we have ever seen 6 named storms in the Atlantic Basin.  The last time we saw 6 named storms this quickly was just a few years ago in the record year of 2005.  That year the 9th named storm formed on this day, it became our 4th hurricane of the season in 2005.  Statistically speaking we normally see the 6th named storm of the year in the Atlantic around the 8th day of September, so we are quite ahead of the curve so far this year.   Our Jim Spencer relayed an interesting fact too on the lack of major hurricanes in the United States.  It has been since Hurricane Wilma back in 2005 (2,476 days ago) that we had a major hurricane make landfall in the US.  Not a bad drought for us to be in, and hopefully one that will continue.  At this point the model guidance for Ernesto keeps it south of the US late this work week, and as a weaker hurricane, probably a cat. 1.

In the tropics we also have Tropical Storm Florence that was named earlier today.  Her forecast track does call for minor intensification before hitting an area less favorable for development and then begins to curve into a more sheared environment.  The shear that this system encounters should work to weaken her later this week and should keep her being no threat to land.

I found a few climatology maps on the National Hurricane Center’s website that show the formation spots of storms in the Atlantic for the first 10 days of August, and also the likely tracks of storms for the month of August.

Ernesto formed in an area very typical for storms in early August.  Florence formed in an area that is more typical on mid-August to mid-September when you see more of the long track storms.

The latest hurricane model forecast run has the model tracks a little tighter together with landfall occurring sometime Tuesday night into Wednesday morning between the Yucatan Peninsula and Belize.  You can see them below on the image from the UCAR/NCAR website.