Confusing 5-minute Weather Observations


Caveat Emptor.

Some NOAA websites are beginning to display ASOS (i.e., airport weather) observations every 5-minutes.  An example is http://www.wrh.noaa.gov/mtr/sfcobs2.php.  While at first blush this seems like an awesome way to see more timely data, it can cause confusion when comparing it to daily maximum and minimum readings.

Example of 5-minute readings:


The 5-minute readings are actually an "instantaneous" 1-minute observation at the particular time noted. The problem arises in that the maxima and minima are a "5-minute average" of five adjacent individual 1-minute readings.  Consequently, that average could be less than one of the 5-minute readings.

For example, at the hottest time of the day you have an instantaneous 5-minute reading of 85 degrees at 14:30.  However, if the readings at 14:27, 14:28, 14:29 and 14:31 were all 84 degrees, then the maximum reading would be 84.2, which would be rounded to 84.

Correction: In rereading the ASOS criteria I think I misinterpreted how’s it’s calculated (i.e., the 5-min values are the average of the previous five 1-min values) and that rounding due to C to F conversions may be more of a factor.  But overall I am right for the wrong reasons and for the real world the confusion remains with seeing different 5-min values than the climatological max/min temps.



Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

 

Posted

End of the 2015-16 Rainfall Season


Today is the last day of 2015-16 California rainfall season and it certainly has been an interesting one.  Going into the season with El Niño developing in the Pacific, I don't know anyone who envisioned that Northern California would have seen a significantly greater percent of normal amounts than Southern California; once again highlighting that 2015-16 was the Poster Child for "All El Niños Are Not the Same".

The map and table below an also be found at http://ggweather.com/ca2015rain.htm.





The following map was generated from the Western Region Climate Center


Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

 

Posted

Is a "Different" La Niña Brewing?

Are the impacts, from the La Niña that is forecast to develop later this year, going to be "typical" or will they be more of an outlier solution like that of the fading El Niño? (Differences Between 2015-16 El Niño and Previous Strong and Very Strong  Events)  

A comparison of the current NASA Sea Surface Height anomalies and those in May 1998 show some reason to keep an open mind. Note the large positive anomaly north of the equator; which is the same mass that was at least partially responsible for the 2015-16 El Niño being atypical.

And this area is literally outside of the Niño 3.4 box where SST anomalies are measured and used to gauge the presence and strength of ENSO events. Consequently, while the Oceanic Niño Index (ONI) may be showing cooling, this area will need to be watched as well.

In that context, even La Niña - Anything Goes for California Precipitation may not give enough clues for this coming winter. As always, it will be interesting and challenging. Stay tuned.


Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com




Posted

Updated Golden Gate Weather Services Web Resources

The following pages have been updated.  As always, let me know of any changes, corrections or additions.

2016 Thunderstorm & Tornado Resources

2016 Hurricane Resources 

2016 Fire Weather Forecasts and Links 

El Niño/La Niña Resources

Heatstroke Deaths of Children in Vehicles


All of the above, and much more, can be accessed from the Meteorologist's Links page. 



Blog: Most of these emails and other material get archived in the Golden Gate Weather Services Blog.

Twitter:  Short updates and links send more frequently via @ggweather 




Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

 

Posted

La Niña - Anything Goes for California Precipitation


In looking at past La Niña events, the one thing that is clear is that almost anything can happen when it comes to winter precipitation across the Golden State.  The images below show the "average" precipitation for the 20 previous La Niña events going back to 1950 but more importantly the wide range from the driest to the wettest California winters (Nov. - Mar.) for each of the categories (Weak, Moderate and Strong).  [Additional images and data can be found at US Winter Precipitation & Temperature Climatology: La Niña and California Climatology of La Niña Events and Precipitation]






 


The bottom line is that it is too early to tell the strength of forecast La Niña and more importantly even within a specific strength category the range of solutions leaves no clear signal based on the past climatology.

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com


Posted

Northern Sierra Precipitation Tops Seasonal Normal

The 8-Station northern Sierra Nevada (see map) precipitation Index (8SI) has reached a milestone. Rain and snow over the weekend pushed its total since July 1st to 55.71". This is over an inch above normal for the entire seasonal (July 1 to Jun 30) total of 54.52”.  Normal 8SI for the remainder of April plus May and June is approximately an additional 4 inches.



The 5-station San Joaquin Basin Index is now at 39.71" compared to their seasonal total of 42.57" and the 6-station Tulare Basin Index is at 26.00" compared to their full season normal of 30.50".



Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com


Note: There will be a minor discrepancies between these figures and those published by Calif. DWR which uses the Oct. 1 Water Year instead of the historical rainfall season of July 1 to June 30.  And inexplicably DWR also does not use the standard 30-year climatological normal (1981-2010) but rather non-standard average period of 1922-1998 for the 8-Station Index (50.00") and 1961-2010 for the 5 and 6-Station Indices.   

 

 

Posted

Precious Cargo

As the temperatures begin to go up, sadly so do the number of children who die after being left inside hot vehicles.  Already in 2016 there has been the two such deaths nationwide.  And it does not have to be a blazing hot day in a southern state for these tragedies to take place as evidenced by the fact of deaths in places like Seattle and Milwaukee on mild days. 

We have all heard about an isolated incident of a child dying in a hot car.  However when put into a nationwide context they constitute an epidemic; claiming on average 37 young lives every year in the United States.  Since 1998 over 662 infants and children have died horrible deaths due to heatstroke inside hot vehicles.  But you can help save some of these precious lives!

Sadly, these incidents often intersect with the early childhood education and childcare communities.  Over half (54%) of juvenile vehicular hyperthermia fatalities occur when a caregiver is somehow distracted and accidentally leaves a child in a vehicle.  And in nearly half of these cases, the child was supposed to be dropped off at either childcare or preschool.  These cases happen to parents, grandparents, siblings and childcare providers.  It is often a matter of a change of routine, where one person normally is responsible for a child and on a given day another person forgets they have the responsibility that day.

The other categories of circumstances that lead to heatstroke deaths in vehicles are children playing in vehicles and children intentionally left in vehicles.  In the former, which account for about 29% of the cases, children gain access to a vehicle and are subsequently overcome by the heat.  And sadly in the latter instance that makes up about one-in-five of the deaths (17%), children are intentionally left in vehicles by a caregiver who has to run an errand, go to work, go to bar or the casino, etcetera.

What is heatstroke (aka hyperthermia)?  In the simplest terms it describes heat-related illnesses when a body’s temperature exceeds its normal range.  If a body is subjected to extreme temperatures it can overwhelm the body’s ability to cool itself.  This is especially true for infants and children whose body’s heat at a rate of three to five times faster than adult.  If a person’s body temperature reaches 104 degrees (the clinical definition for heat stroke) their cooling system is overwhelmed to the point it begins to shut down.  A person with heat stroke may experience symptoms that include confusion, faintness, strong and rapid pulse, and possible delirium, hot dry skin or even unconsciousness.  Continued exposure to very high temperatures can produce brain damage, and at 107 degrees cells with the body start to die and organs begin to shut down, quickly leading to death.

In the summer of 2002 a controlled study was conducted to quantify how hot vehicles get and how rapidly they can reach dangerous temperatures.  This research was published in Pediatrics and is maintained on line at http://noheatstroke.org.  The conclusions of the research were startling in how extreme the conditions inside a car can reach.  Within the first 10 minutes a vehicle will warm to almost 20 degrees above the outside air temperature; after 30 minutes it is 34 degrees warmer. After an hour it plateaus at as much as 45 to 55 degrees higher than the air outside.  Consequently, even on a mild 70 degree day temperatures can reach readings that can be fatal to an infant or small child.  The research also found that “cracking” the windows had a negligible effect on the temperature.

This research has become the “go to” article on the topic and is used worldwide and hopefully will raise the level of interest and awareness about this sad topic and ultimately to save some innocent lives.  The bottom line is that each and every one of these deaths is 100% preventable.  Infants and children are the most precious cargo that is ever transported in a vehicle and we should always be cognizant of the potential dangers to a child left alone in a car.

Jan Null, CCM
San Jose State University
http://noheatstroke.org
jan.null@sjsu.edu

~~~~~~~~~~~~~~~~~~~ 

Safety Recommendations

• NEVER LEAVE A CHILD UNATTENDED IN A VEHICLE.  NOT EVEN FOR A MINUTE !
• Be sure that all occupants leave the vehicle when unloading. Don't overlook sleeping babies.
• Always lock your car and ensure children do not have access to keys or remote entry devices.  If a child is missing, check the pool first and then the car, including the trunk. Teach your children that vehicles are never to be used as a play area.
• Keep a stuffed animal in the carseat and when the child is put in the seat place the animal in the front with the driver.
• Or place your purse or briefcase in the back seat as a reminder that you have your child in the car.
• Make "look before you leave" a routine whenever you get out of the car.

 

Posted

March and Season-to Date Rainfall summary


March rainfall across California was somewhat reflective of the season-to-date with above normal totals farther north in the state. 


See: http://ggweather.com/seasonal_rain.htm

These numbers continue to tell the story that this El Niño was "different". (See http://ggweather.com/enso/compare/)

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com 


Note: There will be a minor discrepancies between these figures and those published by Calif. DWR and some NWS offices which uses the Oct. 1 Water Year instead of the historical rainfall season of July 1 to June 30. DWR also does not use the standard 30-year climatological normal (1981-2010) but rather non-standard average period of 1922-1998 for the 8-Station Index and 1961-2010 for the 5 and 6-Station Indices. 

 

Posted

La Niña in our Future?

Even as El Niño continues to influence this winter's weather, questions are arising about whether there is a La Niña on the horizon for next winter. There seems to be a general impression that La Niña is expected to follow El Niño.  The following is a breakdown of all the El Niño events and what ENSO events occurred the following winter.



In summary and considering all El Niño events, they only transitioned to La Niña less than half the time (i.e., 10 out of 23), with 7 years become Neutral and the final 6 remaining as El Niño. Breaking out just the five strong and very strong El Niño's, 3 of these became La Niña, with the the other two splitting one each into the weak El Niño and Neutral categories.

 

The latest IRI/CPC plume of ENSO predictions for next fall/winter is characterized by a broad range of solutions from remaining as an El Niño to well into the La NIña category. The average, of all the models, straddles the line between neutral and a weak La Niña with -0.5 for Nov-Dec-Jan.



BOTTOM LINES:  First, there is currently no definitive answer about the character of ENSO for next winter; either from past climatology or the forecast models. But more importantly (and as a lesson learned from the current El Niño) is that even within a particular category of ENSO there are lots of subtleties that affect the ultimate impact on related weather patterns. Stay tuned.

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

 

 

Posted

Drought Update

 

Yes, in the past two weeks there has been significant improvement to the drought impacting California. But there is still a long way to go.  And in viewing the Drought Monitor,  and other drought products, it should be kept in the context that one-size-does-not-fit-all to measure hydrologic imbalance in California.



Defining drought in California is a conundrum of multi-faceted issues. One aspect is that drought impacts different users in very different ways and on very different time scales. While a local water district might fill all of its reservoirs and have a two-year reserve, another adjacent district might rely more on ground water and imported water and still have a deficit. Likewise, for some sectors of agriculture (the user of more that 75% of the water in the state) there might now be adequate supplies, the same is not true for a different crop.

And an overarching parameter is that drought must also be viewed in the context of the complex California water supply and delivery infrastructure. Consequently, even though the bulk of this winter's has been in the northern half of the state there will be some reduction of impacts statewide. 
 


Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com
 

 

Posted