tag:ggweather.posthaven.com,2013:/posts Golden Gate Weather Services 2017-06-28T16:16:34Z Jan Null tag:ggweather.posthaven.com,2013:Post/1168520 2017-06-28T16:13:48Z 2017-06-28T16:16:34Z Summary of 2016-17 California Rainfall Season

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This Friday, June 30th, marks the end of a rather remarkable California rainfall season. Here are some of the numbers highlighting the past very wet 12 months.

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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1166616 2017-06-22T20:32:15Z 2017-06-22T20:33:22Z Too Hot for Dogs Too!

DO NOT walk your dog in the heat! Besides possible heatstroke, just like humans, your dog could likely be scorching the pads on his paws. Veterinarians say that burns can occur when the surface exceeds 125 degrees. To illustrate, I took some measurements of some surface temperatures today at 10:30 am and again at 12:30 pm. And these are still not the hottest time of day! As a rule of thumb (or paw), if you can't stand on it barefoot then don't let your dog walk on it! 

Jan Null, CCM
Golden Gate Weather Services
jnull@ggweather.com

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1165414 2017-06-19T14:23:37Z 2017-06-19T14:26:49Z Don't Trust Your Car's (or Bank's) Thermometer

With the warm weather I’ve been hearing about LOTS of really hot outlier temperatures being reported from car thermometers; and their owners wondering why they’re so different from official temperature reports. To clarify, let’s look first at how the official temperatures are measured.

There are four general guidelines for accurately measuring air temperatures.
- The thermometer must be outside of direct sunlight., otherwise you are measuring the sun’s intense shortwave energy and not the air temperature.
- It should also be in a well ventilated environment that’s representative of surrounding air, not in an enclosed area.
- Official temperatures are taken at about 5 feet above a natural surface and not a heat-retaining surface like concrete or asphalt. There can be as much as a 25 degree difference between air right above the ground and that at 5 feet.

- And measurements should also be far enough away from other heat emitting sources like walls and vehicles as to not be biased.

Conversely, the thermometers on most cars violate just about every one of the above guidelines. They are usually located under the front grillwork or adjacent body panel, only a foot or two above the highway or parking lot. Especially when a car has been sitting it is measuring the air heated by the parking surface plus any residual heat being given off by the vehicle itself. Even when a car is moving the temperature readings are upwardly biased by the heat given off by the roadway and the vehicle. It’s been my experience that car outside temperatures at startup on a warm day can be more than 10 degrees to toasty, and even while they seem generally to be at least 5 degrees too warm.


Similarly, the readings from locations like bank thermometers and some backyard thermometers don’t do a good job of accurately capturing the air temperature for some of the same reasons.

So when you next start up your car and see a dashboard outside temperature reading of 120° you can take solace in the fact that it’s probably only 105°!

Jan Null, CCM
Golden Gate Weather Services

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1150762 2017-05-01T15:55:52Z 2017-05-01T15:58:12Z California April Weather and Rainfall Season Summary

April was generally wetter than normal across California, except south of the Tehachapi's; while there were above normal temps near the coast and cooler readings inland.  See California Key City Climatology.

The seasonal rainfall continues to be mostly well above normal through the end of April, especially in the important Northern and Central Sierra Nevada watersheds. See California Rainfall Season to Date  and


The California Precipitation Snapshot has also been updated. 

Jan Null, CCM
Golden Gate Weather Services
jnull@ggweather.com

 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1149863 2017-04-27T15:57:16Z 2017-04-27T15:58:55Z NOT the end of the rain for the season

No, it's NOT yet the End of the Rainfall Season!!

Despite proclamations by several individuals, the most recent rainfall does NOT mark the end of California's rainfall season. Yes, the amounts drop off significantly as we transition into late spring and summer, but climatologically it would be quite unusual not to have rain in May and June. For example, the last time that San Francisco had zero rain for the months of May and June was in 1978!

Below are the normal rainfall amounts and the normal number of days of rain across California for May and June.


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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1137304 2017-03-09T17:17:16Z 2017-03-09T17:19:19Z A Look Back at the CPC 2016-17 Winter Outlooks


It's time to take a quick look back at the good, the bad and the ugly of the CPC Winter Precipitation and Temperature Outlooks from this past winter. Because of the probabilistic nature of this outlooks this review, like previous reviews, is very subjective. But at least in the West, when their sub-headline for the just finished winter was "Drought expected to persist in California" followed the previous winter's busted above normal El Niño forecast, the efficacy of the product certainly needed scrutiny. See or details CPC Winter 2016-17 Seasonal and Monthly Precipitation and Temperature Outlooks in Review:




Jan Null, CCM
Golden Gate Weather Services
jnull@ggweather.com

  

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1136987 2017-03-08T19:13:50Z 2017-03-08T19:14:54Z California 2nd Rainiest Jul-Feb

 

Statewide, the first eight months of the current rainfall season were the 2nd wettest on record in California going back to 1895-96. This season's 28.03" statewide was just short of the 1968-69 record of 28.30". Looking at the individual climate divisions, the Sacramento drainage (Clim Div 2) and the Northeast Interior (Clim Div 3) had their wettest ever, while the San Joaquin drainage (Clim Div 5) had their 3rd wettest. Neither of the Southern California climate divisions (i.e., Clim Div 6 and 7) were in the top 10.    



Jan Null, CCM
Golden Gate Weather Services
jnull@ggweather.com

 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1135788 2017-03-03T17:23:19Z 2017-03-03T17:25:48Z California Rainfall Data Archive


In response to many many requests for how this rainfall season compares to previous wet years I have put together an archive of monthly rainfall for data for about 50 California locations. The data is cobbled together from a variety of NOAA and NWS sources. The data is for each location's entire period of record, but beware some locales have missing data. My plan is to update this at the end of the rainfall season (i.e., June 30). Please let me know of any comments, errate of suggestions. See http://ggweather.com/monthly/ . Enjoy.



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

 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1135283 2017-03-01T23:16:26Z 2017-03-01T23:18:16Z Ranked SF Bay Area and Sierra February and Jul-Feb Rainfall

 





 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1130250 2017-02-10T18:21:18Z 2017-02-10T18:38:53Z Rainfall Season vs. Water Year

 

Unlike most parts of the United States, California’s Mediterranean climate is defined by its “summer drought” given that there is a natural break between one rainy season and the next.  This was recognized by settlers as far back as the Gold Rush and since that time the most common metric to quantify California (and other western states’) rainfall has been a July 1 to June 30 “rainfall season”. Consequently, thousands of reports, studies and analyses related to California rainfall have been based on the rainfall season, including the following from is some of the earliest chronicling of California weather.
 

Conversely, because there is lag of several months to when streamflows in the state’s rivers are at their lowest, hydrologists have historically (and logically for their purposes) used a Water Year (WY) metric from October 1 to September.

However, about two years ago, for reasons that have never been adequately explained, the National Weather Service (NWS) Western Region decided, without the opportunity for comment from the rest of the meteorological community or the public, to start calculating their rainfall products (i.e., Climate Station Precipitation Summary , and others) in regards to the hydrologist’s Water Year. (The remainder of the NWS, by the way uses the calendar year for summarizing rain data, as they do not have a natural summer break in rainfall.)  While this might be nice for consistency with the hydrologic community it puts them out of step with the vast wealth of historic data and others in the rest of the meteorological community.  This was even highlighted by a recent article in the LA Times, “Ideologies clash as weather service realigns rainfall calendar

The numerical differences between rainfall season and water year are slight (i.e., typically only about 3% of the annual amount) given the small amount of rain that typically falls in the months of July, August and September. And that rain is not lost, it is either counted at the end of one methodology’s season or the beginning of the other’s.

As stated about, the problem comes about when trying to compare data published by the NWS in terms of the hydrologist’s WY, with data from past events which have been characterized by meteorologists’ rainfall season.  [To their credit, NWS San Francisco Bay Area automatically generates a table which has both the rainfall season and water year, and it is my understanding the software used was made available, but unfortunately not adopted, by other NWS offices.]

An effort has been made, outside the NWS, to make available to the public and meteorological community data showing rainfall in terms of the July 1 to June 30 rainfall season with products like California Rainfall Season Totals. But this does not address the amount of unnecessary effort expended by everyone, but a very small group, to keep the data consistent and meteorologically logical.
 
Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com
jnull@ggweather.com

 


 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1127654 2017-01-31T18:41:22Z 2017-01-31T18:42:52Z Not the Wettest January or Season to Date


Yes, January and the Rainfall Season to date (July 1 to January 31) have been wetter than normal, but they are far from "the wettest" or record-setting. Only the 5-station Central Sierra Index had their wettest January on record, but that period of record goes back to only 1913, more than 60 years shorter than most of the other records. Of the individual stations with long periods of record extending back to the mid-19th century, San Francisco's 9.42" was only the 16th rainiest and Redding's 11.45" was their 23rd wettest.

Likewise, the season-to-date number have been impressive, but most have not even been in the top 10 wettest. 


The following are the Top 10 Wettest Januarys.


The following are the Top 10 Wettest July through January.


Jan Null, CCM
Golden Gate Weather Services
jnull@ggweather.com

 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1125356 2017-01-23T17:13:24Z 2017-01-23T17:13:24Z California Precipitation Snapshot California Precipitation Snapshot

 

California continues to rack up impressive rainfall totals. All 3 of the Sierra indices are within a storm of normal for entire season (Jul 1 - Jun 30)!  Sacramento has already exceeded a full season. See http://ggweather.com/water/


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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1125354 2017-01-23T17:12:01Z 2017-01-23T17:12:01Z California Precipitation Snapshot California Precipitation Snapshot

 

California continues to rack up impressive rainfall totals. All 3 of the Sierra indices are within a storm of normal for entire season (Jul 1 - Jun 30)!  Sacramento has already exceeded a full season. See http://ggweather.com/water/


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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1125352 2017-01-23T17:08:51Z 2017-01-23T17:11:38Z California Precipitation Snapshot California Precipitation Snapshot

 

California continues to rack up impressive rainfall totals. All 3 of the Sierra indices are within a storm of normal for entire season (Jul 1 - Jun 30)!  Sacramento has already exceeded a full season. See http://ggweather.com/water/


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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1121766 2017-01-09T17:37:23Z 2017-01-09T17:40:43Z California Precipitation Snapshot; Bay Area Storm Index

The California precipitation picture got a lot prettier over the weekend; especially in Sierra Nevada which saw huge gains. For example the the southern Sierra Nevada (i.e., Tulare Basin) jumped from 103% of normal on January 1 to 165% through yesterday (January 8), while the northern and central Sierra increased to 173% and 172% respectively. See  http://ggweather.com/water/



In the San Francisco Bay Area the Sunday storm ranked as an 8.5 on the Bay Area Storm Index (BASI).  This was based on a 24-hour downtown San Francisco rainfall total of 1.62", a maximum sustained wind at SFO of 44 mph and a peak (below 1500' elevation) wind gust of 75 mph at Spring Valley in San Mateo County above Crystal Springs. This is the highest ranked storm since October 2009 (see archive).  

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1119893 2017-01-02T13:33:18Z 2017-01-02T13:37:38Z December Summary; Seasonal Precipitation Snapshot; La Niña; AMS in Seattle December Summary; Seasonal Precipitation Snapshot; La Niña; AMS in Seattle


December rainfall in California was pretty much upside down compared to recent months, with near normal rainfall in the north and above normal in the south. San Diego totaled 4.22 inches (276% of their December normal) while Los Angeles had 4.55" (195%). The northern third of the state was close to normal with just rain-shadowed San Jose lagging behind at 58%. [http://ggweather.com/calif/dec2016.htm]

Despite a couple colder than normal periods, only Eureka and Sacramento had monthly average minima of more than 2 degrees below normal. At the same time, LA and San Diego average monthly minima were more than 2 degrees above normal.
[http://ggweather.com/calif/dec2016.htm]

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A snapshot of the first six months of the rainfall season (July 1 to June 30) shows totals well above normal at most locations, with the biggest gains against normal in the south, where Los Angeles and San Diego pushed to 138% and 158% of normal respectively. http://ggweather.com/water/

See also http://ggweather.com/seasonal_rain.htm which is updated daily, in the early evening.

With the potential for extensive rains in the next 10 days, I have updated the Rainfall, River and QPF Page .

~~~~~~~~~~~~~~~~~~~

La Niña's cooling in the tropical eastern Pacific may have bottomed and the weekly Sea Surface Temperature Anomalies (SSTAs) for the past month have averaged just -0.4.

~~~~~~~~~~~~~~~~~~~

Finally, I am headed for the 97th AMS Annual Meeting in Seattle later this month to present a paper of Heatstroke Deaths of Children in Vehicles. If you are also going to be in attendance, drop me an email and we can try to connect.
~~~~~~~~~~~~~~~~~~~

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather

 

 


 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1116726 2016-12-19T17:27:45Z 2016-12-19T17:28:50Z California Precipitation Snapshot

I've created a new web page, California Precipitation Snapshot, that graphically summarizes the current rainfall season at 8 major city locations (San Francisco, San Jose, Sacramento, Eureka, Redding, Fresno, Los Angeles and San Diego) plus the three Sierra Nevada Precipitation Indices.  See http://ggweather.com/water/



Happy holidays.

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

 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1112215 2016-12-01T17:04:40Z 2016-12-01T17:07:07Z California Rainfall at the Beginning of Winter

Today, December 1st, begins meteorological winter; the three coldest months in the Northern Hemisphere. And for most locations in California it corresponds to the three wettest months.

After a much wetter than normal October (http://ggweather.com/calif/oct2016.htm) for Northern and Central California the November totals (http://ggweather.com/calif/nov2016.htm) were more of mixed bag, but still concentrated in the north.  Consequently the totals for the first five months of the rainfall season (July 1 to November 30) have the northern half of California above normal (http://ggweather.com/seasonal_rain.htm).  

Given the rainfall bias in the north the Drought Monitor is showing relief there but still 43% of Calif in Extreme or Exceptional Drought.



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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1106848 2016-11-09T18:35:18Z 2016-11-09T18:35:18Z A Different Flavor of La Niña?

Unlike those picture puzzles where you are asked to find subtle differences between images, a look at the NASA sea surface height anomaly images for the past three weak La Niñas (1995, 2000, 2011) plus this year (2016), leaves little doubt that what's going on in the eastern Pacific is not subtle at all.  The most striking difference is the anomalous warm water from the equator north to about 25 degrees north. This area warmed in conjunction with last year's very strong El Niño and may have contributed to the atypical winter along the west Coast of North America (see "Differences Between 2015-16 El Niño and Previous Strong and Very Strong Events").




With the current Oceanic Niño Index (ONI) already at weak La Niña levels, tomorrow's updated CPC ENSO Advisory is likely to up the odds for a La Niña this fall and winter. But can we still use the standard "La Niña playbook" of looking at past events as an indicator of broad-scale for West Coast precipitation patterns for this winter?  Last winter the conventional wisdom for the impacts of a very strong El Niño did not work out per previous events. Consequently, it looks like extreme caution should be exercised in looking for patterns based upon the climatological past related to the prospects for current La Niña. 

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


Miscellaneous La Niña Resources (use with caution):
La Niña Winter Precipitation & Temperature Climatology  
California Climatology of La Niña Events and Precipitation  
California Precipitation Climatology for Cool Neutral and Weak La Niña Events  

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1104626 2016-11-01T17:27:23Z 2016-11-01T17:30:24Z October Rain Only "A Good Start"

 

October 2016 was a wet month in the northern two-thirds of the state but the south continued to be pretty dry.  (See: summary)  Monthly rainfall ranged from over 450% of normal at Eureka and Sacramento, while Los Angeles and San Diego only had 79% and 12% of their normal October rain respectively. But these numbers need to be put into context as October normals are relatively small and there is not a statistically significant relationship between October rainfall and how the rest of the rainfall season (July 1 to June 30) ultimately ends up.

San Francisco’s 2.43 inches for the month is 217% of normal (1.12”), but this ranks as only the 23rd wettest October going back to 1849. The wettest was 7.28” in 1889 (below).  One factor affecting the perception of it being a very rainy month were the number of days of rain. This year there were 12 days of measurable rain in San Francisco, the second highest number on record.  The most was 13 days in that very wet October of 1889.

Looking at the 25 wettest Octobers (below) there is not a correlation to how the seasons ultimately ended up; other than being a “good start” by saturating the soil to enhance future runoff and significantly reducing the fire danger. Eleven of those 25 wettest Octobers actually ended up below the 168-year average of 21.57”. This including the 2nd driest season on record; 1975-1976 when the season ended with a paltry 8.05”.



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


 
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Jan Null
tag:ggweather.posthaven.com,2013:Post/1087541 2016-09-07T15:53:52Z 2016-09-07T16:44:36Z When is the Hottest Day of the Year?

 

As we head toward the Autumnal Equinox (Sept. 22 @ 7:21 am pdt) most cities around California and the nation are well past their normal hottest day of the year, which typically occurs about a month after the Summer Solstice. But a few locations, especially along the West Coast, wait until August and even September to peak. And San Francisco is certainly the latest of any major United States city by not reaching its normal highest maximum temperature of 70.4 until September 24th.

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




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Jan Null
tag:ggweather.posthaven.com,2013:Post/1085629 2016-09-01T13:41:06Z 2016-09-01T13:43:28Z Mixed 2016 California Summer Temperatures

Overall the summer of 2016 was a real mixed bag in regards to California temperatures.  The average maximum temperatures anomalies for meteorological summer (i.e., Jun-Jul-Aug) ranged from below normal near the coast from about San Francisco north to above normal over most of the remainder of the state. (http://ggweather.com/calif/summer2016.htm). It should be noted that in San Jose the average summer temperature was right on "normal" with an anomaly of zero!  
 
The average summer maxima for the past seven years has likewise been mixed, with no year showing the same (i.e., positive or negative)  anomaly for all 8 cities. And only Fresno had the same, in this case positive, for all seven years. (Below)




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

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1084188 2016-08-26T15:15:09Z 2016-08-26T15:18:35Z One of the mildest San Francisco Augusts in 143 years

Temperature records in San Francisco began in 1874 and this August will tie as only the 4th time that there was not a daily maximum temperature all month that did not exceed 70 degrees. In 1942 the highest reading for the month was only 67 degrees, while in 1917 and 1882 the highest was 69. On August 8, 2016 the maximum was just 70 degrees, tying it with 1881.

So far in August 2016 the average maximum temperature has been 64.6, and given forecast maxima of around 64 degrees for the remainder of the month this will change little. The normal August high temperature in San Francisco is 68.1. But even with prolonged coolness, the average for the month will only rank as about the 35th coolest on record.

The major player in the mild weather has been a persistent weak trough of low pressure over the West Coast for most of the month and a likewise persistent marine layer.  It should be noted that the sea surface temperatures along the coast west of San Francisco remained above normal for the entire month.


The story is different farther inland and away from the cool coastal air with August monthly maximums generally above normal.


Finally I would be remiss if I did not point out that Mark Twain NEVER SAID "the coldest winter I ever spent was summer in San Francicsco". (per http://www.marktwainproject.org/).  But if he had, it would likely have been a year like 2016.

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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1082285 2016-08-18T17:36:41Z 2016-08-18T17:43:32Z Calif Precip with Minimal La Niña Forecast


The latest IRI/CPC "plume" forecast is still indicating a minimal La Niña event at best. To that end I have put together a climatology of California precipitation for cool neutral (ONI -0.2 to -0.4) and Weak La Niña (ONI -0.5 to -0.7) events. See http://ggweather.com/enso/ca_lanada.htm and summarized in the graphic below.

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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1079071 2016-08-05T17:37:21Z 2016-08-05T19:56:17Z 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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1068584 2016-06-30T16:45:57Z 2016-06-30T16:51:52Z 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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1055754 2016-05-25T17:15:13Z 2016-05-25T17:16:44Z 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




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Jan Null
tag:ggweather.posthaven.com,2013:Post/1052170 2016-05-17T14:12:00Z 2016-05-17T14:16:25Z 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

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1050369 2016-05-12T15:44:30Z 2016-05-12T15:48:29Z 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


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Jan Null
tag:ggweather.posthaven.com,2013:Post/1040622 2016-04-25T15:40:23Z 2016-04-25T15:42:53Z 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.   

 

 

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Jan Null