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GaWx

Summer 2015 pattern discussion

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The GFS has been way inaccurate with temps. I would take it with a big block of salt.

 The 13km GFS raw 2meter temperatures have a warm bias that has been acknowledged in documentation. However I do not believe this fully explains some of the ridiculous highs we have seen forecasted around CHS. If memory serves correctly model domains do not actually reach down to the surface so when you see 2meter temperature maps it does not come from direct output. To calculate 2 meter temperatures some kind of extrapolation is used down to that level.  Generally when you have fair weather its better to use MOS output rather than the raw numbers. However, I've noticed that GFS MOS has been consistently too low by as much as 4 degrees Fahrenheit for CLT. For example the last few runs of the GFS MOS output for todays highs have been 93 or 94. At 2pm CLT is already at 96 and will probably climb 1 or 2 degrees more. It was the same with the heat wave last month so in this case using a blend of MOS and raw high temperatures is best. NAM MOS has been performing better as well.

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 The 13km GFS raw 2meter temperatures have a warm bias that has been acknowledged in documentation. However I do not believe this fully explains some of the ridiculous highs we have seen forecasted around CHS. If memory serves correctly model domains do not actually reach down to the surface so when you see 2meter temperature maps it does not come from direct output. To calculate 2 meter temperatures some kind of extrapolation is used down to that level.  Generally when you have fair weather its better to use MOS output rather than the raw numbers. However, I've noticed that GFS MOS has been consistently too low by as much as 4 degrees Fahrenheit for CLT. For example the last few runs of the GFS MOS output for todays highs have been 93 or 94. At 2pm CLT is already at 96 and will probably climb 1 or 2 degrees more. It was the same with the heat wave last month so in this case using a blend of MOS and raw high temperatures is best. NAM MOS has been performing better as well.

True, the heat cells near CHS and GSP are perplexing to say the least, but i also noticed that CLT has been awfully hot this summer, more like CAE kinda hot which i find pretty weird. As a matter of fact, its been hotter at CLT than where i live in Blythewood SC in Northern Richland county.

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but i also noticed that CLT has been awfully hot this summer, more like CAE kinda hot which i find pretty weird. As a matter of fact, its been hotter at CLT than where i live in Blythewood SC in Northern Richland county.

 

scwxfan, I have noticed this as well, much to my chagrin.  

 

Here are the average high temperatures over the past month (6/9-7/8) for some select cities:

94.7 - Columbia

93.7 - Charlotte (warmest all time for the 6/9-7/8 period back to 1871)

93.7 - Augusta

92.8 - Greenville, NC

92.7 - Charleston

91.9 - Fayetteville

91.8 - Raleigh

90.8 - Greer

 

Charlotte is almost never hotter than Fayetteville in my experience.  One possible reason why Charlotte has been so hot is that I've noticed that the Piedmont trough has tended to setup between Charlotte and Fayetteville.  West of the trough, the higher dewpoints get mixed out, so it's hotter but a little less humid...while east of the trough, it's not quite as hot, but more humid.  So Charlotte is kind of in that location where the max heating is occuring just west of the trough axis.  That's a possible reason for the difference anyway...I'd be interested in hearing other feedback.

 

Heat.gif

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scwxfan, I have noticed this as well, much to my chagrin.  

 

Here are the average high temperatures over the past month (6/9-7/8) for some select cities:

94.7 - Columbia

93.7 - Charlotte (warmest all time for the 6/9-7/8 period back to 1871)

93.7 - Augusta

92.8 - Greenville, NC

92.7 - Charleston

91.9 - Fayetteville

91.8 - Raleigh

90.8 - Greer

 

Charlotte is almost never hotter than Fayetteville in my experience.  One possible reason why Charlotte has been so hot is that I've noticed that the Piedmont trough has tended to setup between Charlotte and Fayetteville.  West of the trough, the higher dewpoints get mixed out, so it's hotter but a little less humid...while east of the trough, it's not quite as hot, but more humid.  So Charlotte is kind of in that location where the max heating is occuring just west of the trough axis.  That's a possible reason for the difference anyway...I'd be interested in hearing other feedback.

 

Heat.gif

Wow, nice to know about Charlottes warmest period for that interval.

I will add that the region around and just west of Charlotte has had very little rainfall in the last 60 days. I live at the end of the arrow just 5 miles west of KCLT and I have only had just over an inch and a half of rain since May 1st.  Unlike Columbia or Fayetteville where rainfall has been near normal  the soil is so dry most of the sunlight goes into heating the ground and thus the air above it.

post-962-0-18563400-1436392525_thumb.png

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Charlotte is almost never hotter than Fayetteville in my experience.  One possible reason why Charlotte has been so hot is that I've noticed that the Piedmont trough has tended to setup between Charlotte and Fayetteville.  West of the trough, the higher dewpoints get mixed out, so it's hotter but a little less humid...while east of the trough, it's not quite as hot, but more humid.  So Charlotte is kind of in that location where the max heating is occuring just west of the trough axis.  That's a possible reason for the difference anyway...I'd be interested in hearing other feedback.

 

Here's an example from the 1PM data.  Charlotte sits at 95 with dewpoint of 59, while Raleigh is at 91 with dewpoint of 73.  So there's a trough in between the two with westerly winds and a bit drier air (relative) to the west of the trough and southwest winds and a bit more humid to the east of the trough

 

 

TPDEW.gif

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Charlotte now at 99F, while Columbia sits at 96F.

 

It's just brutal everywhere today.  High heat and drier in western Carolina, and hot and humid down east.  White color is 56 and lower dewpoint.  Lower dews east of the mtns matching up well with the areas with the least amount of rain over the past 2 months that UNCC posted

 

image.gif

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Sorry can't attach the image but can some explain why we have a -ao and a pretty deep -nao and a +pna and we have these temps and no rain. Thanks.

Because southeast weather sucks regardless of the pattern.

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That's awesome, Solak! Maybe when it's ready for harvest, California could divide it up and send the parts equally to the 3.4 and 4 regions for the next 4 years.

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USAToday's hype headline says...

 

Massive El Niño growing in California, say models

http://www.usatoday.com/story/news/nation-now/2015/07/09/el-nino-california/29921633/?o-growing-in-California-say-models/

That would go with my wet and warm for the winter  :P 

 

Hope they're not stealing water like Selleck to make it grow, though.

 :lol: 

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Even a very strong Nino's could easily still end up near normal tempwise in the SE (i.e., no torch) while the N US and Canada torch. Analogs suggest a much better than average chance for one major winter storm in at least the ATL-AHN corridor. I know Burns & Mack are so excited to hear this.

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Even a very strong Nino's could easily still end up near normal tempwise in the SE (i.e., no torch) while the N US and Canada torch. Analogs suggest a much better than average chance for one major winter storm in at least the ATL-AHN corridor. I know Burns & Mack are so excited to hear this.

After this dusty , dry , Death Valley like, summer of 93 redux, I will be ecstatic , if we can just get an active southern jet, to bring the rain and get ground water back to normal! We are entering a moderate drought currently and looks to be getting worse! I'm sure the MJO will stay in phase 5 or something unfavorable for rain! +NAO and such. I really could care less about snow, especially after last years busts and epic sleet storms that were suppose to be "snow" yippee!

Give me above normal rain for 3 or 4 months in a row, and I'll call it a win and just drive to the mountains to play in the snow. :)

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Headed to the SE today for two weeks in SW GA and Panama City FL. Looks like it'll be a bit warmer than we've had in NNE so far. Hopefully we don't get too much weather for the drive.

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Sorry can't attach the image but can some explain why we have a -ao and a pretty deep -nao and a +pna and we have these temps and no rain. Thanks.

In addition to the point made by Griteater, the shortening of the wavelengths of the jet stream in the summer can give different results for the same teleconnection in the summer than they would in winter.  

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