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Rainshadow

The GFS's Perpetual Run For The 100s In PHL Thread AKA The Thread That Will Not End

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Hello!

 

Being a retired golfer, gardener always looking for that nice next day to golf and to a lesser extent wondering how big the watering bill will be, its not uncommon for me to be living in week 2 land. Also I was always had an interest in the outlook area of modeling even though I lived in the deterministic world of 7 days and in.

 

In spite of the "catchy" title, as the following maps will show, its not just a GFS issue.  Not sure as to why all of the models just get warmer as they progress in forecast time this summer, but have noticed this first with the GFS for the last week of June when it was forecasting at least once near 100 temps and actual highs were in the mid 80s.

 

Since I did a similar forecast below zero and not get them thread in the winter for the GFS, its "pattern" has given another opportunity.  I have to still work on the raw numbers, but notice in the following charts on how all of the models lose negative height departures as we go forward in forecast time.  The first six charts show initialization and then the 240hr ensemble mean forecast. The next two show how the GEPS and GEFS dont course correct as its just as bad out at 384, if not worse.  The last two charts are a forecast and verification by the GEFS for 00z the 12th of July.  Yes it was a pleasant day and sorry there was no conspiracy theory on my part, this was the earliest available map on the tidbit chart.

 

In subsequent pages, I will be adding any op GFS run that forecasts (forecasted) a 100 degree 2m temp max for PHL. This is a rather conservative approach as its SOP to add 3-5F to that value to get the true expected max temp.  Tom, if you see any op EC(s) that have it, I will add.

 

gfs-ens_z500a_nhem_1.png

 

gfs-ens_z500a_nhem_41.png

 

 

ecmwf-ens_z500a_nhem_2.png

 

ecmwf-ens_z500a_nhem_11.png

 

 

gem-ens_z500a_nhem_1.png

 

gem-ens_z500a_nhem_41.png

 

 

gfs-ens_z500a_nhem_65.png

 

gem-ens_z500a_nhem_65.png

 

Forecast For evening of July 11th

fcst.png

 

Actual For evening of July 11th

actual.png

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Its not just here.  In the summer weather pattern thread  a posted GFS run predicted 104F 2m temp highs for North Platte, NE this Friday (July 15th) and Saturday (July 16th).  The latest GFS MEX MOS has predicted highs of 86 and 87.

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For PHL

 

6/29/00z..........100F on 7/14 actual high 96.

7/5/00z............100F on 7/13 actual high 84.

7/7/12z.............100F on 7/21

7/10/12z...........100F on 7/20, 103F on 7/21, 101F on 7/22, 100F on 7/23

7/10/18z...........101F on 7/25

7/12/12z............101F on 7/21, 105F on 7/24, 104F on 7/25, 105F on 7/26

7/13/18z............104F on 7/24

7/14/00z............100F on 7/28

 

Honorable mention to the 00z/3rd which predicted a 583 thickness for SaturdayJuly 9th. Highest thickness 575.

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Starting with the 00z run on the 8th, these are GFS runs that had at least one 2m max temp forecast high as high as 97-99F which using SOP would translate into a forecast high of 100F or greater for PHL.

 

7/8/00z (was wrong), 7/8/06z (was wrong), 7/8/12z, 7/8/18z, 7/9/00z, 7/9/12z, 7/11/00z, 7/12/06z, 7/13/06z, 7/13/12z, 7/14/06z, 7/14/12z, 7/14/18z, 7/15/00z.....

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Bias or not, models are not backing away from getting PHL to 100 degrees (applying 850/925/2m techniques) on the weekend of 7/23 & 7/24 as of the 15th.

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For PHL

 

6/29/00z..........100F on 7/14 actual high 96.

7/5/00z............100F on 7/13 actual high 84.

7/7/12z.............100F on 7/21

7/10/12z...........100F on 7/20, 103F on 7/21, 101F on 7/22, 100F on 7/23

7/10/18z...........101F on 7/25

7/12/12z............101F on 7/21, 105F on 7/24, 104F on 7/25, 105F on 7/26

7/13/18z............104F on 7/24

7/14/00z............100F on 7/28

7/15/06z............100F on 7/26 (technique 100s on 7/24, 7/25 & 7/27)

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Starting with the 00z run on the 8th, these are GFS runs that had at least one 2m max temp forecast high as high as 97-99F which using SOP would translate into a forecast high of 100F or greater for PHL.

 

7/8/00z (wrong)

7/8/06z (wrong)

7/8/12z on 7/20

7/9/00z on 7/22

7/9/12z on 7/22 & 7/23

7/12/06z on 7/25, 7/26 & 7/27

7/13/06z on 7/28

7/14/06z on 7/23

7/14/12z on 7/25 & 7/29

7/14/18z on 7/24

7/15/00z on 7/23 & 7/30

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Bias or not, models are not backing away from getting PHL to 100 degrees (applying 850/925/2m techniques) on the weekend of 7/23 & 7/24 as of the 15th.

are you just doing Raw value off the model?

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are you just doing Raw value off the model?

 

I am doing both. I am separating them though.  I honestly dont know the bias in Euro 2m temp forecasts in our area.

 

Any raw GFS 2m forecast above 103F once applying the bias correction is a modeling forecast all-time record high for Philadelphia.  I am being conservative on that too, some mets add 5F.  In other words that day run on the 12th, bias corrected would break Philadelphia's all-time record high temp on three successive days.

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I can't break this down into a shorter time period (so its over a year). This stops at 156 hours also btw.  Compare the cold bias in the northeast of the GFS 2m temps to the warm bias over the southern plains.

 

post-27-0-14045900-1468597186.png

 

post-27-0-52307600-1468597186.png

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I am doing both. I am separating them though.  I honestly dont know the bias in Euro 2m temp forecasts in our area.

 

Any raw GFS 2m forecast above 103F once applying the bias correction is a modeling forecast all-time record high for Philadelphia.  I am being conservative on that too, some mets add 5F.  In other words that day run on the 12th, bias corrected would break Philadelphia's all-time record high temp on three successive days.

Yea I'm not sure either. I mean yesterday's 12z run had phl for yesterday only getting to 91 

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Yea I'm not sure either. I mean yesterday's 12z run had phl for yesterday only getting to 91 

 

From what I have seen, I think it runs closer, but without looking at it over several years, unless there is a raw 100F, let's leave it with the GFS?

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From what I have seen, I think it runs closer, but without looking at it over several years, unless there is a raw 100F, let's leave it with the GFS?

sounds good.

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For PHL

 

6/29/00z..........100F on 7/14 actual high 96.

7/5/00z............100F on 7/13 actual high 84.

7/7/12z.............100F on 7/21

7/10/12z...........100F on 7/20, 103F on 7/21, 101F on 7/22, 100F on 7/23

7/10/18z...........101F on 7/25

7/12/12z............101F on 7/21, 105F on 7/24, 104F on 7/25, 105F on 7/26

7/13/18z............104F on 7/24

7/14/00z............100F on 7/28

7/15/06z............100F on 7/26 (technique 100s on 7/24, 7/25 & 7/27)

7/15/12z.............100F on 7/25

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Its not just the GFS (although its way easier to verify) and its not just here.  Hello Saint Louis:

 

post-27-0-79696600-1468616851.jpg

 

Whoops realized, I made yet another error with the chart.  The 00z Tue height is now predicted to be 596. (Was 600.)  A straight up 00z wed to 00z wed height comparison went from 598 to 593.

 

post-27-0-53683900-1468616849.jpg

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Its not just the GFS (although its way easier to verify) and its not just here.  Hello Saint Louis:

 

attachicon.gifthen.jpg

 

Whoops realized, I made yet another error with the chart.  The 00z Tue height is now predicted to be 596. (Was 600.)  A straight up 00z wed to 00z wed height comparison went from 598 to 593.

 

attachicon.gifnow.jpg

 

it better not to do this to you and I in winter with below zero temps. If it shows it better happen.

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For PHL

 

6/29/00z..........100F on 7/14 actual high 96.

7/5/00z............100F on 7/13 actual high 84.

7/7/12z.............100F on 7/21

7/10/12z...........100F on 7/20, 103F on 7/21, 101F on 7/22, 100F on 7/23

7/10/18z...........101F on 7/25

7/12/12z............101F on 7/21, 105F on 7/24, 104F on 7/25, 105F on 7/26

7/13/18z............104F on 7/24

7/14/00z............100F on 7/28

7/15/06z............100F on 7/26 (technique 100s on 7/24, 7/25 & 7/27)

7/15/12z.............100F on 7/25

7/16/00z.............102F on 7/23 (925 rule would be 106F or 107F)

7/16/06z.............106F on 7/31 (technique 100s on 7/24 & 7/30)

 

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it better not to do this to you and I in winter with below zero temps. If it shows it better happen.

Like 435 pm sunsets, its a given.

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GFS For PHL

 

6/29/00z..........100F on 7/14 actual high 96.

7/5/00z............100F on 7/13 actual high 84.

7/7/12z.............100F on 7/21

7/10/12z...........100F on 7/20, 103F on 7/21, 101F on 7/22, 100F on 7/23

7/10/18z...........101F on 7/25

7/12/12z............101F on 7/21, 105F on 7/24, 104F on 7/25, 105F on 7/26

7/13/18z............104F on 7/24

7/14/00z............100F on 7/28

7/15/06z............100F on 7/26 (technique 100s on 7/24, 7/25 & 7/27)

7/15/12z.............100F on 7/25

7/16/00z.............102F on 7/23 (925 rule would be 106F or 107F)

7/16/06z.............106F on 7/31 (technique 100s on 7/24 & 7/30)

 

 

EC For PHL

7/16/00z..............100F on 7/24

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Not sure how you want to do this Tony, but the Euro seems like it's over cooling phl and south due to del bay and ches bay. For instance, next sat the LV, and close by and far nw burbs are all 100-102, then phl is 97? On Sunday, same thing nw of the city is hotter by several degrees, I don't think soooo. Seems like the meso stuff is just messing it up. I would include sat/sun for 100 heat on this run and maybe monday too.

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Not sure how you want to do this Tony, but the Euro seems like it's over cooling phl and south due to del bay and ches bay. For instance, next sat the LV, and close by and far nw burbs are all 100-102, then phl is 97? On Sunday, same thing nw of the city is hotter by several degrees, I don't think soooo. Seems like the meso stuff is just messing it up. I would include sat/sun for 100 heat on this run and maybe monday too.

While unlikely, I think it has happened before.

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Not sure how you want to do this Tony, but the Euro seems like it's over cooling phl and south due to del bay and ches bay. For instance, next sat the LV, and close by and far nw burbs are all 100-102, then phl is 97? On Sunday, same thing nw of the city is hotter by several degrees, I don't think soooo. Seems like the meso stuff is just messing it up. I would include sat/sun for 100 heat on this run and maybe monday too.

If it don't have, it don't have it. Not every run is completely logical. Its just like the pcpn hole in a qpf field being correct at that point because much less pcpn fell overall. Sometimes the core of the hotter air loops around the region. Not saying this is the case this time, but there are enough runs between now and the next weekend for one run to not be the deciding factor.

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99 on euro for phl for sat, LV, nw burbs, immediate burbs low 100s sat and sunday... EPS mean for phl peaks at 95, upper 90s for abe.

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