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Post by John G -west belleville on Jul 20, 2019 12:45:02 GMT -6
I thought it might be interesting to post a view of the urban heat island effect as seen by the ABI radiometer on the GOES-16 satellite. Below is an image from channel 14 at 6:00am which is centered on the infrared part of the spectrum at 11.2 um. That's about the center of the range your hand held IR thermometer is looking at by the way. Anyway, you'll see a deep black shade along I-70 from St. Charles Country over to the Mississippi River and into downtown STL which is traditionally the spot where the UHI is maximized in the metro area. This is where the infrared photon flux as seen by the ABI is the highest. One important caveat in the interpretation of infrared imagery...higher fluxes don't necessarily mean warmer surface temperatures though that is typically the case. The reason is because the flux is measured from space and there are two things that modulate flux intensity. The first is obviously the emission of IR photons from the surface. The second is the water vapor content in the atmosphere. WV partially shadows the surface IR flux. More WV means more surface IR flux shadowing from the perspective of the ABI. Those photons don't just disappear; they get returned back to the surface and that's why they get partially hidden from the satellite. That's what is happening on a broad region scale here. There is less WV to the north and more to the south which explains why the IR flux appears higher to the north and lower to the south even though the surface temperatures were roughly the same. But, in the metro area where WV is locally homogeneous you really are observing higher surface temperatures along I-70 and into downtown STL. Can anyone spot anything else interesting?  Bodies of water like Carlyle |
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Post by ComoEsJn on Jul 20, 2019 13:55:30 GMT -6
ha, funny, I'm on the road to Estes Park for a friend's wedding. Where is the wedding? Would be funny if we are staying at the same place lol. the wedding location is called the Della Terra Mountain Chateau |
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Post by jmg378s on Jul 20, 2019 13:58:11 GMT -6
Speaking of cool things to see on satellite today...
You can currently see the sprawling gravity waves emanating from the last nights MCS over the Midwest propagating through the diurnal cumulus fields in the Ohio Valley.
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Post by bdgwx on Jul 20, 2019 15:11:24 GMT -6
I thought it might be interesting to post a view of the urban heat island effect as seen by the ABI radiometer on the GOES-16 satellite. Below is an image from channel 14 at 6:00am which is centered on the infrared part of the spectrum at 11.2 um. That's about the center of the range your hand held IR thermometer is looking at by the way. Anyway, you'll see a deep black shade along I-70 from St. Charles Country over to the Mississippi River and into downtown STL which is traditionally the spot where the UHI is maximized in the metro area. This is where the infrared photon flux as seen by the ABI is the highest. One important caveat in the interpretation of infrared imagery...higher fluxes don't necessarily mean warmer surface temperatures though that is typically the case. The reason is because the flux is measured from space and there are two things that modulate flux intensity. The first is obviously the emission of IR photons from the surface. The second is the water vapor content in the atmosphere. WV partially shadows the surface IR flux. More WV means more surface IR flux shadowing from the perspective of the ABI. Those photons don't just disappear; they get returned back to the surface and that's why they get partially hidden from the satellite. That's what is happening on a broad region scale here. There is less WV to the north and more to the south which explains why the IR flux appears higher to the north and lower to the south even though the surface temperatures were roughly the same. But, in the metro area where WV is locally homogeneous you really are observing higher surface temperatures along I-70 and into downtown STL. Can anyone spot anything else interesting? Bodies of water like Carlyle Yeah, exactly. You can see the locations of bodies of water. Water has a low albedo and takes up the incoming shortwave radiation greedily and converts it into outgoing longwave radiation pretty quick as the skin warms at sun up. Vegetation has a slightly higher albedo so it doesn't absorb as much incoming shortwave radiation and it also uses more of it for photosynthesis so changes in emission of infrared radiation isn't as rapid at sunrise as that of water. By the way, the St. Louis urban heat island is pretty well studied. One interesting hypothesis is that precipitation is slightly higher downwind of the metro area during periods of weakly forced precipitation events like summertime airmass thunderstorms. Surface roughness changes are implicated as well. www.ssec.wisc.edu/~rozoff/papers/rozoffetal2003.pdf |
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Post by mosue56 on Jul 20, 2019 16:28:49 GMT -6
When’s the cold front arriving?
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Post by guyatacomputer - NE St. Peters on Jul 20, 2019 16:38:24 GMT -6
When’s the cold front arriving? Not till Sunday evening or overnight. One more day of this yuck. |
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Post by mosue56 on Jul 20, 2019 17:08:29 GMT -6
Yuck
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Post by mosue56 on Jul 20, 2019 17:46:15 GMT -6
It isn’t allowed to be this hot for the rest of summer! So there!
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Post by demerson- Fletcher MO on Jul 20, 2019 17:55:43 GMT -6
That mcs is heading right for the metro. If it survives.
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Post by cozpregon on Jul 20, 2019 17:58:07 GMT -6
That mcs is heading right for the metro. If it survives.
Has some 14*C 700 temps to fight thru... but it will be interesting to watch
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Post by guyatacomputer - NE St. Peters on Jul 20, 2019 17:59:06 GMT -6
It isn’t allowed to be this hot for the rest of summer! So there! If only it were that easy |
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Post by cozpregon on Jul 20, 2019 17:59:52 GMT -6
Chariton IA airport had 60mpn wind with that
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Post by Lovableweatherguy TROY,MO on Jul 20, 2019 18:01:42 GMT -6
That mcs is heading right for the metro. If it survives.
Has some 14*C 700 temps to fight thru... but it will be interesting to watch
I looked at this about 20 mins ago and wondered the same thing. |
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Post by Snowstorm920 on Jul 20, 2019 18:08:30 GMT -6
SPC thinks that MCS will continue into the evening and are preparing to issue a watch downstream
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Post by cozpregon on Jul 20, 2019 18:10:35 GMT -6
Has some punch 61 mph Ottumwa
KOTM 210000Z AUTO 34029G53KT 1 3/4SM +TSRA SQ FEW019 FEW033 BKN048 23/19 A2988 RMK AO2 PK WND 34053/2356 LTG DSNT ALQDS RAB2357 TSB2356 P0013 T02330194
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Post by demerson- Fletcher MO on Jul 20, 2019 18:29:26 GMT -6
I hope it does and soon. My house won’t go below 82.
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Post by Lovableweatherguy TROY,MO on Jul 20, 2019 19:25:08 GMT -6
Looks like the severe threat has diminished (no current warnings), but it still looks fairly healthy and trucking south.
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Post by guyatacomputer - NE St. Peters on Jul 20, 2019 19:26:12 GMT -6
Still holding together. Might even be getting wider and expanding west.
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Post by BRTNWXMAN on Jul 20, 2019 19:28:27 GMT -6
SPC thinks that MCS will continue into the evening and are preparing to issue a watch downstream I'd be surprised if that survives the trip across MO with the toasty mid-level temps, nebulous forcing and waning instability...but it does seem to be accelerating towards the region. |
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Post by guyatacomputer - NE St. Peters on Jul 20, 2019 19:45:56 GMT -6
Nothing for us yet. But they have put a chance of storms in to the forecast for tonight as far south as Pike County, IL
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Post by cozpregon on Jul 20, 2019 19:48:42 GMT -6
SPC thinks that MCS will continue into the evening and are preparing to issue a watch downstream I'd be surprised if that survives the trip across MO with the toasty mid-level temps, nebulous forcing and waning instability...but it does seem to be accelerating towards the region. Cold pool setting up may be enough to make it this far south |
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Post by unclesam6 on Jul 20, 2019 20:05:34 GMT -6
what a headache.
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Post by BRTNWXMAN on Jul 20, 2019 20:07:05 GMT -6
I'd be surprised if that survives the trip across MO with the toasty mid-level temps, nebulous forcing and waning instability...but it does seem to be accelerating towards the region. Cold pool setting up may be enough to make it this far south Yeah, it does have that going for it...We've seen strong complexes and bows survive warm mid-level temps before when then get some momentum. |
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Post by demerson- Fletcher MO on Jul 20, 2019 20:29:00 GMT -6
Looks like it’s trying to move/develop more west. East side may miss this one if it makes it here.
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Post by Lovableweatherguy TROY,MO on Jul 20, 2019 20:30:11 GMT -6
Looks like Central MO might get it worse if this bow keeps tracking south.
Illinois might miss out? Almost looks like it is starting to track more south southwest?
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Post by Lovableweatherguy TROY,MO on Jul 20, 2019 20:30:50 GMT -6
Looks like it’s trying to move/develop more west. East side may miss this one if it makes it here. I was just saying the same thing. Glad I'm not the only one that noticed that. Lol |
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Post by cozpregon on Jul 20, 2019 20:57:57 GMT -6
Water vapor looks good... so no reason it won't make it thru. Does look like the metro is going to be on the east edge.  |
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Post by WEAXWATCHER on Jul 20, 2019 21:04:38 GMT -6
I watered my garden... for two hours. No reason it wont rain IMBY now...
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Post by nascarfan999 on Jul 20, 2019 21:24:16 GMT -6
Looks like it’s trying to move/develop more west. East side may miss this one if it makes it here. I was just saying the same thing. Glad I'm not the only one that noticed that. Lol Forget Illinois, I think this may miss then entire metro to the west should it hold together. |
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Post by guyatacomputer - NE St. Peters on Jul 20, 2019 21:59:47 GMT -6
Looks to be picking up forward speed, now. Just so it doesn't knock out power for anyone. Too darn hot for that.
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