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Spring and Summer thread for the Mountains


Met1985

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SREF now showing close to 3" of precip on avg. at KAVL for the up coming event.  With the winds whipping already, I think WNC could find itself in a mess tomorrow not only with flooding, but with trees falling due to soft soil.  These are the type events where mudslides occur, I hope Friday we aren't talking about another large one for the WNC area.

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SREF now showing close to 3" of precip on avg. at KAVL for the up coming event.  With the winds whipping already, I think WNC could find itself in a mess tomorrow not only with flooding, but with trees falling due to soft soil.  These are the type events where mudslides occur, I hope Friday we aren't talking about another large one for the WNC area.

Rule of thumb is 5 inches of rain in 24 hours as the threshold for significant mudslides so I think will be okay since amounts that exceed that will be very localized. My mtn is definitely mudslide prone and it appears from evidence provided by bent tree trunks that a slow motion slide might already be occurring on the very steep North side of the ridge.

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Well the event was horribly modeled again. While it did rain, amounts around the Asheville area look 1-1.5" in the last 24 hours. Some spots had 2-2.5", but those look far more rare.

I hope NASA got good data and can figure out why this event fell quite short of modeled QPF.

Sent from my iPhone using Tapatalk

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Well the event was horribly modeled again. While it did rain, amounts around the Asheville area look 1-1.5" in the last 24 hours. Some spots had 2-2.5", but those look far more rare.

I hope NASA got good data and can figure out why this event fell quite short of modeled QPF.

Sent from my iPhone

 

Looks like about a maximum of 3 to 3.5" from Southern Haywood County to Lake Toxoway to Highlands area.  With the event winding down-I doubt additional amounts will exceed an inch.

 

I suspect the same problem that has plagued events over and over again in this area..how models handle convection along the Gulf Coast. For some reason-convection down there keeps on over performing and disrupts downstream inflow. (I note a rather modest inflow of only 25 to 30 knots currently which generally isn't sufficient for high end events.)

 

Due to high winds on the mtn top last night and horizontal rain-rainfall readings appear highly suspect. For instance-the disdrometer rainfall algorithms are showing rainfall accumulation several times higher at the sheltered base of the mtn than at the top despite NOXP radar data showing overall higher returns as one would expected occurring on the ridges. There is one rain gauge equiped with a rain shield but data from that isn't available online. 

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Neat Info Mike. Maybe next time your up there take a few photos of it. If it ever does become larger, it would be cool to have a before and after shot.

 

Here's is an example of what I'm talking about regarding landslides and bent trees.

 

Good helpful link can be found here: 

 

http://www.geology.enr.state.nc.us/Landslide_Info/Landslides_main.htm

 

Note-the reason why Duke U/NASA had picked the Haywood County area is due to the frequency of deadly mudslides in the Maggie Valley vicinity which is immediately downstream from my location. They hope to be better able to predict them in the future combining all available data sources into one package.

post-9361-0-65206100-1400148880_thumb.jp

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Well the event was horribly modeled again. While it did rain, amounts around the Asheville area look 1-1.5" in the last 24 hours. Some spots had 2-2.5", but those look far more rare.

I hope NASA got good data and can figure out why this event fell quite short of modeled QPF.

Sent from my iPhone

 

 

I think I would let the event complete itself before declaring it as "horribly modeled". Most QPF projections that I have seen were through at least the 21z to 0z Friday range. Plus if you look at radar estimates for the Southern escarpment and down into the Upstate and Northeast GA, that's far from being a complete bust.

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Looks like about a maximum of 3 to 3.5" from Southern Haywood County to Lake Toxoway to Highlands area.  With the event winding down-I doubt additional amounts will exceed an inch.

 

I suspect the same problem that has plagued events over and over again in this area..how models handle convection along the Gulf Coast. For some reason-convection down there keeps on over performing and disrupts downstream inflow. (I note a rather modest inflow of only 25 to 30 knots currently which generally isn't sufficient for high end events.)

 

 

 

I'm not sure Gulf Coast convection can be blamed on this occasion. The front edge of the precip shield was putting down plentiful rates overnight due to the high PWAT's. This may be more a case of classic model bias of hanging up areas of convergence along the spine of the Apps.

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I think I would let the event complete itself before declaring it as "horribly modeled". Most QPF projections that I have seen were through at least the 21z to 0z Friday range. Plus if you look at radar estimates for the Southern escarpment and down into the Upstate and Northeast GA, that's far from being a complete bust.

Disagree. A quick check of radar shows, as Mike said as well, the event is winding down.

I'm glad we didn't get 3-5" of rain here in Buncombe County. Nobody needs the headaches associated with that. But, from a QPF distribution standpoint, the models were off, generally calling for more rain than what actually fell.

Perhaps it wouldn't be such a deal if the models had not missed the previous event as well (End of April). We all know it's tough forecasting in the mountains and the models seem to have as much difficulty as forecasters do. Lots left to learn all around!

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Just got home and we have a total so far at 1.71 inches of rainfall. Not bad and by the sounds of it there is suppose to be more to develop later this afternoon but not sure if that is going to be East or West of us. Not the big totals being advertised but still not that bad. So fat this week we are right at about 3 inches so not bad at all.

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Here's is an example of what I'm talking about regarding landslides and bent trees.

 

Good helpful link can be found here: 

 

http://www.geology.enr.state.nc.us/Landslide_Info/Landslides_main.htm

 

Note-the reason why Duke U/NASA had picked the Haywood County area is due to the frequency of deadly mudslides in the Maggie Valley vicinity which is immediately downstream from my location. They hope to be better able to predict them in the future combining all available data sources into one package.

 

The NC landslide mapping program did some excellent work and those maps are worth checking out.  On a side note, the NC legislature shut down the program because in their words, it might lead to regulation. 

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I think I would let the event complete itself before declaring it as "horribly modeled". Most QPF projections that I have seen were through at least the 21z to 0z Friday range. Plus if you look at radar estimates for the Southern escarpment and down into the Upstate and Northeast GA, that's far from being a complete bust.

Maybe mby was lucky - I was up til well after midnight with my dog cos of the thunder and lightning. Woke to nearly 4" of rain this morning (3.92). It absolutely poured last night around here at least (it's about time lol)

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We have picked up another tenth of an inch bringing storm total to 1.80 inches so far. Also the temps here have fallen to 50 degrees with a still West wind.

 

Highest total that I could find was at Lake T. with 4.24".   Cold air is pouring in now..temps to drop to near freezing on the mtn tops.

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Highest total that I could find was at Lake T. with 4.24".   Cold air is pouring in now..temps to drop to near freezing on the mtn tops.

Ya temps are really dropping and going to be a shock to the system come tomorrow morning and especially during the day when highs will only be in the 50s. We are still getting steady rains on and off here.

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Well the event was horribly modeled again. While it did rain, amounts around the Asheville area look 1-1.5" in the last 24 hours. Some spots had 2-2.5", but those look far more rare.

I hope NASA got good data and can figure out why this event fell quite short of modeled QPF.

Sent from my iPhone

 

A TON of data was indeed gathered from yesterday's storm.  In addition to all the ground based instrumentation(including a very cool ACHIEVE program instrumentation center in Maggie Valley), they put in numerous racing track high altitude flight paths over the Haywood County area and points to the SE to near the location of the NPOL radar site.

 

Here is a snippet of a brief comment that had about yesterday' storm: "..The precipitation forecast did not verify as the frontal precipitation developed into a squall line that, combined with a progressive short wave, propagated east and caused the back side of the precipitation to deteriorate faster than forecast.  This will be a good case to study how the structure of this system differed from progged."

 

The NOXP was active almost the entire time-the crew is worn out and is taking today off.  Reading through the log book..very cool.

 

An example below..they appear to be discussing the echos over my mtn top which is located on the Jackson/Haywood county line.

 

 

0122

The edge of the precip shield had entered Jackson County.  Some higher reflectivity echoes (over 60 dBZ) are forming right ahead of the shield closer to the Jackson/Haywood county line.

0132

Echoes on the Jackson/Haywood line are pulsing but are being overrun by the main precip shield.  Over 60 dBZ now noted up to 5.1 degrees.

0144

A NW to SE oriented line of 60 dBZ echoes moving due north are entering into Jackson & Transylvania counties.

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