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5/18/20 - 5/23/20 Upper Low Flooding & Severe Threat

Myfrotho704_ said:
This set up sucks for thunderstorms north of CLT, boundary separating SBcape/MUcape just can’t move north
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Yeah it's going to struggle both synoptically & on a mesoscale level. Strong synoptically forced cold air damming being reinforced in-situ by clouds & precipitation certainly will make it tough for that boundary to get beyond Charlotte.
 
Webberweather53 said:
Yeah it's going to struggle both synoptically & on a mesoscale level. Strong synoptically forced cold air damming being reinforced in-situ by clouds & precipitation certainly will make it tough for that boundary to get beyond Charlotte.
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Yep exactly, I have hope in Friday since the ULL will break down and move north and basically just turn into a little weakness, and heights will build around here allowing instability to recover, hoping for a few good shots before I go back to work next week
 
Figure I post here but tropical tidbits has an app now I recommend for those wanting model data for this event.
 
God wish that Charlotte air would move north its 40s with wind and drizzle. Feels like ICE. Still not much measurable rain.
 
BirdManDoomW said:
God wish that Charlotte air would move north its 40s with wind and drizzle. Feels like ICE. Still not much measurable rain.
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Bright side the odds of a May like this happening again in our lifetime ( well any given year) are very low as we are pushing the envelope of the coldest possible , as in all time coldest possible temps this time of year. So next year my memory of this will be gone and I can bask in a normal 80 degree May day, and go swimming, and barbeque .

We need to rid ourselves of the super cold water NE of NC so the eastern part of the state can shake this crap off! Montreals 10 day is warmer than Raleigh I kid you not.
 
1589921521926.png


Mesoscale Precipitation Discussion 0222
NWS Weather Prediction Center College Park MD
447 PM EDT Tue May 19 2020

Areas affected...western NC and in the vicinity of the NC/SC
border

Concerning...Heavy rainfall...Flash flooding possible

Valid 192045Z - 200230Z

Summary...The threat for flash flooding will expand eastward along
the NC/SC border through the remainder of the afternoon into the
evening. Slow moving storms could produce localized rainfall rates
between 2-3 in/hr and 6 hour totals in excess of 4 inches.

Discussion...20Z surface observations placed a quasi-stationary
front extending ESE from a surface low near LQK, with a cold front
arcing southward from the low into southern SC and coastal GA.
Scattered thunderstorms, some slow moving, were in place along
either side of the quasi-stationary boundary while a few
thunderstorms were tracking northeastward ahead of the cold front
at a quicker pace. Precipitable water values remain near 1.5
inches near the Coastal Plain with lower values upstate and while
instability is estimated to have decreased across western NC with
warming cloud tops on IR imagery, 850 mb winds remain at least 30
kt perpendicular to the terrain, helping support a favorable
upslope component where several inches of rain have already fallen
over the past 24 hours.

Short term forecasts from the RAP show that upslope flow magnitude
will maintain or slightly increase in intensity into the evening
across western NC as the main closed low over KY/TN continues to
drift southeastward. An additional 1-2 inches of rain can be
expected through 02Z from the Piedmont into southeast facing
slopes of the Appalachians. Given saturated soils from recent
heavy rain, additional flash flooding or flooding will be possible
with further reductions in instability.

In the vicinity of the NC/SC border, the threat for flash flooding
will increase over the next couple of hours as storms developing
within the warm sector, characterized by over 1000 J/kg MLCAPE,
track toward the quasi-stationary boundary which will serve as a
focus for strong low level convergence beneath diffluent flow in
the upper levels. Relatively slow storm movement is expected near
the stationary front with ordinary and organized storm vectors
ranging from 5 to 15 kt. While the threat should remain limited in
scale, storm mergers and slow movement of thunderstorms could
support rainfall rates between 2-3 in/hr with storm totals in
excess of 4 inches through 02Z.
 
I’m quite curious to see what tonight brings in North Georgia. The 3km NAM and HRRRv4 are showing a nice 1-2 inch swath of rain over parts of North Georgia especially those Northeast of Atlanta.

It looks like the eventual “death band” is going to get its beginnings over us and slowly push through the state tonight and tomorrow morning as the upper low swings through. The 3km NAM and HRRRv4 actually have my area under it for about 3-5 hours over the course of the early-mid morning hours.

Since I got nothing better to do, I might just go to bed early tonight and wake up really really early tomorrow morning to see what happens. Of course if I do that then I probably won’t get a drop. Lol
 
3.5 in the bucket and models with a whole lot more coming. This things needs to do something different than what is forecast. These totals from the 18z 3k into the up-slope areas of the blue ridge are incredible considering what has already fallen. The only good thing is it seems to be from persistent moderate rain here over the next 60 hours or so vs extremely heavy rain in a short period.
1589924702105.png
 
Looks like a band is trying to form once again along the I-77 corridor down in the Midlands. Looks like once again, if you are within 50 miles 77, it's about to get really, really wet.
 
Can see that boundary that’s dividing surface based cape from zero north of it to 500+south of it 6ECC1590-D68E-4D71-8366-E00DCE61E26E.png
 
Anybody got the 18z Rgem totals? Tropical Tidbits seems to be having script problems again.
 
SD said:
Not on pivotal either. Probably collapsed on itself with the firehose tomorrow
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I am surprised at how hard it's raining under this little skinny line. Imagine if the echos were yellow or orange! And the wind is blowing too.
 
Looks like wedge is winning tonight. Radar looks pathetic minus some heavy showers near Columbia SC. I was expecting more than drizzle. Some pavement is dry cold.
 
BirdManDoomW said:
Looks like wedge is winning tonight. Radar looks pathetic minus some heavy showers near Columbia SC. I was expecting more than drizzle. Some pavement is dry cold.
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A lull was always anticipated for the area. And those "heavy showers" are going to translate into a pretty good band later tonight. As far as the wedge is concerned, that was always a guarantee for this system. It's only going to increase totals, especially as the cut off low moves south tonight. You always repeat the same things as if it's a shocker. It's Tuesday, this system is supposed to hang around till Friday. Stop being so pessimistic and relax. We're getting some good rainfall totals without the threat of a major outbreak.
 
BirdManDoomW said:
Looks like wedge is winning tonight. Radar looks pathetic minus some heavy showers near Columbia SC. I was expecting more than drizzle. Some pavement is dry cold.
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I am very thankful for this period of runoff and drying! Already over 4 inches for me and i really needed this lull. Also, feels like fall again, another bonus!
 
Radar returns have been unimpressive all day yet we’ve clocked 1.14” in Raleigh. I call this Hilo rain. Like being on the windward slopes of Hawaii where it just sort of constantly precipitates under the radar beam as opposed to discrete showers and you somehow end up with 2”-3” day in day out.
 
Congrats to Mount Airy NC for gusting to 43 mph today! So cold and windy. Mostly a good day other than drizzle.
 
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