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Good Saturday morning to everyone!

Wow... how about those winds last night? That was something wasn't it? All of that weather was brought to you by a system known as a Mesoscale Convective System or MCS. In the summertime with the right setup, we can get in a NW flow situation that brings these systems to north Georgia and that's what happened during the overnight hours. The MCS originated over the high plains and traveled to Georgia on those NW winds.  It also appears that there might have been a wake low associated with the event, and I'm sure we'll hear more about that as the day goes on.

For Georgia, high winds and heavy rain were the main issues. There are LOTS of reports of trees down all across north Georgia. The winds woke me up with a loud roar around 2:20 am here in Gwinnett. It was so loud I had to get up and see what was the matter. Away to the window I flew like a flash, tore open the shutters and threw up the sash...        sorry... I got carried away. 🙂

In this radar image (current as of 8:13 am) you can see the MCS that moved through north Georgia is now near the coast, but notice a new one headed southeast toward Georgia, and that will be our next potential severe weather system.

Snap165-22.thumb.jpg.4a11f17974404d16d1534f70de861366.jpg

20190622_1223_khpx_BR_0.5-827am.thumb.png.437e46dbc01003f7364005b3b58cf117.png

 

Let's go to the Greenville SC NWS office for their thoughts for NE Georgia for today.

Quote

The next Corn Belt convective
complex is currently making its way toward the Ohio Valley and
should make steady progress toward the Mid-South and southern
Appalachians throughout the morning and into the afternoon within NW

flow regime. Short term guidance is not in the greatest of agreement
regarding the amount of destabilization that will occur ahead of
this approaching convection later today. However, a plume of steep
mid-level lapse rates (7-7.5 C/km) is expected to remain in place
across roughly the southern third of the forecast area through the
day, and we would expect at least moderate instability (i.e.,
2000-2500 J/kg sbCAPE) to develop in this area during the afternoon.

Elevated pops continue into this evening, with at least slight
chances continuing into the overnight, as yet another round of Great
Plains-originating organized convection cannot be ruled out.
As long as the MCS train keeps moving, severe weather will continue
to be a concern, primarily in the form of damaging winds, but the
steep mid-level lapse rates will also support a large hail threat,

esp across the Upstate and northeast GA

 

Let's also listen to the Atlanta NWS office with a little more detail. Again... the highlights are mine.

Quote

SHORT TERM /Today through Sunday/...
Active NW flow aloft will continue through Sunday. A nearly
stationary surface boundary will remain situated across the
Carolinas, extending into northern GA.

500mb analysis shows W/NW flow aloft across the CWFA on top of a
high centered across the Gulf. The models are progging the ridge to
start building across the central gulf coast, and starting to slowly
inch eastward today into early Sunday. The flow will turn even more
NW with several strong pieces of shortwave energy noted in the flow.
The current WV loop shows a second MCS gearing up over the Mid MS
Valley and drop SE in the flow. The MCS should impact portions of
the CWFA later today.


At the surface, the old boundary is providing focus for the upper
level energy. The MCS over the Mid Ms River valley will continue to
drop SE today. It may weaken somewhat as it approaches the CWFA
during the early part of the day, but do think additional storms
could fire up along the leading edge/outflow of the system during
the most unstable part of the afternoon. The atmos remains very
unstable, with abundant fuel for these types of systems. The main
storm mode overnight has been damaging wind gusts, but do think the
hail potential will increase with any system that moves through
during the afternoon/evening hours. Models are progging lapse rates
7.5-8 C/km. An isolated tornado cannot be ruled out either.


The high res models (and synoptic) models all struggle with these
types of systems. But experience says there should be a lull during
the early part of the morning, possibly into the very first hours of
the afternoon. But, convective activity will increase during the
afternoon, either with the MCS currently over the Mid MS valley or

out just out ahead of it. Storms should begin to diminish/weaken
during the mid evening and into the overnight. As in previous days,
the hi-res models are in disagreement with timing and placement of
any afternoon activity. Have tried to take a compromise for timing
but the wrf seems a bit more reasonable with coverage.

Models continue to prog some shortwave energy dropping southeast in
the flow for Sunday, so another round of storms are possible. Will
keep pops to scattered for now.

 

So just like yesterday, we will most likely see another round of heavy weather late this afternoon and evening. Remember to always have multiple methods of receiving weather information, especially while sleeping. 

I will be monitoring the next MCS and let you know how things are looking later today. 

forecast-22.thumb.jpg.2ba9c5504e19b92a8b86a16dcec23ed4.jpg

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I saw a tweet about yesterday’s system of the hurricane like similarities it had with outflow and such

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13 minutes ago, RickyD said:

I saw a tweet about yesterday’s system of the hurricane like similarities it had with outflow and such

I shared that on FB earlier. The system was able to evacuate air very efficiently, and that helped to maintain the strength.  

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Lost power around 2am in Buford... came back on around 7. It got steamy in the house to say the least! 

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mcd1195.gif.3471b4598cdfea005de52a2e7fce8769.gif

Mesoscale Discussion 1195
   NWS Storm Prediction Center Norman OK
   1201 PM CDT Sat Jun 22 2019

   Areas affected...South Carolina...portions of eastern
   Tennessee...southern North Carolina...and northeast Georgia

   Concerning...Severe potential...Watch likely 

   Valid 221701Z - 221900Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Thunderstorms are expected to increase in coverage and
   intensity through early afternoon, gradually developing into
   southeast-moving clusters of storms with a risk for damaging winds
   and isolated large hail.  A Severe Thunderstorm Watch will likely be
   needed prior to 18Z/2 pm EDT.

   DISCUSSION...a frontal boundary extends west from near the NC/SC
   border at 1630Z into a remnant convective system over eastern TN.  A
   separate diffuse outflow boundary extended across southern SC west
   across northeast GA. Downstream of the TN convective system,
   substantial diabatic heating of a very moist air mass (upper
   60s/lower 70s dew points) is underway.  The region lies beneath the
   eastern fringe of an EML that will contribute to strong
   surface-based instability this afternoon with SBCAPE in excess of
   2000 J/kg over much of the area.  

   As CINH continues to erode, thunderstorms are expected to
   develop/increase in coverage this afternoon near the aforementioned
   boundaries and along the leading edge of the convective system.  The
   combination of steep low-level lapse rates, water-loading in
   updrafts and mid-level drying evident on forecast soundings will
   result in a risk for damaging winds with the strongest storms. 
   Evolution towards southeast-moving clusters given 25-30 kts of
   northwesterly mid-level flow is expected with time resulting in
   corridors of more concentrated damaging wind risk.  The combination
   of strong low-level lapse rates and instability, boundary
   interaction and tendency for upscale growth with time suggests some
   potential for transient low-level circulations to develop, possibly
   resulting in a brief tornado.  Despite marginal deep-layer shear,
   the steep mid-level lapse rates will also contribute to isolated
   instances of large hail.

   Convective trends are being monitored and a Severe Thunderstorm
   Watch will likely be needed prior to 18Z.

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2 hours ago, Shannon said:

Lost power around 2am in Buford... came back on around 7. It got steamy in the house to say the least! 

I bet. We flickered but never went off. 

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mcd0480-22.gif.4d55e2ed9ecd00b7179033d9583907c8.gif

Mesoscale Precipitation Discussion 0480
NWS Weather Prediction Center College Park MD
316 PM EDT Sat Jun 22 2019

Areas affected...Northern AL...Georgia

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

Valid 221915Z - 230115Z

Summary...Pulse to loosely organized thunderstorms developing
along an old outflow boundary could pose a flash flood threat
given slower storm motions and multiple boundary interactions
through this afternoon.

Discussion...Regional radar mosaic this afternoon across Alabama
and Georgia showed two concentrated areas of pulse to loosely
organized thunderstorms, one over northern AL and another across
southeast GA. Both of these areas are likely enhanced due to a
residual outflow boundary from earlier convection.

With peak heating and dewpoints in the lower to middle 70s, more
than sufficient amounts of instability have developed with an axis
of 4000-5000 J/kg of SBCAPE oriented from AR through central
MS/AL/GA toward GA/SC coastline. Aloft, there are hints of
slightly lower heights, possibly due to the multiple lines of
convection rounding the top of the ridge over the southeast US,
and this may be aiding the development as well. Finally, latest IR
imagery from GOES-East shows rapidly cooling cloud tops as
convection continues to deepen/intensify.

Through late afternoon or early evening, convection is likely to
persist with the baggy low level flow leading to multiple boundary
interactions and regeneration. Some repeating rounds or nearly
stationary storms will be possible and this combined with a
seasonably high PW and more than sufficient instability, could
yield hourly totals in excess of 2" in places. The various hi-res
models paint two concentrated areas of higher QPF, one across
northern AL and possibly west-central GA and another along
southeast GA and potentially far southern SC. Both of these areas
could see totals 2-4" through 01z.

Antecedent conditions are mostly drier than normal across the
outlook area and this lowers the confidence in flash flooding
somewhat. However, given the potentially intense rates, slow storm
motions, and interactions along the residual boundary, some
localized flash flooding will be possible.

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