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Severe Threat 8/12-14, 2019

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#5
Day 1 outlook a bit different today. Level 3 threat farther south into VA, and a level 2 threat for half of NC and almost all of TN.

Sorry, I refuse to use the terms the SPC has anymore since they don't make any sense.

 

Myfrotho704_

It’ll make its own cold air
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#6
thing about today is while lapse rates wont impressive at all except for low level lapse rates, with large amounts of low level moisture and then drying aloft, theta-E advection will be extremely high, and surface based cape will be around 2500-5000 jkg, 20-35 kts of 500mb flow, and 10-25 kts of 0-3km shear/ tiny curved LLvL hodos may help storms organize and even develop mid level mesocyclones BEA051F4-35CB-47B6-B870-C5FC1574AD37.png 54FD5B39-7538-4F16-A92C-F3CF20A76FAB.png
 
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#7
thing about today is while lapse rates wont impressive at all except for low level lapse rates, with large amounts of low level moisture and then drying aloft, theta-E advection will be extremely high, and surface based cape will be around 2500-5000 jkg, 20-35 kts of 500mb flow, and 10-25 kts of 0-3km shear/ tiny curved LLvL hodos may help storms organize and even develop mid level mesocyclones View attachment 21589 View attachment 21590
dat DCAPE d'oh...
 
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#10
Watch probably coming out soon.



Mesoscale Discussion 1722
NWS Storm Prediction Center Norman OK
1100 AM CDT Tue Aug 13 2019

Areas affected...Portions of eastern TN...southwestern/southern
VA...and western/central NC

Concerning...Severe potential...Watch possible

Valid 131600Z - 131745Z

CORRECTED FOR TIME REFERENCES

Probability of Watch Issuance...60 percent

SUMMARY...A threat for strong/gusty winds capable of producing
isolated damage should increase this afternoon. Watch issuance is
possible by 18Z (2 PM EDT).

DISCUSSION...15Z surface analysis and visible satellite imagery
shows an outflow boundary from earlier convection has moved
southward into middle/eastern TN and southwestern VA. Storms have
recently begun to increase in coverage along this boundary as
daytime heating warms the boundary layer. A high precipitable water
airmass is in place along/south of this boundary across much of
eastern TN into southwestern/south-central VA and western/central
NC. As surface air temperatures warm into the 80s and 90s this
afternoon, low-level lapse rates will likewise steepen and
instability will increase. A belt of modestly enhanced mid-level
flow (around 30-40 kt at 500 mb) will overlie this region through
peak diurnal heating, with area VWPs showing the strongest winds
over southern VA gradually weakening into TN/NC. Strong/gusty winds
may occur as this enhanced flow aloft reaches the surface through
convective downdraft processes. Isolated damage from these winds
will be possible given the potential for some multicell clustering
as storms spread eastward through the early evening. Watch issuance
may be needed within the next couple of hours (by 18Z/2 PM EDT).
 

Myfrotho704_

It’ll make its own cold air
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#11
Man western NC, parts of SC/GA is thermodynamically set for intense downbursts, just gotta wait for the better shear to move in, wouldn't surprise me if a few storms had 70-80 mph microbursts with them 159AA1F4-70C4-4620-8E27-76CD925CC1A2.jpeg BF35D0DD-38CD-43D9-B381-175DF49091B2.jpeg
 
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#16
Might get a watch here, too.




Mesoscale Discussion 1724
NWS Storm Prediction Center Norman OK
0102 PM CDT Tue Aug 13 2019

Areas affected...Portions of south-central into southeastern
VA...central/eastern NC...and far northern SC

Concerning...Severe potential...Watch possible

Valid 131802Z - 132030Z

Probability of Watch Issuance...40 percent

SUMMARY...Some increase in a strong to locally damaging wind threat
should occur this afternoon. Watch issuance is possible.

DISCUSSION...Morning cloudiness and precipitation has hampered
destabilization so far this afternoon across southeastern VA.
Stronger instability is present across central NC where ample
diurnal heating of a very moist low-level airmass is contributing to
1500-2500 J/kg of MLCAPE. A line of storms along the TN/NC border at
18Z should continue eastward this afternoon, eventually reaching
south-central VA into central NC. Additional storm development may
occur ahead of this line across parts of central NC in a weak
low-level convergence zone based on latest observational and
short-term model trends. Relatively stronger low to mid-level
westerly flow is being estimated by KAKQ VWP in southeastern VA
compared to KRAX in central NC. Related effective shear magnitudes
are forecast to remain marginal across these areas through the
afternoon, likely no greater than 20-30 kt. Clustering of storms
into one or more loosely organized lines is possible, but is by no
means certain. Strong to locally damaging downdraft winds would be
the main threat given steepening low-level lapse rates. Watch
issuance is possible at some point this afternoon depending on
observational trends.
 
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#28
Getting some house shaking thunder now. And more storms to the west.

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE RALEIGH NC
522 PM EDT TUE AUG 13 2019

THE NATIONAL WEATHER SERVICE IN RALEIGH HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHERN ALAMANCE COUNTY IN CENTRAL NORTH CAROLINA...
SOUTHERN ORANGE COUNTY IN CENTRAL NORTH CAROLINA...
NORTHERN CHATHAM COUNTY IN CENTRAL NORTH CAROLINA...

* UNTIL 600 PM EDT

* AT 522 PM EDT, A SEVERE THUNDERSTORM WAS LOCATED 9 MILES SOUTH OF
GRAHAM, MOVING EAST AT 30 MPH.

HAZARD...60 MPH WIND GUSTS AND QUARTER SIZE HAIL.

SOURCE...RADAR INDICATED.

IMPACT...HAIL DAMAGE TO VEHICLES IS EXPECTED. EXPECT WIND DAMAGE
TO ROOFS, SIDING, AND TREES.

* LOCATIONS IMPACTED INCLUDE...
CHAPEL HILL, HILLSBOROUGH, PITTSBORO, SILER CITY, CARRBORO,
SWEPSONVILLE, CROSSWINDS BOATING CENTER, EFLAND, SNOW CAMP AND
CROSSWINDS CAMPGROUND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.
 
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#29
Actually looks like the sever warned storm went to the south of me, and what I am getting now is on the southern fringe of another storm. Just hearing some pretty loud thunder.
 
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