This is a multi-part message in MIME format...

------------=_1563900283-2024-4488
Content-Type: text/plain

AWUS01 KWNH 231644
FFGMPD
VAZ000-NCZ000-SCZ000-232235-

Mesoscale Precipitation Discussion 0666
NWS Weather Prediction Center College Park MD
1238 PM EDT Tue Jul 23 2019

Areas affected...Northwest SC...NC...Southeast VA

Concerning...Heavy rainfall...Flash flooding likely

Valid 231635Z - 232235Z

SUMMARY...Showers and thunderstorms will become more numerous
across the southern Mid-Atlantic region over the next several
hours. Concentrated areas of heavy rainfall can be expected going
through the afternoon hours, and this should result in some areas
of flash flooding.

DISCUSSION...The latest surface analysis shows a cold front very
slowly advancing southeast across the southern VA and western NC.
Meanwhile, multiple waves of low pressure are seen advancing
northeast up along the front as an upper trough slowly digs down
across the TN Valley. In fact, the latest GOES-16 IR/WV imagery is
showing evidence of a baroclinic leaf over the southern
Appalachians as shortwave energy amplifies toward the base of the
trough and allows for some small scale backing of the mid-level
flow downstream over the Piedmont and portions of the coastal
plain.

This shortwave energy will be interacting with the front through
the afternoon as a very moist and increasingly unstable airmass
via strong diurnal heating pools up along and south of the
boundary. The latest RAP analysis already shows a pool of MLCAPE
values exceeding 2000 j/kg across central NC, and this moderate
instability will only grow over the next couple of hours with
additional solar insolation. The latest visible satellite imagery
has already begun to show an axis of agitated CU/TCU out ahead of
the front, and pockets of convective initiation are now underway
over central and northern NC. A broader area of convective
initiation is expected soon over a broader area and including
northeast NC and southeast VA after 18Z. Convection will also be
initiating and expanding in coverage farther to the southwest from
areas of south-central NC down into northwest SC out ahead of the
main cold front positioned to the west.

The 12Z HREF suite of hires model guidance is quite aggressive
with the rainfall potential this afternoon across portions of
central to northeast NC and into southeast VA. And all of these
models support the idea of organized and heavy convective rainfall
developing as the upstream wave of low pressure and supporting
shortwave advances northeast along the front. By 00Z this evening,
most of the latest hires guidance show low pressure near or
beginning to exit the Hampton Roads area of southeast VA which
will then allow for the heavy rainfall threat to begin to taper
off.

Given the high PWAT environment, with values of around 2 inches,
and the expectation of strong instability to evolve, the
convection will be capable of producing very high rainfall rates
of as much as 3 inches/hr. The 12Z HREF probabilistic output
suggests the area with the greatest likelihood of seeing this will
be the Hampton Roads area of southeast VA and to a lesser extent
down into northeast NC. However, the HRRR guidance tends to favor
the better support of this down across northeast NC.

Expect rainfall totals of as much as 3 to 5 inches of rain through
21Z, with additional rains likely going through 00Z. Areas of
flash flooding area likely given the very high rainfall rates and
the anticipated storm totals through the afternoon.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AKQ...CAE...GSP...ILM...MHX...RAH...RNK...

ATTN...RFC...MARFC...SERFC...

LAT...LON   37227620 37067581 36637566 35937590 35507660
            35187772 34987877 34458033 33908183 34218246
            34548252 34958224 35708178 36118110 36157988
            36467919 36757840 36917728


------------=_1563900283-2024-4488
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
------------=_1563900283-2024-4488--

--- SBBSecho 3.07-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)