Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Jul 24 2024 20:47:33

AWUS01 KWNH 242047
FFGMPD
SCZ000-FLZ000-GAZ000-ALZ000-250245-

Mesoscale Precipitation Discussion 0720
NWS Weather Prediction Center College Park MD
446 PM EDT Wed Jul 24 2024

Areas affected...portions of south-central AL/GA/SC

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

Valid 242045Z - 250245Z

Summary...Scattered tropical downpours with hourly totals of 1-3"
will result in localized totals of 3-6". Scattered instances of
flash flooding are likely.

Discussion...Convection is proliferating across portions of the
Southeast this afternoon, in the vicinity of a weak surface low
pressure center and associated quasi-stationary front/trough.
Overall convection remains somewhat disorganized, given a lack of
deep layer shear to tilt the updraft/downdraft, but some low-level
moisture transport/convergence (most prominently at 700 mb) has
begun to orient multi-cell clusters into more linear segments
across southeast AL into southwest GA (nearest to the surface
low). As ample tropical moisture is in place (with precipitaible
water values of 2.2-2.5", near max moving average and record
levels, per SPC sounding climatology) MRMS estimates have
indicated localized hourly totals of 1-3" (but mostly
non-repeating given the scattered coverage and the limited
longevity of individual updrafts). As the afternoon and evening
progresses, localized totals will start to add up as these linear
segments eventually affect some of the same areas from earlier
(with some limited training even possible in southeast AL, near
the low center). This will likely result in localized totals of
3-6", which should overwhelm FFGs of 3.0-4.0" (over a 3 to 6 hour
period). While locations farther north and east (into central GA
and south-central SC) are not as likely to realize the same
repeating and training trends, the FFGs are meaningfully lower
within the Piedmont (to the north of the fall-line) with 1-hr and
3-hr thresholds of 2.0" and 2.5" (or less), respectively. Given
the observational trends (and supporting hi-res model data, as
HREF 40-km neighborhood probabilities for 6-hr FFG exceedance
range from 20-50%), scattered instances of flash flooding are
considered likely.

Churchill

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!5StQnYiNvzR-bJRe7vwqnHPnqiSKXbBqL8AYYDG6HrJQgud2YYnwLPzgfpJBP8izHrQb=
3zaryQyQVLgS1IQqOm8vBUQ$  for graphic product...

ATTN...WFO...BMX...CAE...CHS...FFC...GSP...JAX...MOB...TAE...

ATTN...RFC...SERFC...NWC...

LAT...LON   34218138 33978047 33008055 32428157 31178193=20
            30988256 31428352 31528454 30828617 31038802=20
            32128734 33108596 33928448 33988284=20

=3D =3D =3D
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