Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Nov 22 2022 17:12:08

AWUS01 KWNH 221712
FFGMPD
FLZ000-222310-

Mesoscale Precipitation Discussion 1128
NWS Weather Prediction Center College Park MD
1210 PM EST Tue Nov 22 2022

Areas affected...East-Central Florida Coast

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

Valid 221710Z - 222310Z

Summary...Localized flash flood threat increasing this afternoon
with highly efficient warm rain processes causing 1-3"/hr rainfall
rates within slow moving showers.

Discussion...Showers are increasing in coverage across the
east-central Florida coast this afternoon, as a surface trough of
low pressure remains anchored near the Treasure Coast and Space
Coast regions. The mesoscale environment is characterized by SB
CAPE of 1000-2000 J/kg, precipitable water of 1.9-2.2 inches (near
the max moving average per XMR sounding climatology), and
effective bulk shear of 25-35 kts. This rather impressive late
autumn environment is occasionally producing highly efficient
rainfall rates of 1-3"/hr, as evidenced by radar signatures
suggesting dominate warm rain processes (charactierzed by
relatively low reflectivity (Z) of 40-50 dBZ and differential
reflectivity (ZDR) of 1.0-1.5 dB collocated with relatively high
values of specific differential phase (KDP) of 1.0-2.5 deg/km,
suggesting low ice/hail content and high water content with
plentiful small, round droplets). While shower activity itself is
rather disorganized, easterly low-level winds of 5-10 kts are
resulting in slow storm motion with occasional repeating of these
high rainfall rates. This activity is expected to continue well
into the afternoon, with good agreement among high-resolution
guidance (HREF neighborhood exceedance probabilities for 3-hr QPF
> 3.0 inches reaching as high as 30-50%). Any instances of flash
flooding are expected to remain localized and primarily confined
to urban areas.

Churchill

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-BmZ4wkbk1irJRFkojxpwn1AXden_9wxfDtDRvALYP1ytU_RA3IN9y4oguK7sQyu_EVR=
qppsrGOJCdAzIDjdnYW-kXI$  for graphic product...

ATTN...WFO...MLB...

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

LAT...LON   29168056 29038028 28548004 27667978 27318005=20
            27268046 27468067 27998091 28538104 29038112=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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