Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sat Dec 24 2022 15:22:54

AWUS01 KWNH 241522
FFGMPD
ORZ000-WAZ000-242200-

Mesoscale Precipitation Discussion 1169
NWS Weather Prediction Center College Park MD
1022 AM EST Sat Dec 24 2022

Areas affected...western Washington State

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

Valid 241514Z - 242200Z

Summary...Rain rates should increase over the next 2-4 hours
across the Olympic Peninsula and adjacent areas of southwestern
Washington, leading to localized excessive runoff and
urban/low-lying flood potential.

Discussion...Radar and satellite imagery indicate a fairly robust
axis of precipitation over northeastern Pacific waters that should
make landfall along the western Washington coastline over the next
1-2 hours.  The axis of precipitation actually has embedded, more
robust convective elements (evidenced by recent lightning strikes
offshore) and is coincident with a marked increase in Integrated
Water Vapor Transport values (appraoching or exceeding 1000 kg/ms)
depicted by operational forecast guidance.  MRMS-estimated
rainfall rates are already in the 0.2-0.5 inch/hr range just north
of Aberdeen, WA, and as precipitation spreads inland, rates
approaching 0.75 inch/hr cannot be ruled out especially in
terrain-favored areas.

Current trends suggest that about a 5-hour window of heavier
rainfall/flood potential existing between 16-21Z today.=20
Thereafter, models suggest weakening IVT values as an approaching
cold front makes it to the coast and wind fields aloft weaken.=20=20=20
The heavier rainfall should promote urban and low-lying areal
flood/flash flood potential, which could also be exacerbated by
ongoing snow melt due to increasing surface temperatures.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7NLWFECQ4loCfItG0xPaawYA-ICsG-j_ICgbYDpLUyZ4n5r_GQQspqhRFmU6hOj2egsJ=
pW0Y6QEwcVXN0IkVramWPYU$  for graphic product...

ATTN...WFO...PQR...SEW...

ATTN...RFC...NWRFC...NWC...

LAT...LON   48402206 48042166 47382168 46392200 45812249=20
            45892301 46132390 46352408 46682410 47442435=20
            48142478 48362461 48262334 48252268=20

=3D =3D =3D
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.

--- SBBSecho 3.14-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.