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

------------=_1563642036-2024-2271
Content-Type: text/plain

AWUS01 KWNH 201700
FFGMPD
WIZ000-MNZ000-IAZ000-202020-

Mesoscale Precipitation Discussion 0642
NWS Weather Prediction Center College Park MD
1259 PM EDT Sat Jul 20 2019

Areas affected...Wisconsin, Northern Iowa, Southeast Minnesota

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

Valid 201620Z - 202020Z

Summary...Several rounds of thunderstorms may lead to areas of
heavy rainfall in excess of 2-3 inches and some flash flooding
across parts of Minnesota, Iowa and Wisconsin. This would be most
likely in parts of central Wisconsin which have already received
rainfall in excess of 1 inch in the past 24 hours.

Discussion...Several convective clusters were propagating from
west-to-east across the Upper Midwest around midday. These were
arranged in a sequence, and roughly 150mi apart. Given the
abundance of strong instability to the south of the ongoing
thunderstorms, and a band of stronger westerlies aloft just along
the periphery of the instability axis, it seems likely these
convective clusters/lines will continue to make steady progress to
the west. The relatively large spacing between the concentrated
areas of thunderstorms does not favor flash flooding, nor does the
progressive nature of the convection. However, these thunderstorms
may overlap with some areas that have already received heavy
rainfall in SE MN and C WI. That would be the most likely area to
receive flash flooding from the way the thunderstorms are
currently configured.

There is a chance that flash flooding could develop in areas
further to the south, if the trailing portions of convective lines
become oriented in a west-east fashion parallel to the storm
motion vector. Low-level winds around 925-850mb had a considerable
westerly component, and this may favor some backbuilding in any
such line segment (trailing a forward-propagating MCS, along the
S/SW flank of a cold pool). The atmosphere is also very moist
across the region, with some GPS-PW observations in excess of 2
inches (above the 99th percentile). The combination of deep
moisture and strong instability can lead to very high
instantaneous rain rates, which can compensate somewhat for faster
progression of the convective clusters. Therefore, flash flooding
will be possible, but there are some mitigating factors. The
greatest likelihood would be over SE MN and C WI where antecedent
conditions and recent rainfall would likely require less rainfall
to produce flash flooding.

Lamers

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

ATTN...WFO...ARX...DMX...DVN...GRB...MKX...MPX...

ATTN...RFC...NCRFC...

LAT...LON   44868896 44588749 42998778 42569028 42649288
            42919394 43679384 44259260 44619097


------------=_1563642036-2024-2271
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.
------------=_1563642036-2024-2271--

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