BBS: TELESC.NET.BR
Assunto: MESO: Nws Weather Prediction Center College Park Md
De: COD Weather Processor
Data: Mon, 18 May 2026 00:26:33 +0000
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AWUS01 KWNH 180026
FFGMPD
MOZ000-IAZ000-KSZ000-NEZ000-180600-
Mesoscale Precipitation Discussion 0179
NWS Weather Prediction Center College Park MD
825 PM EDT Sun May 17 2026
Areas affected...Southeast NEB...Southwest IA...Northwest
MO...Central to Northeast KS...
Concerning...Heavy rainfall...Flash flooding possible
Valid 180025Z - 180600Z
SUMMARY...Training/Back-building cells at apex of dry slot will be
slow moving while higher moisture flux cells northward will track
through areas of recently saturated grounds with rates of 1.5"/hr
and spots of 2-3" totals, pose widely scattered incident or two of
flash flooding into early overnight period.
DISCUSSION...00z surface analysis depicts a very deep, but narrow
surface trough extending from a surface low in SE SD, southward to
a 993mb low just south of the central NEB/KS border at the nose of
an equally narrow but very dry slot; simultaneously, a strong
northern stream cold front is dropping southeastward from the low
resulting is a very strong surface to boundary layer flow with a
broad area of 20 to 30kts from the south slowly backing toward the
frontal zone. This results is a long axis of strong moisture flux
convergence, especially across SE NEB where Tds are in the high
60s, tipping toward the low 70s across the Missouri River into
IA/N MO. While the solid EML is well denoted in the CIRA LPW
850-700mb layer across much of this areas, return moisture
wrapped around the apex of the tight inverted trough, is pooled
along the approaching cold front. So while the steep lapse rates
are supporting MLCAPEs of 3000-4000 J/kd across E KS into SE NEB,
there is some entrainment of higher moisture and stronger
thunderstorms are starting to moisten the mid-layer profile and
overall rainfall efficiency is starting to increase and will do so
after sunset.
Coincident with the inverted trough is a tight 500-1000mb
thickness ridge the becomes a bit more divergent in isoheight
lines along and east of the trough axis. This supports reduced
forward propagation vectors, especially near the surface low and
south across central KS and with deep layer fairly unidirectional
flow from the SW, may allow for training/repeating across this
area while cells/clusters further north will start propagating
east-northeastward at a more reasonable rate across E NEB into IA.
Evaporative loss will limit extreme rates, though the moisture
flux on the 30+kt inflow should support 1.5"/hr with an
occasionally uptick to 1.75"+, and may be slightly higher due to
ingest of smoke particulates from the prairie fires in Clark and
Meade counties.
Northward in SE NEB and along the IA/MO border, the heavy rainfall
last evening has brought FFG values into a range (1-1.5"/hr
<2"/3hrs) that may be locally exceeded with the clusters moving
east, suggesting a scattered incident or two of flash flooding
will be possible through early overnight period. Southward across
central KS, the unidirectional steering and upwind propagation may
allow for increased residency; so while this area's soil
conditions are very dry, the prolonged nature of rainfall with
localized spots of 2-4" may also result in localized FF. (Note: a
backyard observation near Dorrance, KS in E Russell county saw
just below 2" in the last hour). So all considering, a few spots
of flash flooding are considered possible across the MPD area of
concern through the overnight period.
Gallina
...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!5IInHaJaZZMwD3wa0TaLpebr92Hz9Aevw48MwlnPPZbxy9I-twDjBNXJPhPeOPj8Va6D=
_El-L9tZjN8AHI9Tq73wSfU$ for graphic product...
ATTN...WFO...DDC...DMX...EAX...GID...ICT...OAX...TOP...
ATTN...RFC...KRF...MSR...TUA...NWC...
LAT...LON 42169490 42079412 41929340 41309302 40119334=20
39529611 38429803 38269948 38889946 39559824=20
40669796 41839753 42149622=20
=3D =3D =3D
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