MESO: Heavy Rain MWUS
From
Weather Alert@454:1/105 to
All on Mon Jun 13 16:54:00 2022
AWUS01 KWNH 131824
FFGMPD
WVZ000-OHZ000-KYZ000-INZ000-140000-
Mesoscale Precipitation Discussion 0350
NWS Weather Prediction Center College Park MD
222 PM EDT Mon Jun 13 2022
Areas affected...West-Central to Southeast IND...Southwest
Ohio...Northern Kentucky.
Concerning...Heavy rainfall...Flash flooding possible
Valid 131820Z - 140000Z
SUMMARY...Strong thunderstorms capable of very intense short-term
rainfall rates moving toward wetter soil conditions as complex
matures toward late evening. Isolated flash flooding becoming
increasingly possible.
DISCUSSION...Please refer to SPC MCD 1143 for convective
initiation setup indicating extremely unstable environment. As
for excessive rainfall, the southwest low level flow is 20-25kt at
85H and generally orthogonal to the strong temperature/instability
axis from Northern IL to Northern Kentucky which is unsurprisingly
aligned with highest moisture axis per CIRA LPW with sfc-85H
supporting .7-.8" and increasing mid to upper level moisture
upstream increasing from .2 to .4, which totals to about 2" across
northern IL into W-central IND. Given the broad moisture flux
convergence thunderstorms should have solid rainfall generation
efficiency supporting over 2"/hr rates.
Currently broad areas of individual cells are developing and are
generally slow moving providing short-term potential for 2"
totals, across areas of average soil saturation. Given the
development of convection to the inflow, short-term back-building
and training is possible especially across Ext E IL and W-Central
IND before the cells organize a bit further. Modest divergence
aloft and further expansion of convective cells should allow for
increasing organization toward a convective complex in the next
few hours across Central IND. While this will allow for increased
forward propagation reducing rainfall duration, it will
substantially increase moisture flux convergence along the leading
edge and support 2"/hr totals but likely to 1-2" in less than 30
minutes. This is concurrent with expected southeastward movement
into areas recently affected by 200-300% of normal rainfall over
the last week or two in SE IND/SW Ohio. Local FFG values less
than 1.5"/hr particularly along the I-75 corridor from Dayton to
Ohio are particularly susceptible to intense rain-rates and
excessive runoff even outside urban settings where 0-40cm are
running 80-95% per NASA SPoRT. Given unstable environment prior
to the developing squall line, a few smaller precursory cells are
possible which would further increase the potential for isolated
localized flash flooding as the line merges. HREF probability of
3"/3hrs reaches 10-20% between 21-00z over SE IND toward the
Cincinnati Metro/western & southern suburbs providing some
increased confidence in possible flash flooding even with expected
forward speeds of the complex.
Gallina
ATTN...WFO...ILN...IND...JKL...LMK...RLX...
ATTN...RFC...OHRFC...NWC...
LAT...LON 40428731 40428655 40198464 39388226 38348233
37698331 38378539 39238696 40008749
= = =
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)