Flood Potential Multiarea
From
Mike Powell@618:250/1 to
All on Sat Jun 28 10:41:00 2025
AWUS01 KWNH 281317
FFGMPD
TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-281900-
Mesoscale Precipitation Discussion 0538
NWS Weather Prediction Center College Park MD
917 AM EDT Sat Jun 28 2025
Areas affected...Southeast MO...Northeast AR...Western
TN...Western KY...Southern IL...Southern IND...
Concerning...Heavy rainfall...Flash flooding possible
Valid 281315Z - 281900Z
SUMMARY...Highly efficient pulse convection with sub-hourly 2"
totals and eventual broader downdrafts/cell mergers that pose an
isolated total to 3" and localized possible flash flooding.
DISCUSSION...Regional RADAR and GOES-E conventional imagery loops
depict developing convective clusters across the central MS Valley
into the Lower Ohio River Valley. WV loop and RAP analysis shows
sharp upper-level ridge and rapid directional/divergent flow aloft
to support weak but multi-directional outflow to support stronger ascent/updraft strength. At the lower levels, solid 15-20kt
solidly confluent 850mb flow through the Lower Ohio Valley
supports convergence of very deep moisture/narrow skinny profiles
with modest but sufficient instability (1000 J/kg of CAPE). Total
PWats over 2" and vertical flux convergence will allow for highly
efficient warm cloud processes (12-13Kft depth); but with weak
shearing/tilting of updrafts, downdrafts should collapse downward
likely resulting in focused totals up to 2" in less than 30-60
minutes. Further rounds of thunderstorms will be generated along
outflow boundaries; so with each cycle the potential for broader
updrafts increases with some potential for mergers or expansion
over areas that were hit with prior rounds suggesting an isolated
spot of 3" is possible.
Hydrologically, the area has been above normal in rainfall and
soil saturation in most locations in the MPD area. FFG values of
2"/hr seem reasonable and may be exceeded, suggesting widely
scattered incidents of localized flash flooding is possible.
Gallina
ATTN...WFO...ILX...IND...LMK...LSX...LZK...MEG...PAH...SGF...
ATTN...RFC...KRF...MSR...ORN...TIR...NWC...
LAT...LON 39358687 39208590 38388561 37658621 36748804
35128929 35289193 37299188 38048995 38768825
= = =
AWUS01 KWNH 281418
FFGMPD
MOZ000-ARZ000-OKZ000-KSZ000-281915-
Mesoscale Precipitation Discussion 0539
NWS Weather Prediction Center College Park MD
1018 AM EDT Sat Jun 28 2025
Areas affected...Northeast OK...Southwest MO...Northwest AR...
Exteme Southeast KS...
Concerning...Heavy rainfall...Flash flooding possible
Valid 281415Z - 281915Z
SUMMARY...Small slowly decaying MCC giving way to new slow
moving/efficient thunderstorms along unstable edges.
DISCUSSION...GOES-E 10.3um IR and regional RADAR mosaic depict a
smaller than average MCC with well defined MCV crossing out of SE
KS with the outer banding feature continuing to maintain on
stronger than forecast southwesterly warm air advection. AMV/RAP
analysis suggests a 300mb 50+kt jet speed max crossing out of
central KS northeastward, exposing favorable right entrance ascent
and favorable outflow to maintain and due to internal convection,
slightly enhance the MCV. This has also aided a solid south to
southwest 30kt inflow which has been orthogonal to the trailing
banding feature resulting in continued development. Initial
clusters near Tulsa have kicked some outflow southwestward and
visible imagery shows bubbling Tcu along the upwind instability
axis where MUCAPE values remain about 1500-2000 J/kg but are only
uncapped in the vicinity of the isentropic ascent.
Downstream, weak low level stratus appears to be burning off and
increased insolation is helping to bolster surface to boundary
layer heating across the high low level moisture environment
between the small MCC and the thunderstorm activity spurred by
downstream confluence in the MS/OH River Valleys. CIRA LPW layers
show area of concern remains the core of nearly all layers of
moisture with overall totals exceeding 2" and with deep layer warm
cloud processes (13-14Kft), will support efficient rainfall
production (especially where WAA/isentropic ascent is greatest)
with 2-2.5"/hr possible.
Slow deep layer flow given the MCC ciruclation is slowly to the
east and crossing into recently saturated (higher relative soil
moisture ratios into the mid to upper 60%) across the Ozark
Plateau. Combined with naturally lower FFG values due to the
complex terrain and low water crossings, the potential for
exceedance of FFG is higher and with spots of 3-4" totals suggest
it possible for scattered incidents of flash flooding to occur.
Gallina
ATTN...WFO...ICT...LZK...SGF...TSA...
ATTN...RFC...KRF...ORN...TUA...NWC...
LAT...LON 37999355 37789289 37439209 36719204 35639212
35109266 35119365 35299443 35429552 35789639
36679662 37109592 37329565 37529532 37759484
$$
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