AWUS01 KWNH 041233
FFGMPD
ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-041831-

Mesoscale Precipitation Discussion 0118
NWS Weather Prediction Center College Park MD
832 AM EDT Fri Apr 04 2025

Areas affected...Eastern OK...Western and Northern AR...Southern MO

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

Valid 041231Z - 041831Z

SUMMARY...Organizing clusters of heavy showers and thunderstorms
will pose at least some concern for pockets of flash flooding
going through midday.

DISCUSSION...The early-morning GOES-E WV suite shows a vigorous
mid-level trough gradually ejecting east out into the southern
High Plains which is interacting with a moist and unstable airmass
surging northward up into the Arklatex region and broader lower MS
Valley region along with proximity of a quasi-stationary front. A
strong southerly low-level jet of 30 to 40+ kts is overrunning
this front which is yielding substantial warm air
advection/isentropic ascent and a nose of elevated instability up
across areas of eastern OK, northern AR and southern MO.

Already there is a large cluster of strong to severe thunderstorms
impacting especially northeast OK and northwest AR where very cold
convective tops to about -75 C are noted. The convection is being
aided by strong kinematics with strong effective bulk shear
parameters (50 to 60+ kts) in place coupling with the nose of
elevated instability with MUCAPE values of 1000 to 2000+ J/kg.

This convection is expected to remain well-organized through the
midday time frame with the convection likely becoming more
pronounced eventually into areas of southern MO, but with
additional development impacting areas of eastern OK and western
to northern AR going into the early afternoon hours. This will be
supported by some further strengthening of the low-level jet
(reaching as high as 40 to 50 kts) up across eastern OK and
western AR by early this afternoon ahead of the upstream height falls.

The aforementioned front will be lifting north as a warm front
with time, and this coupled with proximity of an inverted surface
trough poleward of the front will yield substantial low-level
convergence and forcing for convection. While there will be a
well-defined severe mode to the convection over the next several
hours, there will be sufficient levels of heavy rainfall that
pockets of flash flooding may begin to materialize. This will be
aided by 1 to 2 inch/hour rainfall rates and some rainfall totals
through 18Z (1PM CDT) of as much as 2 to 4 inches. The more
sensitive locations for runoff concerns should tend be over the
Ozark Plateau. However, there will also be urban runoff
considerations for flash flooding as well.

Orrison

ATTN...WFO...ICT...LSX...LZK...MEG...OUN...PAH...SGF...SHV...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC...

LAT...LON 37889085 37598974 36888920 36178999 35259323
34289432 34239542 34889594 35729655 36499615
37319440 37769268

$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)

AWUS01 KWNH 041513
FFGMPD
MOZ000-ARZ000-OKZ000-042000-

Mesoscale Precipitation Discussion 0119
NWS Weather Prediction Center College Park MD
1112 AM EDT Fri Apr 04 2025

Areas affected...Central to Northeast OK...Far Northwest
AR...Southwest MO

Concerning...Heavy rainfall...Flash flooding likely

Valid 041510Z - 042000Z

SUMMARY...Increasingly concentrated areas of very heavy shower and
thunderstorm activity is occurring over northeast OK, far
northwest AR and into areas of southwest MO. Flash flooding is
likely with locally considerable impacts over the Ozark Plateau
going through mid-afternoon.

DISCUSSION...Radar and satellite trends show an increasingly
concentrated southwest to northeast axis of very heavy showers and thunderstorms across portions of central to northeast OK,
northwest AR, and into southwest MO.

There are strong cell-training concerns setting up across this
region as the convection becomes aligned with the deeper layer
mean flow and also in close proximity to a well-defined 850/925 mb
convergence axis/front. Additionally, there is a well-defined
elevated instability gradient in place here with MUCAPE values of
as much as 1000 to 2000 J/kg. Facilitating the overall heavy
rainfall footprint continues to be the nose of a 30 to 40+ kt
low-level jet which should further strengthen a bit over the next
few hours which will yield stronger moisture transport into the
region for convective sustenance and also enhanced rainfall rate potential.

Rainfall rates of as much as 1.5 to 2.5 inches/hour will be
possible with the stronger storms, but with increasingly
well-established cell-training concerns, there may be as much as 4
to 6 inches of rain that occurs by mid-afternoon. None of the
current 12Z HREF guidance, nor the recent HRRR solutions, have a
good handle of the ongoing activity. Based on the
repeating/training signature of cooling convective cloud tops over
eastern OK, it appears that an organized level of convection will
certainly continue in the near-term.

Flash flooding has already started locally, but a more regional
and higher level of flash flooding impacts can generally expected
to occur soon, and especially for areas of the Ozark Plateau.

Orrison

ATTN...WFO...OUN...SGF...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NWC...

LAT...LON 37689214 37289195 36799275 35959445 35299551
34579645 34799679 35629628 36229565 36859477
37229404 37669286

$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)