343
AWUS01 KWNH 010654
FFGMPD
IAZ000-NEZ000-011245-

Mesoscale Precipitation Discussion 1043
NWS Weather Prediction Center College Park MD
252 AM EDT Mon Sep 01 2025

Areas affected...Eastern NE

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

Valid 010652Z - 011245Z

SUMMARY...A couple of slow-moving and locally training bands of
heavy showers are expected over eastern NE going through dawn.
Some areas of flash flooding will be possible.

DISCUSSION...The latest GOES-E WV suite shows a somewhat elongated
mid-level trough axis over the central Plains, with a couple of
embedded compact vort centers. One such vort center is nearly
stationary over eastern NE and has been fostering an uptick in
heavy shower activity over the last 1 to 2 hours.

The cloud tops with this convection are relatively warm/shallow
and suggestive of a warm rain environment that will be conducive
for more efficient rainfall processes for elevated rainfall rates.

On a small scale, there is a favorable corridor moisture
convergence wrapping up around the eastern flank of the vort
center, with an environment that is only modestly unstable. In
fact, the MUCAPE values are only about 500 J/kg.

Regardless, there is sufficient mid-level forcing/ascent working
in tandem with the low-level south to southeast flow and
instability for the convection to initiate and locally expand in
coverage. Some additional nocturnal contraction/tightening of the
low to mid-level circulation is expected over the next few hours
and this may help to further concentrate these smaller scale bands
of shallow-topped convection.

The rainfall rates will be capable of reaching 1 to 2 inches/hour
given the efficient environment, and with slow cell-motions and
cell-training concerns, some rainfall totals going through dawn
may reach as high as 3 to 4+ inches. The HRRR guidance is trending
gradually wetter across eastern NE, and the radar and satellite
trends would tend to favor these locally heavier totals
materializing.

Some areas of flash flooding will be possible across eastern NE
given these rains. However, the antecedent conditions are quite
dry, so the overall flash flooding threat should tend to be
isolated and confined to where any cell-training occurs.

Orrison

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

ATTN...WFO...FSD...GID...OAX...

ATTN...RFC...KRF...NWC...

LAT...LON   42519678 42329640 41989608 41059604 40219662
            40029759 40379782 40979744 41449734 41859727
            42349727