Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
313 AM EDT Wed May 27 2026
Day 2
Valid 12Z Thu May 28 2026 - 12Z Fri May 29 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE CENTRAL AND SOUTHERN PLAINS, NORTHERN ROCKIES, LOWER
MISSISSIPPI VALLEY, AND SOUTHEAST FLORIDA...

...Plains to Lower Mississippi Valley...

A bit of an omega block pattern is shaping up across the CONUS with
a broad upper trough axis fixated over the Central and Southern
Plains with with ridging in place over the top. This will cause a
rather chaotic flow under the mean trough with deep moisture and
several smaller mid-level perturbations basically "stuck" under the
the overall trough axis. Ample instability with deep moisture
presence will certain be a cause for continuing at least a
scattered heavy rain footprint across areas under the influence of
the trough. Scattered elevated probabilities between 30-60% exists
for localized amounts >2" from KS all the way into the Southeast
U.S. with the maxima split between KS and the Central Gulf coast.
The two areas are different in the reasoning as the primary center
of the trough will be fixed over KS leading to the best upper
forcing pattern and stagnant flow remaining parked over the area as
we move through D2. Pending the amount of rain that falls over the
course of D1, a targeted upgrade is possible, but maintained the
MRGL and will reassess as we move forward in future updates to see
if an upgrade is warranted. The Central Gulf coast will remain in a
favorable instability maxima with weak flow likely a component that
could lead to isolated heavy totals stemming from slow-moving
convection. The area from the Upper TX coast over through southern
GA has been leaning wet over the past week, so antecedent
conditions are a little more unforgiving for these types of setups.
In any case, the threat remains modest, at best, so the MRGL risk
was sufficient for the pattern with any upgrades likely to stem
from more near term sampling of the radar trends.

...Florida...

Active sea breeze pattern with weakening steering flow will lead
to a period of heavy rainfall across the southeast FL coast on
Thursday afternoon. Consensus within guidance is for an active
period between 18-00z Thu/Fri that would allow for heavy convection
with slow forward propagations to impact the South Florida metro
corridor from West Palm Beach down to Miami. Latest 00z HREF is
modestly robust with the signature for at least 3" off the
neighborhood probabilities with a steady 60-90% output along the
southeastern coast of FL with the maxima generally confined to the
Miami Metro up to West Palm Beach. This correlates strongly with
what has been advertised via regional and global guidance the past
few days with the deterministic CAMs even indicating some 4-6"
bullseye's within the main QPF footprint. This is a relatively
classic pattern capable of locally significant rainfall within a
deep moisture presence as PWAT anomalies sit between +1 to +2
standard deviations within the various ensemble packages. A MRGL
risk remains in effect for the period across the South Florida
metro corridor.

...Northern Rockies...

Maturing ULL over the west coast will allow for a broad axis of
diffluent flow across the interior northwest with the highlight of
scattered convection likely to pivot further west into eastern WA,
northern ID, and the western slopes of the Northern Rockies.
Signals are not as prevalent compared to previous periods, however
the environmental conditions are still favorable, especially when
it comes to PWAT anomalies still generally running between the
90-95th percentile across northeast WA into northern ID. Burn scar
remnants will likely be the most susceptible to seeing impacts, so
the threat remains low-end and generally localized. Maintained
continuity from the previous forecast with a MRGL risk in place
across the aforementioned areas.

Kleebauer


Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt