459
AGUS74 KWCO 251528
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT WED JUN 25 2025

.Synopsis...
Locally considerable flooding is possible today in portions of New
Mexico... Flash and river flooding possible through late week in the
Central Plains and Mid to Upper Mississippi Valley... Flash flooding
potential on Friday for Upstate New York and Vermont... Snowmelt runoff
continues to cause flooding concerns in portions of Alaska... Flash
flooding possible later this week across the Mariana Islands and American
Samoa...

.New Mexico...
Locally considerable flash flooding is possible across portions of NM
through day 2 (Thu), primarily near recently burned areas. Rainfall is
ongoing over the eastern and southern portions of the state, and additional
convective rainfall is expected later this afternoon. Cumulative rainfall
for the day is expected to be up to 2", with locally higher amounts
possible due to the convective nature of the rainfall. Low water crossings,
arroyos, and areas of steep or complex terrain will also be vulnerable to
flooding. The National Water Model (NWM) Short Range Forecast (SRF) is
signalling widespread exceedance of the 50% annual exceedance probability
(AEP) threshold across the upper Pecos and Canadian basins of eastern NM,
with isolated reaches exceeding the 10 - 4% threshold, supporting the
potential for flooding impacts outside of burn scar areas.

Rainfall coverage and intensity is expected to decrease after today, but
slow-moving storm cells will continue to pose a flash flood threat to
recently burned areas, including the Ruidoso area, through at least day 5
(Sun).

.Central Plains and Mid to Upper Mississippi Valley...
Multiple rounds of convective rainfall will bring the potential for flash
and river flooding to eastern NE, eastern SD, IA, northern MO, southern MN,
and WI through day 2 (Thu). A system is currently sweeping across the area,
having already brought 2 - 4", locally up to 7", to northern MO/southern
IA, and is expected to move over northern IA, SD, MN, and WI over the
course of the day (MRMS). Totals from this and subsequent rounds of
rainfall over the next 48 hours will be in the 2 - 4"+ range (WPC, HRRR).
The flood threat is higher across IA, southern MN, and WI than the
surrounding area, due to both higher QPF but also more vulnerable soils (50
- 75% RSM, 0 - 10 cm, NASA SPoRT) and elevated streamflows (USGS). Minor to
moderate river flooding is ongoing or forecast, especially in the Platte,
Grand, and Black basins where multiple locations are expected to reach
moderate flood status. Both the SRF and MRF versions of the NWM have robust
signals across this region. Most notably, AEPs from the SRF have been
especially strong (10 - 2%) on stream reaches in western WI and Central IA
over recent model runs, and these areas should be closely monitored for
out-of-bank rises on small streams. Urban areas such as Rochester, MN, La
Crosse, WI, and Des Moines, IA are also at risk of pluvial flooding should
heavier rates or storm training materialize.

.Upstate New York and Vermont...
Flash flooding is possible on day 3 (Fri) across far northern NY/VT due to
heavy rainfall. Rainfall totals of 2"+ are expected from this event, and
with topsoils near normal and streams running generally below normal, the
small stream and river flooding threat should be minimal. Flash flooding is
the primary concern due to the complex terrain of the area and potentially
high rainfall rates.

.Alaska...
Snowmelt continues to lead to high water levels and minor flooding on
various rivers across the state, and this will remain the case as long as
temperatures remain warm. The Chilkat River near Klukwan remains in minor
flood stage and is expected to remain above flood stage through today. High
water levels continue along the Yentna and Skwentna rivers in the Western
Alaska Range and the Matanuska River near Butte.

.American Samoa...
Heavy rainfall across the region may generate flash and urban flooding
impacts through day 3 (Fri). Landslides are also possible in areas of steep
terrain.

.Mariana Islands...
Heavy rainfall, (5 - 10") beginning as early as late on day 2 (Thu) and
continuing through day 5 (Sun), from monsoonal flow could produce flash
flooding across the islands.

//Bliss



$$