AGUS74 KWCO 121839
AHDNWC

Area Hydrological Discussion #080 - EXPERIMENTAL
NWS National Water Center - Tuscaloosa, AL
133 PM CDT Fri Apr 12 2024

WHAT: Small stream and river flooding
WHERE: Eastern New York into western Maine
WHEN: Through late this evening

FORECAST RAINFALL AND ANTECEDENT CONDITIONS...
QPF: up to 2" (HRRR)
QPE: 0.5 - 1.5", locally higher (6 hr, MRMS QPE)
Rates: up to 0.75"/hr (HRRR)
Soils: 70 - 100% saturation (0 - 40 cm, NWM Soil Moisture Analysis)
Streamflows: Much above normal (USGS)
Snowmelt: Up to 4 (SNODAS)

DISCUSSION...
Persistent moderate rainfall today has resulted in soils becoming
saturated and snow packs becoming ripe for abundant snowmelt over the
region. Additionally, temperatures and dew points are seasonably
high, supporting increasing concerns for rapid snowmelt over the
region. Though rainfall will be rather light (up to 0.75"/hr), the
combination of snowmelt, rainfall, and already saturated soils will
support rapid runoff, increasing the potential for flooding impacts.

The latest guidance from the HRRR-forced NWM is indicating scattered
small stream responses over eastern NY into western ME, with
probabilities (50 - 100%) of rapid onset flooding across much of the
area of concern. Corresponding annual exceedance probabilities, from
the High Flow Magnitude Magnitude forecast, of 10% or less (as low as
2%) are noted along small streams draining the White(NH) and western
ME mountains, indicating that locally significant small stream rises
are possible.

GRAPHICAL REPRESENTATION weather.gov/owp/operations-ahd

Additional National Water Center products are available at
weather.gov/owp/operations

//GKendrick

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