upslope

August 28, 2026 New England rain event — forecast vs. what fell

event hit rate 55% MAE 0.09″ 31 mountains scored

On August 28, 2026, 9 of 31 scored New England ski resorts recorded measurable rain, peaking at 0.36″ near Black Mountain. upslope’s day-before forecasts verified at a 55% event hit rate with a mean absolute error of 0.09″ across 31 mountains. Ground truth: median of CoCoRaHS volunteer gauges near each resort (min 2 reporting).

Mountain by mountain

Resort	Forecast	Measured	Error	Call
Black MountainNH	0.07″	0.36″	-0.29″	✗
SaddlebackME	0.03″	0.32″	-0.29″	✗
SugarloafME	0.06″	0.32″	-0.26″	✗
OkemoVT	0.19″	0.15″	+0.04″	✓
BromleyVT	0.22″	0.13″	+0.09″	✓
AttitashNH	0.05″	0.12″	-0.07″	✗
CranmoreNH	0.04″	0.12″	-0.08″	✗
KillingtonVT	0.09″	0.12″	-0.03″	✗
Mount SnowVT	0.08″	0.11″	-0.03″	✗
PicoVT	0.1″	0.09″	+0.01″	✗
Magic MountainVT	0.07″	0.07″	0.0″	✓
StrattonVT	0.08″	0.07″	+0.01″	✓
Berkshire EastMA	0.14″	0.03″	+0.11″	✗
Bretton WoodsNH	0.06″	0.03″	+0.03″	✓
Mad River GlenVT	0.06″	0.03″	+0.03″	✓
SugarbushVT	0.05″	0.03″	+0.02″	✓
WildcatNH	0.11″	0.03″	+0.08″	✗
BurkeVT	0.06″	0.01″	+0.05″	✓
CannonNH	0.19″	0.01″	+0.18″	✗
Jay PeakVT	0.04″	0.01″	+0.03″	✓
LoonNH	0.21″	0.01″	+0.2″	✗
Bolton ValleyVT	0.03″	—	+0.03″	✓
CrotchedNH	0.04″	—	+0.04″	✓
GunstockNH	0.02″	—	+0.02″	✓
Mount SunapeeNH	0.05″	—	+0.05″	✓
Pats PeakNH	0.04″	—	+0.04″	✓
RaggedNH	0.06″	—	+0.06″	✓
Smugglers' NotchVT	0.02″	—	+0.02″	✓
StoweVT	0.03″	—	+0.03″	✓
WachusettMA	0.3″	—	+0.3″	✗
Waterville ValleyNH	0.24″	—	+0.24″	✗

Forecast = upslope's last published NWS-based rain number the day before. ✓ = correctly called rain above/below 0.1″. Positive error = over-forecast.