This snowstorm was an exceptional forecast challenge,
as the precipitation transition zone was difficult to forecast. Forecast guidance depicted a relatively narrow
precipitation transition zone just north and west of the Capital District until
12 hours prior to the onset of precipitation when one set of forecast guidance
shifted the precipitation transitions zone just south and east of the Capital
District. It was not known if this one
set of guidance was accurate or not, so it was difficult to determine whether a
major change in the forecast was needed in the near term. The subtle shift in guidance was so subtle
that it was difficult to determine of the shift was enough to warrant major
changes to the forecast precipitation type forecasts across the Capital
District. The clearest indicator of
major changes to expected precipitation types across the Capital District was
in the plume diagram from the GEFS initialized at 00Z 25 February, which
changed from a mix to all snow, which was different than the SREF which kept
indicating a mix. However, this was only
one set of guidance, and not enough of a consensus, compared to the SREF and
of MSLP from (left to right) the GEFS, GFS, SREF and
of 850 hPa winds from (left to right) the GEFS, GFS,
of 850 hPa temperatures from (left to right) the
GEFS, GFS, SREF and
Above: Loops of 925 hPa temperatures from the GEFS and GFS. Note the very tight thermal gradients and slight shift eastward of the 0C line in the later guidance.
Above: Loops of probabilities for 1 inch in 12 hours from the GEFS and SREF.
Above: Loop of surface maps showing the track of the surface low.
Successive soundings from
Above: Loops of observed 300 hPa, 500 hPa, 700 hPa and 850 hPa heights, temperatures and winds.
Above: Radar loop of reflectivity through the event.