The Pennsylvania State University-NCAR Mesoscale Model version 5 (MM5), run
ning on a triply nested grid, was used to simulate the intense lake-effect
snowstorm of 4-5 January 1995. On the finest grid (5-km resolution) centere
d over Lake Ontario, MM5 produced a snowband in the correct location having
a size and orientation similar to the band observed by the WSR-88D radar a
t Binghamton, New York. The simulated precipitation distribution agreed wel
l with the observed snowfall during the first 18 h during the time when the
snowband was in its midlake position extending into the Tug Hill plateau.
During the last 12 h of the simulation, when both the observed and simulate
d snowbands lay along the south shore of Lake Ontario, the simulated snowfa
ll at inland locations of Oswego County was less than observed. During this
period, the simulated precipitation over Lake Ontario appeared to be exces
sive, although no radar data or ground truth was available to confirm this.
Two short-wave troughs interacted with the Lake Ontario snowband. The tempo
rary weakening of the snowband after passage of the first trough was simula
ted well in the triply nested MM5 simulation. A comparison was made between
the operational Eta Model run and an MM5 simulation on a grid of comparabl
e resolution (80 km) in handling the passage of the second more vigorous sh
ort wave. Both the Eta and the 80-km MM5 were a few hours too early with th
e passage of this trough. The nested-grid version of MM5 was correct in sim
ulating the rapid southward movement of the band to Oswego County just afte
r the second trough moved east of the lake. However, because of the timing
error with the trough, MM5 was premature by a few hours in the southward sh
ift of the snowband.
Results on the 15-km grid indicated that moisture plumes from Lake Huron an
d Georgian Bay fed into the Lake Ontario band. In the lowest few hundred me
ters, these plumes were deflected around the Shelburne Plateau, which lies
between Lake Huron and Lake Ontario. Future research will focus on interact
ions between circulations downwind of Lake Huron and snowbands that form ov
er Lake Ontario.
The results of the 4-5 January 1995 simulation are sufficiently encouraging
to suggest that MMS may be used to make real-time forecasts of lake-effect
snowstorms. The lead author is participating in a COMET cooperative projec
t to provide lake-effect snow forecasts, in GEMPAK format, to the National
Weather Service Forecast Offices at Buffalo and Binghamton using a 20-km ne
sted grid over Lakes Huron, Erie, and Ontario. Despite relatively coarse re
solution, MM5 has produced useful predictions of snowband location and move
ment during the 1996/97 and 1997/98 lake-effect snow seasons.