20th Conference on Weather Analysis and Forecasting/16th Conference on Numerical Weather Prediction


The St. Patrick’s Day Snowstorm, 2002, Anchorage, Alaska

Joel C. Curtis, NOAA/NWSFO, Anchorage, AK; and J. M. Papineau, C. A. Scott, and K. Johnson

A quasi-stationary snow-band produced a record 29" of snow in less than 24 hours at Anchorage, Alaska March 17, 2002. What made this storm unique was the intensity and duration of the snowfall, as well as the limited spatial extent of the heavy snow amounts.

Even with the benefit of post-storm analysis it is difficult to fully understand the complex nature of this record event. Both the synoptic and mesoscale patterns were such that a forecaster would expect subsidence and drying over the Anchorage area. Synoptic scale NWP guidance gave no indication of snow-band development over Anchorage. High resolution mesoscale model output from both MM5 (15 km) and RAMS (4 km) failed to forecast either the location, or the amount of the snow. In fact consensus QPF from the models indicated that the heaviest amounts would occur across the southern slopes of the Kenai Peninsula, well to the south of Anchorage.

This paper will provide a detailed chronicle of events as they evolved as well as proposed mechanisms for the extraordinary local vertical motion field that produced the event. It is further hoped that broader exposure of the case will encourage dialogue between the Anchorage Forecast Office and the research community in order to better understand the mechanisms of this snow event.

extended abstract  Extended Abstract (868K)

wrf recording  Recorded presentation

Session 5, Case Studies (ROOM 605/606)
Monday, 12 January 2004, 1:30 PM-2:30 PM, Room 605/606

Next paper

Browse or search entire meeting

AMS Home Page