Radar Based Case Study of a Northeast Colorado Winter Storm

Radar and conventional meteorological data collected during the 19-20 January 1991 winter storm over Northeast Colorado as part of WISP-91 (Winter Icing and Storm Project) were analyzed to describe observations of snow bands and possible band formation mechanisms. A review of the synoptic situation...

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Bibliographic Details
Main Author: Powell, Nicolas S.
Other Authors: AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
Format: Text
Language:English
Published: 1992
Subjects:
Meteorology
*METEOROLOGICAL DATA
*RADAR METEOROLOGY
*STORMS
KINEMATICS
VELOCITY
CLOUDS
AIR
OBSERVATION
STRUCTURES
PROFILES
WINTER
COLD FRONTS
ANTICYCLONES
GRAVITY WAVES
COLORADO
INSTABILITY
AZIMUTH
CLASSIFICATION
BARRIERS
SNOW
MOUNTAINS
DOPPLER RADAR
WIND
THESES
TERRAIN
ICE FORMATION
*WINTER STORMS
SEEDER FEEDER CLOUDS
COLD AIR DAMMING
JET STREAK CIRCULATIONS
SNOW BANDS
UPSLOPE STORMS
WISP-91(WINTER ICING AND STORM PROJECT)
BARRIER JETS
Arctic
Online Access:http://www.dtic.mil/docs/citations/ADA258256
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA258256
Description
Summary:Radar and conventional meteorological data collected during the 19-20 January 1991 winter storm over Northeast Colorado as part of WISP-91 (Winter Icing and Storm Project) were analyzed to describe observations of snow bands and possible band formation mechanisms. A review of the synoptic situation led to classification of this storm as an anticyclonic type of upslope storm. Single and dual-Doppler radar analyses showed well organized mesoscale snow bands oriented west-southwest to east-northeast, parallel to the 800-400 mb thermal wind, formed during upslope conditions several hours after passage of an arctic cold front over the research area. Embedded within the bands were precipitation cores that propagated along the band with the upper level winds and nearly stationary (band relative) trapped mountain waves. The evolution and structure of snowband kinematic properties were studied by analysis of horizontal and vertical velocity profiles and reflectivity distributions using PPI scans and Extended Velocity Azimuth Display (EVAD) techniques. Various mechanisms were examined for their potential role in formation and maintenance of snow bands. These mechanisms included: conditional instability, Conditional Symmetric Instability (CSI), ducted and internal gravity waves, jet streak circulations, seeder-feeder cloud structures, and terrain induced phenomena such as trapped mountain waves, low level barrier jets, and cold air damming.

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