WORKING HYPOTHESES
- Numerical modelers can learn to incorporate more operational relevance
in their research efforts if they work closely with forecasters in an experimental
forecasting exercise.
- Operational forecasters can make more skillful interpretations of numerical
model output if they work with numerical modelers in an experimental forecasting
exercise.
SPECIFIC OBJECTIVES
- Overarching objective: To investigate emerging applications
for short-range ensemble forecasts (SREFs) and deterministic high resolution
predictions in the context of severe convection forecasting.
- Specific
research interests: (a) to compare the utility of experimental
high-resolution (convection-allowing) WRF-model forecasts with that of
operational mesoscale models in forecasts of convective initiation and
evolution, and (b) to explore the implementation and use of human-generated
perturbations in formulating a spectrum of initial conditions for mesoscale
ensemble forecasts.
- Specific operational interests: (a) to
explore the ability of SREF systems to provide unique and meaningful
guidance in operational severe weather forecasting, and (b) to examine
the utility of new high resolution models to predict convective initiation
and evolution, as it relates to improving lead-time for convective
watches.
RESULTS
- Numerous diagnostic algorithms were developed to provide a wide variety
of potentially useful analysis fields from SREF output
- Experimental forecasting exercises revealed that SREF guidance had
a measurable positive impact on predictive skill in experimental Day 2
convective outlook products.
- The use of human-generated perturbations showed promise in ensemble
forecasting; forecasts associated with this method of ensemble generation
outperformed the operational SREF in episodes with moderate-to-high probability
of severe weather occurrence, but not in cases of low probability.
- Convection-allowing numerical forecasts for the 0-12 h time frame were
found to be inferior to coarser-resolution operational forecasts, but
they were judged to be severely handicapped by a small integration domain
and very coarse initial conditions.
PAYOFF
- Many SREF diagnostic algorithms were tested, refined, and implemented
in SPC operations; they now play a major role in the preparation of convective
outlooks for the 1-3 day time frame.
RELATED PUBLICATIONS
Bright, D. R., S. J. Weiss, J. J. Levit, and D. J. Stensrud, 2003: The utility
of short-range ensemble forecasts in real-time prediction of severe convective
weather at the Storm Prediction Center. Preprints, 10th Conference on
Mesoscale Processes. Portland, OR, Amer. Meteor. Soc., CD-ROM, 2.8.
Bright, D. R. and P. Nutter, 2004: On the challenges of identifying the ''best''
ensemble member in operational forecasting. Preprints, 16th Conference
on Numerical Weather Prediction. Seattle, WA, Amer. Meteor. Soc., CD-ROM,
J11.3.
Bright, D. R., M. S. Wandishin, S. J. Weiss, J. J. Levit, J. S. Kain, and
D. J. Stensrud:Evaluation of short-range ensemble forecasts during the 2003
SPC/NSSL Spring Program. Preprints, 22nd Conf. on Severe Local Storms.
Hyannis, MA, Amer. Meteor. Soc., CD-ROM, P15.5.
Homar, V., D. J. Stensrud, J. J. Levit, and D. R. Bright, 2006: Value of Human-Generated
Perturbations in Short-Range Ensemble Forecasts of Severe Weather. Wea.
Forecasting, in press.
Kain, J. S., S. J. Weiss, D. R. Bright, M. E. Baldwin, M. Dahmer, and J. J.
Levit, 2004: Subjective verification of deterministic models during the 2003
SPC/NSSL Spring Program. Preprints, 20th Conference on Weather Analysis
and Forecasting/16th Conference on Numerical Weather Prediction, Seattle,
WA, Amer. Meteor. Soc., CD-ROM, 9.3.
2003 SPC/NSSL Spring
Experiment OPERATIONS
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SUMMARIES of previous SPC/NSSL Spring Experiments:
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Briefings newsletter
article about the 2003
SPC/NSSL Spring Program