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Strategies to Improve Radiation Fog Forecasting at Elmira, NY (KELM) . Robert Mundschenk, Michael Evans, Michael L. Jurewicz, Sr., and Ron Murphy – WFO Binghamton, NY Aviation Sub-Regional Workshop September 16, 2008. Outline. Motivation Methodology Study Results A New Forecaster Tool
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Strategies to Improve Radiation Fog Forecasting at Elmira, NY (KELM) Robert Mundschenk, Michael Evans, Michael L. Jurewicz, Sr., and Ron Murphy – WFO Binghamton, NY Aviation Sub-Regional Workshop September 16, 2008
Outline • Motivation • Methodology • Study Results • A New Forecaster Tool • Summary
Motivation for Research • KELM experiences radiation fog frequently with resultant IFR / LIFR / VLIFR conditions • Historically, this has been a challenging site for aviation forecasters • Unexpected dense fog development • Overly pessimistic forecasts (lighter fog than expected)
Favorable Location for Fog KELM Chemung River Valley
Methodology • Fog Season - April 1st through November 1st • Compile a list of dates with clear skies and light winds • 3 Full Seasons worth of data (2001-2003) • Minimum observed visibilities and time durations of IFR conditions were tabulated • Many parameters thought to be pertinent to fog formation were tabulated • NAM Boundary layer wind, lapse rate and RH forecasts • Observed minimum temperatures • Observed Cross-over temperature • Observed Chemung River temperatures • Amount of recent rainfall, if any • Time of year (month)
Results • Most reliable indicators of low visibilities (dense fog): • Light wind speeds (< 13 kts) around 950 mb (700 feet AGL) from NAM BUFKIT soundings • Overnight low temperature colder than the cross-over temperature • Large differences between the observed Chemung River temperatures and the minimum air temperature (air temperature at least 20 degree F colder than the river temperature). • Heavy rain during the period 4 to 10 days prior to the event in question • Model low-level RH and lapse rate correlated weakly with fog occurrence
A New Forecaster Tool • Based on study results, a “pattern recognition” tool was developed • Data inputs from BUFKIT soundings, observed data and forecaster input • Help forecasters better differentiate between favorable and unfavorable nights for fog formation • Provides links to past events that most closely match the set of expected conditions
Final Thoughts • This tool allows forecasters to use pattern recognition to forecast fog • The tool promotes a probabilistic approach to fog forecasting • Similar tools can be developed for other TAF sites • Verification will be done next summer • We still need to know more about what parameters can help us to forecast fog