Dylan Card Motivation Conclusion Methodology Results Introduction Unique terrain in eastern New York plays a pivotal role in weather in the Capital District Region In the absence of synoptic scale forcing convergence of surface winds channeled by topography can create difficult to predict s ID: 603306
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Case Study of a Topographically Forced Precipitation Event in the Capital District of New York, 2 January 2008
Dylan Card
Motivation
Conclusion
Methodology
Results
IntroductionSlide2
Unique terrain in eastern New York plays a pivotal role in weather in the Capital District Region.
In the absence of synoptic scale forcing convergence of surface winds channeled by topography can create difficult to predict snowfall and rain events.
Motivation
Conclusion
Methodology
Results
IntroductionSlide3
2 January 2008, A departing costal system off the New England Coast had dropped more than 15 cm of snow around the Capital Region
Unexpectedly an isolated band of snow created an isolated area of additional precipitation
Upwards of an additional 12.7 cm was reported in Cohoes, NY
Motivation
Conclusion
Methodology
Results
Introduction
1259 UTC
1328 UTC
1426 UTC
1357 UTC
1525 UTC
1456 UTCSlide4
Motivation
Conclusion
Methodology
Results
IntroductionSlide5
Motivation
Conclusion
Methodology
Results
IntroductionSlide6
Motivation
Conclusion
Methodology
Results
IntroductionSlide7
Motivation
Conclusion
Methodology
Results
Introduction
Model Data:
0.5 degree Climate Forecast Reanalysis System (CFSR), to produce a composite sounding for documented cold cases.
The times were chosen based on the closest time step to the maximum point of the event for the composite.
21km resolution Rapid Update Cycle (RUC) initialized at 12 UTC the 2 January 2008Slide8
Motivation
Conclusion
Methodology
Results
Introduction
Jet Forcing-300hPa
CVA- 500hPa
CAA- 850hPa
LSlide9
Motivation
Conclusion
Methodology
Results
Introduction
Jet Forcing-300hPa
CVA- 500hPa
CAA- 850hPa
L
Lack of upper level forcing!Slide10
Motivation
Conclusion
Methodology
Results
Introduction
Soundings for a) 2 January 2008 case and (b) cold MHC composite. Temperature (°C, red), dew point (°C, green), and winds (kt; full pennant, barb, and half barb denote wind speeds of 50, 10, and 5 kt, respectively).
a)
b)
a)Slide11
Motivation
Conclusion
Methodology
Results
Introduction
Moisture transport from bodies of water north of the region (Lake Champlain).
Convergence of
northwesterly winds (
westerly in the Mohawk Valley and northerly in the Hudson
Valley).
Low level warm air advection assisted in initiating the low level convection responsible for the unexpected snow event.
Only maintained during favorable northwest wind, as wind became more westerly the band fell apart and diminished. Slide12
Motivation
Conclusion
Methodology
Results
Introduction
Questions?