# Presentation: 859144

## Snowfall Analysis at FGFusing Snoopy and ArcGIS

- Mike Lukes
- NWS Service Hydrologist
- WFO Eastern North Dakota
- Grand Forks, ND

## Snowfall Reports to Graphic Analysis

-  Collect 1, 2, or 3-Day Snowfall Amounts from the Hydro DataBase (IHFS).
-  Transfer Snowfall Data from AWIPS to PC-based ArcGIS host.
-  Use ArcMap and Spatial Analyst to make  a raster Snowfall analysis graphic.

## SNOOPYAWIPS IHFS database “snooper”

- Developed by Mike Callahan, SH @ WFO Louisville, Ky. (Available from LAD).
- Graphical Interface to IHFS database.
- Interactively runs SQL queries, saves results in electronic files.
- Use INFORMIX flavor of SQL.
- Plan to use Mike’s Pref – preformater utility - in the near future.

## Slide 4

## SQL Queries

- 1, 2, 3, 4-day Snowfall Analysis
- 2-day Snow Depth Analysis
- Snow Water Analysis
- Other uses include AWOS 00z/12z precip amounts.

## 2-day Snowfall SQL Querry

- select * from snow s
- where s.obstime =
- (select max(obstime) from snow
- where lid = s.lid and s.pe=‘SF’
- and date(obstime) = today)
- and s.value>0
- order by 1 into tem tsf1;
- select * from snow s
- where s.obstime =
- (select max(obstime) from snow
- where lid = s.lid and s.pe=‘SF’
- and date(obstime) = today-1)
- and s.value>0
- order by 1 into tem tsf1;

- select lid, value, obstime from tsf1
- union
- select lid, value, obstime from tsf2
- order by 1 into temp tsft;
- select lid, count, (*) num,
- sum(value)  tot from tsft
- group by lid
- order by tot desc into tsff;
- select t.lid nwsli, round(t.tot,1) tot,
- round(l.lat,3) lat, round(l.lon,3)*-1 lon,
- t.Num num
- from tsff t, location l
- where t.lid=l.lid
- order by 2 desc;

## GNU gFTP client xfer Snow Analysis File to PC

- FGF uses the Linux gFTP utility to xfer the Snow Analysis SQL results file to samba mapped network drive
- Results file is accessible to ArcGIS on a local LAN PC.
- NWS CRH has a number of “floating licenses” for ArcGIS and Spatial Analyst which the region’s WFOs can use locally.
- Pref may be able to bypass gFTP step.

## Slide 8

## Snow Amounts in ArcGIS plotted on FGF HSA County Background

- Results file contains NWSLI, Snowfall Amount, Lat, Lon, and # of daily obs.
- Snow Amounts are plotted (add XY data from tools menu) on HSA county background.
- NWSLIs can be also plotted for geographical orientation.

## Slide 10

## Spatial AnalystSnow Analysis

- Interpolated to Raster using:
- Inverse Distance Weighting
- Spline...???
- Kriging...???
- ArcUser Magazine Jul-Sep 04 “Interpolating Surfaces in ArcGIS Spatial Analyst”
- To do: Compare spline and kriging to IDW for a better analysis.

## Contouring and Time Stamping

- Spatial Analyst – Surface Analysis – Contour function.
- Specify contour intervals.
- Day/Time Stamp VB add-on.
- DateElement icon put on toolbar.
- Available from ESRI web page.

## Improvementsnotes, ideas and limitations

- Use Pref for SQL query and file xfer
- (RRM?)
- Snow Obs from buffer counties
- Improve boundary conditions for better analysis near borders
- Can serve as 1st guess for subjective analysis
- Compare to sat pix
- IDW not good fit to natural snowfall patterns
- Kriging?
- Easier process to send to graphic to web

## Slide 14