1. Penn State Weather Camps
Basic Weather Forecasting Guidelines
Sat I - NWS - Radar - Radar
sfc. map 1 - sfc. map 2 – sfc map 3

2. Basic Forecast Guidelines
Deterministic Forecast
precise/exact/no uncertainty provided
Non-Deterministic Forecast
uncertainty provided via a range or probability
High: 82
Cloud: 8
Rain: Yes
Deterministic or Non?

3. Basic Forecast Guidelines
Weather Models … What are they?
Name some ….
NAM
GFS
ECMWF
CMC

4. Basic Forecast Guidelines
Weather Models … What’s under the hood?
NAM
GFS
ECMWF
CMC
Mathematical Equations …. “Perfectly express the physical processes
of the atmosphere”

5. Basic Forecast Guidelines
Weather Models … What do we “feed” them?
Run 2 times a day (12z/00z)
NAM
GFS
ECMWF
CMC

6. 10 7 6 9 5 8 11 3 2 1 4

7. Basic Forecast Guidelines
Weather Models … What do we “feed” them?
(THE INPUT = real observations)
Run 2 times a day (12z/00z)
NAM
GFS
ECMWF
CMC
Output = Forecast

8. Basic Forecast Guidelines
What causes rain?
Need clouds!
Will any ole cloud do?
Moisture supply
Bodies of water – Moisture content of air
Upward motion:
How does this affect clouds/precip.?
Mechanisms for “lift”
Fronts – Topography – Low Pressure – Jet stream dist.
(In) stability:
Warm down low … cold up high!