1. Lessons Learned
Gabriel Lojero, Mike Thomas, and Nick Gliozzi,

2. HPC Surface Analysis, Monday 12Z

3. Forecast Concern- Precip Type 850 mb Analysis, Monday 12z

4. Forecast Concern- Precip Type 850 mb Analysis, Tuesday 00z

5. National Radar 11:30Z

6. National Radar 18:30Z

7. National Radar 00:30Z

8. Verification Procedure
Eliminated all Zero Categories
- Easy: Dust (14), smoke (16), Wind Chill(18,19), Flood Categories (21-24), Big Snows (5,6,7,8), and Severe Weather(27), and IceStorm (11)
- Lightning (25) was ruled out based on PSU lightining data on ewall
- Visibilities from ASOS reports were > 0.5 mile (17)

9. Verification Procedure
The Search for High and Severe Winds
- used Mesonet and ASOS reports and none reported winds greater than 15 kts so Snow Squall (3), High Winds (12), and Severe Winds (13) were neglected.
- Even though there were kt winds at 850 mb, the layer between the surface and 850 mb was stable, not conducive for mixing to the surface.

10. Verifying Snow Totals
Flurries: 18z 13th – 12z 14th using NOHRSC interactive snow information and metars
Snow Shower and Light Snow 12z 13th – 12z 14th with same method
Were there moderate snow totals?
Eliminated Snow Squall, Heavy Snow, Very Heavy Snow, and Blizzard based on snow totals and other criteria

11. Verifying Snow Totals 12z 13th – 12z 14th
NOHRSC interactive snow information

12. Flurries
All zones that received measurable snowfall and zones that traced snow after 18z using NOHRSC and metars

13. Snow Shower
Verified using NOHRSC 12z-12z

14. Light Snow
Verified using NOHRSC 12z-12z

15. Was there Moderate Snow?

16. Was there Moderate Snow? (Cont.)

17. SLEET

18. Where was there sleet? Trained spotter reports sleet.
KPOF, just across border, reported ice pellets.
KLRF reported ice pellets.

19. Confirming Sleet: Theory
KSRC
KARG
KHKA

20. Confirming Sleet: Theory

21. Where was there sleet?
Theory Confirmed

22. Sleet Verification

23. FREEZING RAIN

24. Where was there Freezing Rain?
Trained spotter reports FR.
KPOF, just across border, reported FR.
KRUE in zone 22 reported FR.
KMEM reported FR
KLIT reported FR.

25. Where was there Freezing Rain?
Theory Confirmed

26. Freezing Rain Verification

27. Freeze/Frost
Verified using METARS

28. Verification Procedure
Searching for Precipitation >= 0.5 inches

29. Verification Procedure
Precip >= 0.50 Inches Verification
Zones 23-24, 32-33, 44, 63-64, 68-69, and 73-75

30. T>40 F 39 40 39 41 39 41 41 39 43 40

31. T>40 F Verification

32. Lessons Learned
Always look at a sounding to analyze stability parameter to determine if strong winds from aloft can mix down to the surface.
Always look at observations first to determine the most likely precipitation type during a future time period.
Verifying Precipitation amount: Mesonet and Cocorahs
ASOS stations do not have a brain (UP = Unknown Precipitation) . Our job to go through the data to determine what actually happened.
You can use soundings and visibilities to get a good idea of the type of precipitation.
GARP = Confusing interface...but great data.