Lessons Learned HPC Surface Analysis Monday 12Z Forecast Concern Precip Type 850 mb Analysis Monday 12z Forecast Concern Precip Type 850 mb Analysis Tuesday 00z National Radar 1130Z National Radar 1830Z ID: 286552
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Slide1
Gabriel Lojero, Mike Thomas, and Nick Gliozzi,
Lessons LearnedSlide2
HPC Surface Analysis, Monday 12ZSlide3
Forecast Concern- Precip Type
850 mb Analysis, Monday 12zSlide4
Forecast Concern- Precip Type
850 mb Analysis, Tuesday 00zSlide5
National Radar 11:30ZSlide6
National Radar 18:30ZSlide7
National Radar 00:30ZSlide8
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) Slide9
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 50-60kt winds at 850 mb, the layer between the surface and 850 mb was stable, not conducive for mixing to the surface.Slide10
Verifying Snow Totals
Flurries: 18z 13
th – 12z 14th using NOHRSC interactive snow information and metarsSnow Shower and Light Snow 12z 13th – 12z 14th with same methodWere there moderate snow totals?Eliminated Snow Squall, Heavy Snow, Very Heavy Snow, and Blizzard based on snow totals and other criteriaSlide11
Verifying Snow Totals
12z 13
th – 12z 14thNOHRSC interactive snow informationSlide12
Flurries
All zones that received measurable snowfall and zones that traced snow after 18z using NOHRSC and
metarsSlide13
Snow Shower
Verified using NOHRSC 12z-12zSlide14
Light Snow
Verified using NOHRSC 12z-12zSlide15
Was there Moderate Snow?Slide16
Was there Moderate Snow? (Cont.)Slide17
SLEETSlide18
Where was there sleet?
Trained spotter reports sleet.
KLRF reported ice pellets. KPOF, just across border, reported ice pellets. Slide19
Confirming Sleet: Theory
KSRC
KARGKHKASlide20
Confirming Sleet: TheorySlide21
Where was there sleet?
Theory ConfirmedSlide22
Sleet Verification Slide23
FREEZING RAINSlide24
Where was there Freezing Rain?
Trained spotter reports FR.
KLIT reported FR. KPOF, just across border, reported FR. KRUE in zone 22 reported FR.
KMEM reported FRSlide25
Where was there Freezing Rain?
Theory ConfirmedSlide26
Freezing Rain Verification Slide27
Freeze/Frost
Verified using METARSSlide28
Verification Procedure
Searching for Precipitation >= 0.5 inchesSlide29
Verification Procedure
Precip >= 0.50 Inches Verification
Zones 23-24, 32-33, 44, 63-64, 68-69, and 73-75Slide30
T>40
F
3939393941414143
4040Slide31
T>40
F Verification Slide32
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.