** N.A. Monsoon Experiment Options **
** DEFINITIONS **
[CPR] = Combined probability (Prob_Field_1 x Prob_Field_2 x ... x
Prob_Field_N)
[MAX] = Maximum from any member at each grid point
[MD] = Median
[MDXN] = Median value contoured. The dashed red line is the union of
all members at the lowest contour value plotted (i.e., where
at least one of the 16 members exceeds the value of the first
median contour). The dashed blue line is the intersection of
all members at the lowest contour value plotted (i.e., where
all 16 members exceed the value value of the first median
contour).
[MIN] = Minimum from any member at each grid point
[MN] = Mean
[MNSD] = Mean and Standard Deviation
[PM] = Probability Matched Mean Value
[PR] = Probability (percentage of members meeting/exceeding some
condition)
[SP] = Spaghetti
[TEXT] = Text product of the NAME zone averaged precipitation
** SPECIAL NORTH AMERICAN MONSOON EXPERIMENT (NAME) SHORT-RANGE
ENSEMBLE PRODUCTS FROM THE STORM PREDICTION CENTER **
A small sample of short-range ensemble products are provided for
evaluation during the NAME field program. The SPC calibrated
forecasts of the probability of a thunderstorm are downscaled to
a 4 km grid and recalibrated with lightning information on the
same 4 km grid. A similar technique is used to take the PQPFs
from the NCEP/SPC short-range ensemble and downscale/calibrate
the forecast to a 4 km grid.
These results are provided for scientific purposes commensurate with
the mission of the SPC and its appliation of short-range ensembles in
the prediction of severe weather. These products should be considered
highly developmental and non-operational.
** SPECIFIC INFORMATION ON AVAILABLE FIELDS **
[PR]Thunderstorm ->Probability of a thunderstorm for the 3-hr period
ending at the forecast time. The probabilities
are based on the SPC SREF calibrated thunderstorm
forecast on a 40 km grid, but recalibrated to a
4 km grid using surface elevation and recent
lightning observations.
[CPR]Organized Severe Thunderstorm ->The combined (or joint) probability
of a severe thunderstorm. The
predictors are the probability of
a thunderstorm (on the 4 km grid)
X probability DCAPE >= 500 J/kg X
probability MUCAPE >= 500 J/kg X
probability deep layer shear >= 20
kts. This is an uncalibrated
product and only meant to delineate
areas where CAPE, DCAPE, shear, and
thunderstorm potential are favorable
for organized thunderstorms
with potentially damaging winds.
[PR]24-hr Total Pcpn >= 0.01" ->Probability total precipiation exceeds
0.01" for the 24-hr period ending at
the forecast time. (Therefore, this
product is only available at F24 to
F63.)
[PR]24-hr Total Pcpn >= 0.25" ->As above but PQPF >= 0.25"
[PR]24-hr Total Pcpn >= 0.50" ->As above but PQPF >= 0.50"
[PR]24-hr Total Pcpn >= 1.00" ->As above but PQPF >= 1.00"
[PR]24-hr Total Pcpn >= 2.00" ->As above but PQPF >= 2.00"
[TEXT]24-hr Zone Ave QPFs ->NAME zone averaged QPF for the 24-hr
period ENDING at the forecast hour
selected (e.g., using the 09 UTC SREF,
the "F24" forecast represents the first
24 hours of the SREF forecast period
from 09 UTC to 09 UTC). The areal
averaged QPF is determined from the
downscaled PQPFs on the 4 km grid
in the Tier 1 NAME region. Average
values are calculated by summing
the probabilistic forecasts at the
various thresholds on the 4 km grid
within each of the nine zones, and then
dividing by the number of grid points
within the zone. The resulting areal
average thus represents the most likely
(zone averaged) QPF predicted by the
SREF.
Terrain Map ->Surface elevation of the SPC SREF NAME domain (meters)
All SREF information presented herein is for guidance purposes
only and should not be confused with official SPC operational
forecasts. Links to official SPC operational products are found
at the bottom of every menu.
Many of the SREF products were developed for testing the utility
of SREF analysis in the prediction of SPC mission critical items,
including: thunderstorms and severe thunderstorms, large scale
critical fire weather conditions, and mesoscale areas of hazardous
winter weather. In order to accomplish this goal and test new and
unqiue methods of SREF application in an operational environment,
many fields not produced in the NCEP postprocessor were calculated
locally for SPC purposes.
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