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FROM: John H. Ward
Chief, Production Management Branch
1. The resolution increase of the GFS from T254 to T382 has been
scheduled for Tuesday, 31 May. The highest resolution portion of the forecast
is
being extended from 84 to 180 hours. From 180 to 384 hours the model resolution
will increase to T190. The vertical resolution will remain at 64 levels to 180
hours and will increase from 42 to 64 levels beyond 180 hours. A couple of
minor
changes will be made to the pressure level GRIB files. These changes include:
A. Soil moisture and soil temperature -- Currently we provide soil moisture
and
temperature parameters that cover the depth of 10-200 cm below ground. We are
removing these parameters and replacing each of them with three new parameters
in
more discreet layers (10-40 cm, 40-100 cm, and 100-200 cm).
B. Potential Vorticity Unit (PVU) surfaces -- We currently make
available heights, temps, pressures, and winds on the +2 and -2 PVU surfaces.
We
are incorrectly labeling these levels in the GRIB PDS section from what is
defined
by the WMO. They are currently mislabeled as 0.002 PVU surface. We will
correct
this when the T382 is implemented. As a result of these changes, the size of
these
files is expected to increase by only 0.2 MB.
C. Convective cloud heights will no longer be available for the
analysis time period.
2. The OS upgrade of the Frost system is expected to be completed by 6 June. A
subset of forecast model output and all observational data is currently being
made
available on the Snow system. During the Snow upgrade, the model data will be
available on Frost. Once the upgrades are complete on both the Frost and Snow
systems, this subset of production data will be made available to the users of
both
of these systems.
3. In late June the resolution of the Rapid Update Cycle (RUC) will be
increased
from 20 to 13 km. There will be no change in format or content of forecast
model
output. At some point in the future, 13 km output will become available.
4. More details concerning all these model upgrades will be provided as they
become
available.
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