12.310
Assignment 7: Forecast Contest
Today’s assignment consists of the real
forecast contest! Each
of you will look at today’s weather and
forecast outputs and forecast the following three quantities:
Maximum Temperature
(Tmax)
Minimum Temperature
(Tmin)
Precipitation (Pcat)
for the Boston
area over the following day.
The following Forecast Contest Guide was designed to help you in collecting the information you need to do the
forecast. All information should be recorded in the
Forecast
Sheet and submitted by
7pm.
NOTE. This is what is expected from Assignment
7:
four forecast with completed Forecast Sheets
submitted
by 7pm on Tuesday, Wednesday, Thursday and Friday nights.
Forecast Contest Guide
Boston Weather
Use the PAOC
Synoptic Laboratory web to practice looking at the most
recent surface and upper air analysis maps.
Click on Boston Weather/Observations
and inspect the Last 24hrs surface obs to check on the
current weather in Boston.
Use
this information to fill the item - Boston
Weather - in the attached Forecast Sheet.
US Weather
Cick on Analysis/US and
examine the following maps:
GFS(Unisys)/Surface - identify
any significant features (low pressure area and fronts) close to the
Boston area.
GFS(Unisys)/500 mb – determine the strength of the upper level flow which advects the
surface system you have identified.
Next, look at satellite and radar data in Remote Obs to
observe the current position and movement of clouds and precipitation
over the U.S.
Use
these model analyses and remote sensing observations to fill in the item – US Weather -in
the Forecast Sheet.
Forecast Models
Graphical output
Click
on Forecasts/US and inspect
the forecast maps of the following two models:
ETA
:
Surface and 500
mb maps
and
GFS: Surface and 500
mb maps
Compare one model output against the other paying special attention
to the timing of events and the precipitation amount.
If the two regional model forecasts are quite different you can
also check the global model forecast maps: GFS.
Model Numerical Output
After inspecting the forecast maps to gain an overview of the forecast,
you can check the forecast values interpolated at the Boston location
by clicking on
Boston Weather/Forecast/Interactive Weather
Interactive Weather : fill in 'BOS' for the station
identifier and request '9: ETA Grid Interpolations' and 12: AVN Grid Interpolations' from the 'Model Data'
list.
Print these files or keep the windows open.
Use
this information to fill in the item - Model
numerical output - in the Forecast Sheet.
Model Statistical
Guidance
The National Weather Service (NWS) provides
statistical model guidance for all of its models. Years of past model forecasts and the observations of what
actually happened have been used to build up long-term statistics of
different weather events at specified locations such as Boston.
Interactive Weather:
fill
in 'BOS' for the station identifier and request '3: All Model Data'
from the 'Model Data' list. Check the statistical model
guidance: ETA MOS, GFS MOS, GFSX MOS
and NGM MOS (see attached A3
for explanation).
Use this information to fill in
the item - Model statistical guidance -
in the Forecast Sheet.
NWS Forecast
guidance
The NWS provides an 7-Day
forecast of temperature and precipitation probabilty at 12 hrs
intervals for all cities overt the US.
Use this information to record the
NWS
Forecast
guidance in
the Forecast Sheet.
3. Your forecast!!
Finally after collecting
all these information, you should have gained some appreciation of the
synoptic situation and of the consistency (or not) of the model
forecasts and you should be able to make your own forecast of
for the next day over the Boston area:
Maximum Temperature (Tmax)
Minimum Temperature (Tmin)
Precipitation (Pcat)
Precipitation categories (Note: If there is a trace of
precipitation, 0 and 1 both verify.)
0: no precipitation or a trace
1: trace to 0.05" of liquid, inclusive
2: 0.06 to 0.24", inclusive
3: 0.25 to 0.49", inclusive
4: 0.50 to 0.99", inclusive
5: 1.00" or greater
Scoring:
1 point for each degree of error on Tmax and Tmin.
4 points for each precipitation category error.
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