A MOS equation for 12–24 hour PoP in the warm season might look something like:
PoP = 0.25 þ .0063(Mean RH) – .163(0-12 ppt [bin @ 0.1 in.]) – .165(Mean RH [bin @
70%])
where:
Mean RH (%) is the same variable as in Exercise 7.7 for the appropriate lead time 0-12 ppt is the model-forecast precipitation amount in the first 12 hours of the forecast [bin @ xxx] indicates use as a binary variable: =1 if the predictor is
xxx = 0 otherwise
Evaluate the MOS PoP forecasts for the following conditions:
12-hour mean RH 0-12 ppt
a. 90% 0.00 in.
b. 65% 0.15 in.
c. 75% 0.15 in.
d. 75% 0.09 in
Exercise 7.7
The fall (September, October, November) MOS equation for predicting maximum temperature (in
0F) at Binghamton, New York, formerly used with a now-discontinued dynamical model, at the 60-hour lead time was
MAX T = –363.2 + 1.541 (850 mb T) – .1332 (SFC-490 mb RH) – 10.3 (COS DOY) where:
(850 mb T) is the 48-hour dynamical forecast of temperature (K) at 850 mb
(SFC-490 mb RH) is the 48-hour forecast lower tropospheric RH in %
(COS DOY) is the cosine of the day of the year transformed to radians or degrees; that is, =cos (2pt/365) or = cos (3600t / 365) and t is the day number of the valid time (the day number for January 1 is 1, and for October 31 it is 304)
Calculate what the 60-hour MOS maximum temperature forecast would be for the following:
Valid time 48-hr 850 mb T fcst 48-hr mean RH fcst
a. September 4 278 K 30%
b. November 28 278 K 30%
c. November 28 258 K 30%
d. November 28 278 K 90%