Highlight: Colder midday model run. Boston 5/0 on Jan. 21.
Midday 12Z GFS…
Days 6-10: Colder Northeast.
Days 11-15: Colder East.
|Dates||HDD forecast||12-hr change||24 hours ago||NOAA Nml|
Table 1: CWG tabulates the 12Z GFS OP gas population weight HDD forecast into later January.
The fine print…We’re expecting a colder East climate to evolve the last 1/3 of January. However, in today’s climate signal forecast in the extended-range the NAO becomes weak positive in 12-16 days while the MJO may regenerate in phase_5 (Indonesia) which supports a warm U.S. climate. The midday cold model run is too cold!
Weekend snowstorm…Forecast amount increases Ohio Valley with widespread 5-10 in. and locally higher amount south-central Illinois (Fig. 1). However, the storm is not quite as intense as previously forecast across the Mid-Atlantic States and the Virginia forecast amount is cut back to the 4-8 in. range. This is the just-received 12Z GFS OP forecast.
Fig. 1: The 12Z GFS OP depiction of a SAT/SUN snowstorm stretching from the Ohio Valley to the Mid-Atlantic region.
Midday model/Boston MAX/MIN forecast…A vigorous cold 12Z GFS OP model run indicates a max/min forecast of 5/0 in Boston Jan. 21.
Fig. 2: The 12Z GFS OP depiction of the 15-day MAX/MIN forecast for Boston, MA showing arctic air for Jan. 20-22.