Technical Discussion

Synopsis...

High pressure will slide through the region today and tomorrow before a strong cold front sweeps through on Thursday bringing the first flakes of the season to NC and NW zones.  High pressure will again build in for the weekend, allowing temps to rebound above normal by Saturday under sunny skies.

Short Term (Tues-Wed Night)...

Stubborn inversion keeping clouds in place across majority of Commonwealth this morning.  Dense fog reported in some spots (<1/4 SM at KUNV) but should continue to burn off throughout the morning.  Temperatures should rebound to seasonable levels this afternoon as sun peeks through across most of the state.  A cool night for much of the state tonight as skies clear due to a region of high pressure.  Some cool spots could drop below freezing but not expecting a widespread freeze.  Tomorrow looks like a nice day as we are under the center of the high pressure system.  Skies should be partly cloudy and allow temperatures to climb to normal values by afternoon.  A few more clouds begin moving into western zones after dark tomorrow as next weather maker approaches from the west.  Some showers are possible late across western zones but do not expect anything heavy.

Long Term (Thurs-Sat)...

Hardest part about the forecast was timing of frontal passage on Thurs and possible snow showers for NC and NW zones Thurs/Thurs night.  Current timing of FROPA is after midnight on Wed night across western zones and by mid morning across the east.  WRF is much stronger with parent low pressure system (990mb) as it moves thru Canada, in contrast with 994mb with the GFS.  Went with the stronger WRF for now, mainly because the trend seems to be toward a sharper trough at 500mb.  In any event, scattered showers are the story for the state on Thursday due to northwesterly flow/orographic lift/lake effect.  Expect blustery conditions Thurs/Thurs night/Fri as low deepens to our NE.  As for snow, we mentioned the wording in NW and NC zones as 540dm and 0c line are well south.  Accumulations should be hard to come by due to warm sfc temps as well as light nature of precip.  However, if a heavier band does form, grassy areas could be covered.  Should monitor the snow potential for northern zones, especially if low temps on Thursday night become an issue (below freezing...hazardous driving conditions?).  Friday will be much nicer but still breezy.  High pressure slides to our east of Saturday, allowing the return flow to bring us warmer temperatures and a beautiful weekend.

-Dan DePodwin