Synopsis…
All eyes are already shifting to the large storm expected to move into the region for Sunday, but until then, we'll have to deal with continued cold and snow showers. After what may be the coldest night of the season so far, a weak clipper system will drop down from the Great Lakes and bring scattered snow showers to the area. In the wake of this system, the flow turns more southerly ahead of a strengthening low that may strengthen rapidly as it reaches the coast. There is still very little agreement in guidance for this system, but some type of frozen precip will reach PA at some point by Monday morning. We can definitely say the coldest air of the season will settle in for the early part of the week.
Short Term…
Lake effect snow is slowly giving way to high pressure located to our NE, which will hang around just long enough to keep conditions right for a cold night; MOS is in the teens for the CTP area. The weak clipper is running into lots of dry air, GFS-MOS-indicated dew points in the single digits. Right now we think any measureable snow will be north of I-80. Models agree on general southerly flow, pumping milder air upward for Saturday…temps reaching into the 30s for many areas for the first time in a while.
Long Term…
Models are confuzzled on the weekend…run-to-run and model-to-model inconsistencies abound. 0z GFS runs looked a little more promising for snow, but new 18z runs show a more westerly track…Even more interesting, any discernable trends suggest it's more likely the western low will not even merge with weak coastal low until after they pass PA; this would result in a busted storm for us, with light precip. Going with an ensemble mean, it looks like the rain-snow line is trying to set up right thru the CTP CWA. In depth looks show a mix for UNV, all snow for DUJ, and all rain for PHL. It seems like no one has been able to pin this storm down yet, so we're generally going with means…Our consensus says things are far too uncertainty for anything else. Expect some accumulating snow in the NW and maybe PIT, and periods of mdt to hvy rain in the SE, but in between a mix is most likely, transitioning to rain, especially with indications of upper-level warmth sneaking into some forecasted profiles…meaning FZRA may be a problem. But 18z WRF keeps storms apart, giving UNV region light rain with some light snow on the backside. Still, HPC has >40% chc of 4+" of snow in western PA. Timing of storm is at least looking more certain, with precip moving in Sun night and lasting into Mon. Lake effect looks likely again afterward, with Arctic air moving in. High temps may struggle to top 10 F in BFD Tues...May need to closely monitor potential for dangerous wind chills during PSU finals week.
Forecaster: Matt Mahalik
No comments:
Post a Comment