The National Weather Service in Pittsburgh started Christmas Day with a forecast that was less about snowfall landscapes and more an expectation of a cloudy, cool yuletide free from precipitation; folks can expect dry conditions today along with a gradual temperature increase through the week, heading into a warmer weekend where rain will come visiting, National Weather Service.
This morning's fog, with visibility down to a mile in some spots, should lift post-sunrise, giving way to the predominant cloud coverage that's set to hover over the day. However, the upper-level height rises this morning that will be stunted this afternoon by a weak shortwave trough, blunting the potential for any significant solar warm-up. Thus, Pittsburgh’s Christmas will clock near seasonal averages in the temperature department.
Looking ahead, the NWS indicates that the enforced ridge is expected to amplify Thursday, which invites a continued dry spell but introduces better surface warm advection, warming temperatures that will push thermals even higher by Friday, setting the stage for weekend highs that could climb well above the average for this time; confidence is high enough that Pittsburgh and areas to the south should expect temperatures in the 50s with even some 60s not out of the question.
Saturday ushers in a wetter agenda. Forecasters are seeing a consensus on the return of rain, but differences in timing are giving them pause. A speedy trough could mean a soggy start to the day, while a dalliance would delay the downpours until later. Sunday is more likely to bear the brunt of the rainfall, which extends into the early days of next week. However, the outer reaches of that forecast remain hazy and have very low confidence due to the diversity seen in ensemble models.
Airmen might also find the forecast challenging. Pockets of LIFR fog and variable clouds have made for a low-confidence near-term outlook, though improvement to MVFR is expected around midday; the weak ridge lingering overhead suggests slow alterations in flying conditions, with a non-zero possibility for light precipitation this afternoon, and VFR conditions likely returning by evening except for specific terminals that could experience prolonged MVFR into Thursday.
According to the latest briefing from the NWS Pittsburgh office, no current weather advisories exist for Pennsylvania, Ohio, or West Virginia. Thus, the region will have a quiet, possibly reflective Christmas Day followed by a gentle lead into the new year. Like time itself, nature seems intent on a dyad of calm and turbulence.
