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Going back to yesterday’s afternoon models (18z), both the RRFS and the NAM-NEST showed light radar shadows around 1 -3 AM; so light, I usually discount that level as model ‘noise’ especially from the NAM-NEST. The 18z NBM showed nothing.
I went off-duty 😉 after I posted here at 6 PM.
The next model runs (00z) (available after 8:30 -9:45 PM) of the RRFS showed no precipitation, except for a ‘short wave’ at 700 mb (10,000 feet) and high moisture content around 1 AM.
The 00z NAM-NEST and 00z HRRR DID forecast light snow in the 1 AM-4 AM time period, close to what we received.
So the take-away is the RRFS in its current form (the NOAA scientists have intentionally damped the convective precipitation in the current version because it was forecasting too high during development) is possibly now insensitive to light precipitation events. Something to keep in mind. NOAA is actively working on the next RRFS version which will have an entirely different ‘core’.
As for why the “Exclusive” forecast didn’t say a word about the snow… we’ll have to wait to hear if anything is mentioned.
Friday and Weekend Outlook
Posted Thursday 01/01/26 @ 5:42 PM — The models are in general agreement that the next few days will be dry and quiet weather-wise.
Earlier this week, it had appeared that several systems might affect us, but they now are forecast to move off to our south on Saturday and our north on Monday. The trend will be slowly moderating temperatures over the weekend with partly to mostly sunny skies.
By next Thursday and Friday, the AI models are forecasting highs 55º-60º. Wouldn’t that be nice! Unfortunately, it appears that rain will be in the picture on Friday.
Some additional insights. The TV weather people love to talk about weather “patterns” and often throw around that term when they really should just be saying there will be a “change in the weather”. With the ECMWF-AI forecast shown below for next Friday, there really is a sign of a true change in the large scale weather pattern.
The central part of the country has been incredibly mild, as a dip in the jet over the Northeastern US has left a ridge over the Midwest and South central regions. The forecast for end of next week suggests the dip in the jet will be in central US and we’ll be in the upstream warmer ridge and possibly wetter flow.
It will also open us up for Gulf moisture and the potential for coastal storms. To soon to know for sure, but expect changes beginning the end of next week.
Forecast Review
Happy New Year!
Here’s the radar image at 5:19AM—
2026 promises to be exciting from a weather data perspective. AI models continue to be advanced and developed . The RRFS and the REFS ensemble models are expected to become operational [early] this year. The NBM will be upgraded to version 5.0 sometime this Spring.
Several models will be retired in 2026 including the NAM, SREF, the NARRE, all three variants of the HIRESW along with the HREF models
Long-time visitors here know I’ve loved the NAM for snow forecasts, but the RRFS looks to be a much better model.
So here’s to 2026!
New Year’s Day
Posted Wednesday 12/31/25 @ 5:40 PM — One more quick update. The latest RRFS, just available, shows a fast moving squall line of light snow moving through about 6 AM Thursday morning. A bit more coverage of light snow than depicted earlier with the NBM. I guess we’ll see how good the RRFS is.
Posted Wednesday 12/31/25 @ 4:37 PM — Happy New Year! A quick update. The light flurries predicted for this evening, New Year’s Eve, are no longer forecast.
A strong cold front will move through before daybreak Thursday. The light snow Some light snow showers are expected with this front and the model blend (NBM) shows low probability of a coating of snow in a few areas northwest of the city—
The latest ECMWF shows a bit more coverage than the NBM, but still very light and scattered. For New Year’s Day, the models are predicting somewhat higher wind gusts, over 30 mph.
Temperatures drop after 6AM. Here’s the calculated wind chills based on the RRFS model for location: Center City Philadelphia.
Into the new year, dry through Tuesday with a warm up by Tuesday. Rain, not snow later Tuesday.
New Year’s Eve – Cold, Less Windy with Flurries
Posted Tuesday 12/30/25 @ 4:51 PM — It really felt cold today with the continued gusty winds that are finally expected to diminish somewhat on Wednesday and especially New Year’s Eve.
However, another reinforcing cold front is poised to move through here later New Year’s Eve, preceded by snow flurries and light snow showers. The NBM shows these flurries as accumulating a dusting to a coating Wednesday evening after 8 PM .
Additional flurries and snow showers into 8 AM Thursday morning.
As mentioned yesterday, New Year’s Day looks quite cold and windy with highs [maybe] just making it to 32º.
For the Mummer’s Parade, wind chills will be near 20º
Windy and Cold
Posted Monday 12/29/25 @ 9:56 PM — No big storms on the horizon. Windy and cold through New Year’s Day and beyond. A mixture of instability clouds and sunshine. The winds today have been impressive—
Speaking of New Year’s Eve/Day, a disturbance may bring some snow showers early New Year’s Day morning as a reinforcing cold front moves through. The Mummers Parade will have to deal with 30 mph winds and below freezing temperatures.
The next chance of snow (or another “mixed event”) appears to be Monday, according to the most recent ECMWF-AI model.
Previously Posted Sun @ 8:19 PM — —A warm front moves through tonight followed by a sharp cold front moving through between 11 AM and 1 PM. Some light rain is expected Monday morning with the warm front and ahead of the cold front.
Temperatures will be quite mild and peak about 11 AM, but with the cold front, temps will drop during the afternoon and will be below freezing by 7 PM.
It will also be increasingly windy in the morning and strong wind gusts will occur with the cold front passage into the afternoon, possibly to 40+ mph.
The word for the week will be “cold’. Cold high pressure will dominate through New Years Day. There’s a slight chance of snow flurries or a coating of snow New Year’s Eve. No major storms are forecast this week, but things may become more interesting over the weekend.