Looking ahead, I'm not sure there is a whole lot to get excited about tbh. There is the tiny window centered around Jan 3 that is trending to a fropa with a quick zipping followup wave South of the region as cold chases precip. Could still be a burst of snow especially for the Southern parts of the region Monday AM.
Another longwave fropa centered near the 7th with a followup wave on its heels also. We'll see if there is a better look for that setup as lead times diminish.
Hemispheric pattern looks to be making adjustments starting in less than a week. Im wondering if the high lat blocking including the PAC monster near the Aleutians are shifting around due to this SSWE in the short term:
It is right after this that we can detect the PAC block propagating from Aleutian chain up into a negative EPO ridge, negative AO:
I've seen worse patterns modeled under 10 days, but more wanted to note the SWE ties to the HL ridging shifting around. The SPV is damn stubborn though and is not showing signs of being pushed around as much as we saw modeled a few days ago. The blob of warm convection in the strat at 132 hours should still be enough of a catalyst to try and shuffle things around wrt the HL tellies.
AO is forecast to move near neutral with a clustering weak negative:
Looking out farther, we also see the negative NAO ridge get shunted by the TPV as it tries and settle in near Baffin Bay. The NAO ens forecast reflects the TPV nudging the NAO out of the domain as it trends positive:
The former NAO ridge becomes more of a flat North Western Atl ridge. Meanwhile, the blocking in the EPO hangs on and there is a mid lat ridge extending all the way into the far n and w portion of the PNA domain. A weak split flow is trying to develop off the W Coast. Not the best positioned PNA (neutral to slight positive at best here) but I've seen worse looks.
The PNA is forecast to relax towards neutral. A better positioned ridge would likely have this index as a positive so we will see where this heads moving forward:
This ens prog hemispheric pattern reminds me alot of Feb 2018. Iirc, that wasn't the greatest month on record for winter weather. Here is the UL hemispheric pattern for that month which can be compared to some of the LR ens means looks:
What strikes me is based on the progression on the ens means developing that TPV near Baffin with other tellies comparable to early Feb 2018, once the pattern reloaded following the Baffin TPV which proved to be transient, the pattern rolled over on itself and went right back to a look similar to the current 500mb pattern with a big negative PNA, Aleutian PAC pig block, negative NAO, SER, (which the latter 2 linked up in 2018 similar to several times we have already see THIS winter). If you look at the temps for Philly in Feb 2018 you can see the roller coaster after the TPV moved out and the pattern rolled back to a big negative PNA with full lat ridging in the East:
Go back and compare the LR ens with the 2018 500mb early February means...striking similarities. Im wondering if we do end up with a period of warmth later in Jan (thaw?) after a period of cold/dry when the TPV meanders towards Baffin out towards the beginning of the 2nd week of January.
So I know first things first, but no way to sugarcoat the next 7 days or so seem rather uneventful for Philly proper in terms of winter weather. Many folks are begging for the pattern to reshuffle as we can't get much more boring actually. We should see things reshuffle towards the end of week one January. Signs are we finally get a cold air feed as the TPV positions itself near Baffin Bay and the EPO ridge allows for the cold in Western Canada to finally start to spill East and press South. Thereafter is a coin toss but there are similarities to Feb 2018 and if that former progression is to be believed, the pattern after the 'reshuffle' rolls over on itself and heads right back to a SER link-up with the N Atl ridge, a return to a negative PNA, and and stubborn PAC Aleutian ridge anchoring back in. This turned into quite a warm spell in mid Feb 2018 after a cold start and I am wondering if this is how Jan 2022 will also progress ie cold start followed by a significant Jan "thaw"?
