Currently: A cold front was over Central PA, with many waves of low pressure along it. This will be the focal pt of our wx today and tomorrow.
Tonight: Went slightly above guidance on temps. Temps prob rise to about midnight, then fall. The freezing line at dawn should be somewhere near or just N of the Merritt Pkwy. Lows generally 30-35. In this setup, the 35 vs 30 will be a big difference. Pcpn typ is all liquid, so those places where the temp is AOB freezing will begin to ice up.
Tomorrow: The NBM insists that just because it is daytime, temps must rise. However, when you have strong northerly flow and heavy pcpn falling in early Feb, that isn't the case. I went about 10 deg lower than NBM guidance, which allows for steady or slowly falling temps thru the day. Ptyp transitions to frz rain everywhere, then sleet from N to S. The entire state is under a winter wx advisory for icing. Pay attn to any products from NWS for possible upgrade to Ice Storm Warnings or changes to the advisories for portions of the state. If anything significant chgs during the aftn updts from NWS, I may do a quick updt. Please use extreme caution if you must travel tomorrow, since ice can be much worse than snow! Winds should not be overly significant, but there could be decent breezes. If enough ice accumulates on trees, w/gusts to 25-30 MPH, limbs can blow down and cause power probs.
Tomorrow Night/Sat: Icy tomorrow night. Pcpn is over by midnight, but it might be prudent to allow road crews several hrs to clean up afterwards. Breezy and cold Sun. Guidance reflects this pretty well, so followed pretty closely. Look for highs in the mid to upper 20s.
Long Term: Pretty quiet thru this pd. Sunday is sunny and cold. Temp guidance looks fine, w/advection near zero. Highs near 30 degrees.
Monday: Warmer, as high press shifts offshore. I did go a bit under guidance, just a deg or two, as I think the guidance may be overly aggressive w/warming us up as it won't be totally sunny. Highs generally in the upper 30s.
Tuesday: This is the only small concern of the pd. I inserted a 20-30 POP S coast only. A "coastal scraper" low has begun to show up on the models, and comes close enough to possibly graze the S coast with some light pcpn. GFS and GGEM models both agree on this. Any trends closer would bring a more sig pcpn event to the area, while any further would be just sunny wx. Right now, pcpn would be all snow and centered on the AM. Obviously a chg in storm track would result in chgs to the fcst. For highs, once again, I went just a bit below guidance, w/upper 30s for most, and maybe near 40 along I 91. These could be lowered if the storm does a closer approach.
Wednesday: We clear out behind any storm sys/front. Aloft we're cold, but it's sunny and the sfc flow is W/SW, so that limits how cold we can be. Guidance reflects this well, so followed closely. Look for highs in the low 40s.
Thursday: Air mass is cooler aloft, the same at the sfc, but for some reason the NBM is 2 deg warmer. Therefore, I went ahead and subtracted that 2 deg from guidance. Basically, the same wx expected as Wed, with highs in the low 40s and generally fair skies.
A cold front could approach Fri w/some snow and rain showers, and much cooler air behind it.
For our graphics today, here's a good one. Very simple: the entire state is purple on the NWS map, indicating a winter wx advisory.