textproduct: State College

WHAT HAS CHANGED

* Bumped PoPs up to categorical (80-100pct) for most of the CWA on Friday afternoon. * Confidence rising in timing of frontal passage and related precip on Sunday and Sunday night along with refinement of QPF.

KEY MESSAGES

1) Temperatures start a steady climb today with a couple of showers today and a widespread light to moderate rain on Friday.

2) Cold frontal passage Sunday should make widespread rain showers perhaps ending as a brief period of snow across the north.

DISCUSSION

KEY MESSAGE 1: Temperatures start a steady climb today with a couple of showers today and a widespread light to moderate rain on Friday.

Despite a cloudy day, the warm advection and warmer start to the day vs Wed, we should add 8-10F to maxes today vs Wed. The warm front pushing across early this morning will be followed very shortly by a very weak/moisture-starved shortwave trough with the slightest of a surface reflection. As the trough at the sfc passes this aftn, we will see one or two SHRA develop to our west and push into the Alleghenies. Most models make a few dots of QPF <0.02". Higher chc (30%) of getting wet will go to the Laurels.

Next wave is a Clipper system with a sfc low that crosses LM and LE, then thru the Finger Lakes. There is more moisture carried along by the system and it may actually tap a little Gulf moisture as it reaches our longitude. Consensus QPF is around 0.50" in the nrn tier and <0.25" in the Lower Susq and south-central mountains. The SHRA should arrive in BFD around or just before noon (when temps will be 35-40F), and 4 PM in JST-UNV-IPT. They should continue southward and be off into MD around 10-11 PM. A rumble of thunder is not out of the question over the west as they pass thru. Maxes will end up another 10F milder than the previous day (49-63F across the CWA fm N to S).

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KEY MESSAGE 2: Cold frontal passage Sunday should make widespread rain showers perhaps ending as a brief period of snow across the north.

990mb sfc low over ND Sat evening will ride quickly to the east. The sfc low is progged by most models to be somewhere near BUF Sun evening. The warm advection precip looks like it will pass mainly north of PA for Sunday daytime. A little -RA may brush the far nrn tier during the daylight hours. More certainty exists in the passage of the connected cold front on Sunday night.

QPF Sun night actually looks very similar to Friday's amounts. Much of the precip will fall along and behind the front. The cold air being forced in from the N and the rainfall will quickly drop temps Sun night. Despite maxes in the upper 50s in the N (they'll be near 70 for the srn half of the CWA) on Sunday, the cooling will probably (50%) turn the rain to SN over the nrn mtns. If it does turn to SN there, it shouldn't over the central and srn two- thirds of the CWA due to the warmer start when the rain arrives. Maybe a little mix could happen on the top of the ridges of the central mtns. Mins will be 25-30F in the N, but just above 40F along the MD border (lower elevs). The precip will be S of the MD border around or just after sunrise Mon.

Mon-Tue look dry with temps a little below normal. Wed should be a few degs warmer than normal and Thu much warmer with lots of places >=60F.

AVIATION /06Z THURSDAY THROUGH MONDAY/

Overcast skies tonight with light winds will be the story for the beginning of this TAF package. Overall ceilings should remain VFR with broken to overcast clouds between 5,000 and 10,000 ft. The usual spots of lower cloud heights are being observed at BFD and JST. These two sites will largely remain MVFR through today and into tonight. Occasional isolated snowshowers off Lake Erie could cause additional restrictions at BFD, but confidence in these impacts remains less than 50%.

Clouds will remain overcast throughout the day today thanks to a weak passing warm front bringing just enough moisture to prevent any scattering of the cloud deck. Persistent MVFR is expected over western Pennsylvania, while elsewhere clouds should remain borderline VFR near 4,000 ft. Conditions outside of lake effect snow will remain dry through Friday.

Outlook...

Thu PM...Lingering MVFR ceilings north and west. Fri..Mainly VFR. Friday Night...Restrictions in rain showers. Sat-Sun...Mainly VFR. Sun Night - Mon...Cold front passage, restrictions in rain; some wintry mix possible across the north.

CTP WATCHES/WARNINGS/ADVISORIES

None.