textproduct: State College

WHAT HAS CHANGED

* Continue to advertise more snow vs rain to the north of I-80 Monday/Monday night in association with a clipper system dropping SE from the Great Lakes. * Increased sky cover to near 100 percent today and tonight across the Laurels and NW Mtns with a transition to decent breaks east of the I-90 corridor later this afternoon/early tonight.

KEY MESSAGES

1) Cold front pushing east of the Susq Valley with rain ending early this afternoon.

2) Light snow likely across the northern tier Monday/Monday night.

3) Much colder next week but warming up again at week's end.

DISCUSSION

KEY MESSAGE 1: Cold front pushing east of the Susq Valley with rain ending early this afternoon.

An approximate 4-6 hour period of light to briefly moderate rain fell along and just in the wake of a cold front this morning as a deep layer of uvvel accompanied the well-defined, thermally direct circulation linked to the right entrance region of a southwesterly upper level jet.

As the rain ends in the Scent Mtns and from the Susq Valley East early this afternoon, sct SHRA will return to the NW mtns as the primary mid/upper level trough moves east from Mich and Ohio. As the temps in the clouds and at the sfc get colder, the precip will become frozen and have little time/altitude above freezing to melt on it's way to the ground. There could also be a little graupel in a shower or two if they can tap a little CAPE. These SHSN will last into the first half of the night. Just a dusting of an accumulation is expected, mainly along and N of Route 6.

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KEY MESSAGE 2: Light snow likely across the northern tier Monday/Monday night.

A Clipper-like system dives down from Central Canada and across the Great Lakes on Monday. It has meager moisture to drop on Central PA, but numerous SHSN expected in the northern tier. More sparse showers (mixed) will make it south of I-80. Sfc temps are expected to get into the 40-45F range in the nrn tier in the aftn on Mon, so the p-type may be a mix, too. The NAM does paint some meager CAPE in the NW, too. So, there could be a briefly heavier spot of precip/snow here and there. At this point, it doesn't look dynamic enough to make serious snow squalls. However, the forcing looks strongest later in the day and evening Monday as a short wave trough passes overhead. A couple of models show the SHSN dipping into the Laurels in the evening. The SHSN will linger all night and perhaps into Tuesday AM until the (broad) axis of the upper trough moves past the CWA. Overall, the accums could be an inch or so in the nrn tier and perhaps a dusting in the Laurels and Alleghenies. Wouldn't be surprised to see a dusting on the ridge tops around Happy Vally by Tuesday AM.

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KEY MESSAGE 3: Much colder next week but warming up again at week's end.

Tuesday MA mins will be cold enough for frost over all of the area, but wind of 10-15 G 20-25KT will keep that from happening. The cold pool will be deepest on Tuesday, limiting max temps to the freezing mark near the NY border and 45-50F in the srn cities. These numbers will be about 10-12F below normals.

Wednesday morning will be the coldest this week due to the center of the sfc high being right overhead. Morning mins will be well below freezing everywhere. Even the Lower Susq will get into the L-M20s. The start of the growing season (date of the normal last spring freeze) is not until the 11th there. So, we probably won't be issuing frost/freeze products for that morning. But, collaboration with our neighboring WFOs will weigh heavily on that decision.

It then warms up close to normals maxes on Wed as the sfc high slides to our E and S and the wind turns to come out of the S and we should be sunny. Thursday looks much warmer, jumping another 10-15F over Wed's numbers. PoPs stay pretty low as we warm up as the sfc high noses back into the Deep South. That will help to keep moisture from the Gulf from getting to us.

AVIATION /15Z SUNDAY THROUGH THURSDAY/

Flight categories and LLWS will improve from west to east across the Central Ridge and Valley region of PA through this afternoon in the wake of a cold front.

MVFR ceilings are moderately likely (50-60%) to persist into the mid afternoon 19-20Z at KUNV and KAOO as colder drier air works in, while mainly VFR CIGS are expected to persist at the tail end of an area of rain and afterward across the Susq Valley.

Conversely, deepening cold air and the approach of an upper level trough will combine with orographic lift to increase the chc for SHRASN this afternoon and evening at KBFD and KJST with IFR to MVFR CIGS.

MVFR to briefly IFR CIGS will occur tonight into Monday at KBFD and KJST with ocnl -shsn. Variable MVFR to low end VFR bkn cigs will continue tonight acrs the Central Mtns with VFR at the Susq Valley Airfields.

Wind gusts from 270-290 deg later today and tonight could exceed 30 KTs at times, as the colder air pushes in beneath the subsiding (left rear) portion of an upper level jet max.

Outlook...

Mon...Breezy and cooler with MVFR N/W and VFR elsewhere, with scattered rain/snow showers possible.

Tue...Mainly VFR with a few rain/show showers.

Wed-Thu...VFR.

CLIMATE

Record high temperatures were set at the following locations on April 4th:

Harrisburg set a record high temperature of 83 degrees, breaking the old record of 82 degrees set in 1999. A continuous weather record has been kept in Harrisburg since 1888.

Bradford set a record high temperature of 77 degrees, breaking the previous record of 72 degrees set in 1981.

Altoona tied a record high of 80 degrees, where the previous record was set in 1950.

CTP WATCHES/WARNINGS/ADVISORIES

None.