textproduct: State College

WHAT HAS CHANGED

* No significant changes

KEY MESSAGES

1) Best weather day of the week underway with highs near 70 this afternoon

2) Periods of rain Tuesday and Wednesday will precede a cool pattern shift with below average temperatures into early May

DISCUSSION

KEY MESSAGE 1: Best weather day of the week underway with highs near 70 this afternoon

Today will be the pick (warmest/nicest day) of the week with plenty of sunshine sending max temps 10-15 degrees higher vs. Sunday. Departing high pressure sfc pattern along with steep llvl lapse rates supported leaning lower on dewpoints and corresponding minRH.

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KEY MESSAGE 2: Periods of rain Tuesday and Wednesday will precede cool pattern shift with below average temperatures to begin May

The preponderance of model data supports two periods of wet weather Tuesday and Wednesday. QPF amounts are more robust on Wednesday tied to stronger frontal wave with 48-hr totals in the 0.75-1.50" range ending 12Z Thursday. This rain will continue to add to surpluses over the NW half of the area while helping to reduce rainfall deficits in the southern 1/3 of CPA where D1-D2 drought areas have been persistent. However like we've seen time and time again so far this year, the highest totals are expected in the northwest.

SPC D3 MRGL risk valid Wednesday clips the Laurels as a 1003 mb sfc low swings through the area. Guidance seems to suggest only limited amounts of instability, confined to SW PA. NBM has 70-80% chc of at least 200 J/kg SBCAPE in SW PA but only a 30% chc of 750+ J/kg. Storm motions would be to the northeast, so storms would be moving into a less favorable environment as they move into PA. Large scale forcing will be favorable for ascent for 6-12 hours across all of central PA as we'll be beneath the left exit region of an upper jet max.

Latest guidance has a good handle on the mid-larger scale pattern evolution from late week into the weekend (end of April into early May) showing a broad upper trough/low over the Great Lakes into the Northeast. This unseasonably cool cyclonic flow pattern will deliver below normal temps (5-15 degrees) and maintain daily shower chances with breezy conditions (wind gusts 25-35 mph) Thursday through Sunday. Odds favor advective freeze over frost risk with wind and cloud cover playing a key factor.

AVIATION /18Z MONDAY THROUGH SATURDAY/

High pressure along the East Coast will maintain dry weather and VFR flight conditions through 12Z Tuesday, with gusty ridgetop winds emerging after sunset as a LLJ develops ahead of a low pressure system to our northwest. LLWS is most likely at KBFD, closer to the core of this jet, with shear being marginally favorable at KJST/KAOO/KUNV.

Otherwise, ceilings will lower west-to-east ahead of this system, with MVFR restrictions becoming more likely as rain/showers move in & moisten the low levels.

Outlook...

Wed...MVFR/IFR favored due to low cloud ceilings & rain overspreading the region.

Thu...VFR/MVFR overnight as rain ends west to east, becoming VFR in the afternoon.

Fri...VFR favored with restrictions possible in showers.

Sat...VFR favored with restrictions possible in rain/showers.

CTP WATCHES/WARNINGS/ADVISORIES

None.