textproduct: State College

WHAT HAS CHANGED

* Minor modifications made for this forecast cycle.

KEY MESSAGES

1) Chilly Memorial Day weekend with periods of rain/drizzle. Record challenging cold max temperatures almost a slam dunk today in many locations across Central PA.

2) Temperatures trend warmer into the middle of the week, but scattered showers and thunderstorms remain possible.

DISCUSSION

KEY MESSAGE 1: Chilly Memorial Day weekend with record challenging cold max temperatures almost a slam dunk today in many locations across Central PA.

Primary belt of anomalous east-southeasterly flow at 850 mb will be shifting North and East of the CWA through early this evening, carrying away the steadiest and heaviest rain with it.

The anomalous ESE flow in the 925-900 mb layer (and llvl CAD regime) stays in tact longer over the region, before winds in that layer gradually veer more to SE then SSE respectively tonight and Sunday.

Expect a 4-6 hour lull in the rain over the western half of Pennsylvania, with just a few brief showers or patchy drizzle. Less of a gap in the periods of rain will occur across the Susq Valley and points east.

The evolution of these speed maxes at 925-850 mb will continue to support periods of lighter rain/drizzle late this afternoon and tonight, but still some brief times of moderate rainfall rates are expected, especially over the Laurel Highlands and Lower Susq Valley.

All of this rain is expected to largely be beneficial, particularly for locations that are experiencing D1/D2 drought.

Scattered showers will be possible through the day on Sunday, but rain is not expected to be nearly as widespread as it is today. Another disturbance will track through the region late Sunday into Monday, potentially bringing another round of steady rainfall along with it.

The moderately gusty east/southeast wind will make it feel downright dreary/raw, unseasonably chilly and pretty miserable for this time of year - especially for outdoor activities through Sunday morning. High temperatures today will range from the mid 40s to the low 50s with winds gusting between 20 and 35 mph at times.

The 2-3 day cool stretch will certainly be noticeable following an early taste of summer, but it won't have staying power with temperatures forecast to moderate and trend above normal into the middle of next week.

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KEY MESSAGE 2: Temperatures trend warmer into the middle of the week, but scattered showers and thunderstorms remain possible.

Temperatures become much warmer for Monday with highs expected to be in the mid to upper 70s as the CAD wedge begins to move out of the area. The warming trend continues into the middle of the week, with highs expected to be in the upper 70s and low 80s by Wednesday. While widespread rainfall does not appear likely, a few showers or possibly a thunderstorm will be possible each day. There is some signal for temperatures to drop back into the 60s and low 70s by the end of the week as high pressure begins to build in from the north.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Large area of steady light to moderate stratiform rain that impacted the region during the early to mid morning hours will lift north and east of the Central PA airfields through early this evening. Just a few periods of generally lighter rain and drizzle will occur late this afternoon and early this evening across the airfields of KBFD, KJST, KAOO and KUNV.

Widespread IFR and some periods of MVFR will prevail for the rest of this afternoon and lower to mainly IFR/LIFR by late this evening and continue overnight.

In terms of winds, breezy winds are expected to pick up at all airfields tonight. Highest gusts (20-30 kts) are expected in the Laurel Highlands and NW mountains, with a secondary max near the Susq Valley.

Despite gusty surface winds, a very strong low level jet aloft will lead to LLWS concerns at all airfields through the majority of the current 18Z TAF package - at least until around daybreak Sunday.

Outlook...

Sun...Minor improvement to MVFR/IFR restrictions as rain tapers off by around noon

Mon...IFR/MVFR early, then MVFR in light rain showers

Tue...Possible morning fog/low visibility, then VFR.

Wed...Mainly VFR, some scattered SHRA could bring restrictions.

CLIMATE

Daily Record Low Maximum & Forecast Temperatures for May 23:

LOCATION RECORD (YEAR) FORECAST HIGH Harrisburg 54 (1982) 52 Williamsport 57 (1982) 50 Altoona 52 (2005) 49 Bradford 45 (1963) 46 State College 53 (1968) 49

CTP WATCHES/WARNINGS/ADVISORIES

None.