textproduct: State College

WHAT HAS CHANGED

* The Wind Advisory has been expanded into Clearfield and Blair counties and extended through 7 PM. * The threat for strong thunderstorms today has greatly diminished.

KEY MESSAGES

1) Windy conditions expected today, with highest wind gusts across the Laurels where a Wind Advisory remains in effect.

2) After dry weather for Friday and the weekend, rain returns to the forecast for Monday.

DISCUSSION

KEY MESSAGE 1: Windy conditions expected today, with highest wind gusts across the Laurels where a Wind Advisory remains in effect.

Anomalously strong surface low pressure tracking into southern Quebec will result in a windy afternoon (especially by June standards with near-record low MSLP to our north). Recent forecast outlines widespread maximum wind gusts between 35-45 mph this afternoon, and gusts up to 50 mph possible in the Laurels. Given recent upstream obs, we expanded the Wind Advisory into Clearfield and Blair counties, and extended the advisory in time through 7 PM this evening.

In terms of convection, the threat for strong storms has greatly diminished thanks to unimpressive midlevel lapse rates, low level dry air advection/mixing down of dry air, and the best forcing now moving up into New England. However, scattered showers are possible in the northern tier as the cold front approaches this afternoon and evening.

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Key Message 2: After dry weather for Friday and the weekend, rain returns to the forecast for Monday.

Following the passage of the cold front this evening, the remnants of TC Arthur will meet up with the frontal system to our south late tonight into early Friday morning. The northern periphery of this disturbance could produce a few hundredths of an inch of rain in the Lower Susq valley, ending by 10 AM Friday.

Fri and Sat will remain breezy but not as windy as Thu. Winds will be from the west with gusts 20-30 mph. With troughing aloft, expect temps to be just a few degrees below avg and lots of diurnal cumulus, but dry low levels should prevent anything more than a stray sprinkle from making it to the ground.

The next chance for more widespread rainfall will come on Sunday night and Monday as a wave of low pressure rides along a lifting warm front. Latest model consensus is for 1.00-1.50" of rain with this system before trending drier towards the middle of the week. However, given the relatively small size of this disturbance, we'll have to keep a close eye on bust potential if the track changes and brings the heaviest rain elsewhere.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Cold front is making its way into PA with some gusty showers in N PA at the moment. However, this activity isn't expected to become much more widespread as subsidence behind the main forcing area and dry air mixing are hurting precipitation chances. Spotty showers remain a small possibility at BFD in the next hour or so, but nothing appears to be prevailing at this time. Ceilings look to be mostly VFR, say for BFD past 06Z where guidance is indicating some upper bound MVFR as a postfrontal cloud deck builds in. Any restrictions should leave by daybreak.

The main threat this afternoon into the evening is the anomalously strong flow in the low levels mixing down to yield gusty conditions. We have seen consistent gusts >35kts with some non-TAF sites gusting past 40kts, which is possible this afternoon. Prevailing gusts should lower after 22Z, however they will still be high enough (15kts-25kts) to warrant mentions in FM groups after sunset. The flow should mostly be out of the west with a slight northerly component.

Outlook...

Fri-Sat...VFR with no significant weather.

Sun...Showers and thunderstorms developing in the afternoon/evening across the far west.

Mon...Restrictions possible with widespread showers and thunderstorms.

Tue...Lower chances of showers, mainly VFR.

CTP WATCHES/WARNINGS/ADVISORIES

Wind Advisory until 7 PM EDT this evening for PAZ017-024-025- 033-034.