St. Agnes School, NY Hourly Weather Updates

Key Messages

As of 126 PM EDT Friday...

1. A couple showers today before dry weather tomorrow.

2. Periods of rain late Sunday into Monday.

3. Near seasonable temperatures with a chance for showers and thunderstorms mid week.

Discussion

... As of 126 PM EDT Friday...

KEY MESSAGE 1: A weak shortwave will pass through the region from northwest to southeast this afternoon and evening, but the strongest dynamics will mostly be to the south. An associated area of showers and embedded thunderstorms has developed west of Ottawa and those will move southeast into southwestern St. Lawrence County. A briefly stronger storm is possible there. The storms should mostly pass south of Rutland County, though a brief isolated shower is possible there. Pea sized hail and gusty winds are possible in the strongest storm in St. Lawrence County. After that, a gorgeous opener to the weekend will occur on Saturday with seasonably cool temperatures and low humidity.

KEY MESSAGE 2: A double barrel low will move into the region late Sunday into Sunday night, bringing rounds of rain. The primary low will track well north of the St. Lawrence, while the secondary low will try to spin up off the coast of southern New England, but they will both remain on the weaker side. The Euro ensembles generally bring the heavier rain associated with the southern low farther north and into the region, while the GEFS members generally split the region between the areas of low pressure and bring lighter precip. Overall, combined EPS/GEFS/CMCE probabilities of receiving more than a half inch are between 40-70 percent, and the probabilities of seeing more than an inch are less than 10 percent. Some convective enhancement is possible across southern areas, but no flooding is expected. Very weak lapse rates, a notable inversion and unfavorable timing should prevent much of a severe threat, though a trend north in storm track could still produce something, so the threat will continue to be watched. A few lingering showers are possible on Monday as a weak shortwave moves through under broad cyclonic flow.

KEY MESSAGE 3: High pressure and calm weather embedded in broad cyclonic flow will continue through Tuesday as temperatures slowly rise to near or just above seasonable levels. Highs will be in the upper 70s to low 80s heading into the mid week. Humidity will remain on the lower side Tuesday, but as flow shift slightly to the southwest by late Tuesday into Wednesday, some moisture advection is expected by mid week. The next weather maker will arrive by Wednesday into Thursday with a cold frontal passage. Models are in pretty good agreement for rain and possible thunder chances Wednesday afternoon for the higher terrain and into late Wednesday for most locations, however, how long showers linger remains in question. The GFS is the fastest of the model suite clearing the area of precipitation by Thursday afternoon. The Euro and Canadian favor a longer system, with more positive tilting to the trough axis, and precipitation persisting through the day Thursday. Regardless, pwats look to increase to around an inch, though where the best forcing sets up will determine how much of the precipitable water is realized. Temperatures mid to late week will slowly decrease from the low 80s to the upper 70s, along with a drying surface with dewpoints sinking back down to the low 50s.

Aviation

/00Z SATURDAY THROUGH WEDNESDAY/... Through 00Z Sunday...Calm and variable winds will continue as high pressure nudges in from the northwest. Outside of any variable winds, northerly flow aloft will prevail through the TAF period. Clouds are clearing after sunset with some patchy fog possible in the climatologically favored terminals. Winds likely will decouple at most sites and have trended favored sites towards prevailing fog tonight with 3SM BR to start. Highest confidence in prevailing fog is at SLK/MPV, though clearing skies and calmer winds bodes some confidence, albeit lower than SLK/MPV, for intermittent, potentially closer to sunrise, fog at EFK/RUT. Winds will need to be watched after sunset for any further calming trends that will increase or decrease fog chances, especially with any light easterly flow for BTV. Fog will lift between 12-13Z where it develops. Winds will become prevailing from the north-northwest after sunrise tomorrow with mostly clear skies.

Outlook...

Saturday Night: VFR. Patchy BR. Sunday: VFR. Chance SHRA. Sunday Night: Mainly VFR, with local IFR possible. Definite SHRA, Slight chance TSRA. Monday: Mainly MVFR, with local IFR possible. Chance SHRA. Monday Night: MVFR. NO SIG WX. Tuesday: Mainly VFR, with local MVFR possible. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. Chance SHRA, Slight chance TSRA.

Watches / Warnings / Advisories

/WARNINGS/ADVISORIES... VT...None. NY...None.