Key messages
- 1) A strong cold front will bring gusty winds, showers, and a
What Has Changed
SPC has expanded the Marginal Risk slightly northward to encompass the Mohawk Valley, all of the Capital Region and most of southern VT. The Slight Risk area has been slightly expanded north to include portions of Greene/Columbia counties.
Key Messages
few thunderstorms to the region today. Continued gusty and unseasonably chilly conditions are expected tonight into Saturday. A coating of snow is possible in the high terrain late tonight into Saturday morning.
2) Dry weather with temperatures moderating to near seasonable levels Sunday into early next week.
Discussion
KEY MESSAGE 1...
A strong cold front will approach from the west today as low pressure tracks into the St. Lawrence River Valley. For early this morning, a warm front will approach from the southwest with bands of rain passing through ahead of the front at the leading edge of a strengthening low level jet. Strong forcing and some elevated instability will allow for some locally heavy downpours and rumbles of thunder to occur toward and shortly after daybreak, especially across the Mohawk Valley and southern Adirondacks, Capital/Saratoga and Lake George Region into southern VT. Rainfall rates of 0.25-0.50"/hour could lead to some ponding of water in poor drainage areas for the morning commute in these areas.
As the low level jet translates overhead around and shortly after daybreak, strong south to southeast winds will be possible across portions of the Capital Region and within some north/south oriented valleys. Latest REFs suggest some gusts of 30-40 mph could occur in these areas through mid morning before decreasing as the core of the low level jet passes by and weakens.
As the cold front approaches from the west during the afternoon hours, some surface-based destabilization should occur, especially if some breaks of sun can develop. Latest HREFs and REFs suggest SB CAPES of 100-250 J/kg developing for areas mainly south of I-90. Strengthening mid level winds will allow 0-6 km shear to increase to 50-60 KT amid this instability, parallel to the incoming front. This suggests the possibility of a low topped line of showers/thunderstorms to develop which could produce a few instances of damaging wind gusts. SPC has expanded the Marginal Risk (Level 1 of 5) for severe thunderstorms northward, now encompassing much of the Mohawk Valley, Capital Region and southern VT, with the Slight Risk (Level 2 of 5) expanding just slightly north into portions of Greene/Columbia counties. Even in the absence of convection, as the front passes through, some brief wind gusts of 35-45 mph will be possible this evening.
In the wake of the front, blustery conditions will develop tonight and continue into Saturday with northwest winds gusting 25-35 mph, perhaps a bit stronger Saturday morning as mixing deepens. Some lingering moisture in the wake of the front, partially from Lake Effect, will allow for some snow showers across higher terrain areas of the southern Adirondacks and southern VT late tonight into Saturday morning, where some coatings to less than one half inch of snow accumulation will be possible. A few flurries/sprinkles could even occur across the eastern Catskills, the Berkshires, and at lower elevations such as the Mohawk Valley and Capital Region Saturday morning. High temperatures Saturday should only reach the 30s to lower 40s across higher elevations, with mainly 40s for valley regions. Combined with brisk winds, wind chill temperatures ("feels-like" temperatures) will be in the 20s/lower 30s for higher terrain, and 30s in valleys through much of the day.
KEY MESSAGE 2...
After an unseasonably cold morning Sunday with low temps mainly in the 20s, temperatures should moderate into the 50s for most areas by Sunday afternoon. Temperatures will continue to moderate to seasonable levels early next week with highs reaching the upper 50s to lower 60s in valleys. Generally dry conditions are expected through Wednesday.
Aviation /12Z Friday Through Tuesday/
Through 12Z/Saturday...MVFR/IFR conditions through mid morning with periods of rain, some moderate to heavy in intensity. Mainly MVFR Cigs and VFR Vsbys are then expected later this morning through mid afternoon. A line of downpours along a cold front is anticipated to move through sometime between 19Z-24Z/Friday. Will mention PROB30 for IFR conditions associated with +SHRA at KALB/KGFL/KPSF, but due to some instability will mention +TSRA at KPOU. Cigs should generally vary between 3500-5000 FT AGL in the wake of the cold front for tonight. However, upslope winds may produce occasional MVFR Cigs at KPSF, where some sprinkles/flurries will also be possible.
Will continue to mention low level wind shear at all sites through early afternoon, as a southerly jet of 40-45 kt at 2000 ft AGL moves overhead with sustained surface winds generally less than 15-20 kt. The LLWS should dissipate by mid to late afternoon. Surface winds will be south-southeast at 8-15 kt most of today with gusts of 20-32 kt developing at KALB/KPSF. Winds will then shift into the west, then northwest late this afternoon with speeds of 8-15 KT and gusts of 20-30 KT. These winds should then continue overnight although there could be some periods where gusts subside at times at KGFL and KPOU.
Outlook...
Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX.
Aly Watches/Warnings/Advisories
CT...None. NY...None. MA...None. VT...None.
DISCUSSION...24/35 AVIATION...24/07