textproduct: Binghamton

WHAT HAS CHANGED

Added chances of rain and snow showers this afternoon. Some of the showers this afternoon could contain graupel. Small adjustments to the snowfall for Northern Oneida county with the clipper system tomorrow into Saturday morning.

KEY MESSAGES

1) Late winter conditions return today and tonight following the passage of a cold front. Scattered afternoon showers are expected and may include graupel and gusty winds.

2) A clipper system arriving tomorrow and lasting into Saturday will bring a chance of mixed rain and snow, along with gusty winds. Accumulating snow will mainly affect higher elevations in the Southern Tier and areas south of it, with the Southern Tug Hill having the best chances for significant accumulation.

3) Another warmup expected late weekend as a stronger low pressure system moves into the Great Lakes region bringing another large swing in temperatures early next week.

DISCUSSION

KEY MESSAGE 1...

Strong cold air advection today will keep temperatures about 30 degrees cooler than they were yesterday. Higher elevations will struggle to get above freezing today but valleys and low elevations should still get into the mid to upper 30s this afternoon. The combination of cold air aloft and bare ground now that the snow has almost all melted leads to some afternoon instability so chances of rain/snow showers were added to the grids. Due to steep lapse rates and lower wet bulb temperatures, snow was added for anywhere that was below 37 degrees. With the convective nature of the showers this afternoon, the stronger cells that develop may have some graupel or small hail. A flash of lightning cant be ruled out, but thunder was not added to the weather grids for this afternoon. Lake effect was more uncertain even though 850 mb temperatures fall below -10C as the afternoon instability likely prevents any organized band from forming. A more organized band may form in the early overnight hours tonight but the 850 mb ridge builds in quickly so the window for lake effect snow is small and limited to along and north of I-90.

KEY MESSAGE 2...

As has been common this winter, another fairly strong clipper system forms in the front range of the northern Rockies later today and moves into the Great Lakes region tomorrow. Now that we have more warm air and a stronger sun, the precipitation for the Southern Tier and southward looks like more rain to a rain snow mix above 1200 feet as temperatures rise to the upper 30s to mid 40s prior to precip arrival. North of the Southern Tier stays a little cooler aloft looking at forecast soundings so precipitation type may be more snow than rain. Downslope areas like the I-90 corridor may warm enough to start as rain and change to snow later in the day.

Overall there is not a ton of moisture for the clipper to work with, so most of the area will see less than a tenth of an inch of QPF. CAMs are adamant that there will be upslope enhancement in the Southern Tug Hill in Northern Oneida county. Forecast soundings are a bit more iffy with the best lift below the dendritic growth zone under the warm air advection during the day Friday. Friday night into Saturday morning looks better for lake enhanced upslope as the clipper passes through and cold air advection takes over. Advisory level snow does look like a good possibility, but given the poor sounding profile under the warm air advection part of the storm, there is not enough confidence in warning criteria for snow, so no watch was issued for Northern Oneida. There also have been several set ups similar to this clipper so far this year that have underperformed relative to models for the southern Tug Hill.

KEY MESSAGE 3...

After another cooler day on Saturday behind the departing clipper system, another low develops in the central US. Models have come into good agreement in a strong Colorado low forming in the high plains and deepens as several 500 mb shortwaves phase with the digging trough in the central US trying to become negatively tilted. As the lows central pressure drops in the 980s mb to possibly the high 970s mb Sunday into Monday, a strong warm front lifts into the Northeast. Temperatures rise back into the 50s and 60s with gusty south winds Monday.

Given that we are in the warm sector of the low with strong vertical shear, there is the potential for some stronger storms Monday. Forecast soundings do have a strong inversion with cloud cover. If this cloud cover remains in the warm sector it will be tough to destabilize but if there can be enough clearing ahead of the cold front passage, enough instability could form to get a few surface based storms. The cold front passage itself will have enough convergence for a line of showers or thunderstorms to form along it though the timing of the frontal passage will determine the strength of the squall with an afternoon or evening passage providing the best chance for strong gusts to mix to the surface.

Similar to this current system, Tuesday and Wednesday next week looks cold with highs struggling to get out of the 20s and 30s.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Following the passage of a cold front, post-frontal low clouds will bring widespread MVFR to Fuel Alternate ceiling restrictions through at least this morning. Gradual improvement is expected by this afternoon with a return to VFR for most terminals. Low ceilings may linger until the mid-late afternoon at KITH, and especially at KSYR and KRME. There will be a potential for some light snow showers or graupel this afternoon, but confidence was not high enough to include in the TAFs at this time.

Gusty northwest winds are expected throughout the period with occasional gusts up to 30kts possible at times. Winds will gradually diminish this evening.

Outlook:

Friday through Friday night...Occasional restrictions possible in rain and snow showers.

Saturday...Mainly VFR.

Sunday through Monday...Occasional restrictions possible in rain and snow showers.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...Flood Watch until 5 PM EDT this afternoon for NYZ009-037.