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Updraft Helicity Index

@Ginx snewx would you happen to have a snowfall total recorded for Jan 7-8 1996? I dunno how far your records go back but you gave me Dec 2000 so i thought maybe you might have one.

Yeah it’s ripping right now. We still have 10+ hours to go according to the HRRR

Hi sorry, just seeing this. Was at a concert last night. I see it’s all been handled. Thanks for starting a thread

Urban heat island? lol

So SEPA can anticipate at least some wicked thunderstorms right?

Pretty big numbers for sure. One model NAM 3K, but this brings attention here in the Triad area.

Guidance has also backed off on the blocking a bit.

This new band should help the totals a bit. All depends on how long it sticks around. Really coming down right now. .

Webcam for Marquette:

never said otherwise, but it’s especially important for this event. Good thing that doesn’t look to be the case here (with the first band anyhow), though seems to be setting up a bit farther south than modeled, so the heart of the TC metro may miss out on the biggest totals.

Pity that MSP isn’t the bullseye but this should still end up with substantial totals at the airport. Going to go out and do round 1 of shoveling and measure soon.

Cross posting in here

06z HRRR had a UHI track from Dulles right to York, PA, another right over DC< and two more through Stafford and La Plata. Wow.

lol, so bad

NOAA is downplaying any snow potential.

Great Irish like day for the New Haven parade...

WB 6Z 3K NAM for Monday evening starting at 5 pm

Hrrr a little more tepid. Last time it did this is was closer to correct. We’ll see if it ramps up as we get closer.

We have been upgraded to a Moderate Risk. 15% tor and 60% wind.

It’s been a rough finish to winter. That’s for sure.

SPC ...Carolinas into MD/PA and vicinity... Areas of showers may occur early in the day especially but should rapidly lift north, allowing areas of heating and gradual destabilization over the entire area. As the surface trough deepens, low-level wind will back and strengthen throughout the day. Supercells producing tornadoes appear most likely ahead of the cold front from SC into NC and southern VA. Models vary with degree of instability, but strong tornadoes do appear possible with effective SRH of at least 300-400 m2/s2. Fast storm motions over 50 kt suggest a long tracked tornado will be possible. Meanwhile, a robust line of storms will develop as the cold front pushes east, stretching from the Carolinas to southern NY. With a moist air mass and large-scale support, this line is expected to produce particularly damaging winds, along with QLCS tornadoes across the remainder of SC/NC, VA, MD, and much of southern PA. This will likely peak during the late afternoon hours. The activity may eventually interact with cool trajectories off the Atlantic during the evening.

Latest Day 2 from the SPC. 45-60% hatched wind for most, greatest tornado risk is just to the west across south-central PA where a 10-15% hatched risk is outlooked. Given the extremely high shear but low cape environment, damaging QLCS winds will be favored but there will be line mergers and perhaps a few lone cells capable of a stronger tornado. The failure modes I'm seeing are 1. Given the potency of the upper-level trough, there may be "too many" showers and storms developing and competing with each other pre-frontal 2. Early day clouds and showers will limit destabilization 3. Strong southerly winds may or may not create a localized "minimum" in severe weather across SE PA where a narrow marine layer could advect off the Chesapeake Bay Regardless, we haven't seen a severe weather event of this caliber in at least a few years. It will get very cold again behind the front, so make sure if you lose power you have a plan