George BM

It might be just a tad bit cool for Christmas, actually. But we'll see. We may still warm up a few degrees. 56F at IAD right now as well.

Peanut Butter/Chocolate Protein Bars.

That's what pulled my arm enough for me to make the post about Sundays potential.

For the past several days I've been low-key watching the Sunday system for any severe potential and as of right now late Sunday has slight potential to get interesting should we have enough CAPE (which currently looks modest to perhaps locally moderate with LI of -3 to -5). Deep layer flow looks fairly strong (on the order of 50+ kts in the mid-levels). Should we be able to get enough sunshine for more moderate CAPE it could get interesting for some. Timing does look to be leaning a bit on the later side ATM. Then there is also still the question of how far north this 'threat' will extend. #Notanexpertopinion #Justmy2cents

Social Beering ftw.

Uphill we go slowly but surely. A spongy start.

Not too shabby.

It's the wind that you were denied on April 13th. 60/57 at IAD with a SE wind of 5kts. Light Rain.

Guesstimation of the strength of the wind gusts?

Eggs, Green Leaves, Mushrooms, Meatballs (Pieces?), Cheese. How far off was I?

I just noticed that ECMWF soundings are now behind a paywall on PivotalWx. Wow, what a game changer! Currently the temperature is 50 degrees with light rain/drizzle at IAD.

Yeah that supercell looks nasty. The dbz reflectivity with it was into the upper 70s last hour!

While just about all ensembles have this trough staying over the eastern US for the remainder of the month into the beginning May I wonder if we can get into some W/NW flow action sometime early in May (2nd week?) as the trough slowly lifts and/or shifts eastward (as shown in a number of long range ens. ATM). Just speculation at this point of course... and me thinking out loud.

A pretty decent gust-front just went through Charles Town looking at the radar. What would you guesstimate the strength of the gusts to be?

URGENT - WEATHER MESSAGE National Weather Service Baltimore MD/Washington DC 1140 AM EDT Tue Apr 21 2020 DCZ001-MDZ011-013-014-016>018-504-506-508-VAZ052>057-212345- /O.EXA.KLWX.FZ.W.0005.200422T0600Z-200422T1200Z/ District of Columbia-Southern Baltimore-Prince Georges- Anne Arundel-Charles-St. Marys-Calvert- Central and Southeast Montgomery-Central and Southeast Howard- Southeast Harford-Prince William/Manassas/Manassas Park-Fairfax- Arlington/Falls Church/Alexandria-Stafford-Spotsylvania- King George- Including the cities of Washington, Baltimore, Bowie, Suitland-Silver Hill, Clinton, College Park, Greenbelt, Laurel, Camp Springs, Glen Burnie, Annapolis, Severn, South Gate, Severna Park, Arnold, Odenton, St. Charles, Waldorf, Lexington Park, California, Chesapeake Beach, Huntingtown, Dunkirk, North Beach, Lusby, Prince Frederick, Bethesda, Rockville, Gaithersburg, Silver Spring, Columbia, Ellicott City, Aberdeen, Dale City, Manassas, Woodbridge, Lake Ridge, Montclair, Reston, Herndon, Annandale, Centreville, Chantilly, McLean, Franconia, Arlington, Alexandria, Falls Church, Falmouth, Fredericksburg, and Dahlgren 1140 AM EDT Tue Apr 21 2020 ...FREEZE WARNING IN EFFECT FROM 2 AM TO 8 AM EDT WEDNESDAY... * WHAT...Sub-freezing temperatures near 30 expected. * WHERE...Portions of The District of Columbia, central, northern and southern Maryland and central and northern Virginia. * WHEN...From 2 AM to 8 AM EDT Wednesday. * IMPACTS...Frost and freeze conditions will kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. To prevent freezing and possible bursting of outdoor water pipes they should be wrapped, drained, or allowed to drip slowly. Those that have in-ground sprinkler systems should drain them and cover above- ground pipes to protect them from freezing. && $$

The DC metro is now within the SLGT risk. 0% Tornado/ 15% Wind/ 0% Hail

Don't completely sleep on this Tuesday either. There could be some low-topped convection with limited CAPE along and just ahead of the cold front. Steep low-level lapse rates and fairly fast-flow aloft could translate to some of the convection having strong wind gusts.

Down to at least 30F at IAD this morning. Patchy frost.

This shows that we at least have a non-zero severe chance through the end of April.

Wait a minute?... What?!

Even the April 6, 2017 had fairly widespread strong winds and seven EF-0 tornadoes in northern VA... this with less than 250J/kg MUCAPE. That June 13, 2013 event could have been a memorable event area-wide if the morning MCS didn't hamper things. It was also the last time we had a moderate risk in the immediate region though it was downgraded to a SLGT at 1630z due to said morning MCS leaving us with AOB 1000 J/Kg MLCAPE. This is my opinion (not an expert): When dealing with a W/NW flow event with a fairly strong low-pressure system within the flow there will very often be a morning/early day MCS. This is because the previous days storms that develop in the Midwest often grow upscale during the evening and are able to survive the whole night due to the better dynamics and CAPE. With the forward speed that these MCSs usually have they very often reach us during the morning hours. An ideal thing with these regimes would be either the timing being a few hours faster so that we can get more midday/solar noon sunshine to destabilize the atmosphere more quickly for any later day activity (easier option) or a heat-dome already being in place so that any morning event would stay to the north while the low-pressure system approaches from the W/NW spawning another MCS (or just decent storms in general) during the afternoon to cruise through the region during the afternoon/evening (harder to pull off option).

Thank you both for the replies.

Sorry for the novice question but how do I read this? Is this showing the expected surface wind speed and direction at various times?

Mesoscale Discussion 0360 NWS Storm Prediction Center Norman OK 0426 PM CDT Sun Apr 12 2020 Areas affected...south-central and southeast Mississippi Concerning...Tornado Watch 106...107... Valid 122126Z - 122200Z The severe weather threat for Tornado Watch 106, 107 continues. SUMMARY...Based on recent radar and environmental data, a violent tornado with potential peak winds of 170 to 205 mph (EF4-EF5) is likely ongoing. THIS IS AN EXCEPTIONALLY RARE EVENT. DISCUSSION...An intense supercell will continue to move through a favorable environment over south-central Mississippi, characterized by 0-1 km SRH around 400 m2/s2 and MLCAPE near 2000 J/kg per latest mesoanalysis data. Recent radar signatures from KLIX as of 2112Z reveal an intense supercell characterized by a 0.4 degree rotational velocity of at least 70 kt. A tornadic debris signature has also been noted on recent radar scans. These signatures are occurring in an environment characterized by STP greater than 7. Previous signatures within similar environments produced tornado-damage-estimated wind speeds from 170 to 205 mph and confidence is high for a likely violent tornado. A long-track tornado is expected to continue based on the rotational velocity duration and the storm moving within a favorable downstream environment.

Also RAP'd.