yoda Posted June 25, 2023 Share Posted June 25, 2023 Arlington, VA is in the hatched while DC is just outside lol https://www.spc.noaa.gov/products/outlook/day2otlk.html 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 25, 2023 Author Share Posted June 25, 2023 I know sim reflectivity is not the and-all-be-all...BUT - I've got to say that the guidance is now pretty consistently spitting out sim reflectivity panels that are the most impressive I've seen for this area in some time. Not this weak sauce isolated crap or a weak line...this looks like an actual threat if things come together correctly. 6 Link to comment Share on other sites More sharing options...
mappy Posted June 25, 2023 Share Posted June 25, 2023 Methinks I won’t be playing softball tomorrow 1 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 25, 2023 Share Posted June 25, 2023 37 minutes ago, Kmlwx said: I know sim reflectivity is not the and-all-be-all...BUT - I've got to say that the guidance is now pretty consistently spitting out sim reflectivity panels that are the most impressive I've seen for this area in some time. Not this weak sauce isolated crap or a weak line...this looks like an actual threat if things come together correctly. Worried that we see a drop off north of I-66. This seems like a Virginia and maybe Delmarva event. 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 25, 2023 Author Share Posted June 25, 2023 20 minutes ago, Eskimo Joe said: Worried that we see a drop off north of I-66. This seems like a Virginia and maybe Delmarva event. Always a risk! However, I'm cautiously optimistic that there aren't a ton of models (at least for now) that skunk big chunks of the area. A few DO favor south - but even those blow up good activity over the DC/Baltimore metros. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 25, 2023 Author Share Posted June 25, 2023 @Eskimo Joe - Not that it will alleviate your concerns of being shafted - but some models even focus a chunk of the activity NE of DC. HREF updraft helicity seems to show this. Some of the modeling seems to indicate there may be a dead-zone between a batch to the NE and a batch to the S. That could also be a failure mode for us locally... Link to comment Share on other sites More sharing options...
MN Transplant Posted June 25, 2023 Share Posted June 25, 2023 Paying attention to the DPs on the HRRR vs NAM. HRRR is much drier and the coverage is unimpressive. Is that a bias in convective scenarios this year? I haven’t been paying attention. 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 25, 2023 Author Share Posted June 25, 2023 8 minutes ago, MN Transplant said: Paying attention to the DPs on the HRRR vs NAM. HRRR is much drier and the coverage is unimpressive. Is that a bias in convective scenarios this year? I haven’t been paying attention. If my memory isn't failing me yet (it probably is) I do think that the HRRR had a tendency in past severe seasons to pull dew points way too far down. But I'm sure the NAM could be too moist. 2 Link to comment Share on other sites More sharing options...
high risk Posted June 25, 2023 Share Posted June 25, 2023 30 minutes ago, Kmlwx said: If my memory isn't failing me yet (it probably is) I do think that the HRRR had a tendency in past severe seasons to pull dew points way too far down. But I'm sure the NAM could be too moist. Yes, the NAM is typically too moist, but the HRRR absolutely overmixes. 2 Link to comment Share on other sites More sharing options...
high risk Posted June 25, 2023 Share Posted June 25, 2023 12Z CAMs are all over the place. Summary: NAM Nest FV3 HRRR ARW2 (for Howard County: ) ARW 4 5 Link to comment Share on other sites More sharing options...
southmdwatcher Posted June 25, 2023 Share Posted June 25, 2023 The new day 2 expanded the Enhanced Risk to cover DC/Baltimore and Philly/central NJ across eastern half of VA and down to Raleigh 1 Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 1 Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 2 minutes ago, southmdwatcher said: The new day 2 expanded the Enhanced Risk to cover DC/Baltimore and Philly/central NJ across eastern half of VA and down to Raleigh Link to comment Share on other sites More sharing options...
southmdwatcher Posted June 25, 2023 Share Posted June 25, 2023 No hatched areas on this Day 2 outlook, but the 30 percent wind and 2 percent tornado risk areas were significantly expanded. Link to comment Share on other sites More sharing options...
CAPE Posted June 25, 2023 Share Posted June 25, 2023 Pretty interesting sounding for here tomorrow evening on the 3km NAM. 2 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 25, 2023 Share Posted June 25, 2023 4 hours ago, MN Transplant said: Paying attention to the DPs on the HRRR vs NAM. HRRR is much drier and the coverage is unimpressive. Is that a bias in convective scenarios this year? I haven’t been paying attention. HRRR does mix things out a lot. It's a known bias. Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 This was from this morning LWX AFD... haven't seen them mention destructive winds before SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... After a lackluster start to the severe weather season, things quickly begin to change as a robust upper trough sweeps through the Ohio Valley to Mid-Atlantic. Presently, the upper low is situated over the Upper Midwest while eventually racing toward the east-southeast during the next 12 to 36 hours. With warm sector temperatures rising into the upper 80s/low 90s and dew points reaching the low 70s, ample instability will be available for convective development. Depending on the forecast model, surface-based instability nears 3,000 J/kg, accompanied by unusually steep mid-level lapse rates. With such lapse rates into the 7 to 8 C/km range, there is an increasing threat for large hail, especially from the D.C. metro southward. Additionally, large downdraft CAPE values are evident in forecast soundings which supports damaging to locally destructive winds. The latest model suites favor early afternoon convective initiation over the terrain as well as along a well established lee trough. Seasonably high CAPE values should allow rather quick development of updrafts. Within a couple hours after initiation, high-resolution models favor upscale growth into a eastward propagating squall line. The Storm Prediction Center has placed areas east of I-81 in a Slight risk for severe thunderstorms, with an Enhanced risk grazing Spotsylvania and King George counties. Depending on how subsequent models and observational data indicate, some expansion of these threat areas are possible. With an above average precipitable water air mass advecting into the region, there will be some threat for flash flooding. The cold pool driven thunderstorm activity should keep convection on the move. However, a quick inch or two is possible within many of these storms. A Slight risk continues from the Blue Ridge eastward, but especially over the DC to Baltimore urban sprawl. As the cold front does not arrive until late Monday into early Tuesday morning, some of these thunderstorms may linger into the overnight hours. Nighttime low temperatures will range from the 60s to low 70s. 1 Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 Baseball sized hail in IN in one of its STW Link to comment Share on other sites More sharing options...
Stormfly Posted June 25, 2023 Share Posted June 25, 2023 First enhanced for us since July 12, 2022 which in fact for many of us, did indeed verify. I just hope the tennis ball sized hail stays out of our yard this time around! Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 Afternoon AFD from LWX... and here we go @Eskimo Joe @high risk SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Closed upper-level low pressure will remain over the Great Lakes Monday and a potent jetmax associated with this system will move into the area during this time. This will cause the wind field aloft to increase while heights fall. A surface trough will most likely setup east of the Allegheny Front due to differential heating. Showers and thunderstorms are most likely to develop along the surface trough during the early to mid afternoon hours (approx 16-18z) before propagating eastward (additional showers and thunderstorms are likely west of the trough as well due to the breaking capping inversion from falling heights). Thunderstorms are expected to intensify as they propagate eastward, possibly congealing into linear segments that produce more widespread wind damage. Deep layer shear is progged to be around 25-40 kt, and mid-level lapse rates will be steep due to the falling heights. SBCAPE is progged to be around 1500-3000 J/KG with the highest amounts east of the Blue Ridge. DCAPE will most likely be over 1,000 J/KG for many locations, enhancing the threat for downbursts. Also, some of the fattest CAPE in the soundings is progged to be around the -20C level, suggesting that there is a potential for very large hail in addition to the damaging wind threat. Veering profiles also suggest that an isolated tornado is possible as well. Please pay attention to the latest forecasts for Monday afternoon/evening, and be prepared to seek shelter if warnings are issued. The most likely timing for severe storms is around noon to 4 PM west of the Blue Ridge Mountains, and 4 PM through 8 PM east of the Blue Ridge Mountains into the metro areas, and perhaps lingering until around 9 or 10 PM toward southern MD and the Bay. Convection should dissipate later Monday evening. However, if we do not get widespread convection during the afternoon/early evening, there is a threat for isolated to scattered severe storms well into the evening because the atmosphere will not be worked over. Overnight, most of the time should turn out dry with just an isolated shower or t-storm possible. 1 Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 So where are we on here? Still Yoda level? Or higher? 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 25, 2023 Author Share Posted June 25, 2023 I'm not officially on board yet. I'll take a look this evening. Link to comment Share on other sites More sharing options...
csnavywx Posted June 25, 2023 Share Posted June 25, 2023 Deeper mixing is indeed a failure mode here but the HRRR is probably overdoing it, esp if there is any debris in the morning from overnight activity. 1 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 25, 2023 Share Posted June 25, 2023 Keep it Yoda level. I'm not sold west of I-95. Link to comment Share on other sites More sharing options...
CAPE Posted June 25, 2023 Share Posted June 25, 2023 Latest disco on the severe threat from Mount Holly- Deeper convection is forecast to develop to our west near a pre- frontal trough. The model forecast soundings indicate some discrete cells out that way should quickly consolidate into a convective line as it shifts eastward. An examination of model point forecast soundings indicate ample instability developing along with rather steep low-level lapse rates, and the mid level lapse are on the steeper side as well. The shear profiles are somewhat on the weaker side, however model soundings show some initial backed low-level flow with around 30 knots of shear. This would be enough when combined with strong forcing for ascent arriving for the risk for severe thunderstorms. Storms should organize into a line as it approaches our region with damaging winds and some hail the main threats. Given the backed near surface flow ahead of the line, cannot rule out some rotation within the eastward advancing squall line (QLCS) especially across Delmarva. CAM guidance shows convection quickly becoming linear, with even some hinting at strong outflow winds. Given the steep low-level lapse rates, downdraft instability (DCAPE) should be on the high side, which will enhance convective winds down to the surface especially associated with any forward surges in the line. With increased confidence in linear thunderstorm segments capable of producing damaging winds forming, the Storm Prediction Center now has much of our area south of the I-78 corridor in an Enhanced risk (level 3 of 5) for severe thunderstorms on Monday. 1 Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 Severe wording put in the ZFPs Link to comment Share on other sites More sharing options...
Kmlwx Posted June 25, 2023 Author Share Posted June 25, 2023 Not questioning the SPC - but I would have held off on that hatching until a subsequent outlook. Adding it on the initial D2 and removing it on the updated D2 is less ideal than just leaving it off until confidence is higher. As others have already said - I think the failure modes for us are still present. The mid-level lapse rates (if they come to fruition) should at least be able to give us some "wiggle room" for exciting weather. Unless we get a huge squall line stretching the entire area - some places (as always) will get shafted. That being said...my thoughts remain largely unchanged. I think this is our best severe weather threat in some time now. If the NAM moisture and HRRR moisture met in the middle - probably would still yield a decent setup. All will come down to nowcasting as it often does here. Will be interested to see how the models look at the 0z suite and even the 6 and 12z runs tomorrow. Lots of eyes will be on the dewpoints during the morning and the mesoanalysis page. I know we all cringe at trying to "forecast" the SPC. But I'd put my two cents in that the D1 outlook overnight for tomorrow will be largely unchanged from right now - unless guidance suggests some huge change or outbreak. Wouldn't be surprised to see the hatched hail come back at some point - the SARS analog data getting spit out on some forecast soundings is quite impressive on hail size. OT - but tomorrow is one of my in-office days of the week. And I'm in until 5:30pm...really hoping I can either duck out early...doubt it, though. 8 1 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 25, 2023 Share Posted June 25, 2023 Big red flag for tomorrow.is how underwhelming the event has been today in the Midwest. Was expected to be a squall line, instead it's mostly clusters. 2 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 25, 2023 Author Share Posted June 25, 2023 5 minutes ago, Eskimo Joe said: Big red flag for tomorrow.is how underwhelming the event has been today in the Midwest. Was expected to be a squall line, instead it's mostly clusters. Weenie-ism = It's underperforming today so that the juice can be saved for our event tomorrow. 2 1 Link to comment Share on other sites More sharing options...
yoda Posted June 25, 2023 Share Posted June 25, 2023 8 minutes ago, Eskimo Joe said: Big red flag for tomorrow.is how underwhelming the event has been today in the Midwest. Was expected to be a squall line, instead it's mostly clusters. A more cellular event could lead to a better chance of large hail over damaging winds 3 Link to comment Share on other sites More sharing options...
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