yoda Posted May 19, 2019 Share Posted May 19, 2019 On 5/19/2019 at 10:29 PM, Kmlwx said: Thursday continues to look interesting on CIPS and GFS. Expand 12z looked same as 00z I guess re CIPS? Link to comment Share on other sites More sharing options...
Kmlwx Posted May 19, 2019 Author Share Posted May 19, 2019 Thursday looks like our next good potential for something organized. Link to comment Share on other sites More sharing options...
frd Posted May 20, 2019 Share Posted May 20, 2019 From Mount Holly for today, and I noticed a 90 degree reading possible in Southern Delaware. Looks like severe potential lower but the odds of getting into some thunderstorm activity better than yesterday 000 FXUS61 KPHI 201026 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 626 AM EDT Mon May 20 2019 .SYNOPSIS... A cold front associated with low pressure moving through the Great Lakes into Canada will cross our region this afternoon and evening. High pressure is then expected for Tuesday into Wednesday. A warm front arrives in our area late Thursday night and Friday, followed by a cold front on Saturday which may stall to our south on Sunday. .NEAR TERM /UNTIL 6 PM THIS EVENING/... A quiet start to the morning after a muggy and humid night. Temperatures will once again be on the rise, with most places making it into the mid to upper 80s. Portions of southern Delaware and the Eastern Shore of Maryland may in fact reach 90. Slightly cooler along the shore and in the higher terrain of the Poconos with highs in the mid to upper 70s. Another chance for showers and thunderstorms this afternoon as a cold front moves southeastward across the mid-Atlantic. The severe threat appears to be lower than yesterday, though non- zero. The Storm Prediction Center has our area under a Marginal Risk for severe thunderstorms. Instability looks to be lower than yesterday with ML CAPE values forecast to top around 2000 J/kg. Shear will be a little lower as well, with 0-3 km shear forecast to be less than 30 knots, thus a little less supportive of stronger thunderstorm cells. With the timing of the front, storms look to fire a little further southeast than yesterday, likely initiating along the Delaware River Valley by 4 to 5 pm and moving offshore by 9 to 10 pm. There could be some localized flooding concerns in areas that see brief heavy rainfall, but storm motion should prevent as much training as was seen yesterday. Link to comment Share on other sites More sharing options...
frd Posted May 20, 2019 Share Posted May 20, 2019 Marginal risk today, here but wow to the High Risk in Oklahoma and Texas. Going to be some incredible videos coming from that area. I am sure some of the best storm chasers in the country are there today, as it has been talked about for over a week, due to the high potential for large and long track d tornadoes. 1 Link to comment Share on other sites More sharing options...
mappy Posted May 20, 2019 Share Posted May 20, 2019 On 5/18/2019 at 10:22 PM, Kmlwx said: Sunday doesn't look that impressive anymore locally. But we are close to a slight from SPC. We'll see. Meanwhile - looks like Ian and our guys are in for a nice chasecation! Expand they have done well so far. saw a couple tornadoes friday, some structure saturday then traveled yesterday. looks like they will be in the texas panhandled area today. doubtful they head towards OKC. Link to comment Share on other sites More sharing options...
yoda Posted May 20, 2019 Share Posted May 20, 2019 12z NAM looks okay I guess for Thursday afternoon Link to comment Share on other sites More sharing options...
frd Posted May 20, 2019 Share Posted May 20, 2019 On 5/20/2019 at 1:27 PM, mappy said: they have done well so far. saw a couple tornadoes friday, some structure saturday then traveled yesterday. looks like they will be in the texas panhandled area today. doubtful they head towards OKC. Expand I believe I read many schools have been cancelled in the high risk areas today out West due to the nature of the forecast, timing of the storms, and the probabilities of extensive severe weather and tornadoes. Link to comment Share on other sites More sharing options...
mappy Posted May 20, 2019 Share Posted May 20, 2019 On 5/20/2019 at 3:11 PM, frd said: I believe I read many schools have been cancelled in the high risk areas today out West due to the nature of the forecast, timing of the storms, and the probabilities of extensive severe weather and tornadoes. Expand yes, public schools closed out there today. OU closed too. Link to comment Share on other sites More sharing options...
Kmlwx Posted May 20, 2019 Author Share Posted May 20, 2019 On 5/20/2019 at 2:56 PM, yoda said: 12z NAM looks okay I guess for Thursday afternoon Expand SARS has been showing some sig hail matches for Thursday PM. Too far out to say anything at this point - but between CIPS and the models generally suggesting a severe weather threat - it bears watching. I'm hardly watching our area for today - all eyes are on the plains. Link to comment Share on other sites More sharing options...
nj2va Posted May 20, 2019 Share Posted May 20, 2019 On 5/20/2019 at 3:11 PM, frd said: I believe I read many schools have been cancelled in the high risk areas today out West due to the nature of the forecast, timing of the storms, and the probabilities of extensive severe weather and tornadoes. Expand That was a wise decision to close schools today...hope everyone out there stays safe. Link to comment Share on other sites More sharing options...
frd Posted May 20, 2019 Share Posted May 20, 2019 Pretty crazy sounding there Link to comment Share on other sites More sharing options...
frd Posted May 20, 2019 Share Posted May 20, 2019 Mount Holly update at 330 PM NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... A very warm/hot and also humid afternoon in progress with some areas closing in on 90 degrees, however the dew points have dropped a little mainly along the I-95 corridor. An upper-level trough will continue to shift eastward through tonight from the Great Lakes, adjacent Canada and New England. Low pressure will track well to our north, however its cold front crosses our region through early this evening. As the cold front arrives, it may combine with a lee side trough. The convection allowing models (CAMs) generally agree that convection continues to develop, especially around the Philadelphia metro southwestward. In addition, some other convection will continue to develop especially near terrain influences and near the residual lee side trough. As of 19z, only some showers with no lightning being detected as convective development is shallow thus far. Visible satellite imagery does show some taller cumulus near and west of I-95. For now went no higher than scattered convection (chance PoPs), as the overall organization should be lacking. The latest mesoscale analysis shows around 500-1000 J/KG of MLCAPE and this should increase to around 1500 J/KG by late afternoon. The 0-3KM shear ranges from 30-40 knots with the strongest across the far northern areas. Some strong storms are anticipated with a few potentially going severe. There is some dry air aloft and combined with steeper low-level lapse rates results in better DCAPE and potentially strong surface winds. Locally strong to damaging wind gusts are possible, however this threat looks to be with any robust convective cores as precipitation loading will enhance the downdraft. There is not a lot of forcing, thus convection will be driven by the airmass and the incoming surface front. Once the cold front shifts offshore early this evening, the convection will end with clearing taking place. Cold air advection increases in the wake of the cold front, and this should keep some wind going from the northwest. This will also result in a cooler overnight, especially as the dew points drop into the 40s for much of the region by daybreak. Low temperatures are mainly a MOS/continuity blend. Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 Slight risk for Thursday for northern parts of the area. Then we have a 15% extended outlook nearby for day 5 (not yet in our area). Looks like LWX is pretty bearish on the weekend. SARS continues to print out some hefty analogs for Thursday, though. Some big hail showing up. We'll see how it pans out. Link to comment Share on other sites More sharing options...
high risk Posted May 21, 2019 Share Posted May 21, 2019 On 5/21/2019 at 11:31 AM, Kmlwx said: Slight risk for Thursday for northern parts of the area. Then we have a 15% extended outlook nearby for day 5 (not yet in our area). Looks like LWX is pretty bearish on the weekend. SARS continues to print out some hefty analogs for Thursday, though. Some big hail showing up. We'll see how it pans out. Expand I'm in for Thursday, especially after seeing the NAM nest forecast soundings and simulated reflectivity, although I like areas north of our region even better. 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 On 5/21/2019 at 3:20 PM, high risk said: I'm in for Thursday, especially after seeing the NAM nest forecast soundings and simulated reflectivity, although I like areas north of our region even better. Expand Yeah - it definitely seems like north is the better location for storms - and this is reflected in the slight risk area from SPC. Link to comment Share on other sites More sharing options...
yoda Posted May 21, 2019 Share Posted May 21, 2019 On 5/21/2019 at 3:20 PM, high risk said: I'm in for Thursday, especially after seeing the NAM nest forecast soundings and simulated reflectivity, although I like areas north of our region even better. Expand 12z NAM soundings look good as well IMO, esp between 21z THUR and 03z FRI Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 SARS is also still kicking back a lot of large hail matches on some runs. Link to comment Share on other sites More sharing options...
yoda Posted May 21, 2019 Share Posted May 21, 2019 On 5/21/2019 at 3:20 PM, high risk said: I'm in for Thursday, especially after seeing the NAM nest forecast soundings and simulated reflectivity, although I like areas north of our region even better. Expand I wonder if that action on sim reflectivity in SW PA/W MD would reach us in the few hours after the 12z NAM NEST run ends Link to comment Share on other sites More sharing options...
high risk Posted May 21, 2019 Share Posted May 21, 2019 On 5/21/2019 at 3:26 PM, Kmlwx said: SARS is also still kicking back a lot of large hail matches on some runs. Expand I'm not surprised. The lapse rates look quite healthy for the east coast, and the shear profiles (as currently modeled) would support splitting supercells. 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 On 5/21/2019 at 3:29 PM, high risk said: I'm not surprised. The lapse rates look quite healthy for the east coast, and the shear profiles (as currently modeled) would support splitting supercells. Expand There's even been some SARS matches of 4.5in hail - Hail is one of those harder things to come by around these parts. Every now and then a swath will get absolutely plastered. Time will tell for Thursday! 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 CIPS at the 60hr mark on the 12z run has some robust events showing up in the analogs. 5/14/2010 - which appears to have been a big day for hail around the area. 6/24/1996 which had some local tornadoes among the other reports. 6/23/2015 - which had wind damage in the area. 1 Link to comment Share on other sites More sharing options...
yoda Posted May 21, 2019 Share Posted May 21, 2019 LWX afternoon AFD on Thursday afternoon threat: Quote For Thursday afternoon, a southwest flow behind the warm front will bring a return to hotter and more humid conditions. Max temps will top off well into the 80s for most areas, and some areas may even approach 90 degrees. The increased heat and humidity will lead to an unstable atmosphere, and with our area between an upper-level high to the south and upper-level low to the north, there should be moderate amounts of deep layer shear. At the same time, a cold front will be approaching from the north but latest guidance keeps this boundary well to our north during peak heating before it drops down later Thursday night. Therefore, the timing of the boundary and peak heating are offset a bit. Having that been said, it will be a differential advection pattern (northwest flow aloft and southwest flow at the low-levels), which supports the development of convective systems (MCS). Will carry the chance for showers and thunderstorms Thursday afternoon and evening, and with the instability and shear in place, some of those storms could be severe. However, confidence still remains low due to uncertainty in timing of a convective system and also with the cold front arrival being after peak heating. The boundary will settle overhead late Thursday night, and a shower is possible, but most areas will likely be dry due to the loss of heating. Expand Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 18z NAM nest has lost the earlier cells for Thursday and instead brings a squall line through parts of the area around 0z. Favors north parts of the area too. Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 I'll be honest - I'm not sure since SARS became publicly visible I've seen so many consistent model runs (even if it's the NAM out in time a bit) - return so many results. I'm used to it showing a bunch of "loose matches" but not many actual results in the boxes. There are a few soundings on the NAM in our area that have so many results they go out of the box for Thursday. Like @high risk has said - I think the main threat is north of the area. This might be a case where north of the Potomac stands the best changes. Will be interesting to watch model trends as we get closer and closer. Risk is there it seems for some big hailers (which except for isolated cases isn't super common around our area). I've seen a few soundings with interesting looking hodos too. Link to comment Share on other sites More sharing options...
high risk Posted May 21, 2019 Share Posted May 21, 2019 On 5/21/2019 at 9:11 PM, Kmlwx said: I'll be honest - I'm not sure since SARS became publicly visible I've seen so many consistent model runs (even if it's the NAM out in time a bit) - return so many results. I'm used to it showing a bunch of "loose matches" but not many actual results in the boxes. There are a few soundings on the NAM in our area that have so many results they go out of the box for Thursday. Like @high risk has said - I think the main threat is north of the area. This might be a case where north of the Potomac stands the best changes. Will be interesting to watch model trends as we get closer and closer. Risk is there it seems for some big hailers (which except for isolated cases isn't super common around our area). I've seen a few soundings with interesting looking hodos too. Expand I like the faster timing of the 18z NAM nest. What I really like is the combination of shear and lapse rates - combinations like these are rare here, and I suspect they're driving the hits with the analogs. Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 On 5/21/2019 at 9:16 PM, high risk said: I like the faster timing of the 18z NAM nest. What I really like is the combination of shear and lapse rates - combinations like these are rare here, and I suspect they're driving the hits with the analogs. Expand Posting the SREF at range below - not for the specific map type - but because it outlines the best risk area really well (and as such the area outlined in SLGT right now for D3). 2 Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 @high risk I suspect if @Eskimo Joe pops in here he might be more enthusiastic than he normally would be. He's generally pretty down on lapse rates in our parts unless we get an EML or something to advect in. Obviously he might find a reason to deb...but he'll be an interesting "weather vane" - let's crack out the WW007 severe weather scale! 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted May 21, 2019 Author Share Posted May 21, 2019 Posted for those who don't want to go digging for it - 3 1 4 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted May 22, 2019 Share Posted May 22, 2019 On 5/21/2019 at 9:19 PM, Kmlwx said: @high risk I suspect if @Eskimo Joe pops in here he might be more enthusiastic than he normally would be. He's generally pretty down on lapse rates in our parts unless we get an EML or something to advect in. Obviously he might find a reason to deb...but he'll be an interesting "weather vane" - let's crack out the WW007 severe weather scale! Expand Looks pretty meh to me, but weather in general is less and less interesting to me with each passing season. We haven't had a good storm since the derecho. 1 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted May 22, 2019 Share Posted May 22, 2019 On 5/19/2019 at 6:49 PM, yoda said: 2 inch hail marker on radarscope and maybe some slight rotation? Expand Saw a report and pics from Clear Spring, MD of 1.75" hail from that cell. This area can get big hailers when there's a good aid to the updraft. Interestingly enough, that was the same cell which got it's act together and dropped an EF-1 tornado in Lancaster County, PA (injuring 3 people). Link to comment Share on other sites More sharing options...
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