Kmlwx Posted May 31, 2016 Share Posted May 31, 2016 Perhaps meh severe Friday... then LWX AFD hints at maybe a better threat towards the end of the period Hopefully it doesn't fizzle (probably will) as it gets closer. Not much excitement to talk about around these parts lately. Pretty boring. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 1, 2016 Share Posted June 1, 2016 15% for Sunday. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 1, 2016 Share Posted June 1, 2016 GFS has decent CAPE it seems (nothing extreme, though). Shear looks a bit meh to my eyes Link to comment Share on other sites More sharing options...
high risk Posted June 1, 2016 Share Posted June 1, 2016 Definitely liking the Sunday setup, at least as currently progged: strong cold front arrives during late afternoon with significant height falls and moderate instability. Directional shear is negligible, but the speed shear is strong: 50 kt mid-level jet and 75 kt upper jet, with a 90 kt upper jet core over PA, putting us in the favorable right rear quadrant. Nice setup for a squall line with a fair amount of wind damage. Of course, the details will be resolved, but there is overall model agreement with the arrival of the strong upper trough, so the SPC day 5 outlook makes sense. The timing could get messed up and ruin the setup, but on the other end of the spectrum, if the sfc low ends up deepening more rapidly to our northwest, that in theory could back the low-level flow and introduce some supercell potential. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 1, 2016 Share Posted June 1, 2016 Definitely liking the Sunday setup, at least as currently progged: strong cold front arrives during late afternoon with significant height falls and moderate instability. Directional shear is negligible, but the speed shear is strong: 50 kt mid-level jet and 75 kt upper jet, with a 90 kt upper jet core over PA, putting us in the favorable right rear quadrant. Nice setup for a squall line with a fair amount of wind damage. Of course, the details will be resolved, but there is overall model agreement with the arrival of the strong upper trough, so the SPC day 5 outlook makes sense. The timing could get messed up and ruin the setup, but on the other end of the spectrum, if the sfc low ends up deepening more rapidly to our northwest, that in theory could back the low-level flow and introduce some supercell potential. Drool worthy. Don't get us all excited. If nothing else we can get another test of the system of who gets excited vs how big the event is. Link to comment Share on other sites More sharing options...
yoda Posted June 1, 2016 Share Posted June 1, 2016 12z GFS sounding for KIAD/KDCA for 18z SUN and 21z SUN has around 4000 SBCAPE Link to comment Share on other sites More sharing options...
yoda Posted June 1, 2016 Share Posted June 1, 2016 Link to comment Share on other sites More sharing options...
Kmlwx Posted June 1, 2016 Share Posted June 1, 2016 Only 800+ MLCAPE, though. Still looks pretty robust. Need more backing in the wind field for anything other than a decent line, though (per high risk above). Link to comment Share on other sites More sharing options...
Kmlwx Posted June 1, 2016 Share Posted June 1, 2016 12z CIPS guidance - pretty nice signature for our area. June 1, 2012 has shown up in the analogs for a few runs now. This run it is ranked at #6. That is by far the most robust analog that has been spit out for our area with a few others with iso severe. Have to imagine a 6/1/12 would be about the max potential. Would hedge quite a bit lower at this point. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 1, 2016 Share Posted June 1, 2016 As has been discussed the past several days, severe weather ispossible over parts of the Mid-Atlantic Sunday as wind field increases coincident with adequate instability. Though, run-to-run consistency has made it difficult to delineate the highest threat area. Current indications are that areas along and east of I95 will have the greatest opportunity to recover ahead of cold frontal passage. Fully expect this forecast to change as details become clearer. From the afternoon discussion from LWX. Link to comment Share on other sites More sharing options...
yoda Posted June 2, 2016 Share Posted June 2, 2016 18z GFS sounding at KDCA for 21z SUN: Link to comment Share on other sites More sharing options...
yoda Posted June 2, 2016 Share Posted June 2, 2016 ZCZC SPCSWOD48 ALL ACUS48 KWNS 020901 SPC AC 020901 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0401 AM CDT THU JUN 02 2016 VALID 051200Z - 101200Z ...DISCUSSION... GFS AND ECMWF RUNS FROM 02/00Z CONTINUE TO EXHIBIT FAIRLY GOOD MODEL-TO-MODEL AND RUN-TO-RUN CONSISTENCY...SPECIFICALLY WITH THEIR DEPICTION OF THE EVOLUTION OF A LARGE ERN U.S. STORM SYSTEM. BOTH MODELS ADVANCE A LARGE MID-LEVEL TROUGH EWD ACROSS THE ERN U.S. DAY 4 /SUN. 6-5/...WITH AN ASSOCIATED SURFACE CYCLONE INVOF SRN ONTARIO/LK HURON VICINITY DURING THE AFTERNOON. AS A TRAILING COLD FRONT CROSSES THE APPALACHIANS AND SHIFTS INTO THE E COAST STATES...WIDESPREAD CONVECTION -- LIKELY ALREADY UNDERWAY W OF THE MOUNTAINS ALONG THE FRONT AND FROM THE MID-ATLANTIC REGION NWD IN A WARM ADVECTION ZONE AT THE START OF THE PERIOD -- SHOULD INCREASE STEADILY INTO THE AFTERNOON HOURS. PRESUMING AMPLE DESTABILIZATION CAN OCCUR AHEAD OF THE FRONT /WHICH MAY BE DIFFICULT FROM ROUGHLY ERN PA AND NJ NWD DUE TO MORE PERSISTENT PRECIPITATION AND ASSOCIATED CLOUD COVER/...STORMS SHOULD ORGANIZE LINEARLY AND INTENSIFY WITH TIME -- AIDED BY STRENGTHENING SWLY FLOW THROUGH A DEEP TROPOSPHERIC LAYER AHEAD OF THE UPPER TROUGH. ALONG WITH SOME RISK FOR HAIL...IT APPEARS THAT A FAIRLY WIDESPREAD DAMAGING WIND EVENT MAY EVOLVE ACROSS PORTIONS OF THE MID-ATLANTIC REGION AND SWD INTO NC -- PRESUMING AMPLE HEATING/DESTABILIZATION CAN OCCUR. RISK APPEARS GREAT ENOUGH ATTM TO INTRODUCE 30% RISK AREA ACROSS THIS REGION...WITHIN THE BROADER PRE-FRONTAL SLIGHT RISK ALONG AND E OF THE APPALACHIANS BEING MAINTAINED FROM THE PRIOR OUTLOOK. Link to comment Share on other sites More sharing options...
southmdwatcher Posted June 2, 2016 Share Posted June 2, 2016 ^^^^^^^^^^Yoda^^^^^^^^^^^^^^^^ SPC has now outlooked us for a 30% severe risk on Day 4 Sunday, southeast PA down through eastern NC east of the Blue Ridge. Link to comment Share on other sites More sharing options...
mappy Posted June 2, 2016 Share Posted June 2, 2016 Any idea on timing for Sunday? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
southmdwatcher Posted June 2, 2016 Share Posted June 2, 2016 Sunday could have some morning showers/storms and then clear out and the severe storms would start mid to late afternoon and into the evening. GFS and NAM have 2000-3000+ CAPE and sufficient shear, Sharpy has us in a classic supercell profile region wide through the afternoon and evening. Link to comment Share on other sites More sharing options...
H2O Posted June 2, 2016 Share Posted June 2, 2016 #2016ing. All records will be broken so we will severe Sunday. Link to comment Share on other sites More sharing options...
SmokeEater Posted June 2, 2016 Share Posted June 2, 2016 Almost 4 years to the day, I went down that way and got my first tornado. Maybe again? Don't know how much of a tornado threat there will be this time vs high wind. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 2, 2016 Share Posted June 2, 2016 Many of our high ends days seem to have three common ingredients: 1.) Quick movement into the warm sector, but having the surface warm front nearby. 2.) Good directional shear. 3.) Robust mid level lapse rates. These will be the key factors to look for on Sunday. Obviously #3 is dependent on #1, but the June 2012 event was compensated by the proximity of a strong warm front so we'll see. Link to comment Share on other sites More sharing options...
yoda Posted June 2, 2016 Share Posted June 2, 2016 Afternoon disco from LWX: A strong mid/upper-level trough will pivot towards the areaduring the second half of the weekend. A surge of higher dew pointair in the low-levels will move across the region Sunday afternoonahead of this trough. The overall setup is very similar from modelto model and from run to run, but timing differences remain. Thepotential exists for a substantial severe weather event Sundayafternoon and evening as long as sufficient destabilization canoccur.In favor of severe weather is a strengthening 700-500 mb wind fieldin excess of 50 knots by evening as well as cooler mid-leveltemperatures and an influx of moisture in the low levels. Workingagainst severe weather would be a stronger low level jet andpotential clouds or unfavorable frontal timing (which as mentionedabove is still uncertain). If the front comes through during theevening hours that will allow for maximum heating anddestabilization and thus the greatest risk of severe weather. Thewarm and humid airmass would tend to suggest damaging winds andheavy rain would be the primary threats, though large hail would bepossible with the strongest cells. SPC already has much of the areain a 30% probability for severe weather Sunday despite possiblenegative factors, so no matter how you slice it Sunday looks active.Later trends will have to be watched closely to see if an evenhigher threat develops. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 2, 2016 Share Posted June 2, 2016 Forum was down for me all day until now. Slow loading times and getting the CloudFlare message at times but I'm back. We'll see. Link to comment Share on other sites More sharing options...
southmdwatcher Posted June 2, 2016 Share Posted June 2, 2016 Same for me, one time I did get back into the forum, my security software was blocking one attempted attack after another. Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted June 3, 2016 Share Posted June 3, 2016 I'm going to be out of town Sunday. Well that blows. I'm thinking youll have plenty of other oppurtunities this season though. Link to comment Share on other sites More sharing options...
Amped Posted June 3, 2016 Share Posted June 3, 2016 That's the hope. SPC is bullish on this one. I'm still waiting for Ian to get on board. We may get some severe, there is a 0% chance of the sun coming out for more than 5 minutes in a row like most events in this area. Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted June 3, 2016 Share Posted June 3, 2016 That's the hope. SPC is bullish on this one. I'm still waiting for Ian to get on board. Seems like he might be based on some of his tweets Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted June 3, 2016 Share Posted June 3, 2016 Looks like the NAM may have backed off on the instability a bit to my untrained eye? Link to comment Share on other sites More sharing options...
high risk Posted June 3, 2016 Share Posted June 3, 2016 yes, but because it breaks out a fair amount of precip out ahead of the front throughout the afternoon which eats away at the cape. By early afternoon, the model shows cape in the 1500-2000 range, and one would expect that to go a little higher *if* we continue to heat. Having widespread pre-frontal convection is certainly one of the fail mechanisms for this event, but I think that there is still a good chance that we'll stay dry through the afternoon and fully destabilize. Looks like the NAM may have backed off on the instability a bit to my untrained eye? Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted June 3, 2016 Share Posted June 3, 2016 Most of area in day 3 ENH. ...MID ATLANTIC REGION... AMPLE MOISTURE AND DAYTIME HEATING WILL COUNTERACT RELATIVELY WARM TEMPERATURES ALOFT AND YIELD AROUND ON THE ORDER OF 1500 J/KG MUCAPE ACROSS THE WARM SECTOR BY MID AFTERNOON. WIND SHEAR PROFILES ARE EXPECTED TO STRENGTHEN RAPIDLY DURING THE AFTERNOON AS THE SHORTWAVE TROUGH APPROACHES. MEAN FLOW OF 40-50 KT IN THE 850-500 LAYER WITH INCREASING SPEED SHEAR IN THE UPPER LEVELS WILL RESULT IN LONG HODOGRAPHS FAVORABLE FOR LONG-LIVED SEVERE STORMS INCLUDING A FEW SUPERCELLS. GRADUALLY VEERING 850 MB FLOW AND THE ABSENCE OF A SURGING COLD FRONT SUGGEST SUPERCELLS AS THE DOMINANT STORM MODE DURING THE DAY...WITH PERHAPS MERGING OF CELLS LATER IN THE EVENING AS STORMS EXIT THE COAST. HAIL...DAMAGING WINDS AND A FEW TORNADOES WILL BE POSSIBLE. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted June 3, 2016 Share Posted June 3, 2016 Not every day you see a Day 3 ENH for our area. Sub 1000mb lows don't go quietly into the night. My Spidey sense is tingling. Link to comment Share on other sites More sharing options...
high risk Posted June 3, 2016 Share Posted June 3, 2016 pretty unusual to see SPC discuss supercells as the possible dominant mode in our region. I guess that scenario is plausible if the cold front hangs back, and our initiation is on the lee trough. Link to comment Share on other sites More sharing options...
Kmlwx Posted June 3, 2016 Share Posted June 3, 2016 Wow. Very unusual to see an outlook like that for day 3 here. Now let's shoot for hatching! Can we do it?! Link to comment Share on other sites More sharing options...
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