Thunder Road Posted April 19, 2011 Share Posted April 19, 2011 0z NAM looks like a decent hit of thunderstorms. We get much farther into the warm sector than the 18z GFS. Not sure of cloud cover, but we're at least dry at 12z and 18z, which is more than the GFS offers. Given the NAM's better performance Saturday night, and that storm's northward trend, right now I'm liking the chances for some severe weather Wednesday evening in most areas north, west, south and east of Brookhaven. Let's see what pans out... Link to comment Share on other sites More sharing options...
Thunder Road Posted April 19, 2011 Author Share Posted April 19, 2011 NAM sim radar tries to get a line segment going at 18z, then collapses it again... Maybe there are discrete storms it's not picking up though, as there is light precip over the PHL metro between 42 and 48. Link to comment Share on other sites More sharing options...
LMolineuxLM1 Posted April 19, 2011 Share Posted April 19, 2011 Hey FWIW i have off thursday so if it takes me to have a drive wednesday night i will take it. Link to comment Share on other sites More sharing options...
NaoPos Posted April 19, 2011 Share Posted April 19, 2011 from today's SPC day 3 outlook: ...NORTHEAST/MID ATLANTIC STATES TO CENTRAL/SOUTHERN APPALACHIANS AND TN VALLEY/SOUTHEAST STATES... AN EARLY DAY ISOLATED SEVERE THREAT /MAINLY DAMAGING WINDS/ COULD STILL BE ONGOING EARLY WEDNESDAY ACROSS PORTIONS OF THE UPPER OH/TN RIVER VALLEYS TOWARD THE SPINE OF THE APPALACHIANS. THE EXTENSIVENESS/TIMING OF SUCH CONVECTION ALONG/AHEAD OF THE EASTWARD ADVANCING COLD FRONT PROVIDES UNCERTAINTY REGARDING THE LIKELIHOOD/COVERAGE OF A SEVERE THREAT INTO WEDNESDAY. NONETHELESS...A SEVERE THREAT COULD REDEVELOP/INCREASE BY WEDNESDAY AFTERNOON TOWARD/EAST OF THE APPALACHIANS INTO THE NORTHEAST STATES/PERHAPS MID-ATLANTIC REGION ALONG/AHEAD OF THE COLD FRONT...WITH DAMAGING WINDS AS THE PRIMARY CONCERN. WHILE UNCERTAINTY EXISTS REGARDING THE DEGREE OF DESTABILIZATION COLOCATED WITH THE BRUNT OF LARGE SCALE FORCING/UPPER JET...IT IS POSSIBLE THAT PORTIONS OF THE NORTHEAST STATES MAY WARRANT A SLIGHT RISK IN SUBSEQUENT OUTLOOKS. FARTHER SOUTHWEST ALONG THE SOUTHEAST ADVANCING COLD FRONT INTO THE SOUTHERN APPALACHIANS/TN VALLEY/SOUTHEAST STATES...LARGE SCALE FORCING IS EXPECTED TO BE CONSIDERABLY MORE LIMITED WITH WEAKENING MASS CONVERGENCE DURING THE DAY. HOWEVER...THE ADVANCING COLD FRONT/PERHAPS REMNANT COLD POOLS COULD FOCUS ADDITIONAL STRONG/SEVERE TSTM DEVELOPMENT DURING THE DAY...AT LEAST IN AN ISOLATED/EPISODIC SENSE. http://www.spc.noaa.gov/products/outlook/day3otlk.html Link to comment Share on other sites More sharing options...
Thunder Road Posted April 19, 2011 Author Share Posted April 19, 2011 SPC's Day 2 puts us all in a SLIGHT... ...NORTHEAST/MID-ATLANTIC STATES TO CENTRAL/SOUTHERN APPALACHIANS AND TN VALLEY/SOUTHEAST STATES... SOME EARLY DAY SEVERE THREAT COULD STILL BE ONGOING WEDNESDAY MORNING ACROSS PORTIONS OF THE UPPER OH/TN RIVER VALLEYS TOWARD THE SPINE OF THE APPALACHIANS...MAINLY IN THE FORM OF DAMAGING WINDS. BY WEDNESDAY AFTERNOON...IT IS PROBABLE THAT A RENEWED UPSWING OF CONVECTIVE COVERAGE/VIGOR WILL OCCUR...PERHAPS MOST CERTAIN ACROSS THE SOUTHERN APPALACHIANS AND TN VALLEY TO GULF COAST STATES EVEN IN THE PRESENCE OF MODEST LARGE SCALE FORCING FOR ASCENT. THE EAST-SOUTHEASTWARD ADVANCING COLD FRONT...AND/OR REMNANT COLD POOLS FROM TUESDAY NIGHTS CONVECTION...WILL HELP FOCUS ADDITIONAL TSTM DEVELOPMENT WITHIN AN UNSTABLE AIRMASS FROM PORTIONS OF THE GULF COAST STATES/SOUTHERN APPALACHIANS VICINITY INTO THE MID-ATLANTIC STATES. OVERALL...DAMAGING WINDS ARE EXPECTED TO BE THE PRIMARY CONCERN. ANY SEVERE THREAT SHOULD GENERALLY WANE EARLY WEDNESDAY EVENING. Link to comment Share on other sites More sharing options...
JCT777 Posted April 19, 2011 Share Posted April 19, 2011 Looks like high temps in the low 80's tomorrow in the Philly area. Link to comment Share on other sites More sharing options...
SmokeEater Posted April 19, 2011 Share Posted April 19, 2011 New outlook brings 30% probs for us. DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1147 AM CDT TUE APR 19 2011 VALID 201200Z - 211200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MIDDLE ATLANTIC... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN APPALACHIANS TO SCNTRL TX... ...MIDDLE ATLANTIC... MODEST MID LEVEL HEIGHT FALLS WILL OVERSPREAD THE OH VALLEY INTO THE DAY2 PERIOD...GLANCING THE DELMARVA REGION DURING THE AFTERNOON HOURS IN CONJUNCTION WITH EXPECTED FRONTAL PASSAGE. ALTHOUGH THE PRIMARY FORCING ASSOCIATED WITH THE STRONG SPEED MAX/SHORTWAVE TROUGH WILL AFFECT THE GREAT LAKES INTO THE SERN PROVINCES OF ONTARIO/QUEBEC...IT APPEARS SUFFICIENT FORCING WILL BE NOTED ALONG AN ADVANCING COLD FRONT SUCH THAT ROBUST CONVECTION IS EXPECTED TO REDEVELOP/INTENSIFY ALONG WIND SHIFT PRIMARILY AFTER 18Z. LATEST MODEL GUIDANCE AND FORECAST SOUNDINGS SUGGEST THE WARM SECTOR ACROSS PA INTO THE DELMARVA WILL EXPERIENCE SUBSTANTIAL SFC HEATING...MORE THAN ADEQUATE FOR TSTM INITIATION GIVEN THE EXPECTED FRONTAL CONVERGENCE AND AFTERNOON TEMPERATURES INTO THE MID 70S. DEEPENING WLY FLOW WITH SBCAPE ON THE ORDER OF 1000+ J/KG SHOULD PROVE FAVORABLE FOR DAMAGING WIND GUSTS WITH THE STRONGEST FRONTAL CONVECTION. Link to comment Share on other sites More sharing options...
NaoPos Posted April 19, 2011 Share Posted April 19, 2011 just some paremters from the 12z NAM for 18z tomorrow: Link to comment Share on other sites More sharing options...
Thunder Road Posted April 19, 2011 Author Share Posted April 19, 2011 12z SPC WRF says "Hello, Lee!" Link to comment Share on other sites More sharing options...
NaoPos Posted April 19, 2011 Share Posted April 19, 2011 That's sexy^^^ Link to comment Share on other sites More sharing options...
NJHurricane Posted April 20, 2011 Share Posted April 20, 2011 Sounds like, as usual, chances that storms will achieve severe parameters will depend on how quickly or if we get a decent period of sun after the warm front lifts through before the arrival of the main squall line(s). Link to comment Share on other sites More sharing options...
Thunder Road Posted April 20, 2011 Author Share Posted April 20, 2011 Sounds like, as usual, chances that storms will achieve severe parameters will depend on how quickly or if we get a decent period of sun after the warm front lifts through before the arrival of the main squall line(s). I think we'll warm/destabilize enough just from being in the warm sector. Sunshine can't hurt, of course, but I wouldn't say we're dependent on it. Link to comment Share on other sites More sharing options...
Thunder Road Posted April 20, 2011 Author Share Posted April 20, 2011 new SPC WRF is significantly less sexy than 12z. Hard to tell what the problem is when we can't see its parameters like instability, DPs, capping... Link to comment Share on other sites More sharing options...
earthlight Posted April 20, 2011 Share Posted April 20, 2011 new SPC WRF is significantly less sexy than 12z. Hard to tell what the problem is when we can't see its parameters like instability, DPs, capping... Likely clouds within the warm sector as it seems to be an outlier right now with it's extremely sharp 2m temperature cutoff. Even the NAM, which was cooler, trended warmer on tonights 00z runs. But to answer your question...it's likely a combination of the surface warm front getting caught up, keeping clouds and cooler temperatures around...resulting in a lack of thermodynamic support. Further south..where it's warmer..it's likely keying in on less favorable forcing for ascent, hence the non-development of updrafts. I really wish they produced sb/mu cape or even cloud cover maps for the spc wrf...but for now all we can do is take an educated guess. Link to comment Share on other sites More sharing options...
NaoPos Posted April 20, 2011 Share Posted April 20, 2011 Back down to a 15% slight risk. Would post images, but going on my iPhone. Same areas as yesterday's slight risk Link to comment Share on other sites More sharing options...
Big Jims Videos Posted April 20, 2011 Share Posted April 20, 2011 warm front is gonna have a helluva time clearing central/NEPA. Link to comment Share on other sites More sharing options...
Riptide Posted April 20, 2011 Share Posted April 20, 2011 The warm front is just now passing through my area. Definitely not the most promising setup with upper-air support displaced far away from the warm sector. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted April 20, 2011 Share Posted April 20, 2011 warm front is gonna have a helluva time clearing central/NEPA. That's my biggest fear, WF doesn't get here and we get stuck ~50 with the same old cloudy crap. Link to comment Share on other sites More sharing options...
NJHurricane Posted April 20, 2011 Share Posted April 20, 2011 looks like a fair amount of clearing over southern 3/4 of Delmarva and sw surface flow has brought surging temps and dwpts there...per vis clearing area trying to push up through south Jersey now, cloud cover holding tough back towards philly and the lower delaware river so far. Link to comment Share on other sites More sharing options...
Big Jims Videos Posted April 20, 2011 Share Posted April 20, 2011 That's my biggest fear, WF doesn't get here and we get stuck ~50 with the same old cloudy crap. 53 here cloudy foggy and damp and cool and stuck in horrible i-81 traffic. there won't be any severe here. Link to comment Share on other sites More sharing options...
NJHurricane Posted April 20, 2011 Share Posted April 20, 2011 53 here cloudy foggy and damp and cool and stuck in horrible i-81 traffic. there won't be any severe here. does the WRF incorporate traffic data? Sun starting to break out here in Woodbury NJ (SSE of PHL) now...will be interesting to see if SPC goes a little more optimistic later for areas that manage to get into decent sun before noon. I think just south of here has a fighting chance at scattered severe. Link to comment Share on other sites More sharing options...
IsentropicLift Posted April 20, 2011 Share Posted April 20, 2011 Surface based CAPE surging northward as the warm front pushes northward. Mid-level lapse rates are also very strong. Link to comment Share on other sites More sharing options...
NaoPos Posted April 20, 2011 Share Posted April 20, 2011 Sun's out here in Secane/Upper Darby Link to comment Share on other sites More sharing options...
LMolineuxLM1 Posted April 20, 2011 Share Posted April 20, 2011 Sun's out here in Secane/Upper Darby Sun is out and been out for about 35 to 40 mins now here in Ardmore Link to comment Share on other sites More sharing options...
Big Jims Videos Posted April 20, 2011 Share Posted April 20, 2011 clearing starting to take place in hazleton after we busted through traffic jam due to UPS truck flipped over at AVP exit. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted April 20, 2011 Share Posted April 20, 2011 What is that bright light from the sky...?? Link to comment Share on other sites More sharing options...
NJHurricane Posted April 20, 2011 Share Posted April 20, 2011 temp surge for areas that have gotten into sw flow...millville, ac, dover in mid 70's...wilmington and PHL still in upper 50's Link to comment Share on other sites More sharing options...
LMolineuxLM1 Posted April 20, 2011 Share Posted April 20, 2011 temp surge for areas that have gotten into sw flow...millville, ac, dover in mid 70's...wilmington and PHL still in upper 50's 79 at Dover but in the 50's here in se pa. Link to comment Share on other sites More sharing options...
DerekZ Posted April 20, 2011 Share Posted April 20, 2011 1630z SPC Outlook keeps E PA and northern half of NJ in Slight Risk. Areas further south have been dropped. 15% for wind and 2% for tornadoes. NORTHEAST/MID ATLANTIC... SHORTWAVE TROUGH AND ASSOCIATED CORRIDOR OF 12-HR HEIGHT FALLS EXCEEDING 100-150 M AT 500 MB WILL TRANSLATE FROM THE GREAT LAKES AND OH VALLEY NEWD THROUGH NEW ENGLAND AND THE ST. LAWRENCE VALLEY TODAY. ASSOCIATED SURFACE LOW OVER SWRN ONTARIO AS OF 16Z WILL CONCURRENTLY DEVELOP NEWD INTO FAR SRN QUEBEC BY 21/00Z WITH TRAILING COLD FRONT MOVING INTO THE HUDSON AND DE RIVER VALLEYS BY THIS TIME. WARM FRONT IS EXPECTED TO LIFT NWD THROUGH AT LEAST THE LOWER HUDSON VALLEY BY LATE AFTERNOON/EARLY EVENING. MORNING VISIBLE SATELLITE IMAGERY INDICATES BREAKS IN THE CLOUDS AHEAD OF THE COLD FRONT ACROSS NY/PA WHICH SHOULD ALLOW FOR STRONGER DIABATIC HEATING. WHEN COUPLED WITH BOUNDARY LAYER DEWPOINTS IN THE 50S...EXPECT AFTERNOON MLCAPE OF 500-1000 J/KG. LATEST MESOSCALE AND CONVECTION-ALLOWING MODEL GUIDANCE SUGGEST THAT WEAK CONVERGENCE ALONG THE COLD FRONT MAY LIMIT STORM COVERAGE THIS AFTERNOON INTO EVENING. GIVEN THE STRONG WLY WIND FIELD IN PLACE...ANY STORMS THAT CAN DEVELOP WILL BE CAPABLE OF DAMAGING WIND GUSTS AND PERHAPS A BRIEF TORNADO. Link to comment Share on other sites More sharing options...
Thunder Road Posted April 20, 2011 Author Share Posted April 20, 2011 14z HRRR says we get into some storm action as early as 20z already. Not very discrete though, and therefore not too strong... Link to comment Share on other sites More sharing options...
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