earthlight Posted April 19, 2011 Share Posted April 19, 2011 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT TUE APR 19 2011 VALID 201200Z - 211200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTHEAST/MID-ATLANTIC STATES... ...SYNOPSIS... THE UPPER TROUGH OVER THE GREAT LAKES EARLY WEDNESDAY WILL CONTINUE TO STEADILY PROGRESS NORTHEASTWARD OVER ONTARIO/QUEBEC AND THE ADJACENT NORTHEAST STATES THROUGH WEDNESDAY NIGHT. WHILE SHORTWAVE RIDGING BEGINS TO OCCUR OVER THE PLAINS...HEIGHT FALLS ARE EXPECTED ACROSS THE WESTERN STATES BY WEDNESDAY NIGHT AS AN UPPER TROUGH BEGINS TO AMPLIFY ALONG THE WEST COAST. ...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...
earthlight Posted April 19, 2011 Author Share Posted April 19, 2011 The SREF continues to flag an area of potential severe weather..lining up well with the SPC slight risk. Link to comment Share on other sites More sharing options...
TheTrials Posted April 19, 2011 Share Posted April 19, 2011 The SREF continues to flag an area of potential severe weather..lining up well with the SPC slight risk. Felt the srefs were too aggresive last week with the failed outbreak. Let's see if they correct themselves. Link to comment Share on other sites More sharing options...
IsentropicLift Posted April 19, 2011 Share Posted April 19, 2011 New Day two risk A 30% risk for this area on a day 2, that's quite rare Link to comment Share on other sites More sharing options...
earthlight Posted April 19, 2011 Author Share Posted April 19, 2011 ...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...
CooL Posted April 19, 2011 Share Posted April 19, 2011 Looks like they cut out my county (bergen county) I would like to see more moisture on the models but its interesting that the spc bumped up the slight risk, and do we get daytime heating tommorrow? could be a fun day Link to comment Share on other sites More sharing options...
TheTrials Posted April 19, 2011 Share Posted April 19, 2011 Like last week, western jersey is the cutoff. Nothing gets into the immediate NYC metro, at least nothing severe. Link to comment Share on other sites More sharing options...
Stormlover74 Posted April 19, 2011 Share Posted April 19, 2011 It seems like one of those typical days when it will be in the 70s in south Jersey and the warm air will take forever to make it north of I-80 and east of the hudson, if at all. Looks like they cut out my county (bergen county) I would like to see more moisture on the models but its interesting that the spc bumped up the slight risk, and do we get daytime heating tommorrow? could be a fun day Link to comment Share on other sites More sharing options...
IsentropicLift Posted April 19, 2011 Share Posted April 19, 2011 Like last week, western jersey is the cutoff. Nothing gets into the immediate NYC metro, at least nothing severe. I see your being more careful with your choice of words today. I should do quite well IMBY. Link to comment Share on other sites More sharing options...
TheTrials Posted April 19, 2011 Share Posted April 19, 2011 I see your being more careful with your choice of words today. I should do quite well IMBY. I said that same thing last week while you calling for tornados. You should be more careful with your words. Link to comment Share on other sites More sharing options...
CooL Posted April 19, 2011 Share Posted April 19, 2011 I said that same thing last week while you calling for tornados. You should be more careful with your words. i dont think there is enough moisture to have anything widespread of extremely heavy. Leaning towards a broken up line and nothing severe up this way. Link to comment Share on other sites More sharing options...
TheTrials Posted April 19, 2011 Share Posted April 19, 2011 i dont think there is enough moisture to have anything widespread of extremely heavy. Leaning towards a broken up line and nothing severe up this way. yip. Link to comment Share on other sites More sharing options...
IsentropicLift Posted April 19, 2011 Share Posted April 19, 2011 If this squall line misses the city to the south, it won't be by much and I simply stated the chance for tornadic activity was not 0%, as per SPC, not that we were going to see a tornadic outbreak. Link to comment Share on other sites More sharing options...
NorEaster27 Posted April 19, 2011 Share Posted April 19, 2011 Upton going with isolated thunder possible: A COLD FRONT THEN APPROACHES WEDNESDAY AFTERNOON WITH CONVECTION FIRING UP AHEAD OF IT. K INDICES TOTAL TOTALS ARE FAVORABLE FOR SOME ISOLATED THUNDER ACROSS THE AREA. Link to comment Share on other sites More sharing options...
Cfa Posted April 19, 2011 Share Posted April 19, 2011 I hate the term "isolated", lol it's another word for "nothing". Link to comment Share on other sites More sharing options...
earthlight Posted April 19, 2011 Author Share Posted April 19, 2011 Link to comment Share on other sites More sharing options...
BlueSkiesFading Posted April 19, 2011 Share Posted April 19, 2011 Earthlight, What do you think of the 2m temps on the 18z NAM for tomorrow? There could be a difference of 20+ degrees over a distance of 20 miles in N and C NJ. Do you think the warm front will get hung up this far south? I haven't seen 2m temps for tomorrow on the Euro or GFS. Are they similar to the NAM, or do they warm sector us? Link to comment Share on other sites More sharing options...
earthlight Posted April 19, 2011 Author Share Posted April 19, 2011 Earthlight, What do you think of the 2m temps on the 18z NAM for tomorrow? There could be a difference of 20+ degrees over a distance of 20 miles in N and C NJ. Do you think the warm front will get hung up this far south? I haven't seen 2m temps for tomorrow on the Euro or GFS. Are they similar to the NAM, or do they warm sector us? The NAM is an outlier with it's extreme cutoff. The Euro has 80 degrees into Western NJ at 18z tomorrow. The SREF has mid 70's. Link to comment Share on other sites More sharing options...
LocoAko Posted April 20, 2011 Share Posted April 20, 2011 Preliminary glance of the 00Z NAM from Twister... CAPE looks to reach 1000-1250 J/kg in Central NJ just south of the front with 60-70kts of Surface-500hPa bulk shear tomorrow afternoon. Lifted Index goes to around -4 and there looks to be some good negative omega at 700hPa. The 4km SPC WRF from 12Z this morning actually brought a cluster/bow echo through central NJ tomorrow but it was a 36-hour forecast, so take it with a grain of salt. Link to comment Share on other sites More sharing options...
LocoAko Posted April 20, 2011 Share Posted April 20, 2011 00Z SPC 4km-WRF says we just get a small cluster of showers tomorrow afternoon. Link to comment Share on other sites More sharing options...
CooL Posted April 20, 2011 Share Posted April 20, 2011 00z spc wrf not enthused with this event at all, it has practically nothing..Dynamics may be solid but we need more juice imo Link to comment Share on other sites More sharing options...
earthlight Posted April 20, 2011 Author Share Posted April 20, 2011 The 00z NAM is warmer throughout...and the 21z SREFs have increased severe probabilities once again. Given the 60+kts of 0-6km vertical shear...juxtaposed with an axis of 1000 j/kg of MLCAPE through 00z...the potential definitely exists for damaging winds within the small warm sector. Specifically in East/Southeast Pennsylvania into Western New Jersey. This potential stretches further south also, towards the M/D line, but the main caveat there would be the weaker forcing for ascent along the wind shift boundary. The main concern (as usual) would definitely be cloud cover in the warm sector. The IR satellite does not look pretty and there is already a ton of convective debris in the Ohio Valley. This concern is only made greater by the potential for the surface warm front to get hung up over New Jersey as indicated by some of the higher resolution models. Although the temperatures may eventually increase with the wind shift, the clouds taking longer to exit the warm sector could be a serious inhibitor to rooted convection developing. In a sense, if we don't get the adequate surface heating..the instability will not be there..and the result would likely be an area of weaker convection developing along the wind shift and moving rapidly northeast through PA and NJ with some heavier rain and a few rumbles of thunder. That being said...the shortwave is very well oriented for convection to develop around 18z tomorrow. This is not an eye-opening setup, but it's certainly one that can produce more than a few reports of severe wind gusts if all goes right, and stronger updrafts can develop within the unstable and favorable thermodynamic environment..that will have kinematic support. We will see tomorrow morning. Link to comment Share on other sites More sharing options...
nzucker Posted April 20, 2011 Share Posted April 20, 2011 Looks as if the low tracks a bit too close to us for ideal severe...considering the cloud cover that system will induce and the lingering clouds from today's weak wave, it may be hard to get the diurnal heating in there. 45.2/42 Link to comment Share on other sites More sharing options...
TheTrials Posted April 20, 2011 Share Posted April 20, 2011 Beautiful squall line going through upstate ny right now, probably the only action even close to the area today. Very low probability threat from the start IMHO. Link to comment Share on other sites More sharing options...
IsentropicLift Posted April 20, 2011 Share Posted April 20, 2011 Updated SPC convective outlook, now slight risks entire NY metro Link to comment Share on other sites More sharing options...
IsentropicLift Posted April 20, 2011 Share Posted April 20, 2011 Beautiful squall line going through upstate ny right now, probably the only action even close to the area today. Very low probability threat from the start IMHO. That line is decaying quickly as it pushes east Link to comment Share on other sites More sharing options...
6zNam Posted April 20, 2011 Share Posted April 20, 2011 Beautiful squall line going through upstate ny right now, probably the only action even close to the area today. Very low probability threat from the start IMHO. Why? Link to comment Share on other sites More sharing options...
IsentropicLift Posted April 20, 2011 Share Posted April 20, 2011 Why? He's been downplaying all the severe chances so far this year for one reason or another. Either way, I think I'll stick with SPC on this one. Link to comment Share on other sites More sharing options...
TheTrials Posted April 20, 2011 Share Posted April 20, 2011 He's been downplaying all the severe chances so far this year for one reason or another. Either way, I think I'll stick with SPC on this one. So far the setups (all two of them,lol) have been far less than ideal. Last weeks had no trigger mechanism, today will be similar and also don't think we see the instability, especially NYC on east. Far western jersey, sw jersey into PA a different story and a different forecast area. Link to comment Share on other sites More sharing options...
earthlight Posted April 20, 2011 Author Share Posted April 20, 2011 So far the setups (all two of them,lol) have been far less than ideal. Last weeks had no trigger mechanism, today will be similar and also don't think we see the instability, especially NYC on east. Far western jersey, sw jersey into PA a different story and a different forecast area. I think the cloud debris will act as an inhibitor to the surface destabilization a good bit---but that doesn't mean that you can say the severe chances were low from the get go. That's the part of your post that I don't agree with at all. This is a solid setup thermodynamically and kinematically...there is a reason why, even despite the clouds, SPC is maintaining a Slight Risk of severe thunderstorms. Given the clouds in the warm sector..the threat is definitely less. But there is certainly a trigger mechanism with a strong shortwave over Central PA at 18z, there is certainly enough instability even into Northeast NJ with 1000 j/kg of MUCAPE at 12z on all guidance..and there is certainly the potential for organized convection with 60+kts of 0-6km bulk shear. Link to comment Share on other sites More sharing options...
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