OSUmetstud Posted June 6, 2011 Share Posted June 6, 2011 Tuesday night looks tough IMO...the shear is nice...but the low-level warm push is slow. It's going to be tough to crank WAA thunderstorms with 850s of around 12C. Wednesday night is probably more favorable. Link to comment Share on other sites More sharing options...
free_man Posted June 6, 2011 Author Share Posted June 6, 2011 Earlier from SPC VALID 091200Z - 141200Z ...DISCUSSION... NRN-STREAM SHORTWAVE TROUGH AND PRECEDING SFC CYCLONE SHOULD MOVE EWD ACROSS PORTIONS QUE/ONT DAY-4/9TH-10TH...WITH TRAILING COLD FRONT MOVING EWD OVER PORTIONS NY/NEW ENGLAND AND LOWER GREAT LAKES REGION. PROGS AGREE REMARKABLY WELL ON THIS GEN SCENARIO WITH ONLY MINOR TIMING DIFFERENCES. SRN RIM OF HEIGHT FALLS SHOULD CORRESPOND TO THAT OF FAVORABLE DEEP-LAYER DIRECTIONAL SHEAR. MEANWHILE SEASONALLY STG COLD FRONT SHOULD IMPINGE ON RICHLY MOIST BOUNDARY LAYER CONTAINING 60S TO ISOLATED 70S SFC DEW POINTS. SUCH SCENARIO FAVORS CONCENTRATION OF CONVECTIVE WIND POTENTIAL...CURRENTLY MOST PROBABLE OVER NRN NY/NRN NEW ENGLAND CORRIDOR. Something to watch may be Thu nite? if front has the push to make it through C/E New England. There should be plenty of elevated instability to work with. Link to comment Share on other sites More sharing options...
free_man Posted June 6, 2011 Author Share Posted June 6, 2011 I'm starting to like the Wednesday night into early Thursday morning Time frame for storms especially for CNE and NNE. Soundings look pretty great for kcon and kmht at 18z and 21z wednesday just in time for that spill over to occur..we just need that energy to spill over the ridge and Wed be in business.. I'd like to are that ridge relax a bit.. more.north and most severe stays in Maine and Canada Maine looks great for severe right now IMO Let's hope for something like this Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 Lol BIrving.. after that complete miss on 6/1 I think its time we get some SVR in here Link to comment Share on other sites More sharing options...
Typhoon Tip Posted June 6, 2011 Share Posted June 6, 2011 Thursday is interesting.... using the 06z/12z NAM as a kind of synoptic canvas. We have a Sonoran mixed air mass that arrives on a Wednesday behind warm fronal passage; those two days may be very hot, perhaps excessive criteria on Thursday. Cloud may prevent that outright, but +19 to arguable 21C at 850 should hit us into the lower or middle 90s anyway considering it's June; with a fair amount of PGF there will be decent mixing and together with insolation should drive the mercury toward the hottest day thus far regionally. DP will be 65-70+ through out the area, such that combining said temperatures and DP makes the region a powderkeg for convective explosion should even the slightest MLV perturbation take place. Normally I would go with less that ideal helicity, but such intense heat there will undoubtedly come with a lee-side thermal trough from DCA-PWM, along the western side of which there will probably evolve a band of veering wind and thus convergence in the llvs in the static sense - that may be hidden from view at this time. SPC has nadda in the area as of last check. Understandable... we have slight anticyclonic curvature aloft at 18z Thursday in most guidance, with all of 20kts of wind. Link to comment Share on other sites More sharing options...
CoastalWx Posted June 6, 2011 Share Posted June 6, 2011 There is also a possibility that a very weak seabreeze may develop along the mass coast. It's possible that could trigger a few cells, if that does happen. Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 Thursday is interesting.... using the 06z/12z NAM as a kind of synoptic canvas. We have a Sonoran mixed air mass that arrives on a Wednesday behind warm fronal passage; those two days may be very hot, perhaps excessive criteria on Thursday. Cloud may prevent that outright, but +19 to arguable 21C at 850 should hit us into the lower or middle 90s anyway considering it's June; with a fair amount of PGF there will be decent mixing and together with insolation should drive the mercury toward the hottest day thus far regionally. DP will be 65-70+ through out the area, such that combining said temperatures and DP makes the region a powderkeg for convective explosion should even the slightest MLV perturbation take place. Normally I would go with less that ideal helicity, but such intense heat there will undoubtedly come with a lee-side thermal trough from DCA-PWM, along the western side of which there will probably evolve a band of veering wind and thus convergence in the llvs in the static sense - that may be hidden from view at this time. SPC has nadda in the area as of last check. Understandable... we have slight anticyclonic curvature aloft at 18z Thursday in most guidance, with all of 20kts of wind. Could we see that screaming derecho type line of storms like you mentioned yesterday? Something like 1995 or 1999? Link to comment Share on other sites More sharing options...
OSUmetstud Posted June 6, 2011 Share Posted June 6, 2011 Northern New England looks nice on Wednesday as a jet streak puts the in upper level divergence along with some modest 850mb WAA. GFS hints at something with an area of 500mb vorticity just north of NYS on Wednesday. Winds are quite backed at the surface but low-level wind fields are weak. Chance of a tornado or two I suppose. Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 Northern New England looks nice on Wednesday as a jet streak puts the in upper level divergence along with some modest 850mb WAA. GFS hints at something with an area of 500mb vorticity just north of NYS on Wednesday. Winds are quite backed at the surface but low-level wind fields are weak. Chance of a tornado or two I suppose. They really are looking good.. I hope we can get a shift SE for Wednesday... NNE is quietly having a banner year for severe Link to comment Share on other sites More sharing options...
CoastalWx Posted June 6, 2011 Share Posted June 6, 2011 Front drags its feet on Friday over eastern areas. Also looks like some activity comes through Thursday night. Link to comment Share on other sites More sharing options...
OSUmetstud Posted June 6, 2011 Share Posted June 6, 2011 Front drags its feet on Friday over eastern areas. Also looks like some activity comes through Thursday night. Looks like it's increased the 500mb jet a bit....35kt? Not bad I guess. take a look at the 250mb wind field at 06z. Nice divergence lol. Link to comment Share on other sites More sharing options...
bobbutts Posted June 6, 2011 Share Posted June 6, 2011 Massachusetts has a surprisingly high tornado concentration...on par with Ohio? lol I wonder if there just haven't been reported tornadoes yet per state to get a truly accurate representation of tornado concentration. How are the numbers in NJ, RI, and CT? Population Density (as of 2000) http://en.wikipedia.org/wiki/List_of_U.S._states_by_population_density NJ RI MA CT MD DE NY FL PA OH Having lived in FL and driven through OH a few times, I'm sure it's easier to have an unreported tor either places vs. MA. There are vast expanses of open land where a touchdown could occur without bothering anyone or leaving much evidence. In MA there's really nothing like that. Link to comment Share on other sites More sharing options...
CoastalWx Posted June 6, 2011 Share Posted June 6, 2011 Looks like it's increased the 500mb jet a bit....35kt? Not bad I guess. take a look at the 250mb wind field at 06z. Nice divergence lol. Low level winds might be too westerly on Thursday. Usually, not the best for tstms around here. I guess it's still possible some sort of pre-frontal trough could materialize, but I wouldn't be shocked if things get pushed back to Thursday night or Friday. I noticed the euro did try to have some sort of a weak trough come through Thursday, but it looked pretty far east. That, and the fact that the better dynamics are nw of us on Thursday. Still have some time to figure it out, so we'll see as we get closer. Link to comment Share on other sites More sharing options...
Tropopause_Fold Posted June 6, 2011 Share Posted June 6, 2011 NAM has a boat load of instability (elevated in some areas) wed evening on this 12z run. an SI of -7? LOL. Link to comment Share on other sites More sharing options...
OSUmetstud Posted June 6, 2011 Share Posted June 6, 2011 Low level winds might be too westerly on Thursday. Usually, not the best for tstms around here. I guess it's still possible some sort of pre-frontal trough could materialize, but I wouldn't be shocked if things get pushed back to Thursday night or Friday. I noticed the euro did try to have some sort of a weak trough come through Thursday, but it looked pretty far east. That, and the fact that the better dynamics are nw of us on Thursday. Still have some time to figure it out, so we'll see as we get closer. I think the double low solution is mucking up the favorability of low-level winds on Thursday. The first low on Wednesday causes the winds to turn westerly and the second low on Thursday isn't really strong enough to back them ahead of it. Sometimes these MCSs can surprise on the edge of a strong 500mb ridge. Take a look at the dynamics behind July 15, 1995...not really much there. My friend John did his senior seminar on derechoes and that storm somehow propagated forward at 70-90 mph at times with 3000 MLCAPE and only 30-35 kt of deep layer shear without becoming outflow dominant for several hours. Link to comment Share on other sites More sharing options...
ORH_wxman Posted June 6, 2011 Share Posted June 6, 2011 Low level winds might be too westerly on Thursday. Usually, not the best for tstms around here. I guess it's still possible some sort of pre-frontal trough could materialize, but I wouldn't be shocked if things get pushed back to Thursday night or Friday. I noticed the euro did try to have some sort of a weak trough come through Thursday, but it looked pretty far east. That, and the fact that the better dynamics are nw of us on Thursday. Still have some time to figure it out, so we'll see as we get closer. Its kind of looked like that for a few days now. Maybe it will look better as we get closer, but veered winds at the sfc usually aren't good for us as it promotes a downslope/drying type flow. With the airmass that is likely to be in the region, I'm sure we'll get some storms out of it, but I'm not sure they will be all that notable unless we get more backed sfc flow. We could see something nocturnal too. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted June 6, 2011 Share Posted June 6, 2011 Can see a super cell in southern VT running right a tad come later Thursday... SPC has a NW/Central New England 30% outline of probability of severe on that day - btw. Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 Can see a super cell in southern VT running right a tad come later Thursday... SPC has a NW/Central New England 30% outline of probability of severe on that day - btw. Uh-oh wiz just got a woody.. can you provide a link to that website? Edit: Nvm found it.. looks like it run from all of nne to about bennington , kcon, and Portland in a semicircle Link to comment Share on other sites More sharing options...
Typhoon Tip Posted June 6, 2011 Share Posted June 6, 2011 Uh-oh wiz just got a woody.. can you provide a link to that website? Edit: Nvm found it.. looks like it run from all of nne to about bennington , kcon, and Portland in a semicircle Yes. it may also be too early for this level of detail but that kind of hashed out area tends - per my experience - to end up encompassing areas a little further S and E, and that is were discrete cellular activity pops off... The better jet (dynamics in NW NE would cause of line segments that tend to bow). Am aware of the west wind issue mentioned by others however, as I was outlining before (and am less certain of quite frankly) there is a tendency for the winds to back some in lee-side heat troughs, which would enhance helicity along SE VT-W-C Mass and western CT should any discrete cells avail. Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 Yes. it may also be too early for this level of detail but that kind of hashed out area tends - per my experience - to end up encompassing areas a little further S and E, and that is were discrete cellular activity pops off... The better jet (dynamics in NW NE would cause of line segments that tend to bow). Am aware of the west wind issue mentioned by others however, as I was outlining before (and am less certain of quite frankly) there is a tendency for the winds to back some in lee-side heat troughs, which would enhance helicity along SE VT-W-C Mass and western CT should any discrete cells avail. So you think areas just outside of the west winds get hit pretty good, like the outside of that 30% line? Bennington, kcon, and Portland? Link to comment Share on other sites More sharing options...
Typhoon Tip Posted June 6, 2011 Share Posted June 6, 2011 So you think areas just outside of the west winds get hit pretty good, like the outside of that 30% line? Bennington, kcon, and Portland? Areas NW may have more linear activity where the shear is a tad more uni-directional; areas farther S along said axis, may be under a nexus for several hours on Thursday ear marked by high heat/DPs, somewhat more SW wind due to said heat trough causing the llv trajectories to rotate cyclonicall from the high country to the coastal plains, both under transient wind acceleration in the mid levels. It's speculative though... Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 Areas NW may have more linear activity where the shear is a tad more uni-directional; areas farther S along said axis, may be under a nexus for several hours on Thursday ear marked by high heat/DPs, somewhat more SW wind due to said heat trough causing the llv trajectories to rotate cyclonicall from the high country to the coastal plains, both under transient wind acceleration in the mid levels. It's speculative though... I think over the next couple days I'd like to see the ridge relax a bit more to increase our chances for SVR.. I'd love to see 103F but I think 98F would do fine. Also I'd like to try and get into that more linear activity than take a chance on an isolated supercell Link to comment Share on other sites More sharing options...
CoastalWx Posted June 6, 2011 Share Posted June 6, 2011 Euro still keeps things in limbo. Actually brings the front through quicker than the GFS. It does show signs of something perhaps wanting to come through Wednesday night, especially in NNE. Link to comment Share on other sites More sharing options...
OSUmetstud Posted June 6, 2011 Share Posted June 6, 2011 wow Wednesday evening looks pretty interesting on the NAM...nice shear and instability... Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 wow Wednesday evening looks pretty interesting on the NAM...nice shear and instability... Add late Thursday to that list! Link to comment Share on other sites More sharing options...
Typhoon Tip Posted June 6, 2011 Share Posted June 6, 2011 18z NAM has all hell breaking loose in western sections late Thursday afternoon - Link to comment Share on other sites More sharing options...
snowNH Posted June 6, 2011 Share Posted June 6, 2011 18z NAM has all hell breaking loose in western sections late Thursday afternoon - It seems as if the NAM is trending towards a faster frontal passage which allows for the front to hit at a time of maximum instability. Throw that in there with 95-100 degree heat and dews in the 60s/70s. Gonna be a powderkeg like you said Link to comment Share on other sites More sharing options...
CoastalWx Posted June 6, 2011 Share Posted June 6, 2011 NAM is def more ideal as it has more of a pre frontal trough..or perhaps even fropa coming through...tough to tell. Jet dynamics aren't necessarily impressive, but 30kts at 700 and 40kts at 500 isn't too bad. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 6, 2011 Share Posted June 6, 2011 I'll be going chasing up north on Thursday. Looks like a prime setup for a very nasty squall line with potential for some very intense winds and perhaps some large hail. Only issue I'm worried about is how far south the line makes it b/c this is also a setup where these lines can easily outrun the better mid/upper level support as most of the jet energy is actually just behind the actual front. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 6, 2011 Share Posted June 6, 2011 Which areas are you thinking? Upstate NY through northern central VT/NH and parts of ME. Airmass is going to be extremely unstable and wind profile should mainly be unidirectional, not a great deal of shear in place but along/just behind the cold front exist a great deal of shear...so the closer to the front the better. Forecast soundings (at least at BTV) actually have a loaded gun look to them which is pretty damn impressive. Link to comment Share on other sites More sharing options...
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