weatherwiz Posted June 17, 2013 Share Posted June 17, 2013 One thing computer models really underplayed was how quickly we were able to clear out. We cleared out as early as 10-11 PM last night and are basking in full sunshine right now. This should allow us to generate some modest instability this afternoon. However, like many setups there are flags here. 1) Evident on forecast soundings, there are some funky warm layers between 700mb and 500mb and these funky warm layers may really be a negative for generating strong/robust updrafts, despite stronger instability/shear. 2) While shear is quite strong aloft, evident by the 35-45 knots of vertical shear in place, the cold front is not very strong in nature and the s/w energy moving through southern Quebec is not very strong either, so we aren't looking at a tremendous amount of forcing/lift from the front itself. However, the region is in the RFQ of a very strong ULJ which could compensate. 3) While dewpoints are closer to those progged by the NAM, given how dewpoints at 925/850 are <10C, strong heating and mixing may allow for dewpoints to mix down at the surface some, however, if we can get some higher theta-e air into the region, we may be able to pool dewpoints some, allowing for dewpoints to remain consistent or even perhaps increase...this is something to watch for tomorrow! Given the parameters we are dealing with we certainly have to watch out for some stronger convection today, perhaps even turning severe. Damaging winds certainly are the main severe threat but hail can't be ruled out either, especially in stronger corers...have to also watch for some weakly rotating storms or even brief supercells, enhancing the hail possibility. Flash flooding will also be a concern, given higher PWAT air advecting into the region. Link to comment Share on other sites More sharing options...
CT Rain Posted June 17, 2013 Share Posted June 17, 2013 Somewhat conflicting signals but there are a few things in place that could lead to some decent storms around the region. Well timed short wave (around 21Z) with nice jet dynamics and very strong deep layer shear (approaching 50 knots). How much boundary layer moisture mixes out will determine whether or not we'll have enough instability to play later. There are some higher dews back across SE PA and NJ that may try to advect north into southern areas after things mix out a bit. Not a slam dunk today but there is the risk for hail and gusty winds and maybe even an isolated spinner along the stalled boundary. Link to comment Share on other sites More sharing options...
Brian5671 Posted June 17, 2013 Share Posted June 17, 2013 would this be a line sweeping through or more of a discrete supercell type setup? Link to comment Share on other sites More sharing options...
radarman Posted June 17, 2013 Share Posted June 17, 2013 One thing computer models really underplayed was how quickly we were able to clear out. We cleared out as early as 10-11 PM last night and are basking in full sunshine right now. This should allow us to generate some modest instability this afternoon. However, like many setups there are flags here. 1) Evident on forecast soundings, there are some funky warm layers between 700mb and 500mb and these funky warm layers may really be a negative for generating strong/robust updrafts, despite stronger instability/shear. 2) While shear is quite strong aloft, evident by the 35-45 knots of vertical shear in place, the cold front is not very strong in nature and the s/w energy moving through southern Quebec is not very strong either, so we aren't looking at a tremendous amount of forcing/lift from the front itself. However, the region is in the RFQ of a very strong ULJ which could compensate. 3) While dewpoints are closer to those progged by the NAM, given how dewpoints at 925/850 are <10C, strong heating and mixing may allow for dewpoints to mix down at the surface some, however, if we can get some higher theta-e air into the region, we may be able to pool dewpoints some, allowing for dewpoints to remain consistent or even perhaps increase...this is something to watch for tomorrow! Given the parameters we are dealing with we certainly have to watch out for some stronger convection today, perhaps even turning severe. Damaging winds certainly are the main severe threat but hail can't be ruled out either, especially in stronger corers...have to also watch for some weakly rotating storms or even brief supercells, enhancing the hail possibility. Flash flooding will also be a concern, given higher PWAT air advecting into the region. Nice job. I'm encouraged that the surface winds here have been out of the S and the DPs have been steady. I agree the main threat is wind today given the unidirectional flow aloft. Also, I could see the line being broken up some along the front, not solid which could allow for individual cells to take on supercell characteristics, in which case there could be some hail and locally enhanced helicity. Link to comment Share on other sites More sharing options...
CT Rain Posted June 17, 2013 Share Posted June 17, 2013 Guess it wasn't good enough Oops... my bad... I didn't even see it! I'll merge mine into yours. Link to comment Share on other sites More sharing options...
CT Rain Posted June 17, 2013 Share Posted June 17, 2013 would this be a line sweeping through or more of a discrete supercell type setup? Probably some multi cell clusters and possibly some supercells. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Oops... my bad... I didn't even see it! I'll merge mine into yours. No biggie Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Nice job. I'm encouraged that the surface winds here have been out of the S and the DPs have been steady. I agree the main threat is wind today given the unidirectional flow aloft. Also, I could see the line being broken up some along the front, not solid which could allow for individual cells to take on supercell characteristics, in which case there could be some hail and locally enhanced helicity. Thanks. Certainly interesting. Appear to be several mesoscale boundaries around as well. Don't think we'll see much of tornado potential given high LCL's and unidirectional flow...but some supercells (if we see some) could get a tad interesting. I'm thinking hail may end up being a bit more of a hazard than being thought, especially if we see more in the way of discrete, which is a possibility. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Looks like an upgrade to slight along with possibility of a watch MESOSCALE DISCUSSION 1106NWS STORM PREDICTION CENTER NORMAN OK1107 AM CDT MON JUN 17 2013AREAS AFFECTED...CENTRAL NY INTO WRN PARTS OF NEW ENGLANDCONCERNING...SEVERE POTENTIAL...WATCH POSSIBLEVALID 171607Z - 171730ZPROBABILITY OF WATCH ISSUANCE...40 PERCENTSUMMARY...SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THISAFTERNOON IN PRE-FRONTAL WARM SECTOR. THE COMBINATION OFWEAK-MODERATE INSTABILITY AND SUBSTANTIAL DEEP-LAYER SHEAR WILLSUPPORT ORGANIZED STORMS WITH SOME RISK FOR DAMAGING GUSTS ANDMARGINALLY SEVERE HAIL. THE MAGNITUDE OF THE RISK AND THE NEED FORA WATCH ARE STILL IN QUESTION...BUT A PORTION OF THIS AREA WILL BEUPGRADED TO SLIGHT RISK AT 1630Z.DISCUSSION...VISIBLE SATELLITE IMAGERY SHOWS AN AREA OF DEVELOPINGBOUNDARY LAYER CUMULUS ACROSS CENTRAL NY...SE OF THE A DIFFUSESURFACE COLD FRONT INVOF THE SAINT LAWRENCE VALLEY. AS SURFACETEMPERATURES WARM INTO THE UPPER 70S...MLCAPE WILL REACH 1000-1500J/KG WITH SOME VERTICAL MIXING OF LOW-LEVEL MOISTURE. EXPECT WIDELYSCATTERED THUNDERSTORM DEVELOPMENT WITHIN THE NEXT COUPLE OFHOURS...AND STORMS WILL SPREAD EWD THROUGH THE EARLY-MID AFTERNOON.THIS AREA IS ALONG THE SRN FRINGE OF THE STRONGER MIDLEVELWLYS...WHICH ARE CONTRIBUTING TO EFFECTIVE BULK SHEAR AOA 40 KT ANDLONG STRAIGHT HODOGRAPHS. THE NET RESULT SHOULD BE A FEWORGANIZED/SUPERCELL TYPE STORMS CAPABLE OF PRODUCING AT LEASTISOLATED DAMAGING GUSTS GIVEN THE STRONG DEEP-LAYER SHEAR ANDSTEEPENING LOW-LEVEL LAPSE RATES. THOUGH LAPSE RATES ALOFT ARE NOTPARTICULARLY STEEP...COOL MIDLEVEL TEMPERATURES AND POTENTIALLYMODERATE BUOYANCY COULD SUPPORT MARGINALLY SEVERE HAIL WITH THESTRONGEST STORMS...THOMPSON/GUYER.. 06/17/2013 Link to comment Share on other sites More sharing options...
Damage In Tolland Posted June 17, 2013 Share Posted June 17, 2013 @NWSSPC: #SPC_MD 1106 affecting CENTRAL NY INTO WRN PARTS OF NEW ENGLAND, #mawx #nhwx #vtwx #ctwx #nywx, http://t.co/BwhWfXy2rk Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Stuff really beginning to go up in NYS Link to comment Share on other sites More sharing options...
Damage In Tolland Posted June 17, 2013 Share Posted June 17, 2013 Wizzy, what timing you got for this in NE CT? Link to comment Share on other sites More sharing options...
CoastalWx Posted June 17, 2013 Share Posted June 17, 2013 HRRR brings a nice line in later today. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Wizzy, what timing you got for this in NE CT? After 6 PM or so. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 We have a pocket of some crappy lapse rates over us now and dews did drop a few degrees...so this combination is leading to some meh MLcape values and LI values. See if these can rebound later on, which some models are hinting at. Link to comment Share on other sites More sharing options...
CT Rain Posted June 17, 2013 Share Posted June 17, 2013 Dew points continue to mix out. Will have to see if the models are right by bringing them back up later this afternoon. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Dew points continue to mix out. Will have to see if the models are right by bringing them back up later this afternoon. Good thing our timeframe is much later on so we'll have that chance to bring them back up. Link to comment Share on other sites More sharing options...
forkyfork Posted June 17, 2013 Share Posted June 17, 2013 i'm surprised the slight risk doesn't extend further SW Link to comment Share on other sites More sharing options...
Damage In Tolland Posted June 17, 2013 Share Posted June 17, 2013 Dews always seem to come back up in the late afternoon in summer as winds die down and flow turns south in evening many times Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 SVR warned cell heading near Utica has some rotation along with a hook like feature Link to comment Share on other sites More sharing options...
CoastalWx Posted June 17, 2013 Share Posted June 17, 2013 MLCAPE should....should go up I think right before the front as dewpoints in the lower few thousand feet climb a bit. Kind of a battle though, but luckily temps aloft are rather cool. I like the 50kt+ winds at 500mb. That should help congeal a line like we are seeing in NY state. Just a matter of what happens here. I noticed some mesos like the SPC WRF almost have two lines. The earlier line looks a little suspicious to me. Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 dews still mid 60's s CT Link to comment Share on other sites More sharing options...
free_man Posted June 17, 2013 Share Posted June 17, 2013 Is that a developing supercell near the MA/VT border? Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Is that a developing supercell near the MA/VT border? That has had major trouble developing since it's development. On ENX, it's barely even to 20K for the tops and very little dbz up past 10K. Link to comment Share on other sites More sharing options...
Ginx snewx Posted June 17, 2013 Share Posted June 17, 2013 Meh Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 Watch out Link to comment Share on other sites More sharing options...
Modfan Posted June 17, 2013 Share Posted June 17, 2013 Watch out For? Link to comment Share on other sites More sharing options...
dryslot Posted June 17, 2013 Share Posted June 17, 2013 Marginal up here Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 17, 2013 Share Posted June 17, 2013 WOUS64 KWNS 171712 WOU1 BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH OUTLINE UPDATE FOR WS 321 NWS STORM PREDICTION CENTER NORMAN OK 115 PM EDT MON JUN 17 2013 SEVERE THUNDERSTORM WATCH 321 IS IN EFFECT UNTIL 900 PM EDT FOR THE FOLLOWING LOCATIONS CTC001-003-005-007-009-011-013-015-180100- /O.NEW.KWNS.SV.A.0321.130617T1715Z-130618T0100Z/ CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD HARTFORD LITCHFIELD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MAC003-005-009-011-013-015-017-021-023-025-027-180100- /O.NEW.KWNS.SV.A.0321.130617T1715Z-130618T0100Z/ MA . MASSACHUSETTS COUNTIES INCLUDED ARE BERKSHIRE BRISTOL ESSEX FRANKLIN HAMPDEN HAMPSHIRE MIDDLESEX NORFOLK PLYMOUTH SUFFOLK WORCESTER NHC005-011-013-015-019-180100- /O.NEW.KWNS.SV.A.0321.130617T1715Z-130618T0100Z/ NH . NEW HAMPSHIRE COUNTIES INCLUDED ARE CHESHIRE HILLSBOROUGH MERRIMACK ROCKINGHAM SULLIVAN NYC001-007-017-021-025-027-035-039-041-043-053-057-065-071-077- 079-083-087-091-093-095-105-111-113-115-119-180100- /O.NEW.KWNS.SV.A.0321.130617T1715Z-130618T0100Z/ NY . NEW YORK COUNTIES INCLUDED ARE ALBANY BROOME CHENANGO COLUMBIA DELAWARE DUTCHESS FULTON GREENE HAMILTON HERKIMER MADISON MONTGOMERY ONEIDA ORANGE OTSEGO PUTNAM RENSSELAER ROCKLAND SARATOGA SCHENECTADY SCHOHARIE SULLIVAN ULSTER WARREN WASHINGTON WESTCHESTER RIC001-003-005-007-009-180100- /O.NEW.KWNS.SV.A.0321.130617T1715Z-130618T0100Z/ RI . RHODE ISLAND COUNTIES INCLUDED ARE BRISTOL KENT NEWPORT PROVIDENCE WASHINGTON VTC003-025-180100- /O.NEW.KWNS.SV.A.0321.130617T1715Z-130618T0100Z/ VT . VERMONT COUNTIES INCLUDED ARE BENNINGTON WINDHAM ANZ230-236-237-250-251-180100- /O.NEW.KWNS.SV.A.0321.130617T1715Z-130618T0100Z/ CW . ADJACENT COASTAL WATERS INCLUDED ARE BOSTON HARBOR NARRAGANSETT BAY BLOCK ISLAND SOUND COASTAL WATERS EAST OF IPSWICH BAY AND THE STELLWAGEN BANK NATIONAL MARINE SANCTUARY MASSACHUSETTS BAY AND IPSWICH BAY ATTN...WFO...OKX...BOX...ALY...BGM...GYX... Link to comment Share on other sites More sharing options...
weatherwiz Posted June 17, 2013 Author Share Posted June 17, 2013 For? All of CT, all of MA except Barnstable, southern NH/southern VT and eastern NY Link to comment Share on other sites More sharing options...
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