weatherwiz Posted April 29, 2014 Share Posted April 29, 2014 Looks like our unofficial official start to severe weather season starts off appropriately on Thursday, May 1st as we will have the potential for some thunderstorms. While the entire region may have the potential, the higher likelihood may be confined to areas south of the MA Pike and perhaps moreso across the south coast and especially southeastern MA. A very slow moving area of low pressure off to our west will push a warm front northward. Typically in these setups the models can be too aggressive with how far north the warm front gets so it isn't clear cut as to how far north the warm front will get. Regardless, south of where the warm front resides, dewpoints should climb close to or perhaps a few ticks above the 60F mark. This will be fueled by a pretty steep increase in theta-e values. While widespread cloudiness should prevail, there are some hints that some breaks of sun may occur, this will help to drive temperatures perhaps into the upper 60's to near 70F, especially south of the warm front where a warmer llvl airmass will reside. Meanwhile, a cold front will be approaching from the west and will work to increase lift as it approaches. The combination of a warm/moist low level airmass and some fairly cold temperatures aloft will yield to not only a presence of elevated instability (we could see MUcape values approach 750-1000 J/KG in spots) but some weak surface-based instability indicated by LI values nearing as low as -2C and SBcape values perhaps as high as 500 J/KG (dependent on any degree of surface heating). TT values are also modeled to be in the upper 40's to near 50F. With a moist llvl airmass in place and enhanced lift (strong isentropic lift thanks to warm front in vicinity) the main threat on Thursday will certainly be downpours with isolated flash flood threat, especially for areas which receive the most rain between now and Thursday. However, portions of southern New England will also be close to the triple point. It will be within this zone where the potential for low topped thunderstorms may form. While typically low topped convection is associated with little to no lightning, this may be a case where there may be a bit more in the way of lightning if any convection develops. If any convection were to develop, the strongest cores would be capable of producing some small hail along with some strong winds, given winds aloft are fairly strong. Slightly diminishing the small hail threat is the lack of stronger steeper mid-level lapse rates. However, during the early morning hours, some models have a swath of near 6.5-7 C/KM move overhead. The best threat for convection may actually be oriented more towards early to late morning, however, can't rule anything out later in the day as the cold front pushes through. Could end up being a SEE TEXT type of day! Link to comment Share on other sites More sharing options...
Professional Lurker Posted April 30, 2014 Share Posted April 30, 2014 Nice write-up, wiz! I doubt we see much of anything besides maybe a few rumbled. Either way, here's hoping! Link to comment Share on other sites More sharing options...
weatherwiz Posted April 30, 2014 Author Share Posted April 30, 2014 Nice write-up, wiz! I doubt we see much of anything besides maybe a few rumbled. Either way, here's hoping! Thanks! The push of fairly decent (for this time of year) MUcape is rather interesting and with TT's hovering in the upper 40's to near 50 certainly keeps this possibility on the table. Models also have some pretty decent lift pushing through southern CT into RI and SE MA during the early AM hours as well. Link to comment Share on other sites More sharing options...
Christina311 Posted April 30, 2014 Share Posted April 30, 2014 I've been watching Thursday for a few days too. It's never too early in the season to be disappointed. Link to comment Share on other sites More sharing options...
weatherwiz Posted April 30, 2014 Author Share Posted April 30, 2014 I've been watching Thursday for a few days too. It's never too early in the season to be disappointed. Looks like we have a small window where some convection would be possible...just have to see if and when that second warm punch moves through and how dewpoints respond. NAM seems a bit aggressive, bumping dews up to 60F into NNE and develops as much as 500-750 J/KG of SBcape. Regardless for whoever warm sectors the heaviest showers are going to be convective in nature and probably produce some gusty winds. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted April 30, 2014 Share Posted April 30, 2014 Nice early summer feel tomorrow for areas south of the pike. THOUGH STRONG LOW- TO MID-LEVEL FORCING COLLOCATED WITH RICHERSTREAM OF GULF MOISTURE SHIFTS OFFSHORE ALONG WITH WIDESPREAD RAINSAND EMBEDDED HEAVIER SHOWERS AND THUNDERSTORMS...WESTERN AND CENTRALPORTIONS OF S NEW ENGLAND BECOME ENVELOPED WITHIN THE WARM-SECTORWHERE H925 TEMPS WARM TO +15C. HIGHS GETTING UP AROUND THE UPPER-60SWITH SEVERAL LOCATIONS LIKELY TOPPING 70-DEGREES!AHEAD OF THE COLD FRONT TO THE REAR OF WHICH DRY-SLOTTING DEVELOPSTHERE MAY BE A PERIOD OF DESTABILIZATION ALLOWING FOR DEVELOPMENT OFSCATTERED THUNDERSTORMS /AS THE WRF-ARW AND WRF-NMM SOLUTIONS WOULDSUGGEST/. EVALUATING MODEL SOUNDINGS...SHOULD THE SUN APPEAR WARMINGTHE BOUNDARY-LAYER CONSIDERABLY...COULD SEE INSTABILITY VALUES UP TO1000 J/KG. BUT THIN CAPES UP AGAINST STRONG SW-NE STRAIGHT-LINE WINDSHEAR INHIBITS THE VERTICAL-EXTENT OF UPDRAFTS KEEPING THEM LOW-TOPPED.ROBUST PWATS UP TO 1.5-INCHES LINGERING...STORMS LIKELY TO BRINGBRIEF HEAVY DOWNPOURS AND PERHAPS URBAN AND POOR DRAINAGE IMPACTS.WILL LIKELY SEE ACTIVITY THROUGH THE AFTERNOON AND EVENING COMMUTE.NOT QUITE CERTAIN ON SEVERE WEATHER IMPACTS...BUT THE SITUATIONBEARS WATCHING AND FURTHER ANALYSIS. Link to comment Share on other sites More sharing options...
weatherwiz Posted April 30, 2014 Author Share Posted April 30, 2014 Well as far as tomorrow goes looks like we will have two windows for thunderstorms. The first window will be in the early morning hours. During this time we will see an increase in theta-e air along with an increase in dewpoints as a warm front pushes through. This will also be enhanced by an increasing LLJ max which moves through early morning hours. The Euro/GFS are bring a pocket of 700-500mb lapse rates of 7 C/KM overhead while the llvl airmass becomes warmer and more moist. This combination actually leads to several hundred J/KG of SBcape and MUcape values withTT's spiking into the lower 50's. Besides the threat for heavier rainfall tomorrow morning we will likely see thunderstorms around as well posing a threat for some small hail and gusty winds. After morning activity models hint at some drying air moving in aloft...this will lead to the possibility of some sun breaking out, especially across eastern NY into W CT/W MA. If this does indeed happen, temps could reach the 70F mark along with dewpoints near 60F, if not a few ticks higher. While mlvl lapse rates do weaken, the presence of a warm and moist llvl airmass coupled with the possibility of some surface heating could lead to another boost of instability. With a cold front sliding east, enough evidence may be in place for another round of heavier downpours and thunderstorms, this time with the main threat with any storms being more strong winds than hail...although given low WBZ's small hail would be a possibility. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted April 30, 2014 Share Posted April 30, 2014 The first true warm sector, high dew day in SNE is always exciting and something we all cherish. Let's enjoy that tomorrow Link to comment Share on other sites More sharing options...
dendrite Posted April 30, 2014 Share Posted April 30, 2014 The first true warm sector, high dew day in SNE is always exciting and something we all cherish. Let's enjoy that tomorrowI thought your first was in Jan? Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 Meh, cloudy and dews near 60F. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted April 30, 2014 Share Posted April 30, 2014 Sun should be out by noon over central and western areas tomorrow..Partial sun anyway. Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 Sun should be out by noon over central and western areas tomorrow..Partial sun anyway. I predict 2-3pm for you. Partial sun anyways. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted April 30, 2014 Share Posted April 30, 2014 I predict 2-3pm for you. Partial sun anyways.We'd much rather you make a prediction on Mem Day weekend. It's only 23 days away. At least what the general pattern should look like Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 We'd much rather you make a prediction on Mem Day weekend. It's only 23 days away. At least what the general pattern should look like Spring is the worst time for long range predictions. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted April 30, 2014 Share Posted April 30, 2014 Convective spike early tomorrow am Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 Convective spike early tomorrow am CT may have the best chance of some rumblestillskins prior to dawn. Link to comment Share on other sites More sharing options...
CT Rain Posted April 30, 2014 Share Posted April 30, 2014 Convective spike early tomorrow am lol nice grab off my twitter account. Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 lol nice grab off my twitter account. Of course...lol. Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 Wiz if anything, Sunday aftn might be something to watch. Link to comment Share on other sites More sharing options...
weatherwiz Posted April 30, 2014 Author Share Posted April 30, 2014 Wiz if anything, Sunday aftn might be something to watch. I"ll take a look. Any brief details you can throw in? Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 I"ll take a look. Any brief details you can throw in? For Sunday? One of those deals where we have a strong s/w moving in, but probably limited instability. It could easily go poof, but as is...it looked a little interesting. Link to comment Share on other sites More sharing options...
weatherwiz Posted April 30, 2014 Author Share Posted April 30, 2014 For Sunday? One of those deals where we have a strong s/w moving in, but probably limited instability. It could easily go poof, but as is...it looked a little interesting. GFS really increases lapse rates...has mlvl lapse rates increase 7-8 C/KM! Strong s/w associated with what looks like a cold pool? Instability should be lacking quite a bit though given how dewpoints look to only be in the low 40's then increasing to mid 40's. Maybe see some scattered pop up stuff? Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 GFS really increases lapse rates...has mlvl lapse rates increase 7-8 C/KM! Strong s/w associated with what looks like a cold pool? Instability should be lacking quite a bit though given how dewpoints look to only be in the low 40's then increasing to mid 40's. Maybe see some scattered pop up stuff? Verbatim it looked like a decent line in NNE. Link to comment Share on other sites More sharing options...
weatherwiz Posted April 30, 2014 Author Share Posted April 30, 2014 Verbatim it looked like a decent line in NNE. Nice! Might be enhanced by Nose of the MLJ? Looked like a decent jet max pushing through Link to comment Share on other sites More sharing options...
CT Rain Posted April 30, 2014 Share Posted April 30, 2014 Could be some gusty winds... that's one hell of an inverted V with very low wbzs and a few hundred joules of cape. Link to comment Share on other sites More sharing options...
CoastalWx Posted April 30, 2014 Share Posted April 30, 2014 Could be some gusty winds... that's one hell of an inverted V with very low wbzs and a few hundred joules of cape. I'm always a fan of strong s/w's coming in like that around here so maybe it's something to keep an eye on. Link to comment Share on other sites More sharing options...
weatherwiz Posted May 1, 2014 Author Share Posted May 1, 2014 starting to see a few isolated showers developing in NY and in NNJ Link to comment Share on other sites More sharing options...
weatherwiz Posted May 1, 2014 Author Share Posted May 1, 2014 couple CG's in NY Link to comment Share on other sites More sharing options...
Typhoon Tip Posted May 1, 2014 Share Posted May 1, 2014 Line of boomer in western mass, literally across the last 3 frames of rad Link to comment Share on other sites More sharing options...
weatherwiz Posted May 1, 2014 Author Share Posted May 1, 2014 Line of boomer in western mass, literally across the last 3 frames of rad They have been trying their best to get some vertical height but like mentioned in BOX AFD shear is so strong and with such weak updrafts thanks to weak Cape values they are just getting torn apart...this line though getting up to the 20K mark. Link to comment Share on other sites More sharing options...
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