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April 11 Severe Threat


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And to think some of the same areas that see convection tomorrow could awake to a surprise wet snow on Wednesday morning. :snowman: See the NAM....

Some classic inverted-v signatures on some of these soundings across PA...definitely more suggestive of damaging winds rather than tornadic activity but any discrete cells will quickly take on supercell characteristics. Some very nice cape profiles too.

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I'm really intrigued to see what the SPC will do. Since there may be issues with regards to the degree of instability this outlook may be on the more conservative side...always a good thing though in this part of the country until the situation becomes much more clear.

I could definitely see 5% TOR, 15% hail and 30% wind though...if the degree of instability becomes much more clear by the AM and it appears we'll see 1500-2000 J/KG of SBcape/MLcape and LI values around -4C I could see 10% TOR contour for parts of PA.

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Surprisingly loaded soundings for KBUF, KPIT and KALB this morning....BUF's and PIT's are the actual soundings. ALB's first sounding is the actual and modified (#2) for a temp of 78 DP of 58 and doing this mod adds little to increasing CAPES. DCAPES are impressive especially at ALB and PIT and indicate potential for damaging winds; the EHI on/from all soundings is pretty impressive too!

Modified KALY:

Now its a matter of can manifest all this CAPE

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Thins appear to be coming together fairly nicely...temps are really continuing to jump up and instability numbers as well. It will be interesting to see what happens with the ML lapse rates as the afternoon goes on. Much of this area is under a pretty steep lapse rate environment with ML lapse rates up over 7.5 C/KM. If this can maintain this will really help yield to those impressive Cape profiles later on. Helicity values are also fairly high.

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LCL's are fairly high, not surprising given how the dewpoints are only around 60F and forecast soundings have the inverted-v look so it might be a little more difficult to spawn a tornado but it's certainly not impossible. With daytime heating occurring though the low level lapse rates are really starting to steepen and this should really help with the threat for damaging winds. Dcape values already approaching 1000 J/KG! That's not to shabby.

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Very mild here now at 78. It is dark and cloudy though...... Gusty sw wind driven heat here...

Thins appear to be coming together fairly nicely...temps are really continuing to jump up and instability numbers as well. It will be interesting to see what happens with the ML lapse rates as the afternoon goes on. Much of this area is under a pretty steep lapse rate environment with ML lapse rates up over 7.5 C/KM. If this can maintain this will really help yield to those impressive Cape profiles later on. Helicity values are also fairly high.

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Does anybody else notice that the biggest severe events here are either underforecasted or essentially not forecasted, while the expected big severe days (like today) tend to bust? Maybe its just me.

Well sometimes I think when a few parameters look favorable or look juicy what looks bad gets overlooked. Like for today there were always a few things that had me concerned; such as the ML lapse rates decreasing as the day went on and the sfc low weakening as the day went on. The strength of the lift I think was a question to.

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Does anybody else notice that the biggest severe events here are either underforecasted or essentially not forecasted, while the expected big severe days (like today) tend to bust? Maybe its just me.

Yeah, I share this sentiment. For example, there have been a few confirmed tornadoes around C NY / NE PA within the last few years that have been associated with TCU's, and thus, they were virtually undetectable and there were consequently no warnings issued on them.

Just heard a rumble of thunder from over the hill... storms about to descend on the I-81 corridor here...

post-538-0-36595900-1302561783.gif

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mcd0416.gif

MESOSCALE DISCUSSION 0416

NWS STORM PREDICTION CENTER NORMAN OK

0543 PM CDT MON APR 11 2011

AREAS AFFECTED...MD/CNTRL AND ERN PA/CNTRL AND ERN NY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 112243Z - 112345Z

A FEW THUNDERSTORMS CAPABLE OF DMGG WINDS MAY DEVELOP FROM MD NWD INTO PORTIONS OF CNTRL/ERN NY. GIVEN EXPECTED TRENDS AT THE MOMENT...A WW IS NOT ANTICIPATED...BUT THE AREA WILL CONTINUE TO BE MONITORED.

STRONG DIURNAL HEATING AND LOW LEVEL WARM ADVECTION REGIME HAS LED TO WELL ABOVE NORMAL TEMPERATURES ACROSS THE NORTHEAST...WHILE DEW POINTS IN THE LOWER 60S HAVE REACHED MD/ERN PA...AND MID TO UPPER 50S FARTHER N. HOWEVER...APPEARANCE OF GENERALLY STRATUS CLOUDS...LACK OF TOWERING CU/CONVECTIVE TYPE CLOUD STRUCTURES ON VISIBLE SATELLITE IMAGERY AND LACK OF LIGHTNING WITH THE EXCEPTION OF CNTRL NY INDICATES THAT STRONG CONVECTIVE INHIBITION STILL REMAINS. PER RECENT WV IMAGERY...AN UPPER TROUGH AND IMPLIED UPPER ASCENT STILL REMAINS WEST OF THE AREA OVER SERN ONTARIO SWD INTO THE OH VALLEY...AND GIVEN NEUTRAL TO WEAK HEIGHT FALLS THROUGH PEAK DIURNAL HEATING...MAY HAVE ALSO LIMITED MORE WIDESPREAD CONVECTIVE DEVELOPMENT. HOWEVER...RECENT RADAR IMAGERY INDICATES THAT A PREFRONTAL TROUGH EXTENDING THROUGH CNTRL NY SWD INTO ERN PA THEN SWWD THROUGH WV MAY PROVIDE SUFFICIENT FORCING FOR ASCENT... ALLOWING A FEW THUNDERSTORMS TO DEVELOP WHERE CINH IS WEAKER.

ADDITIONAL CONVECTION MAY BE POSSIBLE AS THE AFOREMENTIONED UPPER WAVE/HEIGHT FALLS AND ASSOCIATED SURFACE COLD FRONT QUICKLY APPROACH FROM THE WEST...THOUGH RADIATIONAL COOLING WILL LIKELY LIMIT A MORE WIDESPREAD THREAT OF SEVERE THUNDERSTORMS. HOWEVER...SHOULD STORMS DEVELOP...STRONG WIND FIELDS WOULD SUPPORT DMGG WINDS.

..HURLBUT.. 04/11/2011

ATTN...WFO...BTV...OKX...ALY...PHI...BGM...BUF...CTP...LWX...

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Not enough sun...........Didn't come out until almost noon and never cleared out for any extended period enough to really destabilize things around here. Garden variety crap at best this evening with some gusty breezes mixing down at times. :frostymelt:

I'm not really sure if enough sun was the main issue here, even if it was 3-5F warmer you're not really going to destabilize much more with Td's only around 60F and ML lapse rates weakening to around 6 C/KM.

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This is why you keep rooting for snow events even into mid/late April. Yes the odds are definitely under 50% now, but there is still a better chance of a snowstorm in Upstate NY than a severe wx outbreak.... Around May you (realistically) have a better shot at some severe wx....

Not enough sun...........Didn't come out until almost noon and never cleared out for any extended period enough to really destabilize things around here. Garden variety crap at best this evening with some gusty breezes mixing down at times. :frostymelt:

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This is why you keep rooting for snow events even into mid/late April. Yes the odds are definitely under 50% now, but there is still a better chance of a snowstorm in Upstate NY than a severe wx outbreak.... Around May you (realistically) have a better shot at some severe wx....

Maybe some flakes next Monday, Rick, after the cold front from the Midwest storm comes through?

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Maybe ...but I'd love to see a final couple inches in latter April to put a cap on the season. :snowman: But if it's over then so be it .....six months till my annual weekend in Stowe where I usually see my first snow in the high terrain of the Greens.

Maybe some flakes next Monday, Rick, after the cold front from the Midwest storm comes through?

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