Severe wx in the northeast...What went wrong?----->

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Severe wx in the northeast...What went wrong?----->

#1 Postby RNS » Wed Nov 19, 2003 6:29 pm

much of our region was too stable to warrent a large scale severe wx outbreak this afternoon. while wind profiles are very favorable (Ie...BL-6KM Shear, SR helicity, very good H5 and H85 jet streaks, strong s/w energy, low LFC and LCL heights), we are severely lacking moisture and instability. MUCAPE is only around 250 J/kg (since there has been little in the way of sfc heating, and dewpoints are maxing our around 62F), the thermodynamic environment is crappy at best...lol.

SBC and CIN:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/sbcp.html

also, note that most unstable LI/s are still positive in the warm sector (remember when the temperature of the parcel is cooler than the temperature of the environment, the parcel will sink as the cold air is more dense, thus one would need sufficient UVM to lift the cooler parcels to the LFC).

http://www.spc.noaa.gov/exper/mesoanalysis/s1/muli.html

As mentioned....LLVL shear profiles were IMO extremely impressive

0-3 KM AGL Storm-relative Helicity:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/srh3.html

Note that the best SRH (on the order of up to 750 m2/s2)
set-up should we have better instability in place in the warm sector.

0-1 KM AGL SRH:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/srh1.html

Boundary layer to 6KM deep layer Shear:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/shr6.html

This would be an AWESOME severe wx scenario given better thermodynamic profiles. Also, lapse rates are rather weak due to the cooler air in place.

The narrow line of tstms ahead of the cold front is feeding off of a very strong 65KT LLVL H85 jet, and the strong UVM which exists in the exit region of the speed max, aided by what little instability may be present within the tounge of surging dewpoints coming into SE PA.

Now that the main speed max has moved to the north, the best UVM associated with it has moved into NY state, much of the reason why the line is breaking up.

SFC TMP, and Td:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/ttd.html

850-500 hPa wind crossover:

http://www.spc.noaa.gov/exper/mesoanaly ... xover.html

it is the Upper Level divergence associated with the enterance region of the h5 jet maximum and LLVL convergence particular to the H85 jet core exit region, which created the best environment for sufficient UVM.

also...the 850-500 hPa wind crossover would only indicate slight backing of winds with height. the best backing was noted close to the NY border, as H85 winds were more SE in this region as compared to S or SSE...further south.

for a large scale outbreak, i would want to see the favorable deep layer shear coinciding with the best instability in the warm sector to elevate EHI indicies above 1.0 (which is usually consistent with tornadic activity).

Since,

EHI (Energy-Helicity Index) = CAPE*Shear / 160000

if we had MU CAPE of even 1000 j/kg, and given the very strong deep layer shear, the combination of the favorable wind profiles and thermodynamic environment, would have resulted in a much more severe event.

3KM EHI:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/ehi3.html

1KM EHI:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/ehi1.html

Note that there is little in the way of positive EHI left.

LPL Heights and MUCAPE:

http://www.spc.noaa.gov/exper/mesoanalysis/s1/mucp.html

the LPL or Lifted Parcel Level (In Meters AGL) is used to distinguish the layer which contains the most unstable parcel.

http://www.spc.noaa.gov/exper/mesoanalysis/s1/

IF this was september or even early october...it could have been much worse.

NOTE: since the SPC mesoanalysis graphics are updated hourly, what you see in the figures may not reflect the information in my post as it becomes older.
Last edited by RNS on Wed Nov 19, 2003 6:51 pm, edited 2 times in total.
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weatherlover427

#2 Postby weatherlover427 » Wed Nov 19, 2003 6:37 pm

None of your images work, RNS. :(
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#3 Postby RNS » Wed Nov 19, 2003 6:42 pm

yea...i know...im changing them to links as we speak
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weatherlover427

#4 Postby weatherlover427 » Wed Nov 19, 2003 6:45 pm

ok thanks ;)
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#5 Postby wxid » Wed Nov 19, 2003 6:55 pm

i know enough went right i had to take a canoe home from work ! :eek:
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#6 Postby RNS » Wed Nov 19, 2003 7:00 pm

that part was fine...i was doing the backstroke thru my basement an hour ago...lol. 2 inches of water sitting down there and the sumpump is having a hard time draining it out.

this is the 5th time my basement has become a swimming pool since i bought the place in may
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#7 Postby wxid » Wed Nov 19, 2003 7:46 pm

RNS wrote:that part was fine...i was doing the backstroke thru my basement an hour ago...lol. 2 inches of water sitting down there and the sumpump is having a hard time draining it out.

this is the 5th time my basement has become a swimming pool since i bought the place in may



......Jeeeeeez! :eek:
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#8 Postby RNS » Wed Nov 19, 2003 7:52 pm

Yea it was rough...I recorded 3.31" of rain, ( here in saylorsburg...which is my exact location). Most of it fell in the past 4 hours though since i didint check the rain gauge this morning, im not sure how much of that total was from last night/s and this mornings activity
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#9 Postby Stormsfury » Wed Nov 19, 2003 7:59 pm

RNS wrote:Yea it was rough...I recorded 3.31" of rain, ( here in saylorsburg...which is my exact location). Most of it fell in the past 4 hours though since i didint check the rain gauge this morning, im not sure how much of that total was from last night/s and this mornings activity


RNS, I'll trade you some rainfall ... I barely picked up 2/3" of an inch of rain, however ... the ETA/GFS/RUC progs last night for CHS verified to a T.
Although, this occurred only 2½ miles to my SSW

0947 AM SUMMERVILLE SC WIND DAMAGE
11/19/03 DORCHESTER TREE DOWN BLOCKING ROAD AT
KINGS GRANT SUBDIVISION.

Some parts of NC picked up as much as 10" of rain ... classic upslope (orographic lifting) ...

SF
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#10 Postby wxid » Wed Nov 19, 2003 8:01 pm

Yeah, down here we had 2-4 feet of flooding near DC and i think the whole month(s) precip of Oct and Nov fell out of the sky in about 1 hour !!! No exaggeration! Weird wx year, IMO.
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#11 Postby RNS » Wed Nov 19, 2003 8:03 pm

I noticed. the oragraphics were also much of the reason why i received more rainfall up here than what was seen elsewhere.

and we still totaling things up.
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#12 Postby RNS » Wed Nov 19, 2003 8:10 pm

yes...it has been a very crazy wx year so far...and it only looks to get more out of control as we head into DEC.

Also...im beginning to form my ideas for what i believe is going to be a signifcant snow event across the eastern part of the country between the first and seventh. right now i think it may be a supressed event, however given the seasonal variation, the system may track far enough north to give the major cities their first snowfall. dont get too excited yet...but based on my analogs for DEC and the trend in the operational data...im becoming more and more convinced that something is up.

I dont think it will be an inland runner given the very strong blocking scenario which is going to be setting up, however, so im torn between a coastal event or a supressed system.

the 12z GFS heald back some energy in the SW at day 13, but i dont think it handles the pattern further downstream very well given the blocking that will be in place at that point.
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#13 Postby wxid » Wed Nov 19, 2003 8:18 pm

Interesting indeed! No hopes are getting up here, after past 3+ years of letdowns, i try my best to suppress hope til i open the door to 12 inches! I am in Salisbury, MD (eastern shore peninsula) and we usually have changeovers to rain. Your area rules !!! Ever heard of Milford, PA? Vacation up near there sometimes, love it!!
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#14 Postby RNS » Wed Nov 19, 2003 8:39 pm

If were talking about the same milford PA, yea it is a great area.

i think that SBY will have a 10+ event this coming winter
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#15 Postby JCT777 » Thu Nov 20, 2003 10:02 am

Sounds very interesting for the first week of December, RNS. Almost sounds like last year, when DCA, BWI and PHL picked up their first snowfall of the season on December 5. Obviously the set-up is not the same, but hopefully the rest of winter brings a good amount of cold and snow (like last winter did).
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