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Severe Weather possible weekend of the 21st?


weatherwiz

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This will make tracking some of these storms a little bit more challenging...

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE ALBANY NY
331 PM EDT WED JUL 17 2013
 
...KENX DOPPLER RADAR TO BE OFFLINE THROUGH EARLY AUGUST...
 
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE THROUGH EARLY AUGUST.  A MAJOR HARDWARE FAILURE WITH THE RADAR HAS BEEN IDENTIFIED.  FIXING THIS WILL REQUIRE HEAVY DUTY EQUIPMENT AND A TEAM OF EMPLOYEES FROM THE RADAR OPERATIONS CENTER.  WE APOLOGIZE FOR THE INCONVENIENCE.
$$
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This will make tracking some of these storms a little bit more challenging...

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE ALBANY NY
331 PM EDT WED JUL 17 2013
 
...KENX DOPPLER RADAR TO BE OFFLINE THROUGH EARLY AUGUST...
 
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE THROUGH EARLY AUGUST.  A MAJOR HARDWARE FAILURE WITH THE RADAR HAS BEEN IDENTIFIED.  FIXING THIS WILL REQUIRE HEAVY DUTY EQUIPMENT AND A TEAM OF EMPLOYEES FROM THE RADAR OPERATIONS CENTER.  WE APOLOGIZE FOR THE INCONVENIENCE.
$$

 

 

 

Oh that's bad, very bad. And I was just about to post about how the RAP is showing some really interesting numbers for the Albany area this evening, even breaks out precip... Boy, bad timing for a hardware failure. There's really no other radar that reaches that area.

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This will make tracking some of these storms a little bit more challenging...

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE ALBANY NY
331 PM EDT WED JUL 17 2013
 
...KENX DOPPLER RADAR TO BE OFFLINE THROUGH EARLY AUGUST...
 
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE THROUGH EARLY AUGUST.  A MAJOR HARDWARE FAILURE WITH THE RADAR HAS BEEN IDENTIFIED.  FIXING THIS WILL REQUIRE HEAVY DUTY EQUIPMENT AND A TEAM OF EMPLOYEES FROM THE RADAR OPERATIONS CENTER.  WE APOLOGIZE FOR THE INCONVENIENCE.
$$

 

that's too bad. and there's no TDWR up that way to atleast help compensate. 

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Isn't there a an "MCS checklist" -- seems I remember hearing about one that was derived but I may be imagining that.  

 

We know there is a WINDEX one - 

 

Anyway, I was wondering if an MCS might turn right and Derecho later on.  

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I have the cameras ready here in the Champlain Valley

\

 

Nice!  You film too?     I have a couple of favorite spots where I can get a nice unimpeded view across valley floors.  I like to put my HD cam on tri-pot with polarization lens.  Then engineer the recording to a slightly faster speed and geek out over cloud formations.   Haven't had many chance the last 2 years, but I did get a nice supercell shot back in 2010. 

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Hmm, I did find this in an Abstract at EMS

 

Forecasting the maintenance of Lake Michigan-crossing mesoscale convective systems (MCSs) is an important concern for operational forecasters over lower Michigan. Recent research has implicated numerous synoptic and mesoscale features as conducive to MCSs surviving a west to east trip across Lake Michigan. Some of these features include: ample downstream instability across lower Michigan, a robust low-level jet impinging on the MCS, the presence of an elevated mixed layer, and a right-entrance region of an upper-level jet streak over lower Michigan.

This presentation will assess the applicability of this recent research to an operational forecasting setting. The National Weather Service office in Gaylord, Michigan developed a checklist incorporating seven different parameters that differentiate between MCS persistence and dissipation, with the goal of giving forecasters a useful tool to anticipate the arrival of severe weather. This checklist was evaluated for 68 cases during the 2005-2011 warm seasons. During this period, 42% of cases that featured convection upstream over Wisconsin were successfully able to move into lower Michigan and also produce at least one severe weather report. The results indicate that the checklist has utility in discriminating between cases that survive lake crossing and those that do not. This utility is increased when looking at cases that produced more widespread (≥10 reports) severe weather. From this initial assessment, the checklist was modified slightly and will be used operationally during the 2013 warm season. Preliminary results from this real-time operational use will also be discussed.

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IZG and the foothills will win again

That would be interesting. I've yet to see anything during nighttime even approaching svr in 15 yr here. Some nice after-dark lightshows (none in the past 4-5 yr) but nothing for wind, hail, +RA. Looks like several chances before the dry air arrives.

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I like taking a look at the MCS Maintenance parameter in situations like this. The values aren't too impressive today, but...

 

Probability of MCS Maintenance

348 warm-season MCS proximity soundings from a variety of MCS types were used to develop this parameter. Though hypothesis testing and discriminant analysis on hundreds of sounding parameters, the following four parameters were selected to develop the probabilities: 

1) maximum bulk shear (m/s) in the 0-1 and 6-10 km layer
2) 3-8 km lapse rate (degrees C/km)
3) most unstable CAPE
4) 3-12 km mean wind speed (m/s)

Reference: 
Coniglio, M.C., and S.F. Corfidi, 2006: Forecasting the speed and longevity of
    severe mesoscale convective systems. Preprints, Severe Local
    Storms Symposium, Amer. Meteor. Soc., Atlanta, GA, CD-ROM.

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I like taking a look at the MCS Maintenance parameter in situations like this. The values aren't too impressive today, but...

 

Probability of MCS Maintenance

348 warm-season MCS proximity soundings from a variety of MCS types were used to develop this parameter. Though hypothesis testing and discriminant analysis on hundreds of sounding parameters, the following four parameters were selected to develop the probabilities: 

1) maximum bulk shear (m/s) in the 0-1 and 6-10 km layer

2) 3-8 km lapse rate (degrees C/km)

3) most unstable CAPE

4) 3-12 km mean wind speed (m/s)

Reference: 

Coniglio, M.C., and S.F. Corfidi, 2006: Forecasting the speed and longevity of

    severe mesoscale convective systems. Preprints, Severe Local

    Storms Symposium, Amer. Meteor. Soc., Atlanta, GA, CD-ROM.

 

 

I think this is what I was remembering. Yeah -

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Awesome AFD from BTV:

Near term /until 6 am Thursday morning/... as of 250 PM EDT Wednesday...severe watch #416 continues until midnight for entire County Warning Area. Expecting several rounds of storms...first across the slv/Ottawa Valley and northern New York between 4pm and 6pm...then secondary and more potent line of storms approaches northern zones between 22-00z this evening. This will have potential for a well organized line of storms with enhanced bowing segments possible. Still thinking the primary threat will be strong/damaging winds...with isolated/scattered power outages/trees down. Thinking line will enter cpv between 01-02z...and dissipate by 03z across our eastern County Warning Area. The main concentration will be across northern New York into central/northern Vermont. Forecast challenge will be timing of the convection weakening/moving east of our County Warning Area late this evening...followed by fog potential overnight. Water vapor shows potent short wave energy entering the Ottawa Valley at this time...which will continue to develop a line of severe storms across our central/northern County Warning Area this evening. This system is prognosticated to be east of County Warning Area by 06z tonight...which combined with loss of daytime heating/instability will result in a decrease in showers/storms. Will mention chance/likely probability of precipitation through 03z...along with enhanced wording for winds/heavy rainfall. Rap 13 shows deep layer shear values between 35 and 40 knots across our northern County Warning Area...along with surface based cape around 2000 j/kg...persisting through the evening hours. This will provide enough instability to keep storms strong/severe into the evening hours...with primary threat being damaging winds. Given...very warm dewpoints and southerly winds...expect lows mainly in the m60s mountains to l70s warmer valleys with patchy fog possible. && Short term /6 am Thursday morning through Friday night/... as of 340 PM EDT Wednesday...the forecast challenge will be areal coverage/intensity of storms each afternoon/evening through Friday night. Overall...expecting an active couple days with several rounds of strong to possibly severe storms...along with very hot and humid conditions...persisting through Friday. Thursday into Thursday night...a little more uncertainty on placement of ulvl support...position of deepest moisture...and associated surface boundary...especially given this evenings convection. Latest 12z GFS shows better dynamics and relative humidity fields...along with the associated convection across our southern County Warning Area...while nam12 shows potent 500 mb energy and good relative humidity entering the slv by 18z and moving into the cpv by 21z...and through Vermont by 03z Friday. Both NAM/GFS show favorable shear/instability parameters for organized convection...along with a leftover surface boundary/terrain for low level trigger...but ulvl support is weaker. Sounding profiles show cape values between 2000 and 2500 j/kg and best 0 to 6km shear of 40 near near the international border...closest to the middle level wind maximum. Once again...primary severe weather threat will be isolated pulse strong and damaging winds. In addition...local 2km and 4km are very robust with development of composite reflectivity fields...but maybe a bit overdone on areal coverage...based on previous experience. Will continue to mention chance probability of precipitation from 16z through 03z...thinking activity will start earlier on Thursday...based on position of short wave energy and dissipate by early evening. Prognosticated 850 mb and 925mb temperatures cooler slightly and support highs in the m80s mountains to l90s warmer valley locations...with very similar overnight lows to recent nights...m60s to l70s. On Friday...mid/upper level trough across the Great Lakes approaches our western County Warning Area...along with several embedded S/w's in the fast west/southwest follow aloft. This energy/hght falls...combined with better 850 to 500mb relative humidity profiles will result in more afternoon/evening showers/storms on Friday. NAM/GFS continue to show best 0 to 6 km shear values between 40 and 45 knots across our central/northern County Warning Area...along with cape values around 2000 j/kg. So a few strong/severe storms will be possible. Some uncertainty on overall organization and timing of individual S/w's in fast follow aloft...along with placement of pre-frontal troughs. Storm Prediction Center day 3 highlights our central/northern County Warning Area in slight risk. Precipitable waters between 1.50 and 2.0" supports the potential for heavy rainfall...but with storm motion of 20 to 30 knts...not anticipating any significant Hydro problems. Maybe some minor poor drainage/urban type stuff. Prognosticated 850 mb temperatures between 16-18c and 925mb temperatures between 22-24c...support highs once again well into the M/u 80s mountains to m90s warmer valley locations...especially SW downslope areas like pbg. Heat index values will once again approach 100 degrees in a few locations. && Long

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Deep layer shear is pretty unimpressive down this way on Saturday. That said, instability looks good, frontal timing good, and nice jet dynamics with the right entrance region of that jet streak sagging south.

 

25 knots of so is OK but not great.

GFS and NAM keep winds awfully westerly on Saturday - not great for severe. Would like to see those back otherwise we run the risk of downsloping and mixing out some of the better dews and also keeping deep layer shear fairly meh. 

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Deep layer shear is pretty unimpressive down this way on Saturday. That said, instability looks good, frontal timing good, and nice jet dynamics with the right entrance region of that jet streak sagging south.

 

25 knots of so is OK but not great.

GFS and NAM keep winds awfully westerly on Saturday - not great for severe. Would like to see those back otherwise we run the risk of downsloping and mixing out some of the better dews and also keeping deep layer shear fairly meh. 

 

Probably just going to end up with 30% wind probs...don't think we will see a mod risk type setup unless we do see deep layer shear increase.  What does help though is inverted-v signatures.  

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