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2015 Severe Weather Thread


Hvward

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I don't get why storms are having so much trouble today, with all of the instability.  They can't grow and keep petering out.  What's the deal?

 

Shear....the updrafts need to be vented in order to maintain, if they don't get sheared then they build a cold pool and eventually the warm updraft cant hold up the cold pool and it collapses, typical pulse type storms......that said shear is getting better over part of the area and will continue to do so as the afternoon progresses, Hi Res still has line forming NW of RDU in a hr or so and dropping SE......

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Afternoon near term...

CURRENT CONVECTION BREAKING OUT OVER THE EASTERN COUNTIES IS

PRODUCING SOME LIGHTNING BUT WHILE THERE IS SOME DECENT INSTABILITY

BUILDING ALONG A NEAR STATIONARY FRONTAL ZONE...THERE IS NOT ENOUGH

FORCING AT THE MOMENT TO SUSTAIN ACTIVITY FOR TOO LONG. THEREFORE

ONLY EXPECTING ISOLATED TO SCATTERED CONVECTION THIS AFTERNOON AND

INTO THE EARLY EVENING. THAT BEING SAID...FORCING WILL BEGIN TO

INCREASE SUBSTANTIALLY FROM THE NORTH AS A WAVE MOVES DOWN OUT OF

THE OHIO VALLEY...ACROSS CENTRAL VA AND INTO THE NE PORTIONS OF

NORTH CAROLINA. WITH EFFECTIVE SHEAR INCREASING TO NEAR 40 KTS...AND

HELICITY ON THE RISE AS WELL...CHANCES ARE INCREASING FOR AN

ORGANIZED LINE OF CONVECTION MOVING THROUGH OUR FAR NORTHEASTERN

COUNTIES LATER TONIGHT AROUND OR JUST BEFORE 03Z. THE MOST LIKELY

THREAT IN THIS SCENARIO WOULD BE DAMAGING WINDS WITH AN OUTSIDE

CHANCE OF A BRIEF TORNADO SPINUP ALONG THE LINE. AS A RESULT OF

CONDITIONS BECOMING MORE FAVORABLE FOR SEVERE WEATHER THE STORM

PREDICTION CENTER IS EXTENDING AN AREA OF ENHANCED RISK DOWN ACROSS

HALIFAX...WARREN...AND VANCE COUNTIES WITH CONTINUED SLIGHT RISK

ELSEWHERE.

SOME MITIGATING FACTORS AGAINST POTENTIAL SEVERE WEATHER INCLUDE THE

LATER TIMING OF THIS FEATURE REACHING NC WHICH WILL BE WELL AFTER

PEAK HEATING CONCLUDES. IN ADDITION A CAP IS EXPECTED TO FORM WHICH

WOULD CUT OFF SURFACE BASED INSTABILITY..BUT COULD STILL SUSTAIN

ELEVATED CONVECTION WELL INTO THE OVERNIGHT HOURS BUT MOST LIKELY

FOR POINTS EAST OF OUR CWA. WOULD EXPECT ANY LINGERING CONVECTION TO

CLEAR THE AREA BY 9Z.

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Shear....the updrafts need to be vented in order to maintain, if they don't get sheared then they build a cold pool and eventually the warm updraft cant hold up the cold pool and it collapses, typical pulse type storms......that said shear is getting better over part of the area and will continue to do so as the afternoon progresses, Hi Res still has line forming NW of RDU in a hr or so and dropping SE......

 

 

Afternoon near term...CURRENT CONVECTION BREAKING OUT OVER THE EASTERN COUNTIES IS PRODUCING SOME LIGHTNING BUT WHILE THERE IS SOME DECENT INSTABILITY BUILDING ALONG A NEAR STATIONARY FRONTAL ZONE...THERE IS NOT ENOUGH FORCING AT THE MOMENT TO SUSTAIN ACTIVITY FOR TOO LONG. THEREFORE ONLY EXPECTING ISOLATED TO SCATTERED CONVECTION THIS AFTERNOON AND INTO THE EARLY EVENING. THAT BEING SAID...FORCING WILL BEGIN TO INCREASE SUBSTANTIALLY FROM THE NORTH AS A WAVE MOVES DOWN OUT OF THE OHIO VALLEY...ACROSS CENTRAL VA AND INTO THE NE PORTIONS OF NORTH CAROLINA. WITH EFFECTIVE SHEAR INCREASING TO NEAR 40 KTS...AND HELICITY ON THE RISE AS WELL...CHANCES ARE INCREASING FOR AN ORGANIZED LINE OF CONVECTION MOVING THROUGH OUR FAR NORTHEASTERN COUNTIES LATER TONIGHT AROUND OR JUST BEFORE 03Z. THE MOST LIKELY THREAT IN THIS SCENARIO WOULD BE DAMAGING WINDS WITH AN OUTSIDE CHANCE OF A BRIEF TORNADO SPINUP ALONG THE LINE. AS A RESULT OF CONDITIONS BECOMING MORE FAVORABLE FOR SEVERE WEATHER THE STORM PREDICTION CENTER IS EXTENDING AN AREA OF ENHANCED RISK DOWN ACROSS HALIFAX...WARREN...AND VANCE COUNTIES WITH CONTINUED SLIGHT RISK ELSEWHERE. SOME MITIGATING FACTORS AGAINST POTENTIAL SEVERE WEATHER INCLUDE THE LATER TIMING OF THIS FEATURE REACHING NC WHICH WILL BE WELL AFTER PEAK HEATING CONCLUDES. IN ADDITION A CAP IS EXPECTED TO FORM WHICH WOULD CUT OFF SURFACE BASED INSTABILITY..BUT COULD STILL SUSTAIN ELEVATED CONVECTION WELL INTO THE OVERNIGHT HOURS BUT MOST LIKELY FOR POINTS EAST OF OUR CWA. WOULD EXPECT ANY LINGERING CONVECTION TO CLEAR THE AREA BY 9Z.

 

Sounds like RAH agrees. Still, even though they say things are increasing for instability and severe weather, it still might not happen because it could be too late. Just have to wait and see.

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Sounds like RAH agrees. Still, even though they say things are increasing for instability and severe weather, it still might not happen because it could be too late. Just have to wait and see.

 

Being after peak heating etc doesnt always mean no severe ( look at Stormfury's video ) that cap they talk about at the surface later is the same one that broke down in his area late last night and you see what happens.....that doesn't mean it will happen for a given location even if the inversion breaks down but in my experience when you have prolonged heating like we have had eventually all that energy getting stored has to be equalized...almost every heatwave around here ends with a few days of good storms.

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Shear....the updrafts need to be vented in order to maintain, if they don't get sheared then they build a cold pool and eventually the warm updraft cant hold up the cold pool and it collapses, typical pulse type storms......that said shear is getting better over part of the area and will continue to do so as the afternoon progresses, Hi Res still has line forming NW of RDU in a hr or so and dropping SE......

 

Still, you'd think the pop ups would be more vigorous...at least for a little while.

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What I take away from the RAH disco is that the best potential for activity is in the NE and eastern part of the state.  If we don't see something firing over or just n/nw of the Triangle in an hour or two, I think only isolated activity will occur there, at best.

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What I take away from the RAH disco is that the best potential for activity is in the NE and eastern part of the state.  If we don't see something firing over or just n/nw of the Triangle in an hour or two, I think only isolated activity will occur there, at best.

 

Latest trend in the models is to have scattered pulsey stuff now and then a more organized squall line in here overnight like 9-12ish, with the worst focused along the border and NE NC, but still a good hit for the Triangle to the east....

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Latest trend in the models is to have scattered pulsey stuff now and then a more organized squall line in here overnight like 9-12ish, with the worst focused along the border and NE NC, but still a good hit for the Triangle to the east....

 

Good deal.  I haven't looked at the short range stuff today.  Would be nice to see a decent storm for a change.

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Good deal.  I haven't looked at the short range stuff today.  Would be nice to see a decent storm for a change.

 

Nothing earth shattering but it should at least rain lol...still if it can get more rooted to the surface it could be pretty intense.....I am  soooooo jealous of Stormsfury video from last night I haven't seen anything that good since July 1 2012

 

Its currently 90 with a 77 DP and a heat index of 104 so there is plenty to work with if we can just get it lifted to 20-30K + feet

 

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Nothing earth shattering but it should at least rain lol...still if it can get more rooted to the surface it could be pretty intense.....I am  soooooo jealous of Stormsfury video from last night I haven't seen anything that good since July 1 2012

 

Its currently 90 with a 77 DP and a heat index of 104 so there is plenty to work with if we can just get it lifted to 20-30K + feet

 

 

 

It seems we have had plenty to work with the last couple of weeks with this heatwave, but nothing really big has happened with getting storms. Maybe some very isolated stuff, but that's it. Maybe it will produce the next couple of days. If not, it would mean the biggest storms we have had around here came on a day when there was no talk of severe weather. Sill batting zero for the days when there was talk about the potential for severe weather.

 

But I am getting ahead of things. Let's wait and see how the next few days work out.

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Shear....the updrafts need to be vented in order to maintain, if they don't get sheared then they build a cold pool and eventually the warm updraft cant hold up the cold pool and it collapses, typical pulse type storms......that said shear is getting better over part of the area and will continue to do so as the afternoon progresses, Hi Res still has line forming NW of RDU in a hr or so and dropping SE......

There's one little storm nublet that's been forming and reforming over northern Orange county for the past hour. Maybe that's the beginning, but I'm not going to hold my breath.
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CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 251942Z - 252115Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...ISOLATED SUPERCELLS ARE POSSIBLE THIS AFTERNOON WITH A
THREAT OF LARGE HAIL...DAMAGING WIND...AND POSSIBLY A TORNADO OR
TWO. THE THREAT WILL TRANSITION TO AN ENHANCED WIND THREAT THIS
EVENING AS STORMS INCREASE IN COVERAGE.

 

10488189_1085863921443662_53244940486426

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There's one little storm nublet that's been forming and reforming over northern Orange county for the past hour. Maybe that's the beginning, but I'm not going to hold my breath.

* SEVERE THUNDERSTORM WARNING FOR...  ORANGE COUNTY IN CENTRAL NORTH CAROLINA...  SOUTHWESTERN DURHAM COUNTY IN CENTRAL NORTH CAROLINA...* UNTIL 530 PM EDT* AT 434 PM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM  CAPABLE OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS  OF 58 MPH. THIS STORM WAS LOCATED OVER HILLSBOROUGH...AND MOVING  SOUTHEAST AT 15 MPH.* LOCATIONS IMPACTED INCLUDE...  DURHAM...CHAPEL HILL...HILLSBOROUGH...CARRBORO...SCHLEY...ENO RIVER  STATE PARK...EFLAND AND LAKE JORDAN.
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Watch out for parts of the area now.

 

 URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 353
   NWS STORM PREDICTION CENTER NORMAN OK
   450 PM EDT THU JUN 25 2015

   THE NWS STORM PREDICTION CENTER HAS ISSUED A

   * SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
     SOUTHERN MARYLAND
     NORTHEASTERN NORTH CAROLINA
     CENTRAL AND SOUTHERN VIRGINIA
     COASTAL WATERS

   * EFFECTIVE THIS THURSDAY AFTERNOON FROM 450 PM UNTIL MIDNIGHT
     EDT.

   * PRIMARY THREATS INCLUDE...
     SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
     ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE
     A TORNADO OR TWO POSSIBLE

   SUMMARY...SUPERCELL STORMS WITH A THREAT FOR ISOLATED LARGE
   HAIL...DAMAGING WIND AND PERHAPS A TORNADO OR TWO WILL BE LIKELY
   THROUGH MID EVENING. STORMS MAY EVENTUALLY GROW UPSCALE INTO
   CLUSTERS AND LINES WITH AN ATTENDANT GREATER DAMAGING WIND THREAT.

   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 120
   STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH
   NORTHWEST OF RICHMOND VIRGINIA TO 55 MILES SOUTH SOUTHWEST OF
   SOUTH HILL VIRGINIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE
   THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.

 

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Once again, mesoscale modela are having trouble and struggling with convective trends and initiation. The HRRR was horrendous last night with the convective explosion last night across the Eastern Carolinas. Likewise the 4KM NAM this afternoon overblown convection. Atmosphere in Eastern SC still needs recovery time from last night and trends indicate, the best chances will likely be another nocturnal explosion with some subtle nocturnal low level jetting.

Yesterday afternoon, despite 5500 j/kg in the area, mid level capping just shunted any growth within 30 minutes. Despite that, nocturnal CAPES will continue to be elevated and the atmosphere will be primed for that spark.

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That cell near Durham is nasty, getting that look like it wants to rotate on the western end too.....I am guessing Widremann is getting it pretty good right now....and that discete super cell in south central VA is about to go tornado

 

Nice velocities around Hillsborough waiting for storm reports had to be some hail/wind damage around there

 

also what a weird shaped warning box left out the MHX counties

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That cell near Durham is nasty, getting that look like it wants to rotate on the western end too.....I am guessing Widremann is getting it pretty good right now....and that discete super cell in south central VA is about to go tornado

 

Nice velocities around Hillsborough waiting for storm reports had to be some hail/wind damage around there

 

also what a weird shaped warning box left out the MHX counties

Def some rotation with that. Was talking to allan about it earlier. The one up near danville looks really nasty too.

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Def some rotation with that. Was talking to allan about it earlier. The one up near danville looks really nasty too.

 

Mebane down to Hillsborough on 40 right now has to be pretty friggen bad nice hail core about to cross it and I imagine the winds right there are severe level easily....

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That cell near Durham is nasty, getting that look like it wants to rotate on the western end too.....I am guessing Widremann is getting it pretty good right now....and that discete super cell in south central VA is about to go tornado

 

Nice velocities around Hillsborough waiting for storm reports had to be some hail/wind damage around there

 

also what a weird shaped warning box left out the MHX counties

It hasn't made its way down to me yet, but it's getting a little darker down here and I have been hearing rumbles for about 20 minutes now.
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mc57ib.jpg

 

post-8089-0-43630400-1435270581_thumb.pn

 

there fairly broadly in the animation (in the spoiler box) and this image, the moisture parcel moving through.  it doesn't seem to be bringing about a specific amount of convection, i can see why it would be difficult for forecast models.

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Still not here and the lead storm is struggling. The storms behind it look good. The flow is just not conducive for quick movement southward. I suppose that's good for racking up rain totals.

 

Seems that the best stuff is holding to the 35-40 knt and up shear zone and that isn't moving south much ATM.....but the S/W moving southeast should push that stronger shear further south so I am still thinking this is going to end up being a more organized line sometime in the next 3-4 hrs.....that drops SE across most of central and eastern NC the Hi Res all have it.....just need enough forcing to set it off and apparently 35-40+ knts of shear is the ticket....

 

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