Jump to content
  • Member Statistics

    17,609
    Total Members
    7,904
    Most Online
    NH8550
    Newest Member
    NH8550
    Joined

2017 General Severe Weather thread


downeastnc

Recommended Posts

  • Replies 554
  • Created
  • Last Reply

 
SEVERE WEATHER STATEMENT  
NATIONAL WEATHER SERVICE WAKEFIELD VA  
629 PM EDT FRI MAR 31 2017  
  
VAC550-810-312300-  
/O.CON.KAKQ.TO.W.0006.000000T0000Z-170331T2300Z/  
CITY OF CHESAPEAKE VA-CITY OF VIRGINIA BEACH VA-  
629 PM EDT FRI MAR 31 2017  
  
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM EDT FOR ...THE  
NORTHEASTERN CITY OF CHESAPEAKE AND THE CENTRAL CITY OF VIRGINIA  
BEACH...  
      
AT 627 PM EDT, A CONFIRMED LARGE AND EXTREMELY DANGEROUS TORNADO WAS  
LOCATED NEAR PRINCESS ANNE, OR NEAR KEMPSVILLE, MOVING EAST AT 30  
MPH.  
  
THIS IS A PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW!  
  
HAZARD...DAMAGING TORNADO.   
  
SOURCE...LAW ENFORCEMENT CONFIRMED TORNADO. AT 625 PM...A TORNADO   
         WAS REPORTED ON THE GROUND AT INDIAN RIVER ROAD AND ELBOW   
         ROAD.  
  

Link to comment
Share on other sites

From the SPC: 

More substantive moisture return and potential for destabilization is evident across parts of the southeast Wednesday into to Wednesday night. However, greatest confidence in a substantive organized severe thunderstorm risk appears across the Mid Atlantic region on Thursday, coinciding with most significant surface cyclone deepening and strengthening of lower/mid tropospheric wind fields. This may include southerly 850 mb flow strengthening to 50-70 kt, contributing to strong to extreme low-level shear supportive of considerable thunderstorm wind damage potential, along with a risk for tornadoes.

Link to comment
Share on other sites

From the SPC:

Amplification within the westerlies across the Pacific coast into the Plains by the middle of this week appears likely to shift eastward through the Atlantic Seaboard by next weekend. Models suggest that this will support the continuing development of a broad deep lower/mid tropospheric cyclone through the Ohio Valley into the Northeast. Rapid substantive moisture return to the warm sector of the cyclone appears possible in the wake of a previous cyclone, initially along a developing warm frontal zone across parts of Alabama and Georgia by early Wednesday, closer to the cyclone center across the Ohio Valley by Wednesday evening, and across the Mid Atlantic Coast region by Thursday. Associated destabilization in the presence of favorable large-scale forcing for ascent and strengthening low-level and deep layer shear is expected to support considerable organized severe weather potential, including evolving storm clusters and discrete supercell activity. Severe wind gusts and tornadoes will be possible with strongest activity, along with a risk for large hail. It seems probable that areas of higher severe probabilities will be required in subsequent outlooks for this time frame.

Link to comment
Share on other sites

MHX is getting worried about the Wednesday Thursday threat with some strong wording.

Some timing
differences remain with exact placement of synoptic features
during this time frame, though it appears that a potentially
widespread severe weather outbreak could affect the region. The
aforementioned trough attains a strong negative tilt as it
swings through the Southeast US and as a result deep rich
moisture gets advected into the region in tandem with very
strong dynamics to support severe thunderstorms. Tremendous
height and pressure falls occur early Thursday as the sfc low
deepens to around 980MB to the north. 03/00Z GFS/CMC/ECM global
suite continue to indicate 850H flow of 50-70 kt aided by 110+
kt 300MB jet, and PW values AOA 1.5". Even if timing of the
severe threat is relegated to Wednesday night and early
Thursday, instability parameters are quite high due to the sharp
height falls yielding steep mid level lapse rates, and sfc TD`s
rising through the 60s overnight Wednesday. Hodographs are
quite troubling in that strong SRH values aoa 400 M2/S2 are fcst
by the NAM/ECMWF with low LCLs present. If all these
ingredients come together the threat for a few strong tornadoes
and strong damaging winds would be present.

 

Link to comment
Share on other sites

4 hours ago, shaggy said:

MHX is getting worried about the Wednesday Thursday threat with some strong wording.

Some timing
differences remain with exact placement of synoptic features
during this time frame, though it appears that a potentially
widespread severe weather outbreak could affect the region. The
aforementioned trough attains a strong negative tilt as it
swings through the Southeast US and as a result deep rich
moisture gets advected into the region in tandem with very
strong dynamics to support severe thunderstorms. Tremendous
height and pressure falls occur early Thursday as the sfc low
deepens to around 980MB to the north. 03/00Z GFS/CMC/ECM global
suite continue to indicate 850H flow of 50-70 kt aided by 110+
kt 300MB jet, and PW values AOA 1.5". Even if timing of the
severe threat is relegated to Wednesday night and early
Thursday, instability parameters are quite high due to the sharp
height falls yielding steep mid level lapse rates, and sfc TD`s
rising through the 60s overnight Wednesday. Hodographs are
quite troubling in that strong SRH values aoa 400 M2/S2 are fcst
by the NAM/ECMWF with low LCLs present. If all these
ingredients come together the threat for a few strong tornadoes
and strong damaging winds would be present.

 

Yeah, we are in an enhanced threat for Wed already!

Link to comment
Share on other sites

Scary, yet kind of exciting...looks like I'm in the middle of Wedsnesday's threat.

 

pBy7Dxa.gif

 

Quote

Day 3 Convective Outlook 
NWS Storm Prediction Center Norman OK
0226 AM CDT Mon Apr 03 2017

Valid 051200Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS WEDNESDAY
ACROSS MUCH OF SOUTHERN AND EASTERN ALABAMA AND THE WESTERN FLORIDA
PANHANDLE THROUGH GEORGIA AND PORTIONS OF WESTERN SOUTH CAROLINA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SURROUNDING
AREAS OF THE SOUTHEAST...NORTHWARD INTO THE OHIO VALLEY...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN AREAS
SURROUNDING THE SLIGHT RISK AREA...

...SUMMARY...
Severe thunderstorms are expected across much of the Southeast,
northward along and west of the Appalachians into the Ohio Valley,
on Wednesday. This will include the risk for storms capable of
producing tornadoes, at least a couple of which may be strong.

...Synopsis...
Amplification within the westerlies emanating from the mid-latitude
Pacific appears likely to gradually translate across and east of the
Rockies during this period. As large-scale ridging builds across
the U.S. Rockies and Canadian Prairies, large-scale downstream
troughing is forecast to continue to evolve from the Plains eastward
into the vicinity of the Appalachians by 12Z Thursday. A lower/mid
tropospheric cyclone associated with an initial significant
perturbation turning northeast of the southern Rockies on Tuesday,
appears likely migrate northeast of the lower central Plains/Ozarks
through the Ohio Valley Wednesday/Wednesday night. Further
deepening of the surface low is expected, with strengthening wind
fields and shear within/above its potentially broad warm sector. 
Low-level moisture will still be in the process of returning, in the
wake of a prior system, and this appears to be the primary
uncertainty at this time which could temper the overall severe
weather potential.

...Southeast...
Greatest confidence in substantive boundary layer moistening appears
across portions of the eastern Gulf states into the south Atlantic
Coast states. Vigorous convective development may be ongoing at 12Z
Wednesday inland of the northeast Gulf coast, in response to
destabilization associated with the moistening, and large-scale
ascent associated with lower/mid-level warm advection. Guidance is
suggestive that this may be aided by forcing associated with a
subtropical speed maximum, which may contribute to an increase in
coverage through the day, within the northeastward advecting
moisture plume. In the presence of at least modestly steep
mid-level lapse rates, and wind profiles becoming characterized by
strong deep layer shear and sizable low-level hodographs,
considerable organized severe weather potential appears to exist. 
This may include discrete supercells accompanied by the risk for
large hail and tornadoes. Severe thunderstorm potential could
continue into Wednesday night across and to the lee of the southern
Appalachians, ahead of the main upper trough.

...Ohio/Tennessee Valleys...
Although a bit more uncertain at this time, models indicate at least
a corridor of substantive pre-frontal low-level moisture return is
probable, in a pre-cold frontal plume across Tennessee into the
vicinity of the surface low center and warm front across the Ohio
Valley. Uncertainties also remain evident concerning the track of
the cyclone, and this is reflected in the delineation of the severe
probabilities. But, in the presence of considerable large-scale
forcing for ascent, and strong deep layer/low-level shear, organized
severe storm development still seems possible over a fairly broad
area. This includes the risk for discrete supercells, particularly
late Wednesday afternoon into Wednesday evening.

 

Link to comment
Share on other sites

From the SPC:

Within the warm sector of the cyclone, there still appears a window of opportunity for organized severe storm development on Thursday (mainly prior to 18-20Z), as the exit region of a forecast 90+ kt cyclonic 500 mb jet noses across the Mid Atlantic Coast region. Models suggest coinciding strengthening of a southerly 850 mb jet in excess of 50 kt across this region, as increasing surface dew points, and insolation beneath a dry slot, contribute to at least weak boundary layer destabilization. There appears potential for discrete supercell development, and perhaps an evolving line of storms, with potential for severe hail, damaging straight-line wind gusts and a few tornadoes, before upper forcing and the moistening warm sector shift offshore late Thursday afternoon.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...