Jump to content
  • Member Statistics

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

6/19-6/23 Severe Weather Risk


Jim Martin

Recommended Posts

  • Replies 1.3k
  • Created
  • Last Reply

We noted the lack of mention of the severe threat in the afternoon AFD and an update has been posted this evening along with our weather story graphic. The afternoon guidance was quite concerning.

Sent from my SM-G935V using Tapatalk

 

Good stuff.

Link to comment
Share on other sites

We noted the lack of mention of the severe threat in the afternoon AFD and an update has been posted this evening along with our weather story graphic. The afternoon guidance was quite concerning.

Sent from my SM-G935V using Tapatalk

 

 

noice  :)

Link to comment
Share on other sites

Amazing write up. Highlighted all the concerns and parameters working in favor of a sig severe wx event. I do for see morning convection persisting but I'm confident in some clearing occurring to the south of this. Outflow should really enhance the warm front. With strong capping building north and strong directional and speed shear, I think a discrete mode at first is a good bet. Man if any cell latches onto wf or ofb and is discrete we could have a significant tornado. Incredible shear/cape combo for June

Link to comment
Share on other sites

ILN thoughts.

 

Area Forecast Discussion
National Weather Service Wilmington OH
800 PM EDT MON JUN 20 2016



.LONG TERM /WEDNESDAY THROUGH MONDAY/...
An active convective period is expected Wednesday into Thursday. A
northwest-southeast oriented warm front will initially stretch from
northwest Iowa to southwest Kentucky Wednesday morning. This front
will lift northeast through the day, reaching the ILN forecast area
by Wednesday evening and becoming more diffuse as it lifts into
northeast Ohio Wednesday night. Meanwhile a developing surface low
will track east from the Plains into the southern Great Lakes.
Northwest flow aloft will bring a ripple of weak H5 shortwaves and
PVA through the region, parallel to the warm front, enhancing the
synoptic lift during this period.

Anomalously high moisture will be in place with PWATs increasing to
1.8 to 2.0 inches by Wednesday evening (2-3 standard deviations
above normal). The atmosphere will become very unstable south of the
front during the day, with the ILN forecast area progged to be on
the northern edge of this instability gradient. In addition, bulk
shear will be very impressive for this time of year with 0-6km
values around 50-60 knots, supportive for organized storms. Needless
to say, the ingredients are coming into place for a potentially
significant MCS across the region, with a good chance for it
affecting the ILN CWA.

This far out, there is lower confidence in timing, storm hazards,
and impacted locations. Models continue to show a muddled QPF field
and are struggling to some extent with convective feedback from
elevated activity to our west Tuesday night. The 20.12Z NAM in
particular has shown the greatest run-to-run change, shifting a bit
more northeast. Leaned more on the GFS/ECMWF and ensembles for this
forecast given their better consistency. Isolated/scattered activity
will be possible along the front during the morning, but the best
chance for strong to severe storms impacting the ILN CWA will come
in the later afternoon and evening timeframe when surface based
instability will be highest. All storm hazards (gusty winds, large
hail, flash flooding, and perhaps an isolated tornado) will be in
play given the instability, impressive shear/hodographs, and frontal
boundary in place. Showers and storms will continue Wednesday night
into Thursday as a strong 850mb 40-50+ knot LLJ (2-4 standard
deviations above normal) develops. Given ~2 inch PWATs, deep warm
cloud layers, tall/skinny CAPE, and very strong moisture transport,
resultant training of heavy rain over the same areas may lead to
flash flooding if multiple cells generate and merge along the
boundary Wednesday into Wednesday night.

A cold front will push through the southern CWA on Thursday with
precip chances tapering off behind it. High pressure at the surface
and aloft will provide a dry and mostly sunny period Friday and
Saturday. Upper ridge axis will push east on Sunday, with upper
trough and cold front bringing the next chance for precip Sunday
into Monday. Temperatures will generally remain above normal through
the period.

Link to comment
Share on other sites

Given the WNW flow in the mid levels, even in places where the sfc winds are more southerly or south-southwest still yields a lot of curvature.  Storm mode is a question but even in a linear mess, there could be a pretty substantial risk of spinups.

Link to comment
Share on other sites

Here's the mesoanalysis from around noon on 6/12/13 from the thread in this sub.  The 12-13C isotherm is about the southern extent of the action on this day FWIW.  

 

http://www.americanwx.com/bb/index.php/topic/40472-severe-threat-june-11-13/page-17

 

+12 is pretty common rule of thumb temp, though every set up is different. 

Link to comment
Share on other sites

Yeah the potential would last long after dark with this one. Soundings are uncapped all the way to Ohio by morning.

 

If anything the models got more impressive with the overnight parameters since my shift ended early this morning.

 

18z NAM ripping > -7 C/km theta-e lapse rates after midnight with 70 knot winds aloft.

Link to comment
Share on other sites

Gut feeling is that the activity earlier in the day will make them reluctant to upgrade yet, but who knows.

 

Most likely punt formation until the murky waters clear up.

 

I mean has anything really changed that could push them one way or another from last night (other than some run to run consistency)? 

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...