STORM2K

Is not common to see a 30% latched to a 6 day forecast and that could mean a big event upcoming.Let's see what happens.

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0323 AM CDT Sun Apr 23 2017

Valid 261200Z - 011200Z

...DISCUSSION...
...Wednesday/Day 4...
The ECMWF and GFS solutions are in good agreement on Wednesday/Day
4, moving an upper-level trough across the southern and central
Plains. At the surface, a cold front is forecast to move into the
mid Mississippi Valley. Strong to severe thunderstorms are expected
to develop along the front from central Arkansas into southeast
Missouri during the late afternoon and early evening.

...Thursday/Day 5...
The ECMWF and GFS solutions move the cold front into the central
Appalachians extending back southwestward into the Tennessee Valley.
A marginal severe threat will be possible along parts of the front
Thursday afternoon.

...Friday/Day 6...
The ECMWF and GFS solutions are in better agreement for Friday/Day
6, moving an upper-level low in the Four Corners region as a
mid-level jet rounds the base of the system. Strong moisture
advection is forecast to take place in the southern Plains where
both solutions show a well-developed dryline by late afternoon. As
the exit region of the mid-level jet moves out into the southern and
central Plains late Friday afternoon, thunderstorms should develop
along the dryline and move eastward across parts of Kansas and
Oklahoma. The mid-level jet is forecast to couple with the low-level
jet creating deep-shear profiles favorable for supercells,
tornadoes, large hail and damaging wind gusts. A higher-end severe
weather event could occur Friday afternoon and evening in the
southern and central Plains. For this reason, have added a 30
percent contour inside the original 15 percent contour.

...Saturday/Day 7...
The medium-range models move the upper-level system across the
central Rockies on Saturday/Day 7 as the mid-level jet core ejects
northeastward across the southern and central Plains. Thunderstorms
are expected to develop across much of the region due to strong
large-scale ascent associated with the upper-level trough. This
along with moderate instability and strong deep-layer shear should
be enough for a severe weather event across parts of the southern
and central Plains, where a 15 percent contour has been added.

...Sunday/Day 8...
The medium-range models move a cold front into the mid Mississippi
Valley on Sunday/Day 8 as an upper-level trough moves into the Great
Plains. A severe threat may develop across parts of the cold front
Sunday afternoon but predictability remains low this far out in the
day 4 to 8 period.

..Broyles.. 04/23/2017

Yes, very impressive indeed ESP for areas just north of DFW. Red River valley region and points northward. Could be one of the bigger events in several years. Nearly all Ensemble members are onboard with this . Def needs to be closely watched in the coming days.

very much agree with the above sentiment. long range signals/calendar/geographic location is the trifecta I look for.

 https://twitter.com/MJVentrice/status/856235834164600833

Models continue to forecast some remarkable looking hodographs in Oklahoma. We will have see if everything comes together, but Friday continues to look like a significant severe weather day.

I'm planning on being out Friday and Saturday. Friday is the obvious day at this point, but I'm also starting to warm up to Saturday in Texas too. A slowish trough ejection should maintain an impressive warm sector across the state, and I like the secondary surface cyclogenesis as currently modeled in the Big Bend area Saturday afternoon.

First time I've seen a 30% since I got into storms hope people stay Weather aware.

Fingers crossed for another bust.

WeatherGuesser wrote:Fingers crossed for another bust.

Seem's like we dodged the worst case scenario so many time's now.

 https://twitter.com/MJVentrice/status/856497960242335751

^^ Blank post.

If you're trying to relay information, copy/paste of the text works better than embedding some sort of script or link.

WeatherGuesser wrote:^^ Blank post.

If you're trying to relay information, copy/paste of the text works better than embedding some sort of script or link.

@MJVentrice Latest forecast of my experimental severe weather index; still some shifting going on with timing but major outbreak possible Apr 28-30



The staff discussed about this topic of Twitter and a portion is as follows:

Most likely twitter is blocked at their office so the posts will not show. A lot of workplaces block image sites as well. If it's a particularly important tweet I will sometimes copy and paste the text in case folks can't see the tweet.

Latest am data from the 6,12z runs of the GFS continues to suggest moisture will be a big problem limiting a potential outbreak on Fri, however the latest Euro run still is locked on a sig severe event across at least a good chunk of Central into South Central OK. This event is far from over it's only Monday!

Yeah , I'm not buying GFS on moisture return yet, it was dreadful handing moisture return on last Friday's system. Either too much, or not enough. Having a hard time believing this strong of a system is only gonna get 50's dewpoints up into OK in late April.

I don't think moisture will be a issue this event the gulf is wide open.

Looks like it might be NAM and Euro vs GFS again. NAM bringing moisture much further north, though we can only see until 7am Friday. 7am NAM has 60+dewpoints on the Oklahoma/Texas border while GFS has the rich moisture confined to South Texas.

0z GFS is now on board again, impressive classic soundings for Central and South OK once again. Seemed like a classic midrange out to lunch trend from the GFS this morning. EURO, GFS and looks like NAM all in pretty decent agreements

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0403 AM CDT Tue Apr 25 2017

Valid 281200Z - 031200Z

...DISCUSSION...
Active severe-weather regime in store for days 4-6 from the southern
Plains into the lower Mississippi and Tennessee Valley regions, with
models trending similar regarding evolution of the upper pattern
during this period.

Friday (day 4) - A lead shortwave trough will shift northeast
through the OH Valley during the day with upstream height rises from
the southern Plains into the TN Valley. Quasi-stationary front will
reside from the TN valley into northern TX with a dryline evolving
across west central or northwest TX where it will intersect the
front. Limited synoptic forcing for ascent and capping due to
eastward expansion of EML may limit thunderstorm initiation during
the day with best chance being at the intersection of dryline and
front over west-central or northwest TX. Large CAPE and strong
vertical shear would favor a conditional risk for supercells with
very large hail and a few tornadoes should such initiation occur.
Farther east thunderstorms including supercells are more probable
during the day near the warm front from the lower MS Valley into the
TN Valley where the cap should be weaker. Other more numerous storms
including supercells with large hail will occur overnight north of
warm front over OK in association with strengthening LLJ.

Saturday (day 5) - Current indications are the upper trough will
amplify over the southern Rockies and continue east through the
southern Plains accompanied by a strong cold front. Numerous severe
storms are expected to develop along this boundary and progress east
through TX and the lower MS Valley where the atmosphere will be
strongly unstable.

Sunday (Day 6) - As the trough and its associated cold front
progress eastward, the severe-storm threat will spread into the TN
Valley and southeast states where favorable vertical shear will
coexist with a moderately unstable warm sector downstream from an
ongoing MCS.

I fully expect late Fri to be a big day on the threshold of a Moderate risk now IMO if some of the finer details could get worked out which we all know might be very last min. Regardless Extreme instability coupled with ample moisture (Dews nearing 70 in some locations) along with strong shear will create a favorable environment for super-cells capable of Tornadoes (Some of which could be strong if not violent IMO) I have noticed A LOT of back and fourth on social media about this event oh it's gonna happen then it's not (People going back and fourth with the models) That said...... Here is some stats for you out of over the last 30+ runs nearly 60+ percent have showed a High-End event. Models go back and fourth but sometimes you just have to read between the lines, the upper level pattern favors a classic outbreak type scenario... I also see A PDS situation after dark for many areas along the Red River valley on either side by about 50-60 mi..

Edit: Just to add 12z Euro pushes things further N back into even Central OK..