Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wichita Kansas
313 am CDT Tuesday may 5 2015
Short term...(today through thursday)
issued at 307 am CDT Tuesday may 5 2015
Lingering showers and thunderstorms continue along a quasi
stationary boundary situated just north of Interstate 70 at this
time. Latest short term hi-res models suggest this boundary will
slowly lift back to the north this morning towards Nebraska...taking most
of the shower activity north with it. This will lead to dry
conditions for the daytime hours across the forecast area...as a
warm elevated mixed layer caps off any precipitation chance with less
instability this afternoon.
The main dryline and convergence for storm chances looks to shift
into western Kansas for this afternoon into this evening. Think showers
and thunderstorms will develop along this dryline and make slow
progress to the east...as an initial shortwave rotates north across
western Kansas late this afternoon.
But expect another more potent shortwave to rotate north out of southern
nm during the evening with this shortwave lifting northeast
across the forecast area for the late evening and overnight hours.
Lift associated with this shortwave will lead to showers initially
developing in OK...with the storms moving north into the area
during the late evening hours. As this impulse moves across the
area...widespread showers and some embedded thunderstorms will
Blossom across most of the forecast area for the overnight hours
as the upper level diffluence increases. Previous shifts adjusted
the pop timing with categorical probability of precipitation mainly after 06z...with
likely probability of precipitation for the evening hours. This looks okay.
Some uncertainty on how early Wednesday will play out...as remnant showers
and embedded thunder will still be across central Kansas for the morning
hours. Lots of remnant cloud cover will also be around...as
instability increases and the dryline pushes east closer to the
forecast area for Wednesday afternoon. If airmass can recover...latest
NAM/WRF and GFS show a very unstable airmass will be in place across
south central Kansas...with deep layer bulk shear increasing to around
30-40 kts. Weakly capped environment will be in place..so expect
discrete storms to develop along this dryline for Wednesday
afternoon....with storms expected to become supercells given the
directional shear. This certainly looks like a severe weather threat
with large hail and damaging winds the main concern.
Dryline is expected to retreat back to the west during the nighttime
hours on Wednesday...so not entirely sure how long the convection will
continue into Wednesday night...as some warmer air aloft will effectively
shut down the convection.
The dryline will again come into play on Thursday...as the boundary
becomes more of a cold front and again pushes into portions of
central Kansas for Thursday afternoon as a northern stream system helps push
it further east.
Instability and shear suggests another round of severe weather may
occur along this boundary for portions of the forecast area for Thursday
afternoon/evening...as supercells will again be possible. Will have
to keep an eye on this severe weather threat...as an area of low
pressure in the OK Panhandle may setup a triple point across south
central Kansas...with surface winds backing across southern Kansas and better low
level turning for a possible increased tornado threat. Stay tuned.
Long term...(friday through monday)
issued at 307 am CDT Tuesday may 5 2015
The active pattern looks to continue for Friday and Sat...as the main
surface boundary becomes stationary across southern Kansas on Friday
afternoon. The middle level baroclinic zone will also remain Colorado-
located with the surface boundary as well....with shower and
thunderstorms expected to redevelop across southern Kansas as the low
level jet increases over the top of the boundary. This has all the
signs of a severe weather producing complex of storms (mcs)
developing late Friday night across southern Kansas...considering the amount of
instability that will be around and bulk shear of 40 kts.
How Sat will play out will depend on where the mesoscale convective system late Friday night
GOES and any outflow boundary it pushes out. Medium range models
suggest that a vigorous shortwave is expected to lift northeast out
of the Southern Plains on Sat evening and will push any kind of
boundary/warm front back north across the area for Sat night...which
will lead to another chance of severe storms for Sat night as well.
Will certainly have to keep an eye on water issues going into the
weekend...as most of the convection will be very effective rainfall
producers for heavy rainfall and possible flooding concerns.
Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 1150 PM CDT Monday may 4 2015
Storms have been a bit slower to exit central Kansas than anticipated...
but short term models are still Adamant that precipitation will
push north early in the forecast. Latest rap is a bit different
keeping outflow/surface boundary quasistationary but still moving
precipitation to the north. This seems plausible based on radar
trends. Focus then turns to timing of convection tomorrow.
Outflow boundary might focus initial updrafts...but inability to
accurately forecast its location precludes an early mention in
tafs. Will stick with higher probability of just prior to 0000
UTC at krsl/khut and after 0000 UTC at ksln/khut. Have kept kcnu
dry for now...but rogue cell could affect kcnu during pk heating.
Preliminary point temps/pops...
Wichita-kict 77 62 77 65 / 10 90 60 40
Hutchinson 76 61 76 63 / 10 90 50 50
Newton 74 60 75 62 / 10 90 60 40
Eldorado 79 62 75 64 / 10 90 70 40
Winfield-kwld 77 63 76 65 / 10 90 60 40
Russell 75 59 78 60 / 40 80 50 50
Great Bend 73 59 78 62 / 50 80 40 40
Salina 78 61 76 65 / 10 90 50 50
McPherson 75 61 75 63 / 10 90 50 50
Coffeyville 78 63 75 65 / 10 80 80 40
Chanute 79 62 75 64 / 10 70 80 30
Iola 78 62 75 64 / 10 70 80 30
Parsons-kppf 79 63 75 65 / 10 70 80 30