River Flood Warning 121, NWS Wichita, KS

Area Forecast Discussion
National Weather Service Wichita KS
319 PM CDT Thu May 23 2019

...Multiple Rounds of Heavy Rain and Severe Weather through the
Weekend...

.SYNOPSIS...
Issued at 258 PM CDT Thu May 23 2019

Thunderstorms with heavy rain, flooding, and severe weather will
continue to threaten the region through the Memorial Day weekend
and possibly all the way into the middle of next week. Given the
recent rains, some significant flash flooding will be possible at
times.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 258 PM CDT Thu May 23 2019

Hand analysis and satellite imagery early this afternoon depict a
surface low/triple point over the TX Panhandle, with a warm front
extending to the east along the KS/OK border. Aloft, an upper low is
spinning over the Great Basin, with an embedded s/w moving through
WRN CO.

Models differ on how far north the warm front will get through this
evening, which will play an important role in the severe weather
hazards. Just south of the warm front is a broad area of low to mid
70s dewpoints. Through this evening, the low-level jet will continue
to increase, leading to increasing WAA and moisture transport. Of
note, blended TPW products show an impressive surge of moisture
riding north through TX at this time and is poised to reach Kansas
by this evening.

The increasing WAA/moisture transport combined with a glancing
influence from the above-mentioned s/w should foster several rounds
of thunderstorms through tonight. Storms that develop over/near the
TX/OK Panhandles may have a tendency to build/propagate ENE along
the northward-advancing warm front. North of the warm front,
thinking the greatest threat will be large hail (with some
significantly large hail possible near the warm front where
instability will be maximized). Near and to the south of the warm
front is where SFC- based convection will be possible. Backed SFC
winds in this area combined with a general veering profile aloft
should support a tornado threat into this evening. Given the low
level shear/helicity forecast, a conditional threat of strong
tornadoes may develop, especially if any discrete or semi-discrete
cells can develop. Watch for meso-updates later if this threat
becomes more likely. At this time, thinking the tornado risk will
be focused over south-central KS.

Regarding the storm mode, shear vectors will tend to be oriented
more parallel with the frontal boundary, likely leading to more of
a tendency for upscale growth with time. However, as the warm
front continues to push north, it may begin to be oriented more SW
to NE, and be oriented a bit more perpendicular to the deep layer
shear. Should this occur, discrete or semi-discrete cells would be
more probable. Regardless of initial storm mode, upscale growth
into multiple clusters/small MCS' seems plausible overnight, with
an increased risk of flash flooding. The Flash Flood Watch was
expanded east some to account for a bit more eastward propagation
of the zone of convection and we'll continue to refine this area
if needed. Given the surge of moisture incoming and interacting
with the frontal boundary in the area, enhanced rainfall
rates/amounts are likely, potentially focused from near Medicine
Lodge up through portions of central /south-central KS. Given the
recent rainfall and wet soils, it won't take much for flash
flooding. The setup could lead to some significant/higher-impact
flash flooding.

The convective evolution through tonight will play an important role
in tomorrow's thunderstorm/severe threat. Favorable deep layer shear
combined with modest instability within the frontal zone could favor
some strong to severe storms, although the threat may tend to be
more conditional based on early-day convection. Temperatures were
cooled some on Friday as tonight's convection may tend to limit how
much heating can occur.

On Saturday, a stronger s/w is forecast to cross the region with a
renewed potential of strong to severe thunderstorms and heavy rain.
It could be that convection forms on the High Plains, then pushes
E/SE across the area. We'll continue to refine the severe potential
in the coming days.

Martin

.LONG TERM...(Sunday through Thursday)
Issued at 258 PM CDT Thu May 23 2019

Beyond Saturday, SW flow aloft will continue across the Plains with
embedded shortwaves traversing the area with a continued risk of
thunderstorms and heavy rainfall. Each wave will be able to tap into
an unstable and very moist environment, which will likely keep a
continued risk of flooding and severe weather going through at least
early next week. A stronger s/w may finally push through Tuesday or
Wednesday with at least a temporary break in the active weather. The
main takeaway here is the active pattern continues and flooding will
only worsen, with not much of a break in the rain.

Martin

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1253 PM CDT Thu May 23 2019

Expect MVFR cigs to linger over most of the area for the next 12 to
24 hours.  Copious amounts of low level moisture will continue to
funnel north across the area.  As this moisture lifts north, SHRA
and TSRA are expected to develop late this afternoon into this
evening. Expect the showers and storms to become numerous for areas
west of the KS Turnpike, with some MVFR vsbys in and near the
heavier storms.  Plan on keeping the scattered showers and storms
going for all the tafs (except KCNU), throughout most of the
overnight hours, with the TSRA coming to an end by Fri morning.

Ketcham

&&

.HYDROLOGY...
Issued at 258 PM CDT Thu May 23 2019

A heightened flash flood risk may develop this evening through the
overnight hours as multiple rounds of thunderstorms move over the
same general area. There is still some uncertainty regarding the
convective evolution, but given the recent rains, wet soils, and
high moisture content, the potential of very efficient rainfall
exists. Where storms train over the same area, we could be looking
at 3-5"+. If storms end up more progressive, the amounts could be
lower overall. But, with very low flash flood guidance, it won't
take much to cause flooding. Aside from the flash flood threat,
river flooding will continue to be a significant and long-lasting
threat well into next week.

Martin

&&

.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT    65  75  67  81 /  90  70  50  30
Hutchinson      62  75  66  81 /  90  40  50  30
Newton          64  75  67  81 /  90  60  50  30
ElDorado        66  76  69  80 /  80  70  50  30
Winfield-KWLD   67  78  69  80 /  80  80  40  30
Russell         55  77  64  82 /  80  20  40  20
Great Bend      56  77  64  82 /  80  30  30  30
Salina          62  77  66  83 /  90  40  60  30
McPherson       61  76  66  81 /  90  40  60  30
Coffeyville     71  83  69  82 /  10  30  20  20
Chanute         70  81  69  81 /  30  40  30  40
Iola            70  81  69  81 /  40  50  40  40
Parsons-KPPF    71  82  69  82 /  30  30  30  30

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Saturday morning for KSZ032-033-
047>053-067>070-082-083-091>093.

&&

SYNOPSIS...RM
SHORT TERM...RM
LONG TERM...RM
AVIATION...Ketcham
HYDROLOGY...RM

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