Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 272339
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
639 PM CDT FRI MAY 27 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Saturday)
Issued at 302 PM CDT FRI MAY 27 2016

An intense upper level trough was located across western KS and
extended southward across the TX PNHDL. This upper level trough will
lift northeast across KS later Tonight. At the surface an area low
pressure was located north of Garden City and will move northeast
into southeast NE by 15Z Monday. A surface front extended southward
across southwest KS into the northern TX PNHDL. A dryline was
located ahead of the front across south central KS, southward across
western OK. Severe thunderstorms have already developed south of ICT
and were moving north-northeast and will probably move into the
southwest counties of the CWA after 5 PM. Additional thunderstorms
will develop within the warm sector as stronger ascent lifts
northeast across eastern KS ahead of the upper level trough.

MLCAPE this afternoon across the CWA were only around 1,000 J/KG due
to the cloud cover and outflow left from last night`s storms. Some
partial clearing across the southwest counties may help the MLCAPEs
increase to near 2000 J/KG by 600 PM. The best chance for severe
thunderstorms will be across the southwest and south central
counties of the CWA. The primary hazard will be large hail and
damaging wind gusts. The 0-6KM effective shear is forecasted to
increase to 40-50 KTS across the western counties of the CWA through
the evening hours. The 0-1KM SRH increases to 50 J/KG across the
western counties of the CWA during the early evening hours. Given
the low 0-1 KM SRH values the chance for any weak isolated tornadoes
will be very small from discrete cells.

The biggest threat with storms this evening and tonight will be
heavy rainfall. There may be prolong periods of training
thunderstorms, especially across the western half of the CWA through
the evening hours. The line of storms will gradually spread east
across the remainder of the CWA during the evening hours. I would
not be surprised if some areas of the CWA see 1 to 2 inches of
rainfall over night. If the line of thunderstorms weaken through the
mid and late evening hours the potential for heavy rainfall may
decrease slightly across the eastern counties of the CWA. We will
have to monitor mesoscale developments to determine the total amount
of rainfall across the CWA through the evening hours.

Given that the ground is saturated and most rivers are at or out of
their banks, any additional heavy rainfall will cause flash
flooding. Therefore I have kept the flash flood watch going through
12Z Saturday.

Saturday, the upper level trough will lift northeast into the  upper
midwest. A secondary front will push southeast into northeast KS
late Saturday afternoon. There may be enough residual moisture for
scattered shower and thunderstorms late Saturday afternoon across
the northeast counties. Highs on Saturday will the upper 70s to
lower 80s with more insolation during the afternoon.

.LONG TERM...(Saturday Night through Friday)
Issued at 302 PM CDT FRI MAY 27 2016

On Saturday, the mid-level trough and surface low will finally lift
northeast of the area. Models seem to be tracking faster with the
this system exiting the area, so expect diminishing showers and
thunderstorms from west to east through the day. In fact, the
ECMWF/NAM/GEM have most of the forecast area dry by the afternoon
with the GFS being the outlier in keeping some scattered
precipitation across eastern KS. If storms are able to clear out
during the morning, then the potential for any stronger storms
should be relatively low.  Due to some uncertainty in the amount of
destabilization present during the morning and how much wind shear
will be in place, cannot entirely rule out the potential for an
isolated strong storm across extreme eastern Kansas. However, the
better potential for stronger storms is looking to be just east of
the forecast area due to the faster tracking of this system.  With
the morning cloud cover, conditions may initially be slow to warm-
up, but expect afternoon temperatures to reach into the upper 70s to
low 80s.

A brief window of dry conditions are looking more likely during the
Saturday night through Sunday morning timeframe before the next mid-
level wave lifts northeastward into the area, helping to push a
boundary northward into at least southern Kansas. As a result,
showers and thunderstorms are expected to develop across the area
Sunday afternoon into Sunday evening.  With the shortwave tracking
overhead through the day on Monday, additional showers and
thunderstorms will be possible.  For any storms that develop Sunday
through Monday, wind shear looks to be minimal, thus limiting the
potential for any strong to severe storms at this time. However,
flash flooding and river flooding will continue to be a concern due
to the heavy rainfall that has already occurred across the outlook
area this past week.  As for temperatures Sunday and Monday, expect
mild conditions Sunday ahead of the advancing wave, pushing high
temperatures into the low/mid 80s.  With ongoing precipitation on
Monday, temperatures should be a bit cooler in the upper 70s to low
80s.

For the extended forecast period covering mid to late next week,
have kept chance POPs in the forecast considering the GFS and ECMWF
are split on intensity and amplification of an upper level trough
pushing across the Northern Rockies into the Upper Midwest Tuesday
and Wednesday.  GFS is much more aggressive with moisture and the
upper level forcing making for a more widespread wet pattern for
Tuesday and Wednesday.  Could see some severe potential slip into
portions of northeast KS if the GFS does verify.  But the ECMWF
would lean more toward a disorganized multicell type set up with
more isolated activity at least the way it looks right now. Forcing,
although somewhat disorganized from both solutions and further north
of the forecast area, will likely see a fairly strong cold front for
this time of year get pushed through the region overnight Wednesday
into Thursday bringing a dry set up for at least a couple days.
Guidance diverges from each other a bit more from here as more upper
level energy resides to the north of the Central Plains with a
modified Canadian high in place with somewhat limited moisture
return into the Friday time frame.  The GFS develops an upper level
cut off low regime over the region which could complicate the
general precipitation forecast depending on how much moisture is
wrapped around late in forecast period on Friday. High temps
through the period should remain generally in the mid to upper 70s
and cool back as low as the upper 50s with the cold front moving
through the area Wednesday night.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 637 PM CDT FRI MAY 27 2016

A line of showers and thunderstorms will move east across the
terminals through 04Z. Visibilities and ceilings will be reduced
to MVFR within the line of storms. VCTS may last through 6Z. Winds
will switch to the southwest after 14Z.

&&

.TOP Watches/Warnings/Advisories...
Flash Flood Watch through Saturday morning for KSZ008>012-
020>024-026-034>040-054>056-058-059.

&&

$$

SHORT TERM...Gargan
LONG TERM...Drake/Hennecke
AVIATION...Gargan



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