Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 061959
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
259 PM CDT Wed May 6 2015
Issued at 258 PM CDT WED MAY 6 2015
Mid level trough currently negatively tilted over the Central Plains
is moving through the area, and is responsible for the scattered
showers that have formed over the forecast area this afternoon.
Radar trends indicate that the most likely corridor for thunderstorm
activity extends from EC Kansas, in Franklin/Miami Counties,
northward toward northern Missouri. This should spell the end of the
rain chances for the evening for eastern Kansas and northern
Missouri. With convection ongoing across Central Kansas, mainly
north central Kansas, there is a reasonable expectation that this
convection will persist into eastern Kansas and eventually into
northwestern Missouri later tonight. Expect this round of storms to
persist well into Thursday morning, but overall should bring a lull
in the precipitation action through the morning and afternoon. For
Thursday, precipitation chances move into the area through the day.
Instability through the day on Thursday will be rather high, with
progged ML CAPE values between 1000 and 2000 J/kg, but those values
could drop if cloud cover persists through the warm part of the day.
Should we get some clearing, the chances for severe weather on
Thursday will be a bit higher. Even with the better instability,
wind shear will be on the lower end, with 20 to 30 knots of deep
Friday will see a surface ridge nose its way into the northern part
of the forecast area, causing conditions to be a bit drier along and
north of Interstate 70, with a boundary sagging southward. Neutral
constant pressure heights, with perhaps a slight tendency toward
height rises is anticipated over the area, which will aid in
subsidence over the area. Despite the boundary across the area
convection should hold off through most of the day, before a
shortwave trough, embedded within the persistent SW flow aloft,
moves through the area. This could kick off a round of showers and
thunderstorms late in the day on Friday.
Saturday then brings a day with the warm sector solidly in place
over the forecast area, as the surface warm front races back to the
north. With the lack of any appreciable lifting mechanism it`s
conceivable that Saturday will be dry for the most part, as severe
thunderstorms fire off to the west. These thunderstorms over Central
Kansas will likely slide east with time, and bring a decent round of
heavy rain, and perhaps a wind/hail threat overnight Saturday night
Finally, Sunday will see the departing MCS moving out of the area,
with clouds likely persisting through a good portion of the day.
It`s likely that these clouds will eventually dissipate, allowing
instability to increase through the day. As the dryline/Pacific
front moves east it will likely kick off a round of severe
thunderstorms across eastern Kansas and western Oklahoma. The detail
of how Sunday pans out will need to be ironed out with time, but the
trends in the GFS have been a bit weaker with the wind fields as the
low level pressure features appear to be slightly farther north than
in previous model runs. Aside from the weaker anticipated low level
flow the northern trajectory of the surface and low level features
might cause the winds to be a bit more veered in the low levels.
Either way, there will likely be plenty of instability and shear
across the area to bring a chance for some severe storms, but the
exact severity will need to be ironed out as we approach the event.
By Monday dry air works its way back into the area, effectively
ending chances for rain from west to east through the night on
Monday night. By late in the forecast period return flow will bring
the moisture back into the area, and perhaps around mid week chances
for rain will resume.
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1229 PM CDT WED MAY 6 2015
Afternoon light rain showers are moving out of the area, and should
only pose a hazard to the terminals for a couple more hours. After
that there will be a prolonged lull in the action before showers and
thunderstorms that form out across Central Kansas move east and into
the terminals early Thursday morning. At this point the exact timing
of the rain is uncertain, as is whether the convection will even
reach the terminals in the first place. Otherwise, only anticipating
VFR conditions with persistent gusty south winds.