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Area forecast discussion
National Weather Service Topeka Kansas
356 am CDT Fri Apr 25 2014
Short term...(today and tonight)
issued at 349 am CDT Friday Apr 25 2014
An intense upper level storm system will move on shore across the
western US late this afternoon then move into the Great Basin and
Desert Southwest through tonight.
The southwesterly flow at mid levels will increase across the
central rockies causing a Lee surface trough to deepen across the
central and Southern Plains. This will cause south-southwesterly
winds to increase to 15 to 25 miles per hour with gusts of 35 miles per hour through the
day Friday. The southerly winds along with deeper mixing will help
high temperatures to warm into the upper 70s to lower 80s across the
County Warning Area.
Tonight, deeper Gulf moisture will begin to be transported northeast
on an increasing southwesterly low-level jet. Isentropic lift will
begin to increase across the southern and eastern counties of the
County Warning Area after midnight and isolated elevated thunderstorms may begin to
form around 9z and last into the mid morning hours of Saturday.
However the 6z run of the NAM model now shows the more favorable
isentropic lift developing east of the County Warning Area after 12z. MUCAPES are
forecasted to increase to 500 to 1000 j/kg along and south of I-35.
Effective vertical wind shear above the level of free convection to the el will also
increase to 30 to 35 kts across eastern Kansas by 12z Sat. If elevated
thunderstorms develop late tonight, then some of the elevated
thunderstorms may produce quarter size hail along and south of I-35.
Any elevated thunderstorms north of I-35 that manage to develop
tonight, where the MUCAPE will only be 200-600 j/kg, may produce
Overnight lows will only drop into the lower to mid 50s given
southerly winds and low-level moisture advection through the night.
Long term...(saturday through thursday)
issued at 349 am CDT Friday Apr 25 2014
Some early day convection may linger across southeast portions of
the County Warning Area and will maintain low end pops across the
eastern 1/3 of the cwa in the morning before convection chances
shift off to the east. For the remainder of the day...a
strengthening elevated mixed layer should suppress convective
potential over most of the cwa except in the far western counties
near/just beyond peak heating where highs in the upper 80s and
convergence may be erode/breach capping inversion with isolated
or scattered convection. Otherwise a very warm and breezy day across
the area with highs mainly in the low to middle 80s.
For Saturday night...the main upper level trough will begin to
rotate out into the High Plains of southeast Colorado with another weaker
shortwave moving northeast across the cwa in southwest flow aloft.
This continues to be slightly slower than previous runs...and with
the delay in stronger forcing aloft and retreating dryline to the
west...uncertainty still exists as to how the severe convection that
forms off the dryline late in the day will be sustained as it moves
northeastward towards/into the cwa through the evening/overnight.
Other convection...mainly elevated in association with the weaker
shortwave...should develop overnight as llvl jet also increases.
This convection could pose a large hail threat. Will maintain higher
end chance pops.
The most concentrated and potentially strongest convection appears
to be on Sunday as the main shortwave lobe over southwest
Kansas/northwest OK region at 12z Sunday...lifts northeastward across Kansas
through the day. Moderate instability develops just ahead of the
dry slot across the eastern half of the cwa by midday and bulk
shear dramatically increases west to east as the upper trough and
associated jet lifts out across the area with all modes of severe
weather possible...although severe wind and hail would be primary.
The dry slot spreads further east of the remainder of the cwa into
the evening with rapidly decreasing chances for thunderstorms and
The upper low will pivot eastward slowly and traverse the cwa
through into Monday night and with cooler air and circulation
aloft... could see enough destabilization to warrant the mention
of thunder through the daytime hours Monday. Otherwise will
maintain shower potential through mid week as main upper trough
and then secondary northwest flow shortwaves eventually move
across the area.
After high temps in the 70s on Sunday...will cool highs into mainly
the 60s Monday....then mainly the 50s and lower 60s on through
Thursday. Lows should generally be in the 40s.
Aviation...(for the 06z tafs through 06z Friday night)
issued at 1132 PM CDT Thursday Apr 24 2014
Some patchy fog will affect top and mhk reducing vsbys to MVFR and
have added a tempo through 09-10z. Forecast soundings and new
models indicate that the surface winds will increase as the
surface high pressure ridge slides southeast. Foe has already come
around to the southwest. Winds will increase after 14z Friday into
the 12-14kt range with gusts up to 22 kts, winds will then back to
the south and decrease to around 10 kts after 01z Sat.