Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Topeka Kansas
346 PM CDT Tuesday Aug 4 2015

Short term...(this evening through wednesday)
issued at 336 PM CDT Tuesday Aug 4 2015

Thunderstorms continue to develop along a frontal boundary extending
from near Concordia to Topeka into southern Kansas City at 20z.
Latest measoanalysis shows moisture convergence along the boundary
along with MLCAPE of 1500-2000 j/kg. Aloft a shortwave trough was
moving across north central Kansas aiding in ascent as well as good
moisture transport at 850 mb. Precipitable water values range from
around 1.6 inches along the boundary with higher values across
southern Kansas and Oklahoma advecting northward. Line of storms is
expected to fill in along the boundary from Topeka through the
Lawrence area. Further south expect more scattered storms into the
evening hours. Upper trough over north central Kansas will move east
this evening while a second trough over Wyoming moves east southeast
through the night and then across eastern Nebraska and northern
Kansas on Wednesday. Expect scattered thunderstorms to slowly move
northeastward this evening, then expect storms from the western High
Plains to move southeast in the northwest flow into central Kansas
overnight. Also low level jet will focus high Theta-E air from the
south northward over the boundary and therefore expect an increase
in elevated thunderstorms after 06z. With the middle level trough
moving through on Wednesday precipitation may be ongoing through the
morning and perhaps into the afternoon hours. Shear does increase
through the day on Wednesday to around 35 kts with MUCAPE around
2000 j/kg. If there is enough clearing for atmosphere to recover
could see a few strong to severe storms with hail, heavy rainfall
and damaging wind gusts. Highs on Wednesday should range from the
lower to middle 80s.

Long term...(wednesday night through tuesday)
issued at 336 PM CDT Tuesday Aug 4 2015

Precipitation should diminish Wednesday night from west to east as the upper
system finally departs and middle/upper ridging provides at least a
brief break in the storm chances. That break should occur around
Thursday before the next upper wave in the northwest flow regime
brings another complex of storms to the plains Thursday night. Any
precipitation should be moving off to the east of the area by Friday morning
with another brief break during the day expected before another
mesoscale convective system develops across the High Plains and tracks east-southeast into the area
Friday night and early Saturday. Beyond Sat we remain on the southern
periphery of the westerlies with what has been a semi permanent
low and boundaries across the state so cannot rule out more storm
chances especially later sun into Monday before perhaps we dry out later
Monday into next Tuesday. All in all a very active and wet period for
early August will continue into the weekend and at least early
next week.


Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1250 PM CDT Tuesday Aug 4 2015

Forecast period should be active at times, but not expecting a
total washout over the terminals. Thinking is that later this
afternoon with some heating and additional forcing aloft coupled
with several boundaries over or near the terminals, that a decent
chance for thunderstorms should set up and last until late
evening. The early morning should see a lull in activity and then
by around 10-12z another wave may make its way into the region
which could bring about the chance for more storms which also may
bring ceiling/visible into the IFR category. Have not been that
pessimistic with this issuance. Depending on how actual features
develop and track, then there will likely be some changes to this


Top watches/warnings/advisories...


Short term...53
long term...omitt

National Weather Service Glossary of Abbreviations