Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KTOP 280823
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
323 AM CDT FRI AUG 28 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 249 AM CDT FRI AUG 28 2015

Early this morning an upper trough extended from northwest IA
southwest across central KS. Ascent ahead of the trough axis
combined with isentropic lift above 850mb level was causing numerous
showers and isolated thunderstorms across the western and northern
counties of the CWA. MUCAPES were only around 500 J/KG, thus the
elevated thunderstorms will remain rather weak through the morning
hours. The scattered to numerous showers along with isolated
elevated thunderstorms will continue to move east across northeast
and east central KS through the morning hours. We may see a break in
the showers and thunderstorms during the early afternoon hours as
the stronger isentropic lift shifts northeast into northern MO and
eastern IA.

A second H5 trough will dig southeast across eastern KS later this
afternoon along with a surface cold front located across central NE
and northwest KS. As the surface front pushes southeast across
northeast and east central KS, scattered showers and thunderstorms
will develop along the surface front. There may even be some post
frontal showers and thunderstorms due to the stronger ascent ahead
of the H5 trough digging southeast on the back side of a developing
closed upper low across northeast IA and southeast MN.

If we see some insolation then MLCAPES may increase to around 1500
J/KG. The sfc to 6 KM effective shear will remain rather weak, under
20 KTS, through the day as the low-level flow veer to the southwest
ahead of the surface cold front. There could be a few strong storms
that may produce small hail and gusty winds if the atmosphere
destabilizes ahead of the surface front. The surface front and H5
trough will pass southeast of the CWA after 6Z. There could be a few
lingering showers northwest of the front across the extreme southeast
counties through the early morning hours of Saturday but these
showers should shift southeast of the CWA before 12Z SAT.

Highs Today will be dependent on the degree of insolation. If we
remain cloudy through the day then highs may only reach the upper
70s to lower 80s. Areas that see more insolation may reach the mid
80s. Tonight lows will drop into the lower to mid 60s.

.LONG TERM...(Saturday THROUGH Thursday)
ISSUED AT 249 AM CDT FRI AUG 28 2015

Saturday...Weak shortwave trough drifts slowly off to the
southeast, ending precip chances in east central KS, although some
clouds could linger in that area through Saturday night.

Saturday night through Sunday night...Upper ridge builds east
during this time as previously mentioned remnant vort max weakens
over the Ozark area. Would expect dry conditions through this time
period...although isolated showers could form in southeast KS,
with a small chance they could affect areas mainly south of I35.

Monday through Tuesday night...Upper ridge is flattened by a
shortwave trough that moves from the central Rockies to the Upper
Midwest. Main dynamics/lift with this trough should be to our
north but both GFS and ECMWF do develop QPF in north central/far
northeast KS Tuesday night. Have added low POPS for that area
overnight.

Wednesday through Thursday...Behind this trough, persistent low-
level warm advection helps build upper ridge back over the eastern
Plains into the Upper Midwest, with seasonably warm max
temperatures expected to be in the lower 90s each day.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Friday NIGHT)
ISSUED AT 1152 PM CDT THU AUG 27 2015

Area of showers and thunderstorms over north central KS late this
evening should move east through northeast Kansas through Friday
morning. Preferred the latest HRRR and 00Z 12KM NAM concerning
the movement of the precipitation. Given the limited instability,
precipitation will likely be showers with embedded thunderstorms
so forecasted showers at KTOP/KFOE. 00z NAM sounding for Friday
afternoon suggest surface based thunderstorms are possible as weak
boundary approaches. Kept VCTS for this possibility. Otherwise,
VFR conditions.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Gargan
LONG TERM...GDP
AVIATION...Johnson



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.