Area Forecast Discussion
Issued by NWS Topeka, KS

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488
FXUS63 KTOP 230822
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
322 AM CDT THU JUN 23 2016

.SHORT TERM...(Today and Tonight)
Issued at 320 AM CDT THU JUN 23 2016

Upper flow over the local area remains weak but westerly with upper
high over the Southern Plains and quick zonal flow persisting over
the northern states. Weak frontal boundary was from near Kansas City
into south central Kansas with little movement in recent hours.
Convective system over southwest Kansas appears to be weakening per
IR and VIL trends though at least one MCV was nearby, moving east to
northeast.

Models are consistent with previous runs and each other on larger
scale with surface pressures falling just east of Northern Rockies
today and front mixing back north in the afternoon and nighttime
hours. How these trends impact precipitation chances through these
periods is the main challenge. Initial MCV could stay to the south,
keeping most precip with it just south of the local area, but will
keep some late morning to afternoon chances in southern and
southwestern areas. Instability near the front will likely be
increasing in the afternoon, with the potential for little
inhibition in the absence of clouds/precip, though shear will
continue to be rather weak with modest mid/upper level winds. Storms
that would form along the front in the afternoon and evening could
be briefly strong to severe with downburst winds and hail near 1"
the main concerns. Perhaps the greater concern is heavy rain
potential as the front is slow moving and a weak but increasing low
level jet develops overnight. Again with weak steering flow, CAPEs
of the skinny variety, and well-above normal PW values near 2",
ingredients are in place for at least locally heavy rain, but with
early-day convective chances, very warm troposphere still largely in
place keeping RH values from being very high, and the continued lack
of high model QPF from any operational or ensemble model, confidence
is low and have kept chance pops going. Temps still look to be
notably cooler than Wednesday with 850mb values several degrees
cooler.


.LONG TERM...(Friday through Wednesday)
Issued at 320 AM CDT THU JUN 23 2016

By Friday, a broad mid-level ridge will still be in place across the
southern conus with a mid-level low moving into the Pacific
Northwest.  Models show the cold front over southeast KS Thursday
night lifting northward across the area as a warm front. This front
in conjunction with a passing mid-level shortwave should help to
produce some scattered showers and thunderstorms Friday into Friday
evening. Decent instability should be in place with 2500-3500+ J/kg
of MUCAPE. Cannot rule out the potential for a few strong storms
across northeast Kansas Friday afternoon into early evening as 0-6km
bulk shear values may be upwards of 25-30kts. The main hazards with
any strong storms would be hail and perhaps some gusty winds. The
combination of southerly winds and partly to mostly cloudy skies
should keep highs in the low/mid 90s.

Models show the mid-level low over the Pacific Northwest advancing
into the northern Rockies by Saturday morning and progressing into
the Dakotas by Saturday night. This advancing trough will help to
push another area of low pressure and associated cold front eastward
into Kansas throughout the day, with models showing the boundary
extending into north central Kansas by late afternoon and bisecting
the CWA overnight. As a result, the forecast area will be in warm
sector all day, with breezy southerly winds helping to boost high
temperatures into the mid/upper 90s.  Some scattered showers and
thunderstorms may develop along and ahead of this boundary, moving
into north central Kansas by mid to late afternoon. Models suggest
that there may be some modest instability in the warm sector ahead
of the advancing front to possibly support some strong storms across
the outlook area late Saturday afternoon into early evening.
However, one limiting factor is the weak 0-6km shear of only 20-
25kts.  If any strong storms are able to develop, the main hazards
would be hail and gusty winds. These showers and storms will advance
eastward across the CWA overnight into Sunday morning as the front
slowly shifts eastward, however expect these storms to become more
elevated overnight. Lingering storms over east central Kansas should
diminish through the day on Sunday.

Once again, models show this cold front lifting northward across the
forecast area as a warm front Sunday night into Monday morning
before stalling out over the area on Monday. This stalled front
combined with a few embedded shortwaves will help to bring
additional chances for scattered showers and storms early next week.
As surface high pressure digs southward into the area Monday night
into Tuesday, it will help to push the boundary south of the CWA.
However, thunderstorm chances will persist Tuesday into Wednesday as
models show the potential for additional embedded shortwaves to
track near the area.  However, there is still uncertainty in the
exact timing and tracking of these waves during the first half of
next week.  Expect some cooler conditions Tuesday and Wednesday as
highs drop into the 80s/near 90 degrees.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1130 PM CDT WED JUN 22 2016

Will be able to keep TAF fcst short and VFR. Next chance for
thunder comes very late in the period and may not yet be as far
north as the terminals by 24/06z.


&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Hennecke
AVIATION...67



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