Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 181142
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
642 AM CDT Mon Aug 18 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 313 AM CDT MON AUG 18 2014

Short term forecast is difficult at best as models having difficulty
resolving past nights convection.  Mesohigh has developed under
decaying showers over eastern Kansas at this hour, pushing the
effective front southward into Oklahoma as well as to the west and
north.  Additional shortwave trofs noted in WV imagery over NW KS
and Nebraska into the Dakotas, and these are likely to influence
weather later on in the day.

Trimmed back morning PoPs to isolated and diminished west to east
not long after sunrise. Forecast is based largely on mesoscale
effects of the convection,and have delayed onset of another round of
convection until the late afternoon hours after atmosphere has a
chance to destabilize once again. Models ramp up instability given
high dewpoints and steeper mid level lapse rates but a weak cap
remains in place most areas. Shear values also borderline around
30-35kts. With lack of a strong wave may be a case of storms back
building into our area or low level jet dynamics generating storms
later on.  Will have to watch how pattern unfolds after tonights
convection, but at this time think chances may be better to the
northeast where front and energy are more juxtaposed later today. Highs
today from near 90 NE top near 100 in the southwest. Expect warm
overnight lows near 70.

.LONG TERM...(Tuesday through Sunday)
Issued at 313 AM CDT MON AUG 18 2014

On Tuesday morning the front should be stalled out along or just
south of interstate 70, and extend west through north central KS.
Depending on the strength of the frontogenesis during this time
frame have kept slight pops across the southeast forecast area. The
front is forecast to lift northward into NE and northwest MO during
the day Tuesday as the strong upper low continues further east into
the Great Lakes region. Lift should increase overnight north of the
front although the precip may develop near the NE/KS state line
before it moves north. On Wednesday the upper ridge really begins to
build across the Mid South keeping the forecast area within the warm
sector. A shortwave moving northeast through the northern plains
will push a front through western KS Wednesday night. As the ridge
holds strong over the south so does the front out west. The models
suggest weak shortwaves embedded within the southwest flow aloft
moving over the frontal boundary in western KS and NE through late
week. Have kept the slight chances for thunderstorms in north
central KS in case anything that develops along that front and moves
eastward especially Thursday night and Friday night. As a strong
upper low moves through southern Canada it begins to suppress the
ridge over the weekend. Depending on how far south the ridge gets
suppressed will dictate the front moving into eastern KS and the
better chances at some precip. Until then high temperatures will
remain in the 90s and low 100s in central KS through late week. Not
much relief overnight with lows in the mid to upper 70s.

&&

.AVIATION...(For the 12Z TAFs through 12Z Tuesday Morning)
Issued at 641 AM CDT MON AUG 18 2014

TAF is VFR through the period, although there are chances for
thunderstorms in the latter 12 hours. Will hold off on any
vicinity until forecast becomes more defined as there is
considerable spread in coverage and timing of convection that may
form.

&&

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

$$

SHORT TERM...67
LONG TERM...Sanders
AVIATION...67






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