Area Forecast Discussion
Issued by NWS Topeka, KS
FXUS63 KTOP 150451
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1151 PM CDT Tue Apr 14 2015
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Wednesday)
Issued at 336 PM CDT TUE APR 14 2015
Broad open upper trough was centered over southwestern Oklahoma
this afternoon. Light rain showers associated with the wave were
reported over northern Oklahoma while radar returns reached as far
north as Greenwood County Kansas, however were not reaching the
ground. The slower progression of the moisture return has lead to
skies being mostly sunny, warmer temps near 70 degrees, and
slightly stronger easterly winds at 10 to 15 mph sustained.
For this evening, a stronger shortwave trough over the inter
mountain west will help lift the weakening upper trough northeast
through tomorrow. Low level saturation may be difficult to achieve
initially and with the slower track of the wave, have centered the
highest chances east of highway 75 from 10 PM through sunrise. Lack
of strong moisture flux will limit qpf amounts generally near or
less than a tenth of an inch. With mostly cloudy skies, and light
rainfall have lows centered near 50 degrees. Over north central
Kansas, lows are cooler in the 40s where conditions remain dry.
Light showers may become more isolated in the morning hours, before
clearing northeast in the wake of another system building over
western Kansas. Most of the afternoon becomes dry with broken low
clouds persisting. Eastern areas where thicker cloud cover resides,
highs in the lower 60s are likely, while further west temps are in
the upper 60s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 336 PM CDT TUE APR 14 2015
Wednesday night through Friday...Some reasonable agreement for this
time frame, although actual timing of precipitation is likely to be
more intermittent than is depicted in the forecast. Does still look
like Wednesday night will be mostly dry as upper shortwave ridge
moves over Eastern Kansas behind the lead shortwave moving into the
Upper Midwest. Anticipate precip will redevelop as upper trof over
the four corners moves slowly east and possibly shifts slightly
south through this period. Do see some instability advected into
the area from the south enough to include thunder in the forecast.
Numbers vary by model, but with modest instability and shear, still
think severe threat is on the low side this far north of the low.
Highs run from the 60s north to low 70s southeast and lows in the
40s to near 50.
Friday night thru Sunday, the closed upper level low over the four
corners region is slow to lift East to northeast until the main
branch of the polar front jet can amplify overnight Saturday into
the day on Sunday. With no real strong advection in place,
precipitation chances are limited, but will be on and off throughout
the period as some weak energy will rotate around the associated
upper level low as it does begin to lift into the area.
Sunday night thru Tuesday night, the upper level low fully
transitions into an open wave before becoming merged into the longer
wave trough and both lift completely out of the area bringing the
rain chances to an end after a surface cold front passes through and
leaving subsidence in its wake. Generally pleasant conditions will
return for the beginning of the week. However, as the polar front
closed system remains over the Hudson Bay area, it is possible a
weak shortwave may bring a small chance of isolated rainshowers to
the forecast area into the day Tuesday.
Early in the period, temperatures remain pleasant overall and in the
60s due to cloud cover and any associated rain before climbing back
to possibly lower 70s into Monday afternoon with more sunshine. Due
to the cold front, lows dip into the mid 40s for Sunday night but
otherwise generally expect low 50s to be the norm.
.AVIATION...(For the 06Z TAFs through 06Z Wednesday Night)
Issued at 1147 PM CDT TUE APR 14 2015
Low level moisture will move into northern Kansas around sunrise
on Wednesday. Expect this to result in MVFR cigs at TAF sites
beginning in the 11Z to 14Z time frame and lasting through the
rest of the TAF period. Also expect scattered rain showers to
develop, with the main focus between 08Z and 16Z, and the best
chance at TOP/FOE with lower chances at MHK. Cigs should remain
above 2000 feet for the most part, but could see periods of
slightly lower ceiling heights, especially late morning and again