Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Graphics & Text | 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 222309
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
609 PM CDT FRI JUL 22 2016

...AVIATION UPDATE...

.SHORT TERM...(This Evening through Saturday)
Issued at 258 PM CDT FRI JUL 22 2016

A weak mid level shortwave is currently moving eastward over
northern KS and southern NE. The lift provided by the wave and the
monsoonal moisture aloft is supporting an area of scattered showers
and storms. Latest analysis suggests that there is about 1000-1500
j/kg of elevated cape available for these storms. Vertical wind
shear is relatively low, which should limit organized severe
threats. Given the hot temperatures and modest mid level lapse rates
hail should not be an issue. Although wind gusts could be an issue
this afternoon as storms move into an environment with steep low
level lapse rates and dry conditions through a deep layer. Therefore
an isolated strong wind gusts could be possible with the strongest
storm cells. The downdraft cape decreases over northeast KS limiting
the threat there due to an outflow boundary from previous storms
across northern MO. The better chances for showers and storms will
be locations along and north of I-70. The models are not resolving
the mid level wave well so it is uncertain how far southeast the
precip will spread into eastern KS. With low level dry area and
scattered coverage do not expect much rainfall accumulation much
above a tenth of an inch.

Later this evening and tonight the models are advertising an increase
in the isentropic lift around the 600 to 500 mb layers. Moisture
provided by the monsoonal flow will be in place and therefore the
chances for showers and storms will extend into the overnight. As of
now the better chances for precip will still be for locations along
and north of I-70. Tomorrow there may be a few showers still
lingering around sunrise, but overall dry for most locations. Expect
mostly clear skies and hot temperatures again. Dew points are
forecasted to range between the mid 60s in central KS to the lower
70s in eastern KS. This along with highs in the lower 100s will
produce heat indices between 105 and 113. Therefore the excessive
heat warning continues tomorrow.

.LONG TERM...(Saturday Night through Friday)
Issued at 258 PM CDT FRI JUL 22 2016

The upper level ridge centered across the southern plains will
gradually retrograde westward across the southern high plains and
into the southwest US by Tuesday.

Sunday afternoon and evening, a weak front will slowly push
southward across the northern counties of the CWA. Most of the CWA
will be within the warm sector as the eastern periphary of the upper
ridge axis will extned east across southern KS. Highs Sunday
afternoon will reach the mid 90s across the northern counties with
upper 90s to around 100 degrees across the remainder of the CWA.
Surface dewpoints will remain in the lower 70s across the eastern
half of the CWA with upper 60s across the southwest counties. The
southern two thirds of the CWA should see afternoon heat indices
reach 105 to 108 degrees range, therefore I will keep the excessive
heat warning going through 7 PM CDT Sunday along and south of a
Delphos, to Clay Center, to Holton line.

Scattered showers and isolated thunderstorms will develop Sunday
afternoon along the surface boundary across north central and
northeast KS. The mid-level flow will continue to be weak with only
10 to 20 KTS of H5 flow, So I do not expect any severe
thunderstorms. Surface dewpoints will be high enough that pulse
storms should not produce any microburst winds. The scattered
showers and isolated thunderstorms will slowly move southeast
through the evening hours before they begin to dissipate. Most of
east central KS should remain dry.

Monday through Monday night, the weak front will slowly shift
southward across the CWA and stall out along the southern counties
of the CWA Monday afternoon. As the upper level flow becomes
northwesterly across eastern KS, minor upper level disturbances will
dig southeast and may provide enough lift along and north of the
weak surface front for isolated to scattered thunderstorms to
develop Monday afternoon and into the overnight hours. Most
numerical models show that frontolysis will begin to take place
during the afternoon hours of Monday, thus the surface front will be
ill defined by Monday evening. The mid and upper level flow
continues to look weak, therefore thunderstorms should not be severe.

Increase in cloud cover and a chance for showers and thunderstorms
on Monday should keep Highs a bit cooler with upper 80s across the
extreme northeast counties and lower to mid 90s across the remainder
of the CWA. Heat indices may remain around or slightly below 100
degrees during the afternoon hours.

A unsettled pattern for most of next week as flow over the central
US becomes northwest and series of shortwaves are progged to move
across the area.  This, along with a frontal boundary near the area
through the week, will keep showers and thunderstorm chances from
Monday night though Friday. Overall, it looks like overnight
storms may be the most common feature of next week. Temperatures
will be neat climatological values next week with highs in the
upper 80s and low 90s, and lows in the lower 70s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 609 PM CDT FRI JUL 22 2016

It`s difficult to see much evidence of the weak MCV over north
central KS from the water vapor and profiler data. And given the
overall weakening trend, think this feature has washed out so to
speak. For the rest of the evening, the HRRR and RAP are really
the only solutions to develop additional storms this evening over
northern KS. Meanwhile the larger scale models develop the low
level jet over western KS and hint at some elevated showers moving
into northern KS towards daybreak. Not sure I have a lot of
confidence in the models and think that the stuff out by MHK will
fall apart with the loss of heating and will have to watch the
more robust convection over western KS. Because of this will keep
a VFR forecast with only a VCTS for another hour at MHK.

&&

.TOP Watches/Warnings/Advisories...
Excessive Heat Warning until 7 PM CDT Sunday for KSZ021>024-026-
034>040-054>056-058-059.

Excessive Heat Warning until 7 PM CDT Saturday for KSZ008>012-
020.

&&

$$

SHORT TERM...Sanders
LONG TERM...Gargan/Heller
AVIATION...Wolters



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