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 132347
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
647 PM CDT Sun Jul 13 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Monday)
Issued at 345 PM CDT SUN JUL 13 2014

The cold front that supported the showers and isolated thunderstorms
this morning has progressed just south of the forecast area, but
regional radar is showing some scattered precipitation developing
behind this boundary in west central Missouri and into far east
central Kansas. Could see this isolated activity over the far
southeastern part of the forecast area continue through the
afternoon hours before diminishing as the cold front tracks further
to the south. Do not anticipate any severe weather with this
activity as the forcing looks to be fairly weak and 0-6km bulk shear
values should only be around 30kts. Cloud cover hung around across
much of central and east central Kansas behind the cold front
through much of the afternoon, resulting in cooler high temperatures
compared to yesterday, with readings topping out in the mid/upper
80s. Surface high pressure over eastern Colorado will extend
eastward across Kansas this evening and overnight, resulting in
light and variable winds, mostly clear skies, and decent radiational
cooling with lows dropping into the mid/upper 60s.

Water vapor imagery showed the strong closed mid-level low spinning
north-northwest of the Great Lakes region with an embedded shortwave
developing along the western edge of the low over south-central
Canada. Models show this wave strengthening as it dives southward
into the north central U.S. overnight through Monday with the
mid-level trough deepening southwestward into the Central Plains.
This deepening trough will help to push a narrow wedge of surface
low pressure and the associated cold front (which was stretched
across northeast Nebraska through central Iowa as of 20z) southward
toward the area overnight. There are still some slight model
discrepancies with regards to how quickly this boundary enters the
forecast area, but in general it looks to move into far
northern/northeast Kansas between 09z-12z Monday. A line of showers
and thunderstorms will develop along and behind the front,
progressing southward over the area through the morning and into the
afternoon. The front should be south of the forecast area by late
morning/early afternoon, but there is also some uncertainty with how
quickly precipitation diminishes and exits the area. As surface high
pressure over the Northern Plains advances southward into the area
behind the front, it will be bringing much drier air into the
mid-levels. As a result, conditions may dry out across portions of
far northern Kansas by late morning and potentially result in the
precipitation becoming more scattered over east central Kansas by
the afternoon before finally drying out across the entire forecast
area by Monday evening. MUCAPE values look to be upwards of
2500-3500J/kg with 30-40kts of 0-6km bulk shear, but model soundings
show these storms being very high-based with somewhat weak mid-level
lift, so the potential for severe storms looks to be low at this time.
With this frontal passage during the day, have a non-diurnal trend
with temperatures for Monday with highs continuing to trend cooler,
ranging from near 80 degrees around the KS/NE border to the middle 80s
over east central Kansas.

.LONG TERM...(Monday Night through Sunday)
Issued at 345 PM CDT SUN JUL 13 2014

Much cooler and drier air still forecast to work southward across the
cwa through the night with 850 temps by sunrise Tuesday falling into
the 8 to 10 deg C range northeast to southwest respectively across
the cwa. The combination of clear skies and light winds still on
track by sunrise Tuesday to likely make it the coolest morning of
the week with lows from the low 50s north to middle 50s south
which again will be near or just above record lows for July 15th.

By Tuesday night into Wednesday...models bring the strong shortwave
trough...now off the OR coastline...over the ridge axis and
southeastward into the central and northern High Plains. This in
combination with good upslope flow and increasing moisture advection
will develop a large area of showers and thunderstorms to the west
of the county warning area...which may clip the far west and
southern portions of the cwa with showers/thunderstorms. Models
showing a slight westward shift to precipitation from yesterday and
last night with dry air holding stronger over eastern KS...so have
kept pops low for the western/southern areas late Tuesday night and
thru the day Wednesday. The upper level wave will progress
southeastward into the southern plains Thursday so will end rain
chances across the south by that time. Low temps Wednesday morning
in the middle/upper 50s will be slightly milder with more clouds
most areas than Tuesday morning. Will keep lows in the mid/upper 50s
into Thursday morning.

As the upper low passes on to the south and east...will keep the cwa
precipitation free into Saturday before another wave moves through
the area on the eastern side of amplifying upper ridge with another
chance for thunderstorms Saturday night and Sunday. At the same
time...will gradually warm temps through the period with highs
warming from the middle 70s Wednesday to the 80s on Friday...then
the upper 80s to lower 90s by Sunday. Lows will rise from the upper
50s and lower 60s Friday to around 70 by Sunday...which is very
close to average for mid July.

&&

.AVIATION...(For the 00Z TAFs through 00Z Monday Evening)
Issued at 639 PM CDT SUN JUL 13 2014

VFR prevails as surface high pressure brings light northerly winds
becoming variable overnight. FROPA along with sct TSRA is expected
to impact terminals aft 13Z. Winds veer to the northwest from
05-10 kts, with occasional gusts possible during the afternoon.
Short term guidance is highlighting the highest probability of light
TSRA from 14Z at KMHK to 19Z at KTOP/KFOE. Inserted a TEMPO where
cigs may lower to near 3 kft, possibly MVFR if precip intensity is
higher.

&&

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

$$

SHORT TERM...Hennecke
LONG TERM...63
AVIATION...Bowen






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