Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 291127
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
627 AM CDT Mon Sep 29 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT MON SEP 29 2014

Light to calm winds this morning across much of northeast Kansas ave
lead to patchy dense fog in low lying areas once again. Expect the
fog to clear out by mid morning similar to yesterday. Winds will
remain light this morning then become southeast under 10 mph. South
winds near 10 mph in north central Kansas will become southeast this
afternoon as low pressure deepens in the lee of the Rockies. Good
insolation expected today with warm temperatures in the lower to
middle 80s.

Latest water vapor satellite shows upper low centered over Nevada at
07Z with a lobe of vorticity/energy moving across southern
California. The upper trough will progress eastward into New Mexico
and Colorado by early evening, then ejecting north northeast as a
negative tilt trough into the Western High Plains overnight.
Moisture and instability will be focused over the Western High
Plains this evening then shifting into north central Kansas after
09Z as the low level jet veers to the southwest. Model solutions
have maintained timing of precipitation into north central Kansas by
12Z Tuesday for the last several runs. Therefore expecting most
activity to remain west in the moisture and instability axis have
trimmed precipitation chances prior to 09Z then gradually increase
them through 12Z Tuesday. Low temperatures tonight will be warmer in
the lower to mid 60s with the warmer temperatures across north
central Kansas where cloud cover is expected and lower boundary
layer remains mixed.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 AM CDT MON SEP 29 2014

Mid week periods continue to look active, though specifics remain
uncertain.

As stacked low pressure continues north into the Dakotas, weak
Pacific boundary make slow eastward progress into central Kansas.
Should see elevated mainly modest convection push east into western
locations in the morning on edge of ascent as moisture streams north
ahead of the boundary, with enough clearing for destabilization to
occur in the west in the afternoon ahead of the front. Although
convergence along the front looks weak, setup for moderate shear
and CAPE will bring at least some severe concern for any
convection that can form.

Convective trends through the next few periods will be driven in a
large portion by shortwaves moving through the quick cyclonic flow
aloft, with differences in the larger scale waves already apparent
by Tuesday night. The ECMWF brings a deepening wave into the High
Plains Tuesday night, lowering pressures in western Kansas faster
for a stronger low level parcel response for good moisture
convergence over eastern Kansas. It is in turn faster with the
final main wave, forcing the surface low through south central
Kansas by late Wednesday afternoon and the cold front through east
central Kansas before sunrise Thursday. The domestic models along
with the GEM are weaker and slower with these features in various
degrees, though still have a least a minor wave emerging over the
Rockies Tuesday night and a higher low level theta-e surge north
into south central Kansas Wednesday afternoon and cold front`s
passage around midday Thursday. Even if the slower solutions are
closer to reality, should see continuation and reformation of
thunderstorms Tuesday night as the low level jet increases. Though
shear is not strong, could see a few near-severe hail producers
here. Timing of the wave and how continual convection is into
Wednesday will determine severe weather chances for Wednesday
afternoon and night, but potential will exist for greater shear
and instability for these periods to be the most volatile. Have
kept some thunder through much of the area into Thursday at this
point but severe possibilities this day look to be decreasing. As
for PoP specifics, have tapered eastward progression of Tuesday
precip a bit with little eastward progression of moisture/lift
until Tuesday night. Have kept likely PoPs for Tuesday night into
Wednesday night for much of the area with good setup in well-above
normal PW airmass. At this point however, chances for flooding
rains look low given recent dry stretch and lack of focusing
mechanisms for training storms.

Remaining periods continue to look rather quiet in northwest flow.
This should allow for temps to rebound steadily into the weekend.

&&

.AVIATION...(For the 12Z TAFs through 12Z Tuesday Morning)
Issued at 627 AM CDT MON SEP 29 2014

MVFR to LIFR vsbys expected through 1330Z at TOP otherwise VFR
conditions are expected through the period with some cu developing
around 6kft. Calm winds to become southeast around 5 to 7 kts by
17Z and continue through the period. Convection expected to remain
west of MHK so will leave the terminal dry.

&&

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

$$

SHORT TERM...53
LONG TERM...65
AVIATION...53





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