Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 221106
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
606 AM CDT Tue May 22 2018

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 313 AM CDT Tue May 22 2018

Mid/upper-level low pressure is currently centered over the
southwest US causing a weak ridge aloft over the region. Under the
ridge a low-level jet has developed over portions of central KS this
morning. A majority of the models are advertising isentropic lift on
the 305-310 K theta surfaces in response to the LLJ. Moisture in
that area is modest and should support isolated storms given
elevated cape around 1000 J/kg. The CAMs support this scenario and
show development over north central KS at 9-10z with storms moving
northeastward into NE before dissipating near the MS river valley
around 15-17z. The HRRR has been somewhat of an outlier by keeping
the convection mainly over NE while the RAP has remained rather
consistent with the other models. Therefore have kept slight chances
in those areas through late morning. The GFS is also an outlier
since it has QPF into the afternoon along the state line. Cross over
temperatures yesterday were in the upper 50s and forecasted lows
this morning are in the lower 60s so widespread fog is not expected.
Perhaps some shallow ground fog could be possible close to sunrise
in low lying locations. The rest of the day should be tranquil with
generally light southeast winds and highs in the mid to upper 80s.
Subtle vorticity maximums continue to rotate around the midlevel low
pressure, which may support convection in western KS this afternoon.
This is no obvious low-level feature to help focus this convection
so confidence in the exact location is low at this point. A few of
the CAMs are suggesting storms in portions of north central KS in
the early evening. It appears though that the inhibition should
prevent much development in our area, and given a north-northeast
storm motion the convection that forms in western KS should move
into NE. Low temperatures tonight reach the mid 60s with light wind
speeds through sunrise.

.LONG TERM...(Wednesday through Monday)
Issued at 313 AM CDT Tue May 22 2018

On Wednesday the upper trough over the west will move northeast into
Montana while the upper ridge remains over the central states. The
upper low will merge with another upper level low over southern
Manitoba and move east along the border on Friday flattening the
ridge over the central Plains. However this is short lived as
another upper trough moves into the west for the holiday weekend
while a ridge builds once again across the Plains. Synoptic scale
forcing will be rather weak through the period as best forcing will
be across the northern Plains. Forecast soundings show a weakly
capped environment in the afternoon hours along with weak shear and
moderate instability owing to isolated to scattered convection
chances continuing on and off into the first part of the weekend.
Expecting dry weather for Memorial Day as upper ridge further
establishes itself over the Plains. Temperatures will continue to be
above normal by an average of 10 to 13 degrees through the period.
The warmest temperatures of the week are expected during the Holiday
Weekend. So expecting highs in the upper 80s to lower 90s with lows
in the 60s Wednesday through Memorial Day.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 604 AM CDT Tue May 22 2018

VFR conditions expected through the taf period.

&&

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

$$

SHORT TERM...Sanders
LONG TERM...53
AVIATION...Sanders



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