Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 232343
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
543 PM CST Thu Feb 23 2017

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Friday)
Issued at 245 PM CST Thu Feb 23 2017

The short-term period will consist of precipitation chances along
with a return more seasonable February temperatures. As of Thursday
afternoon a deepening surface low was situated over southwestern KS.
An east to west oriented warm was located over the southern CWA. Mid
level lapse rates continue to steepened in response to the upper
level low progressing from northern Colorado into western Nebraska.
The biggest question mark through the evening hours is whether the
EML will hold across northern KS. Latest 00Z-03Z forecast soundings
from the RAP and HRRR suggest a stronger EML than previous runs.
Sufficient large scale forcing is expected as a upper level short
wave will move across north-central KS and south-central KS. Modest
isentropic lift within the 300-305K will remain across the area
through 06Z. If parcels were able to break the cap, around 500 J/KG
of MUcape and 40-50 knots of effective shear would be available.
With this potential for supercells, SPC has upgraded portions of
north-central KS to a slight risk with the primary hazard being
large hail.

We then transition back to typical winter conditions overnight into
Friday. As the surface low pushes east of the area overnight, CAA in
response to gusty northwest winds will cool temperatures
throughout the day on Friday. High temperatures for Friday will
occur at midnight, with afternoon temperatures ranging from the
low 30s in the north to low 40s in the southern areas. The bulk of
precipitation associated with upper level low in Nebraska is
expected to stay north of the area. However, sufficient low level
moisture may exist for light wintry precipitation, mainly along
the KS/NE border, possibly as far south as I-70 throughout the day
on Friday. Forecast soundings suggest a brief period near dawn
across far north-central KS, where only low level saturation
exists. With surface temperatures hovering near freezing, I have
introduced a couple hours of light freezing drizzle. Pavement
temperatures are well above freezing across the entire area,
therefore expect minimal accumulation and impacts to roads.

.LONG TERM...(Friday night through Thursday)
Issued at 245 PM CST Thu Feb 23 2017

Lingering deformation zone on the backside of our departing system
may continue to bring light snow to portions of far NE Kansas early
Friday night, but little to no accrual is expected. Surface ridging
will build in overnight Friday into Saturday morning resulting in a
gradual decrease in winds and cloud cover. The progressive zonal
flow pattern behind the departing trough will allow the 1026 mb high
to slide through the region through the afternoon on Saturday and
set the stage for our next system on Sunday. Medium range solutions
are struggling with how this upstream wave will interact with a
cutoff low NE of Hawaii, which is having a direct impact on the
timing and location of the wave as it translates ESE on Sunday. The
GFS solution brings out a more amplified H500 wave for Sunday, which
in turn brings more precip to the area. Continued using a blend of
the GFS/ECMWF for POPs through this period, with confidence in this
portion of the forecast lower than average. Temperatures for the
weekend will linger around climatological average for this time of
year with a slight warming trend for Sunday as weak WAA takes place
behind the departing ridge.

An active pattern will continue into mid week as a longwave trough
slides east across the CONUS. This will likely bring another round
of precip (mostly in the form of rain) to the area on Tuesday into
Wednesday, but as with the Sunday system, confidence in the
placement of the precip is lower than average. Highs on Tuesday will
likely rebound back into the 60s ahead of the approaching frontal
boundary, falling back into the 40s and 50s for mid to late week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 527 PM CST Thu Feb 23 2017

A surface cold front will push southeast across the terminals this
evening and switch winds to north at 14 KTS with gusts to 22 KTS.
There may be a chance for showers at MHK this evening...and
possibly some isolated showers at KFOE and KTOP late this evening.
Low stratus of 1000 to 1500 feet will move southeast across the
TAF sites during the early morning hours of Friday. The ceilings
may gradually rise above 2,000 feet during the late afternoon
hours of Friday. There may also be some isolated to scattered
showers Friday afternoon.

&&

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

$$

SHORT TERM...Baerg
LONG TERM...Skow
AVIATION...Gargan



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