Area Forecast Discussion
Issued by NWS Wichita, KS

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953
FXUS63 KICT 131739
AFDICT

Area Forecast Discussion
National Weather Service Wichita KS
1139 AM CST Fri Jan 13 2017

.UPDATE...
Issued at 1006 AM CST Fri Jan 13 2017

Updated to delay the onset of freezing precip for areas generally
along and nw of the KS Turnpike.

Feel confident enough after looking at latest trends and 12z model
guidance to delay the onset of freezing rain for most of south
central and central KS several hours. Feel that we shouldn`t see
much in Wichita until after midnight and likely closer to Sat
morning. Meanwhile, se KS will continue to see patches of light
freezing rain throughout the day.

Just a heads up, not sure what is going on with GFS surface temps
but they look unreliable with near 40 creeping into Harper Co by
21z today? So right now leaning toward the NAM/RAP for surface
temps.

&&

.SHORT TERM...(Today through Monday night)
Issued at 353 AM CST Fri Jan 13 2017

Very challenging forecast, with a looming prolonged ice storm
filling the forecast time tonight. Will continue the ice storm
warning as is, although may postpone the start time until midday
Saturday for a few central Kansas counties.

Despite continued model uncertainty regarding surface
temperatures, consensus suggests widespread ice accumulations of
1/4 to 1/2 inch is likely across the region through Sunday night,
with locally higher amounts exceeding 1/2 inch over mainly central
Kansas due to potential for a longer period of sub-freezing
temperatures. Areas of downed tree limbs and powerlines are
likely, with associated power outages. The silver linings are 1)
winds remaining light (hopefully limiting downed limbs and
powerlines), and 2) temperatures warming above freezing most
areas Sunday, melting ice accumulation.

Did not stray too far from going forecast. Primary forecast
challenge is nailing down surface temperatures, as they will be
*K-E-Y* to an accurate freezing rain forecast. As it currently
stands, surface temperatures appear like they could be marginal for
mainly southern portions of the forecast area (i.e. temperatures
hovering around freezing) during the heaviest precipitation Saturday
PM through early Sunday. A nudge of just 1-2 degrees in either
direction could mean mostly rain with little ice accumulations, to
mostly freezing rain with potentially significant ice accumulations.

That said, first round of light freezing rain possibly mixed with
sleet (per NAM/GFS bufr soundings) is expected to affect far
southeast Kansas mainly this morning, with light ice/sleet
accumulations likely. Should be a relative lull tonight into
Saturday morning in between areas of large scale lift, with patchy
areas of light freezing rain/freezing drizzle over southeast
Kansas supporting additional light ice accumulations.

The main batch of large scale ascent and associated precipitation
is expected to arrive Saturday afternoon/evening and persist
through Sunday night, as a negatively tilted trough approaches
from the southwest, inducing strong isentropic ascent/moisture
transport across the region. Given the degree of lift and moisture
and even marginal instability, widespread pockets of moderate to
heavy precipitation are likely, along with embedded claps of
thunder. Where this precipitation falls into sub-freezing surface
temperatures, major ice accumulations are possible, mainly
along/north of Highways 54/400. In contrast, given the absence of
persistent near-surface cold advection, temperatures are expected
to slowly warm Saturday afternoon and night, possibly limiting ice
accumulations across southern portions of the forecast area.

Thankfully, confidence is high that temperatures will gradually
warm above freezing from the south Sunday and Sunday night,
changing everything over to rain and melting all ice accumulation,
with the possible exception of central KS counties north of I-70
where temperatures may remain closer to freezing.

.LONG TERM...(Tuesday through Thursday)
Issued at 353 AM CST Fri Jan 13 2017

Overall synoptic pattern will support above normal temperatures
mid to late next week, with a chance of precipitation moving in by
late week and the weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1126 AM CST Fri Jan 13 2017

Main aviation issue will be increasing freezing rain chances
through the next 24 hours.

Deep upper low remains off of the southern CA coast with low-mid
level warm advection starting across the southern Plains. This has
resulted in increasing precip across the Ozarks into far southeast
KS and into central OK. These are the areas that have been
affected by freezing rain so far. Confidence remains high that any
precip across eastern and central KS through the next 24 hours
will fall as liquid, freezing on any sub freezing surfaces. KCNU
should start to see some patches of -FZRA this afternoon with
chances increasing tonight into Sat morning. KICT will not see any
-FZRA until later tonight, likely after 06z with KHUT not getting
in on the action until later Sat morning.

Surface temps will obviously play a major role on how much ice
accumulates. Right how we have a lean to the temps from the NAM
and RAP, discounting the much warmer GFS. So as the bulk of the
rain falls we should see temps in the 30-33 degree range.

As far as ceilings go, widespread MVFR will be likely at KICT-KCNU
with these conditions slowly spreading north tonight into Sat
morning. The only site that should see IFR ceilings through this
TAF period are KCNU and possibly KICT toward the end of this
taf period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT    29  25  33  30 /  10  40  70  80
Hutchinson      29  23  31  27 /  10  30  60  80
Newton          28  23  32  27 /  10  40  60  80
ElDorado        28  24  33  29 /  20  40  60  80
Winfield-KWLD   30  26  34  31 /  50  60  70  80
Russell         27  20  32  25 /  10  10  40  60
Great Bend      27  21  31  26 /  10  20  50  70
Salina          29  21  31  26 /  10  20  40  70
McPherson       29  22  31  27 /  10  30  50  80
Coffeyville     32  29  35  33 /  70  70  70  80
Chanute         28  27  34  31 /  70  60  70  80
Iola            27  26  33  30 /  60  60  70  80
Parsons-KPPF    30  29  34  33 /  70  70  70  80

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
Ice Storm Warning until 3 AM CST Sunday for KSZ096-098>100.

Ice Storm Warning from 6 PM this evening to noon CST Sunday for
KSZ051>053-067>069-082-083-091-092.

Ice Storm Warning from 6 AM Saturday to 6 AM CST Monday for
KSZ032-033-047-048.

Ice Storm Warning from 6 PM this evening to 6 AM CST Monday for
KSZ049-050.

Ice Storm Warning until noon CST Sunday for KSZ070>072-093>095.

&&

$$

UPDATE...RBL
SHORT TERM...ADK
LONG TERM...ADK
AVIATION...RBL



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