Area Forecast Discussion
Issued by NWS Topeka, KS
FXUS63 KTOP 260533
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1133 PM CST Thu Dec 25 2014
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Friday)
Issued at 236 PM CST THU DEC 25 2014
This afternoon the winds begin to diminish with the loss of
daytime heating. This should occur some time right around sunset
therefore kept the wind advisory as it stands. During the evening
hours there may be occasional gusts as the boundary layer tries to
decouple over southeast portions of the forecast area. This is
where the pressure gradient remains the strongest relatively
speaking. Further west in central KS a front approaches from the
northwest leading to a lesser gradient there. The front slides
through the area overnight tonight causing a brief period of light
winds. Low temperatures tonight dip into the upper 20s in north
central KS behind the front, and only drop into the upper 30s in
east central KS.
The front should be exiting the forecast area shortly after
sunrise tomorrow. During the day tomorrow a lead shortwave will
eject from the Central Rockies, which will bring precip into north
central KS in the late afternoon hours. Ahead of the system gulf
moisture surges north into eastern KS where it will advect over
the front to our south. Type of precipitation is tricky, with
surface temperatures very near the freezing mark. Precipitation
should start out as rain or drizzle early afternoon, but may cross
over to a light freezing drizzle in the north central counties for
a few hours in the late afternoon as the front deepens, and before
saturation in the snow growth layer occurs. Across eastern KS the
soundings indicate that most of the lift will be located in the
low levels leading to more of a light rain or drizzle with temps
above freezing. Do not expect much measurable precip before 00Z
Sat. In fact the NAM indicates that most locations could receive
mainly drizzle during the afternoon hours.
.LONG TERM...(Friday Night through Thursday)
Issued at 236 PM CST THU DEC 25 2014
Friday evening into Saturday...Think precipitation will switch
over to a light snow by the evening hours. Piece of stronger
energy clips these NW counties in the overnight hours, and may
bring an inch of snow to that area, with decreasing amount to the
south and east. Expect only a trace to possibly a dusting south of
the interstate. Precipitation moves eastward quickly as the wave
opens and lifts to the northeast, leaving highs in the upper 20s
to low 30s, with lows falling into the teens Saturday night.
Sunday bring a day with high temperatures near normal before the
next strong cold front sweeps into the area on Monday. Monday may
also see some high temperatures reach back up into the middle 30s
before the front drives through in the afternoon hours. GFS
solution is faster, and would cool down quicker. Overnight Monday
into Tuesday brings a chance for another brief round of snow as
the strong high continues to slide down the front range. Chances
are slightly better in the western counties where better moisture
and lift are present. Highs drop to single digits to teens, with
highs on Tuesday in the teens most areas save the far southeast.
Very cold lows in the single digits settle in for Tuesday night as
1041mb high centers over western Kansas.
Larger scale pattern drops energy southwestward over southern
California with a broad large scale upper trof over the eastern
North American coast. This leaves the area under generally
westerly flow and surface temperatures try to moderate back into
the 20s on Wednesday and 30s for Thursday.
.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1133 PM CST THU DEC 25 2014
VFR conditions expected to continue until shortly after frontal
passage during the 14Z-17Z time period. Cold front should move
through MHK by 14Z-15Z and 16Z-17Z at TOP and FOE. MVFR cigs are
expected behind the front, along with some IFR cigs developing
after 23Z. Some light precipitation mainly liquid at TOP and FOE
possible, as well as a RASN at MHK transitioning to -SN after 00Z.
Confidence not high enough to go with prevailing precip so left
out for now until confidence increases.