Area Forecast Discussion
Issued by NWS Topeka, KS
FXUS63 KTOP 242319
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
519 PM CST TUE NOV 24 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 342 AM CST TUE NOV 24 2015
Dry and above average temperatures are expected once again today.
Main focus centers on the poignant upper trough beginning to come
onshore across the Pac Northwest. This will affect the area
beginning on Wednesday evening. Ahead of this system, a lead
shortwave trough was observed over Utah, pushing east into the
central plains tonight. This will reinforce the surface trough
across western Kansas, increasing southerly winds between 15 and 20
mph sustained in the afternoon. Previous trends and warmer air from
850 mb mixing to the sfc lead to raising highs a few degrees warmer
in the low to middle 60s. As the lead trough progresses over the CWA
this evening, low level moisture below 850 mb quickly spreads into
the region. Isentropic lift on the 285K to 290K surfaces picks up
after 06Z adding a mention of areas of drizzle as low level stratus
builds in early Wednesday morning. Cloud insulation and stout
southerly winds through the evening will keep overnight lows in the
mid to upper 40s.
.LONG TERM...(Wednesday through Monday)
Issued at 342 AM CST TUE NOV 24 2015
Warm advection and isentropic lift will continue across eastern
Kansas on Wednesday ahead of an approaching frontal boundary and
energy ejecting out of the southwest upper trough. Forecast
soundings suggest mainly drizzle with increasing rain chances in the
afternoon. Upper trough moving across the Northern Plains will bring
a cold front southeast into north central Kansas Wednesday evening
and then gradually across the rest of the cwa during the afternoon
hours on Thanksgiving Day. Models are still differing on the speed
of the cold air behind the front, but overall consensus is for highs
in the morning and around mid day then falling through the afternoon
hours. Models soundings and planview show persistent warm nose aloft
over the shallow cold air at the surface. This will set the stage
for a wintry mix of precipitation in the afternoon hours in north
central Kansas where a mix of rain, freezing rain and sleet is
expected while the rest of the forecast area will remain all rain.
The upper low will remain cut off in the western U.S. into Friday
before moving out into the Plains later in the weekend into early
next week. With southwest flow aloft and ejecting energy through the
weekend into next week expect chances for precipitation to continue
into Monday. Main concern will be Thursday night into Friday morning
where there is a good signal for freezing rain and could see around
an tenth of an inch of ice accumulation across much of the CWA.
Temperatures should warm above freezing Friday afternoon for any
precipitation to change over to rain. Model differences continue
with the speed and movement of the cut off low in the west, given
the differences in speed and thermal profiles will keep a mix of
rain and snow over the weekend.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 519 PM CST TUE NOV 24 2015
MVFR ceilings are expected to develop later this evening at all
terminals. Light drizzle is also expected to develop near dawn
Wednesday morning. IFR ceilings will be possible throughout the
day on Wednesday, especially with heavier pockets of drizzle.
However, will defer IFR conditions to later outlooks due to low
confidence in intensity of drizzle.
Winter Storm Watch from Thursday afternoon through late Thursday
night for KSZ008>012-020>024-026-034>039.