Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 251140
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
640 AM CDT Wed Mar 25 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 403 AM CDT WED MAR 25 2015

Early this morning a stratus deck remained firmly in place across
northeastern Kansas. This cloud cover combined with the moist ground
from yesterday`s rain resulted in some areas of dense fog developing
across portions of north central and northeast Kansas. Short-range
model guidance suggests that these areas of dense fog may linger
through mid morning before clearing out initially near the
Kansas/Nebraska border.

The region will remain mostly cloudy today as a mid-level trough
approaches the area, helping to push a cold front southeastward
across the CWA late morning into mid afternoon. In addition to this
passage of the cold front, models show the warm front extending from
the surface low over the Texas/Oklahoma panhandles lifting just
north of the Kansas/Oklahoma border by this afternoon. This warm
front will be the focus for some decent lift and modest instability
along and south of the boundary. With a southwesterly low-level jet
in place across southeast Kansas this afternoon, expect overrunning
of moisture northward into east central Kansas, resulting in
increasing chances for precipitation by early this afternoon. While
the better instability looks to remain focused closer to the
Kansas/Oklahoma border, some weak elevated instability should be
present over east central Kansas to produce some isolated
thunderstorms this afternoon. While the better chances for
precipitation will be focused across east central Kansas, some
increased lift will be present behind the cold front as a vort max
from the approaching mid-level trough skims across far northern
Kansas. While the better forcing looks to remain over southern
Nebraska and northwestern Kansas during the day, still could see a
few stray showers developing across far north central Kansas today.
However, initially the main challenge will be overcoming the
mid-level dry air that is distinctly noted above the early morning
stratus deck in the model soundings. As a result, conditions may be
predominantly dry across far northern Kansas this morning before the
low/mid levels are able to better saturate by mid to late afternoon.
With this in mind, have trimmed back PoPs for this morning across
this area. Better forcing will be in place across the forecast area
by late afternoon through this evening as the vort max moves over
the area, resulting in more widespread chances for showers and
isolated thunderstorms mid afternoon through this evening.
Precipitation should end from west to east as the mid-level trough
advances over the region, with dry conditions by the overnight
hours.

As for temperatures, have a non-diurnal temperature trend going for
today as temperatures should drop this afternoon across north
central Kansas behind the passage of the cold front. With extensive
cloud cover expected across the region today, have dropped
temperatures by a few degrees with highs ranging from the low/mid
50s north to the mid 60s south. With diminishing cloud cover
overnight, low temperatures should be able to drop into the upper
20s to mid 30s.

.LONG TERM...(Thursday through Tuesday)
Issued at 403 AM CDT WED MAR 25 2015

Models are showing a wave moving quickly southward on the back side
of the upper trough on Thursday and Thursday Evening. Speed of the
wave and associated forcing still in question Thursday night and
there is a consensus that there will be the potential for light rain
in the afternoon and evening and most likely a quick exit Thursday
night. Thermal profiles suggest all rain with a mix of rain and snow
late toward the end of the event. Temperatures cool into the upper
20s to lower 30s. Another fast moving wave will bring another chance
of light precipitation on Friday night to the area. Amounts look to
be on the light side with limited moisture and soundings show rain
with a rain and snow mix later in the night. Differences in the
models with the timing and placement of the PV anomaly and
frontogenetic forcing and will maintain a low confidence
precipitation forecast. Highs in the 50s on Friday with south winds.
Lows fall into the lower to middle 30s Saturday morning.

Rising heights on Saturday and warm advection will temperatures to
warm back into the 60s in north central Kansas with the 50s across
the northeast. Lower boundary layer remains mixed Saturday night
with southerly winds and have bumped lows up a couple of degrees
into the lower to mid 40s. A upper trough moving across the northern
Plains on Sunday will sweep a cool front southeast across northeast
Kansas through the day. Temperatures warm back into the 70s for much
of the area with upper 60s in the far northeast. GFS and ECMWF
differ with the strength of the upper trough with the GFS deeper and
further south. Have favored the GFS and GEM which offer similar
solutions with respect to the strength of the wave and forcing
remaining to the north for any precipitation. Southerly return flow
develops Monday and continues on Tuesday as a shortwave trough
develops in the SW states and Mexico. Models differ with the
evolution of the upper trough through Tuesday. Will keep low pops
for the southeast CWA for now given uncertainty and confidence in
any on solution. Highs in the 60s Monday and lower 70s Tuesday. Lows
Monday night in the low to mid 40s.

&&

.AVIATION...(For the 12Z TAFs through 12Z Thursday Morning)
Issued at 639 AM CDT WED MAR 25 2015

For the 12z TAFs, LIFR to VLIFR cigs/vis this morning with areas of
dense fog near the TAF sites. These cigs/vis should briefly improve
by mid to late morning to VFR conditions before areas of rain
develop near the TAF sites late this afternoon through this evening.
Conditions should quickly improve by late this evening with cloud
cover scattering out into Friday morning.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until 11 AM CDT this morning FOR KSZ008>012-
020>024-026-036-038-039.

&&

$$

SHORT TERM...Hennecke
LONG TERM...53
AVIATION...Hennecke






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