Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Topeka Kansas
632 am CDT Thu Oct 23 2014

..update to aviation forecast discussion...

Short term...(today and tonight)
issued at 329 am CDT Thursday Oct 23 2014

Shortwave trough currently moving across the central and northern
plains this morning. Mid level forcing and some weak frontogenesis
has caused a band of showers to form and progress eastward through
the forecast area. Instability is limited due to mid level capping
and weak lapse rates, so only expect isolated thunder at times.
Rainfall amounts appear to generally be at or under a quarter of an
inch. The back edge of the precipitation has already passed through
north central Kansas and expect that clearing out from west to east to
continue through the morning. Models agree that the last of the rain
should exit east central Kansas around 16z. The uncertainty with this
forecast is how long the clouds linger behind the band of showers.
Also, patchy fog will be possible across north central Kansas later this
morning. Although current infrared shows low stratus already building into
that area, which may limit fog development. If the clouds hold into
the early afternoon hours or later the temperatures today will be
cooler. Some of the short term models are suggesting that the clouds
could hold through the overnight hours across most of the area. Have
lowered the high temps a few degrees into the mid to low 70s to
account for this scenario. Also kept the trend of the coolest
locations being east and north central Kansas where the clouds will
likely linger the longest. The NAM is suggesting clouds will last
through tonight only to clear out early tomorrow morning, which
could set up the potential for fog again. Confidence in the forecast
beyond mid day is low at this point.

Long term...(friday through wednesday)
issued at 329 am CDT Thursday Oct 23 2014

Friday through Saturday...a southern stream upper level ridge will
move eastward into the southern and Central Plains.

On Friday, westerly 850mb winds will advect 19-22 degree c 850mb temps
across the County Warning Area Friday afternoon. Deeper mixing will allow surface
winds to become southwesterly and temperatures to warm into the
lower to mid 80s.

An upper level trough will ride over the Southern Plains ridge axis
and deepen as it digs southeast across the Great Lakes states. Weak
cold air advection across the upper Midwest into the mid MS River Valley Friday
night into Saturday morning will cause a weak back door cold front
to push southwest across the County Warning Area on Saturday. Highs will be slightly
cooler in the mid 70s to around 80 degrees.

Sunday through Monday, an upper level trough across the western US
will move east across the central rockies into the High Plains by
00z Tuesday. A Lee surface trough will deepen across western Kansas during
the day on Sunday. Stronger southerly winds will help to warm
temperatures into the lower to mid 80s Sunday afternoon. A surface cold
front will begin to push southeast into north central Kansas Monday
afternoon and there may be enough surface convergence ahead of
the front for isolated showers and thunderstorms to develop late
Monday afternoon. Southerly winds will allow temperatures to warm
into the mid to upper 70s despite increasing cloud cover.

Monday night through Tuesday evening, the upper level trough will
move east across the plains and amplify. Stronger ascent will allow
showers and thunderstorms to develop across eastern Kansas ahead of the
front as well as Post frontal. The front will move southeast of the
County Warning Area by 12z Tuesday thus most of the thunderstorms should move east into
MO. The Post frontal rain showers will last through most of the day
but should move out of east central Kansas during the early evening
hours of Tuesday as the upper level trough axis moves east into MO.
Highs on Tuesday will only reach the mid 60s with cloud cover, periods
of light rain and northwest winds of 15 to 20 miles per hour.

Wednesday, skies should clear during the morning hours. A surface
ridge of high pressure will move southeast across the County Warning Area into OK
and Arkansas by the late afternoon hours. Highs will continue to be in the
lower to mid 60s despite insolation during much of the day.


Aviation...(for the 12z tafs through 12z Friday morning)
issued at 621 am CDT Thursday Oct 23 2014

Stratus will be the main issue with this taf period. For now the
cigs appear to stay in the MVFR category and the vis should remain
in VFR. Most of the models are suggesting the clouds will linger
through 00z Fri. At some point the cigs could lift to VFR,
although given the model spread pinning down that time is difficult.


Top watches/warnings/advisories...


Short term...Sanders
long term...gargan

National Weather Service Glossary of Abbreviations