Area Forecast Discussion
Issued by NWS Topeka, KS
FXUS63 KTOP 191120
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
620 AM CDT Fri Sep 19 2014
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 232 AM CDT FRI SEP 19 2014
Upper level ridge is gradually building over the plains, which has
allowed the isentropic lift to become more focused over southeast NE
later this morning. Therefore the area remains dry through tonight.
The lee side trough has deepened through the course of the day as
several shortwaves track over the northern plains. This has
increased the surface pressure gradient in central KS limiting the
fog development there. In far eastern KS the winds are lighter and
skies were clear for most of the evening keeping the low level
inversion in place as well as the moisture. Also, a high pressure
that extended into the mid MS valley is currently retreating
allowing the return flow to become better established. Dew points
will be on the rise through out the day ahead of next system to
arrive tomorrow. Latest satellite is showing low stratus developing
over eastern KS and western MO. Most of the guidance agrees with
this trend and keeps the stratus socked in until the afternoon. As
the dew points increase and inversion holds strong fog is also a
possibility, which may be dense in some locations. Expect that the
fog will lift sometime during the late morning hours, and seems less
likely across the western half on the forecast area. Western areas
will see mostly clear skies today and with an increase in mid level
temps highs reach the upper 80s. Further east where the clouds hold
on longer into the day temperatures will be slow to warm and
slightly cooler. Expect that once the clouds scatter out high
temperatures reach the low to mid 80s. Southerly winds will be on
the increase today with gusts up to 25 mph across north central KS.
Clouds will also increase from west to east later tonight as the
front approaches the region.
.LONG TERM...(Saturday through Thursday)
Issued at 232 AM CDT FRI SEP 19 2014
Models generally agree in bringing the next front through the
forecast area on Saturday afternoon and moving into southern
Kansas Saturday evening. Considering dewpoints are forecast in the
upper 60s near 70 and high temperatures around 85, will make for a
muggy day before the front passes, with it feeling more like near
90. Also with later day timing comes better heating and
instability, with CAPE near 2000j/kg over the area as the front
moves in. Well mixed boundary layer makes for a wind threat with
stronger storms, and steeper lapse rates aloft make for a hail
threat as well. Shear remains generally around 25-30kts and would
be enough to produce a few strong storms as the front passes. As
high pressure still moving in overnight, lows in the lower 60s
expected most areas. Sunday brings cooler dry conditions with 70s
far northeast to lower 80s in the southwest counties. Could see
fog chances return Sunday night as winds lighten and skies clear.
Dry forecast continues for much of the day Monday with highs in
Next upper trof is on approach for Monday night and into the
middle, and latest model runs showing a little more consistency in
timing. Tuesday brings the upper trof over the northern and Central
Plains, lifting it slowly toward the Great Lakes through
Wednesday. Precipitation chances continue through this time, with
late Tuesday early Wednesday bringing better chances at this time.
Upper ridge over the Ohio valley influenced by a tropical wave
moving into the southeastern states, and how this impacts the
ridge will result in timing influences for the trof over our area.
Temperatures remain in the 70s with overnight lows in the 50s.
.AVIATION...(For the 12Z TAFs through 12Z Saturday Morning)
Issued at 614 AM CDT FRI SEP 19 2014
There is good agreement that the IFR stratus will move east and
scatter out later this morning. MHK is on the western edge of the
stratus deck and may stay VFR, but did include a tempo in case
the clouds build into the site. At TOP/FOE there may be brief
periods of LIFR ceilings, although the visibilities may not be
impacted that much. Winds will pick up out of the south and
gradually shift to the southwest late in the period. There could
be occasional gusts up to 20 kt especially at MHK.