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000
FXUS63 KTOP 111152 AAA
AFDTOP

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TOPEKA KS
652 AM CDT Tue Mar 11 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 344 AM CDT TUE MAR 11 2014

Focus of today`s forecast centers on the strong and gusty winds as a
cold front approaches from the northwest. There is also the
potential for fire weather concerns especially during the afternoon
period. Beginning early this evening, very strong northerly winds
persist as precipitation chances increase.

Cloud cover in the vicinity of the surface cold front was noted at 09Z
across central Nebraska. Strong pressure falls associated with the
surface low over western Kansas were allowing southerly winds to
gradually increase between 10 and 15 mph sustained over north
central areas. Expect the strong winds to spread eastward through
the morning with southerly wind gusts up to 30 mph as the low pressure
deepens eastward. Dewpoint temperatures in the lower 40s currently
observed over Oklahoma are forecast to advect northward into
portions of east central areas by this afternoon. However, forecast
soundings depict the strong winds mixing much drier air into the
boundary layer. Based on how models have previously handled this
scenario, sided closer to the drier side on dewpoint temperatures
mostly in the 30s, perhaps 40 over far east central KS. In terms of
temperatures, short term guidance is in good agreement on the cold
front passing through Concordia in the early afternoon, reaching the
Topeka and Emporia areas just after peak heating in the late afternoon.
Compressional warming along the boundary and newer guidance coming
in much warmer will setup a decent high temp gradient across the
area. Highs range from the upper 50s over north central KS, to the
low 70s for far northeast Kansas, to the mid/upper 70s over east
central KS. These conditions will create the potential for wildfire
danger across the area. Please the fire weather discussion below for
more details.

The upper trough quickly enters Kansas by late afternoon as the
pressure gradient tightens behind the frontal boundary. The strong
southerly winds in the afternoon followed by even stronger northerly
winds behind the boundary has warranted the wind advisory to remain
in effect this afternoon and evening. Precipitation develops over
Nebraska, spreading southward in the afternoon. Precip type is all
rain through at least 7 PM. The cooler air aloft shows steepening
mid level lapse rates with some instability developing just to the
east in MO. Could not rule out an isolated thunderstorm embedded
within the rain along/behind the boundary. Areas along and south of
Interstate 35 see the best chance for this occurrence.

As the column saturates and cools close to the freezing mark this
evening, rain begins to mix with snow over north central and
northeast portions of the area. This transition gradually spreads
south and east by 10 PM. The NAM continues to be the outlier with
the strongest frontogenetical forcing and available moisture, over
half of an inch. Sided closer to consensus in QPF amounts being near
or less than a quarter of an inch by the time precip exits early
Wednesday morning. Believe snow will be difficult to accumulate
given temps near the transition mark allowing for the rain to melt
most of the snow. Best chances for snowfall accumulation from 0.5 to
an inch lie near the Kansas and Nebraska border. The system exits by
sunrise Wednesday morning, clearing skies west to east with falling
low temps in the upper 20s.

.LONG TERM...(Wednesday through Monday)
Issued at 344 AM CDT TUE MAR 11 2014

The long term portion of the forecast will be rather quiet,
characterized by upper flow from the west northwest with short wave
troughing expected to impact the area today, Friday, Sunday, and
perhaps by the middle of next week. Temperatures are unlikely to
warm to the levels of early this week with the northwesterly flow in
place, but there will be periods of modification and warmer temps.
Wednesday will be the cool day of the week as cold advection is
rather strong tonight into the day on Wednesday. There is also a
fair likelihood for broken stratus or stratocu through the afternoon
which would limit temps too. Then expect modification back into the
60s for Thursday and Friday, with Friday highs dependent on timing
of a weak cold frontal passage...although it shouldn`t be much
colder post-frontal. Saturday should then hold in the 60s before a
stronger front passes through with the Sunday system...keeping highs
in the 50s (near normal) for Sunday and Monday.

In terms of precipitation, while there are periods of short wave
energy moving through the region, there do not appear to be any
great chances for precip. Today`s cold front will do a very nice job
of scouring moisture all the way into the Gulf, and most indications
suggest the system on Friday will focus most of the ascent south of
the local forecast area. The GFS is rather aggressive with this
system, and seems to be overdoing intensity and moisture content so
have opted toward a dry forecast for now. Expect a bit more focused
ascent by Saturday night, although still not particularly strong,
and seem to have enough moisture to work with to warrant chance POPs
in the area. If precip should develop, temperature profiles suggest
initial rain would change to or mix with snow by early Sunday
morning. Otherwise, all other forecast periods through Monday have a
high likelihood of being dry.

&&

.AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning)
Issued at 651 AM CDT TUE MAR 11 2014

Main concerns for terminals are the increasing southerly winds and a fropa
later this afternoon. Light south winds this morning veer to the
southwest and increase above 10 kts sustained with gusts above 20
kts aft 15Z. Fropa is on track to pass KMHK aft 21Z and KFOE/KTOP
aft 22Z with increase in northerly winds between 20-30 kts
sustained with gusts near 40 kts through 08Z at KMHK and 10Z at
KTOP/KFOE. VFR ceilings this afternoon lower to MVFR behind the fropa.
Light rain is the primary precipitation type at KTOP/KFOE with
best probabilities for rain/snow mix at KMHK aft 00Z. Gusty
northeast winds overnight persist through 12Z Wednesday as MVFR
stratus and precip end by 10Z.

&&

.FIRE WEATHER...
Issued at 651 AM CDT TUE MAR 11 2014

Strong southerly winds increase ahead of an approaching cold front
to the northwest this afternoon. Expect wind speeds between 15 and
25 mph sustained with gusts up to 35 mph before the boundary arrives
across locations along and south of Interstate 70. Winds shift by the
afternoon to the north, increasing between 25 and 35 mph sustained.
Gusts up to 45 mph are likely through the early evening. While the
winds alone will create dangerous fire weather conditions,
uncertainty exists on how low the RH values will fall. Guidance
holds dewpoint temperatures in the 30s to low 40s by late afternoon
as moisture pulls northward ahead of the front. Lowest minimum
humidity values are in the 30 percent range in the above mentioned
areas. However, very dry air aloft may mix down to the surface,
lowering the minimum relative humidity readings closer to red flag
criteria. Will continue to monitor conditions for possible red flag
warning issuance today.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY from 4 PM this afternoon to 1 AM CDT Wednesday FOR
KSZ011-012-022>024-026-036>040-054>056-058-059.

WIND ADVISORY from 1 PM this afternoon to 10 PM CDT this evening
FOR KSZ008>010-020-021-034-035.

&&

$$

SHORT TERM...Bowen
LONG TERM...Barjenbruch
AVIATION...Bowen
FIRE WEATHER...Bowen