000
FXUS63 KTOP 142056
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
356 PM CDT Fri Mar 14 2014

.SHORT TERM...(This Evening through Saturday)
Issued at 348 PM CDT FRI MAR 14 2014

An upper level trough across the southwestern US will slowly move
east into western TX on Saturday. A secondary upper trough digging
southeast out of the Pacific northwest will begin to phase with the
west TX H5 trough as it digs southeast across the central high
plains late Saturday afternoon.

Tonight, winds should become light with mostly clear skies.
overnight lows will only drop off into the mid to upper 30s.

As the H5 trough moves east into west TX, a lee side surface trough
will deepen across the high plains Tonight and Saturday morning
before moving east into central KS by the late afternoon hours. A
surface cold front will will move southeast across western KS
through the day and should be moving into the western counties of
the CWA by 00Z SUN. south-southwesterly surface winds ahead of the
surface trough/front will allow for deeper moisture to move
northeast from central OK across southeast KS. The northwest edge of
the deeper moisture will begin to move northeast along and south of
the interstate 35 during the mid and late afternoon hours. As the
moisture moves northeast, isentropic lift plus any ascent ahead of
the H5 trough will cause scattered showers and perhaps a few
isolated thunderstorms to develop. Forecasted MLCAPE will only be
200-600 j/kg along and south of interstate 35, thus any
thunderstorms that develop will only have lightning as a hazard. the
surface to 600MB effective shear looks weak with only 20 to 30 kts
of effective shear across the southeast portions of the CWA. Highs
on Saturday should warm into the upper 60s to mid 70s.


.LONG TERM...(Saturday Night through Friday)
Issued at 348 PM CDT FRI MAR 14 2014

Saturday night into Sunday, a positively-tilted mid-level trough
will be deepening further south across the Central and Southern
Plains. As this trough continues to slide southward over the region,
it will help to push the cold front that is expected to track into
northern Kansas earlier in the day south of the region by 06z,
however there is still some model uncertainty with the exact timing
of this frontal passage. However, the models do agree upon a very
tight pressure gradient quickly developing over the region behind
this frontal passage Saturday night through Sunday morning before
gradually weakening Sunday afternoon. Could see northerly winds
sustained at 20-25 mph with gusts upwards of 30-35mph through this
period. With this strong northerly flow in place, expect good cold
air advection to occur overnight into Sunday with temperatures
quickly plummeting from the 50s/60s in the early evening to the
upper 20s/low 30s Sunday morning. Could see some light post-frontal
precipitation develop Saturday night through Sunday morning as both
the NAM/GFS show some modest low to mid-level frontogenetical
forcing present, but this better lift should shift east of the area
by late morning/early afternoon. This light precipitation will start
out in the form of rain due to the mild daytime temperatures on
Saturday, and cannot rule out the potential for a few isolated
thunderstorms as models show some weak instability (ranging from
roughly 200-500 J/kg of MUCAPE) building into east central Kansas
Saturday evening. However, 0-6km bulk shear continues to look weak
across that area at less than 25kts. As temperatures drop closer to
the freezing mark overnight into Sunday morning, could see this
precipitation transitioning over to snow. It`s worth noting that the
GFS soundings show the potential for a warm nose near 800mb as the
surface temperatures drop near or below freezing, suggesting the
potential for a brief period of mixed precipitation. Do not have any
mention of this in the forecast at this time, but will need to
continue to monitor this feature in future model runs. With the
potential for light snow Sunday morning, it will be difficult to get
much in the way of accumulation due to the warmer ground temperatures,
however cannot rule out the possibility of a few tenths of an inch
of snow accumulation across east central Kansas. The breezy
northerly winds won`t begin to diminish until Sunday afternoon, so
decent cold air advection will persist through the day, resulting in
high temperatures only reaching into the mid 30s to mid 40s from
east to west.

A weak mid-level ridge will stretch northeastward from the
southwestern U.S. into the Central Plains on Monday with surface
high pressure in place over the region. This surface high will shift
south of the area through the day on Monday with winds shifting back
to the south, so expect temperatures to quickly rebound. Have
trended a few degrees warmer for Monday with highs ranging from the
mid 50s to upper 60s east to west. Monday night into Tuesday another
mid-level trough will track eastward across the northern Rockies and
Northern Plains, which will help to push another cold front
southward through the region on Tuesday. There are some minor model
discrepancies with the exact timing of this frontal passage, but
looks like much of east central Kansas will remain in the warm
sector under southerly flow for much of the day, so have increased
the temperature spread from the mid 50s near the KS/NE border to the
mid 60s over east central Kansas. The ECMWF is the only model at
this time suggesting the potential for some light post-frontal
precipitation late Tuesday afternoon through early Wednesday
morning, so have only slight chance PoPs in during that period. Any
precipitation that does fall would likely be in the form of rain but
may briefly transition to light snow by early Wednesday morning as
low temperatures drop to near freezing. Surface high pressure
settles into the area once again by mid week, shifting southeast of
the area by Thursday. As a result, highs should drop into the 50s
for Wednesday but rise back into the 60s for Thursday and Friday.
The GFS was showing the potential for precipitation on Friday with
another approaching cold front, but have removed the mention of PoPs
at this time due to uncertainty amongst the models.


&&

.AVIATION...(For the 18Z TAFs through 18Z Saturday Afternoon)
Issued at 1234 PM CDT FRI MAR 14 2014

Expect VFR conditions through the next 24 hours. Northwest winds
of 12 to 15 KTS with gusts to 19 to 23 KTS should diminish later
this afternoon. Southerly winds will increase to 10 to 15 KTS
after 14Z SAT.


&&

.FIRE WEATHER...
Issued at 348 PM CDT FRI MAR 14 2014

RH values at 20Z ranged from 15 to 20 percent across the CWA. Red
flag conditions were probably occurring across eastern Nemaha, Brown
and perhaps northern Jackson counties. Northwest surface winds
across the the remainder of the area have ranged from 10 to 16 MPH
with gusts of 17 to 24 MPH. The winds should gradually decrease
through the late afternoon hours.

Due to the dry fuels, low RH`s, and winds of 10 to 20 MPH with some
gusts of 20 to 25 MPH, any planned burns this afternoon and evening
may become out of control wildfires. Therefore, any planned burns
should be postponed through Sunday.

Very high fire dangers will once again occur across north central
and northeast KS. Low-level moisture advection will cause RH`s to be
higher across east central KS during the afternoon hours of Saturday.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Gargan
LONG TERM...Hennecke
AVIATION...Gargan
FIRE WEATHER...Gargan