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Area forecast discussion
National Weather Service Topeka Kansas
525 PM CST Mon Nov 18 2019

..update to aviation forecast discussion...

Short term...(this evening through tuesday)
issued at 258 PM CST Mon Nov 18 2019

Recent water vapor imagery showing northwest flow from the
Pacific northwest into the southeast states with a few stronger
perturbations/pv anomalies making their way across the Missouri
Valley. Above-normal precipitable water values were noted on
nearly all 12z central and northern plains soundings with much of
saturation in the mid and upper layers and this combined with mid-
level lapse rates near 6.5 c/km were allowing for some areas of
scattered precipitation to pass through, though only trace amounts
were reported. Deep mixing in the wake of the modified front,
located in far eastern Kansas early this afternoon, was bringing
temperatures up to around 70 f in much of central and western
Kansas, with gusts around 40 mph in central Nebraska.

Upper ridging builds east into The Rockies tonight, with the
stronger northwest flow shifting away. Clearing skies early this
evening should allow for a decent inversion to develop and keep
the gusty winds to the northwest from impacting the local area.
The stronger winds above the boundary layer should mitigate
anything more than isolated steam fog formation in locations
protected from west to northwest winds late tonight into early
Tuesday morning. Another warm day is on tap for Tuesday despite
modest winds in the 1012 mb surface ridge with only some temporary
bands of mid and high clouds passing.

Long term...(tuesday night through monday)
issued at 258 PM CST Mon Nov 18 2019

A moderate south-southwest low-level jet develops Tuesday night
under briefly zonal cross-rockies flow as multiple upper waves
enter the southwestern states. With some increase in cirrus
likely, low temperatures should only fall in the 40s. After a
brief fall in levels tonight and Tuesday, precipitable water values ramp up to
near-record levels late Wednesday into Wednesday night as the
first upper wave quickly moves northeast. Light to at most
moderate rainfall amounts are likely however given the quick
nature of this wave. There continues to be indications of lapse
rates returning to near 7 c/km in the moisture for some elevated
convective potential for the afternoon and night. Cold air
advection behind the associated front is again modest and even the
coldest solutions keep temperatures above freezing and prevent a
wintry precip concern from materializing.

The evolution of the second wave remains very uncertain as it
attempts to cut off from the split flow. The 12z GFS and most of
its ensembles along with the 12z European model (ecmwf) are much weaker and faster
with the wave, however some light precipitation remains possible
with the weakening wave Friday and Friday night, with continued
cold air advection allowing for some various precip types. Overall the confluent
pattern does not favor anything more than a modest winter event.

Split flow continues through the weekend into early next week with
moderating temperatures on tap. There is fairly good agreement in
a shortwave digging into the central rockies just beyond this
forecast however.

&&

Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 511 PM CST Mon Nov 18 2019

Isolated showers are possible for the next 1-2 hours, primarily in
far northeast Kansas where better lift resides. Low level winds are
likely to increase up to 40 kts at 1000 ft as they veer to the
northwest behind the frontal passage. Inserted the mention of low level wind shear at all
sites aft 02-03z, diminishing as the sfc high builds in the 07-08z
time frame. VFR will prevail throughout the forecast period.

&&



Top watches/warnings/advisories...
none.
&&

$$

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