Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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000
FXUS64 KOUN 292032
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
232 PM CST Tue Nov 29 2016

.DISCUSSION...
12z upper level analysis shows a very broad/deep and increasingly
occluded low centered over Minnesota. Strong westerlies extended
from the Pacific Northwest region through the Southwest and across
the southern Great Plains into the Northeast. Our morning sounding
at Norman sampled 145 knots at jet level. One in a series of
embedded shortwaves approaching us has forced a cold front
southward through our area, bringing slightly cooler temperatures.

Our weather through the rest of the week should generally be
uneventful as deep closed low moves east and flow aloft is zonal,
or at least quasi-zonal. Very subtle low amplitude ridging on
Thursday may be enough for temperatures to warm slightly with a
few locations across the southern portion of the area reaching
into the lower 60s for highs. A few periods of cirrus streaming in
from the west may be observed Thursday and especially by Friday as
westerlies aloft strengthen and back in response to an evolving
deep trough across the western United States.

Uncertainty for the precipitation event late Friday through the
weekend has decreased. A fairly high confidence isentropic
ascent/warm advection precipitation event is expected Friday
evening and overnight, starting in western north Texas and
expanding northward and eastward through Saturday morning.
Conceptually, this warm advection regime is not typically
associated with winter weather unless antecedent conditions are
particularly cold/dry. Trends in raw guidance have been for warmer
temperatures and forecast soundings show wet bulb profiles that
are generally favorable for rain. We have trended temperatures
toward this raw guidance and away from bias corrected guidance
which can be too low in these scenarios. The potential for a
period of snow mixing in across northwest Oklahoma is still
present given the thermal profile seen in the forecast soundings but
an impactful winter weather scenario is not expected. We have
further confined the time/space of rain/snow mix across northwest
Oklahoma, and if trends continue, may be able to remove it
altogether keeping just rain.

We have limited the highest precipitation probabilities to the
southwest portion of the area Friday night where isentropic ascent
and moistening is more pronounced on 290-300k surfaces. The
higher probabilities were spread eastward across the southern half
of the area Saturday and diminishing from northwest to southeast
through early Sunday. With much better agreement among medium
range guidance, we were able to remove precipitation for a portion
of the area Sunday and the entire area Sunday night. A second area
of ascent as the trough opens up and ejects northeast may bring
another round of light rain to mainly the eastern portion of the
area on Monday.

BRB

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  32  55  30  60 /   0   0   0   0
Hobart OK         31  55  30  58 /   0   0   0   0
Wichita Falls TX  35  58  34  62 /   0   0   0   0
Gage OK           27  53  22  54 /   0   0   0   0
Ponca City OK     30  53  26  57 /   0   0   0   0
Durant OK         37  57  35  62 /   0   0   0   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

$$

17/12



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