Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 222325

Area Forecast Discussion
National Weather Service Norman OK
625 PM CDT Thu Mar 22 2018

Aviation discussion for the 00 UTC TAFs is below.


VFR conditions are expected to continue.

MVFR ceilings are possible southeast of KLTS-KPNC 10-20 UTC
Friday, but did not mention due to low confidence of occurrence.

Non-convective low level wind shear is possible 01-16 UTC Friday,
but was not mentioned due to low confidence of occurrence.



.PREV DISCUSSION... /issued 357 PM CDT Thu Mar 22 2018/

The main focus continues to be fire weather conditions in the
short term and heavy rainfall potential in the long term.

Mean ridging has brought warmer than normal temperatures to the
area for this time of year. Tomorrow will be even warmer as flow
veers somewhat and transports deeply mixed/downsloped air from the
southwest into the area. Strong capping EML will advect atop
moistening boundary layer. Given the cap strength, it will take
more than subtle ascent expected with transient low amplitude
shortwave trough for convection to develop. So we have kept the
forecast dry from now through Saturday.

By Sunday, and into next week, western trough will dig into the
Southwest and eventually close off with little eastward progress.
Increasingly meridional flow will transport anomalous moisture
into the area. Until flow backs in response to this wave, it may
be difficult to have much in the way of deep convection and heavy
rainfall given residual capping atop increasingly deepening low-
level moisture, but eventually this should lessen in this pattern
and periods of showers and thunderstorms will occur. We have the
highest probabilities on Monday through Wednesday, after which
some medium range guidance shows phasing of mid-upper low with
northern stream and kicks it east, while other guidance closes it
off and shifts it to lower latitudes while sweeping northern
trough through. Either way, there seems to be a trend toward a
drier pattern by late week.

The best chance of sufficient instability for at least
isolated/marginal severe will be Monday into Tuesday before
stronger meridional flow and deeper saturation temper instability


Dry return flow today has resulted in some locally elevated fire
weather conditions, particularly across north central Oklahoma
into eastern Oklahoma. Once deep mixing started it was difficult
for moisture to advect into this region as some short term model
guidance suggested. Given southerly winds around 20 mph with
higher gusts at some locations, we issued a Fire Danger Statement
for portions of the area. This will expire early this evening.

Mid-level speed max at the base of transient central Plains
shortwave will pass through tomorrow, and momentum transfer may
help mix the dryline eastward into and through portions of
northwest and west-central Oklahoma. There is some uncertainty in
how far east the dryline will mix, so we decided to continue the
Fire Weather Watch and not upgrade. But an upgrade by tonight at
the latest is likely for at least portions of the Watch area. We
may confine it more to northwest Oklahoma if trends in the
observational data suggests and/or the more westward placed (with
the dryline) guidance seems most reasonable.



Oklahoma City OK  57  81  57  77 /   0   0  10   0
Hobart OK         57  88  54  79 /   0   0   0   0
Wichita Falls TX  58  86  60  82 /   0   0   0   0
Gage OK           53  93  49  75 /   0   0   0   0
Ponca City OK     55  81  53  72 /   0  10  10   0
Durant OK         55  75  63  81 /   0  10  10   0


OK...Fire Weather Watch from Friday afternoon through Friday evening
     for OKZ004>006-009>011-014>016-021-022-033-034.



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