National Weather Service Raw Text Product

317 
FXUS64 KOUN 090006
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
606 PM CST Thu Nov 8 2018

.DISCUSSION...


&&

.AVIATION...
IFR conditions in low clouds will persist much of the night over
central and western Oklahoma with some MVFR ceilings in
southwestern Oklahoma. Clouds will clear quickly from the north
Friday morning giving moderately gusty north winds and VFR
conditions the rest of Friday.

&&

.PREV DISCUSSION... /issued 407 PM CST Thu Nov 8 2018/ 

DISCUSSION...
The primary forecast issues continue to be a widespread freeze 
expected Friday night into Saturday morning and the chance for 
winter precipitation Sunday night into Monday. 

For this evening, rain and drizzle will move to the east as the 
upper-level trough axis passes by. Temperatures are expected to 
drop below freezing across northern and west central Oklahoma 
tonight. Therefore, will maintain the current Freeze Warning that 
is in effect. 

Another cold day is expected on Friday with highs ranging from 
the low 40s F across the northeast Oklahoma to low 50Fs across 
western north Texas. These temperatures are around 15-20 deg F 
below average for this time of year. 

Friday night into Saturday morning, a widespread freeze is still 
expected with the coldest low temperatures of the season. Light 
winds, clear skies, and low dew points will provide an 
environment favorable for radiational cooling. A hard freeze 
(temperatures <=28 deg F) is currently forecast to occur across 
almost all of Oklahoma. Temperatures near the Oklahoma/Kansas 
border may drop into the upper teens. 

Expanded the Freeze Watch to include the rest of the western 
north Texas counties as forecast lows are at or below freezing in 
this area. Another cold, below- average day is expected for 
Saturday afternoon. 

For Sunday night into Monday, the ECMWF and GFS are in better 
agreement with orientation of a positively-tilted southern stream 
trough that will pass by the area. Ascent from this wave will 
result in the development of precipitation. 

Preceding the approach of this southern stream trough, a northern
stream trough will result in a cold front passing through the 
area Sunday afternoon into Sunday evening. Cold air advection 
behind this front is expected to result in a rain to snow 
transition zone as the cold air deepens.

Even though the the overall synoptic features are similar, there 
is still uncertainty where the greatest ascent and attendant 
precipitation will occur. Specifically, the GFS is more amplified 
with the northern stream trough. Consequently, the ascent and 
moisture associated with the southern stream trough is shifted 
farther south (along with the precipitation). 

The uncertainty on the trough evolution is represented by the 
large spread among ensemble data. For example, the 08/00Z ECMWF 
had a range of snow from 0" to 5.2" at Gage, Oklahoma (with an 
ensemble mean of 1.7"). The bottom line: Rain transitioning to 
snow is likely somewhere Sunday night into Monday; however, the 
location and exact amounts are too early to determine. 

Otherwise, Monday will be quite cold with steady and/or falling 
temperatures in the 30s F. Gusty northerly winds will result in 
wind chills in the teens and 20s F. The temperature forecast has 
much greater confidence than any snowfall amounts/locations. 

After another cold day Tuesday (with a widespread hard freeze in 
the morning), warmer weather is expected by Wednesday and Thursday
of next week as mid-level heights rise and southerly winds return
across the area. 

Mahale

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  33  47  24  47 /  20   0   0   0 
Hobart OK         33  51  26  48 /  20   0   0   0 
Wichita Falls TX  38  53  29  49 /  20   0   0   0 
Gage OK           29  46  25  51 /  20   0   0   0 
Ponca City OK     30  42  21  45 /  50   0   0   0 
Durant OK         41  50  29  48 /  30   0   0   0 

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Freeze Warning from midnight tonight to 9 AM CST Friday for 
     OKZ004>024-035.

     Freeze Warning from 9 PM Friday to 10 AM CST Saturday for 
     OKZ004>048-050>052.

TX...Freeze Watch from Friday evening through Saturday morning for 
     TXZ083>090.

&&

$$

23/09/09