Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 200910
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
310 AM CST Tue Feb 20 2018

.DISCUSSION...A cold front draped across the northern Panhandles
is bringing temperatures in the upper teens to lower 20s in the
northern Panhandles, to the 50s to near 60 in the southern
Panhandles. Suffice it to say, this forecast is going to be quite
difficult as there is a great disparity between high-res guidance
and operational models, with poor initialization of the front by
nearly all models.  Lee side troughing, still active in New
Mexico this morning, may help keep southwesterly winds going
across the southwestern Panhandles, which could slow forward
progress of the arctic front. Given the tendency for model
guidance to project forward progression of this front to be too
slow, have opted to forecast all but the southwestern third of
the Texas Panhandle this afternoon being affected by cold air. The
airmass behind the front may saturate given low dew point
depressions, which could cause stratus to form in the wake of it`s
passage.

Attention turns toward Wednesday night into Thursday morning as
return southerly flow aloft may bring isentropic lift along the
frontal boundary. There is a decent chance of mixed wintry
precipitation in the form of snow, ice pellets and freezing rain
across the eastern Panhandles. The question remains as to how deep
of a warm nose may exist, as some guidance presents a warm nose
around 3k to 5k AGL as precipitation falls into the surface
boundary layer. Considering that water droplets may not be
supercooled as it impacts the surface, have collaborated with
neighbors about precipitation types late Wednesday and Thursday
morning. Monitoring of this situation is necessary given the
potential for a glaze of ice in the eastern half of the region if
the warm nose is more favorable than present projections.

During the afternoon on Thursday into Friday, southwesterly flow
will increase across the New Mexico Rockies that will help bring
warmer and drier conditions to the region. Drier conditions will
persist through next Tuesday before a possible incoming western
trough brings back moisture to the southern Panhandles. At this
point, have held with low end slight chance due to agreement
between the GFS and ECMWF. We`ve been here before, but one can
tell that a pattern shift may be in the offing early next week if
present projections hold.

Bieda

&&

.AVIATION...Previous Discussion...
For the 06Z TAFs, based on some latest model guidance, have
decided to speed up the cold frontal passage for all terminal
sites for this fcst cycle. This is reflected in an earlier wind
shift to the north and northeast at KGUY, KDHT, and KAMA compared
to previous fcst. Have also brought in solid MVFR cigs at KGUY and
near MVFR cigs at KDHT later tonight into Tuesday morning. No
precipitation is expected through late Tuesday night. Have kept
KAMA VFR through the end of this fcst. There remains low
confidence in how well the above scenario plays out, and
amendments may become necessary.

Andrade

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                49  21  30  22  47 /   0   5  20  10  20
Beaver OK                  35  13  31  21  40 /   5   0  20  10  30
Boise City OK              33  11  29  17  49 /   5   0   5   5   5
Borger TX                  40  21  31  23  46 /   0   0  20  10  20
Boys Ranch TX              48  19  34  21  54 /   0   0  10  10  10
Canyon TX                  62  21  33  23  47 /   0   5  20  10  20
Clarendon TX               57  25  33  24  41 /   0   5  40  10  30
Dalhart TX                 43  17  31  19  52 /   0   0  10   5  10
Guymon OK                  36  14  30  20  48 /   5   0  10  10  20
Hereford TX                63  21  35  23  53 /   0   5  10  10  20
Lipscomb TX                35  16  31  22  39 /   0   0  30  20  30
Pampa TX                   39  18  31  22  44 /   0   0  30  10  30
Shamrock TX                45  24  34  25  39 /   0   0  40  20  40
Wellington TX              56  27  37  27  38 /   0   0  40  20  50

&&

.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.

&&

$$

14/98



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