767 
FXUS63 KGLD 061549
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
849 AM MST Sat Feb 6 2021

.UPDATE...
Issued at 846 AM MST Sat Feb 6 2021

Reduced visibilities in patchy fog will continue across much of 
the region later than anticipated this morning. Visibilities are 
generally above one mile, but visibilities may fall down to a half
mile at times. Conditions are expected to improve by midday.

&&

.SHORT TERM...(Today through Sunday) 
Issued at 138 AM MST Sat Feb 6 2021

Latest upper air and satellite data show a long wave trough with 
three separate rounds of cloud cover moving over the Plains. Each 
one of these corresponds to a minor short wave trough. The first 
short wave trough is currently producing snow over the northern 
part of the forecast area. Visibility has fallen to as low as a 
mile at times as the brief periods of snow move through.

This morning the second round of snow will be moving across the 
northern half of the forecast area.  This round should exit the 
forecast area mid morning.  During this second wave there may be 
some freezing rain with it.  Soundings indicate the saturate layer 
becomes more shallow as the short wave trough approaches.  This may 
allow some of the snow to change to freezing rain.  However 
confidence is low this will occur.  Snow rarely changes to freezing 
rain once it starts.  Plus the top of the saturated layer is at 
-10C, which supports the majority of the cloud being composted of 
ice crystals.  WPC has high probability of freezing rain occurring, 
so decided to include a mention for a slight chance of freezing rain 
over the eastern part of the forecast area this morning.  Since snow 
will have already fallen, am expecting minimal impact if freezing 
rain does occur.

Temperatures today will be a challenge as a cold front moves into 
the forecast area behind the snow this morning.  The coldest 
temperatures will be over the northeast, with warmest to the 
southwest.  Many of the near term models indicate the current 
forecast is roughly five degrees too warm.  However, the model that 
handled this setup the best last time has highs warmer than 
consensus, so decided to go with the warmer model.  

Northwest winds will become breezy this morning behind the cold 
front as some of the winds from the low level jet mix down.  The 
winds will be strongest mid morning then decline and become light 
during the afternoon as they turn to the northeast.  

Tonight the northeast winds will turn to the southeast and become 
breezy as the surface pressure gradient tightens.  The colder air 
mass will cause lows to be cooler than last night, falling into the 
teens and low 20s.  Late in the night a weak upper level short wave 
trough will brush the northeast part of the forecast area, leading 
to minimal snow amounts.  A shallow saturate layer behind the front 
may also allow flurries to occur over the northern part of the 
forecast area.  

Sunday a surface trough pushes the cold front northeast, allowing 
temperatures to warm for the southwest half of the forecast area 
into the mid to upper 40s. Northwest winds may be breezy along the 
surface trough if the low level jet winds mix down more than 
currently forecast. 

Sunday night another upper level short wave will move through the 
flow overhead, pushing the cold front back south and causing some 
light snow and flurries to possibly occur.  Am thinking the flurries 
are more likely due to the weak lift and shallow saturated layer 
that will occur as the cold front moves through.  Lows will be 
colder than tonight due to the cold front moving back into the 
forecast area, with readings in the single digits to 15 degrees. 
Wind chills will approach -10F for the northeast part of the 
forecast area.

.LONG TERM...(Monday through Saturday) 
Issued at 106 AM MST Sat Feb 6 2021

The main points of interest for the extended period include very 
cold temperatures and a chance of light snow on Thursday.

Colder temperatures will be setting in across the Tri-State area for 
the extended period. A strong area of Arctic air moves south across 
the plains. Guidance is in decent agreement with the upper air 
pattern Monday through Wednesday as a fairly benign pattern is 
expected. We will start to see the early signs of the cold air mass 
affect the area as high temperatures will struggle to get above 30 
degrees; the northeast counties of the CWA may not even get out of 
the teens for highs on Wednesday. The main concern for these days 
will be cold low temperatures. The low Monday through Wednesday are 
expected to be in the single digits to below zero. This will also 
cause very cold wind chill values; the wind chills will need to be 
continued to be monitored as they could approach advisory level 
especially overnight Wednesday.

Starting Thursday and into the latter portion of the forecast 
period, the arctic air mass will become more noticeable as high 
temperatures will struggle to get out of the teens across the entire 
area. Thursday and into the morning hours on Friday some light snow 
is possible as some moisture will be present. The latest guidance 
runs differ on the placement of the arctic high. The GFS currently 
has the center of the high further south than the ECMWF, which if 
the GFS verifies even colder temperatures will be possible. The 
NAEFS,GEFS and ECMWF ensemble tables all show a 0.5 to minimum 
percentile 850mb temperature anomalies Thursday morning and into the 
weekend. This hint at such a strong temperature anomaly will need to 
be watched as the event draws nearer and guidance comes into better 
agreement on the overall placement of the center of high pressure. 

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 454 AM MST Sat Feb 6 2021

VFR to IFR conditions forecast for the TAFs. Confidence is on the
low side regarding ceiling forecast through 18z. Latest guidance
has KGLD potentially increasing to MVFR from IFR then back down to
IFR. Am wondering if the ceiling height will be dependent on where
the cold front ends up being this morning. The ceiling should
increase this afternoon as the cold front may move back east of
the site. For KMCK MVFR conditions may vary to VFR during a few
hour window this morning. Current observations upstream of the
site kind of support this. During the afternoon the ceiling will
fall to MVFR and eventually IFR.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

UPDATE...JBH
SHORT TERM...JTL
LONG TERM...TT
AVIATION...JTL