Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 291128
Area Forecast Discussion
National Weather Service Goodland KS
528 AM MDT THU SEP 29 2016
.SHORT TERM...(Today through Saturday night)
Issued at 232 AM MDT Thu Sep 29 2016
The main forecast issue will be chance of precipitation from late
tomorrow afternoon into Saturday night. Satellite showing an
amplified flow from the Pacific into eastern North America. The flow
has become more amplified from yesterday. A large upper low centered
over Indiana continues to move slowly south with upper low near
southern California becoming more sheared out. In between these two
strong upper ridge continues to build west and north. Next upper low
is digging toward the Pacific northwest and is becoming more cut off.
Low level ridging and dry, behind backdoor cold front, has pushed
into the area.
At mid levels...the Canadian was doing better than the rest with Gfs
next in line. Main problem was models not far enough west and
amplified enough. Models were having some problems with the
surface setup. They were not strong enough and far enough west
with the ridge behind the front. The Sref followed by the Canadian
was doing the best. The models tended to be too cool on the low
level thermal field with the Sref, Canadian, and Nam the best.
For today/tonight...Initial very minor concern is the possibility of
fog over the northeast. Dry low level air is moving in from the
north per observation and 850 mb analysis. Dewpoints will be much
lower than expected mins. Believe model guidance that is showing
this is overdoing so leave it out at this time.
Model guidance from yesterday was way too cool on maxes, especially
in the western and northern sections. Again should have plenty of
sun to help temperatures rise. It does look to be cooler since not
as much mixing looks to occur today. Dry air mass will allow the
temperatures to rise decently. Tended to go near to slightly above
guidance. Per pressure gradient and 3 hour pressure falls, southerly
winds will be near breezy to breezy, mainly in the west.
Once again guidance is showing the possibility of fog. At this
time do not feel confident enough to include for now.
For Friday/Friday night...per reasoning above will leave out any
mention of morning fog. Surface focus stays to the west of the area
through the period. Mid/upper level ridge remains strong over the
area per the slow movement of the large upper low over the eastern
portion of the conus. So as indicated yesterday, this keeps the lift
and moisture further west. Model/wpc qpf is also further west than
what was shown yesterday, especially the Canadian and Gfs which have
the strongest ridging aloft which synoptically makes sense. So have
no problem keeping this period dry. The Nam appears to be suffering
from convective feedback during the night.
Per plenty of sun and recent model biases/performance, have kept
high temperatures near to slightly above guidance. For the night the
probabilities for fog look low so will continue to keep it out.
For Saturday/Saturday night...Am a little concern about this period.
Moisture/precipitable water increases during this period with good
lapse rates moving in as well. The problem is lack of strong/deep
lift. Surface focus remains west of the area until late in the
night. The mid level ridge breaks down through the day. A weak
shortwave comes through/across the top of the ridge and looks to
affect the eastern third to half of the area from the very late
afternoon into the overnight hours. At this time just have slight
chance pops due to the lack of lift. However if it looks like more
lift will be available then the pops will have to be raised. Also
the stronger storms could produce moderate to locally heavy rainfall.
Looks to be more cloud cover this day although not terribly thick
cloud cover. At this time think that it will not affect temperatures
much. Per recent trends/biases, I went toward the warmer guidance.
Nams temperatures are cooler because of convective feedback issues.
.LONG TERM...(Sunday through Wednesday)
Issued at 205 AM MDT Thu Sep 29 2016
High pressure ridge will move across the Plains on Sunday with a
deep trough and associated area of low pressure approaching from the
west. Dry conditions will prevail on Sunday with above normal
temperatures as the ridge is pushed off to the east. The low will
move across the Great Basin and into the central Rockies as we head
into Monday with Moisture levels increasing as the 850mb winds
continue out of the south to southwest. The cold front associated
with the low will approach the western portions of the CWA on
Tuesday by around midday with PoPs increasing mainly for areas east
of the Kansas/Colorado border as the front pushes across the area
through the course of the day. There will be marginal instability
and CAPE in the eastern half of the CWA with decent low level shear
Tuesday afternoon and evening thus will need to monitor closely for
the possibility of isolated strong to severe thunderstorms.
The front will move through the remainder of the CWA overnight with dry
weather expected after sunrise on Wednesday. Highs will top out in
the upper 60s to near 70 degrees on Wednesday behind the front. We
could see another round of patchy frost Wednesday night as
temperatures drop into the upper 30s with dew points in the upper
20s to near 30 degrees.
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 525 AM MDT Thu Sep 29 2016
Vfr conditions are expected through the period. At Kgld...by late
morning, light southerly winds will increase to near 14 knots with
gusts to around 23 knots. Around 01z the gusts stop with sustained
winds between 10 and 15 knots. At Kmck...around late morning light
and variable winds become southeast between 5 and 10 knots. These
winds continue through the rest of the period.