Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 270523
Area Forecast Discussion
National Weather Service Goodland KS
1123 PM MDT Wed Apr 26 2017
.SHORT TERM...(This evening through Thursday)
Issued at 307 PM MDT Wed Apr 26 2017
Main forecast issues will be ongoing Frost Advisory and when to
start precipitation during this period. For tonight...all model
output is showing an increase in mid and high level cloud cover
through the night, especially in the northern portions of the
advisory area. Winds and temperatures still look to be the lightest
and coldest in the advisory area. So saw no compelling reason to
change the Frost Advisory. Also due to the deep dry layer in place
and high resolution output much drier than yesterday, removed
precipitation mention from tonight.
For Thursday...There is a rather deep dry layer during the morning
hours. The column moistens up in the afternoon. Models differ on the
exact location of where the mid level circulation ends up tomorrow
afternoon and its evolution. The models would indicate that the lift
will be disorganized.
For the afternoon, depending on which model you choose, there is a
surface low near the southern end of our area with either a cold
front/weak surface over our west with a warm front nosing into our
southeast/east central portion of the area. Models have theta-e
lapse rates becoming negative late in the morning into the afternoon.
Models show little to no qpf in the morning and can understand that
with what the forecast soundings show with the dry layer. However,
ended up starting pops a little sooner due to my neighbors starting
things earlier, which is possible. So increased pops from later in
the morning into the afternoon with highest pops later in the day.
Of concern is the very good lapse rates and cold pool aloft due to
the 700 mb low on top of us. That and instability/index parameters
would indicate that the storms that do develop could become strong.
Update to the Day 2 outlook shows a marginal risk near the area. Due
to the above reasoning will update the HWO to reflect this thinking.
Of minor note, high temperatures have the potential to be cooler
than what I have due to the rather thick cloud cover beginning
earlier in the day and the developing precipitation.
.LONG TERM...(Thursday night through Wednesday)
Issued at 245 PM MDT Wed Apr 26 2017
The main focus of the extended period will be the chances for
precipitation and colder temperatures Thursday night through Sunday
Thursday night: Thunderstorms and rain will be widespread through
the evening. Some storms could be strong, but not expecting anything
severe at this time. May see some of the rain change to snow in the
pre-dawn hours across western portions of the CWA. No snow
Friday-Friday night: The models have come into better agreement in
regards to this weekend`s system. A strengthening closed low will be
dropping south from Wyoming into the Four Corners region and will
then be moving across Kansas from the southwest to northeast as it
deepens. There will be rain chances across the region beginning
Friday around noon lasting through the evening. There could be a few
rumbles of thunder in Yuma County during the afternoon. Rain changes
to snow or a rain/snow mix from west to east for the most of the
region overnight. Heaviest amounts of snow are expected along and
west of Highway 27 where some blowing snow may also occur through
the early portions of the morning.
Saturday-Sunday: Areas along and south of the I-70 corridor will see
the best chance of snow in the morning. There will be periods of
snow, rain and snow, and rain throughout the day across the CWA.
The question will be how much we warm up during the afternoon. 12Z
GFS soundings show the possibility of precip staying mostly snow
through the entire day west of Highway 27 which would mean higher
snow totals than what are currently forecasted. Precip changes
back to snow during the overnight with the axis of heaviest precip
shifting along and southeast of a Norton-Gove line as the upper
low begins to pull off to the northeast. Am expecting lighter
amounts than what will occur Friday night. Slight chances of
precip linger for the eastern half of the CWA until near sundown
Current forecasted snow amounts (surely to change by the weekend)
call for areas along and south of I-70 to receive 2-4 inches, with
portions of our Kit Carson and Cheyenne(CO) counties seeing upwards
of 5 inches. Areas north of I-70 are forecasted to receive anywhere
from a few tenths to 2 inches.
As for temperatures, the entire area will see below average temps
from Thursday through Sunday night. Saturday will be the coldest day
with highs struggling to get into the 40s. MOS guidance is showing
temperatures below 28 degrees for portions of our CO counties.
Monday-Wednesday: Temperatures warm back to near normal levels
through the period. There looks to be a chance of rain Tuesday
afternoon into Tuesday night as a positively tilted shortwave
approaches the area.
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1123 PM MDT Wed Apr 26 2017
Scattered sprinkles/virga moving out of northeast Colorado tonight
will not impact flight categories. Mid and high cloudiness will
gradually increase through the overnight. Scattered showers and
isolated thunderstorms will develop across northeast Colorado and
adjacent parts of northwest Kansas Thursday afternoon, potentially
impacting KGLD. Instability will decrease towards KMCK, so
expecting mainly showers/light rain there by mid to late Thursday
afternoon. Ceilings will lower at both terminals Thursday night
with IFR conditions possible.
KS...Frost Advisory until 9 AM CDT this morning for KSZ003-004-016.
NE...Frost Advisory until 9 AM CDT this morning for NEZ080-081.