Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 191029

Area Forecast Discussion
National Weather Service Hastings NE
529 AM CDT Thu Apr 19 2018

.SHORT TERM...(Today and tonight)
Issued at 317 AM CDT Thu Apr 19 2018

High pressure is beginning to nudge in across the local area as
the remaining cloud cover from yesterdays disturbance continues to
thin and track east of the local area. At the same
time...generally light winds have overtaken the region overnight
as an area of high pressure has been sliding south across the
central plains early this morning. While a few sites still have
northerly winds near 10 mph...expect all areas to become light and
variable around daybreak...which should allow temperatures to
drop off a few more degrees over the next several
hours...resulting in a frosty start expected for just about the
entire forecast area.

With mostly clear skies and heights building aloft today...expect
a more pleasant afternoon across the region with winds less than
10 mph...ample sunshine...and high temperatures climbing into the
mid 50 to mid 60s in spots. In fact...with these conditions
setting up...actually increased high temperatures at most
locations a few degrees. While still about 5 to 10 degrees below
seasonal norms...this afternoon should feel quite nice compared
to the weather we have experienced as of late.

For tonight...warmer air advecting in from the south along with
variable high cloud cover...should make for a bit more mild
night...albeit still chilly...across the region ahead of the next
upper level low which will begin to spread its influence across
the central/southern plains Friday.

.LONG TERM...(Friday through Wednesday)
Issued at 317 AM CDT Thu Apr 19 2018

General overview of this 6-day period:
Third night examining the extended periods, and overall things
remain almost eerily consistent from 24 hours ago (very few forecast
changes unless you dig really deep). Although there continue to be
two windows of opportunity for rain (NOT snow) over the course of
these 6 days, the weather overall remains remarkably quiet for late-
April, and our Hazardous Weather Outlook (HWOGID) remains void of of
any "typical" content often seen this time of year (no thunder, no
strong winds, no fire weather etc.) The two main stories of the
extended periods also remain the same as seen here 24 hours ago:

1) There are still two main chances for rain/rain showers, the first
from Friday into Saturday as a slow-moving upper low traverses
eastward through mainly the southern Central Plains/Southern Plains,
and the second a quicker-hitting shot for passing showers during the
Mon night-Tues time frame associated with a shortwave trough
swinging east-southeast across our region, attendant to a larger-
scale trough centered well to the north, mainly over Canada.
Meanwhile, all other days (Sun/Mon/Wed) continue to carry a pretty
high confidence in remaining dry. Focusing on the nearer-term Fri-
Sat system for the remainder of this paragraph, we continue to
emphasize that this does not look like a "big soaker" by any means,
but instead a 24-36 period featuring plentiful clouds, perhaps only
isolated to scattered showers at best in our east-northeast
counties, but a better chance of some organized light to moderate
rain bands in our western-southwest zones (which probably need the
rain a bit more anyway from a drought perspective, especially KS).
Our latest official QPF/rain amount forecast ranges from only about
0.05-0.20" for the northeast half of the CWA, and more so 0.25-0.60"
in the southwest half. In other words, anybody expecting a solid
inch or so out of this will more than likely be disappointed,
especially if they haven`t stayed in tune with the downward-trend in
overall rain-amounts over the past few days.

2) Temperature-wise, we continue to average on the cooler side of
normal nearly every day (normals for late April are generally highs
mid-60s/lows mid-30s to around 40), but for sure not nearly as cold
as several recent days have been. We are also not looking at any
major temperature fluctuations either. The overall-coolest day looks
to be Saturday (largely due to clouds/rain), with highs only low-mid
50s most areas, while the overall-mildest day still looks to be
Monday with mainly mid-60s/perhaps a few upper 60s. So again, not
too cold but not too warm either. In some ways, the bigger
temperature story lies in the overnight lows, as each one of these 5
nights looks to hold up mainly in the mid-30s to low-40s range, by
far our longest stretch of above-freezing nights yet this spring.
Given that this should help to give our growing season a boost from
its slow start, it`s certainly possible/likely that if and when our
next legitimate threat for widespread frost/sub-freezing temps
finally arrives beyond these next 7 days, that formal Frost/Freeze
headlines would be issued (especially if this doesn`t occur until
after May 1).

Will now finish up with some day-to-day details for those

Friday/Friday night: Most importantly, want to emphasize that there
is a good chance the majority of our CWA gets through the daylight
hours dry, with only plentiful cloud cover and maybe a sprinkle at
most. The main exception lies within roughly our western 1/4 (such
as Dawson/Furnas counties), where the mid-upper low approaching from
southern CO should get close enough during the day to promote a
fairly decent chance of showers, especially during the afternoon. At
the surface, it will be a bit breezy, with generally southeast winds
averaging 10-20 MPH with gusts to around 25 MPH. Temp-wise, if
anything we may be aiming a touch optimistic (especially far west),
but made little change with a modest range from low-mid 50s west to
upper 50s-low 60s east-southeast. On Friday evening/night, the
center of the aforementioned upper system will progress to around
the CO/KS/OK border area, increasing lift/rain chances into our CWA,
but with the overall-highest potential/PoPs focused within our
southwestern 2/3 or so. With plentiful clouds around, low temps
should not drop below the upper 30s-low 40s.

Saturday/Saturday night: Although there are signs of a possible
secondary mid level low tracking as far north as northern KS, most
models clearly take the heart of the large-scale system more so
across OK over the course of these 24 hours, focusing the heaviest
rain at least slightly to our south. That being said, pretty decent
chances for at least light rain linger especially in our
southern/western zones, and especially during the morning, before
chances gradually diminish during the afternoon/evening and should
largely end altogether by midnight. As already discussed, this looks
to be the overall-coolest day of the 7-day forecast with highs only
low-mid 50s.

Sunday daytime-Monday daytime: These 36 hours continue looking dry,
as at least a weak-modest shortwave-ridging regime overspreads the
Central Plains in the wake of the departing low that heads into the
southeast CONUS. This should result in what will likely be two of
the milder upcoming days (especially Monday). Sunday looks to have
fairly light winds and highs around 60, while Monday sees an
increase in southerly breezes. Highs Monday are officially aimed
into the mid-60s most areas, but raw numerical guidance (especially
the GFS-based MEX) suggests that many places could threaten 70,
assuming of course that clouds aren`t more abundant than currently

Monday night-Tuesday daytime: These 24 hours feature our next chance
for passing rain showers (at this point instability progs look too
low to support thunder), as the southern edge of a shortwave trough
brushes by. As was the case 24 hours ago, and not surprisingly at
all given typical model biases, the GFS solution is a bit faster and
favors the best rain chances Monday night, while the slower ECMWF
focuses more so Tuesday daytime. Given this is still several days
out, the official forecast essentially splits the difference and
places the highest chances late Mon night into Tues AM. No matter,
Tuesday will almost surely be 5-10 degrees cooler than Monday with
highs mainly in the 50s, and will likely also be rather breezy from
the north behind a passing cold front.

Tuesday night-Wednesday: The official forecast remains dry in the
wake of the departing system, and this especially appears the case
per the ECMWF, although the latest GFS is more suggestive of some
additional rain chances skirting very close to our southern edges.
Obviously these sort of model disparities are VERY common at the Day
7 range. Temp-wise, highs are preliminarily aimed into the low 60s
most areas, roughly 5 degrees warmer than Tuesday.


.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Friday)
Issued at 512 AM CDT Thu Apr 19 2018

VFR conditions are expected through the period as only some
passing high clouds are anticipated across the region as a ridge
of high pressure moves overhead. At the surface...high pressure
also resides this morning...and mainly light and variable winds
are anticipated through the daytime hours until this ridge shifts
further east and southeasterly return flow near 10 KTS develops
across the local area.




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