Area Forecast Discussion
Issued by NWS Hastings, NE

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545
FXUS63 KGID 160948
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
448 AM CDT Mon Oct 16 2017

.SHORT TERM...(Today and tonight)
Issued at 448 AM CDT Mon Oct 16 2017

If you don`t mind some breezy/borderline windy conditions this
afternoon, today looks to be another in a string of virtually
"guaranteed" dry fall days, and also the first of several days
that will climb at least 5-10 degrees above mid- October normals.
Although skies should average mostly sunny for the day as a whole,
there will probably be at least scattered coverage of high cloud
cover streaming overhead mainly this afternoon- evening. Although
not expected to be a truly "big deal", there are at least "near-
critical" fire weather concerns this afternoon due to the
increased wind/warmer temps. For all further discussion of this
please refer to the separate Fire Weather section below.

Taking a quick overview of recent/current conditions:
It`s been another extremely quiet night under clear skies. In the
mid-upper levels, short term model data and water vapor satellite
imagery indicate west-northwest flow aloft, with a weak/moisture-
starved disturbance gradually approaching from the Northern
Rockies. At the surface, our local area is along the northern
fringes of a ridge centered over the Southern Plains, promoting
breezes varying from near-calm to perhaps as much as 5-10 MPH from
the south-southwest for brief spells here or there. These
differing breezes are resulting in some modest, localized
temperature fluctuations, but when all is said and done, most of
the CWA is expected to bottom out in the 33-38 range, with typical
colder spots such as Ord dropping a bit colder. We continue a
Frost Advisory through 14Z/9AM for our 6 KS counties, where the
growing season is still considered active (please refer to an
infographic posted to our web page/social media accounts during
the past 24 hours for more details regarding our approach to
frost/freeze headlines going forward, including that we are done
issuing for our Nebraska zones this fall, due mainly due to more
widespread frost/freeze event on Oct. 11).

Now briefly going over forecast details through these next 24
hours...

Today:
Once the morning Frost Advisory expires in KS zones, the biggest
questions for the day are mainly: 1) How windy does it get?...2)
How warm does it get. Compared to the previous forecast, sustained
wind speeds for this afternoon were cranked up a solid 5 MPH and
gusts more so 5-10 MPH. High temps were only nudged up slightly
(1-2 degrees). In short, a tightening pressure gradient and
increased/deeper mixing should promote sustained south-southwest
winds of at least 15-20 MPH/frequent gusts 20-25 (perhaps as high
as 30) MPH, especially between 1-5 PM. These winds mixing into a
warmer airmass aloft should result in high temps roughly 8-10
degrees warmer than yesterday, with most of the CWA aimed into the
71-75 range. Nudged up sky cover percentages somewhat for this
afternoon to account for at least a modest increase in passing
high cirrus from the west, but the day should still average mostly
sunny as a whole.

Tonight:
Another mostly clear and dry night, with the main difference from
the ongoing night being low temperatures holding up generally 5-8
degrees milder, and thus little if any concern for frost except
maybe perhaps in a few of our extreme northern/western counties
(Valley/Dawson) where the growing season is considered over. While
upper 30s will be possible in the far northwest, the majority of
the CWA should hold up in the 40-44 range. The majority of the
night will feature steady southerly breezes at least 5-10 MPH
(perhaps 15 MPH for a time far southeast), before easing up closer
to sunrise as a very weak front/trough axis slips into our area
from the northwest and brings light northerly breezes to mainly
our northwestern 1/3.

.LONG TERM...(Tuesday daytime through Sunday)
Issued at 448 AM CDT Mon Oct 16 2017

General overview of this 6-day period, including precipitation
potential:
Although this particular forecaster has only limited "history"
with the details of this time frame, at least at a glance the
bottom line appears very much the same: the vast majority of it is
seasonably-mild, dry and thus very favorable to those with
agricultural harvest interests. The overall-biggest uncertainty,
and also the only real window of opportunity for any rainfall,
involves the ultimate timing/impact of a modestly-strong cold
front that is currently slated to slice across the region on
Saturday. A few of these questions include: 1) Will any convection
develop ahead of the front on Friday night (not officially
mentioned in the latest forecast)?...2) Will rain/possible
thunderstorms Saturday along the front affect most of our area or
perhaps only brush our far eastern counties before becoming more
organized farther off to our south/east...3) Might there be the
potential for a few strong/severe storms Saturday afternoon
depending on frontal timing (nothing is formally advertised by
SPC yet given inherent uncertainty)? Given this all still over 5
days away, there are obviously still plenty of details to sort
out.

The basic upper air pattern through these 6 days:
As the week goes on, we basically continue a transition from west-
northwest flow, to a brief period of broad ridging, and then
followed by southwesterly flow late in the week ahead of the
aforementioned, fairly progressive large-scale trough slated to
track through the Central Plains mainly Saturday-Saturday night,
with ridging then again building in Sunday in its wake. Honestly,
by longer-range standards, the latest ECMWF/GFS runs are actually
in pretty impressive agreement on the large-scale features.

Temperatures:
Very little change will be noted here from the previous forecast
package, as we are looking at a solidly warmer-than-normal pattern
with highs generally around 10 degrees above normal most days.
More specifically, especially Tuesday-Friday are looking rather
similar with highs somewhere in the mid-upper 70s, and possibly
flirting with 80 far southwest. Obviously Saturday carries some
uncertainty depending on frontal timing, but at least for now
still expect highs near-70 most areas (although at least some
areas could fall in the afternoon). Very preliminarily, Sunday
features slightly cooler highs in the mid-upper 60s. As for
overnight lows, not surprisingly a solidly warmer-than-normal
story on most nights, with a lot more 40s/50s than 30s, and at
least for now, little if any concern for frost/freeze. Two of the
nights with perhaps the greatest room for adjustment versus the
current forecast include Friday night (this could trend warmer in
the southerly winds ahead of the front) and Saturday night (this
could trend colder behind the front). In fact, Friday night lows
may struggle to drop below 60 in many areas, which is pretty
impressive for this time of year.

Other concerns/issues worth mentioning:
Although especially the Tuesday-Thursday time frame looks to
feature relatively tame winds (at least by Nebraska-Kansas
standards), fairly strong southerly breezes will return by Friday
as pressure falls occur ahead of the approaching system. This will
likely then be followed by a decent surge of north-northwest winds
on Saturday/Saturday evening behind the front (perhaps similar to
what we just saw this past Saturday evening?).

&&

.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Tuesday)
Issued at 1236 AM CDT Mon Oct 16 2017

General overview:
Extremely high confidence in VFR ceiling/visibility, zero chance
of precip and only limited high level cloud cover (mainly during
the latter half). Gusty south-southwest winds during the
afternoon will be the main issue...more details follow.

Winds:
Compared to previous TAF issuance, have boosted afternoon wind
speeds several knots. Very light speeds this morning will
gradually pick up mid-late morning, and then for most of the
17-23Z time frame expect sustained around 15kt/gusts around 23kt
before easing back down to average around 10kt Monday evening.
There are hints of some marginally-mentionable low level wind
shear (LLWS) mainly around/after 03Z, but because this is so late
in the current valid period will defer to the next TAF issuance
to take a closer look.

&&

.FIRE WEATHER...
Issued at 448 AM CDT Mon Oct 16 2017

Although it may seem hard to believe given how much rain we`ve
seen this month, our recent colder night temperatures/frost and
gradually-drying vegetation signal the early stages of our
typical fall fire weather "season" that typically peaks late
October into November.

At least in the near-term, the only day of much concern is right
away this afternoon, and fortunately it looks to only be a "near-
critical" event. Putting the numbers to it, afternoon relative
humidity (RH) values look to bottom out between 20-25 percent this
afternoon across most of the CWA, at the same time south-
southwest winds are solidly gusting 20-30 MPH. It`s not out of the
question that RH values could drop a touch lower into
technically-critical territory, but given that vegetation (fuels)
is probably still a bit marginal for widespread fire growth, this
does not have the look of a situation that would warrant Warning
issuance. Nonetheless, it`s something to keep an eye on, and will
maintain a formal mention in products such as the Hazardous
Weather Outlook (HWOGID).

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...Frost Advisory until 9 AM CDT this morning for KSZ005>007-
     017>019.

&&

$$

SHORT TERM...Pfannkuch
LONG TERM...Pfannkuch
AVIATION...Pfannkuch
FIRE WEATHER...Pfannkuch



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