Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 270534
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
1234 AM CDT Thu Jul 27 2017

.SHORT TERM...(This evening through Thursday night)
Issued at 403 PM CDT Wed Jul 26 2017

After receiving beneficial rain across much of the area overnight
through the morning hours, cloud cover and below average temps
persisted through the day. However, a narrow break in the clouds
has allowed for some areas to reach into the upper 80s and low
90s. A slow to exit low and associated cold front remain situated
across the area this afternoon with scattered rain showers and
thunderstorms continuing to slowly drift to the east and
southeast.

This activity has remained below severe limits at this time.
Uncertainty remains on whether or not any of this activity will
become strong to severe. The narrow band that extends from
Hastings to Lincoln is entering a region of warmer temps and
increased instability due to a rather persistent narrow break in
the clouds, so it seems reasonable that at least a strong storm or
two could develop with 40 to 50mph wind gusts and nickel sized
hail being the main hazards. Given the slow movement of these
storms locally heavy rainfall will also be possible.

Although scattered redevelopment could occur across much of the
area into tonight, any lingering showers should exit the area
overnight with skies beginning to clear Thursday morning. Although
today was technically "cooler" for some areas, Thursday looks to
be the first "nice" day of what looks to be the beginning of a
stretch of below normal temps across the area with highs in the
80s.


.LONG TERM...(Friday through Wednesday)
Issued at 434 PM CDT Wed Jul 26 2017

General overview of this 6-day period: For those perusing our
long term discussions over the past 24 hours, you will find little
noticeable change in the messaging. It continues to be the case
that: 1) Each one of these days features remarkably similar, near-
to- slightly BELOW normal/average temperature expectations with
highs mainly in the mid-upper 80s and lows mainly in the low-mid
60s. 2) Literally each day night/period from Saturday onward
features at least a small chance (PoP) for rain/thunderstorms
within some portion of our county warning area (CWA). That being
said, none of these chances carry very high confidence in how they
may/may not pan out, as we are entering a semi-persistent and
tricky-to-forecast- rain weather pattern featuring a quasi-
stationary ridge over the western CONUS, a broad trough over the
eastern CONUS, and "us" in between under rather persistent west-
northwest flow mid level flow aloft featuring the passage of
various low-amplitude disturbances/shortwave troughs.

Some more thoughts more regarding temperatures/dewpoints: Again
want to make it clear that we are not talking a transition to a
"refreshingly" cool/dry airmass by any means, but more so simply a
respite from the frequent highs/heat index values well into the
90s/100s on many recent days. It is still mid-summer after all,
and it will still feel like summer, albeit with somewhat less
humidity than late with dewpoints more solidly down in the 60s
versus the more oppressive 70s that have been common especially
within our Nebraska zones on many recent days.

Some more thoughts on rain chances/thunder intensity: While the
majority of advertised PoPs are currently only in the 20-30
percent range, there are some higher values as high as 50 percent
in our southern/southwest zones mainly late Saturday night into
Sunday. However, want to caution that these seemingly higher
chances are from holding true to reality, as they could reflect
some "convective feedback" in the 12Z GFS model as much as
anything truly real. In addition, want to point out that even our
fairly low PoPs from Monday into Tuesday currently don`t have much
support from either the GFS or the ECMWF, but instead are likely
tied mainly to what appears to be an unusually (overly?) wet 12z
Canadian model, which is one of the models that go into our
"Superblend" that initializes most of the Day 2-7 forecast. The
bottom line is this: On many days, the forecast probably sounds
"wetter" than it actually will be. As for severe thunderstorm
chances, although it`s almost impossible to rule out a "Marginal
Risk" type setup or two in this pattern, there is certainly
nothing that stands out as obviously-concerning at this time, and
we will just have to take a closer look at a few of these setups
as they get closer and the details become a little clearer.

With the main points covered, will conclude with some brief day-
to- day specifics for those interested...

Friday daytime-night: These are the only two long term forecast
periods that currently carry a dry forecast CWA-wide, as we
feature a pronounced lack of convective instability and also
continue to remain under the dominant influence of a glancing blow
of Canadian high pressure in the low-levels. While confidence is
quite high in the dry daytime forecast, the late night hours are a
little more questionable and bear watching, as some showers/weak
storms "could" perhaps try creeping into some of our
northern/western zones late in the night. Otherwise, the day
should be mostly sunny with east-southeast breezes around 10 MPH.

Saturday daytime-night: Here begins the multi-day "parade" of
fairly low-confidence rain/thunderstorm chances, but don`t go out
of your way to change any outdoor plans yet. Also, Most of these
chances favor the western half of the CWA versus the east. Breezes
mainly from the south-southeast behind the departing ridge axis.

Sunday-Wednesday: Very much the same story continues throughout
all 4 of these days, with off-and-on rain/thunderstorm chances but
nothing that looks overly-solid. The very consistent temperature
regime also continues, with highs mainly mid-upper 80s.

&&

.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Thursday)
Issued at 1234 AM CDT Thu Jul 27 2017

Significant Wx: MVFR or IFR fog possible thru 13Z.

Overnight: MVFR fog has developed at GRI and IFR fog is already
nearby at AUH/JYR. MVFR fog should make it to EAR with potential
for IFR at GRI. Not sure how bad it will get but consensus of
model guidance suggests vsbys should remain above 2SM. Drier air
will be working in from the NE and that should mitigate LIFR or
VLIFR fog. Lgt NE winds. Confidence: Medium

Thu: Any fog should dissipate by 13Z leaving VFR with no clds AOB
10K ft. NE winds around 10 kts. Confidence: High

Thu Eve: VFR with no clds AOB 10K ft. Lgt E winds. Confidence:
High

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&

$$

SHORT TERM...Petr
LONG TERM...Pfannkuch
AVIATION...Kelley



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