Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 10/04/19

Area Forecast Discussion

National Weather Service Hastings NE

 757 PM CDT Thu Oct 3 2019

...Aviation Update...

.SHORT TERM...(This evening through Friday)
Issued at 246 PM CDT Thu Oct 3 2019

Aloft: Moderately-amplified SW flow cont over the Cntrl Plns per
aircraft wind data...RAP dynamic tropopause analyses and WV
imagery. The anomalous subtropical high that dominated the entire
month of Sep remains over the SE USA...while the next shrtwv trof
was moving onshore in the Pac NW. Heights were rising over NEB/KS
as a shrtwv ridge was building in advance of the Wrn trof. This
ridge will crest over the CWA tonight as the trof moves inland.
Heights will begin to fall tomorrow as the flow becomes SW and the
trof conts E thru the Nrn Rckys.

Surface: 1028 mb high pres stretched from ND-NEB. The next cool
front was moving onto the W coast...associated with the next upr
trof. The high will drift into MN/WI tonight while the cool front
advances thru the Pac NW into the Nrn Rckys. The high will cont
into the GtLks tomorrow...while the front moves E from MT-WY-NV.
The pres grad will incrs over NEB/KS tomorrow between the
strengthening high and deepening lee trof.

Rest of this afternoon: Mostly sunny acrs most of S-cntrl NEB and
partly cldy N-cntrl KS. Very very nice/comfortable with cool
temps and light winds. Highs 59-64F will occur around 21Z.

Tonight: Mostly clr to start. Just some patches of cirrostratus
streaming over the SE 1/3 of the CWA initially. Overall...
gradually incrsg clds. Satl shows mid-lvl clds 7-8K ft over Wrn
KS. These clds will move NE and overtake the entire area. Isolated
to sct shwrs will be psbl after 05Z...mainly over N-cntrl KS.

Not as cold as this AM...but still maintained some 30s from ODX-
OLU consistent with the 4 AM fcst. Can`t rule out a bit of frost
here and there in sheltered valleys of Valley/Greeley counties.
Clds will be incrsg and that will mitigate this being a sig risk.

Fri: Cldy with sct shwrs. With thick cld cover all day...went
with the coolest mdl blend available. Temps should not get out of
the 50s. Winds will incrs and become brzy from the SSE...15-25
mph...espcly W of Hwy 281.

.LONG TERM...(Friday night through Thursday)
Issued at 246 PM CDT Thu Oct 3 2019

Aloft: The potent shrtwv trof over the Nrn Rckys Fri will cross
the Nrn/Cntrl Plns Sat AM...leaving a broad trof into Sun. A
weaker shrtwv trof will move thru Sun shifting winds to NW. Low-
amplitude NW flow will cont over NEB/KS Mon. Yesterday there was
quite a bit of mdl spread over the E Pac and Wrn USA for early
next wk...but the last 3 runs of GFS-FV3/EC/CMC/UKMET have come
into much better agreement. Another potent shrtwv trof over the
GlfAK will drop SE into the Pac NW Tue. Winds over NEB/KS will
become cyclonic from the WSW Tue and then SW Wed as this trof
advances into the Nrn Rckys.

Surface: The Nrn Rckys cool front will emerge onto the Plns Fri
night and cross the CWA around daybreak Sat. Weak high pres will
quickly follow over NEB/KS in afternoon. A stronger cool front
will move thru Sun AM. Wrn USA high pres will build in during the
afternoon. This high will slip into the Srn Plns Mon with return
flow dvlpg here. Brzy return flow will cont into Tue with the next
strong cold front entering the Pac NW.

Temps: average cooler than normal Sat-Sun...then return to near
normal Mon-Wed. However...Tue could end up warmer than normal.

Frost/Freeze: we do need to watch Sun and Mon mornings...espcly N
and W of the Tri-Cities.

Rain: Sct shwrs and possible a tstm or two will cont Fri night.
SREF instability is fcst 500-750 J/kg. Some leftover shwrs will
linger into Sat AM...mainly E of Hwy 281. Storm total rain amts
should be 0.10-0.50" with the greatest amts E 1/2 of the CWA.
Then dry the rest of the fcst.

Fcst confidence: above average.

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Friday)
Issued at 757 PM CDT Thu Oct 3 2019

General overview:
High confidence in VFR and dry conditions through at least the
first 12-14 hours, but then high confidence in MVFR ceiling (and
perhaps occasionally MVFR visibility) through much of the latter
half of the period Friday daytime, along with passing rain
showers. Wind-wise, speeds through tonight will average under 10KT
from the east-southeast. However, speeds will pick up somewhat
from the southeast on Friday (especially by late- morning/early
afternoon), sustained around 15KT/gusts 20-25KT. Read on for more
details regarding ceiling/precipitation trends and timing...

Ceiling and precipitation timing/trends:
High confidence in VFR through at least 14-15Z, with only a
gradual increase in mainly mid level clouds through the
night/early AM. However, by sometime mid-late morning expect a
fairly rapid onset of MVFR ceiling as low clouds
develop/overspread the area from the southwest. Once these low
clouds arrive, MVFR should remain pretty common through the
remainder of the period. Precipitation-wise, at least spotty
showers/sprinkles could be in the general area as early as roughly
15Z, but any steadier rain showers should mainly occur after 18Z,
which is when prevailing -SHRA is advertised. Cannot rule out a
few isolated thunderstorms as well, but with instability quite
limited have opted to omit any formal thunderstorm mention in
TAFs at this time.

&&

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

$$

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