Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 09/14/19

Area Forecast Discussion

National Weather Service Hastings NE

 1009 PM CDT Fri Sep 13 2019

.UPDATE...
Issued at 1009 PM CDT Fri Sep 13 2019

Have expanded slgt chc POPs to include areas E of Hwy 281 in south
central NE to account for some trends on the RAP/HRRR. Still not
overly impressed with the chcs given upper jet structure and lack
of strong convergence, but enough WAA/moisture advection to
justify the hi-res output.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 153 PM CDT Fri Sep 13 2019

Aloft: The Westerlies were moderately-amplified along the US-Can
border per aircraft obs/WV imagery/RAP tropopause analyses. The
low that delivered the fresh cool Canadian air mass was over Wrn
Ontario. A weak shrtwv trof was over the Nrn Rckys. The flow will
be from the W over NEB/KS tonight...but that trof will cont moving
E. It will cross the CWA Sat AM and shift winds to WNW.

Surface: 1024 mb high pres was over KS and drifting E. Weak low
pres was over Srn AB. A warm front has formed and extends SE into
SD with a cool front extending SW thru the Nrn Rckys. The low will
weaken while the fronts move E. The cool front will also
frontolyze with the remnant sfc trof approaching the CWA by sunset
Sat eve. The CWA will remain in the warm sector thru tomorrow.

This afternoon: Very nice. Gotta love the comfortable/low-
humidity air. Altocu CIGs 11-12K ft have been over SW NEB and NW
KS thru the day. Some of this will be drifting E into the CWA...
but the trend has been for dissipation.

Tonight: Unfortunately...a 25-35 kt low-lvl jet will dvlp and
higher dwpts/humidity will circulate back into the rgn.
Obs/satellite have shown pockets of low stratus over W TX today.
With the departure of the high...this low-lvl mstr will advect NE
into the CWA tonight. There will be some patchy low stratus around
late tonight. Mdls are currently indicating that it will not be
widespread.

Low-lvl mstr return will result in dvlpmt of conditional
instability. Modest convergence/ascent could result in a few
isolated high-based shwrs and weak tstms over N-cntrl KS.

So bottom line is becoming partly cldy tonight.

Sat: Overall should average partly cldy...espcly E of Hwy 183.
Lots of uncertainty on coverage of low stratus...but ample low-lvl
mstr will result in SCT CU from late morning on. There still
could be a few isolated high-based shwrs and wk tstms over N-cntrl
KS.

Forcing/convergence will be wk along the sfc trof...but can`t
completely rule out an isolated tstm or two dvlpg...probably S and
E of the Tri-Cities. CIN erodes to the point that something could
pop thru the wk cap. With temps 85+ and dwpts in the mid-upr
60s... MLCAPE could be as high as 3000 J/kg per the 09Z/SREF. 0-6
km shear is fcst 25-35 kt. That combination will be more than
sufficient for any storms that dvlp to become svr...if tstm
initiation occurs.

Temps about 5-6F warmer than today.

Breezy espcly in the morning as the boundary layer mixes into
what`s left of the diminishing low-lvl jet.

.LONG TERM...(Saturday night through Friday)
Issued at 153 PM CDT Fri Sep 13 2019

Because of the longwave pattern...summer just won`t give up.
Temps next week will be more like summer than meteorological fall
...with daytime highs and lows about 10F above normal.

Aloft: A low currently over the GlfAK is fcst to dive down the W
coast of N America Sat-Sun.. This low will carve out a new
longwave trof over the Wrn USA as it presses inland Mon-Tue. These
initial height falls over the W Sun will force a ridge to build
over the Plns which will drift into the Ern USA Mon-Tue with SW
flow over NEB/KS. The last 2 runs of global mdls (GFS-FV3/CMC/
EC/UKMET) are in good agreement that a shrtwv trof will come out
of the W and into the Dakota`s Tue night into Wed. Spread
increases significantly thereafter as the mdls struggle with if
and how the Wrn trof reloads...as there could be another low
dropping down the W coast. The configuration of the flow over the
Wrn/Cntrl USA is highly uncertain.

Surface: The CWA will remain in the warm sector Sun-Tue night.
Low pres over the Nrn Rckys will head into the Canadian Prairies
Wed. The associated weakening cool front will cross the CWA and
then dissipate. Thereafter there is just too much uncertainty to
say much.

Temps: Way warmer than what they should be for mid Sep Sun-Tue.
Temps should drop back closer to normal Wed...but still favoring
slightly warmer than normal. Temps could then go right back up
Thu-Fri...which is not currently reflected in the fcst...but
possible as the rgn is likely to be in the warm sector of new low
pres over the Wrn USA.

Rain: The slight chance for an isolated tstm Sat afternoon will
linger into Sat eve. Otherwise...dry Sun-Tue. Wed-Fri the fcst
does have a slight (20%) chance for isolated tstms...but this is
probably overdone. These periods will be mostly dry for most
locations.

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 658 PM CDT Fri Sep 13 2019

Significant wx: Low level wind shear (LLWS) and potentially IFR
stratus.

Tonight: Quiet this eve with clr skies and SW to SSW winds around
10kt. After 06Z an incr low level jet up to 40-45kt will cause
some low-end LLWS at both terminals. Also, incr low level
moisture may lead to development/advection of stratus with CIGs
around 500ft by around 10-11Z. Models are still uncertain as to
the coverage/persistence of the stratus specifically at the
terminals, but feel there is decent chc for at least SCT coverage,
thus have maintained the SCT005 group from the previous TAF
package. Could envision a few hr window of BKN stratus leading to
IFR flight cat, but not enough confidence to go prevailing at
this time. With the incr in low level jet there may also be some
sfc gusts around 20kt late overnight. Any isolated elevated
convection should remain to the S. Confidence: LLWS/wind-high,
CIGs-medium.

Saturday: SCT to perhaps BKN stratus around 500ft should continue
thru about 14Z then gradually rise and morph into statocu around
midday. FEW to SCT CU are expected for the aftn with bases rising
to 2000-2500ft. Wind shear will end by around 14Z, but breezy
SSW/SW sfc winds will continue with gusts 19-23kt expected.
Confidence: Medium to high.


&&

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

$$

UPDATE...Thies
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Thies