Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 09/19/19
Area Forecast Discussion
National Weather Service Hastings NE
724 PM CDT Wed Sep 18 2019
.SHORT TERM...(This evening through Thursday)
Issued at 306 PM CDT Wed Sep 18 2019
Aloft: RAP tropopause analyses and aircraft wind data depict weak
SW flow over the Plns with a longwave ridge from the Wrn Gulf to
Hudson Bay. A deep/digging trof was along the E coast. Wk SW flow
will remain over NEB/KS thru tomorrow as the Wrn trof moves
inland. By 00Z/Fri it will extend from ID-NV.
Surface: 997 mb low pres was along the MB-ONT border with a wk
cool front extending SW acrs Ern NEB to SW KS. This front bisects
the CWA and has become stationary from near Phillipsburg KS-Clay
Ctr-McCool Junction. Small wk high pres was over the Black Hills.
This front will remain stationary thru tonight. An MCS is fcst to
dvlp over Ern NEB or IA and it could send an outflow boundary
into the CWA. The front is fcst to lift N out of the area into Nrn
NEB tomorrow...putting the CWA back into the warm sector...but
the potential outflow boundary could be a complicating factor.
Rest of this afternoon: variable between mostly sunny and partly
cldy. There is a drastic diff in dwpts across the front and mdls
are not handling this well at all. Used RAP mdl but had to
manually shift everything SE to better match the location of the
front. This will need to be something to monitor in short-term
fcst updates thru this eve.
Can`t rule out an isold tstm dvlpg along and SE of the front...
where CIN is weakest...but there no help aloft.
Tonight: Mostly clr to partly cldy. Can`t rule out an isold shwr
or tstm. An MCS is fcst to dvlp from Ern NEB into IA. This could
send an outflow boundary into the CWA late. If the mdls are right
...it probably won`t trigger any shwrs/tstms. But the NAM nest and
NMM do dvlp tstms btwn JYR-HJH. Even if that does not occur...am
concerned the outflow boundary could also result in formation of
low stratus...espcly an aviation concern.
Thu: Mostly clr to partly cldy. Can`t rule out some tstms E of Hwy
281 in the morning. The areas that cooled down today will warm
right back up with mid 80s-low 90s from the Tri-Cities S and W.
.LONG TERM...(Thursday night through Wednesday)
Issued at 306 PM CDT Wed Sep 18 2019
Aloft: The last 3 runs of the GFS-FV3/EC/CMC/UKMET all maintain
SW flow over the Plns thru Sat. The deep Wrn trof will deamplify
and lift into the Nrn Plns Sat. The tail end of this trof is fcst
to cross NEB/KS Sun. A shrtwv ridge will arrive Mon. Upstream...
another moderately trof is fcst to move into the Wrn USA. The mdls
suggest a cut-off low will form over the Desert SW Mon-Wed...with
low-amplitude cyclonic WNW flow dvlpg acrs the Nrn USA.
Surface: The next cool front that will move thru NEB/KS was
already over the Wrn USA. The CWA will remain in the warm sector
Fri with this front moving thru Fri night or Sat AM. High pres
will briefly build in Sat. The 00Z EC ens mean suggests we need to
watch for a sfc low to form along the front over KS Sat night.
This would encourage MCS dvlpmt. The next low fcst to move into
Wrn Canada will induce warm frontogenesis from MT-NEB Sun. The
associated cool front is fcst to weaken and cross NEB/KS as a trof
Tue. A stronger cool front is slated to move thru Wed.
Temps: Thankfully...the recent summer heat that belongs in July
and not Sep will finally be gone. This fcstr hopes that`s it for
this year. Temps will still average just a fuzz above normal...but
we will see more 70s and low 80s for highs...and lows in the 50s.
Looking beyond Wed 9/25...ensembles from multiple natl centers
suggest the MJO will head into phases 8 and 1. Those phases
typically result in cooler than average temps. That should mean we
will enjoy some nice fall wx instead of summer in Sep.
Rain: While the fcst has a chance of tstms every day...am not
impressed with overall chances for rain. While the chances of rain
are not zero...believe the fcst is overdone with the mention of
shwrs/tstms. The pattern just doesn`t look that favorable.
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 610 PM CDT Wed Sep 18 2019
FCST challenge for tonight is whether some MVFR/IFR stratus moves
in tomorrow morning. A few of the models hinting at it. GRI is
more likely of the two sites to see stratus move in tomorrow
morning. Continued with the FEW006 as a hedge for now. If any
ceilings do move in, they should scatter out by mid-morning.