Area Forecast Discussion
Issued by NWS Hastings, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGID 201704
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
1204 PM CDT FRI MAY 20 2016

.SHORT TERM...(Today and tonight)
Issued at 406 AM CDT Fri May 20 2016

The main concerns will be stratus this morning and some light shower
activity possible in the east today, along with some thunderstorm
chances in our southwest late tonight.

We could be socked in for a good chunk of the day with stratus as
low-level sky cover has filled in for most of the area. Showers now
look possible in the eastern CWA due to insolation occurring near an
axis of some mid-level frontogenetic forcing. This forcing should
move off to the east by late afternoon and any showers left should
die with the sunset to the east. This is not universally recognized
among short term hi res models, but the HRRR has been consistently
pointing toward this. The NAM indicates this potential slightly
farther east, just outside of the CWA. This is enough to include our
far east for POPs, but I left out thunder as we lack sufficient
instability.

Still looks like we could get the remnants of an MCS in our
southwestern CWA late tonight. Thunderstorms will erupt along the
surface trough/warm front in the lee of the Rocky Mountains. These
thunderstorms should move east this afternoon/evening, enhanced by a
developing low-level jet. Most models indicate that the theta-e axis
should stay mainly west of the CWA, and may just make it into our
southwest. Enough for me to keep slight chances of thunderstorms in
our southwest. Continued the mention of some patchy fog late tonight
as there is some indication of this with the SREF, but this signal
is trending weaker compared to 24 hours ago.

I generally like superblend temperatures for highs and lows and went
with mid to upper 60s for highs and mid 50s for lows tonight. Dew
points should steadily increase into the 50s tonight with increased
moisture flux, adding to the addition of patchy fog for late
tonight. There is an outside chance that we could get some
stronger wind gusts in our southwest, but the chances are so slim
that I will likely not include this in the HWO.

.LONG TERM...(Saturday through Thursday)
Issued at 406 AM CDT Fri May 20 2016

Aloft: A ridge will be over the plains Sat with a large trof and low
over the Wrn USA. The ridge will depart to the E Sun with SW flow
thru Wed. Substantial spread then develops over the E Pac which
determines when the Wrn trof will eject onto the Plains. Even the
00Z/19 and 12Z/19 EC runs differ by 700 mi with the low between
AK/HI next Fri. The 00Z run did come in similar to the 12Z/19 run.
The 12Z/19 EC ensemble mean suggests the trof moves thru sometime
Thu or Fri with a ridge building the weekend of the 28th-29th.

Surface: High pres will be over the MS valley at daybreak Sat with a
Pac cool front advancing thru the Wrn USA. These features will
slowly creep E thru Sun. The cool front will weaken as it emerges
from the Rockies...with a dryline/lee trof crossing the fcst area
Sun night. This remnant boundary will become parallel to the SW flow
aloft and provide the focus for periodic tstm chances thru next
week. Tstm cold pools will shift the location of this wavy boundary
over time.

Some Daily Details...

Sat: there`s no synoptic forcing...but persistent WAA/moisture flux
associated with the low-lvl jet underneath the bourgeoning EML could
result in a couple morning tstms. Diurnal heating within the lee
trof should result in a few more tstms developing late afternoon
mainly W of the fcst area. Cannot completely rule out a tstm at any
time...but most of the day will be dry for most locations.

Temps are below average confidence due to uncertainty in cloud
cover.

Sun: similar to Sat in regard to precip. Can`t entirely rule out a
tstm or two...but the models agree on a shortwave trof ejecting NE
from CO/WY into SD Sun night along with the remnants of the cool
front emerging from the Rockies. This will provide synoptic forcing
for tstms. The ingredients will already be in place with rich sfc
dwpts in the low-mid 60s underneath an EML.

Windy in the warm sector. SSE winds will G25-40 mph.

Expect tstms to initiate late Sun afternoon from SD into Wrn Neb.
They should expand during the evening and cross the fcst area during
the night. Shear and instability should be sufficient for some
storms to be svr. Time of day will limit svr potential some. Given
unidirectional wind profile parallel to the approaching dry trof...
expect a linear convective mode.

Mon-Thu: Uncertainty is very high given the broad SW flow. Tstm
chances will be dictated by low-amplitude shortwave trofs that have
low predictability this far out...as well as the nocturnal low-lvl
jet impinging on the various boundaries.

&&

.AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Saturday afternoon)
Issued at 1155 AM CDT Fri May 20 2016

THE PRIMARY CONCERN WILL CENTER AROUND THE LOW CLOUDS...WHICH ARE
EXPECTED TO PERSIST THROUGHOUT THE TAF VALID PERIOD. WE WILL
GRADUALLY SEE THE CLOUDS LIFT SOME THIS AFTERNOON INTO LOW END
VFR...BUT EXPECT CLOUD BASES WILL ONCE AGAIN QUICKLY LOWER AFTER
DARK BACK INTO MVFR AND EVENTUALLY IFR. WILL ALSO INCLUDE THE
POSSIBILITY OF LIFR CEILINGS FOR THE FEW HOURS AROUND DAWN
SATURDAY MORNING. OVERALL EXPECT DRY WEATHER AND SOUTH SOUTHEAST
WINDS WILL PERSIST.

&&

.GID Watches/Warnings/Advisories...
NE...None.
KS...None.
&&

$$

SHORT TERM...Heinlein
LONG TERM...Halblaub
AVIATION...Wesely


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.