Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 161156

Area Forecast Discussion
National Weather Service Hastings NE
656 AM CDT Wed May 16 2018

Issued at 650 AM CDT Wed May 16 2018

Updated the forecast this morning for some pesky patchy fog that
developed along and north of I-80 and along the eastern CWA down
to north central Kansas. Also some showers/t-showers creeping into
the west a tad earlier than previously expected so backed up start


.SHORT TERM...(Today and tonight)
Issued at 431 AM CDT Wed May 16 2018

Weak flow aloft and rather non-descript surface features are
reminiscent of mid-summer. The MCV to the south along the
Kansas/Oklahoma border will continue moving east southeast, so
this does not look like a player for our CWA.Instability and shear
will be weak. Convection to the west touched off by mid-level
perturbation struggles to move east. More convection could re-fire
during the day from insolation, and affect roughly the western
half of the CWA, but will quickly diminish in the evening. I like
ConsShort highs today in the lower 80s for the entire CWA and lows
in the mid to upper 50s look prudent for tonight.

.LONG TERM...(Thursday through Tuesday)
Issued at 452 AM CDT Wed May 16 2018

An active pattern will return to the forecast area with multiple
rounds of convection possible Thu night through Sat, some of which
could contain strong to severe t-storms.

The upper level pattern will generally remain a bit more reminiscent
of an early-mid summer pattern vs. a mid-late spring pattern, with
ridging being most dominant from Pac NW into S Canada/N U.S. As a
result, any trofs are forced underneath this ridge and generally
come out into the Plains weaker/slower than we typically see for
this time of year. One such trof will begin to organize across the
western CONUS and gradually weaken and shunt the ridge over the N
Rockies off the the E/SE. This trof will then eject E/NE as several
weak to moderate waves late this week instead of one stronger lump
of energy. As a result, multiple rounds of showers and thunderstorms
are expected from late Thu night through Fri and possibly much of
Sat as well.

Thursday: The NAM is trying to develop some elevated convection
across the N early in the morning along a subtle H7 theta-e
gradient. Will have to watch this for some "sunrise surprise"
convection, but GFS, EC, SREF and hi-res ARW & NMM all remain dry so
continued the dry forecast. Otherwise, the daytime hours should
remain dry and warm in the mid 80s with a steady S breeze.
Convection will likely develop across the western High Plains Thu
aftn then gradually shift E overnight. Models are in pretty good
agreement that timing of this convection should hold off until after
midnight. A 30-40kt LLJ will attempt to sustain the storms
overnight, but overall feel activity will be on a weakening trend as
it arrives from the W. Nonetheless, model progs of MUCAPE 1500-2500
j/kg and 0-6km bulk shear values of 25-35kts suggests at least some
potential for a few strong to marginally severe cells with quarter
size hail and gusty winds late Thu night.

Friday: Could see some leftover shower and t-storm activity continue
thru mid-morning for parts of the area, but overall, should see a
lull in activity from midday thru at least mid aftn. The strongest
lobe of energy from the W trof is forecast to eject onto the Plains
Fri aftn into overnight. Current timing and placement of sfc/upper
features suggests initiation should be just W/SW of the area Fri
aftn, with increasing t-storm chances locally Fri eve-overnight.
This activity may be severe given steep mid level lapse rates in
place along with MUCAPE 2000-3000 j/kg and 30kts of deep layer
shear. I anticipate activity to be growing upscale/consolidating as
it arrives into CWA with main threats of large hail and damaging

Weekend: The aforementioned main lobe of energy will slowly wallow
its way across the area on Sat, likely leading to additional off and
on shwrs and t-storms. Will have to watch the S & E CWA for strong-
severe storms in the aftn, but this will largely depend on trends in
rain/cloud debris. The rest of the CWA will likely be cooler & more
stable. As far as rain amounts go, could see some areas come out of
this with fairly significant rainfall. WPC QPF forecast is currently
highlighting south central NE with 1-2.5" of rain from Thu night
thru Sat night. Obviously locally higher and lower amounts should be
expected. We`re not overly saturated soil wise but will have to
monitor hydro situation if activity sets up just right. Sunday
should be mainly dry and cooler.

Models bring warmer temperatures and a return to off and
on (relatively unorganized) rain chances for early next week.


.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Thursday)
Issued at 650 AM CDT Wed May 16 2018

Some patchy MVFR this morning, and perhaps some isolated thunder
today. VFR conditions after MVFR visibility clears.




SHORT TERM...Heinlein
AVIATION...Heinlein is the U.S. government's official web portal to all federal, state and local government web resources and services.