Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 221053

Area Forecast Discussion
National Weather Service Hastings NE
553 AM CDT FRI JUL 22 2016

.SHORT TERM...(Today and tonight)
Issued at 329 AM CDT Fri Jul 22 2016

Hot summer temperatures will persist today under the influence of an
upper level ridge of high pressure extending from the Southern
Plains, north into the Central Plains. The ridge axis will
gradually deamplify/shift south as a series of shortwave troughs
translate across the Central and Northern Plains. H85
temperatures remain toasty in the upper 20s celsius to near 30
celsius and resultant high temperatures this afternoon will top
out well in the 90s to over the century mark. The combination of
the hot temperatures combined with dewpoints in the upper 60s and
70s will result in heat indices in the 100 to 110 degree range and
our current headline for excessive heat will be maintained.

Thunderstorm chances are not looking overly impressive, but are not
zero either. During the predawn hours convection has been fairly
isolated across western Kansas, and is not looking overly
promising to reaching our area attm. Dry weather is expected for
the majority of the day as it will be hard to overcome the warm
temperatures aloft. Heading into tonight, convection is expected
to develop along the high plains and migrate eastward during the
overnight hours, aided by a strengthening low level jet.
Confidence is not high on how widespread this activity and have
only carried isolated to scattered pcpn chances after dark.

.LONG TERM...(Saturday through Thursday)
Issued at 329 AM CDT Fri Jul 22 2016

Primary forecast concerns through the long term lie with continued
hot temperatures early on and thunderstorms through mid-week.

Starting off the period Saturday morning, models in decent agreement
showing generally zonal flow in place in the upper levels across the
region. The CWA sits between elongated high pressure across the
southern CONUS, while a low pressure system is working its way east
near the MT/Can border. An embedded weak wave and lingering forcing
from a LLJ may result in some lingering precipitation into the
morning hours, but expect it to be waning/scattered in nature, so
kept chances at 20%. At the surface, south-southwesterly winds are
expected to be in place to start the day, with low pressure
extending from near the CO/KS border northward into the Dakotas.
Looking to the rest of the day and into the evening/overnight hours,
the surface cold front will continue to sag south as that upper
level low slides east along the US/Can border. Not a ton of
differences between models with the timing/location of the SW-NE
orientated front, showing it pushing into western portions of the
CWA early-mid afternoon, into central portions around mid evening
and into far southeastern areas by sunrise Sunday. This front will
help provide a focus for thunderstorm chances, but confidence in the
overall coverage is pretty low. The brunt of the upper level forcing
will be well north of the CWA, though there will be some help with a
30-ish kt LLJ developing in the evening. Models continue to show
plenty of warm temps aloft/capping, thinking is that activity will
be scattered, so kept PoPs in the 20-30% range. Should thunderstorms
develop, deeper layer shear isn`t the greatest, but there is
instability to work with, so potential is there for strong/severe
thunderstorms. Good chunk of the CWA is included in the SPC Day 2
Marginal Risk.

Outside of the preciptiation chances for Saturday, another concern
lies with the continued hot temperatures. Main change to the
forecast was to extend the Excessive Heat Warning into Saturday.
With the surface frontal boundary really not making much of a push
into the CWA until later in the day, that hot air mass remains in
place. Forecast high temperatures range from the mid 90s north to
just over 100 in the south. Some uncertainty with dewpoints, some
models try to mix them out a bit more with the more southwesterly
component to the winds. Even with that though at least blended into
the inherited dewpoints, still ending up with peak heat index values
in the 100-106 range.

As we get into Sunday, there looks to be some temperature "relief".
A few differences between models with exactly how far south the
surface front ends up, most support a location roughly along I-70 in
northern KS. This leaves the CWA (at least a good portion of it)
with more easterly winds through the day. Confidence in
precipitation chances, or lack of, is low. Models continue to show
the potential for lingering activity in the morning, with another
weak wave working its way in late, so kept PoPs in through the day.
Portions of the CWA near that sfc boundary were also included in the
SPC Day 3 Marginal Risk. Afternoon high temperatures currently
forecast to reach the upper 80s to mid 90s.

Monday through Thursday, confidence in the preciptiation chances is
low. Upper level flow across the region remains generally zonal,
leaving the CWA under the threat of period shortwave disturbances
moving through. Hard to go with more than 20-30% PoPs, though models
suggest the potential for a stronger complex midweek. Lot of details
yet to be ironed out between models. High temperatures through this
time frame mainly in the mid 80s to mid 90s range.


.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Saturday morning)
Issued at 551 AM CDT Fri Jul 22 2016

VFR conditions are forecast through the taf period. Clouds are
forecast at mid and high levels, with an increase in cloud cover
overnight as convection along the high plains moves eastward.
There is an outside chance for a shower or thunderstorm, however
confidence in timing and occurrence at the terminals remain low
and have not included attm.


.GID Watches/Warnings/Advisories...
NE...Excessive Heat Warning until 7 PM CDT Saturday for NEZ039>041-

KS...Excessive Heat Warning until 7 PM CDT Saturday for KSZ005>007-



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