000
FXUS63 KGID 181133
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
633 AM CDT Tue Jul 18 2017

.SHORT TERM...(Today and tonight)
Issued at 411 AM CDT Tue Jul 18 2017

The compact upper low that was responsible for the ongoing
thunderstorms will continue to weaken and move eastward this
morning, allowing thunderstorms to gradually exit the area by
around 15Z. Localized heavy rain remains the main threat with the
remaining storms as the SPC Mesoanalysis page shows PW values
around 1.8". Luckily, storms are starting to move away from areas
that have seen 3-4"+ of rain overnight. Therefore I think any
additional hydro issues will be avoided.

This afternoon, high temperatures will range from the low 90s to
around 100 degrees. the latest guidance is actually a couple
degrees cooler than previous forecast, which does create some
uncertainty on whether we actually will reach heat advisory
criteria today. That said, evaporation from last night`s rain may
push dewpoints a few degrees higher, which would still result in
heat index values in the low 100s. Either way, it is going to be
hot and muggy and we have several more days of heat coming up this
week, so we will maintain the heat advisory as-is.

Late this afternoon, models show essentially uncapped instability
across central and north-central Nebraska, but models are pretty
reserved with QPF for now. Therefore I think that thunderstorms
will be pretty isolated until 850mb convergence increases later in
the evening and overnight and organizes storms into a few
southeastward- moving multicell clusters. With around 2000J of
MUCAPE, and 20-30 kts of bulk shear, there is some severe threat,
albeit marginal. I expect updrafts to be short-lived in nature and
will likely pulse up and down quickly, but isolated severe hail
and downburst winds are possible through the evening and
overnight.

.LONG TERM...(Wednesday through Monday)
Issued at 411 AM CDT Tue Jul 18 2017

Subtropical ridge will be in full force for Wednesday and Thursday,
with an excessive heat watch in place for this period as the heat
index will top 100. Then, the ridge weakens and retreats somewhat
toward the weekend and highs lower to the mid to upper 80s by
Sunday, but also allowing more shortwave trough activity in, and
allowing some thunderstorm activity from time to time, with surface
boundary potentially hanging around for part of the time as well
that may serve as a focus for convection.

&&

.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Wednesday)
Issued at 628 AM CDT Tue Jul 18 2017

Thunderstorms have moved east of EAR and are currently in the
process of exiting the GRI vicnity.

Winds become southerly this afternoon, around 10 kts.

Scattered thunderstorms are expected to develop north of the
terminals late this afternoon, potentially moving into the
area between 0Z and 4Z. I don`t expect these storms to be nearly
as long-lasting as the storms were last night, though.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening
     for NEZ039>041-046>049-060>064-072>077-082>087.

     Excessive Heat Watch from Wednesday afternoon through Friday
     evening for NEZ039>041-046>049-060>064-072>077-082>087.

KS...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening
     for KSZ005>007-017>019.

     Excessive Heat Watch from Wednesday afternoon through Friday
     evening for KSZ005>007-017>019.

&&

$$

SHORT TERM...Mangels
LONG TERM...Heinlein
AVIATION...Mangels