Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 230525
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
1225 AM CDT Tue May 23 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 245 PM CDT Mon May 22 2017

The biggest issue for this forecast will be the weather in the first
period, right off the bat.

This evening we have a cold front slicing through the CWA. Convection
already fired along the front in South Dakota, so I have taken out
the delineation of our southeast being where the most likely storms,
and hence, marginal severe chances will be. I stress the word,
marginal, because we seem to top out with a CAPE of 1000 J/kg this
afternoon, and perhaps a bulk shear in the 0-6 km layer in the 30-40
KT range. This would indicate a marginal severe risk for this time
of year. Also, it is looking less likely that any tornadic activity
will develop as the wind profile is looking more unidirectional.
There is what looks like a stationary outflow boundary bisecting
the CWA, which gives me at least some pause regarding possible
quick landspout type spinup weak tornadoes, but chances do not
appear all that high. Just something to keep an eye on just in
case. Some short term models are indicating that we could have
some elevated convection linger well behind the cold front this
evening, so I was not in too much of a hurry in removing chances
of precipitation. After sunset, the chance of any storms/severe
weather quickly diminishes. We will need to wait for the mid-upper
level trough axis to pass through tonight for the rain chance to
completely shut off, probably a little either side of midnight,
depending on where in the CWA it is.

Although the shortwave trough passes through near midnight tonight,
the closed low it was attached to will waddle south, closer to the
CWA, which will put us closer to its influence on its southwest
side, putting us into an area that will probably see some afternoon
showers pop up, with at least isolated coverage. Tuesday will
probably be the most miserable out of the entire forecast. We will
struggle to see 60 degrees and there will be plenty of sky cover
developing, along with the shower activity, and a northwest wind
blowing at a stout clip with northwest wind gusts easily making 30
mph. Shower activity and sky cover will be mostly diurnally driven,
and toward sunset, we should begin having a decrease in both, as
well as wind speeds.

.LONG TERM...(Tuesday night through Monday)
Issued at 245 PM CDT Mon May 22 2017

By Wednesday, the closed low will have moved far enough south and
east to finally put us in an area of subsidence as mid-level
shortwave ridging occurs and 850 mb temperatures should allow highs
to bump up a bit more into the mid 60s to near 70, but still
dragging a bit below average for this time of year. Some more
convection possible with cold front Thursday. We will be in a bit
of an active pattern heading into the weekend. Models differ in
which day will be rainier, as the GFS is now giving us more rain
on Sunday as opposed to Saturday from the ECMWF. We have roughly
the same 20/30 POPs for the afternoons of Saturday/Sunday,
although we do have some higher POPs Saturday morning leftover
from convection possible Friday night. Also, we have nudged up
highs for Monday a bit as latest long term models are trending
warmer.

&&

.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Tuesday)
Issued at 1218 AM CDT Tue May 23 2017

Showers have pushed south of the terminals and skies will
gradually clear overnight tonight. Breezy northwest winds are
expected tomorrow, likely gusting around 25 kts for most of the
daytime. Scattered showers are also expected to develop during the
afternoon, but ceilings are currently expected to stay in the VFR
range.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&

$$

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



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