Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 190524

Area Forecast Discussion
National Weather Service Hastings NE
1124 PM CST Sat Feb 18 2017

.SHORT TERM...(This evening through Sunday)
Issued at 330 PM CST Sat Feb 18 2017

It`s been a very nice start to the weekend across the region, with
upper air and satellite data showing some low amplitude
shortwave ridging moving through the region, set up between
troughing along the West Coast and low pressure spinning over the
AR/LA/MS border area. Skies remain mostly clear for much of the
area, but satellite showing upper level cirrus starting to make
more of a push in from the west. At the surface, the pattern
across the area is on the weaker side, with high pressure
gradually sliding east of the area. Winds have been turning more
southeasterly with time, and speeds have mainly been in the 10-15
mph range, with an occasional gust of 15-20 MPH. No big surprises
with temperatures this afternoon, which currently are mainly in
the mid 60s.

For tonight and tomorrow, the forecast remains void of measurable
precipitation. Models are in pretty good agreement showing well
amplified southerly flow developing in the upper levels,
especially tomorrow, as the ridge axis shifts east of the area,
and that system affecting the West Coast moved further inland.
This system will become more of a precipitation player just after
the end of this period (ending at 00Z Mon). At the surface, winds
become more southerly this evening/tonight...continuing into a trough of low pressure moves onto the High Plains.
This southerly sfc/lower level flow starts advecting more moisture
northward into the area, and increased low level cloud cover and
fog becomes more of a concern tonight. Backed off the timing of
the fog a few hours, matching up with recent model data, perhaps
ending up closer to 12Z before affecting a bigger portion of the
area. Models suggesting that the south-southeastern third or so of
the CWA may see visibilities less than 1 mile, so will be putting
a mention in the HWO. As we get into tomorrow, main concern is
whether the fog dissipates as quickly (mid morning-ish) as model
say or if it sticks around longer, which could really throw a
wrench in temperatures. Confidence in highs isn`t the highest. On
the plus side, we`ll be starting the day out warmer, models are in
good agreement showing a warmer airmass sliding in from the west,
and those southerly winds should be increasing through the
morning, helping with the fog. On the minus side, while the fog
may go away, the cloud cover may be harder to shake. There is some
notable differences between models, but decided to be on the
optimistic side, keeping forecast highs near the inherited
forecast and plenty of guidance, mainly in the mid 60s once again.

.LONG TERM...(Sunday night through Saturday)
Issued at 330 PM CST Sat Feb 18 2017

Sunday night into Monday brings the CWA its next chance for
precipitation, but trends in recent model runs have not been
showing it as a big rain-maker for the area. Lift increases
across the region Sunday night ahead of the main trough axis,
which by 12Z Monday is expected to be over western portions of
NE/KS. At this point, the better chances for precip look to mainly
affect NC KS and the eastern half of our SC NE counties. Some
models suggest it amounting to little else other than drizzle,
others showing at least a few hundred j/kg of instability, so
can`t completely rule out some isolated rumbles of thunder.
Precipitation should come to an end from west-east during the day
on Monday, with gradually diminishing sky cover. Forecast highs
for Monday remain in the 60s. Also looks to be on the breezy side,
a surface front passes through, ushering in northwesterly winds
for the afternoon, with speeds of 15-20 MPH possible.

Monday night through Wednesday night, the forecast is dry. Models
are in good agreement showing upper level ridging building in
(although briefly) for Tuesday in the wake of this latest system,
before flow turns more zonal Wednesday ahead of energy moving onto
the West Coast. Looking at potential record high temperatures for
Tuesday, with models showing 850mb temps climbing into the mid
teens and a westerly-downsloping component to the winds. Current
records for Feb. 21st are 75 at Grand Island (1995) and 73 at
Hastings (1995). Current forecast highs are just short of that.
For Wednesday, temperatures a little more uncertain, as another
weak frontal boundary moves through the area, pushed by a quick
moving shortwave disturbance across the Dakotas. Forecast highs
for Wednesday are still well above normal, with mid/upper 60s
north to lower 70s south. FYI...Feb 22nd records are 76 (GI) and
75 (Hastings)...look to fall short of those.

For the Thursday/Friday time frame, a potential reminder that
winter is not quite over. Models aren`t in too bad of agreement
with the general story, showing an upper level disturbance moving
in from central/northern portions of the West Coast and into the
Central Rockies by around midday Thursday. The evolution of this
system has plenty of details to be ironed out, the 12Z GFS is more
open/progressive, clearing much of the area by 12Z
Friday...compared the ECMWF, which is a slower/closed system that
is still centered over the CWA at that same time. Both showing
temperatures being warm enough for liquid to start, with
accumulating snow as the colder air builds in. Way too early to
pin down details with totals, but it certainly is a system worth
keeping an eye on. Strong northerly winds also look to accompany
this system.


.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Sunday night)
Issued at 1114 PM CST Sat Feb 18 2017

The taf period is a little more complicated this time in
increasing souherly flow ahead of an approaching upper trough. The
low level jet increasing overnight will bring a period of low
level wind shear for KEAR. Low cloud cover will be working north
with time however latest models suggest plentiful high cloud cover
and increasing southerly winds may keep lower visibilities in fog
at bay this morning despite the increasing moisture. Stratus at
LIFR conditions look to reach the terminals in the latter taf
hours while precipitation chances look to hold off until after 06z




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