Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 140934

Area Forecast Discussion
National Weather Service Hastings NE
434 AM CDT Wed Mar 14 2018

.SHORT TERM...(Today and tonight)
Issued at 434 AM CDT Wed Mar 14 2018

For the majority of our coverage area (CWA), especially Nebraska
zones, today marks the much-awaited warmest/nicest day of the
week, as temps jump a solid 15-20 degrees above those of
yesterday. Not surprisingly given this warm-up, winds will become
somewhat breezy as well (especially southeast), but not overly-
strong either. Unfortunately for fire weather concerns, the
combination of breezy winds and low relative humidity pushes a few
of our far southern/southeast counties into "critical" territory,
prompting Red Flag Warning issuance (please refer to the separate
FIRE WEATHER section below for more details). Otherwise, these
next 24 hours remain guaranteed dry, with another day of plentiful

Taking a look at the current/recent weather scene as of 330 AM:
It`s been another uneventful night. In the mid-upper levels (but
especially from 500 millibars up), water vapor satellite imagery
and short term model data confirm continued north-northwesterly
flow, as the Central Plains resides on the downstream side of a
high-amplified ridge axis centered just west of the Rockies.
Meanwhile, large-scale troughs flank this ridge, one dominating
the eastern CONUS and another pushing increasingly into the far
western CONUS. With very dry air aloft, skies are again
essentially crystal clear. At the surface, the ridge that was
centered well to our north 24 hours ago has steadily shifted
south, currently centered in the OK/KS/AR/MO border region. In
response to this, surface breezes have generally become
southwesterly in most areas as the night has gone on, but with
speeds largely under 12 MPH. Due to localized variations in low-
level mixing, several automated stations have reporting downright-
calm winds at times. This has resulted in somewhat erratic/tricky
trends with hourly temperatures, with some areas rising slightly
since earlier in the night while other places remain steady to
slowly-falling. When all is said and done, however, actual
overnight low temps in most of the CWA will probably register in
the 23-28 range, which is 5+ degrees warmer than yesterday.

Now looking ahead forecast-wise through today/tonight...

Other than the fire weather concerns (again, see below), most
folks should find this a very nice mid-March day as long as they
don`t mind a little breeze. In the mid-upper levels, the western
CONUS ridge axis will slide a bit farther east, getting closer to
the Central Plains over the course of the day. Other than perhaps
some very limited wisps of mid-high clouds, this should be another
very sunny day. At the surface, a modest pressure gradient will
set up between the southeastward-departing ridge axis and low
pressure just starting to organize off the Front Range. The net
result for our CWA will be steady-but-not-overly-strong south-
southwest winds, with speeds peaking as usual between late morning
and late afternoon. For most of the CWA, expect sustained speeds
10-15 MPH/gusting to around 20 MPH. However, for roughly our
southeastern one-fourth, sustained speeds closer to 20 MPH/gusts
25 to perhaps near 30 MPH are more likely. Temperature-wise, made
very little/hardly any change to previous forecast. Although far
from record highs, have most places aimed 67-70, with far
southwest counties such as Rooks/Osborne most favored to perhaps
touch 72-73.

This evening/tonight:
Another quiet and dry night, but the very first hints marking our
upcoming/more active weather pattern will get underway. In the
mid-upper levels, the center/axis of the aforementioned ridge axis
will finally move overhead, while the leading edges of the western
trough edges farther east across the Rockies. Skies will average
mostly clear, but there will be a modest increase in mainly high
level cirrus as the night wears on. At the surface, the evening
starts out with fairly light/decreased southerly breezes all
areas. However, as the night wears on, a weak cold front will sag
southward across much of the CWA, reaching roughly the NE/KS
border by sunrise Thursday. As this front slowly moves south,
breezes will gradually turn more easterly in its wake, but with
speeds mainly only around 10 MPH or less. Our far southern zones
in KS, who will be last to see this cold frontal influence, will
actually hold onto southerly breezes the entire night, and
although not as strong as during the day some gusts to around 20
MPH are most favored here. Temp-wise, also made very little change
to previous lows, with most of the CWA aimed into the low-mid 30s,
but ranging from as cold as the upper 20s in far northern counties
such as Valley/Greeley, to near 40 in our extreme south in KS.
Overall though, lows roughly 5-10 degrees milder than this current

.LONG TERM...(Thursday daytime through Tuesday)
Issued at 434 AM CDT Wed Mar 14 2018

Dry conditions remain in the forecast at the start of the long term
period Thursday, but high temperatures remain tricky. Aloft,
models remain in good agreement showing a well amplified pattern
across the CONUS at 12Z Thursday. The main ridge axis extends
north through the Plains, sitting between areas of low pressure
just off both the NW and NE coasts. At the surface, a frontal
boundary looks to set up near the NE/KS border, as high pressure
continues settling south out of Canada, and more importantly, low
pressure is becoming better organized over eastern CO. Through the
daytime hours, though the forecast is dry, attention turns to the
west, where a shortwave disturbance associated with the main west
coast slides through the 4 corners region and into CO. As a
result, the sfc low over eastern CO continues to deepen, and wind
speeds should increase. Not much has changed with much of the CWA
(state line and north) expected to have east winds through the
day, there is more of a question with our KS counties, as where
that front ends up will determine how much/if any southerly
component there is to their winds. Sustained speeds around 20 mph
are certainly possible. This frontal boundary makes the
temperature forecast difficult, and still have a 20-ish degree
gradient from north-south, with mid 50s in the north to mid 70s
south. It`s those areas in the middle that have the least
confidence, as any shift in the placement of the front would mess
with temps. It`s not out of the question that portions of our KS
counties could see near critical fire wx conditions, but currently
don`t have RH values dropping below the lower 20% range.

Still looking at Thursday night through Friday night as the return
of preciptiation chances, with some question lingering with the more
exact details. Thursday evening, precipitation is expected to
develop along/north of the main sfc front as larger scale lift
increased with the approaching upper level disturbance along with an
increasing southerly LLJ nosing into the area. Models still showing
the potential for at least a few hundred j/kg of CAPE, so a few
thunderstorms will be a possibility for a good chunk of the CWA. As
we get further into the overnight hours/Friday morning, models still
showing this upper level disturbance becoming more organized into a
closed low, but differ with its exact placement, ranging from SW
Neb, to our NC KS counties, to NW KS. Those differences continue on
through the daytime hours on Friday, and at 00Z Sat placement of the
low is anywhere from northeast NE to SE NE to NW MO. These
differences are resulting in lower confidence in how quickly any
colder air moves in from the northwest, and thus precipitation type.
The GFS is notably warmer at the sfc, but even the ECMWF remains
above freezing through Friday morning...the NAM is on the colder
side. There is still some concern of a wintry mix early Friday
morning, but the colder solutions would have to pan out. At this
point confidence in that occurring isn`t high, and have any wintry
mix confined to far northern portions of the CWA. Uncertainty in
ptype continues through the day on Friday, esp across NNWrn portions
of the CWA, but currently have liquid as the main type. Potential
for more snow/wintry mix building in Friday evening/night still is
in the forecast, but the event will be winding down so amounts would
be light.

Shortwave ridging aloft in between systems looks to keep the start
of the weekend dry, before PoPs return again Sun/Mon. Increasing
larger scale lift ahead of the main system will spread preciptiation
chances northward across the region on Sunday, before the main
system swings through Sun night and into Monday. Plenty of details
to iron out here, so confidence is on the lower side. Forecast dries
out again for Tuesday.

As far as temperatures go Fri-Tues, overall not looking at any
significant swings either way. Confidence in highs on Friday isn`t
high due to the precipitation potential, and while highs currently
range from near 40 in the far north to near 60 in the far south,
could see temps trend down more, esp in the north. Have 40s/50s for
Sat, Mon and Tues..perhaps a few degrees warmer for Sun.


.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Thursday)
Issued at 124 AM CDT Wed Mar 14 2018

Confidence remains VERY high in VFR ceiling/visibility, with
essentially no cloud cover whatsoever. That leaves winds as the
main concern, and although not as downright-light as the past 24
hours, they should still not be a big issue. The majority of the
time, sustained speeds should average at-or-below 11kt, with the
overall-strongest focused during the daylight hours between
15-22Z. Direction will prevail between southerly and southwesterly
most of the time, but late Wednesday evening will start to turn
more easterly. Lastly, there are hints of some "marginally-
mentionable" low level wind shear (LLWS) mainly between 09-15Z
this morning, but with this shear magnitude mainly less than 30kt,
will refrain from a formal inclusion at this time.


Issued at 434 AM CDT Wed Mar 14 2018

Regarding the fire weather situation TODAY:
It has been expected for days that we would at least see "near-
critical" fire weather conditions today, and for the majority of
the CWA that is the case. However, this latest forecast has nudged
down relative humidity (RH) and nudged up south-southwest wind
speeds JUST enough, that we are now expecting marginally-critical
parameters to be met within all or decent portions of the
following KS counties: Rooks/Osborne/Mitchell/Jewell. As a result,
a Red Flag Warning has been issued for these counties from 1-7 PM.
While bordering counties are obviously very close to critical
thresholds, they appear to have less potential to see 25+ MPH wind
gusts for 3+ hours. Relative humidity values are pretty solid,
with several hours of 15-20 percent looking likely in the Warning
area. To be honest, this is a fairly marginal Warning issuance, as
it may be tough to get 3+ hours of sustained winds/gusts of 20+
MPH/25+ MPH. However, based on what has happened a few times
within the last week when fire weather parameters ended up being a
bit worse than expected 8-12 hours out, decided to lean on the
cautious side this time around.

Regarding the fire weather situation THURSDAY:
East to southeasterly winds are expected to pick up in speed
during the day Thursday, thanks to deepening sfc low pressure
over eastern Colorado and a frontal boundary across northern KS.
Across our north central KS counties, warmer temperatures south of
the sfc front will be possible...though confidence in the exact
placement of the front isn`t the highest. If temps do climb up
into the 70s, with the gusty winds expected, near critical fire
weather conditions will be possible during the afternoon hours.

Closing with a quick review of our local fire weather criteria:
"Critical" means the 3+ hour overlap of relative humidity (RH) of 20-
percent-or-lower and sustained winds/gusts of 20+MPH/25+MPH (in
the presence of sufficiently-dry vegetation/fuels). "Near-
critical" means the overlap of 25-percent-or-lower RH and
sustained winds/gusts of 15+MPH/20+MPH.


KS...Red Flag Warning from 1 PM this afternoon to 7 PM CDT this
     evening for KSZ007-017>019.



SHORT TERM...Pfannkuch
FIRE WEATHER...Pfannkuch/ADP is the U.S. government's official web portal to all federal, state and local government web resources and services.