Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 211037

Area Forecast Discussion
National Weather Service Hastings NE
537 AM CDT Fri Oct 21 2016

.SHORT TERM...(Today and tonight)
Issued at 420 AM CDT Fri Oct 21 2016

Today...An upper level ridge will build across the high plains
region today into tonight. After some morning cirrus clouds expect
clearing skies, warm southerly winds, and highs back into the mid
and upper 60s for most areas to around 70 over north central Kansas.
The wind could be a bit breezy out of the south southwest from late
morning through mid-afternoon at 15 to 20 mph gusting to around 25
mph mainly east of highway 183. The wind will be lighter to the west
of highway 183 where a sfc trough axis will be located.

Fire weather...RH values should fall into the 20-25 percent range
west of highway 183, but the wind will also be fairly light in that
area due to the above mentioned trough axis.

Tonight...The wind will die down and skies should be clear to mostly
clear. Therefore, expect good radiational cooling with a big diurnal
temperature spread. Temperatures could be a bit frosty in some areas
such as Ord to Lexington where lows will fall into the lower 30s.
Elsewhere lows should range from the mid 30s to around 40.

.LONG TERM...(Saturday daytime through Thursday)
Issued at 420 AM CDT Fri Oct 21 2016

The one-sentence summary of this 6-day period:
The vast majority of this time will feature dry and seasonably-
mild conditions with the only chances for rain/thunderstorms
(albeit a potentially decent chance for some) arriving
Tuesday/Tuesday night.

General overview:
Overall, those closely watching forecast trends will see very
little noticeable change between this cycle and the previous one.
Of the few minor tweaks that were made, one included the removal
of thunderstorm chances from our eastern zones on Monday night
(delayed until Tuesday) and another involves a roughly 3-degree
drop in high temps for Wednesday, although these temp specifics
are still far from set at this Day 6 range. Overall though,
there are essentially only 2 "highlights"/concerns to speak of: 1)
The likelihood of "near-critical" fire weather conditions on
Saturday afternoon (see separate "Fire Weather" section below for
any further discussion of this topic) and 2) a fairly quick moving
disturbance that brings our next legitimate chance of
rain/thunderstorms during the Tuesday/Tuesday night time frame.
Based on the latest trends, it still appears that the eastern half
of the CWA stands an overall-better chance of seeing rain than the
western half, and in fact precip chances (PoPs) are already as
high as 50-60 percent for Tuesday night in roughly the eastern 1/4
of the CWA (would normally not be too comfortable with PoPs that
high out in the Day 5/6 range but at least for now halfway decent
model agreement supports it). It`s still too soon to get caught up
in thunderstorm intensity details, but taking the latest
GFS/ECMWF instability/shear progs at face value suggests that this
could be a future candidate for a possible Marginal Risk of
strong-to-severe storms as it gets closer in time. Switching gears
to temperatures, considering that our average daily highs are
generally in the low 60s and average lows in the mid-upper 30s, we
have little to complain about given that each of these 6 days has
highs generally aimed between the mid-60s to mid-70s and lows
mainly in the 40s. The overall-warmest day still looks to be
Saturday with highs aimed mid-upper 70s most areas, while the
overall-coldest night currently looks to be Sunday night with most
places a few degrees either side of 40. In other words, we will
continue a rather prolonged streak of  the majority of the CWA
avoiding sub-freezing temps since our last widespread freeze back
on the 13th.

With the main points covered, will end with some day-to-day
specifics for those interested...

Saturday/Sat. night:
With the main jet stream well to our north near the Canadian
border, broad, low-amplitude ridging dominates the Central Plains,
paving the way for a mostly clear and guaranteed dry 24 hours. As
mentioned, this looks to be the warmest day of the next 7 with
highs well into the 70s most places, and maybe a few 80s far
southwest. At the surface, although probably just a few MPH
lighter than today, a modest pressure gradient will still promote
somewhat breezy south winds of at least 10-15 MPH/gusts to around
20 MPH or slightly higher (again, see separate section below for
fire weather concerns). Saturday night, a weak cold front will
slide southward into the area late, turning breezes northerly.

Sunday/Sun night:
Broad ridging aloft continues to promote essentially zero risk of
rain. Behind the passing front, high temps look to average roughly
3-5 degrees cooler than Saturday, as winds average 10-15 MPH from
a northerly-to-easterly direction during the day.

Monday/Mon night:
Breezes flip back around out of the south-southeast in advance of
a quick-moving shortwave trough that starts undercutting the mean
ridge and approaching from the west. High temps a bit cooler than
Sunday, only aimed mid-60s to low 70s for most. Confidence
remains pretty high in a dry day and the latest model blend used
to populate the extended forecast removed our previously-
advertised rain chances for Monday night. That being said, it
could be a close call here, as a consensus of the ECMWF/GFS/GEM
bring Monday night storm chances perilously close to our
northern/eastern edges.

Tuesday/Tues night:
All mentionable (15+ percent) PoPs in the entire 7-day forecast
are confined to these 24 hours as the aforementioned shortwave
trough slides across the heart of the Central Plains and
amplifies a bit as it does so, dragging through a weak surface
cold front in the process. As already mentioned, the highest
rain/thunderstorm chances along this front currently look to
focus in the eastern CWA, and there could even be a small severe
risk, but these details are still plenty subject to change.

The latest ECMWF/GFS runs are in pretty decent agreement by Day
6-7 standards in bringing a return to solidly dry conditions as
broad ridging again becomes the dominant feature aloft. While high
temps are officially aimed a few degrees either side of 70, there
is currently some noticeable model disparity for Thursday`s highs
between the latest deterministic runs of the two primary models,
with the latest GFS suggesting a one-day upward surge to around
80 is possible.


.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Saturday morning)
Issued at 528 AM CDT Fri Oct 21 2016

Low level wind shear will be near, but just below criteria for
inclusion in the TAF through 16Z. Expect a southwesterly low level
jet at around 35kts at around 400 ft agl through around 10 or 11
am. VFR ceilings and visibility are expected to continue
throughout the TAF valid period. There will be some scattered high
clouds around primarily this morning, but nothing that will cause
problems. The wind should predominately be out of the south or
south southwest and could be a bit breezy during the late morning
and afternoon hours. The wind is expected to quickly die down
around and after sunset.


Issued at 420 AM CDT Fri Oct 21 2016

Regarding Saturday afternoon:
Now that is only 2 days away, confidence continues increasing
that Saturday afternoon will feature at least "near-critical" fire
weather conditions mainly in counties along and especially west of
the Highway 281 corridor. These areas are most likely to observe
an overlap of relative humidity (RH) of 20-25 percent and
sustained south winds roughly 15-20 MPH with gusts up to around 25
MPH. Digging a bit deeper into the numbers, the overall-worst fire
weather conditions (perilously close to "critical" in fact) should
in theory focus in our far northwestern counties such as
Valley/Sherman/Dawson. Not surprisingly, this same area is
highlighted by SPC in an "Elevated" risk on the latest Day 2 Fire
Outlook. All things considered, although we cannot completely rule
out future forecasts trending worse/into critical territory,
confidence is currently not there to justify a 3rd period Fire
Weather Watch. However, we will continue to highlight near-
critical expectations in the Hazardous Weather Outlook (HWOGID).

Fortunately, beyond Saturday, there are no afternoons in the
7-day that currently (key word "currently") appear to feature
appreciable fire weather concerns.

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




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