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Area forecast discussion
National Weather Service Hastings NE
645 PM CDT sun Jun 25 2017

Short term...(this evening through Monday night)
issued at 405 PM CDT sun Jun 25 2017

The overall-theme of not only the short term but also the long
term story has changed very little over the past 12-24 hours. Will
cover the longer-term situation more below, but by far the bottom
line is that we will be returning to a warmer/more humid/active/
Summer weather pattern over the upcoming week, with several
chances for thunderstorms and probably at least a few severe storm
events.

Focusing solely on these next 36 hours of the "short term", we
have one more day of slightly-cooler and drier/less humid than
normal air in store before more "true" Summer heat returns. While
there are small chances for thunderstorms, the threat of severe
storms appears rather low (especially through Monday morning),
but then potentially ramps up a little during the
afternoon/evening. We have noted that Storm Prediction Center has opted to introduce a
marginal risk for Monday afternoon/evening in a portion of our
north central Kansas coverage area (cwa), and while this may
ultimately prove justified, there is enough variability in model
instability progs between the usually-more-unstable NAM and the
more conservative GFS that this forecaster is not truly "sold" yet
on a Monday severe risk. That being said, will at least carry
"strong storm" potential in local products such as the hazardous
weather outlook, and defer to next few shifts to adjust the threat
level if needed.

Taking a quick look at the current/recent weather scene as of 330
pm: much of mainly the southwest half of the County Warning Area has seen at least
a brief sprinkle/light rain shower since sunrise, with especially
Kansas zones seeing one or more rounds of steadier light rain and
perhaps even a few rumbles of thunder. While much of this initial
precip has exited our domain, another small area of weak
convection is approaching our Kansas zones from the northwest at this
time. This weak, elevated activity is being driven by modest mid-
level forcing associated with a mid level wave passing through in
continued northwest-flow aloft. Visible satellite clearly reveals
plentiful sunshine has broken out this afternoon across most
Nebraska zones, with considerably more cloud cover in Kansas.
Dewpoints/humidity have been a little lower than anticipated
especially under the sunny areas, with dews as low as the upper
30s-low 40s making for very comfortable conditions, especially
given such light/variable winds with most places 10 miles per hour-or-less
thanks to broad surface high pressure. High temps are on track to
top out 72-77 most areas, although persistence cloudiness in parts
of our Kansas zones could keep some places in the 60s.

Now briefly glossing over forecast expectations through these next
3 forecast periods...

Late this afternoon through tonight:
while the vast majority of the County Warning Area will remain dry through tonight
(especially through midnight), have maintained some low
shower/weak thunderstorm chances mainly near and south of the
state line through roughly midnight. Then late in the night and
toward sunrise, a small chance (mainly 20 percent at most) of
rain/weak thunderstorms expands to include the entire outlook
area, as meager elevated instability expands northeast along a
southwesterly low level jet axis. Breezes tonight will average
5-10 miles per hour from a south or southwest direction. Though not
officially included in the latest forecast, there is a "non-zero"
chance of at least light/patchy fog tonight especially in southern
zones, possibly enhanced by the wet ground from today's light rain
activity. This will be something for evening/night shift to watch
in case confidence in any fog increases. Low temps are aimed low-
mid 50s most areas.

Monday daytime-night:
yet another disturbance will pass through in northwest flow aloft,
promoting at least a small chance of shower/thunderstorm
development at almost any point during the day, with chances
gradually fading southward into Kansas (ending from north to south)
during the afternoon-evening. Have already discussed above that
especially southern zones could be favored for a line/cluster of
stronger storms during the afternoon-evening, focused in the lower
levels by a weak passing cold front that will switch winds from
westerly, to northerly, to easterly over the course of the day and
evening. For the late night hours, the vast majority of the area
should remain dry. Assuming that clouds are not overly-abundant,
high temps are aimed a touch warmer than those of today, with
mainly a 78-82 range. Daytime breezes will be a little stronger
than today (especially afternoon), but sustained speeds should
still only be 10-15 miles per hour.

Long term...(tuesday daytime through sunday)
issued at 405 PM CDT sun Jun 25 2017

Admittedly, not enough time today to give this 6-day period proper
Justice, especially in terms of day-to-day details, so be sure to
check later discussions for those, but will at least hit the most
important highlights/take-away messages:

1) by far the biggest story is a return to a warmer more
humid/unstable airmass with increasing chances for periodic
strong to severe thunderstorm activity. Storm Prediction Center already has much of
the County Warning Area in a formal marginal or slight risk for Tuesday evening
(note that this will mainly be an after-7pm threat as the daytime
should by dry and windy). While the day-to-day details of severe
weather potential in this quasi-zonal flow pattern will be tricky
to discern, fully expect additional severe risks to be introduced
for days such as Thursday and perhaps Wednesday/Friday as well as
they get closer. Mainly a damaging wind/hail threat with severe
events, but as always smaller scale features will need watched for
isolated tornado potential.

2) on a positive note, for those wanting a "decent" rain as most
folks are, the potential is there for much of the County Warning Area to receive
a widespread 1-2" and locally higher over the course of the
upcoming week.

3) temp-wise: high temperatures Tuesday will be mainly mid-80s
with readings closer to 90 Wed-thurs before easing back generally
mid-80s again Fri-Sat. Along with the heat, the return of dewpoint
in the 60s for mid-week will be quite noticeable after our recent
"taste of fall".

4) for those particularly concerned with winds, the windiest day
of the week appears to be Tuesday, with sustained south winds at
least 15-25 miles per hour and gusts at least 30-35 miles per hour out of the south.

&&

Aviation...(for the 00z kgri/kear tafs through 00z monday)
issued at 635 PM CDT sun Jun 25 2017

Prevailing VFR conditions are anticipated through the period
although there will be a small chance for some showers or
thunderstorms across south central Nebraska beginning during the
early morning hours. Despite the low probability...opted to
include the mention of a thunderstorms in the vicinity at both terminal from 26/10z-26/18z
as models are trying to generate some spotty qpf during this time
period. Overall...winds will be light...and shifting from
southerly to more northerly by the end of the period as a weak
frontal boundary drops south across the area. With the best
forcing associated with the approaching cold front is to our
east...opted to not include a vcsh or thunderstorms in the vicinity beyond 26/18z.

&&

Gid watches/warnings/advisories...
NE...none.
Kansas...none.
&&

$$

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