Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 141204
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
704 AM CDT Thu Mar 14 2024

...Aviation Update...

.KEY MESSAGES...

- The only precipitation chances (PoPs) featured in our entire
  7-day forecast consist of variable coverage of light
  rain/showers today into this evening. A few fortunate spots
  could pick up another 0.10-0.30", but this will likely be the
  exception.

- Although no days look particularly concerning for widespread
  critical fire weather conditions (at least yet), we are
  already forecasting at least near-critical combinations of
  wind speeds/low relative humidity each afternoon Sat-Wed so
  this will bear increased scrutiny with time.

- Although no days look overly-windy by March standards, most of
  the next week will feature at least breezy conditions, with
  the overall-strongest winds expected to be today and Sunday
  (gusts of 30-35+ MPH most favored), while Friday is favored to
  feature the overall-lightest winds of the next several days.

- Temperature-wise: Although not cold by any means for mid-
  March, the next several days will average out noticeably
  cooler than the very mild last several days. Highs mostly in
  the 50s will prevail today-Monday, before a more solid return
  to 60s is expected by Tues-Wed.

- For those who might have grown accustomed to our
  recent/ongoing stretch of above-freezing overnight low temps,
  please note that especially Sunday night will likely feature
  our next "hard freeze" well down in the 20s (the true spring
  growing season is not here yet).

&&

.DISCUSSION...
Issued at 516 AM CDT Thu Mar 14 2024

-- PRIMARY CHANGES TO THIS 7-DAY FORECAST PACKAGE VERSUS THE
 PREVIOUS ONE (issued Wed afternoon):

- Honestly, none of any particular note...just typical minor (a
  few degrees at most) tweaks to temps and an attempt to try to
  better refine light rain chances in these first 12-18 hours.


-- "BIG PICTURE" 7-DAY FORECAST OVERVIEW/COMMENTS (including
 all further discussion of the Saturday-Wednesday time frame):

- As was the case 24 hours ago, the latest ECMWF/GFS solutions
  remain in above-average agreement on the larger scale upper
  air/surface pattern through the next week (bolstering
  confidence in the going forecast). In short, our continued
  light rain/shower chances into this evening will be driven by
  a narrow, elongated ribbon of of a disturbance passing through
  in southwesterly flow aloft, which earlier ejected out of a
  larger upper low currently dropping southward over southern
  NV. Friday will be a transition day aloft, as the southwestern
  upper low becomes cut off over the Desert Southwest, while a
  northern stream trough starts driving south-southeastward out
  of Canada toward the Great Lakes/Midwest states. This will be
  our main influence aloft Sat-Mon, turning our flow north-
  northwesterly and ushering in a shot of cooler air for mainly
  Sunday (but not overly-cold with highs still at least low-mid
  50s most areas). By Tues-Wed this large scale troughing
  departs eastward, allowing our flow to become more zonal
  (west-east), which allows milder air to return from the
  west/south, and MAYBE also allows a disturbance to bring our
  next chance of rain around the Wed-Thurs time frame (HIGH
  uncertainty in this though).

- As touched on above, honestly our main concern through most of
  this next week will be monitoring fire weather conditions
  especially Sat-Wed afternoons. As it currently stands, we are
  only forecasting near-critical conditions each afternoon in
  parts of our coverage area (CWA)...meaning overlap of wind
  gusts 20+ MPH/relative humidity 25% or lower. However, fire
  weather parameters often tend to trend "worse" with time, so
  would not be surprised to see critical thresholds (combo of
  wind gusts 25+ MPH and RH 20% or lower) materialize with time.


-- SHORTER TERM FORECAST DETAILS FOCUSED SOLELY ON THESE NEXT
 48 HOURS (through Friday night):

- CURRENT/RECENT WEATHER SCENE AS OF 430 AM (including a recap
  of strong/severe storms over the last 12 hours):
Although a few rogue, weak thunderstorms are migrating across
mainly Mitchell County KS in our far southern CWA as I type
(likely the last true thunderstorm activity of this event),
things have settled down considerably from earlier in the
night/Wednesday evening. As was fully expected, we dealt with
our first round of severe storms this year, and also as
expected, this activity impacted only a small portion of our
CWA. More specifically, we issued 9 Severe Thunderstorm Warnings
entirely within our KS zones. If anything, the most intense
convection focused about 1 county south of where it was expected
to occur 24 hours ago, but we received several reports of hail
ranging from nickel to at least golf ball size in primary
Rooks/Osborne counties. This main round of storms actually
featured little to nothing in the way of severe-criteria winds,
but rather unexpectedly a fairly localized area of strong to
severe winds (at least 50-60 MPH) impacted parts of especially
Smith/Osborne/Jewell counties BEHIND the departing convection as
a "wake low" event transpired along the back/trailing edge of
stratiform rain (in short, this occurs due to descending air
warming and causing a localized/intense surface pressure
gradient). Although ground-truth reports of any possible damage
are limited, Smith Center KS airport reported gusts of 50-60+
MPH for roughly 90 minutes! Rainfall-wise, radar estimation and
various mesonet/airport stations confirm that parts of several
counties along/south of the state line received a widespread
0.25-0.75", with more localized 1+" amounts here and there, and
even more localized 2+" totals mainly in southwestern
Rooks/eastern Smith counties. Meanwhile, especially areas
near/north of Highway 6 have seen primarily well under 0.25" so
far.

Turning to the here and now, spotty patches of light
rain/sprinkles are ongoing in several Nebraska counties, while
other showers and the aforementioned "last gasp" of weak storms
in our KS zones will likely exit our CWA within the 30-60
minutes. Aloft, water vapor satellite and short term model data
reveal a narrow, southwest-northeast ribbon of vorticity
streaming overhead and prompting the rather hit-and-miss nature
of ongoing rainfall. At the surface, the center of low pressure
is over eastern KS, with northerly winds mainly sustained 10-15
MPH/gusts around 20 MPH across our CWA behind this departing
low. Low temps this morning are on track to bottom out no lower
than 40-48 degrees most areas given the winds and widespread
clouds.

- TODAY/DAYTIME INTO THIS EVENING (through around Midnight):
To summarize things as simply as possible, most areas will
likely be dry much of the day, but intermittent light rain/rain
showers (or at least sprinkles) just cannot be totally ruled out
anywhere at almost any time. Aloft, the elongated, gradually
shearing-out swath of lift/vorticity will persist, promoting
very transient and difficult to pinpoint bands/"blobs" of light
rain/sprinkles. with any lingering, very weak elevated
instability expected to depart our southern zones shortly, we
are not carrying any additional thunderstorm chances into the
daytime forecast period. Have attempted to refine rain
chances/PoPs to some degree, but this is honestly very difficult
in this kind of pattern (but all areas carry at least small
chances into this evening...albeit highest this morning and then
gradually decreasing this afternoon-evening). Additional rain
amounts in the vast majority of our CWA will likely average no
more than 0.10-0.25" (many places less and likely very few
more). In other departments, there is high confidence that it
will be an overall cloudy and blustery day, with especially mid-
morning onward featuring sustained north-northeast winds 20-25
MPH/gusts 25-35 MPH. High temps were nudged downward slightly
southeast and upward slightly north/west, but most of the CWA is
expected to hit fairly uniform highs in the 51-55 range.

- LATE THIS EVENING-OVERNIGHT:
Although cannot totally rule out a few rogue sprinkles hanging
on beyond midnight, the departure of the sheared out vorticity
zone and gradual drying of the mid-levels has prompted the
continuation of a dry post-midnight forecast CWA-wide, along
with at least partial clearing. Although winds will not be as
strong as this afternoon, steady north breezes sustained at
least 10-15 MPH/gusts 15-20+ MPH will persist through the night.
Although low temps will drop roughly 10 degrees colder than
this morning (most areas aimed 32-38), the steady winds will
keep them from bottoming out too far.

- FRIDAY DAYTIME:
All things considered, this will be one of the more pleasant
days of the next several, especially from a lighter afternoon
wind standpoint. Although some transient cloud cover will likely
persist into especially the morning hours, quite a bit of
sunshine should prevail in the afternoon, corresponding to a
decrease in wind speeds. During the morning, sustained northerly
winds of 10-15 MPH/gusts around 20 will continue, but as surface
high pressure noses in during the afternoon even gusts should
average under 15 MPH by mid-late afternoon. High temperatures
very seasonable for mid-March and very similar to today...with
mid 50s most areas.

- FRIDAY NIGHT:
Our forecast remains dry and with fairly high confidence. That
being said a few models (ECMWF/NAMNest) hint that a few rogue
sprinkles/light showers could TRY brushing at least near our KS
zones post-midnight (something to watch). Otherwise, this should
be a rather uneventful night under clear/mostly clear skies.
There will be a modest uptick in westerly winds especially post-
midnight (sustained 10-15 MPH/gusts 20+ MPH...especially north
of I-80). Despite the clear skies, these breezes will also keep
temps from crashing too far, with lows aimed 33-37 degrees most
of the CWA.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 704 AM CDT Thu Mar 14 2024

- General overview for KGRI/KEAR:
The vast majority of the period will feature no worse than low-
end VFR ceiling and VFR visibility, along with dry conditions.
However, periods of passing light rain showers (especially first
half of the period today) are likely, along with at least a few-
hours window of opportunity for MVFR ceiling. Wind direction
will be fairly consistent from a northerly to northeasterly
direction, with the strongest speeds (gusts up to around 30KT
most favored 15-01Z).

- Ceiling/precipitation details:
Right out of the gate this morning, steady light rain showers
are moving through the area, and at least spotty/intermittent
light showers and/or sprinkles will remain possible at almost
any time through at least 01Z (am carrying at least a generic
"vicinity shower"/VCSH to cover this). Confidence is high in
prevailing dry conditions by later this evening-overnight.
Ceiling-wise, although a low-end VFR ceiling is likely much of
especially these first 12 hours, at least a brief period (or
two) of MVFR ceiling cannot be ruled out...especially at KGRI.
For now, have indicated a prevailing VFR ceiling in the main FM
groups, but have TEMPO MVFR at KGRI 15-18Z as that appears to be
the most favored time frame for potential MVFR. While fleeting
patches of MVFR ceiling could pass through even during the
latter half of the period tonight, clouds should gradually
scatter out with high confidence in prevailing VFR overall.

- Winds:
Winds will prevail from a rather consistent northerly to
northeasterly direction throughout the period. The overall-
lightest speeds will occur during these first 3 hours and then
the final 6-9 hours late tonight (sustained around 12KT).
Meanwhile, the overall-strongest speeds will focus mainly 15-01Z
(sustained around 20KT/gusts around 30KT).

&&

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

&&

$$

DISCUSSION...Pfannkuch
AVIATION...Pfannkuch


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