National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KGID 150030 CCA
AFDGID

Area Forecast Discussion...CORRECTED
National Weather Service Hastings NE
730 PM CDT Sun Apr 14 2024

...Aviation Update...

.KEY MESSAGES...

- Strong southeast winds (gusts to 45 MPH) through Monday

- Scattered thunderstorms Monday evening through Monday night.
  Some of these are expected to be severe. Hail is the primary
  threat, with some threat for damaging wind and tornadoes as
  well.

- Continued rain/thunderstorm chances on Tuesday, with strong
  northwest winds (gusts 50+ MPH) through Tuesday night.

- Cooler late this week into the weekend. Sub-freezing low
  temperatures are likely, especially Saturday night.

&&

.DISCUSSION...
Issued at 330 PM CDT Sun Apr 14 2024

The main concern in this forecast period is a strong upper low
that will bring a variety of weather hazards to the area Monday
through Tuesday.

This system will cross the Rockies late tonight into Monday
morning, with moisture returning ahead of it through the day on
Monday. By afternoon, southeasterly surface winds of 25 to 35
MPH are likely, with gusts up to 45 MPH.

As temperatures climb into the 80s and moisture continues to
return MLCAPE values will climb over 2000 J/kg across much of
the forecast area during the afternoon. Effective shear of
30-40kts will be sufficient for supercell structures, and CAMs
show a few storms developing near the warm front in the 6-8pm
timeframe. The favored initiation point is in our north and
northeast. Most convection SHOULD hold off until at least 6pm.
That said, there still quite a bit of uncertainty on mesoscale
details/timing at this time.

This initial round of storms will push to the north/northeast
relatively quickly, with additional rounds of thunderstorms
developing as better upper forcing arrives from the west. Again,
details remain uncertain on exact placement, but CAMs indicate a
broken line of thunderstorms pushing west to east across
portions of the area late into the overnight (roughly 10pm to
3am). Large hail and damaging wind will be the main threat, but
a few tornadoes will remain possible. This is not a
climatologically favorable time for tornadoes, but the threat
will continue as long as storms can stay based near the surface.
Increasingly strong low-level shear may push STP values over 4 (at
least on a localized basis) ahead of this line.

This round of convection pushes to our east on Tuesday, though
additional rain and thunderstorms remain possible underneath and
west of the low. The main severe threat appears to be safely to
our east, but there will be enough remaining instability for a
few storms to become strong to marginally severe.

Winds turn to the northwest Tuesday into Tuesday night. Gusts
over 50 MPH appear possible, but it looks unlikely that we will
reach high-wind criteria at this time.

Beyond Tuesday, no changes were made to the NBM initialization.
The next chance for precipitation is Wednesday night. This will
be mainly rain, but some snow cannot be ruled out in northern
zones as colder air moves in.

Speaking of colder air, temperatures Thursday through Sunday
are expected to be 5-15 degrees below our climatological
normals. The coldest day appears to be Saturday, with highs only
in the upper 40s and 50s and overnight lows potentially dipping
into the 20s for some.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 723 PM CDT Sun Apr 14 2024

- General overview for KGRI/KEAR:
By far the overall-biggest story will be steadily-strengthening
southeast winds especially during the latter half of the period
(along with a round of low level wind shear/LLWS overnight
tonight). Otherwise, confidence is currently high in at least
the vast majority of the period featuring VFR ceiling/visibility
and rain/thunderstorm-free conditions. However, especially the
final few hours (21-00Z) bring some uncertainties/question marks
into play.

- Ceiling/precipitation trends:
Starting with ceiling, confidence is high in continued VFR (in
fact very little cloud cover whatsoever) through at least
18-21Z. Thereafter, at least a scattered to perhaps broken lower
cloud deck is very possible. The majority of guidance supports
any possible ceiling being no lower than low-end VFR (around 4K
ft.), but suppose MVFR cannot be completely ruled out depending
on how robust low-level moisture return is. Have kept TAFs VFR
for now.

As for rain/thunderstorm chances, there is also high confidence
in nothing through at least 21Z. However, there is at least a small
(20-30%) chance that isolated (and possibly severe) storms
could erupt in the general area sometime toward the final few
hours of the period. However, with this chance so low and with
better thunderstorm chances expected to arrive later in the
evening, have held off introducing any formal thunderstorm
mention during this valid period.

- Wind details (including LLWS):
- Surface winds:
The overall-lightest winds of the period will occur this
evening-overnight (sustained speeds generally 10-15KT/gusts
15-19KT out of the east. Then, the latter half of the period
will gradually become downright windy as direction trends more
southeasterly, with sustained speeds by mid-late afternoon at
least 25-30KT/gusts at least 35-40KT.

- LLWS:
Have introduced an 8-hour LLWS group from 06-14Z to highlight
several hours that will likely feature a 30+ KT shear magnitude
between the surface and mainly 1,500 ft. AGL. This will be due
to southeasterly winds above the surface accelerating to at
least 40-45KT.

&&

.FIRE WEATHER...
Issued at 330 PM CDT Sun Apr 14 2024

MONDAY:
As mentioned above, southeasterly winds will increase on
Monday, with gusts solidly in the 35-45 MPH range through the
afternoon. Sufficient moisture will return to most of the region
to avoid a critical fire threat, but the dryline may push into
our far west. There is still quite a bit of uncertainty on its
location. Areas west of the dryline could see easily see
humidity in the low teens for several hours, but areas to the
east may struggle to dip much below 35 percent. Because of this,
we opted for a Fire Weather Watch rather than going with a
Warning, and hopefully it becomes more clear whether to upgrade
or cancel based the 00Z guidance tonight.

&&

.CLIMATE...
Issued at 723 PM CDT Sun Apr 14 2024

Despite the recent well-above normal warmth that will continue
into early this week, all daily temperature records have remained
"safe" so far at Grand Island/Hastings airports (the two
stations for which we issue formal Record Event Reports/RERs).
However, it still appears we have a chance of at least
approaching the existing record warm low/minimum temperature
for Tuesday (April 16th).

- RECORD WARM LOW TEMPS AND LATEST FORECAST (Tues April 16th):

GRAND ISLAND
Current record:   54 (2006)
Current forecast: 51 at 11:59 PM Tues night

HASTINGS
Current record:   57 (2016)
Current forecast: 51 at 11:59 PM Tues night

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Fire Weather Watch from Monday afternoon through Monday
     evening for NEZ082.
KS...Fire Weather Watch from Monday afternoon through Monday
     evening for KSZ005-017.

&&

$$

DISCUSSION...Mangels
AVIATION...Pfannkuch
FIRE WEATHER...Mangels
CLIMATE...Mangels/Pfannkuch