700
FXUS63 KGLD 171701
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1101 AM MDT Fri May 17 2024

.KEY MESSAGES...

- Tranquil but warm weather continues today. A 10-15% chance of
  a thunderstorm does exist this afternoon between Goodland and
  McCook.

- Active pattern then begins Saturday night through at least mid
  week with the potential for torrential rainfall and severe
  weather nearly each day.

- Low (10-15%) chance of frost Wednesday morning currently
  favoring eastern Colorado.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 208 AM MDT Fri May 17 2024

Surface trough is moving into the area from the north bringing
some upper level cirrus along with it. WSW winds will be present
for much of the day bringing with it warm temperatures for the
entire area including some low 90s thanks in part to
downsloping. A surface convergence boundary looks to be across
the area roughly from a Goodland to McCook line this afternoon
which may bring the potential for a rogue thunderstorm along it.
Inverted v soundings will be in place across nearly the entire
area which if a storm does form think an isolated damaging wind
threat due to downbursts would be the most likely outcome.
Rainfall may be difficult to come by if something were to
develop as virga may be all that would be in play. Opted to go
silent pops (10-14%) for today due to concerns regarding virga
and if development will even occur in the first place.

Saturday will see a weak cold front clip northern portions of
the area during the morning hours with nothing but a wind shift
the NNW being the most noticeable feature with this front. A
surface high then sets up across Nebraska which will turn our
winds to the east allowing moisture advection to move into the
area. This will be important as this will help fuel evening and
overnight thunderstorms. GFS and NAM are both bullish on
moisture being available with PWATS well in excess of an inch
across the majority of the area. Despite the high PWATS think
any flooding potential will be minimal as Corfidi vectors are in
excess of 25-35 knots both upstream and downstream. With
easterly upslope flow present with ample moisture think any
flooding threat would be back building and training over certain
locales. An isolated severe storm mainly for large hail can`t
be completely ruled out especially if the NAM verifies which is
the most aggressive with MUCAPE in excess of 2000 j/kg and 0-6
shear of 35 knots.

This will all be setting the stage for Sunday. A longwave
trough will be present with an embedded wave ejecting during the
afternoon. Triple point looks to be set up across W Kansas;
guidance is not currently agreeing on the exact placement but
using the NAM which has handled similar setups fairly well thus
far this spring would put the dryline down in SW Kansas and
nearly the entire CWA in the warm sector with the warm front
draped roughly along Highway 34 in SW Nebraska. This will be
setting the stage for the areas next organized severe
thunderstorm threat. All hazards are possible, but currently am
thinking large hail, potentially in excess of 2 inches would be
the primary threat with MUCAPE in excess of 2500 j/kg, steep
lapse rates and favorable EBWD in excess of 40 knots. Hodographs
look to mainly straight line which supports hail and storm
splits. There does appear to be a slight elongation around 00Z
Monday as the LLJ increases which may be the window for any
tornado threat. Do think this would favor mainly the triple
point intersection at this time. PWATS will also be fairly high
in excess of inch which again may pose a limited hydro threat
especially if heavy rain does occur Saturday night into Sunday.
Depending on where the dryline does set up may see some fire
weather potential behind it.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Issued at 208 AM MDT Fri May 17 2024

The active pattern then looks to continue into the extended
period as well. Moisture looks to remain in place throughout the
day Monday. Another surface low looks to develop across SW
Kansas throughout the day Monday with the longwave trough from
the previous day ejecting out another wave. Severe weather may
again be on the table with two rounds in the realm of
possibility with the first energy ejection, then a potential MCS
or squall line moving NW to SE across the area during the
evening hours. With potentially three consecutive days of heavy
rain potential flooding may continue to pose an issue. However
again, Corfidi Vectors do not support classic widespread
flooding concerns.

Continued daily chances for showers and storms continue through
the remainder of the period. Shear thus far does continue to
appear to remain in place which suggests that some severe threat
may present itself each day; although exact location, timing,
specific hazards are to far out to say with enough certainty at
this time.

Temperatures for the extended period do appear to start off
near to below normal with highs in the 60s to 70s on Tuesday and
then slowly warming back into the 70s to 80s towards the latter
portion of the weak. A cold front, fairly strong for mid to
late May looks to move through the area Tuesday night and into
Wednesday morning dropping lows into the upper 30s to low 40s
for most of the area. Do have some concerns about clouds
clearing out along with light winds which may make it cooler. If
the precipitation forecast through Wednesday morning does pan
out then some concern for frost, especially in low lying areas
mainly across eastern Colorado as lighter winds, clear skies and
ample moisture would support the development. Confidence in
frost at this time is less than 15% as some guidance does
suggest clouds and even rain continuing Wednesday morning which
would eliminate any frost threat. It is worth mentioning however
the potential as the entire area is past its average last
freeze date and most to all vegetation is now susceptible to
frost damage.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1100 AM MDT Fri May 17 2024

VFR conditions will rule through the TAF period, with ceilings
confined to cirrus ar or above ~12 KFT AGL. 10-15 knot SW to WSW
winds will prevail this afternoon, backing to the SSW to S
after sunset. Southerly LLWS is anticipated tonight -- in
association with the development of a 40-50 knot southerly low-
level jet ~05 UTC. Southerly LLWS will abate by sunrise -- as
surface high pressure builds southward into the region and
surface winds shift to the N at 15-25 knots (via rapid pressure
rises, ~5 mb/~3 hours). After the aforementioned pressure rises,
winds will weaken to 7-12 knots and veer to the NE (late Sat
morning) and E (Sat afternoon).. as surface high pressure
progresses eastward from Nebraska to the Iowa border.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.

&&

$$

SHORT TERM...Trigg
LONG TERM...Trigg
AVIATION...Vincent