Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 180007

Area Forecast Discussion
National Weather Service Pueblo CO
607 PM MDT Thu May 17 2018

Issued at 606 PM MDT Thu May 17 2018

Updated for cancellation of Severe Thunderstorm Watch for Prowers
and Baca counties.


.SHORT TERM...(This evening through Friday)
Issued at 346 PM MDT Thu May 17 2018

...A Few Severe Storms Possible East This Evening with More Severe
Potential including the Pikes Peak Region on Friday...

It`s starting to behave like spring out there.  So far, we`ve had 1
elevated supercell trying to get connected to the surface.  But thus
far, this hasn`t happened.  Strong flow aloft has been moving the
cell along, shearing it and leaving it unable to connect.  However,
as the afternoon/evening progresses, it may have increasing success
as it moves into better/deeper moisture gradient and backing low
level flow.  Per collaboration with impacted forecast offices, SPC
has hoisted a Severe Thunderstorm Watch for Prowers and Baca
Counties until 9 pm this evening.  While the watch is for those 2
counties, the eastern half of Kiowa County may also get in on the
action this evening before storms move off into Kansas.  The primary
weather hazards this evening will be hail up to the size of half
dollars, wind gusts over 60 mph, locally heavy rainfall and
lightning.  Elsewhere, the main concern will be the fire danger.  A
Red Flag Warning will remain in effect until 8 pm this evening.
Outdoor burning or any other activities that could accidentally
start a wildfire should be postponed until a better time.

On Friday, a cold front will make a move south into eastern Colorado
during the afternoon.  This will "up the ante" in the both the
thunderstorm and severe potential department, particularly across
the Pikes Peak Region late in the day.  El Paso County will be under
the best frontogenetic forcing late Friday afternoon, combined with
good low level upslope flow into Pikes Peak and the Rampart Range.
Some of the latest runs are dropping the front a lot farther south
than previous runs, down south of the Arkansas and Highway 50.  If
this happens, there could be a lot more convection, a lot farther
south than previously thought.  Also, the severe potential could be
a lot farther south.  It could include areas generally along and
north of the Highway 50 corridor.  Not certain right now.  Will
need to wait for later model runs to call it with more certainty.

.LONG TERM...(Friday night through Thursday)
Issued at 346 PM MDT Thu May 17 2018

Friday night through Sunday...Broad upper trough continues to lift
north and east across the Rockies Friday night and Saturday with
more west to southwest flow aloft developing across the area through
the day Sunday, ahead of more energy digging into the Great Basin.
Some differences with the strength of the Friday night/Saturday
system, with the GFS the strongest and furthest south with a mid
level circulation developing across northeastern Colorado Friday
night which slowly slides south and east into west central Kansas
through the day Saturday, where as the EC is weaker and further
north with this circulation and the latest NAM is in between these
two solutions. The GFS solution is the most bullish with
precipitation for Southeast Colorado, especially with wrap around
precipitation for areas north of the Highway 50 Corridor on
Saturday, where as the NAM and the EC, keep the best precipitation
along and north of the Palmer Dvd Friday night and Saturday, and
have have trended the forecast towards this solution.

At any rate, will still have the potential for severe storms along
and north of the lower Arkansas River Valley Friday evening, with
large hail and strong outflow winds the main threats. Will see
northerly developing across the Plains Friday night as induced
surface low lifts north and east across the Plains, with breezy
northerly of 15 to 30 mph and much cooler temperatures expected on
Saturday, with highs across the Plains expected to be some 15-20F
colder than Friday, mainly in the 60s to lower 70s. Should see
scattered showers and thunderstorms developing across the higher
terrain late Saturday morning and continuing through the early
evening, with storms weakening as the push east into a more stable
atmosphere across the Plains. Slightly warmer temperatures across
the area on Sunday will lead to another round of scattered afternoon
and evening showers and storms over and near the higher terrain,
with a few possible storms moving across the Plains through the

Monday-Thursday...Models continue to indicate energy digging into
the Great Basin through the period, though also differ on timing and
location of energy ejecting from parent trough across the Great
Basin through out this timeframe. Pattern does suggest warmer
weather with temperatures generally above seasonal levels through
the period. Pattern also suggest the potential for diurnal convection,
and have kept the best pops over the higher terrain at this time.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 346 PM MDT Thu May 17 2018

VFR most of the area through 18z Friday. This includes the KCOS,
KPUB and KALS terminals. However, there will be some isolated
thunderstorms, some possibly severe, across the far eastern plains
this evening. The primary hazards from most storms will be small
hail, wind gusts to around 50 mph and lightning. However, one or two
storms could become severe producing half dollar size hail, wind
gusts over 60 mph and heavy rain. The severe weather is most likely
to occur along and east of a line from Eads through Lamar and

After 18z on Friday, a cold front will begin to move into northern
parts of the flight area.  This front will likely spread south
across the Palmer Divide and El Paso County during the afternoon.
Showers and thunderstorms, some possibly severe, will then develop
across El Paso County and the Pikes Peak Region late in the day.
There are some late indications that the front may move even farther
south to at least the Highway 50 corridor.  The KCOS terminal will
likely see showers and storms develop after about 21z. KPUB has a
smaller chance of seeing showers and storms after 21z. KALS will
likely remain thunderstorm-free through the forecast period.


Red Flag Warning until 8 PM MDT this evening for COZ223-226-227-



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