Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 170134

Area Forecast Discussion
National Weather Service Pueblo CO
734 PM MDT Wed May 16 2018

Issued at 723 PM MDT Wed May 16 2018

Changes had to be made to the Red Flag Warning that is in effect
for Thursday. The status of the fuels changed this afternoon, and
fire weather zones 225 and 233 (the Sangre de Cristo mtns and
eastern Las Animas county) no longer have critical fuels and thus
a Red Flag Warning is not needed for these two zones and so we
will cancel the Warning. Also, taking a look at updated forecast
model data, it appears that El Paso county will meet Red Flag
criteria on Thursday afternoon and will therefore issue a Warning
for that area.


.SHORT TERM...(This evening through Thursday)
Issued at 351 PM MDT Wed May 16 2018

...Dryline Storms and Increasing Fire Danger...

Big, warm upper ridge over southern colorado this afternoon.  Warm,
subsident air aloft is capping most convection.  However, there is a
weakness in the cap across far southeast colorado.  This is allowing
a few cells to pop just south of the Baca County line over the OK
Panhandle at this hour.  Operational runs of the High Resolution
Rapid Refresh have a few more cells developing this vicinity through
the remainder of the afternoon into the evening hours. Experimental
runs are less excited.  Will keep some low pops going this vicinity
into the evening hours as activity is currently very close to
crossing over into our warning area (Baca County).  If a storm can
get going, possible hazards will include quarter-size hail, 60 mph
winds, locally heavy rain and lightning.  Quiet weather elsewhere
this evening.

On Thursday, fire danger will ramp up over much of the area as warm,
dry southwest flow sweeps across the region.  Gusty winds, low
humidity and dry fuels will once again be the culpret.  This will
primarily impact the southwest mountains, southeast mountains and
Las Animas County.  However, near critical conditions will be
possible just about anywhere.  Outdoor burning or any other
activities that could accidentally start a wildfire should be
postponed for a better time.

The increased southwest flow will help to tighten the dryline along
the eastern Colorado border in the afternoon.  It`s looking more and
more promising for dryline thunderstorm development somewhere in the
vicinity of the Kansas border late tomorrow afternoon.  Where
exactly the development will occur is the big question.  Will the
storms start up in Colorado and then move into Kansas or will they
start up in Kansas.  Based on today`s runs, it looks like we should
see at least some development in Colorado before moving into Kansas.
Right now, eastern Kiowa, Prowers and easern Baca counties look like
prime targets.  If storms do develop, they will definitely have
severe potential.  All the elements will be there... huge CAPE,
ample instability and plenty of shear.  Could be some big ones along
the border late Thursday afternoon.

.LONG TERM...(Thursday night through Wednesday)
Issued at 351 PM MDT Wed May 16 2018

Thursday night-Friday night...Moderate south to southwest flow loft
across the region Thursday night and Friday becomes more west to
northwest later Friday and into Friday night, as a broad upper
trough translates across the Rockies. Models continue to suggest a
dry line out across the far Southeast Plains late Thursday afternoon
and evening, and have kept mainly isolated pops in tact along the
western Kansas border through the evening. Any storms that do
develop could be strong to severe, producing large quarter sized
hail and gusty outflow winds of up to 60 mph. Induced lee low across
the Plains helps to bring some low level moisture back south and
west across the Southeast Plains into early Friday morning, with the
low expected to lift back north and east across Colorado Plains
Friday afternoon and evening, as upper trough continues across the
Rockies. Current model projections have best low level moisture
lifting just north of the area Friday afternoon across the Northeast
Colorado Plains, where latest SPC Day 3 outlook has a slight risk of
severe storms, with a marginal risk along and just north of the
Palmer Divide. Model blended pops has best pops for Southeast
Colorado along the Palmer Divide and I have also brought slight
chance pops down as far south as the Highway 50 Corridor, as the
latest NAM is not as strong with the induced low and keeps a ribbon
of CAPE across northern portions of the Southeast Plains on Friday.
At any rate, will need to monitor future models for severe weather
potential across the Plains on Friday, as well as the potential for
critical fire weather conditions across extreme southern portions of
the plains on Friday afternoon as well. Temperatures on Friday will
be tricky and dependent on placement of said low, and have stayed
close to a blended solution with highs in the upper 70s to upper 80s
across the lower elevations, with the warmest readings across the
far southeast plains.

Saturday-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 Sunday ahead
of more energy digging into the Great Basin. Passing Rockies trough
sends its  associated cold front across Eastern Colorado late Friday
night and early Saturday, supporting breezy northerly winds and
cooler temperatures on Saturday, with highs across the Plains
expected to be some 15-20F colder than Friday and mainly in the 60s
to lower 70s. Latest models indicating steep lapse rates and some
moisture in place to support scattered showers and thunderstorms
developing across the higher terrain on Saturday, 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
across the higher terrain, with a few possible storms moving across
the Plains through the evening.

Monday-Wednesday...Lower confidence in the later part of the forecast
as latest models differ on timing and location of energy ejecting
from parent trough across the Great Basin in this timeframe. Pattern
suggests warmer weather with the potential for diurnal convection,
and have kept pops mainly over the higher terrain at this time.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 351 PM MDT Wed May 16 2018

Upper ridge over Colorado this afternoon. Isolated storms will be
possible over the far southeast Colorado plains this evening, primarily
over Baca and Prowers Counties. If storms develop, they could produce
quarter size hail, 60 mph wind gusts, locally heavy rain and lightning.

Thursday afternoon, a dryline will strengthen along the Kansas border
in the afternoon.  This will lead to possible severe thunderstorms
along and near the Kansas border late in the day.

Otherwise, VFR expected across the rest of the flight area through
Thursday. This includes the KCOS, KPUB and KALS terminals.


Red Flag Warning from noon to 8 PM MDT Thursday for COZ223-226-



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