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Area forecast discussion 
National Weather Service Pueblo Colorado
423 am MDT Tuesday may 5 2015

Short term...(today and tonight)
issued at 340 am MDT Tuesday may 5 2015

..another active day on tap...

Currently...the upper low pressure system was over Arizona and nearing
the 4 corners...drawing abundant moisture up across eastern nm and
the panhandles...into Colorado and Kansas. Bands of showers continue to stream
across the plains...while some of the Montana locations were reporting
snow. As of 4 am temperatures have hovered in the 40s to lower 50s.

Today and tonight...the upper low is forecast to track across the 4
corners this morning...then across Colorado through the day before
weakening and exiting to the northeast late tonight. This will help
to continue widespread showers and scattered thunderstorms across
the forecast area...and especially to the east mts and east plains. The
best window for heavy rain looks to be between 15z and 03z...when a
lobe of energy rotates across the County Warning Area. A deep southerly feed will
continue to advect moisture in through the middle part of the day.
Given the amount of rain that has already fallen in Teller and El
Paso counties recently...feel that the Flash Flood Watch for those
counties for today until 6 PM looks good. As is expected...the Waldo
Canyon and Black Forest burn scars will be the most susceptible to
flash flooding.

Storm Prediction Center has much of the southeast plains outlooked for marginally severe storms
once again today. Cape values are forecast to be in the 1000 to 1500
j/kg range...though bulk shear is not all that impressive.

Finally...there is the potential for 2 to 5 inches of new snow
accumulations over the high mountains areas through tonight...mainly
above 11000 feet. Moore

Long term...(wednesday through monday)
issued at 340 am MDT Tuesday may 5 2015 period continues through the extended...

Old upper trough across Colorado pulls away to the northeast on
Wednesday...just as the next trough drops into the Pacific
northwest...picking up shortwave energy off the coast of California...and
sending it inland towards the Great Basin as the West Coast trough
continues to dig southward and close off. Surface low lifts off to
the northeast on Wednesday sending drying westerly flow across much
of the forecast area by Wednesday afternoon. Still enough moisture
Wednesday morning for scattered showers along the Continental Divide
early...and although precipitation waters are dropping off during the
afternoon...there is still sufficient moisture/instability...and
perhaps even some weak forcing as the shortwave dampens out as it
heads towards the 4 corners region. So...with afternoon heating
should see another round of isolated to scattered showers and
thunderstorms...which will move off into the adjacent plains. Convective available potential energy
will be lower...though pockets of up to 700 j/kg will be possible in
the afternoon. Overall...threat for flash flooding on burn scars
will be lower...but not entirely zero as precipitation waters will still be
a little over 1/2 inch across the southeast mts/adjacent
plains...sufficient to produce locally heavy rainfall.
Showers and thunderstorms will diminish during the evening
hours...then a front drops into the southeast plains late Wednesday
night/early Thursday morning.

By Thursday afternoon...winds will swing around from the southeast
across the plains...and will begin the process of advecting higher
dew points back westward. Nam12 shows thunderstorms firing again
across the mountains...though dry southwest flow across the
mountains...through drier air will be moving into the Southwest
Mountains and will limit convection to mainly the northern
areas. Nam12 also shows thunderstorms initiating along the Palmer
and along a northward shifting warm front across the far southeast
plains. Dew points may still be a bit limited initially...but middle
to upper 40s could yield cape values near 1000 j/kg. Assuming
instability is in place...far southeast plains could see an
increasing severe thunderstorm threat Thursday afternoon as increasing
southwest flow overtop east to southeast surface winds north of the
front...will yield deep layer shears of 40 kts. Greatest threat
area looks to be across the easternmost counties (baca and prowers)
for now.

Models diverge with the track of the upper low for Friday and
beyond...with GFS dropping it southward into Southern California by 00z
Sat...then lifting it to the east northeast across central nm and
into southeast Colorado as a tightly wrapped up system by 06z sun. European model (ecmwf) track
is farther north lifting it across southern Utah/northern Arizona Friday
night...then across Colorado on Sat. The southern track advertised by the
GFS would bring the wettest solution for southern Colorado. In
fact...if GFS is correct...Saturday could be an interesting
severe weather set up for southeast Colorado...and cold air coming in with
the system also suggests some snow for the mountains Sat night and
into Sunday. European model (ecmwf)...keeps the focus for heavier precipitation
farther north. Given the spread in the models...and the propensity
for future changes...grids will bring increasing shower and
thunderstorm chances beginning Friday (which could be a day two
severe weather set up for a greater portion of the southeast
plains)...then increasing chances for Saturday and Sunday as the
system moves across the southern or central rockies. Overall...looks
like an active pattern and one worthy of watching
closely...especially for flash flood potential on burn
scars...potential periodic severe thunderstorms across the
plains...and perhaps another round of late season mountain snow. -Kt


Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 340 am MDT Tuesday may 5 2015

Given the continued wet scenario in place across the region over the
next 24 hours...kcos and kpub continue to be forecast to be more
affected than kals. Therefore...look for IFR to at times LIFR
conditions for kcos...kpub and much of the east plains through
tonight...with some improvement possible by 09z. Kals will continue
to see MVFR conditions with intermittent IFR conditions under
heavier showers.


Pub watches/warnings/advisories...
Flash Flood Watch through this afternoon for coz081-084-085.



Short term...Moore
long term...knots

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