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Area forecast discussion 
National Weather Service Goodland Kansas
852 PM MDT Friday Jul 25 2014

issued at 846 PM MDT Friday Jul 25 2014

Radar trends over the last hour have shown an increase in
intensity of the line of storms moving eastward. Looking at RUC
soundings for Tribune the best elevated instability is above
700mb...with a bulls eye of near 1500j/kg of cape just west of the
Kansas/Colorado line in eastern Cheyenne County. This instability drifts
south-southeast over the next couple of hours before dissipating.
Meanwhile the elevated cape will linger until around midnight then
end as the environment stabilizes.


Short term...(this afternoon through saturday)
issued at 112 PM MDT Friday Jul 25 2014

Early afternoon WV imagery and rap upper level analysis show broad
ridge still in place from the desert SW across the Southern
Plains...with a plume of middle-upper level moisture and weak vorticity
rotating around the northern periphery of this ridge across the
central rockies into the High Plains. A closed low is moving across
southern Canada with some weak reflection of this extending further
south into the northern plains. At the surface a weak cold front has
stalled over the southern part of our County Warning Area...with favorable July
solar angle supporting good radiational warming this afternoon as
highs have still reached the middle to upper 90s over much of the County Warning Area
(a little cooler towards the nw).

Stalled front in the south combined with elevated terrain in
Colorado should help initiate thunderstorms (which have already
developed along front range). High local/level of free convection over our County Warning Area should keep
thunderstorm activity elevated and with increasing instability and
dcape would support potential for downbursts. If updrafts are strong
enough...maybe large hail would be possible this
afternoon/evening...however with very warm low-middle levels above
shallow frontal inversion conditions are more in line with a wind
threat. Guidance continues to show better coverage over
County Warning Area...however despite good surface-bl moisture along frontal zone
air mass itself is fairly dry and coverage is a question. Best
forcing would actually be later in the evening as shortwave (along
with possible outflow from possible mesoscale convective system in the north) moves into the
County Warning Area. At this point I was comfortable keeping coverage isolated and
delayed exit until after 06z. Will need to monitor trends as western
locations could see slightly better coverage before sunset.

Deepening on evolution of outflow (as indicated by nam) or weak
frontal passage Saturday temperatures could be tricky once again as heights
and pattern aloft would generally support good daytime heating and a
recovery of the air mass in place. I kept temperatures similar to today
with above normal values in the 90s (around 100f in the east). High
based thunderstorms may develop again Saturday afternoon along
frontal zone in the south...however confidence is low on earlier
initiation over our County Warning Area...with flow more supportive of upstream
development in Colorado.

Long term...(saturday night through friday)
issued at 220 PM MDT Friday Jul 25 2014

Upper flow transitions from zonal to northwesterly in the sun-Monday
time frame...which then continues through the rest of the week.
At the surface...a reinforcing shot of cooler air drops down Saturday
night which pushes the surface front well south of the forecast
area. As a result...much of the precipitation potential early on
will be south and west of the County Warning Area. The best window for thunderstorms
in the extended period will be Tuesday night-Wednesday night when the ec/GFS
both generate an extensive area of precipitation which moves
southeast across the region as a short wave trough drops through
the flow.

The presence of a Canadian air mass which dominates the entire week
will provide relief from the recent stretch of hot weather. 850 mb
temperatures are forecast to remain in the 22-25c range through
next weekend...which translates to low-middle 80s for highs. The
coolest day will be Wednesday given the likely presence of clouds
and scattered showers and thunderstorms. Depending on cloud cover
there is potential for some areas to remain in the upper 70s Wednesday.


Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 525 PM MDT Friday Jul 25 2014

VFR conditions forecast for the 0z tafs. Winds will become light
and variable tonight then strengthen from the north Saturday

Current radar shows a line of storms over eastern Colorado slowly
moving west. Near term models disagree how far east the storms
will make it early this evening. Soundings look fairly stable for
elevated convection this am wondering how far east
the current line will move...specifically for kgld. For now will
keep T-storm mention out of the forecast for kgld. However if
storms do move near the site will most likely be during the 3-4z
time frame.


Gld watches/warnings/advisories...


short term...Dr
long term...dlf

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