Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Goodland Kansas
540 am MDT Wednesday Aug 5 2015
Short term...(today through Friday night)
issued at 312 am MDT Wednesday Aug 5 2015
As of 4 am CDT...3 am MDT...skies across the tri-state region ranged
from clear to overcast as widespread fog and stratus develops.
Temperatures are in the upper 50s to middle 60s. Winds are light and
variable. Latest WSR-88D radar imagery indicates all storms remain
east of the forecast area over central Kansas. Latest satellite fog
imagery highlights a band of fog and stratus stretching from Holyoke
and Wray Colorado...clipping southwest Nebraska and into northwest
Kansas. At the surface...a trough of low pressure extended from the
Colorado Front Range...across the tri-state region and into central
Nebraska. Aloft...a departing shortwave trough is located over
northwest Kansas with an area of drier air and subsidence moving
Main forecast concern today is the dense fog expected this morning.
As mentioned above...widespread dense fog is developing and this
trend should continue through the early morning hours. As
temperatures warm after sunrise...fog should gradually lift and
dissipate by late morning. It was tough to determine how much of an
impact residual fog/stratus would have on high temperatures today.
Did lower temperatures over the northeastern forecast area due to
anticipated lingering stratus. With shortwave ridging overhead this
evening...do not anticipate a substantial chance for precipitation.
However...it is possible a few storms are able to develop along the
Front Range and slide into northeast Colorado and extreme southwest
Nebraska. Did include a slight chance for storms but do not feel
this potential activity would amount to anything.
Another potential round of fog is possible with a lingering frontal
boundary still in place Thursday morning. Input patchy fog into the
forecast. By afternoon...a weak shortwave trough should slide
through. However...dry air aloft and lowered instability do not
suggest a favorable environment for thunderstorms. As with last
night's forecast...do not feel confident or impressed with storm
chances Thursday. Decided to eliminate thunderstorm mention from
this forecast package.
On Saturday...another round of thunderstorms appears likely with a
substantial shortwave trough and significant increase in moisture
anticipated. With the moisture return...instability increases and
precipitable water readings approach/exceed 2 Standard deviations
above normal. In addition...an upper level wind maximum with the
shortwave and southeast surface winds will allow for a significant
increase in 0-6 km bulk shear to near 50 kts...similar to what
occurred yesterday. Therefore...increased thunderstorm chances and
mentioned severe weather and heavy rains possible in the hazardous
weather outlook. Saturday will need to be monitored in future
forecast runs as the potential exists for another severe weather
Long term...(saturday through tuesday)
issued at 216 am MDT Wednesday Aug 5 2015
An upper level ridge will dominate the weather pattern for the tri
state area in the long term forecast period...which will bring
widespread dry weather and plenty of sunshine. However...embedded
shortwave troughs in the upper and middle levels will bring chances for
showers and thunderstorms each day through the forecast period.
Model forecast soundings from European model (ecmwf) and GFS indicate plenty of moist
air in the profile during the period between 1 and 2 inches for
locations across the High Plains...so heavy rain in developing
thunderstorms looks to be possible. Cape values at and above 1000
j/kg will support the development of stronger thunderstorms. However
shearing winds looks to be lacking at the moment due to the absence
of any potential jet energy near the forecast area. The upper level
ridge will remain somewhat stationary Saturday and Sunday before
retrograding and increasing in amplitude on Monday and Tuesday.
Southerly winds at the surface through the period will advect plenty
of moist air into the High Plains with dew points expected in the
upper 50s to lower 60s. High temperatures will be near normal in
the upper 80s and lower 90s on Saturday and Sunday...which in
combination with higher dew points will bring heat indexes up into
the middle 90s at times. A weak surface cold front will push through
the High Plains on Monday...which will bring slightly cooler
temperatures in the middle to upper 80s for Monday and Tuesday...which
is only a bit cooler than normal for this time of year.
Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 540 am MDT Wednesday Aug 5 2015
Fog/stratus should remain problematic this morning at both taf
sites. Both taf sites are VFR as of issuance time yet MVFR to LIFR
conditions remain nearby. Dense fog remains within 20 miles of
kgld while stratus with MVFR ceilings is within 20 miles of kmck.
Fog/stratus will burn off by late morning. Another round of
fog/stratus is possible early tomorrow morning with the stalled
front and high boundary layer moisture still in place. Do not
anticipate any afternoon thunderstorms today with dry air aloft
and shortwave ridging overhead.
Kansas...dense fog advisory until 10 am MDT /11 am CDT/ this morning for
Colorado...dense fog advisory until 10 am MDT this morning for coz090.
NE...dense fog advisory until 10 am MDT /11 am CDT/ this morning for