Area Forecast Discussion
Issued by NWS North Platte, NE
FXUS63 KLBF 180917
Area Forecast Discussion
National Weather Service North Platte NE
417 AM CDT Tue Apr 18 2017
.SHORT TERM...(Today and tonight)
Issued at 416 AM CDT Tue Apr 18 2017
Radar shows clusters of showers and thunderstorms over north central
NEB moving eastward at about 40-50 mph. After midnight there were a
few strong storms that warranted Special Weather Statements.
Otherwise, the threat for storms reaching severe levels after 4 AM
CDT is very low. The primary concerns with these storms are gusty
winds, brief heavy rain, and small hail. Latest satellite imagery
shows some low-level stratus into southwest NEB west of the
convective activity with ceilings 10-20 kft.
The main sensible weather concerns in the short term period revolve
around lingering convective activity early this morning then
potential for showers/thunderstorms tonight. Forecast challenges
include precipitation timing tonight and the overall likelihood for
strong to severe thunderstorms.
A vigorous short wave trough is evident in the latest water vapor
imagery over central SD and south central ND. This positive PV
anomaly will move into the Upper Mississippi Valley by mid morning.
Dry conditions are expected the remainder of the morning, once the
convective activity exits, through the afternoon. Another warm day
on tap with highs forecast 10-14 degrees above normal in the lower
to mid 70s.
Attention then turns to the next mid-level disturbance where another
positive PV anomaly will track from the Southwest US late this
afternoon quickly east into the Central High Plains by late evening.
Moisture will once again be transported into western and north
central NEB late today with increasing instability developing over
the local forecast area this evening and overnight. Surface dew
points increasing into the lower 50s by this evening across the
southern-third of the local forecast area. Meanwhile, the shortwave
trough will provide large scale forcing tonight and help increase
mid-level lapse rates (700-500 hPa) tonight around 7-8.75 C/km.
This environment combined with deep-layer shear (e.g., BUFKIT
sounding progs effective shear ~40-45 kts at KLBF) support the
potential for strong to severe thunderstorms tonight. Also present
will be potential for brief heavy rain considering moisture in the
column and precipitable water values approaching 200% of normal in
portions of the area. A little more confidence in this convective
scenario overnight with likely PoPs present across portions of the
area after midnight tonight.
.LONG TERM...(Wednesday through Monday)
Issued at 315 AM CDT Tue Apr 18 2017
Active pattern will continue the next several days. GFS Ensemble
mean indicates two closed lows will move across the region. The
first will move eastward across South Dakota during the Day
Wednesday. Mid level warm air advection will be underway
Wednesday morning, with showers likely across northern Nebraska.
Enough instability present to mention isolated thunder through at
least early afternoon. Thursday should be mainly dry as shortwave
ridging aloft briefly builds across the central plains ahead of
the next storm system. This one is currently forecasted to move
across Kansas, with the H700mb low center in central or north
central Kansas early Friday evening. Deformation band of showers
is likely across southwest Nebraska much of Friday into Friday
evening, with lesser chances farther north. Saturday into Sunday
ridging aloft should take control once again, with mainly dry
conditions. By Monday the next system will move across the
northern plains, with a slight chance for showers as far south as
Temperature wise expect highs in the mid 50s to mid 60s for most
of the period, with highs possibly near 70 across parts of the
area Sunday into Monday. Lows will be in the mid 30s to mid 40s.
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1223 AM CDT Tue Apr 18 2017
Some light rain showers and isolated thunderstorms from KVTN to
north of KOGA will continue to move east through the early
morning. Carried VCTS at KVTN early this morning based on radar
trends and hi-res guidance. Generally VFR cigs but some areas of
MVFR exist. Winds to become southwest and then west through the
early morning hours with winds becoming northwest around