Area Forecast Discussion
Issued by NWS North Platte, NE
FXUS63 KLBF 172354 AAA
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
654 PM CDT Mon Apr 17 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 336 PM CDT Mon Apr 17 2017
An upper level trough will move across the Northern and Central
Plains tonight. Steep mid level lapse rates 7.5-8.0 c/km and
sbcapes 500-800 j/kg will combine with 0-3 km shear from 40 to 45
kts. This will be supportive of marginally severe hail and wind
gusts west of valentine through Ogallala. Coverage will likely be
isolated at best, with rapid refresh and RAP models showing very
little development into the northwest.
The best forcing aloft will be across South Dakota. However, with
precipitable water values around three quarter of an inch early
this evening increase to over one inch across the eastern
forecast area overnight. IF any organized areas of storms do
develop, brief heavy rain is likely. Thunderstorms chances are
from 20 percent across the southwest, and 30 to 40 percent across
north central and central Nebraska. The trailing end of any
showers or storms should exit the eastern zones by daybreak. A
weak cold front will also sweep thorugh the area overnight.
.LONG TERM...(Tuesday night through Monday)
Issued at 336 PM CDT Mon Apr 17 2017
On Tuesday, partly cloudy and mild with highs ranging in the 70s.
Southwesterly flow will be across the western conus as nearly
zonal flow exists across the Central Plains. A disturbance will
exit California and move into the Great Basin on Tuesday. By
Tuesday evening, this upper trough will approach the area,
providing another chance for showers and thunderstorms. A warm
front across northern Kansas will remain nearly stationary.
Increased instability and 0-3km shear from 30-45 kts sufficient
for strong storms across most of western Nebraska overnight. The
thunderstorms are expected to be elevated, so marginally severe
hail will be the most likely hazard. Some storms may also contain
brief heavy rain.
As the upper trough crosses the area on Wednesday, showers and a
few thunderstorms remain likely across north central Nebraska.
Chances decrease or end across southwest Nebraska. Models differ
on amount of cold air advection behind the front. Current forecast
highs remain near the previous, although the GFS model would
support warmer highs in the lower and mid 70s across southwest
Nebraska. Northwest winds to increase to 10 to 25 mph Wednesday
An upper trough will dig across the Pacific Northwest into the
Great Basin on Thursday, and close off over Colorado and western
Kansas on Friday afternoon. This southeastward tracking system
will provide better chances for showers to the southwestern half
of the forecast area Thursday night through Friday night, while
most of the northeast should remain dry. Aside from a slight
chance for morning showers southeast on Saturday morning, the
remainder of the weekend looks dry. A mid level disturbance Monday
for a slight chance of showers.
Forecast highs on Wednesday contrast from mid and upper 50s
north, to the mid 60s to lower 70s south. Highs in the mid 60s
Thursday, cool to the mid and upper 50s by Friday and Saturday,
influenced by the upper trough and Canadian high pressure across
the region. By Sunday, upper ridging builds back into the the
region to bring warmer highs in the mid and upper 60s.
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 649 PM CDT Mon Apr 17 2017
Mid and high clouds over most of western Nebraska tonight. Some
MVFR cigs will move into southwest Nebraska over night. Strong
southerly flow will continue through the early morning. Some
isolated showers or virga will continue to move to the east over
the Nebraska Sandhills through midnight. Winds will shift to the
west and then northwest through Tuesday morning. With uncertainty
of showers have only carried vcsh.