Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 200124 AAB

Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
824 PM CDT Sat May 19 2018

Issued at 823 PM CDT Sat May 19 2018

Updated to increase and decrease some rain chances.


.SHORT TERM...(This evening through Sunday)
Issued at 330 PM CDT Sat May 19 2018

The primary forecast challenges through Sunday afternoon revolve
around the upper low centered over the Sandhills and the cold front
dropping through the state. Rain showers (some heavy) have affected
the forecast area for the past couple days with widespread 3-4"
totals as of Saturday early afternoon. The areal Flood Watch
continues through 00z for portions of SW Neb and the river Flood
Warning for the N.Platte River continues through Tue night.

This evening and tonight... Near term solutions (HRRR/RAP/HREF) have
been portraying this system fairly well, and continue the
deformation band into the early evening across the Sandhills. As the
upper low slowly treks through the area, some regeneration of
showers is expected SW Neb (and some signs have already begun
showing up on satellite and radar as of 20z). RAP mesoanalysis
indicates the continuous moisture flow from the southern Plains and
near-record PWAT. Broad isentropic upglide shown at multiple theta
levels as well as mid-level fgen will maintain precip potential.
Maintained QPF through 06z at 1/4 to 1/2", mainly across the
Sandhills. Removed thunder mention as CAPE and effective shear are
essentially non-existent and sfc temps struggling to reach the 50s.
Temp-wise, cooled overnight lows slightly but kept near the top end
of guidance due to thick cloud cover. Forecast lows range from upper
30s panhandle to mid 40s north central. No frost headline expected
due to ongoing precip and low confidence in reaching lower/mid 30s.
Gusty north winds also wane through the evening as the surface
pressure gradient relaxes and H85 flow backs off.

Sunday... Few remaining showers possible for central Neb due to the
vicinity of the low/enhanced forcing, but moisture isn`t nearly what
it was the past couple days. Isentropic upglide weakens and
transitions to downglide by the afternoon. Overall, looking at
partly to mostly cloudy skies and continued cool conditions. Went
with a general MAV/MET/ECS blend for max temps, resulting in lower
60s (and slightly cooler north central), which is about ten degrees
below normal. Seems reasonable given aforementioned cloud cover,
north winds, and H85 temps under 10C.

.LONG TERM...(Sunday night through Saturday)
Issued at 330 PM CDT Sat May 19 2018

The next chance of thunderstorms is Monday evening. Both the NAM and
GFS indicate favorable shear and instability for some severe weather
potential. SPC has not outlooked wrn or ncntl Neb for severe weather
but Bufkit, the MET, MAV and ECS guidance, the SREF and the CIPS
analogs suggest some level of potential. SPC will review the severe
weather potential for Monday, tonight.

Another severe thunderstorm opportunity develops Wednesday
associated with an upper level low lifting through the nrn Rockies.
This should produce favorable winds aloft and moisture will be in
place with dew points in the mid 50s to lower 60s. Note that some
sort of thunderstorm chance is in the forecast Monday through Friday
and this is consistent with return moisture, strong daytime heating
and the potential for nocturnal forcing associated with a low level
jet. Monday and Wednesday would appear to be the best chances. This
is based on a local severe weather ensemble procedure suggesting
Monday as "likely" and Wednesday and Thursday as "possible".

Forecast highs rise into the 70s Monday and 80s Tuesday and beyond.
The GFS and the model consensus would suggest drier air moves in
Thursday. This is the result of a Pacific cold front.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 648 PM CDT Sat May 19 2018

Widespread light rain will continue to diminish ian area and
intensity over western Nebraska tonight. Light north winds will
continue over northern Nebraska qhile stronger northerly flow will
continue over southern Nebraska. Mvfr conditions with occasional
ifr ceilings are possible over southern Nebraska through Sunday
morning while vfr cigs are expected over the north.




SHORT TERM...Snively
AVIATION...Power is the U.S. government's official web portal to all federal, state and local government web resources and services.