000
FXUS63 KLBF 190045
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
745 PM CDT Mon Mar 18 2019

.SHORT TERM...(This evening through Tuesday night)
Issued at 316 PM CDT Mon Mar 18 2019

The RAP and GFS indicate a convectively enhanced area of snow
developing tonight across ncntl Nebraska. This is about 50 miles
north of the previous forecast. The rain changing to snow forecast
tonight uses a blend of the RAP, HRRR, HREF, model consensus and the
previous forecast for 1 to 2 inches of snow with 0.25-0.33 inches of
total liquid. Since the ground is still frozen across ncntl
Nebraska, this precip will produce additional runoff and overland
flooding across the region Tuesday and Wednesday. The severity of
the flooding from tonight`s rain and snow appears low given the
total liquid is generally around 1/4 inch.

Note that the HRRR, RAP and ECM show convectively induced bulls-eyes
of around 1/2 inch of QPF across ncntl Nebraska which could be
interpreted as periods of heavy rain or heavy snow. The RAP and HRRR
visibility products indicate these are brief so, unless the upper
level support stalls across ncntl Nebraska, the risk of heavy snow
or rain would appear low.

The temperature forecast tonight and Tuesday uses the consensus
model solution. The guidance blend plus bias correction is in place
Tuesday night. This strategy tries to keep temperatures warmer
tonight and cooler Tuesday than the guidance blend. The guidance
blend plus bias correction lowers temperatures Tuesday night.

.LONG TERM...(Wednesday through Monday)
Issued at 316 PM CDT Mon Mar 18 2019

The models are in excellent agreement for a major warming trend
Wednesday through Sunday with temperatures at the h850mb level
rising to between 5C and 10C. Sfc temperatures should rise into the
40s, 50s and 60s with lows in the 20s, 30s and lower 40s. This will
likely result in a period temperatures above freezing both day and
night and a partial to complete spring thaw in some areas of western
and north central Nebraska.

The upper level support for the warming trend is in the form of a
blocking upper level ridge centered over the Great Plains and an
approaching long wave trof moving through srn California and the
desert Southwest. Ultimately the long wave trof will move east and
draw heavy moisture into wrn and ncntl Nebraska with showers
possible beginning as early as Thursday night.

Rain chances continue Friday through Sunday with a slow moving upper
low drifting through the cntl Plains but the models, despite the
very high moisture across Nebraska, focus the best rainfall across
the srn Plains. We will be watching the models this week to see if
there is a northward trend in the Srn Plains rainfall. The flood
potential next weekend revolves around predicting if the heating
this week will be sufficient to remove most or all of the frost from
the ground before rain arrives. The area of concern for flooding is
generally along and north of highway 2.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 742 PM CDT Mon Mar 18 2019

A weather system is tracking southeast toward the area. This will
bring the possibility of scattered precipitation and lower
ceilings. It appears that the higher chance for MVFR or local IFR
conditions will remain across northern Nebraska late tonight into
Tuesday. Winds will become north around 10 kt with gust to 20 kt
Tuesday.

&&

.HYDROLOGY...
Issued at 316 PM CDT Mon Mar 18 2019

After consultation with our key partners in Custer County we`ve
decided to cancel the Flood Advisory for the northern and eastern
portions of the county.  Rivers across the county have returned to
near normal levels while areas that are/were impacted by the
flooding have been barricaded.  The Flood Advisory for Holt County
and portions of north central Nebraska was extended through
Wednesday morning.  Local emergency management continues to report
widespread flooding and highway closures due to ongoing flooding.
The Flood Warning for the Elkhorn River near Ewing remains in
effect.  The latest river forecast shows levels at or above minor
flood stage through at least Tuesday morning.  Given the prospects
of additional light precipitation overnight and the continued
runoff, we felt that additional rises will be possible, thus the
warning was extended until mid-day Wednesday.  Temperatures will
warm once again mid and late week, but an additional storm system is
looking more likely for Friday and next weekend which potentially
could produce a long period of rainfall across north central
Nebraska.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Taylor
HYDROLOGY...Jacobs