895 
FXUS63 KUNR 041632
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1032 AM MDT Sun Apr 4 2021

.DISCUSSION...(Today Through Saturday)
Issued at 252 AM MDT Sun Apr 4 2021

Water vapor places flat upper level ridge over the plains. High
clouds increasing upstream...which will spread across the forecast
area today. Low level thermal temperatures support near record
highs. With surface trof moving through western South Dakota winds
will highly dependent on deep mixing. 

Cold front slides through the area Monday. South central South
Dakota will see another day in the low 80s...with noticeably 
cooler conditions elsewhere. Attention turns to system moving 
through Tuesday/Tuesday night, with widespread precipitation. 
Deterministic models and ensemble means continue with southward 
shift in track of upper low...with best lift focused over southern
portions of forecast area. Northern edge of precipitation will be
fighting with dry north-northeast low level flow. High 
probability of 1/4" or more of QPF Tuesday/Tuesday night...mainly 
along and south of I-90. Thermal profiles support snow in the 
Black Hills, with rain/snow mix onto the plains. Several inches of
snow accumulation likely for the Black Hills, with plains snow 
mainly limited to grassy/elevated surfaces. 

For the remainder of the week, temperatures will settle in near
seasonal averages. A few passing impulses may bring some light
shower activity. 

&&

.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1032 AM MDT Sun Apr 4 2021

VFR conditions will continue through the forecast period.

&&

.FIRE WEATHER...
Issued at 252 AM MDT Sun Apr 4 2021

Elevated fire weather conditions are expected today and tomorrow.
Dry conditions continue today with increasing cloud cover. 
Afternoon relative humidity will drop to 10-15%. Deep mixing will 
bring some locally gusty winds. With the shorter duration and 
localized nature of the stronger winds, will not issues any fire 
weather headlines at this time. 

Cold front moves through Monday, with gusty north winds. Minimum
will bottom out around 20 percent Monday afternoon...slightly 
higher behind the front. 

A storm system will bring wetting rains to most areas along and
south of Interstate 90...with very little precipitation in far
northwest South Dakota. For the Black Hills, several inches of
snow can be expected. A rain/snow mix is possible on the plains. 

Temperatures will settle in near average for the end of the week
with afternoon humidity ranging from 25 to 35 percent.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION...7
AVIATION...Johnson
FIRE WEATHER...7