Red Flag Warning issued April 19 at 11:42AM MDT until April 20 at 8:00PM MDT by NWS Rapid City SD

Details

...3 DAYS OF NEAR-CRITICAL TO CRITICAL FIRE WEATHER CONDITIONS
EXPECTED ACROSS NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA
MONDAY THROUGH WEDNESDAY...

.High pressure building into the region will support a strong
warming and drying trend across northeastern Wyoming and western
South Dakota today through Wednesday. Daily afternoon relative
humidity values will drop into the 8 to 20 percent range by Monday
and stay there each afternoon through Wednesday, while
temperatures gradually warm into the 80s to near 90. Winds will
be more marginal and somewhat of a limiting factor at times for
meeting formal critical fire weather thresholds, but gusts of at
least 25 MPH will likely overlap with these dry humidity values in
some areas each day, with much stronger winds regionwide
Wednesday. The combination of dry fuels, low relative humidities,
gusty winds, and hot temperatures will support widespread near-
critical to critical fire weather conditions, with multiple Red
Flag Warnings possible over the period. The first warning has been
issued for portions of northeastern Wyoming and the southwestern
and south-central South Dakota plains for Monday.

The National Weather Service in Rapid City has issued a Red Flag
Warning for gusty winds and low relative humidity, which is in
effect from 11 AM MDT /noon CDT/ to 8 PM MDT /9 PM CDT/ Monday.

* AFFECTED AREA...Fire Weather Zones 315 Southern Campbell, 317
Weston County Plains, 321 Southern Black Hills, 322 Fall River
County Area, 325 Custer County Plains, 326 Pine Ridge Area,
332 Badlands Area, 333 Bennett County Area, 334 Mellette and
Todd Counties, and 335 Tripp County.

* WINDS...West 10 to 20 MPH with gusts up to 30 MPH.

* RELATIVE HUMIDITY...As low as 9 percent.

* IMPACTS...The combination of dry fuels, low relative humidities,
gusty winds, and hot temperatures will produce critical fire
weather conditions. New fires could spread rapidly.