456  
FNUS21 KWNS 201611  
FWDDY1  
 
DAY 1 FIRE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1111 AM CDT THU JUL 20 2017  
 
VALID 201700Z - 211200Z  
   
..CRITICAL FIRE WEATHER AREA FOR PARTS OF NORTHERN MONTANA
 
 
A CRITICAL DESIGNATION IS INTRODUCED ACROSS NORTH-CENTRAL MONTANA,  
WHERE ENHANCED WESTERLY WINDS ARE FORECAST TO DEVELOP BEHIND A COLD  
FRONT THIS AFTERNOON AND EVENING. SUSTAINED WESTERLY WINDS AROUND  
20-25 MPH WILL COMBINE WITH RH VALUES BELOW 20% AND VERY DRY FUELS  
TO PROMOTE CRITICAL FIRE-WEATHER CONCERNS. ELSEWHERE ACROSS THE  
NORTHERN ROCKIES REGION, LOCALLY CRITICAL CONDITIONS MAY DEVELOP  
LATER TODAY, BUT CONFIDENCE IN SUFFICIENTLY STRONG WINDS REMAINS TOO  
LOW FOR THE INTRODUCTION OF A CRITICAL AREA.  
 
ADDITIONALLY, AN ISOLATED DRY-THUNDERSTORM AREA IS INTRODUCED ACROSS  
NORTHERN MONTANA. WITH A MID-LEVEL IMPULSE SKIRTING THE REGION (AND  
THE AFOREMENTIONED PASSAGE OF THE COLD FRONT), ISOLATED STORMS MAY  
DEVELOP LATE TODAY. WEAK MID-LEVEL BUOYANCY, A DEEP/DRY BOUNDARY  
LAYER, AND QUICK STORM MOTIONS WILL SUPPORT A POTENTIAL FOR A FEW  
DRY LIGHTNING STRIKES.  
 
..PICCA.. 07/20/2017  
   
PREV DISCUSSION
 
/ISSUED 0158 AM CDT THU JUL 20 2017/  
   
..SYNOPSIS
 
 
UPPER RIDGING WILL REMAIN PROMINENT ACROSS THE CENTRAL/SOUTHERN  
PLAINS TODAY, WHILE AN UPPER TROUGH MOVES SLOWLY NORTHEASTWARD FROM  
BC AND THE PACIFIC NORTHWEST OVER THE NORTHERN ROCKIES AND ADJACENT  
CANADIAN PROVINCES. ENHANCED MID-LEVEL WINDS ATTENDANT TO THIS  
TROUGH SHOULD ELEVATE FIRE WEATHER CONCERNS THIS AFTERNOON AND  
EVENING ACROSS PARTS OF THE INTERIOR PACIFIC NORTHWEST, NORTHERN  
GREAT BASIN/ROCKIES, AND NORTHERN HIGH PLAINS.  
   
..PORTIONS OF THE INTERIOR PACIFIC NORTHWEST
 
 
BEHIND A SURFACE COLD FRONT, TEMPERATURES WILL BE SLIGHTLY COOLER  
THAN YESTERDAY ACROSS INTERIOR PORTIONS OF THE PACIFIC NORTHWEST.  
REGARDLESS, STRONG/GUSTY WEST-SOUTHWESTERLY WINDS AROUND 15-20 MPH  
WILL LIKELY DEVELOP THIS AFTERNOON AS DOWNSLOPE TRAJECTORIES ACT TO  
WARM/DRY THE LOW LEVELS. RH VALUES WILL BECOME LOWERED INTO  
GENERALLY THE 20-25% RANGE, SUPPORTING THE ONGOING ELEVATED FIRE  
WEATHER DELINEATION.  
 
...PORTIONS OF THE NORTHERN GREAT BASIN/ROCKIES INTO THE NORTHERN  
HIGH PLAINS...  
A CORRIDOR OF ENHANCED MID-LEVEL SOUTHWESTERLY WINDS WILL REMAIN  
OVER PARTS OF THE NORTHERN GREAT BASIN/ROCKIES INTO THE NORTHERN  
HIGH PLAINS. AS DIURNAL MIXING OF THE BOUNDARY LAYER OCCURS, THESE  
MID-LEVEL WINDS WILL REACH THE SURFACE AND PROMOTE STRONG SUSTAINED  
WINDS OF 15-20 MPH. RH VALUES WILL ALSO LIKELY BECOME LOWERED INTO  
THE 10-20% RANGE FROM THE SNAKE RIVER VALLEY OF ID AND VICINITY  
NORTHEASTWARD INTO PARTS OF THE NORTHERN ROCKIES/HIGH PLAINS. DRY  
FUELS WILL EXIST ACROSS A MAJORITY OF THESE REGIONS, SUPPORTING AN  
ELEVATED FIRE WEATHER THREAT. LOCALLY CRITICAL CONDITIONS MAY BE  
REALIZED ACROSS A SUBSET OF THE SNAKE RIVER VALLEY IN ID, WHERE  
SUSTAINED WINDS MAY EXCEED 20 MPH ON A BRIEF/SPOTTY BASIS.  
   
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
 
 

 
 
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