843  
FXUS65 KCYS 160830  
AFDCYS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHEYENNE WY  
230 AM MDT TUE JUL 16 2019  
   
SHORT TERM
 
(TODAY THROUGH THURSDAY NIGHT)  
ISSUED AT 230 AM MDT TUE JUL 16 2019  
 
FORECAST CONCERNS DEAL WITH SEVERE THUNDERSTORMS TODAY...FOLLOWED  
BY FIRE WEATHER CONCERNS THURSDAY INTO FRIDAY.  
 
CURRENTLY...FRONTAL BOUNDARY LAYS ALONG A LINE FROM JUST NORTH OF  
SIDNEY TO JUST SOUTH OF RAWLINS THIS MORNING. DEWPOINTS IN THE  
UPPER 50S NORTH OF THIS FRONT ACROSS THE PANHANDLE WITH MID 50S  
ACROSS PARTS OF SOUTHEAST WYOMING. WATER VAPOR IMAGERY SHOWING THE  
MOISTURE PLUME THAT HAS BEEN FUELING AFTERNOON THUNDERSTORMS...  
STARTING TO SHIFT EASTWARD INTO CENTRAL NEBRASKA AND WESTERN  
KANSAS THIS MORNING WITH MUCH DRIER AIR MOVING INTO WESTERN  
COLORADO AND SOUTH CENTRAL WYOMING.  
 
FOR TODAY...FRONTAL BOUNDARY BEGINS TO SHIFT EASTWARD AS A DRYLINE THROUGH  
THE DAY AS DRIER AIR MOVES INTO CARBON AND ALBANY COUNTIES. BY  
21Z...FRONT LOOKS TO BE CLEAR OF THE PANHANDLE WITH 850MB HUMIDITY  
IN THE PANHANDLE DOWN NEAR 15 PERCENT ON THE GFS. LOOKS LIKE OUR  
NORTHERN CWA WILL BE THE FOCUS FOR SEVERE THUNDERSTORMS TODAY.  
HRRR AND HIRESNMM BOTH SHOW STORMS DEVELOPING ALONG THE  
DRYLINE/FRONT AFTER 18Z...SHIFTING EAST THROUGH THE PANHANDLE BY  
00Z. AFTERNOON MUCAPES NEAR 3000 J/KG WITH SFC TO 6KM SHEAR AROUND  
40KTS. LARGE HAIL AND STRONG DOWNBURST WINDS LIKELY ALONG AND  
NORTH/EAST OF A LINE FROM DOUGLAS TO TORRINGTON TO KIMBALL TODAY.  
THINKING AFTER 00Z...MOST OF THE STORMS WILL HAVE MOVED INTO  
CENTRAL NEBRASKA AND CENTRAL NORTH DAKOTA.  
 
NOT TOO SURE ABOUT WEDNESDAY IN TERMS OF THUNDERSTORMS AS THAT  
DRIER AIR WILL LIKELY BE FIRMLY IN PLACE ACROSS THE CWA. BUT SPC  
HAS A MARGINAL RISK AREA FOR THE NORTHERN PANHANDLE BACK INTO  
CONVERSE/NIOBRARA COUNTIES WEDNESDAY AFTERNOON. DID UNDERCUT  
GUIDANCE ON POPS THOUGH.  
 
WINDY CONDITIONS FOR THURSDAY AS GFS 700MB WINDS CLOSE TO 40KTS  
ACROSS PARTS OF SOUTHEAST WYOMING. WE COULD MIX WINDS DOWN FROM  
500MBS THURSDAY...WHICH SHOWS ROUGHLY 40-45KTS AT THAT LEVEL ON  
GFS SOUNDINGS OVER RAWLINS.  
   
LONG TERM
 
(FRIDAY THROUGH MONDAY)  
ISSUED AT 230 AM MDT TUE JUL 16 2019  
 
ONE MORE QUITE WARM AND DRY DAY EXPECTED ACROSS THE CWA FRIDAY  
THOUGH A MODEST COOL FRONT MAY SAG SOUTH OVER THE PLAINS DURING  
THE DAY. SATURDAY THROUGH MONDAY SHOULD SEE COOLER CONDITIONS  
ALONG WITH INCREASING CHANCES FOR SHOWERS AND TSTMS AS SOME  
SUBTROPICAL MOISTURE ROUNDS THE WESTERN PERIPHERY OF AN UPPER HIGH  
OVER THE SOUTHERN ROCKYS AND OVER THE REGION. SUNDAY LOOKING TO BE  
THE COOLEST DAY AS THE CWA GETS CLIPPED BY A SFC HIGH THAT MOVES  
ALONG THE INTERNATIONAL BORDER.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 230 AM MDT TUE JUL 16 2019  
 
VFR EXPECTED TO PREDOMINATE THROUGH THE PERIOD. SCTD SHOWERS AND  
TSTMS ONCE AGAIN DEVELOPING OVER SE WY EARLY THIS AFTERNOON AND  
MOVING OVER THE PANHANDLE LATE AFTN/EARLY EVENING WITH BRIEF GUSTY  
AND ERRATIC WINDS AND MAINLY MVFR VSBYS ASSOCIATED WITH STRONGER  
CELLS.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 230 AM MDT TUE JUL 16 2019  
 
ONE LAST DAY OF SHOWERS AND THUNDERSTORMS TODAY...MAINLY EAST OF  
THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE. THEN CONDITIONS  
TURN DRIER AND WINDIER. COULD BE A FEW HIGH BASED STORMS WEDNESDAY  
AFTERNOON...BUT OVERALL...DRIER CONDITIONS EXPECTED. VERY DRY  
CONDITIONS BEGIN ACROSS CARBON COUNTY STARTING THIS  
AFTERNOON...SPREADING EAST ON WEDNESDAY AND THURSDAY. AFTERNOON  
HUMIDITY EXPECTED TO FALL INTO THE LOW TEENS EACH DAY WITH POOR  
OVERNIGHT RECOVERIES. LATE MORNING AND AFTERNOON WESTERLY WINDS  
GUSTING CLOSE TO 40 MPH WILL COMBINE WITH THE DRY AIRMASS TO  
CREATE ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS.  
FORTUNATELY...FUELS ARE STILL REPORTED AS NOT RECEPTIVE TO RAPID  
FIRE SPREAD AT THIS TIME. THE EXCEPTION IS FWZ 310...WHICH WILL  
LIKELY NEED A FIRE WEATHER WATCH FOR THURSDAY.  
 

 
   
CYS WATCHES/WARNINGS/ADVISORIES
 
 
WY...NONE.  
NE...NONE.  

 
 

 
 
SHORT TERM...GCC  
LONG TERM...RE  
AVIATION...RE  
FIRE WEATHER...GCC  
 
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