428  
FXUS65 KGJT 210106  
AFDGJT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
706 PM MDT FRI OCT 20 2017  
   
UPDATE
 
 
ISSUED AT 702 PM MDT FRI OCT 20 2017  
 
WINDS CONTINUE TO DECREASE ACROSS THE AREA THIS EVENING WITH THE  
LOSS OF DAYTIME HEATING AND DEEPER MIXING. PEAK GUSTS GENERALLY  
UNDER 30 MPH IN MOST AREAS, ALTHOUGH PASSING SHOWERS AND  
APPROACHING COLD FRONT MAY TICK WINDS BACK UP TO NEAR 40 MPH LATER  
THIS EVENING. EVEN WITH THE POTENTIAL UPTICK IN WIND GUSTS, SPEEDS  
WILL STILL BE UNDER ADVISORY CRITERIA. SO DROPPED THE WIND  
ADVISORY AN HOUR EARLY. NEW GRIDDED FORECASTS WILL BE OUT SHORTLY.  
 

 
   
SHORT TERM
 
(TONIGHT THROUGH SATURDAY NIGHT)  
ISSUED AT 342 PM MDT FRI OCT 20 2017  
 
BREEZY TO WINDY CONDITIONS WILL CONTINUE THROUGH THIS EVENING  
UNDER A PRE-FRONTAL SOUTHWEST FLOW. SOME GUSTS HAVE ALREADY  
EXCEEDED 45 MPH IN NORTHWEST COLORADO WITH A GUST OF 60 MPH AT  
DOUGLAS PASS. OTHER AREAS IN THE WIND ADVISORY ARE FLIRTING WITH  
UPPER 30S AND LOW 40S BUT DO EXPECT CRITERIA TO HIT AS THE  
STRONGER UPPER LEVEL JET WORKS OVERHEAD LATE THIS AFTERNOON AND  
EARLY EVENING ACROSS SOUTHEAST UTAH INTO NORTHWEST COLORADO. THIS  
SUFFICIENT MIXING HAS ALSO RESULTED IN MUCH WARMER AFTERNOON TEMPS  
SO BUMPED UP TEMPERATURES A BIT ABOVE GUIDANCE. THE WIND ADVISORY  
WILL CONTINUE UNTIL 8 PM MDT THIS EVENING, BEFORE DECOUPLING  
OCCURS POST-FRONTAL AND WITH THE SETTING SUN.  
 
A STRONG COLD FRONT WILL MARCH ACROSS THE AREA WITH A NOTICEABLE  
WIND SHIFT FROM SOUTHWEST TO NORTHWEST THIS EVENING AND OVERNIGHT  
AS IT PASSES THROUGH. THE FRONT LOOKS TO ENTER NORTHEAST UTAH  
AROUND 6 PM, MOVE ACROSS NORTHWEST COLORADO AND BE NEAR THE  
BOOKCLIFFS BY 9 PM AND MOVE THROUGH THE REST OF THE FORECAST AREA  
AND BE OVER THE SAN JUANS BY MIDNIGHT. THIS SYSTEM WILL ALSO BRING  
SOME SHOWERS TO THE REGION THIS EVENING THROUGH SATURDAY MORNING  
WITH NORTHERN AND CENTRAL AREAS OF WESTERN COLORADO FAVORED. THE  
NORTHERN AND CENTRAL MOUNTAINS LOOK TO PICK UP ABOUT 2 TO 4 INCHES  
OF SNOW AS MUCH COLDER AIR MOVES IN BEHIND THIS COLD FRONT AND  
TROUGH PASSAGE. H7 TEMPS LOWER TO -8C UP NORTH WITH -10C AIR AFTER  
SUNRISE UP NORTH. EXPECT PRECIP TO QUICKLY COME TO AN END AFTER  
SUNRISE SATURDAY MORNING AS DRY AIR QUICKLY PUNCHES IN WITH A 110  
KT UPPER LEVEL JET HELPING TO PUSH THIS SYSTEM TO THE EAST. A FEW  
LINGERING SHOWERS AND CLOUDS MAY REMAIN ALONG THE DIVIDE THROUGH  
THE MORNING HOURS BUT SHOULD CLEAR OUT AS THE DAY WEARS ON. DUE  
TO THE QUICK NATURE OF THIS SYSTEM AND LIMITED MOISTURE, ELECTED  
NOT TO ISSUE ANY WINTER WEATHER HIGHLITES AS THE MODELS AND  
FORECAST HAS CONSISTENTLY SHOWED 1 TO 4 INCHES AT BEST, WHICH IS  
BELOW ADVISORY CRITERIA, EVEN FOR EARLY SEASON.  
 
THE REST OF SATURDAY LOOKS DRY AND NOTICEABLY COOLER AS NORTHWEST  
FLOW SETS UP BEHIND THIS SYSTEM. BREEZY CONDITIONS MAY STILL  
REMAIN DUE TO THE UPPER LEVEL JET OVERHEAD. DAYTIME HIGHS ON  
SATURDAY WILL BE SOME 20 DEGREES COLDER THAN SEEN TODAY (FRIDAY)  
WITH HIGHS 10 DEGREES BELOW NORMAL.  
   
LONG TERM
 
(SUNDAY THROUGH FRIDAY)  
ISSUED AT 342 PM MDT FRI OCT 20 2017  
 
NORTHWEST FLOW WILL REMAIN IN THE PICTURE SUNDAY THROUGH EARLY  
NEXT WEEK AS HIGH PRESSURE BUILDS OVER THE DESERT SOUTHWEST AND  
BEGINS TO AMPLIFY ACROSS THE WEST COAST BY MID-WEEK. A SLOW  
WARMING TREND IS IN STORE WITH TEMPS WARMING BACK UP TO ABOVE  
NORMAL LEVELS BY MONDAY. SOME MID AND HIGH CLOUDS WILL MOVE  
THROUGH ACROSS THE NORTH ON MONDAY AS A TROUGH MOVES ACROSS THE  
NORTHERN HIGH PLAINS, HAVING LITTLE EFFECT ON OUR AREA OTHER THAN  
SOME CLOUDS AND BREEZY CONDITIONS. THE NEXT CHANCE OF  
PRECIPITATION ARRIVES ON THURSDAY AS A STRONG AND DEEP TROUGH OF  
LOW PRESSURE MOVES THROUGH THE NORTHERN ROCKIES AND DOWN THE FRONT  
RANGE. THIS SYSTEM LOOKS MUCH COLDER THAN ANYTHING SEEN SO FAR  
THIS FALL WITH H7 TEMPS DROPPING INTO THE -10C (SOUTH) TO -16C  
(NORTH) RANGE. THIS WOULD MEAN PRECIPITATION QUICKLY CHANGING OVER  
TO SNOW AS THE LEADING EDGE MOVES SOUTHWARD THROUGHOUT THE DAY  
AND SNOW LEVELS LOWERING TO ALL VALLEY FLOORS. HAVING SAID THAT,  
SNOW LOOKS TO FAVOR THE HIGHER TERRAIN OF WESTERN COLORADO AND  
HIGHER VALLEYS ALONG THE DIVIDE, WITH THE FRONT RANGE TAKING THE  
BRUNT OF THIS SYSTEM. MODELS ARE IN FAIRLY GOOD AGREEMENT TODAY ON  
THE TIMING AND TRACK OF THIS SYSTEM BUT WERE NOT IN COMPLETE  
AGREEMENT ON HOW FAR WEST TO TAKE THIS SYSTEM FROM RUN TO RUN. THE  
DETAILS ARE SUBJECT TO CHANGE AS WE GET CLOSER TO THIS EVENT, BUT  
SOMETHING TO WATCH AS THIS POLAR AIRMASS ENCOMPASSES MUCH OF THE  
INTERMOUNTAIN WEST AND PLAINS THURSDAY INTO FRIDAY.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)  
ISSUED AT 542 PM MDT FRI OCT 20 2017  
 
GUSTY WINDS OUT OF THE WEST AND EVENTUALLY THE NORTHWEST WILL BE  
THE PRIMARY AVIATION HAZARD THROUGH THE EVENING HOURS AT ALL TAF  
SITES AS A STRONG COLD FRONT MOVES THROUGH THE REGION. SCATTERED  
SHOWERS OF RAIN AND SNOW WILL ACCOMPANY THE FRONT WHICH IS  
CURRENTLY SITUATED IN NORTHEASTERN UT. PERIODS OF MOUNTAIN  
OBSCURATION AND REDUCED CIGS/VIS CAN BE EXPECTED WITH HEAVIER  
SHOWERS. SHOWER AND WIND ACTIVITY WILL DIMINISH FROM NE TO SE  
OVERNIGHT AS SIGNIFICANT CLEARING OCCURS BEHIND THE FRONT. BY 12Z  
SATURDAY ONLY SOME ISOLATED SHOWERS WILL LINGER ALONG THE  
CONTINENTAL DIVIDE WITH WIDESPREAD VFR CONDITIONS RETURNING  
SHORTLY AFTER.  
 

 
   
GJT WATCHES/WARNINGS/ADVISORIES
 
 
CO...NONE.  
UT...NONE.  

 
 

 
 
UPDATE...JDC  
SHORT TERM...MDA  
LONG TERM...MDA  
AVIATION...TGJT  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab CO Page
The Nexlab UT Page Main Text Page