661  
FXUS65 KGJT 201746  
AFDGJT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
1046 AM MST WED FEB 20 2019  
   
SHORT TERM
 
(TODAY THROUGH THURSDAY)  
ISSUED AT 327 AM MST WED FEB 20 2019  
 
WINTER STORM WARNINGS AND WINTER STORM WATCHES ARE IN EFFECT OVER  
PORTIONS OF OVER CENTRAL AND SOUTHERN UTAH AND COLORADO IN  
ANTICIPATION OF THE NEXT PACIFIC STORM. THE REMNANTS OF MONDAY AND  
TUESDAY'S STORM HAVE BEEN SLOW TO DISSIPATE AS NUMEROUS SHOWERS  
WILL REMAIN OVER THE MOUNTAINS OF THE CONTINENTAL DIVIDE THROUGH  
ABOUT MIDMORNING. ISOLATED TO SCATTERED SHOWERS WILL CONTINUE THIS  
MORNING OVER THE REST OF WESTERN CO AND NORTHEAST UT AS WELL.  
 
THE NEXT STORM IS DEVELOPING OVER THE PACIFIC NORTHWEST THIS  
MORNING AND WILL STRENGTHEN AS IT TRAVELS SOUTHEAST TO THE GREAT  
BASIN TONIGHT. AHEAD OF THE SYSTEM WINDS WILL GRADUALLY SLIDE WEST  
THEN SOUTHWEST BY EARLY THIS EVENING. MOISTURE WILL INCREASE AND  
ENHANCED OROGRAPHIC SNOWFALL SHOULD DEVELOP ACROSS THE MOUNTAINS  
OF SOUTHEAST UT AND SOUTHWEST CO.  
 
BY ABOUT MIDNIGHT TONIGHT THE SURFACE LOW SHOULD BE CENTERED OVER  
LAS VEGAS WITH THE UPPER LOW CLOSING OFF AND BECOMING VERTICALLY  
STACKED OVER SOUTHERN NV THURSDAY MORNING. THURSDAY AFTERNOON IT  
APPEARS THE LOW CENTER WILL SPLIT WITH A SIGNIFICANT PORTION OF  
ITS ENERGY DIGGING TO SOUTHERN CA. THIS TURNS WINDS ALOFT TO THE  
SOUTH-SOUTHWEST WITH THE JET STREAM TRAVELING JUST EAST OF THE  
FOUR CORNERS THEN NORTH OVER THE CONTINENTAL DIVIDE. THIS  
ORIENTATION SHOULD BRING PERIODS OF HEAVY SNOWFALL TO THE SAN JUAN  
MOUNTAINS AND FOOTHILLS AND ANY MOUNTAIN RANGES FAVORING  
SOUTHWESTERLY OROGRAPHICS.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 327 AM MST WED FEB 20 2019  
 
SNOW WILL CONTINUE TO BE HEAVY OVER THE SOUTHERN HALF OF THE  
FORECAST AREA THURSDAY NIGHT AS THE JET SLIDES EASTWARD OVER THE  
AREA. SNOWFALL WILL ALSO BE WIDESPREAD OVER THE CENTRAL MOUNTAINS  
AND ADJACENT VALLEYS, THOUGH ACCUMULATIONS AREN'T EXPECTED TO BE  
QUITE AS IMPRESSIVE WHEN COMPARED TO THE SOUTH. SOUTHWEST RIDGETOP  
WINDS AT 30 KTS WILL LEAD TO BLOWING SNOW, SIGNIFICANTLY REDUCING  
VISIBILITY AT TIMES. THE TROUGH AXIS WILL BE MOVING OVER THE  
FORECAST AREA ON FRIDAY ENHANCING INSTABILITY WHILE WINDS WEAKEN  
AND SHIFT TO THE WEST. SNOW WILL CONTINUE OVER THE SOUTHERN AND  
CENTRAL PORTION OF THE FORECAST AREA DURING THE DAY, FINALLY  
BECOMING SCATTERED IN COVERAGE FRIDAY NIGHT.  
 
NORTHWESTERLY FLOW ON THE BACK SIDE OF THIS SECOND PROLONGED  
WINTER STORM WILL BRING MUCH QUIETER WEATHER TO THE REGION THIS  
WEEKEND INTO EARLY NEXT WEEK. HOWEVER, MODELS WERE CONSISTENT IN  
SHOWING SOME SHALLOW, FAST MOVING SHORTWAVES MOVING THROUGH THE  
INCREASINGLY ZONAL FLOW WILL BRING OCCASIONAL LIGHT SNOW TO THE  
NORTHERN MOUNTAINS. MODELS STRUGGLE WITH TIMING AND IMPACTS OF  
SUCH SHALLOW DISTURBANCES SO DIFFICULT TO PUT MUCH DETAIL IN THE  
FORECAST IN THESE LATER PERIODS.  
 
TEMPERATURE WISE, LOOK FOR READINGS TO RUN LOW FOR THIS TIME OF  
YEAR THROUGH THE WEEKEND WITH A GRADUAL TREND TOWARD NORMAL  
READINGS BY THE MIDDLE OF NEXT WEEK.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)  
ISSUED AT 1046 AM MST WED FEB 20 2019  
 
SNOW SHOWERS WILL REDEVELOP OVER SOUTHEAST UT/SOUTHWEST CO BY LATE  
THIS AFTERNOON AS A STRONG DISTURBANCE DROPS INTO THE DESERT  
SOUTHWEST. AMPLE MOISTURE IN THE SOUTHWESTERLY FLOW WILL RESULT IN  
WIDESPREAD PRECIPITATION ACROSS MUCH OF THE REGION BETWEEN 06-09Z  
TONIGHT. BY THEN, EXPECT CIGS AT ALL TAF SITES TO DROP TO ILS  
BREAKPOINTS. IN SHOWERS, EXPECT PERIODS OF MVFR/IFR CONDITIONS  
WITH REDUCED VIS/CIGS. MOUNTAINS WILL FREQUENTLY BE OBSCURED.  
NUMEROUS SHOWERS WILL PERSIST ACROSS THE FORECAST AREA THROUGH 18Z  
THURSDAY AFTERNOON.  
 

 
   
GJT WATCHES/WARNINGS/ADVISORIES
 
 
CO...WINTER STORM WATCH FROM THIS EVENING THROUGH FRIDAY AFTERNOON  
FOR COZ003-009-012-017.  
 
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST FRIDAY  
FOR COZ018>023.  
 
UT...WINTER STORM WATCH FROM THIS EVENING THROUGH FRIDAY AFTERNOON  
FOR UTZ025.  
 
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST FRIDAY  
FOR UTZ022-028-029.  
 

 
 

 
 
SHORT TERM...CC  
LONG TERM...NL  
AVIATION...MMS  
 
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