440  
FXUS65 KPUB 181723  
AFDPUB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PUEBLO CO  
1123 AM MDT WED SEP 18 2019  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 359 AM MDT WED SEP 18 2019  
 
SW UPPER FLOW OVER CO GRADUALLY STRENGTHENS TODAY AS NEXT UPPER  
TROUGH DIGS INTO THE PACIFIC NW. WITH 700 MB WINDS INCREASING TO 20-  
30 KTS AND 500 MB WINDS TO 30-40 KTS, MOUNTAINS WILL BECOME BREEZY  
TO WINDY IN SPOTS BY AFTERNOON, ESPECIALLY OVER THE HIGHER TERRAIN  
ALONG THE CONTINENTAL DIVIDE. PLAINS WINDS A LITTLE SLOWER TO  
INCREASE, THOUGH WITH GRADUALLY DEEPENING LEE SURFACE TROUGH, S-SE  
FLOW WILL PRODUCE SOME GUSTS OF 20-25 KTS BY LATE AFTERNOON. A FEW  
MODELS SUGGEST JUST ENOUGH MOISTURE AND INSTABILITY FOR SOME VERY  
WEAK/ISOLATED CONVECTION OVER THE HIGHER TERRAIN FROM TELLER COUNTY  
NORTHWARD AS MINOR SHORT WAVE TROUGH RIPPLES THROUGH THE REGION, AND  
WILL KEEP SOME LOW POPS IN PLACE FOR JUST A COUPLE HRS LATE IN THE  
DAY. OVERNIGHT, JUST ENOUGH FLOW ALOFT TO PRODUCE SOME OCCASIONALLY  
BREEZY CONDITIONS, WHICH WILL LEAD TO OVERNIGHT LOW TEMPS A COUPLE  
DEGF WARMER THAN THE PAST FEW NIGHTS AT MANY LOCATIONS.  
   
LONG TERM
 
(THURSDAY THROUGH TUESDAY)  
ISSUED AT 359 AM MDT WED SEP 18 2019  
 
THURSDAY - FRIDAY...  
 
AN IMPRESSIVE TROUGH OVER THE WESTERN US THURSDAY MORNING WILL DIG  
INTO THE GREAT BASIN THURSDAY THROUGH THURSDAY NIGHT, AND LIFT  
NORTHEAST ACROSS NORTHERN COLORADO AND INTO THE NORTHERN US PLAINS  
BY FRIDAY NIGHT. MOISTURE OVER THE HIGH TERRAIN WILL INCREASE  
SLIGHTLY AHEAD OF THE SYSTEM, AND COMBINED WITH STRONG QG FORCING  
FOR ASCENT AND DAYTIME HEATING, WILL RESULT IN ISOLATED TO  
SCATTERED THUNDERSTORM DEVELOPMENT OVER THE HIGH TERRAIN THURSDAY  
INTO THURSDAY EVENING, WITH BEST CHANCES OVER THE CONTINENTAL  
DIVIDE CLOSEST TO THE BEST FORCING. MOUNTAIN THUNDERSTORMS WILL  
LINGER INTO FRIDAY MORNING, MOSTLY DISSIPATING BY EARLY FRIDAY  
EVENING AS THE TROUGH LIFTS TO THE NORTHEAST.  
 
FURTHER EAST, A DRYLINE IS EXPECTED TO DEVELOP ALONG THE EASTERN  
PERIPHERY OF A SURFACE LEE TROUGH NEAR THE CO/KS BORDER THURSDAY,  
WITH SOME UNCERTAINTY AS TO EXACTLY HOW FAR WEST, IF AT ALL,  
MOISTURE MAKES IT INTO COLORADO. SURFACE DEW POINTS ON THE MOIST  
SIDE SHOULD REACH NEAR 60, SO ISOLATED TO SCATTERED STORMS  
DEVELOPING ALONG THE BOUNDARY COULD BE STRONG. WITH BEST MID LEVEL  
FLOW BACK WEST CLOSER TO THE UPPER TROUGH, SHEAR WILL LIMIT  
SEVERE POTENTIAL. WEST OF THE DRY LINE AND OVER THE I-25  
CORRIDOR, CONDITIONS SHOULD REMAIN DRY THURSDAY. ALL OF THE PLAINS  
WILL BECOME DRY FRIDAY AS DRY AIR FILTERS IN BEHIND THE TROUGH.  
 
TEMPERATURES ON THURSDAY AND FRIDAY WILL RISE TO NEAR 90 ACROSS THE  
PLAINS DURING THE AFTERNOONS, MID 80S IN COLORADO SPRINGS, AND 70S  
ACROSS THE HIGH VALLEYS. ENHANCED MID-LEVEL FLOW ASSOCIATED WITH THE  
UPPER TROUGH WILL MIX TO THE SURFACE DURING THE DAY FRIDAY, LEADING  
TO GUSTY SOUTHWEST WINDS. EXPECT GUSTS IN THE 30-40 MPH RANGE  
ACROSS THE PLAINS AND HIGH VALLEYS FRIDAY AFTERNOON. ALTHOUGH  
SURFACE RH VALUES WILL DROP ON FRIDAY, THEY LIKELY WON'T REACH  
CRITICAL LEVELS. HOWEVER THE STRONG WINDS, NEAR-CRITICAL RH  
VALUES, AND INCREASINGLY DRY FUELS WILL LEAD TO AT LEAST ELEVATED  
FIRE DANGER.  
 
SATURDAY - SUNDAY...  
 
THE AFOREMENTIONED UPPER TROUGH WILL SEND A SURFACE COLD FRONT SOUTH  
DOWN THE EASTERN COLORADO PLAINS FRIDAY EVENING, LEADING TO COOLER  
TEMPERATURES FOR SATURDAY. ANOTHER TROUGH, BUT QUICK-MOVING AND  
WEAKER THAN THE PREVIOUS, WILL SWING ACROSS COLORADO DURING THE  
DAY/EVENING SATURDAY. ALTHOUGH THIS FEATURE WILL SPREAD ANOTHER  
ROUND OF LARGE SCALE FORCING ACROSS THE STATE, DRY ANTECEDENT  
CONDITIONS WILL LIMIT PRECIPITATION CHANCES, WITH ONLY ISOLATED  
SHOWERS AND STORMS EXPECTED OVER THE MOUNTAINS. THE TROUGH WILL  
SEND ANOTHER COLD FRONT WITH INCREASED MOISTURE SOUTH DOWN THE  
EASTERN PLAINS SATURDAY NIGHT, ALONG/BEHIND WHICH ISOLATED TO  
WIDELY SCATTERED SHOWERS AND STORMS ARE FORECAST. THIS ACTIVITY  
SHOULD REMAIN NEAR/NORTH OF HWY 50. SHORTWAVE RIDING WILL LEAD TO  
DRY CONDITIONS ACROSS SOUTHERN COLORADO ON SUNDAY.  
 
GIVEN THE FRONTAL PASSAGES FRIDAY NIGHT AND SATURDAY NIGHT,  
TEMPERATURES WILL BE COOLER DURING THE WEEKEND. HIGHS WILL BE IN THE  
LOW TO MID 80S ACROSS THE PLAINS, UPPER 70S IN COLORADO SPRINGS, AND  
60S TO 70S ACROSS THE HIGH VALLEYS. OVERNIGHT LOWS WILL BE COLDEST  
ACROSS THE REGION SATURDAY NIGHT, WITH TEMPERATURES DIPPING NEAR OR  
BELOW FREEZING ACROSS THE HIGH MOUNTAIN VALLEYS, AND INTO THE MID TO  
UPPER 40S ACROSS THE PLAINS. FIRE WEATHER CONDITIONS SHOULD REMAIN  
ELEVATED OVER THE WEEKEND, MAINLY ACROSS THE HIGH TERRAIN.  
 
MONDAY - TUESDAY...  
 
THE NEXT MORE SIGNIFICANT UPPER LEVEL TROUGH DIGS INTO THE WESTERN  
US BY MONDAY AND LIKELY INTO THE SOUTHWEST US BY TUESDAY AS A CLOSED  
LOW. DETERMINISTIC AND ENSEMBLE MODEL SOLUTIONS DIFFER SIGNIFICANTLY IN  
THE EXACT POSITION OF THE UPPER LOW BY TUESDAY, PLACING IT ANYWHERE  
FROM OFF THE CALIFORNIA COAST TO THE FOUR CORNERS. ADDITIONALLY,  
SOME SOLUTIONS BRING MOISTURE ASSOCIATED WITH A EPAC TROPICAL  
SYSTEM AROUND THE EASTERN SIDE OF THE CLOSED LOW AND OVER  
COLORADO, RESULTING IN ABUNDANT PRECIPITATION. HOWEVER, GIVEN THE  
CONSIDERABLE MODEL DIFFERENCES, CONFIDENCE IS LOW IN THE  
PRECIPITATION FORECAST OVER SOUTHERN COLORADO NEXT WEEK.  
TEMPERATURES APPEAR LIKELY TO REMAIN IN THE 80S ACROSS THE PLAINS  
EARLY NEXT WEEK, AND 70S TO LOW 80S IN COLORADO SPRINGS.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)  
ISSUED AT 1130 AM MDT WED SEP 18 2019  
 
GENERALLY DRY SOUTHWESTERLY UPPER FLOW OVER SOUTHERN COLORADO IS  
EXPECTED TO ALLOW VFR CONDITIONS TO CONTINUE OVER THE KALS, KCOS  
AND KPUB TAF SITES DURING THE NEXT 24 HOURS.  
 

 
   
PUB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
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