989  
FXUS65 KSLC 192058  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
258 PM MDT FRI AUG 19 2022  
   
SYNOPSIS
 
MONSOON MOISTURE WILL REMAIN IN PLACE ACROSS THE  
REGION THROUGH SATURDAY. DRIER AIR WILL BUILD INTO THE STATE  
SUNDAY INTO EARLY NEXT WEEK, GIVING A REPRIEVE FROM THE MONSOON,  
WITH ANOTHER SURGE POSSIBLE MID TO LATE WEEK.  
 

 
   
SHORT TERM (THROUGH 12Z/6AM SUNDAY)
 
EARLY AFTERNOON ANALYSIS  
INDICATES AN INTERESTING PATTERN IN PLACE ACROSS UTAH AND SW  
WYOMING. AN UPPER LOW IS PARKED NEAR THE ID/OR/NV BORDER REGION  
WITH A TRAILING SHORTWAVE IN PLACE ACROSS CENTRAL UTAH. STEERING  
FLOW IS OUT OF THE WEST-NORTHWEST ACROSS SOUTHWEST UTAH, OUT OF  
THE SOUTH ACROSS SOUTHEAST UTAH, AND EASTERLY ACROSS NORTHEAST  
UTAH AND SOUTHWEST WYOMING. NEARLY NULL/ZERO FLOW IS IN PLACE  
FROM NW UTAH SOUTHEAST INTO CENTRAL UTAH -- A COMPLEX SETUP  
INDEED. AN AREA OF SHOWERS IS DRAPED ALONG THIS NULL FLOW REGION,  
COINCIDENT WITH THE AREA OF GREATEST MID-LEVEL ASCENT. ON EITHER  
SIDE OF THE CLOUD SHIELD, PLENTIFUL SUNSHINE IS IN PLACE ACROSS  
BOTH SW UTAH AND NE UTAH AND SW WYOMING, LEADING TO GRADUAL  
DESTABILIZATION PER SATELLITE AND MESOANANLYSIS. DIFFERENTIAL  
HEATING BOUNDARIES ARE SETTING UP ON EITHER SIDE OF THIS CLOUD  
SHIELD. MEANWHILE, AN AXIS OF >1" PWAT IS IN PLACE ACROSS  
SOUTHERN UTAH, AND EXTENDS NORTHWARD TO INCLUDE NW UTAH AND THE  
WASATCH FRONT. FINALLY, UPPER DIFFLUENCE IS MAXIMIZED ACROSS  
NORTHERN UTAH, WITHIN THE DEFORMATION REGION ASSOCIATED WITH THE  
UPPER LOW. YOU MIGHT WONDER...HOW MIGHT THIS COMPLICATED SETUP  
EVOLVE OVER THE REST OF THE AFTERNOON?  
 
WE'VE ALREADY SEEN THUNDERSTORMS CONTAINING HEAVY RAINFALL OVER  
ZION NP AND MORE RECENTLY NEAR HILDALE. CAMS SUGGEST THIS ACTIVITY  
WILL CONTINUE TO SLOWLY TRACK SOUTH AND EAST OVER THE REMAINDER OF  
THE AFTERNOON WITH AN ATTENDANT HEAVY RAINFALL AND FLASH FLOOD  
THREAT FOR NORMALLY DRY WASHES, SLICKROCK, SLOT CANYONS AND OTHER  
FLOOD-PRONE AREAS. MEANWHILE, CAMS ARE IN EXCELLENT AGREEMENT IN  
DEVELOPING A CLUSTER OF SHOWER AND THUNDERSTORMS ALONG/EAST OF THE  
WASTACH, ULTIMATELY TRACKING THIS ACTIVITY WESTWARD ACROSS THE  
WASATCH FRONT BETWEEN 3PM-7PM. THIS ACTIVITY WILL BE CAPABLE OF  
PRODUCING GUSTY OUTFLOW WINDS (FROM AN ATYPICAL EASTERLY  
DIRECTION) AS WELL AS HEAVY RAINFALL WHICH MAY LEAD TO SOME  
URBAN/SMALL STREAM FLOODING. AS WE HEAD THROUGH THE EVENING,  
HEAVIEST CONVECTION WILL GRADUALLY DIMINISH, ESPECIALLY ACROSS  
SOUTHERN UTAH WHERE ASCENT IS LESS AND A MID-LEVEL DRY SLOT WILL  
TRY AND NUDGE INTO THIS AREA. FARTHER NORTH, AN AREA OF SHOWERS IS  
EXPECTED TO CONTINUE FOR MUCH OF THE NIGHT IN THE  
DIFFLUENT/DEFORMATION AXIS ASSOCIATED WITH THE APPROACHING UPPER  
LOW. AREAS MOST FAVORED FOR NOCTURNAL SHOWERS INCLUDES NORTHERN  
UTAH, NE UTAH AND EASTERN UTAH. MOST OF THIS ACTIVITY IS EXPECTED  
TO REMAIN ON THE LIGHT TO OCCASIONALLY MODERATE SIDE.  
 
ON SATURDAY, THE AFOREMENTIONED UPPER LOW IS FORECAST TO MEANDER  
EASTWARD ACROSS NORTHERN UTAH, BECOMING CENTERED NEAR PROVO. THIS  
LOW WILL ACT TO INCREASE LAPSE RATES AND LOWER LCLS. WIDESPREAD  
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AFTERNOON  
AS A RESULT, WITH COVERAGE MAXIMIZED OVER NORTHERN AND CENTRAL  
UTAH, ESPECIALLY ALONG/EAST OF I-15. THIS ACTIVITY ALSO HAS THE  
POTENTIAL TO PROMOTE LOCALIZED FLOODING CONCERNS AS COPIOUS LOW TO  
MID-LEVEL MOISTURE WILL REMAIN IN PLACE. SIMILAR TO THIS EVENING,  
ACTIVITY IS EXPECTED TO GRADUALLY WANE THROUGH THE EVENING.  
 
   
LONG TERM (AFTER 12Z/6AM SUNDAY)
 
ON SUNDAY INTO MONDAY, AN  
UPPER LEVEL TROUGH IS FORECAST TO SWING EASTWARD ACROSS THE  
PACIFIC NORTHWEST AND NORTHERN ROCKIES. AT THE SAME TIME, A RIDGE  
OF HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE GREAT BASIN. THIS  
PROCESS WILL ACT TO SHIFT THE AXIS OF MONSOONAL MOISTURE OFF TO  
THE EAST, INITIATING A DRYING TREND ACROSS THE REGION. HOWEVER,  
ENOUGH LOW-LEVEL MOISTURE WILL LINGER FOR AREAS GENERALLY  
ALONG/EAST OF I-15 TO SUPPORT ADDITIONAL SHOWER/THUNDERSTORM  
ACTIVITY WITH AN ISOLATED HEAVY RAINFALL THREAT. THE DRYING TREND  
WILL CONTINUE MONDAY WITH SHOWERS/THUNDERSTORMS EXPECTED TO BE  
LIMITED TO MAINLY HIGH TERRAIN AREAS. CONTINUED DRYING ON TUESDAY  
SUGGESTS LITTLE TO NO PRECIPITATION POTENTIAL. WITH THIS DRYING  
TREND, A WARMING TREND IS EXPECTED AS WELL.  
 
FOR THE MIDDLE TO LATER HALF OF NEXT WEEK, ENSEMBLES AND  
DETERMINISTIC GUIDANCE IS IN REASONABLE AGREEMENT IN THEIR  
RELATIVE DEPICTIONS OF MONSOONAL MOISTURE GRADUALLY RETURNING TO  
THE AREA. ENOUGH MOISTURE APPEARS TO BE IN PLACE BY WEDNESDAY TO  
SUPPORT MAINLY HIGH TERRAIN SHOWERS/THUNDERSTORMS -- WITH A FEW  
POTENTIALLY SNEAKING INTO SOUTHWEST UTAH AS WELL. IT DOES APPEAR  
THAT WIDESPREAD SHOWERS AND THUNDERSTORMS RETURN BY THURSDAY AND  
FRIDAY OF NEXT WEEK, ALTHOUGH THE DEPTH OF MOISTURE REMAINS  
UNCERTAIN AT THIS POINT. JUST OVER HALF OF THE SOLUTION SPACE  
DEPICTS QPF ABOVE THE ENSEMBLE MEAN, AND THIS SUPPORTS THE BROAD  
POP COVERAGE CURRENTLY IN OUR OFFICIAL FORECAST.  
 

 
   
AVIATION...KSLC
 
PREDOMINANTLY VFR CONDITIONS ARE EXPECTED FOR  
KSLC. DRY CONDITIONS TO START FOLLOWED BY AN INCREASED CHANCE FOR  
SHOWERS AND THUNDERSTORMS AROUND 22Z AND LASTING UNTIL AROUND 01Z.  
GUSTY AND ERRATIC OUTFLOW WINDS WILL BE POSSIBLE DURING THIS TIME.  
PRECIPITATION CHANCES WILL BE ON AND OFF OVERNIGHT AND INTO THE DAY  
TOMORROW. THERE IS CURRENTLY A BOUNDARY OVER THE AIRFIELD WITH  
SOUTHERLY WINDS ON THE SOUTH SIDE AND WESTERLY WINDS ON THE NORTH  
SIDE THAT WILL REMAIN IN PLACE UNTIL THE EASTERLY OUTFLOW WINDS  
ARRIVE WITH SHOWERS AND STORMS THAT ARE STILL IN THE FORECAST. DROPS  
IN VISIBILITY OR LOWER CLOUD BASES WILL BE POSSIBLE WITH THESE  
STORMS.  
   
REST OF UTAH AND SOUTHWEST WYOMING
 
PREDOMINANTLY VFR  
CONDITIONS EXPECTED DURING THE PERIOD. SCATTERED SHOWERS AND  
THUNDERSTORMS ACROSS THE CWA WILL CONTINUE FOR THE REMAINDER OF THE  
DAY. MVFR CONDITIONS WILL BE POSSIBLE WHEN ONE OF THESE  
THUNDERSTORMS OR SHOWERS ARE NEARBY OR OVERHEAD. OTHER THAN GUSTY  
AND ERRATIC OUTFLOW WINDS THAT COULD ACCOMPANY THESE SHOWERS AND  
STORMS WINDS WILL BE DIURNALLY DRIVEN.  
 

 
   
FIRE WEATHER
 
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE FORECAST  
ACROSS MOST OF THE STATE THIS AFTERNOON AND EARLY EVENING AS WELL AS  
SATURDAY, WITH THE BULK OF THE PRECIPITATION SHIFTING ACROSS  
NORTHERN UTAH BY SATURDAY AFTERNOON. THIS WILL OCCUR AS AN AREA OF  
LOW PRESSURE DRIFTS EASTWARD DIRECTLY ACROSS NORTHERN UTAH DURING  
THE DAY SATURDAY. A DRYING TREND WILL THEN BEGIN TO BUILD INTO  
THE REGION SUNDAY. AS A RESULT, AFTERNOON SHOWERS/THUNDERSTORMS  
WILL BECOME CONFINED TO AREAS MAINLY ALONG/EAST OF I-15. THE  
DRYING TREND WILL CONTINUE ON MONDAY AS ANOTHER AREA OF LOW  
PRESSURE SLIDES ACROSS THE NORTHERN ROCKIES WHILE A RIDGE OF HIGH  
PRESSURE BUILDS ACROSS THE STATE. THIS WILL CAUSE AFTERNOON/EARLY  
EVENING SHOWER AND THUNDERSTORM COVERAGE WILL SHRINK TO MAINLY  
HIGH TERRAIN AREAS BY MONDAY.  
 
MAINLY DRY CONDITIONS ARE EXPECTED TUESDAY. A WARMING TREND WILL  
ACCOMPANY THE DRYING TREND, AS TEMPERATURES RISE TO NEAR TO JUST  
BELOW NORMAL SATURDAY TO NEAR TO JUST ABOVE NORMAL BY TUESDAY.  
MONSOONAL MOISTURE IS THEN EXPECTED TO GRADUALLY RETURN TO THE  
STATE BY THE MIDDLE TO LATER PORTION OF NEXT WEEK WITH SHOWER AND  
THUNDERSTORM CHANCES INCREASING ALONG WITH HUMIDITY.  
 

 
   
SLC WATCHES/WARNINGS/ADVISORIES
 
 
UT...FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR UTZ124>128.  
 
WY...NONE.  

 
 

 
 
ADESMET/CECAVA  
 
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