723  
FXUS65 KSLC 252143  
AFDSLC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SALT LAKE CITY UT  
343 PM MDT FRI MAY 25 2018  
   
SYNOPSIS
 
WARM AND DRY SOUTHERLY FLOW TODAY WILL GIVE WAY TO  
INCREASINGLY UNSETTLED CONDITIONS DURING THE UPCOMING HOLIDAY  
WEEKEND AS A SLOW MOVING LOW PRESSURE SYSTEM MAKES ITS WAY ACROSS  
THE AREA. HIGH PRESSURE IS EXPECTED TO RETURN FOR THE MIDDLE OF  
NEXT WEEK.  
 

 
   
SHORT TERM (THROUGH 06Z TUESDAY)
 
THE FORECAST AREA IS UNDER A  
WARM AND DRY SOUTHERLY FLOW THIS AFTERNOON AHEAD OF THE STORM  
SYSTEM MOVING ONSHORE OVER CALIFORNIA. MAXES TODAY ARE RUNNING  
10-15F ABOVE SEASONAL NORMALS FOR MOST LOCATIONS AND EVEN WARMER  
IN SOME LOCATIONS THAT DO WELL IN SOUTHERLY FLOW LIKE THE SALT  
LAKE VALLEY.  
 
THE CALIFORNIA STORM SYSTEM WILL EASE ITS WAY INTO WESTERN UTAH BY  
TOMORROW AFTERNOON, SLOWLY MOVING ACROSS THE FORECAST AREA THROUGH  
TUESDAY. A FEW SHOWERS ARE ANTICIPATED, PRIMARILY OVER THE HIGHER  
TERRAIN OF NORTHERN UTAH, TOMORROW AFTERNOON AS MOISTURE AND  
INSTABILITY STARTS TO INCREASE. HOWEVER, THINK SUNDAY AND MONDAY  
WILL BOTH SEE BETTER COVERAGE, FOCUSED OVER NORTHERN AND CENTRAL  
PORTIONS OF THE FORECAST AREA, AS THE COLD POOL MOVES THROUGH.  
HAVE RAISED POPS JUST A BIT WITH INCREASING CONFIDENCE. TEMPERATURES  
WILL ALSO COOL NOTICEABLY BY SUNDAY, WITH MAXES RUNNING NEAR OR  
JUST BELOW SEASONAL NORMALS.  
 
   
LONG TERM (AFTER 06Z TUESDAY)
 
THE CLOSED LOW FROM THE MEMORIAL  
DAY HOLIDAY WILL CONTINUE TO FILL AND WEAKEN AS IT PULLS NORTHEAST  
OF OUR AREA LATE MONDAY INTO TUESDAY. A FEW LINGERING SHOWERS ARE  
POSSIBLE (ESPECIALLY IF THE CLOSED LOW SLOWS DOWN), BUT OTHERWISE  
CLEARING SKIES AND A WARMING TREND CAN BE EXPECTED BY LATER TUESDAY  
AS A RIDGE BUILDS IN OVER THE GREAT BASIN.  
 
THE WEATHER PATTERN OVER THE WESTERN US BEGINS A NOTABLE TRANSITION  
TOWARDS THE MIDDLE OF NEXT WEEK. THE GENERAL THEME OVER THE LAST FEW  
WEEKS HAS BEEN A PARADE OF CLOSED LOWS MEANDERING INTO THE GREAT  
BASIN. IN CONTRAST, GLOBAL MODELS ARE SHOWING A CONSOLIDATED  
LONGWAVE TROUGH DEVELOPING ALONG THE WEST COAST BY THE MIDDLE OF  
NEXT WEEK. IN ADVANCE OF THAT TROUGH, MODELS INDICATE STRENGTHENING  
SOUTHWEST FLOW OVER OUR AREA, BRINGING WARMER TEMPERATURES AND  
BREEZY CONDITIONS FOR THE WEDNESDAY/THURSDAY TIMEFRAME. AFTERNOON  
SHOWERS/THUNDERSTORMS CAN'T BE RULED OUT UNDER THIS PATTERN,  
MAINLY OVER THE HIGHER TERRAIN OF UTAH WITH A SLIGHT CHANCE FOR  
NORTHERN UTAH AND SOUTHWEST WYOMING VALLEYS. FORECAST CONFIDENCE  
THEN DROPS OFF QUICKLY WITH THE EVOLUTION OF THE AFOREMENTIONED  
TROUGH. MODELS STRUGGLE WITH THE TROUGH AS IT MOVES INLAND; THE  
ECMWF PUSHES A WEAKENING TROUGH AXIS THROUGH THE GREAT BASIN  
THURSDAY INTO FRIDAY WITH A CHANCE OF PRECIPITATION AND COOLING  
TREND FOR US, WHILE THE GFS AND CANADIAN PUSH A DEEPER TROUGH  
INLAND ABOUT TWO DAYS LATER. IN EITHER CASE, THE GENERAL THEME IS  
COOLER AND PERHAPS WETTER TOWARDS THE END OF NEXT WEEK.  
 

 
   
AVIATION
 
VFR CONDITIONS WITH CLEAR SKIES WILL CONTINUE AT THE SLC  
TERMINAL FOR THE REST OF TODAY AND INTO TONIGHT. SOUTHERLY WINDS  
SHOULD GIVE WAY TO A LIGHT NORTHWESTERLY LAKE BREEZE BY 22Z-23Z,  
THEN RETURN TO THE SOUTHEAST BETWEEN 03Z AND 05Z THIS EVENING.  
 

 
   
FIRE WEATHER
 
A WARM AND BREEZY SOUTHERLY FLOW IS OVER THE  
DISTRICT TODAY AHEAD OF THE NEXT APPROACHING PACIFIC STORM SYSTEM.  
THIS SYSTEM WILL MOVE INTO THE AREA BEGINNING TOMORROW, SLOWLY  
MAKING ITS WAY ACROSS UTAH THROUGH TUESDAY. SOME HIGH BASED  
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP SATURDAY  
AFTERNOON ACROSS THE HIGHER TERRAIN OF NORTHERN UTAH. SHOWERS AND  
THUNDERSTORMS WILL BECOME MORE WIDESPREAD OVER NORTHERN AND  
CENTRAL UTAH SUNDAY INTO MONDAY AS THE LOW CONTINUES ACROSS THE  
STATE. TEMPERATURES WILL ALSO COOL WITH THE PASSAGE OF THIS LOW,  
RETURNING TO NEAR SEASONAL NORMALS BY SUNDAY.  
 

 
   
SLC WATCHES/WARNINGS/ADVISORIES
 
 
UT...NONE.  
WY...NONE.  

 
 

 
 
SHORT TERM/FIRE WEATHER...TRAPHAGAN  
LONG TERM/AVIATION...VAN CLEAVE  
 
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/SALTLAKECITY  
 
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION  
VISIT...  
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP  
 
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