AREA FORECAST DISCUSSION

 
 FXUS65 KSLC 041617
 AFDSLC
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SALT LAKE CITY UT
 1015 AM MDT FRI JUL 4 2008
 
 .SYNOPSIS...INCREASING SOUTHWEST FLOW WILL BE OVER THE AREA TODAY
 AS A WEAKENING UPPER TROUGH MOVES INTO THE GREAT BASIN. THE
 ASSOCIATED COLD FRONT WILL SLOWLY CROSS NORTHERN UTAH TONIGHT AND
 SATURDAY THEN STALL. ANOTHER WEAK DISTURBANCE WILL AFFECT NORTHERN
 UTAH ON SUNDAY. 
 
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 .DISCUSSION...MID LEVEL RIDGE WHICH AS RESIDED ACROSS THE REGION THE 
 PAST COUPLE OF DAYS HAS SHIFTED EAST...AND IS NOW CENTERED ALONG THE 
 CENTRAL/NORTHERN ROCKIES. THIS IS DOWNSTREAM FROM SHORTWAVE TROUGH 
 NOW MOVING ONSHORE ACROSS THE PACIFIC NORTHWEST. SOUTHWESTERLY FLOW 
 BETWEEN THESE TWO FEATURES WILL INCREASE ACROSS MUCH OF THE FORECAST 
 AREA THIS AFTERNOON...RESULTING IN WARM AND WINDY CONDITIONS. 
 
 MID LEVEL MOISTURE...PRIMARILY CONFINED ABOVE 550MB BASED ON 
 REGIONAL 12Z SOUNDINGS...HAS SPREAD ACROSS MUCH OF THE GREAT BASIN 
 THIS MORNING. ALREADY SEEING CONSIDERABLE VIRGA ACROSS MUCH OF THE 
 FORECAST AREA...AND WITH AFTERNOON HEATING/DEEP MIXING DRY 
 MICROBURSTS APPEAR LIKELY THIS AFTERNOON. GIVEN HEIGHT OF MOISTURE 
 LAYER....SUSPECT INSTABILITY WILL BE SUPPORTIVE OF ONLY ISOLATED 
 LIGHTNING STRIKES DESPITE LIKELIHOOD OF WIDESPREAD VIRGA. 
 
 SURFACE FRONT ASSOCIATED WITH AFOREMENTIONED TROUGH EXPECTED TO 
 REACH NORTHERN UT LATE THIS EVENING...THEN CONTINUE SOUTH THROUGH 
 NORTHERN UT OVERNIGHT BEFORE STALLING ACROSS CENTRAL UT SATURDAY. 
 LINGERING MOISTURE ACROSS THE EAST WILL SUPPORT A THREAT OF DIURNAL 
 CONVECTION...WHILE COOLER AIR ALOFT BEHIND THIS FRONT KNOCKS SEVERAL 
 DEGREES OFF MAX TEMPS ALONG THE WASATCH FRONT. 
 
 UPDATED EARLIER TO INCREASE CLOUD COVER ACROSS NORTHEASTERN CWA...AS 
 WELL AS INCREASE AFTERNOON WINDS ALONG THE WASATCH FRONT. OTHERWISE 
 GOING FORECAST APPEARS IN GOOD SHAPE.
 
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 .AVIATION...MOISTURE PLUME ACROSS NRN UTAH TODAY WILL RESULT IN 
 SCATTERED LIGHT SHOWERS/ISOLATED THUNDERSTORMS AFFECTING THE KSLC 
 TERMINAL TODAY. STRONG AND ERRATIC WINDS ARE POSSIBLE WITH ANY OF 
 THE SHOWERS/STORMS OVER OR NEAR THE TERMINAL. PREVAIL SURFACE WINDS 
 AWAY FROM SHOWERS/STORMS WILL BE OUT OF THE SOUTH...AND WILL BE ON 
 THE INCREASE THROUGH EARLY AFTERNOON.
 
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 .FIRE WEATHER...THE DOMINATE UPPER RIDGE ACROSS THE INTERIOR WEST 
 WILL HOLD FIRM TODAY. AN UPPER LEVEL TROUGH WILL MOVE EAST ACROSS 
 THE NRN ROCKIES TONIGHT/EARLY SATURDAY...FORCING THE UPPER RIDGE
 SE INTO THE SRN ROCKIES. WINDS WILL INCREASE AHEAD OF THE UPPER 
 TROUGH ACROSS WRN/SRN UTAH. ALREADY LOW RH VALUES COMBINED WITH 
 THESE WINDS WILL CREATE SEVERE FIRE WEATHER CONDITIONS INTO THIS 
 EVENING.
 
 THE MOISTURE PLUME THAT SPREAD NORTH ACROSS UTAH OVERNIGHT WILL 
 CREATE SCATTERED HIGH-BASED SHOWER/ISOLATED THUNDERSTORM ACTIVITY 
 TODAY. SPOTTY WETTING RAINS IN THE MOUNTAINS ABOUT ALL TO EXPECTED 
 AS THE SHOWERS/STORMS WILL BE OF A SHORT DURATION. DRIER AIR WILL 
 WORK INTO WRN UT SATURDAY...WITH PLENTY OF MOISTURE REMAINING OVER 
 ERN AND NRN PORTIONS OF THE STATE. THE DRIER AIR WILL PUNCH THROUGH 
 THE STATE SUNDAY...LEAVING ANY THUNDERSTORM ACTIVITY CONFINED TO THE 
 FAR NRN AND SRN EXTREMES OF UTAH.
 
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 .SLC WATCHES/WARNINGS/ADVISORIES...
 UT...RED FLAG WARNING FROM 11 AM FRIDAY TO 10 PM FRIDAY FOR UTZ420-
      UTZ422-UTZ423-UTZ424-UTZ433-UTZ434-UTZ435-UTZ436-UTZ437-
      UTZ439-UTZ440.
 
 WY...NONE.
 
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 $$
 
 WILENSKY/YOUNG
 
 FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
 HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)