Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 282234
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
434 PM MDT SUN JUN 28 2015

.SYNOPSIS...HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE REGION
THROUGH THE EARLY PART OF THE WEEK. THE UPPER LEVEL HIGH WILL
SHIFT WESTWARD AFTER MIDWEEK BRINGING A DRIER NORTHERLY FLOW TO
THE AREA. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE
WEEK.

&&

.SHORT TERM (UNTIL 06Z WEDNESDAY)...STRONG UPPER LEVEL RIDGE REMAINS
FIRMLY ENTRENCHED OVER THE GREAT BASIN THIS AFTERNOON. WITH 700
HPA TEMPERATURES OF +18 TO +20 DEGREES C OVER UTAH THE RESULT IS
ANOTHER HOT DAY ACROSS THE STATE. DESPITE LARGE SCALE SUBSIDENCE
BENEATH THE UPPER LEVEL RIDGE...FORCING ASSOCIATED WITH TERRAIN
CIRCULATIONS ...PRECIPITABLE WATER VALUES AROUND .75" AND SBCAPE
OF 500+ J/KG OVER THE ELEVATED TERRAIN...ISOLATED CONVECTION HAS
DEVELOPED OVER THE HIGH TERRAIN WITH THE GREATEST COVERAGE OVER THE
SOUTHERN MOUNTAINS. THERE IS ENOUGH INSTABILITY IN PLACE OVER THE
VALLEYS OF SOUTHWEST UTAH THAT EASTERLY FLOW ALONG THE SOUTHERN
PERIPHERY OF THE UPPER LEVEL HIGH IS ALLOWING SOME STORMS TO
PROPAGATE OVER VALLEYS IN SOUTHWEST UTAH...AS SHOWN BY THE HRRR
EARLIER TODAY. PRIMARY THREAT WITH THESE STORMS WOULD BE STRONG
GUSTY WINDS WITH SURFACE-BASED DEWPOINT DEPRESSIONS OF 50+
DEGREES F ACROSS THE STATE. ANTICIPATE THAT CONVECTION WILL
QUICKLY DIMINISH AFTER SUNSET AGAIN THIS EVENING.

THE UPPER LEVEL RIDGE REMAINS SOLIDLY IN PLACE ON MONDAY WITH 500
HPA HEIGHT AND 700 HPA TEMPERATURE ANOMALIES OF 1-2 STANDARD
DEVIATIONS ABOVE NORMAL. ANTICIPATE ANOTHER HOT DAY WITH HIGHS
SIMILAR TO THIS AFTERNOONS. SO...ANOTHER 100+ DEGREE F DAY ALONG
THE WASATCH FRONT. ALSO...ANTICIPATE A SIMILAR EVOLUTION WITH
AFTERNOON EVENING CONVECTION. THAT IS...ISOLATED STORMS DEVELOPING
OVER THE HIGH TERRAIN PRETTY MUCH STATEWIDE AND THEN SOME STORMS
DRIFTING WEST OFF OF THE TERRAIN INTO UTAHS SOUTHWEST VALLEYS.

ON TUESDAY...UPPER LEVEL WAVE CRESTS THE RIDGE AND MOVES THROUGH
THE NORTHERN INTERMOUNTAIN REGION. THIS FLATTENS THE RIDGE AND
ALLOWS MOISTURE THAT HAS BEEN CIRCULATING AROUND THE PERIPHERY OF
THE UPPER LEVEL HIGH TO SPREAD INTO UTAH. PRECIPITABLE WATER
VALUES RISE TO .80" TO 1" AND WITH INCREASED INSTABILITY IN PLACE
EXPECT MORE SCATTERED COVERAGE OF CONVECTION OVER THE HIGH
TERRAIN AND ISOLATED VALLEY CONVECTION STATEWIDE BY EVENING.
INITIAL PUSH OF SLIGHTLY COOLER AIR DRIFTS INTO FAR NORTHWEST
UTAH ON TUESDAY AND TEMPS DROP BACK A BIT ACROSS THE FAR
NORTHWEST. TEMPERATURES ARE AGAIN EXPECTED TO BE NEAR 100 DEGREES
F ALONG THE CENTRAL AND SOUTHERN WASATCH FRONT. THERE IS THE
POTENTIAL FOR THIS TO BE THE FOURTH CONSECUTIVE DAY OF 100+
DEGREES F AT SALT LAKE CITY WHICH HAS ONLY HAPPENED THREE TIMES IN
THE MONTH OF JUNE GOING BACK TO 1874.

.LONG TERM (AFTER 06Z WEDNESDAY)...MEDIUM RANGE MODELS ARE
CONSISTENT THROUGH THE LATTER PORTION OF THE WEEK IN RETROGRADING
THE MID LEVEL RIDGE WESTWARD INTO NV. THIS WILL ALLOW A LIGHT
NORTHWESTERLY FLOW ALOFT TO OVERSPREAD THE FORECAST AREA. THIS
FLOW WILL ADVECT DRIER AIR INTO NORTHERN UT SLOWLY SUPPRESSING THE
MOISTURE INTO SOUTHERN UT BY THURSDAY...AS WELL AS USHER IN SOME
SLIGHTLY COOLER AIR INTO THE FORECAST AREA. COOLER IN THIS CASE IS
A RELATIVE TERM...AS TEMPERATURES WILL REMAIN WELL ABOVE
NORMAL...HOWEVER SHOULD FALL SHORT OF THE CENTURY MARK ALONG THE
WASATCH FRONT.

DIFFERENCES BETWEEN THE GFS AND EC BECOME EVIDENT LATE IN THE WEEK
THROUGH NEXT WEEKEND...AS THE GFS MAINTAINS A STRONG MID LEVEL RIDGE
ACROSS THE REGION WHICH WOULD ALLOW FOR A WARMING TREND WITH HIGH
BASED MOISTURE QUICKLY RETURNING TO THE FORECAST AREA...WHILE THE EC
OFFERS A MUCH WEAKER RIDGING SOLUTION WITH A DRIER AND
SLIGHTLY COOLER NORTHWEST FLOW OVER MUCH OF THE EASTERN GREAT BASIN.
FOR NOW HAVE INCLUDED SLIGHT CHANCE POPS ACROSS FAVORED TERRAIN
AREAS WHILE MAINTAINING TEMPERATURES WELL ABOVE NORMAL. &&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT KSLC THROUGH THE TAF
PERIOD...WITH NORTHWEST WINDS SWITCHING BACK TO THE SOUTH AROUND
04Z.

&&

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

$$

SHORT TERM ...GRAHAM
LONG TERM...SEAMAN
AVIATION...SEAMAN

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)


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