Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 292303
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
503 PM MDT MON JUN 29 2015

.UPDATE...UPDATED FORECAST TO INCREASE POPS THIS EVENING. EXPECT
THAT WE ARE AT PEAK CONVECTIVE COVERAGE AT THIS HOUR...BEFORE
GRADUALLY DECAYING OVER THE NEXT SEVERAL HOURS. BULKED UP POPS
ACROSS CENTRAL UTAH...AND EXPANDED ISOLATED TO INCLUDE ALL OF
SOUTHERN UTAH. LOOKS QUIET FROM SLC NORTHWARD.

&&

.SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL REMAIN ANCHORED ACROSS
THE GREAT BASIN THROUGH THE WEEK. THE CENTER OF THE HIGH PRESSURE
WILL SHIFT TO THE FOUR CORNERS REGION THIS WEEKEND...ALLOWING
MOISTURE ALONG WITH MODESTLY COOLER TEMPERATURES TO MOVE INTO THE
REGION BY EARLY NEXT WEEK.

&&

.DISCUSSION....THE STRONG UPPER RIDGE CENTERED OVER THE GREAT
BASIN WILL REMAIN THE DOMINANT FEATURE THROUGH THE SHORT TERM
FORECAST PERIOD. A SHORTWAVE MOVING EAST ACROSS THE NORTHERN
ROCKIES ON TUESDAY WILL FLATTEN THE RIDGE A BIT...BUT WILL HAVE
LITTLE IMPACT ON SENSIBLE WEATHER. WILL LOWER TEMPS A FEW DEGREES
FOR TUESDAY...WITH STILL SOLID DYNAMIC SUBSIDENCE LIMITING MOST
CONVECTION TO THE HIGHER TERRAIN DURING THE AFTERNOON/EARLY
EVENING HOURS.

A SECONDARY SHORTWAVE DIGGING SOUTHEAST INTO THE NORTH PLAINS
STATES WILL FORCE THE RIDGE WEST INTO THE WESTERN GREAT BASIN
WEDNESDAY NIGHT THROUGH THURSDAY. A DRIER AND STILL VERY WARM
NORTH-NORTHWEST FLOW ON THE EAST SIDE OF THE RIDGE WILL KEEP TEMPS
WELL ABOVE NORMAL WITH LIMITED HIGH TERRAIN SHOWERS/THUNDERSTORMS
DURING THE AFTERNOON/EARLY EVENING HOURS.

DRIER AIRMASS BECOMES WELL ESTABLISHED OVER THE CWA BY FRIDAY
WITH MODELS INDICATING PWS IN THE 0.25-0.5 INCH RANGE. THE DRY AND
STABLE AIRMASS IS EXPECTED TO LIMITED ANY AFTERNOON/EARLY EVENING
CONVECTION TO THE HIGHER TERRAIN.

THE RIDGE AXIS IS PROGGED TO SHIFT EAST OVER THE WEEKEND. THIS WILL
ALLOW SOME MOISTURE TO SLOWLY MOVE BACK IN AS TEMPERATURES WARM.
THUS...AFTERNOON CONVECTION IS ONCE AGAIN POSSIBLE OVER THE HIGHER
TERRAIN. BY SUNDAY...THE RIDGE AXIS WILL BE EAST OF THE AREA. THE
SOUTHERLY FLOW THAT DEVELOPS WILL ALLOW TROPICAL MOISTURE TO BE
DRAWN INTO THE AREA. GFS IS STILL SLOWER WITH THE ARRIVAL OF
MOISTURE COMPARED TO THE GFS...MOVING THE BRUNT OF THE MOISTURE IN
EARLY MONDAY AS OPPOSED TO DURING THE DAY SUNDAY IN THE EC. CURRENT
POP TREND IN THE FORECAST COVERS THE INCREASE IN MOISTURE WELL WITH
ABOVE CLIMO POPS FOR MOST LOCATIONS BY SUNDAY AND EVEN HIGHER ON
MONDAY. THE INCREASE IN MOISTURE WILL ALSO RESULT IN A DOWNWARD
TREND IN TEMPERATURES FOR MONDAY.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT THE KSLC TERMINAL THROUGH
THE TAF PERIOD. NORTHWEST WINDS THIS AFTERNOON ARE EXPECTED TO
SWITCH TO THE SOUTHEAST BETWEEN 0200 AND 0400 UTC. HOWEVER...THERE
IS A 20 PERCENT CHANCE THAT THE WIND SHIFT WILL HOLD OFF UNTIL AFTER
0400 UTC.

&&

.FIRE WEATHER...THE UPPER RIDGE CENTERED OVER THE GREAT BASIN WILL
MAINTAIN THE HOT/DRY CONDITIONS IN THE VALLEYS...WITH ISOLATED
CONVECTION GENERATING MINIMAL RAIN AND LIGHTNING/ERRATIC WINDS
OVER THE HIGH TERRAIN THROUGH THE BALANCE OF THE WEEK.

A TRANSITION TO MORE ACTIVE CONVECTION WILL BEGIN THIS WEEKEND AS
THE CENTER OF THE UPPER RIDGE SHIFTS TOWARDS THE FOUR CORNERS
REGION. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL OVER THE
WEEKEND WITH AN INCREASE IN HUMIDITIES AND CONVECTION DURING THE
LATTER HALF OF THE WEEKEND. BY EARLY NEXT WEEK MORE SEASONAL
TEMPERATURES...HIGHER RH VALUES AND AN INCREASING AREAL COVERAGE
OF SHOWERS/STORMS IS EXPECTED AS A MOIST SOUTHERLY FLOW DEVELOPS
ACROSS THE GREAT BASIN FOR THE FIRST HALF OF THE WEEK.

&&

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

$$

PUBLIC...ROGOWSKI/TRAPHAGAN
FIRE WEATHER...CONGER
AVIATION...GRAHAM

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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