Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 242142
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
342 PM MDT SUN MAY 24 2015

.SYNOPSIS...HIGH PRESSURE ALOFT WILL SLIDE EAST ACROSS UTAH LATE
TONIGHT THROUGH TUESDAY. A NEW PACIFIC STORM SYSTEM WILL SETTLE
INTO THE PACIFIC NORTHWEST THROUGH THE NORTHERN ROCKIES ON
TUESDAY. THIS STORM SYSTEM WILL IMPACT MAINLY NORTHERN UTAH
MIDWEEK.

&&

.SHORT TERM (THROUGH 06Z THURSDAY)...THE UPPER LOW CURRENTLY OVER
SOUTHERN WYOMING WILL CONTINUE SLOWLY EAST INTO THE CENTRAL PLAINS
STATES BY EARLY MONDAY. BEHIND THIS LOW THE COOL AND MOIST
AIRMASS OVER THE GREAT BASIN HAS SPAWNED ISOLATED TO SCATTERED
CONVECTION ACROSS UTAH AND SOUTHWEST WYOMING THIS AFTERNOON.

WEAK SHORTWAVES ROTATING SOUTH BEHIND THE UPPER LOW THE LIKELY
DRIVING FORCE BEHIND THE BETTER ORGANIZED CONVECTION ACROSS
EXTREME SOUTHWEST THROUGH SOUTH-CENTRAL UTAH...AND OVER NORTHEAST
NEVADA. THE SHORTWAVE ACROSS NORTHEAST NEVADA THE MORE
INTERESTING OF THE TWO BASED ON THE COOLING CONVECTIVE CLOUD TOP
AND THE CIRCULATION EVIDENT IN THE WATER VAPOR IMAGERY. SUSPECT
THIS FEATURE WILL HAVE ENOUGH SHEAR AND DYNAMIC LIFT TO SUPPORT
HEAVY SHOWERS AND SMALL HAIL AT LEAST THROUGH MID-EVENING.
SOMEWHAT CONCERNED ABOUT EVEN HEAVIER PRECIP AS THIS FEATURE HIT
THE HIGHER TERRAIN OVER SOUTHWEST UTAH LATE TONIGHT. SOME TERRAIN
ENHANCEMENT ALONG WITH STILL DECENT CONVECTIVE DEVELOPMENT COULD
LEAD TO POCKETS OF FAIRLY HEAVY PRECIP ALONG THE I-15 CORRIDOR
AND IN THE MOUNTAINS TO THE EAST OVERNIGHT.

A LOW-AMPLITUDE SHORTWAVE RIDGE MOVING EAST INTO THE GREAT BASIN
FOR LATE TONIGHT/TUESDAY. SUBSIDENCE ASSOCIATED WITH THIS FEATURE
SHOULD REDUCE CONVECTION MONDAY AFTERNOON/EVENING. ENOUGH RESIDUAL
MOISTURE WILL REMAIN THAT DIFFERENTIAL HEATING SHOULD GENERATE
PLENTY OF CONVECTIVE CLOUD COVER OVER THE HIGHER TERRAIN...WITH
SOME LOW TOPPED CONVECTION PRODUCING POCKETS OF BRIEF RAIN DURING
THE AFTERNOON AND EARLY EVENING HOURS.

THE UPPER LOW SETTLING INTO THE PACIFIC NORTHWEST/NORTHERN ROCKIES
TUESDAY WILL PRIMARILY IMPACT THE NORTHERN HALF OF UTAH MIDWEEK.
THE CYCLONIC WEST-SOUTHWEST FLOW ALOFT TOT HE SOUTH OF THE LOW
WILL USHER IN A SERIES OF FAST-MOVING SHORTWAVES ACROSS THE NORTH
LATE TUESDAY THROUGH WEDNESDAY EVENING. MOISTURE...THOUGH SOMEWHAT
REDUCED WHEN COMPARED TO THE PAST SEVERAL DAYS...SHOULD BE
SUFFICIENT TO GENERATE SCATTERED CONVECTION ASSOCIATED WITH THE
PASSING SHORTWAVES. DOWN SOUTH A WARMING TREND WILL BRING TEMPS
BACK TO SEASONAL NORMS WITH LITTLE THREAT FOR PRECIP.



.LONG TERM (AFTER 06Z THURSDAY)...THE EC AND GFS ARE TRENDING A
LITTLE STRONGER WITH THE TROUGH MOVING THROUGH THURSDAY. THE 300MB
JET DIVERGENCE IS LOCATED OVER NORTHERN UTAH 12Z THURSDAY ALONG WITH
SOME COLD ADVECTION BETWEEN 700 AND 500 MB. THE TROUGH SHARPENS AS
IT MOVES ACROSS UTAH AND BECAUSE THIS APPEARS TO BE THE CABOOSE OF
SHORTWAVES THEY TYPICALLY ARE STRONGER THAN FORECAST. THEREFORE HAVE
BOOSTED POPS BETWEEN 06Z THURSDAY AND 06Z FRIDAY ACROSS MAINLY
NORTHERN UTAH BUT SOME IN CENTRAL AND SOUTHERN UTAH AS WELL. HAVE
LOWERED TEMPS JUST A TAD AS SOME BREAKS OF SUNSHINE LATER IN THE
AFTERNOON COULD WARM IT BACK TO NEAR 70 DEGREES AT SLC WHICH IS
STILL 5 DEGREES BELOW NORMAL.

THERE IS STILL A 500 MB CIRCULATION OVER EASTERN UTAH WELL INTO
FRIDAY SO HAVE KEPT SOME POPS IN OVER THE HIGHER TERRAIN AND THE
EASTERN PORTIONS OF THE CWA. HAVE REMOVED ALL POPS FOR THE WEEKEND
EXCEPT FOR ISOLATED THUNDERSTORMS OVER THE UINTAS SATURDAY AFTERNOON.

THE EC AND GFS SHOW A RIDGE OVER THE REGION THIS WEEKEND WHICH WILL
BE THE FIRST RIDGE OF ANY SIGNIFICANCE THIS MAY. WARMING TREND
BEGINS FRIDAY WITH ABOUT 5 DEGREES WARMING PER DAY THROUGH THE
WEEKEND. WILL LIKELY SEE THE WARMEST TEMPERATURES OF THE SEASON BY
SUNDAY ACROSS THE CWA.

&&

.AVIATION...NORTH TO NORTHWEST WINDS WILL CONTINUE AT THE SLC
TERMINAL THROUGH 03-05Z. SHOWERS ARE POSSIBLE IN THE VICINITY OF THE
TERMINAL THROUGH THE EVENING...AND ANY SHOWERS IN THE AREA COULD
CAUSE GUSTY AND ERRATIC WINDS AND OCCASIONAL CEILINGS AT ABOUT 4000-
5000 FEET.

&&

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

$$

SHORT TERM...CONGER
LONG TERM...STRUTHWOLF
AVIATION...KRUSE

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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