Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 232128
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
328 PM MDT SAT MAY 23 2015

.SYNOPSIS...THE UPPER LEVEL LOW PRESSURE SYSTEM OVER EXTREME
EASTERN UTAH WILL CONTINUE EAST INTO THE CENTRAL ROCKIES TONIGHT.
WEAK HIGH PRESSURE ALOFT WILL SETTLE OVER THE STATE MONDAY...
FOLLOWED BY THE NEXT STORM SYSTEM IMPACTING MAINLY NORTHERN UTAH
MIDWEEK.

&&

.SHORT TERM (THROUGH 06 WEDNESDAY)...THE UPPER LOW ALONG THE
UTAH/COLORADO AT MID-AFTERNOON WILL CONTINUE ON A SLOW EASTWARD
TRACK INTO THE CENTRAL ROCKIES OVERNIGHT. SCATTERED SHOWERS AND
THUNDERSTORMS HAVE REMAINED IN CLOSE PROXIMITY TO THE LOW CENTER
AND THE COLD POOL ALOFT AND ACROSS THE EASTERN HALF OF THE
FORECAST AREA. THIS ACTIVITY SHOULD GRADUALLY WIND DOWN AND
SHIFT INTO THE EASTERN EXTREMES OF UTAH LATER TONIGHT.

ORGANIZED STRATIFORM PRECIP ALONG THE BACK SIDE OF THE UPPER LOW
WILL PERSIST ACROSS WEST-CENTRAL THROUGH SOUTHWEST UTAH THIS
EVENING. THE WARM ADVECTION CYCLONIC NORTHWEST FLOW ALOFT WILL
MAINTAIN FAIRLY STRONG UPWARD MOTIONS WITH WIDESPREAD PRECIP
EXPECTED THROUGH THE EVENING HOURS. THIS PRECIP WILL CONCENTRATE
OVER SOUTHWEST UTAH LATE TONIGHT...THEN EXIT OFF TO THE EAST WITH
THE UPPER LOW BY EARLY SUNDAY. TERRAIN ENHANCEMENT OF THE PRECIP
IS EXPECTED ACROSS THE SOUTHERN MOUNTAINS OVERNIGHT. SEVERAL
INCHES OF NEW SNOW ABOVE 8000 FEET IS EXPECTED...THOUGH TRAVEL
IMPACTS WILL REMAIN MINIMAL AND CONFINED TO THE HIGHER PASSES.

PLENTY OF RESIDUAL MOISTURE WILL REMAIN OVER UTAH IN THE WAKE OF
THE EXITING UPPER LOW FOR SUNDAY. CONVECTION SHOULD GET AN EARLY
START AGAIN SUNDAY MORNING...THOUGH WITH MODEST WARMING IN THE
MID-LEVELS THE THREAT OF DEEP CONVECTION SHOULD BE REDUCED. WILL
HAVE TO KEEP AN EYE ON WEAK SHORTWAVES TRAILING THE EXITING LOW.
ANY WEAK DYNAMIC SUPPORT PUSHING THROUGH DURING THE AFTERNOON
COULD ENHANCE CONVECTION ENOUGH TO PRODUCE SMALL HAIL/BRIEF HEAVY
RAIN INTO THE EVENING HOURS.

A WEAK SHORTWAVE RIDGE SLIDING EAST INTO THE GREAT BASIN MONDAY
SHOULD FURTHER REDUCE CONVECTIVE PRECIP DURING THE AFTERNOON AND
EARLY EVENING. SUSPECT THE MOUNTAINS WILL STILL BE PRONE TO
SCATTERED SHOWERS/ISOLATED STORMS...BUT DO NOT SEE ANY REAL THREAT
FOR HEAVY PRECIP AT THIS TIME. THE NEXT UPPER LOW SETTLING SOUTH
INTO THE PACIFIC NORTHWEST/NORTHERN ROCKIES ON MONDAY NIGHT WILL
GENERATE A CYCLONIC WEST-NORTHWEST ACROSS THE NORTHERN/CENTRAL
GREAT BASIN BY TUESDAY. EMBEDDED SHORTWAVES EJECTING OUT OF THE
UPPER LOW WILL OFFER UP THE CHANCE OF SHOWERS/STORMS TO PRIMARILY
NORTHERN UTAH HEADING INTO THE MIDWEEK PERIOD. TEMPS WILL ALSO
SHOW A WARMING TREND...WITH READING RETURNING TO LATE MAY NORMS
ACROSS MOST OF THE FORECAST AREA.

.LONG TERM (AFTER 06Z WEDNESDAY)...GLOBAL MODELS PRETTY CONSISTENT
BETWEEN THEM THAT A BAGGY TROUGH REMAINS OVER THE INTERMOUNTAIN
REGION WEDNESDAY THROUGH THURSDAY. THE 12Z EC IS WEAKER WITH THE
TROUGH THAN ITS 00Z RUN BUT IT NOW HAS A WEAK TROUGH MOVING ACROSS
SOUTHERN IDAHO AND NORTHERN UTAH WEDNESDAY AFTERNOON. INTERESTINGLY
ENOUGH THE 500 MB TEMPS ARE STILL COOLER ON THE GFS OVER NORTHERN
UTAH. IN EITHER CASE WITH A MOIST AIR MASS STILL IN PLACE IT WAS
WARRANTED TO INCREASE POPS A LITTLE FOR WEDNESDAY AFTERNOON.

THE EC AND GFS SHOW A SHARPER TROUGH SWINGING THROUGH UTAH AND SW
WYOMING THURSDAY AFTERNOON. HAVE INCREASED POPS A LITTLE BUT MAY
NEED MORE OF AN INCREASE AS THIS APPEARS TO BE THE CABOOSE OF
SHORTWAVES WHICH USUALLY SIGNALS IT BEING STRONGER THAN MODEL
FORECASTS.

HAVE RAISED TEMPS A FEW DEGREES FROM PREVIOUS FORECAST FOR WEDNESDAY
AS 700MB TEMPS WOULD SUPPORT TEMPS NEAR 75 AT SLC IF WELL MIXED. DID
NOT THINK THIS WOULD HAPPEN SO KEPT IT A COUPLE DEGREES BELOW THAT.
IT LOOKS LIKE TEMPS WILL BE A LITTLE COOLER THURSDAY WITH THAT
SHARPER TROUGH SO TEMPS WERE TRENDED DOWN A LITTLE.

FOR FRIDAY AND SATURDAY A RIDGE FINALLY MOVES INTO THE GREAT BASIN
AND TEMPERATURES WILL WARM TO THEIR HIGHEST LEVELS SO FAR IN MAY.
THE TREND OF DRYING THINGS OUT...ESPECIALLY ACROSS THE NORTH...WAS
SPED UP SOME WITH ISOLATED POPS OVER THE HIGHER TERRAIN OF
NORTHERN UT FRIDAY AND NO POPS BY SATURDAY.

&&

.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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