989
FXUS65 KSLC 192058
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
258 PM MDT FRI AUG 19 2022
SYNOPSIS
MONSOON MOISTURE WILL REMAIN IN PLACE ACROSS THE
REGION THROUGH SATURDAY. DRIER AIR WILL BUILD INTO THE STATE
SUNDAY INTO EARLY NEXT WEEK, GIVING A REPRIEVE FROM THE MONSOON,
WITH ANOTHER SURGE POSSIBLE MID TO LATE WEEK.
SHORT TERM (THROUGH 12Z/6AM SUNDAY)
EARLY AFTERNOON ANALYSIS
INDICATES AN INTERESTING PATTERN IN PLACE ACROSS UTAH AND SW
WYOMING. AN UPPER LOW IS PARKED NEAR THE ID/OR/NV BORDER REGION
WITH A TRAILING SHORTWAVE IN PLACE ACROSS CENTRAL UTAH. STEERING
FLOW IS OUT OF THE WEST-NORTHWEST ACROSS SOUTHWEST UTAH, OUT OF
THE SOUTH ACROSS SOUTHEAST UTAH, AND EASTERLY ACROSS NORTHEAST
UTAH AND SOUTHWEST WYOMING. NEARLY NULL/ZERO FLOW IS IN PLACE
FROM NW UTAH SOUTHEAST INTO CENTRAL UTAH -- A COMPLEX SETUP
INDEED. AN AREA OF SHOWERS IS DRAPED ALONG THIS NULL FLOW REGION,
COINCIDENT WITH THE AREA OF GREATEST MID-LEVEL ASCENT. ON EITHER
SIDE OF THE CLOUD SHIELD, PLENTIFUL SUNSHINE IS IN PLACE ACROSS
BOTH SW UTAH AND NE UTAH AND SW WYOMING, LEADING TO GRADUAL
DESTABILIZATION PER SATELLITE AND MESOANANLYSIS. DIFFERENTIAL
HEATING BOUNDARIES ARE SETTING UP ON EITHER SIDE OF THIS CLOUD
SHIELD. MEANWHILE, AN AXIS OF >1" PWAT IS IN PLACE ACROSS
SOUTHERN UTAH, AND EXTENDS NORTHWARD TO INCLUDE NW UTAH AND THE
WASATCH FRONT. FINALLY, UPPER DIFFLUENCE IS MAXIMIZED ACROSS
NORTHERN UTAH, WITHIN THE DEFORMATION REGION ASSOCIATED WITH THE
UPPER LOW. YOU MIGHT WONDER...HOW MIGHT THIS COMPLICATED SETUP
EVOLVE OVER THE REST OF THE AFTERNOON?
WE'VE ALREADY SEEN THUNDERSTORMS CONTAINING HEAVY RAINFALL OVER
ZION NP AND MORE RECENTLY NEAR HILDALE. CAMS SUGGEST THIS ACTIVITY
WILL CONTINUE TO SLOWLY TRACK SOUTH AND EAST OVER THE REMAINDER OF
THE AFTERNOON WITH AN ATTENDANT HEAVY RAINFALL AND FLASH FLOOD
THREAT FOR NORMALLY DRY WASHES, SLICKROCK, SLOT CANYONS AND OTHER
FLOOD-PRONE AREAS. MEANWHILE, CAMS ARE IN EXCELLENT AGREEMENT IN
DEVELOPING A CLUSTER OF SHOWER AND THUNDERSTORMS ALONG/EAST OF THE
WASTACH, ULTIMATELY TRACKING THIS ACTIVITY WESTWARD ACROSS THE
WASATCH FRONT BETWEEN 3PM-7PM. THIS ACTIVITY WILL BE CAPABLE OF
PRODUCING GUSTY OUTFLOW WINDS (FROM AN ATYPICAL EASTERLY
DIRECTION) AS WELL AS HEAVY RAINFALL WHICH MAY LEAD TO SOME
URBAN/SMALL STREAM FLOODING. AS WE HEAD THROUGH THE EVENING,
HEAVIEST CONVECTION WILL GRADUALLY DIMINISH, ESPECIALLY ACROSS
SOUTHERN UTAH WHERE ASCENT IS LESS AND A MID-LEVEL DRY SLOT WILL
TRY AND NUDGE INTO THIS AREA. FARTHER NORTH, AN AREA OF SHOWERS IS
EXPECTED TO CONTINUE FOR MUCH OF THE NIGHT IN THE
DIFFLUENT/DEFORMATION AXIS ASSOCIATED WITH THE APPROACHING UPPER
LOW. AREAS MOST FAVORED FOR NOCTURNAL SHOWERS INCLUDES NORTHERN
UTAH, NE UTAH AND EASTERN UTAH. MOST OF THIS ACTIVITY IS EXPECTED
TO REMAIN ON THE LIGHT TO OCCASIONALLY MODERATE SIDE.
ON SATURDAY, THE AFOREMENTIONED UPPER LOW IS FORECAST TO MEANDER
EASTWARD ACROSS NORTHERN UTAH, BECOMING CENTERED NEAR PROVO. THIS
LOW WILL ACT TO INCREASE LAPSE RATES AND LOWER LCLS. WIDESPREAD
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AFTERNOON
AS A RESULT, WITH COVERAGE MAXIMIZED OVER NORTHERN AND CENTRAL
UTAH, ESPECIALLY ALONG/EAST OF I-15. THIS ACTIVITY ALSO HAS THE
POTENTIAL TO PROMOTE LOCALIZED FLOODING CONCERNS AS COPIOUS LOW TO
MID-LEVEL MOISTURE WILL REMAIN IN PLACE. SIMILAR TO THIS EVENING,
ACTIVITY IS EXPECTED TO GRADUALLY WANE THROUGH THE EVENING.
LONG TERM (AFTER 12Z/6AM SUNDAY)
ON SUNDAY INTO MONDAY, AN
UPPER LEVEL TROUGH IS FORECAST TO SWING EASTWARD ACROSS THE
PACIFIC NORTHWEST AND NORTHERN ROCKIES. AT THE SAME TIME, A RIDGE
OF HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE GREAT BASIN. THIS
PROCESS WILL ACT TO SHIFT THE AXIS OF MONSOONAL MOISTURE OFF TO
THE EAST, INITIATING A DRYING TREND ACROSS THE REGION. HOWEVER,
ENOUGH LOW-LEVEL MOISTURE WILL LINGER FOR AREAS GENERALLY
ALONG/EAST OF I-15 TO SUPPORT ADDITIONAL SHOWER/THUNDERSTORM
ACTIVITY WITH AN ISOLATED HEAVY RAINFALL THREAT. THE DRYING TREND
WILL CONTINUE MONDAY WITH SHOWERS/THUNDERSTORMS EXPECTED TO BE
LIMITED TO MAINLY HIGH TERRAIN AREAS. CONTINUED DRYING ON TUESDAY
SUGGESTS LITTLE TO NO PRECIPITATION POTENTIAL. WITH THIS DRYING
TREND, A WARMING TREND IS EXPECTED AS WELL.
FOR THE MIDDLE TO LATER HALF OF NEXT WEEK, ENSEMBLES AND
DETERMINISTIC GUIDANCE IS IN REASONABLE AGREEMENT IN THEIR
RELATIVE DEPICTIONS OF MONSOONAL MOISTURE GRADUALLY RETURNING TO
THE AREA. ENOUGH MOISTURE APPEARS TO BE IN PLACE BY WEDNESDAY TO
SUPPORT MAINLY HIGH TERRAIN SHOWERS/THUNDERSTORMS -- WITH A FEW
POTENTIALLY SNEAKING INTO SOUTHWEST UTAH AS WELL. IT DOES APPEAR
THAT WIDESPREAD SHOWERS AND THUNDERSTORMS RETURN BY THURSDAY AND
FRIDAY OF NEXT WEEK, ALTHOUGH THE DEPTH OF MOISTURE REMAINS
UNCERTAIN AT THIS POINT. JUST OVER HALF OF THE SOLUTION SPACE
DEPICTS QPF ABOVE THE ENSEMBLE MEAN, AND THIS SUPPORTS THE BROAD
POP COVERAGE CURRENTLY IN OUR OFFICIAL FORECAST.
AVIATION...KSLC
PREDOMINANTLY VFR CONDITIONS ARE EXPECTED FOR
KSLC. DRY CONDITIONS TO START FOLLOWED BY AN INCREASED CHANCE FOR
SHOWERS AND THUNDERSTORMS AROUND 22Z AND LASTING UNTIL AROUND 01Z.
GUSTY AND ERRATIC OUTFLOW WINDS WILL BE POSSIBLE DURING THIS TIME.
PRECIPITATION CHANCES WILL BE ON AND OFF OVERNIGHT AND INTO THE DAY
TOMORROW. THERE IS CURRENTLY A BOUNDARY OVER THE AIRFIELD WITH
SOUTHERLY WINDS ON THE SOUTH SIDE AND WESTERLY WINDS ON THE NORTH
SIDE THAT WILL REMAIN IN PLACE UNTIL THE EASTERLY OUTFLOW WINDS
ARRIVE WITH SHOWERS AND STORMS THAT ARE STILL IN THE FORECAST. DROPS
IN VISIBILITY OR LOWER CLOUD BASES WILL BE POSSIBLE WITH THESE
STORMS.
REST OF UTAH AND SOUTHWEST WYOMING
PREDOMINANTLY VFR
CONDITIONS EXPECTED DURING THE PERIOD. SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE CWA WILL CONTINUE FOR THE REMAINDER OF THE
DAY. MVFR CONDITIONS WILL BE POSSIBLE WHEN ONE OF THESE
THUNDERSTORMS OR SHOWERS ARE NEARBY OR OVERHEAD. OTHER THAN GUSTY
AND ERRATIC OUTFLOW WINDS THAT COULD ACCOMPANY THESE SHOWERS AND
STORMS WINDS WILL BE DIURNALLY DRIVEN.
FIRE WEATHER
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE FORECAST
ACROSS MOST OF THE STATE THIS AFTERNOON AND EARLY EVENING AS WELL AS
SATURDAY, WITH THE BULK OF THE PRECIPITATION SHIFTING ACROSS
NORTHERN UTAH BY SATURDAY AFTERNOON. THIS WILL OCCUR AS AN AREA OF
LOW PRESSURE DRIFTS EASTWARD DIRECTLY ACROSS NORTHERN UTAH DURING
THE DAY SATURDAY. A DRYING TREND WILL THEN BEGIN TO BUILD INTO
THE REGION SUNDAY. AS A RESULT, AFTERNOON SHOWERS/THUNDERSTORMS
WILL BECOME CONFINED TO AREAS MAINLY ALONG/EAST OF I-15. THE
DRYING TREND WILL CONTINUE ON MONDAY AS ANOTHER AREA OF LOW
PRESSURE SLIDES ACROSS THE NORTHERN ROCKIES WHILE A RIDGE OF HIGH
PRESSURE BUILDS ACROSS THE STATE. THIS WILL CAUSE AFTERNOON/EARLY
EVENING SHOWER AND THUNDERSTORM COVERAGE WILL SHRINK TO MAINLY
HIGH TERRAIN AREAS BY MONDAY.
MAINLY DRY CONDITIONS ARE EXPECTED TUESDAY. A WARMING TREND WILL
ACCOMPANY THE DRYING TREND, AS TEMPERATURES RISE TO NEAR TO JUST
BELOW NORMAL SATURDAY TO NEAR TO JUST ABOVE NORMAL BY TUESDAY.
MONSOONAL MOISTURE IS THEN EXPECTED TO GRADUALLY RETURN TO THE
STATE BY THE MIDDLE TO LATER PORTION OF NEXT WEEK WITH SHOWER AND
THUNDERSTORM CHANCES INCREASING ALONG WITH HUMIDITY.
SLC WATCHES/WARNINGS/ADVISORIES
UT...FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR UTZ124>128.
WY...NONE.
ADESMET/CECAVA
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