013
FXUS65 KSLC 091507
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
907 AM MDT WED JUL 9 2025
UPDATE
UPDATED FOR AVIATION DISCUSSION.
SYNOPSIS
HOT AND MOSTLY DRY CONDITIONS WILL PERSIST OVER UTAH
AND SOUTHWEST WYOMING TODAY, WITH A FEW HIGH BASED SHOWERS
DEVELOPING OVER THE HIGHER TERRAIN THIS AFTERNOON. A WEAKENING
STORM SYSTEM WILL CROSS NORTHERN UTAH AND SOUTHWEST WYOMING
TONIGHT INTO EARLY THURSDAY, BRINGING TEMPERATURES BACK CLOSER TO
SEASONAL NORMALS. HIGH PRESSURE WILL REBUILD BY THE WEEKEND,
BRINGING ANOTHER WARMING TREND.
SHORT TERM (THROUGH 12Z/6AM FRIDAY)
HIGH PRESSURE REMAINS
PARKED OVER THE DESERT SOUTHWEST THIS MORNING AS THE LOW THAT HAS
BEEN HOVERING OFF THE PACIFIC COAST OVER THE LAST FEW DAYS MOVES
ONSHORE OVER NORTHERN CALIFORNIA. UTAH AND SOUTHWEST WYOMING
REMAIN UNDER A WARM SOUTHWEST FLOW ALOFT, WITH HIGH TEMPERATURES
AGAIN EXPECTED TO AVERAGE AROUND 10F ABOVE SEASONAL NORMALS THIS
AFTERNOON.
THE TROUGH IS ON TRACK TO MOVE INTO THE GREAT BASIN THIS AFTERNOON
AS IT WEAKENS. THE TRAJECTORY OF THE SYSTEM WILL MOVE THE
PERSISTENT DRY SLOT AWAY FROM THE AREA, ALLOWING SOME MID AND HIGH
LEVEL MOISTURE TO START TO ADVECT IN, ENOUGH FOR A FEW HIGH BASED
SHOWERS TO DEVELOP OVER THE HIGHER TERRAIN THIS AFTERNOON AND INTO
THE EARLY EVENING. AS THE LOW MOVES CLOSER, THE FLOW ALOFT WILL
ALSO INCREASE, RESULTING IN SOME BREEZY CONDITIONS, PARTICULARLY
OVER WESTERN UTAH. THIS WILL COMBINE WITH THE HOT AND DRY AIRMASS
TO PRODUCE AREAS OF CRITICAL FIRE WEATHER CONDITIONS OVER PORTIONS
OF SOUTHERN AND WESTERN UTAH, WHERE A RED FLAG WARNING IS IN
EFFECT. SEE THE FIRE WEATHER SECTION OF THE AFD FOR MORE DETAILS.
GUIDANCE IS IN GOOD AGREEMENT THAT THE WEAKENING TROUGH WILL TRACK
ACROSS NORTHERN UTAH AND SOUTHWEST WYOMING TONIGHT INTO EARLY
TOMORROW. GIVEN THE WEAKENED STATE OF THE SYSTEM AND OVERALL LACK
OF MOISTURE AND DYNAMICS, ASSOCIATED SHOWER ACTIVITY WILL BE
MINIMAL AT BEST. THE SYSTEM WILL, HOWEVER, BRING A COLD FRONT
THROUGH, BRINGING A NOTICEABLE CHANGE IN TEMPERATURES FOR
THURSDAY, PARTICULARLY FOR NORTHERN PORTIONS OF THE FORECAST AREA.
THOSE AREAS WILL SEE AROUND 10F OF COOLING, BRINGING MAXES BACK
AROUND TO NEAR SEASONAL NORMALS. COOLING OVER SOUTHERN UTAH WILL
BE MORE LIMITED, A FEW DEGREES AT BEST.
LONG TERM (AFTER 12Z/6AM FRIDAY)
THE PERIOD STARTS WITH DRY
WESTERLY/NORTHWESTERLY FLOW ALOFT AND SURFACE TEMPERATURES A FEW
DEGREES BELOW NORMAL ACROSS NORTHERN UTAH/SW WYOMING. HOWEVER,
ACROSS SOUTHERN UTAH TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL
GIVEN THE PROXIMITY TO A RIDGE CENTERED OVER SOUTHERN CALIFORNIA.
HIGH PRESSURE WILL REMAIN CENTERED OVER CALIFORNIA THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK. THIS WILL KEEP CONDITIONS DRY WITH
GRADUALLY WARMING TEMPERATURES ACROSS NORTHERN UTAH WHILE SOUTHERN
UTAH KEEPS TEMPERATURES BETWEEN 105-108F.
GUIDANCE IS STARTING TO HINT AT A BREAKDOWN IN THE RIDGE AND
POTENTIALLY RE-ORIENTING FURTHER TO THE EAST TO ALLOW FOR A RETURN
OF SOME MOISTURE BY THE MIDDLE TO THE END OF NEXT WEEK. THE SIGNAL
IS STILL PRETTY WEAK WHICH WOULD LIKELY LIMIT THE MAGNITUDE AND
EXTENT OF THE MOISTURE TO THE TERRAIN OF SOUTHERN AND CENTRAL UTAH.
HOWEVER, THE LATEST CPC FORECAST DOES HAVE A BETTER MONSOON SIGNAL
IN THE JULY 16-22 TIME PERIOD ACROSS ARIZONA AND SOUTHERN UTAH WITH
LOWER PROBABILITIES (BUT STILL FAVORING WETTER) THE FURTHER NORTH
YOU GO.
AVIATION...KSLC
PREDOMINANTLY VFR CONDITIONS WILL CONTINUE
TODAY/TONIGHT, THOUGH WITH A COMPLICATED AND LOWER-CONFIDENCE WIND
FORECAST. SOUTHERLY WIND GUSTS WILL INCREASE THIS MORNING, WITH A
LOW CHANCE (10-40%) OF A LAKE BREEZE SNEAKING IN BETWEEN 19 AND 23Z
WHICH WOULD TURN WINDS NORTHWESTERLY. BETWEEN 22Z-01Z, EXPECTING
DEEPER CUMULUS AND VICINITY SHOWERS TO FORM WITH A THREAT OF OUTFLOW
WINDS AND A LIKELY SWITCH TO NORTHWEST WINDS. THERE IS A VERY LOW
CHANCE (<20%) OF CONTINUED SOUTHERLY WINDS INTO THE EVENING. A COLD
FRONT WILL PUSH THROUGH BETWEEN 3 AND 6Z TURNING WINDS TO CONSISTENT
NORTHWESTERLY AND CLEARING SKIES FOR THE REST OF THE NIGHT.
REST OF UTAH AND SOUTHWEST WYOMING
VFR CONDITIONS WILL PERSIST
FOR THE ENTIRE AIRSPACE THROUGHOUT THE PERIOD. SOUTHERLY WINDS WILL
BE GUSTY FOR MOST LOCATIONS DURING THE DAY AHEAD OF A MOSTLY DRY
FRONT. THIS FRONT WILL PUSH THROUGH THE NORTHERN AIRSPACE DURING THE
AFTERNOON/EVENING WITH ISOLATED (~20% CHANCE) HIGH-BASED CONVECTION
ACROSS THE NORTH AND EAST PORTIONS OF THE AREA. THE PRIMARY IMPACT
FROM THESE WILL BE GUSTY OUTFLOW WINDS WITH VERY LITTLE RAIN
POSSIBLE.
FIRE WEATHER
HIGH PRESSURE CENTERED OVER THE DESERT SOUTHWEST
WILL MAINTAIN A HOT AND DRY AIRMASS OVER UTAH TODAY. AS A PACIFIC
STORM SYSTEM MOVES INTO THE GREAT BASIN DURING THE DAY, SOUTHWEST
WINDS WILL INCREASE, PRODUCING AREAS OF CRITICAL FIRE WEATHER
CONDITIONS DURING THE AFTERNOON AND EVENING ACROSS SOUTHERN AND
WESTERN UTAH. WITH A SMALL INCREASE IN MID-LEVEL MOISTURE WITH AND
AHEAD OF THE TROUGH, ANTICIPATING A FEW HIGH BASED STORMS FOCUSED
OVER THE HIGHER TERRAIN THIS AFTERNOON AND EVENING, WITH GUSTY
WINDS AND ISOLATED DRY LIGHTNING THE MAIN THREATS WITH ANY STORMS
THAT DEVELOP. THE TROUGH WILL PASS ACROSS NORTHERN UTAH IN A
WEAKENED STATE LATE WEDNESDAY INTO EARLY THURSDAY, BRINGING MORE
SEASONABLE TEMPERATURES BEHIND IT BUT LITTLE IN THE WAY OF
PRECIPITATION. HIGH PRESSURE WILL THEN REBUILD FOR THE UPCOMING
WEEKEND, BRINGING CONTINUED DRY CONDITIONS AND ANOTHER WARMING
TREND.
SLC WATCHES/WARNINGS/ADVISORIES
UT...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR UTZ492-493-
495>498.
WY...NONE.
SHORT TERM...TRAPHAGAN
LONG TERM...MAHAN
AVIATION...VAN CLEAVE
FIRE WEATHER...TRAPHAGAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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