268
FXUS65 KSLC 180418
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1018 PM MDT THU SEP 17 2026
KEY MESSAGES
- PERIODS OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TONIGHT INTO
FRIDAY, WITH THE BEST COVERAGE OVER NORTHERN UTAH AND SOUTHWEST
WYOMING. HEAVY RAIN, GUSTY WINDS, AND HAIL WILL BE THE PRIMARILY
THREATS.
- A COLD FRONT WILL BRING DRIER CONDITIONS WITH MORE SEASONABLE
TEMPERATURES SATURDAY THROUGH THE REMAINDER OF THE WEEKEND WITH
MOISTURE EXPECTED TO INCREASE AGAIN TO START THE WORK WEEK.
DISCUSSION
UTAH AND SOUTHWEST WYOMING REMAIN UNDER A MOIST,
UNSTABLE, AND BREEZY SOUTHERLY FLOW THIS EVENING IN BETWEEN HIGH
PRESSURE OVER THE CENTRAL UNITED STATES AND A BROAD LOW OVER THE
CALIFORNIA COAST. SATELLITE DERIVED PWS ARE IN THE 0.7 TO 1.0 INCH
RANGE ACROSS THE AREA, WITH THE HIGHEST VALUES OVER SOUTHEAST
UTAH. THE POSITION OF THE UPPER JET ON THE FRONT EDGE OF THE LOW
HAS BROUGHT THE BEST DIVERGENCE ROUGHLY TO NORTHEASTERN PORTIONS
OF THE AREA WITH A WEAK WAVE PROVIDING ADDITIONAL INSTABILITY,
PARTICULARLY TO AREAS NORTH OF I-70 AND EAST OF I-15, WITH ONE
STORM PRODUCING PING PONG BALL TO GOLF BALL SIZED HAIL IN THE CITY
OF MIDWAY.
OVERALL, THE CURRENT ROUND OF SHOWERS AND THUNDERSTORMS IS ON THE
DECREASE WITH A LACK OF DAYTIME HEATING, WITH JUST A FEW STRONGER
CELLS REMAINING. AS A RESULT, HAVE CANCELED THE GOING FLOOD WATCH
FOR FLASH FLOODING AS THE THREAT HAS ENDED. HOWEVER, AS THE LOW
SLIDES INTO NEVADA AND BRINGS AN INITIAL BOUNDARY THROUGH, SHOWERS
ARE EXPECTED TO LIGHT UP DURING THE EARLY MORNING, FOCUSED OVER
NORTHERN UTAH AND SOUTHWEST WYOMING. THE LOW IS THEN ON TRACK TO
GRAZE NORTHERN PORTIONS OF THE AREA AS IT MOVES BY THROUGH
SATURDAY. AS A RESULT, LOOKING AT THE MOST WIDESPREAD CONVECTION
TO BE ON FRIDAY AFTERNOON IN ASSOCIATION WITH THE MAIN TROUGH AND
ASSOCIATED COLD FRONT. CAMS CONTINUE TO INDICATE THE BEST COVERAGE
TO BE OVER NORTHERN PORTIONS OF THE AREA, BUT A FEW STORMS OVER
SOUTHERN UTAH COULD BRING AN ISOLATED THREAT OF FLASH FLOODING.
THE PASSAGE OF THE SYSTEM WILL ALSO HAVE A NOTICEABLE EFFECT ON
TEMPERATURES, WITH HIGHS FRIDAY INTO THE WEEKEND RUNNING 5-10F
BELOW SEASONAL NORMALS FOR NORTHERN UTAH AND SOUTHWEST WYOMING,
AND NEAR SEASONAL NORMALS FOR SOUTHERN UTAH. AS THE TROUGH EXITS,
THE FLOW ALOFT WILL MOVE TO A MORE WEST TO NORTHWESTERLY
DIRECTION, ALLOWING SOME DRIER AIR TO MOVE IN. WITH THE TROUGH NOT
ENTIRELY OUT OF THE PICTURE ON SATURDAY, STILL ANTICIPATING SOME
SCATTERED CONVECTION FOCUSED OVER NORTHEASTERN PORTIONS OF THE
FORECAST AREA, WITH SUNDAY EXPECTED TO BE DRY WITH WEAK RIDGING
MOVING IN.
GUIDANCE INDICATES THE BREAK IN THE ACTION WILL BE SHORT LIVED,
HOWEVER, WITH YET ANOTHER LOW APPROACHING THE PACIFIC COAST SUNDAY
AFTERNOON. MOST GUIDANCE SHOWS THIS SYSTEM TRACKING EASTWARD INTO
THE DESERT SOUTHWEST TO START THE WORK WEEK, BUT THE ENSEMBLES
DIVERGE NOTICEABLY WITH THE REGARD TO THE POTENTIAL TRACK OF THE
SYSTEM AND HOW MUCH IT WILL WEAKEN ONCE ONSHORE. STILL, CONFIDENCE
IS INCREASING WITH REGARD TO A RELATIVELY QUICK RETURN TO
UNSETTLED WEATHER, AT LEAST FOR SOUTHERN UTAH.
AVIATION
KSLC...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE
OVERNIGHT HOURS WITH SOUTHERLY WINDS. PERIODIC SHOWERS ARE
EXPECTED TO DEVELOP TOMORROW MORNING, MOST LIKELY BETWEEN 10Z AND
12Z, BRINGING THE POTENTIAL FOR PERIODS OF GUSTY AND ERRATIC WINDS
THROUGH THE MORNING. BY THE LATE AFTERNOON, ADDITIONAL SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP, WITH A 30
PERCENT CHANCE OF PRODUCING GUSTY WINDS THROUGH THE EARLY EVENING
TOMORROW.
REST OF UTAH AND SOUTHWEST WYOMING...VFR CONDITIONS ARE EXPECTED
ACROSS THE AIRSPACE THROUGH THE OVERNIGHT HOURS. THE CURRENT ROUND
OF SHOWERS AND THUNDERSTORMS OVER NORTHEASTERN PORTIONS OF THE
AREA IS DIMINISHING, BUT ANOTHER ROUND IS EXPECTED DURING THE
EARLY MORNING, MOST LIKELY BEGINNING BETWEEN 10Z AND 12Z, FOCUSED
OVER NORTHERN PORTIONS OF THE AIRSPACE, LASTING THROUGH MUCH OF
THE MORNING. ADDITIONAL SHOWERS AND THUNDERSTORMS ARE THEN
EXPECTED TO DEVELOP BY LATE AFTERNOON, AGAIN PRIMARILY FOR
NORTHERN PORTIONS OF THE AIRSPACE. ANY STORMS THAT DEVELOP WILL
HAVE THE POTENTIAL TO PRODUCE GUSTY AND ERRATIC WINDS, LIGHTNING,
AND BRIEF MOUNTAIN OBSCURATIONS.
FIRE WEATHER
SHOWERS AND THUNDERSTORMS OVER NORTHEAST UTAH ARE
WEAKENING THIS EVENING, WITH ANOTHER ROUND OF SHOWERS EXPECTED FOR
NORTHERN UTAH BEGINNING EARLY THIS MORNING, LASTING INTO THE LATE
MORNING. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS WILL DEVELOP
FRIDAY AFTERNOON, WITH THE BEST COVERAGE OVER NORTHERN UTAH. ANY
STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE GUSTY AND
ERRATIC WINDS AND LIGHTNING, WITH AN ENHANCED CHANCE OF WETTING
RAINFALL. AN ASSOCIATED COLD FRONT WILL BRING DRIER CONDITIONS AND
MORE SEASONABLE CONDITIONS FOR SATURDAY, THOUGH THE THREAT OF
SHOWERS AND THUNDERSTORMS WILL LINGER OVER NORTHEAST UTAH THROUGH
SATURDAY AFTERNOON. HIGH PRESSURE WILL BRING DRY CONDITIONS FOR
SUNDAY BEFORE MOISTURE AND INSTABILITY INCREASE AGAIN TO START THE
WORK WEEK AS ANOTHER PACIFIC STORM SYSTEM MOVES ONSHORE. WITH THIS
SYSTEM MOST LIKELY EXPECTED TO MOVE INTO THE DESERT SOUTHWEST,
COVERAGE SHOULD BE BETTER FOR SOUTHERN UTAH COMPARED TO NORTHERN
UTAH FOR THE SYSTEM NEXT WEEK.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
PUBLIC...TRAPHAGAN
AVIATION...TRAPHAGAN
FIRE WEATHER...TRAPHAGAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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