878
FXUS65 KSLC 150918
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
318 AM MDT SUN JUN 15 2025
SYNOPSIS
HOT, DRY, AND INCREASINGLY BREEZY CONDITIONS WILL
CONTINUE THROUGH MONDAY ACROSS UTAH AND SOUTHWEST WYOMING. A DRY
COLD FRONT WILL CROSS THE AREA LATE MONDAY INTO TUESDAY, BRINGING
A TEMPORARY DECREASE IN WINDS AND TEMPERATURES. HOWEVER, HIGH
PRESSURE WILL RETURN BY THURSDAY, WITH CONDITIONS BECOMING
INCREASINGLY BREEZY BY THE WEEKEND.
SHORT TERM (THROUGH 12Z/6AM TUESDAY)
HIGH PRESSURE IS CENTERED
OVER SOUTHERN NEW MEXICO THIS MORNING WITH A TROUGH POSITIONED
NEAR THE PACIFIC COAST. IN BETWEEN THESE TWO FEATURES, UTAH AND
SOUTHWEST WYOMING REMAINS UNDER A VERY DRY SOUTHWEST FLOW, WITH AN
INCREASINGLY HOT AIRMASS ADVECTING IN. TEMPERATURES ARE ON TRACK
TO INCREASE BY A FEW DEGREES COMPARED TO YESTERDAY'S HIGHS. THIS
WILL RESULT IN MAXES AVERAGING 15-20F ABOVE SEASONAL NORMALS OVER
NORTHERN PORTIONS OF THE AREA, AND 5-10F ABOVE CLIMO OVER SOUTHERN
PORTIONS OF THE AREA. DUE TO THE TROUGH, WINDS WILL BE A BIT
BREEZY, PRIMARILY OVER WESTERN UTAH, THIS AFTERNOON. COMBINED WITH
THE VERY DRY AIRMASS, THERE COULD BE SOME ISOLATED CRITICAL FIRE
WEATHER CONDITIONS.
BY MONDAY AFTERNOON, THE PACIFIC TROUGH WILL BE POSITIONED OVER
CALIFORNIA, RESULTING IN A NOTICEABLE INCREASE IN THE FLOW ALOFT
ACROSS UTAH AND SOUTHWEST WYOMING, AND THUS THE SURFACE WINDS. AS
A RESULT, CRITICAL FIRE WEATHER CONDITIONS WILL BECOME MORE
WIDESPREAD. THE GOING FIRE WEATHER WATCH HAS BEEN UPGRADED TO A
RED FLAG WARNING WITH THIS PACKAGE. THE TROUGH IS EXPECTED TO
CROSS THE AREA MONDAY NIGHT INTO TUESDAY, BRINGING DECREASING
WINDS AND TEMPERATURES WITH A SLIGHT INCREASE IN RELATIVE
HUMIDITY. LITTLE TO NO PRECIPITATION IS ANTICIPATED IN ASSOCIATION
WITH THE SYSTEM.
LONG TERM (AFTER 12Z/6AM TUESDAY)
A DRY COLD FRONT AND ASSOCIATED
LONGWAVE TROUGH WILL HAVE TRACKED ACROSS MUCH OF UTAH BY TUESDAY
MORNING. THE FRONT WILL TRACK SOUTH AND EAST ACROSS SOUTHERN UTAH
INTO THE AFTERNOON. ALTHOUGH THERE IS NO MEASURABLE PRECIPITATION
FORECAST, THERE WILL BE A SLIGHT COOL DOWN. VALLEY TEMPERATURES WILL
COOL AROUND 5-10F FROM MONDAY, WITH THE MOST COOLING FOR SOUTHWEST
WYOMING AND NORTHERN UTAH. THE SEVERAL CONSECUTIVE DAYS OF LOW
RELATIVE HUMIDITY, GUSTY SOUTHWEST WINDS, AND HIGH FIRE DANGER WILL
BE SOMEWHAT MITIGATED. VERY DRY CONDITIONS WILL CONTINUE WITH
NORTHWEST WINDS BEHIND THE FRONT. WINDS WILL BE OCCASIONALLY GUSTY,
BUT LIGHTER THROUGHOUT COMPARED TO MONDAY.
A RIDGE TO THE SOUTHEAST WILL RETROGRADE TO OFF THE COAST OF
SOUTHERN CALIFORNIA AND BAJA CALIFORNIA AS THE TROUGH TRACKS
THROUGH. THE RIDGE WILL TRACK SLIGHTLY EASTWARD WEDNESDAY WITH
SLIGHTLY WARMER TEMPERATURES. FLOW WILL BE ZONAL TO SOUTHWEST WITH
RELATIVELY LIGHT WIND SPEEDS.
THE PATTERN WILL BECOME SIMILAR TO EARLY IN THE WEEK FOR THURSDAY,
WITH THE RIDGE IN A SIMILAR POSITION OVER ARIZONA AND NEW MEXICO. AS
ANOTHER LONGWAVE TROUGH DIGS INTO THE PACNW, SOUTHWEST FLOW WILL
ENHANCE. THIS WILL BE WITH CONTINUED RELATIVE HUMIDITY VALUES EACH
DAY INTO THE SINGLE DIGITS AND TEENS. ALONG WITH INCREASED FIRE
DANGER WILL BE TEMPERATURES IN RECORD TERRITORY FOR THAT DAY. THE
NATIONAL BLEND OF MODELS BRINGS TRIPLE DIGITS TO MOST VALLEYS,
INCLUDING THE URBAN CORRIDOR OF NORTHERN UTAH. THE FORECAST HIGH OF
101F AT SALT LAKE CITY INTERNATIONAL AIRPORT WOULD TIE THE RECORD
FOR THAT DAY. THE WARMEST CONDITIONS WILL BE IN LOWER WASHINGTON
COUNTY, AROUND LAKE POWELL, AND INTO EASTERN UTAH.
THERE IS GOOD MODEL AGREEMENT THAT THE LONGWAVE TROUGH WILL TRACK
INLAND LATER FRIDAY OR SATURDAY. AS IT APPROACHES, A PRESSURE
GRADIENT WILL STRENGTHEN, ALLOWING FOR STRONGER SOUTHWEST WINDS.
THERE WILL BE SLIGHT COOLING FRIDAY AS THAT SYSTEM APPROACHES, BUT
WINDS WILL LIKELY INCREASE FROM THURSDAY, CONTINUING HIGH FIRE
DANGER.
THERE IS RELATIVELY GOOD AGREEMENT ON THE TRACK OF THAT SYSTEM INTO
SATURDAY, BUT PRECISE TIMING OF THE FRONT IS LOWER CONFIDENCE.
SATURDAY WILL BE COOLER THAN FRIDAY, LIKELY WITH A COLD FRONT
TRACKING INTO AT LEAST SOUTHWEST WYOMING AND NORTHERN UTAH AT SOME
POINT. SOUTH OF THAT BOUNDARY, STRONG SOUTHWEST WINDS AND LOW
RELATIVE HUMIDITY WILL COME WITH HIGH FIRE DANGER.
AVIATION...KSLC
SOUTHEAST WINDS WILL PREVAIL THROUGH AROUND 21Z.
LIGHT SPEEDS WILL LAST THROUGH AROUND 15Z, WITH GUSTS AROUND 20
KNOTS FROM 15Z TO WHEN WINDS TRANSITION TO NORTHWEST. THE TRANSITION
TO NORTHWEST FLOW WILL BE BETWEEN 19-21Z. SCATTERED CLOUDS WILL
PREVAIL WITH CLEARING INTO THE EVENING.
REST OF UTAH AND SOUTHWEST WYOMING
LIGHT WINDS RANGING FROM
SOUTHEAST TO SOUTHWEST WILL PREVAIL THROUGH AROUND 15Z. WINDS WILL
INCREASE LATE MORNING INTO THE AFTERNOON, WITH GUSTS AROUND 25 KNOTS
FOR SOUTHWEST WYOMING AND SOUTHWEST UTAH. GUSTS WILL BE AROUND 20
KNOTS FOR MOST OTHER PORTIONS OF UTAH. SCATTERED CLOUDS WILL PREVAIL
THROUGH THE DAY.
FIRE WEATHER
HOT AND DRY SOUTHWEST FLOW PERSISTS OVER UTAH
BETWEEN A RIDGE OVER THE DESERT SOUTHWEST AND A TROUGH OFF THE
PACIFIC COAST. WINDS WILL PICK UP ON MONDAY AS THE TROUGH MOVES
EASTWARD, RESULTING IN CRITICAL FIRE WEATHER CONDITIONS WHERE
FUELS ARE SUFFICIENTLY DRY OVER SOUTHERN UTAH. THE TROUGH WILL
CROSS THE AREA MONDAY NIGHT INTO TUESDAY, BRINGING A SLIGHT
INCREASE IN RELATIVE HUMIDITY AND A DECREASE IN TEMPERATURES.
BEHIND THE TROUGH, HIGH PRESSURE WILL QUICKLY BUILD AGAIN BY
THURSDAY, BRINGING A RETURN TO THE HOT AND VERY DRY WEATHER WITH
INCREASINGLY BREEZY CONDITIONS.
SLC WATCHES/WARNINGS/ADVISORIES
UT...RED FLAG WARNING FROM NOON MONDAY TO MIDNIGHT MDT MONDAY NIGHT
FOR UTZ489-494>498.
WY...NONE.
SHORT TERM/FIRE WEATHER...TRAPHAGAN
LONG TERM/AVIATION...WILSON
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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