Back to Main Page
Back to Products Page

Current Version                Previous Version:  1  2  3  4  5  

AREA FORECAST DISCUSSION

 
 FXUS65 KSLC 302218
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
418 PM MDT MON MAR 30 2015

.SYNOPSIS...A WARM SOUTHWEST FLOW ALOFT WILL DEVELOP ACROSS
UTAH TUESDAY...FOLLOWED BY A COUPLE OF COLD PACIFIC WEATHER
DISTURBANCES FOR THE MIDDLE PORTION OF THE WEEK. HIGH PRESSURE
ALOFT WILL RETURN FOR LATE FRIDAY AND INTO THE FIRST HALF OF THE
UPCOMING WEEKEND.

&&

.SHORT TERM (THROUGH 12Z FRIDAY)...CONVECTION TIED TO THE HIGHER
SOUTHERN TERRAIN PERSISTS LATE THIS AFTERNOON. THIS CONVECTION
DOES APPEAR TO HAVE SOME DYNAMIC SUPPORT FROM THE VORTICITY
MAXIMUM CURRENTLY OFF THE SOUTHWEST CORNER OF UTAH. THIS DYNAMIC
LIFT WILL SUSTAIN CONVECTION INTO EARLY THIS EVENING. THE
WEAKENING OF THE VORTICITY MAX AND THE LOSS OF DAYTIME HEATING
SHOULD BRING SHOWERS/ISOLATED THUNDERSTORMS TO AN END BY AROUND
MID-EVENING.

THE LOW-AMPLITUDE RIDGE TO THE WEST OF UTAH AT THIS TIME WILL
SLIDE EAST ACROSS THE STATE LATE TONIGHT/TUESDAY MORNING. TRAILING
THIS RIDGE WILL BE AN INCREASINGLY STRONG AND WARM SOUTHWEST FLOW
AHEAD OF WHAT WILL BE A COUPLE OF COLD PACIFIC TROUGHS MIDWEEK.
THE FIRST TROUGH WILL MOVE EAST ACROSS THE NORTHERN ROCKIES AND
THE NORTHERN GREAT BASIN TUESDAY NIGHT/WEDNESDAY. THE ASSOCIATED
SURFACE COLD FRONT WILL ENTER NORTHWEST UTAH AROUND MIDDAY
TUESDAY...THEN STALL WAITING FOR THE ARRIVAL OF THE COLDER AIR
ALOFT LATER IN THE AFTERNOON. THE TIGHTENING SURFACE GRADIENT
DURING THE AFTERNOON ALONG WITH GOOD MIXING WILL ALLOW TEMPS TO
CLIMB TO RECORD LEVEL AND PRODUCE STRONG SOUTHERLY WINDS OVER THE
WESTERN VALLEYS. THE FRONT WILL ACCELERATE EAST DURING THE LATE
AFTERNOON AND EVENING...WITH STRONG NORTHWEST POST-FRONTAL WINDS
AND A DRAMATIC DROP IN TEMPS DURING THE EVENING. WIND GUSTS COULD
BECOME QUITE STRONG OVER THE SALT FLATS...AND MAY REQUIRE
HIGHLIGHTS IN SUBSEQUENT FORECASTS.

THE TRAILING SECOND TROUGH HAS FOR SEVERAL MODELS BEEN SHOWN TO
DEEPEN OVER THE GREAT BASIN IN RESPONSE TO UPSTREAM RIDGING OFF
THE WEST COAST. THE LATEST VERSIONS OF THE GFS/ECMWF HAVE CLOSED
THE TIMING GAP DIFFERENCE...THOUGH THE ECMWF IS STILL A BIT FASTER
PUSHING THE TROUGH EAST THROUGH UTAH ON THURSDAY. PRECIP WILL
LIKELY CONCENTRATE ALONG AND NORTH OF THE ASSOCIATED BAROCLINIC
POSITIONED FROM SOUTHWEST THROUGH EAST-CENTRAL UTAH. LOW-LEVEL
CONVERGENCE ALONG THIS BOUNDARY ALONG WITH VORTICITY LOBE ROTATING
THROUGH THE MEAN TROUGH SHOULD HAVE LITTLE TROUBLE GENERATING
LIFT AND SOLID PRECIP NEAR AND NORTH OF THE BOUNDARY. FURTHER TO
THE NORTH SCATTERED COLD AIR INSTABILITY SHOWERS ARE
LIKELY...WITH THIS ACTIVITY CONFINE TO THE HIGHER TERRAIN AND
ADJACENT VALLEY LOCATIONS. PRECIP WILL SHOW A DECREASING TREND
THURSDAY NIGHT AS THE MAIN TROUGH MOVES THROUGH THE STATE AN INTO
WESTERN COLORADO BY LATE THURSDAY NIGHT. CLEARING SKIES BEHIND THE
TROUGH WILL BRING COLD TEMPERATURES TO NORTHERN AND WESTERN
UTAH...WITH THE POTENTIAL FOR AN HARD FREEZE IN THE ACTIVE
AGRICULTURAL AREA.

&&

.LONG TERM (AFTER 12Z FRIDAY)...MEDIUM RANGE MODELS ARE IN GENERAL
AGREEMENT BUILDING SHORTWAVE RIDGING ACROSS THE FORECAST AREA
FRIDAY...FOLLOWED BY A PERIOD OF MILD AND DRY SOUTHWESTERLY FLOW
ALOFT SATURDAY INTO EARLY SUNDAY AS AN UPPER TROUGH DEVELOPS ALONG
THE WEST COAST. AS SUCH HAVE GONE WITH A DRY FORECAST FOR THIS
PERIOD ALONG WITH A WARMING TREND AREA-WIDE. THE MODELS DIVERGE IN
THE EVOLUTION OF THIS TROUGH TOWARD THE LATTER PORTION OF THE
WEEKEND INTO EARLY NEXT WEEK...WHICH LEADS TO A LOW CONFIDENCE
FORECAST FOR THE DAYS 6-7 PERIOD. THE PREVIOUS FORECAST IS FAIRLY IN
LINE WITH THE GFS SOLUTION...WHICH SLOWLY BRINGS THIS TROUGH INLAND
AND PUSHES A FRONTAL BAND INTO NORTHERN UT SUNDAY NIGHT...AND HAVE
MAINTAINED THIS IDEA FOR NOW.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT KSLC THROUGH THE
TONIGHT...WITH SOUTHEAST DRAINAGE WINDS REDEVELOPING AROUND 03Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&




SHORT TERM...CONGER
LONG TERM/AVIATION...SEAMAN

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)