Area Forecast Discussion
Issued by NWS Salt Lake City, UT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
000
FXUS65 KSLC 172209
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
409 PM MDT THU APR 17 2014

.SYNOPSIS...HIGH PRESSURE WILL SPREAD ACROSS THE REGION THROUGH
TONIGHT. THE NEXT WEAKENING STORM SYSTEM WILL CROSS THE REGION
LATE FRIDAY THROUGH SATURDAY. A STRONGER STORM WILL IMPACT THE
AREA MIDWEEK OF NEXT WEEK.

&&

.SHORT TERM (THROUGH 00Z MONDAY)...SHORT WAVE RIDGE IN PLACE WILL
FLATTEN AND SHIFT EAST TOMORROW AS A SPLITTING TROUGH MOVES INTO
THE WESTERN CONUS. THESE FEATURES SHOW UP WELL IN AFTERNOON
SATELLITE IMAGERY WITH THE NORTHERN SPLIT ENCROACHING ON THE
OREGON COAST AND THE SOUTHERN FALLING INTO A CLOSED CIRCULATION
OFF THE SOCAL COAST.

THE MORE PROGRESSIVE NORTHERN BRANCH OF THIS SPLIT WILL TRACK
THROUGH THE NORTHERN ROCKIES LATE TONIGHT THROUGH TOMORROW FORCING
A WEAK COLD FRONT TO MOVE INTO NORTHWESTERN UTAH BY DAWN. STRONG
WARM ADVECTION AHEAD OF THIS WILL CONTINUE INTO THE OVERNIGHT AND
ALLOW FOR WARMER LOW TEMPS TOMORROW MORNING. BREEZY SOUTHERLY
WINDS ACROSS THE WESTERN VALLEYS WILL REMAIN IN PLACE AS A THIS
FRONT ENCROACHES AS WELL WITH SHARPENING MSLP GRADIENT. MODELS
AGREE THIS FRONT WILL REACH AS FAR SOUTH AS ABOUT NEPHI TOMORROW
AFTERNOON BEFORE STALLING AS UPPER SUPPORT SHIFT EAST. MODEST LOW
LEVEL INSTABILITY IN WAKE OF ITS PASSAGE WILL PROVIDE CONVECTIVE
SUPPORT AND A FOCUS FOR SHALLOW DEVELOPMENT...ESPECIALLY TOMORROW
AFTERNOON INTO THE OVERNIGHT HOURS FOR AREAS ROUGHLY PROVO NORTH.
FINE TUNED FRONTAL ZONE IN GRIDS THIS SHIFT BUT NO MAJOR CHANGES.

MEANWHILE THE SOUTHERN BRANCH CIRCULATION WILL REMAIN CLOSED INTO
TOMORROW THEN OPEN AND LIFT NORTHEAST ADVECTING MOISTURE INTO THE
SOUTH SOUTHERN THIRD OF THE STATE TOMORROW AFTERNOON. SUBTLE CAPE
OVER THE HIGH TERRAIN WILL LIKELY YIELD ISOLATED STORMS OVER THE
MOUNTAINS TOMORROW AFTERNOON.

MODELS CONTINUE TO INDICATE A WEAK DEFORMATION FORMING OVER
CENTRAL UTAH FRIDAY NIGHT THROUGH SATURDAY AS THE SOUTHERN BRANCH
LIFTS INTO AND THROUGH THE 4-CORNERS. THIS AREA OF WEAK DYNAMIC
LIFT WILL GRADUALLY SHIFT OVER THE EAST...BUT CONVECTION STILL
APPEARS SCATTERED AT BEST AND GENERALLY QUITE SHALLOW. AS THE
TROUGH SHIFTS EAST SUNDAY DIURNAL INSTABILITY COMBINED WITH
REMNANT LOW LEVEL MOISTURE WILL KEEP A CHANCE OF CONVECTION OVER
GENERALLY FROM I-15 EAST AND INCREASED POPS A FAIR BIT FOR THE
AFTERNOON HOURS.

&&

.LONG TERM (AFTER 00Z MONDAY)...TEMPERATURES WILL RISE MONDAY AHEAD
OF A LARGE UPPER LOW THAT WILL BRING COOLER...WETTER WEATHER TO THE
FORECAST AREA MIDWEEK. STRONG SOUTHWESTERLY WINDS WILL DEVELOP
TUESDAY AHEAD OF THE COLD FRONT ASSOCIATED WITH THE LOW. THE GFS AND
EC SHOW 700MB WINDS IN THE 40 TO 50 KNOT RANGE ON TUESDAY
AFTERNOON...WITH SLIGHTLY STRONGER WINDS IN THE GFS. THE STRONG
UPPER LEVEL WINDS ALONG WITH A FAVORABLE SURFACE GRADIENT WILL
RESULT IN A VERY WINDY DAY TUESDAY ACROSS THE MAJORITY OF THE
FORECAST AREA. THE COLD FRONT WILL MOVE THROUGH THE CWA LATE TUESDAY
INTO WEDNESDAY. BOTH MODELS SHOW 700MB TEMPERATURES DROPPING TO -10C
ACROSS NORTHERN UTAH WEDNESDAY AFTERNOON IN PRECIP...WHICH WOULD BE
COLD ENOUGH FOR SNOW TO MIX DOWN TO THE VALLEY FLOORS.

THE EC IS MORE PROGRESSIVE WITH THE SYSTEM THAN THE GFS...MOVING THE
PRECIP OUT OF THE FORECAST AREA THURSDAY. THE GFS CLOSES THE UPPER
LOW OFF OVER NORTHERN UTAH...KEEPING THE PRECIP GOING ACROSS THE
HIGHER TERRAIN THURSDAY.

&&

.AVIATION...WINDS AT THE SLC TERMINAL WILL SHIFT TO THE NORTHWEST
AND BECOME LIGHT BETWEEN 23Z AND 00Z. HOWEVER...THERE IS A 20
PERCENT CHANCE THAT WINDS WILL REMAIN FROM THE SOUTH THROUGH THE
EVENING. VFR CONDITIONS WILL PREVAIL.


&&

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

$$

MERRILL/HOSENFELD


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)



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.