Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 192224
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
424 PM MDT SAT APR 19 2014

.SYNOPSIS...A WEAK STORM SYSTEM WILL MOVE SLOWLY ACROSS THE
REGION THROUGH THE WEEKEND. A SIGNIFICANT WARMING TREND IS THEN
EXPECTED FOR THE EARLY PORTION OF THE WEEK AHEAD OF A STRONGER
STORM WHICH WILL IMPACT THE AREA BY MIDWEEK.

&&

.SHORT TERM (THROUGH 12Z TUESDAY)... UPPER LOW DRIFTING SLOW
ACROSS ARIZONA THIS AFTERNOON. TO THE NORTH OF THIS FEATURE A MID-
LEVEL DEFORMATION AXIS STRETCHES FROM SOUTHWEST UTAH THROUGH SOUTH
CENTRAL WYOMING. BENEATH THIS FEATURE NUMEROUS SHOWERS...AND
ISOLATED THUNDERSTORMS...HAVE DEVELOPED OVER UTAH/S CENTRAL AND
SOUTHERN MOUNTAINS. IN ADDITION...SHOWERS AND ISOLATED
THUNDERSTORMS HAVE DEVELOPED OVER EASTERN NEVADA AND WILL CONTINUE
TO MOVE INTO WEST CENTRAL AND SOUTHWEST UTAH THIS EVENING. TO THIS
POINT COVERAGE OVER MOST VALLEY LOCATIONS REMAINS ISOLATED.
ANTICIPATE THAT THIS ACTIVITY WILL CONTINUE THROUGH THE EVENING
BEFORE DIMINISHING AFTER SUNSET.

SUNDAY...AS UPPER LOW EXITS THE DESERT SOUTHWEST A LIFTING WAVE IN
THE NORTHERN INTERMOUNTAIN REGION NUDGES A COLD FRONT INTO UTAH
DURING THE DAY. THIS BRING A LITTLE COOLER MID LEVEL AIR INTO THE
STATE AND EXPECT HIGH TEMPERATURES TO BE A COUPLE DEGREES COOLER
THAN TODAY/S ACROSS MUCH OF CENTRAL AND NORTHERN UTAH. FRONT IS A
DECAYING FEATURE WITH LITTLE DYNAMIC SUPPORT. STILL DECENT MOISTURE
IN PLACE...AND MODELS AGAIN SHOW WEAK INSTABILITY...SO WILL KEEP
MENTION OF SCATTERED MOUNTAIN SHOWERS IN THE UINTAS AND CENTRAL
AND SOUTHERN MOUNTAINS WITH ISOLATED POPS FOR SOUTHERN AND EASTERN
VALLEYS.

SUNDAY NIGHT THROUGH MONDAY NIGHT...MID LEVEL FLOW BEGINS TO BACK
SHARPLY ON SUNDAY NIGHT AS VIGOROUS TROUGH APPROACHES THE WEST
COAST. STRONG WARM ADVECTION CONTINUES THROUGH THE DAY ON MONDAY
WITH 700 MB TEMPERATURES APPROACHING +8C BY 00Z TUESDAY. SO A
VERY WARM DAY IN STORE ON MONDAY AND SLC MAY HIT 80 FOR THE FIRST
TIME THIS YEAR. MONDAY NIGHT WILL ALSO BE QUITE MILD AS SOUTHERLY
FLOW DEVELOPS AND STRONG SOUTHERLY SURFACE GRADIENT KEEPS WINDS
GOING THROUGH THE NIGHT.

.LONG TERM (AFTER 12Z TUESDAY)...SOUTHWEST FLOW OVER THE FORECAST
AREA IS EXPECTED TO INCREASE SUBSTANTIALLY DURING THE DAY TUESDAY
AND CONTINUE INTO THE EVENING. THIS IS A RESULT OF THE NEXT PACIFIC
STORM SYSTEM APPROACHING FROM THE WEST. GFS AND ECMWF BOTH INDICATE
A 700 MB FLOW IN EXCESS OF 50 KTS JUST AHEAD OF THE FRONTAL BOUNDARY
WHICH IS EXPECTED TO PUSH INTO NORTHWEST UTAH TUESDAY AFTERNOON AND
THROUGH THE WASATCH FRONT TUESDAY EVENING. THESE CONDITIONS WILL BE
QUITE FAVORABLE FOR A HIGH WIND EVENT OVER MUCH OF THE STATE
TUESDAY. BEHIND THE FRONT...WINDS WILL DROP OFF TO BELOW ADVISORY
CRITERIA. A DRAMATIC COOLDOWN IS ALSO EXPECTED BEHIND THE COLD
FRONT. MODELS SUGGEST A -15 TO -20 DEGREE DROP IN 700 MB
TEMPERATURES FROM TUESDAY TO WEDNESDAY. REASONABLE DYNAMICS OVER
NORTHERN AND CENTRAL UTAH ALONG AND BEHIND THE FRONT COMBINED WITH
RELATIVELY GOOD MOISTURE WILL ALLOW GOOD...BUT NOT GREAT
PRECIPITATION AMOUNTS. SNOW IS LIKELY IN THE MOUNTAINS AND COULD
REACH DOWN TO THE VALLEY FLOORS WEDNESDAY MORNING...ALTHOUGH
AMOUNTS WILL BE LOW AND SHORT LIVED.

BY WEDNESDAY NIGHT...THE TROUGH IS EXPECTED TO EXIT THE AREA IF YOU
BELIEVE THE ECMWF WHILE THE GFS SOLUTION IS CONSIDERABLY SLOWER.
EITHER WAY A RIDGE WILL FOLLOW FOR FRIDAY AND SHIFT EAST SATURDAY.
MODELS THEN SUGGEST NEXT SYSTEM FOR LATTER HALF OF THE WEEKEND...BUT
STILL TOO EARLY TO DISCUSS TIMING AND STRENGTH OF SYSTEM.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT THE SLC TERMINAL
THROUGHOUT THE DAY WITH MOSTLY CLOUDY SKIES. LIGHT NORTHWEST WINDS
ARE EXPECTED TO SHIFT TO THE SOUTHEAST BETWEEN 03Z AND 04Z. THERE IS
A 20 PERCENT CHANCE THAT SHOWERS IN THE VICINITY OF THE TERMINAL
WILL RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS THIS AFTERNOON.

&&

&&

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

$$

PUBLIC...GRAHAM
AVIATION...YOUNG

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)



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