Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 102112
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
312 PM MDT THU APR 10 2014

.SYNOPSIS...A MILD WESTERLY FLOW ALOFT WILL PREVAIL THROUGH THE
REMAINDER OF THE WEEK. A PAIR OF WEAK SYSTEMS WILL AFFECT THE
REGION DURING THE UPCOMING WEEKEND.

&&

.SHORT TERM (THROUGH 12Z SUNDAY)...
WATER VAPOR LOOP SHOWS A LAST DISTURBANCE OVER THE NORTHERN
ROCKIES...AHEAD OF AN EXPANSIVE RIDGE BUILDING INTO THE WESTERN
CONUS. AMDAR 400-250MB WIND OBSERVATIONS REVEAL A CYCLONIC
75-125KT JET FROM BRITISH COLUMBIA ACROSS THE NORTHERN ROCKIES.
MEANWHILE A WESTERLY 75-125KT JET EXTENDED FROM SOUTHERN
CALIFORNIA TOWARD THE FOUR CORNERS. GOES/GPS/RAP/12Z RAOB INDICATE
THE PRECIPITABLE WATER VALUE RANGES BETWEEN 0.16" AND 0.48".

TRANQUIL CONDITIONS THROUGH FRIDAY MORNING AS THE RIDGE BUILDS IN.

EXPECT INCREASING CLOUDS FROM FRIDAY AFTERNOON WITH THE RIDGE AXIS
SLIDING OVERHEAD. PLENTY OF MID AND HIGH LEVEL MOISTURE AS THE
APPROACHING CALIFORNIA LOW OPENS UP.

STILL HAVE CONVECTION IN THE FORECAST SATURDAY
AFTERNOON...ESPECIALLY ACROSS THE SOUTH AND IN THE HIGHER
TERRAIN. 15Z SHORT RANGE ENSEMBLES INDICATE PLENTY OF INSTABILITY IN
PLACE WITH THE FIRST DISTURBANCE PASSING OVERHEAD. ADDED MENTION OF
THUNDER PER 15Z SHORT RANGE ENSEMBLE THUNDER GUIDANCE.

NORTHERN STREAM TROUGH SWINGS TOWARD NORTHERN UTAH SATURDAY NIGHT.
12Z EUROPEAN IS STILL STRONGER AND COLDER THAN THE GFS. INCREASED
POPS TO MID AND HIGH CHANCE RANGE ACROSS THE NORTH OWING TO THE
EUROPEAN SOLUTION. GETS COLD ENOUGH FOR HIGH ELEVATION
SNOWFALL...WITH POTENTIAL FOR BENCH SNOW SHOULD THE COLDER AND
WETTER EUROPEAN VERIFY. EUROPEAN SOLUTION ALSO HAS A STRONGER COLD
FRONT WITH A FURTHER SOUTH PROGRESSION OF SHOWERY AND GUSTY ACTIVITY.

&&

.LONG RANGE (AFTER 12Z SUNDAY)...
12Z RUNS OF THE GFS/ECMWF HAVE SHIFTED THE UPPER COLD POOL OF THE
SUNDAY TROUGH WEST RESPECTIVE TO THEIR PREVIOUS RUNS. DIFFERENCES
IN DETAILS REMAIN...BUT CONFIDENCE IN A COLDER OUTCOME HAS
INCREASED. THE FURTHER WEST SOLUTION OF THE ECMWF ALLOWS FOR A
STRONGER FRONT AND LONGER DURATION OF INSTABILITY OVER A MORE
BROAD AREA. THE COLD POOL IN THE GFS PROGRESSES THROUGH THE AREA
ABOUT 6 HOURS FASTER LIMITING BREADTH OF PRECIP AND RETAINS ITS
FOCUS OVER THE NORTH. H7 TEMPS CONTINUE TO RUN WARMER THAN THE EC
BUT HAVE FALLEN TO -5C ACROSS THE NORTH. DUE TO INCREASED
CONFIDENCE OF HAVING SOME SORT OF COLD POOL PASSAGE BEHIND THE
FRONT SUNDAY BOOSTED POPS TO CHANCE VALLEYS AND LIKELY PRONE
MOUNTAINS /NORTH/ AND ADDED SOME SLIGHT CHANCE/CHANCE POPS ACROSS
THE SOUTH. TEMPS MANY AREAS WILL BE KNOCKED BACK DOWN TO NEAR OR
SLIGHTLY BELOW CLIMO SUNDAY DUE TO THE FRONTAL PASSAGE.

SHORT WAVE RIDGING AND ASSOCIATED WARMING REMAINS ON TAP EARLY NEXT
WEEK. THE AFOREMENTIONED DIFFERENCES IN THE AMPLIFICATION AND TRACK
OF SAT/SUN TROUGH BECOME AMPLIFIED FOR THE LATTER PERIODS. OPTED TO
CONTINUE A NEAR CLIMO POP TREND AS A PROGRESSIVE NEAR WESTERLY FLOW
DOES APPEAR...BUT THE LOCATION AND STRENGTH OF COINCIDENT SHORT
WAVES REMAINS A LOW CONFIDENCE FORECAST.

&&

.AVIATION...NORTHWEST SURFACE WINDS WILL REMAIN IN PLACE AT THE KSLC
TERMINAL THROUGH 03/04Z BEFORE RETURNING TO THE SOUTHEAST FOR THE
OVERNIGHT HOURS. VFR CONDITIONS WILL HOLD THROUGH THE VALID TAF
PERIOD.

&&

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

$$

SHORT TERM...ROGOWSKI
LONG TERM/AVIATION...MERRILL

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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