Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 280901
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
301 AM MDT TUE APR 28 2015

.SYNOPSIS...HIGH PRESSURE WILL REMAIN IN PLACE THROUGH WEDNESDAY.
A WEAK COLD FRONT WILL SAG INTO NORTHERN UTAH ON THURSDAY.

&&

.SHORT TERM (THROUGH 12Z FRIDAY)...
WATER VAPOR LOOP SHOWS A RIDGE BUILDING INTO THE INTERIOR WEST. THE
NEXT SYSTEM IS WELL OFF THE BRITISH COLUMBIA/PACIFIC NORTHWEST
COAST. AMDAR 400-250MB WIND OBSERVATIONS SHOW A 75-130KT
ANTICYCLONIC JET OVER WESTERN CANADA AND THE ROCKIES.
GOES/GPS/RAP/00Z SLC RAOB INDICATE THE PRECIPITABLE WATER VALUE
RANGES BETWEEN 0.10"-0.20" FAR WESTERN VALLEYS AND MOUNTAINS...TO
0.40"-0.50" ACROSS THE CENTRAL AND EASTERN VALLEYS. BLENDED TOTAL
PRECIPITABLE WATER PRODUCT INDICATES VALUES ABOVE NORMAL ACROSS THE
ROCKIES AND WESTERN CANADA...BELOW NORMAL ACROSS THE REST OF THE
WEST.

A RIDGE OF HIGH PRESSURE BUILDS IN PROMOTING A WARMING TREND EARLY
IN THE WORK WEEK AHEAD OF AN APPROACHING COLD FRONT. SHORT RANGE
ENSEMBLES INDICATE STABLE CONDITIONS TODAY...FOLLOWED BY INCREASING
INSTABILITY ACROSS THE NORTH WEDNESDAY. ADDED ISOLATED SHOWERS TO
THE RAFT RIVER AND UINTA MOUNTAINS.

THE COLD FRONTAL PASSAGE IS EXPECTED LATE WEDNESDAY NIGHT INTO
THURSDAY. KEPT ISOLATED TO SCATTERED CONVECTION IN THE
FORECAST...AND THE IDEA OF DRYING ALONG THE IDAHO BORDER THURSDAY.

.LONG TERM (AFTER 12Z FRIDAY)...
FRONTAL BOUNDARY REMAINS STALLED OVER CENTRAL UTAH FRIDAY THROUGH
EARLY NEXT WEEK AS IT GRADUALLY WEAKENS. FOCUS OF CONVECTION WILL
PRIMARILY BE OVER THE HIGHER TERRAIN IN THE VICINITY OF THIS
BOUNDARY. HOWEVER...THE AIRMASS IS OTHERWISE RELATIVELY DRY SO
CONVECTION WILL INITIALLY BE MORE ISOLATED IN NATURE. SHORTWAVE
ENERGY FROM A WEAKENING CALIFORNIA TROUGH IS EXPECTED TO PROVIDE
ADDITIONAL MOISTURE AND INSTABILITY SATURDAY AND
SUNDAY...INCREASING COVERAGE OF CONVECTION JUST A BIT. THIS EFFECT
IS MORE PRONOUNCED IN THE GFS COMPARED TO THE EC.

ON MONDAY...MODELS INDICATE A SLIGHTLY STRONGER TROUGH MOVING
ONSHORE ALONG THE SOUTHERN CALIFORNIA COAST. THIS IS PROGGED TO MOVE
ACROSS ARIZONA AND NEW MEXICO THROUGH WEDNESDAY...DRAWING ADDITIONAL
MOISTURE AND INSTABILITY INTO THE FORECAST AREA. MODELS HAVE BEEN
FAIRLY CONSISTENT WITH THE TIMING AND TRACK OF THIS SYSTEM...SO HAVE
RAISED POPS A BIT FOR THE EXTENDED PERIOD...PRIMARILY OVER SOUTHERN
UTAH. LITTLE CHANGE IN TEMPERATURES IS EXPECTED IN THE LONG TERM
PERIOD...WITH MAXES GENERALLY REMAIN AROUND 10F ABOVE SEASONAL
NORMS.

&&

.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS AND CLEAR SKIES
THROUGHOUT THE DAY. SOUTHEAST WINDS ARE EXPECTED TO SHIFT TO THE
NORTHWEST BETWEEN 18Z AND 20Z.

&&

.FIRE WEATHER...A WARMING AND DRYING TREND IS FORECAST TO CONTINUE
INTO MID WEEK. A FEW SHOWERS ARE POSSIBLE ACROSS THE UINTA AND RAFT
RIVER MOUNTAINS WEDNESDAY. SNOW LEVEL WILL BE BETWEEN 9KFT AND
10KFT.

SOUTHERLY WINDS WILL INCREASE A BIT WEDNESDAY AFTERNOON AHEAD OF THE
NEXT COLD FRONT. THIS FRONT IS FORECAST TO CROSS NORTHERN UTAH
THURSDAY...STALLING ACROSS CENTRAL UTAH FRIDAY. WINDS WILL SHIFT TO
THE NORTH WITH SLIGHT COOLING AND MOISTENING. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WILL BE A THREAT ACROSS THE NORTHERN AND
CENTRAL ZONES.

&&

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

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...TRAPHAGAN

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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