Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 292225
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
425 PM MDT WED APR 29 2015

.SYNOPSIS...A WEAK COLD FRONT WILL CROSS NORTHERN UTAH TONIGHT AND
SETTLE INTO CENTRAL UTAH TOMORROW. AN INCREASE IN INSTABILITY WILL
SUPPORT DAILY ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE WEEKEND.

&&

.SHORT TERM (THROUGH 12Z SUNDAY)...THE AXIS OF THE UPPER RIDGE HAS
SHIFTED EAST OF UTAH THIS AFTERNOON AHEAD OF A TROUGH OVER THE
PACIFIC NORTHWEST. A WEAK DISTURBANCE PRECEDES THE MAIN TROUGH AND
IS CURRENTLY RESPONSIBLE FOR SOME CUMULUS DEVELOPMENT ACROSS FAR
NORTHWEST UTAH AND ISOLATED THUNDERSTORMS OVER NORTHEAST NEVADA.
SOME OF THESE THUNDERSTORMS COULD DEVELOP INTO NORTHWEST UTAH THIS
EVENING AS A COLD FRONT CURRENTLY OVER NORTH-CENTRAL NEVADA AND
SOUTH-CENTRAL IDAHO PUSHES INTO UTAH. OTHERWISE...SOME MOSTLY FLAT
CUMULUS ARE ALSO SEEN ALONG THE HIGH TERRAIN OF MAINLY NORTHERN
UTAH.

THE AFOREMENTIONED COLD FRONT WILL MAKE IT INTO CENTRAL UTAH
OVERNIGHT BEFORE STALLING...AS THE UPPER TROUGH WILL END UP JUST
GRAZING NORTHERN UTAH. THE SHALLOW NATURE OF THE COLD FRONT WILL NOT
BRING ABOUT A SIGNIFICANT DROP IN TEMPERATURES ACROSS NORTHERN UTAH
TOMORROW. INCREASING MOISTURE OVER THE AREA THROUGH TOMORROW WILL
ALLOW FOR A BETTER CHANCE OF SHOWERS TOMORROW...WITH PARTICULAR
FOCUS ACROSS CENTRAL UTAH NEAR THE STALLED BOUNDARY AND OVER THE
HIGHER TERRAIN. THIS PATTERN WILL CONTINUE INTO FRIDAY...ALTHOUGH
TEMPERATURES WILL TREND SLIGHTLY WARMER.

THE MOISTURE WILL REMAIN IN PLACE ON SATURDAY...BUT MODELS ALSO LIFT
A WEAK DISTURBANCE FROM THE BAJA COAST INTO THE AREA. AT THIS
TIME...THE NORTHERN PORTIONS OF THE FORECAST AREA LOOKS TO BE THE
MAIN AREA OF FOCUS FOR CONVECTION...ALONG WITH THE HIGH TERRAIN.

.LONG TERM (AFTER 12Z SUNDAY)...MID LEVEL CONVERGENT FLOW ACROSS THE
EASTERN GREAT BASIN WILL MAINTAIN MODEST MOISTURE CONVERGENCE OVER
THE AREA TO BEGIN THE LONG TERM...PWAT RANGING FROM .45 TO
.70 INCHES NOTED IN GFS BOTH SUN/MON. BUFR SOUNDINGS INDICATE BULK
OF THE COLUMN MOISTURE WILL REMAINING ABOVE H6 WITH LOW LEVELS
REMAINING QUITE DRY. DIURNALLY DRIVEN CONVECTION WILL REMAIN THE
NORM BOTH DAYS...WITH SPOTTY PRECIP AND GUSTY WINDS THE LIKELY
OUTCOME FROM CELLULAR DEVELOPMENT.

GLOBALS CONTINUE TO SUGGEST A WEAK TROUGH OFF THE SOCAL COAST WILL
SLIDE EAST THROUGH THE DESERT SOUTHWEST THEN LIFT NORTHEAST THROUGH
COLORADO MONDAY THROUGH TUESDAY. PWAT TRENDS IN GUIDANCE CONTINUE TO
NUDGE HIGHER THROUGH THAT PERIOD AND WILL BE COUPLED WITH WEAK UPPER
DIFFLUENCE TO POTENTIALLY GENERATE MORE SCATTERED /LIKELY LESS
TERRAIN DEPENDENT/ CONVECTION...ESPECIALLY ACROSS THE SOUTH AND
EAST.

MODEL TO MODEL AND RUN TO RUN CONSISTENCY BEGINS TO WANE MORE
SIGNIFICANTLY LATER TUESDAY THROUGH MIDWEEK...THIS REGARDING TRACK
AND EVOLUTION OF THE NEXT PACNW TROUGH. NOT BUYING OFF ON ANY ONE
SOLUTION AT THIS TIME.

&&

.AVIATION...LIGHT NORTHWESTERLY SURFACE WINDS ARE EXPECTED TO REMAIN
IN PLACE THROUGH 02/03Z BEFORE RETURNING BACK TO THE SOUTHEAST. A
FRONTAL BOUNDARY IS EXPECTED TO MOVE THROUGH THE TERMINAL BETWEEN 07-
09Z SWITCHING WINDS BACK TO THE NORTHWEST. THIS SAID...A 30 PERCENT
CHANCE EXISTS THAT WINDS BEHIND THE FRONT WILL REMAIN LIGHT AND
VARIABLE INTO TOMORROW MORNING.

&&

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

$$

CHENG/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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