Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 251008
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
408 AM MDT MON MAY 25 2015

.SYNOPSIS...A MOIST AND UNSTABLE AIRMASS WILL REMAIN IN PLACE
ACROSS THE REGION TODAY. THE NEXT STORM SYSTEM TO IMPACT THE
REGION WILL SETTLE ACROSS THE PACIFIC NORTHWEST TODAY...AND
INFLUENCE THE GREAT BASIN DURING THE MIDWEEK PERIOD. HIGH
PRESSURE WILL FOLLOW LATE IN THE WEEK INTO NEXT WEEKEND BRINGING
A WARMING AND DRYING TREND.

&&

.SHORT TERM (THROUGH 06Z THURSDAY)...A CYCLONIC NORTHWESTERLY
FLOW ALOFT PREVAILS ACROSS THE FORECAST AREA EARLY THIS
MORNING...ALONG THE WESTERN PERIPHERY OF A BROAD MID LEVEL
CIRCULATION CENTERED OVER THE CENTRAL HIGH PLAINS. MEANWHILE
LOOKING UPSTREAM...A MORE CONSOLIDATED UPPER LOW IS DROPPING SOUTH
INTO THE PACIFIC NORTHWEST...AND INDUCING WEAK MID LEVEL RIDGING
ACROSS NORTHERN NV/SOUTHWEST ID.

IN THE NEAR TERM HAVE SEEN AN INCREASE IN SHALLOW CONVECTION
ACROSS THE NORTH OVER THE PAST HOUR OR SO...LIKELY AIDED IN SOME
PART BY A WEAK PERTURBATION EVIDENT IN RAP 300MB PV ANALYSIS
PASSING THROUGH NORTHERN UT. ANOTHER MORE NOTEWORTHY FEATURE IS
DRIVING PRECIPITATION ACROSS NORTHWEST AZ WITH MORE ISOLATED
COVERAGE ACROSS SOUTHERN UT.

AMPLE BOUNDARY LAYER MOISTURE REMAINS IN PLACE ACROSS THE
FORECAST AREA...AND WITH THE ADDITION OF A LITTLE DAYTIME HEATING
SHOULD ONCE AGAIN SUPPORT SHOWERS AND ISOLATED THUNDERSTORMS LATER
ON THIS MORNING THROUGH THE EARLY AFTERNOON HOURS. MAY SEE A
DECREASE IN COVERAGE INTO THE MID TO LATE AFTERNOON HOURS AS THE
UPSTREAM RIDGE AMPLIFIES AND SHIFTS OVERHEAD. AS SUCH HAVE
MAINTAINED POPS IN THE ISOLATED TO SCATTERED CATEGORY AREAWIDE.

THIS RIDGING IS FORECAST TO SLIDE EASTWARD TONIGHT ALLOWING
NORTHERN AND CENTRAL UT TO COME UNDER THE INFLUENCE OF THE
UPSTREAM UPPER LOW...WHICH IS FORECAST TO PARK ITSELF ACROSS THE
INTERIOR PACIFIC NORTHWEST THROUGH WEDNESDAY. MOISTURE REMAINING
IN PLACE WILL PROVIDE SUFFICIENT INSTABILITY FOR CONVECTION EACH
DAY...AND EMBEDDED WAVES WITHIN A MEAN SOUTHWESTERLY FLOW ALOFT
SHOULD HELP ORGANIZE THIS ACTIVITY AND PROVIDE FOR BETTER
COVERAGE TUESDAY THROUGH WEDNESDAY.

.LONG TERM (AFTER 06Z THURSDAY)...A MEAN LONGWAVE TROUGH WILL REMAIN
IN PLACE INTO FRIDAY MORNING BEFORE BREAKING DOWN HEADING INTO THE
WEEKEND. PRIMARY FEATURE TO FOCUS ON REMAINS A MODERATELY STRONG MID
LEVEL SHORT WAVE PASSING THROUGH NORTHERN/EASTERN UTAH THURSDAY INTO
FRIDAY. GLOBAL MODELS HAVE REMAINED IN GOOD AGREEMENT BOTH MODEL TO
MODEL AND RUN TO RUN FOR THE LAST FEW SIGNIFYING RELATIVELY SHARP
CURVATURE...DECENT H7 CAA AND SOME JET SUPPORT WITH THE SHORT WAVE
THURSDAY. EXPECTING ANOTHER FAIRLY WIDESPREAD CONVECTIVE PRECIP
EVENT DURING THE DAY AS A RESULT...WITH A GRADUAL TAPERING TREND
FROM WEST TO EAST THURSDAY NIGHT.

DOWNSTREAM PROGRESSION OF THE AFOREMENTIONED SHORT WAVE WILL FINALLY
ALLOW A STRENGTHENING MID LEVEL RIDGE TO BUILD EAST THROUGH THE AREA
LATER FRIDAY THROUGH NEXT WEEKEND. H7 TEMPS AT KSLC ARE EXPECTED TO
CLIMB FROM +5 C FRIDAY INTO THE LOW TEENS SUNDAY AFTERNOON ALLOWING
TEMPS TO REACH THEIR HIGHEST LEVELS THUS FAR THIS SPRING. OPTED TO
TREND TEMPERATURES UP...FORGOING USE OF BIAS CORRECTED GUIDANCE IN
FAVOR OF RAW OUTPUT DUE TO THIS MORE NOTED PATTERN CHANGE.

&&

AVIATION...CIGS AT OR BELOW 6000FT AGL ASSOCIATED WITH PASSING
SHOWERS ARE EXPECTED TO BE MAINTAINED AT THE KSLC TERMINAL THROUGH
12Z BEFORE GRADUALLY THINNING AND LIFTING. A 20 PERCENT CHANCE
EXISTS THAT ISOLATED SHOWERS AND STORMS WILL IMPACT THE TERMINAL
THEREAFTER TODAY. PERIODIC CIGS AOB 6000FT AGL AND GUSTY ERRATIC
WINDS WILL BE THE PRIMARY IMPACTS WITH THESE CELLS...BUT ONLY A 10
PERCENT CHANCE THAT LIGHTNING WILL IMPACT THE TERMINAL.

&&

FIRE WEATHER...COOL AND UNSTABLE CONDITIONS WILL CONTINUE TODAY WITH
ISOLATED VALLEY SHOWERS/STORMS AND SCATTERED MOUNTAIN COVERAGE. A
STORM SYSTEM APPROACHING FROM THE NORTHWEST DURING THE TUESDAY
THROUGH WEDNESDAY TIMEFRAME IS EXPECTED TO INCREASE THE POTENTIAL OF
SHOWERS/STORMS AND AREAL COVERAGE OF WETTING RAINS THROUGH WEDNESDAY
NIGHT. THIS STORM SYSTEM IS EXPECTED TO PASS THROUGH THE DISTRICT
THURSDAY BRINGING AN ADDITIONAL POTENTIAL OF RELATIVELY WIDESPREAD
WETTING RAINS TO THE MAJORITY OF THE DISTRICT...ESPECIALLY NORTHERN
PORTIONS.

HIGH PRESSURE WILL FINALLY BUILD IN LATE THIS WEEK AND STRENGTHEN
THROUGH NEXT WEEKEND. DURING THAT TIME A MARKED WARMING/DRYING TREND
IS EXPECTED.

&&

&&

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

$$

SEAMAN/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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