Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 230846
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
246 AM MDT SUN AUG 23 2015

.SYNOPSIS...A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE REGION
AND PERSIST INTO EARLY NEXT WEEK. MOISTURE WILL SPREAD NORTHWARD
ACROSS THE AREA MIDWEEK...WITH A SERIES OF UPPER LEVEL
DISTURBANCES ALSO ROTATING ACROSS THE REGION.

&&

.SHORT TERM (THROUGH 12Z WEDNESDAY)...
WATER VAPOR LOOP SHOWS A RIDGE AMPLIFYING INTO THE GREAT BASIN
FROM THE SOUTHEAST. AMDAR 400-250MB WIND OBSERVATIONS SHOW A
80-125KT CYCLONIC JET FROM WESTERN CANADA INTO THE UPPER MIDWEST.
GOES/GPS/RAP/00Z SLC RAOB INDICATE THE PRECIPITABLE WATER VALUE
RANGES BETWEEN 0.10"-0.25" NORTHERN MOUNTAINS...TO 0.75"-1.10"
ACROSS THE SOUTHERN VALLEYS.

SMOKE WILL BECOME LESS EXTENSIVE OVER THE WEEKEND...AND SHOULD
DISSIPATE EARLY NEXT WEEK WITH THE RIDGE BUILDING IN FROM THE
SOUTHEAST.

MOISTURE CONTINUES TO INCREASE FROM SOUTH TO NORTH TODAY. HAVE
BUMPED UP POPS INTO SCATTERED CATEGORY ALONG THE SPINE OF THE
MOUNTAINS BASED ON NCAR WRF ENSEMBLE SIMULATED REFLECTIVITY OUTPUT
ALONG WITH THE LATEST HRRR-3KM. FLOW IS LIGHT WESTERLY SO ONLY
INDICATE A SMALL CHANCE FOR CONVECTION INTO THE UINTA BASIN AND
CASTLE COUNTRY. PROFILES SUGGEST LOCALLY GUSTY WINDS WILL BE THE
PRIMARY THREAT DUE TO DRY MICROBURSTS.

LOOKS LIKE WE DRY OUT A BIT MONDAY AS SOUTHWESTERLY FLOW ALOFT
DEVELOPS...TAPERING CONVECTIVE CHANCES DOWN ABOUT 10 PERCENT IN THE
MOUNTAINS.

GLOBAL MODELS STILL INDICATE A SHORTWAVE RIDES NORTH INTO UTAH
WITHIN THE RETURN FLOW TUESDAY NIGHT. HOWEVER MODELS HAVE STILL NOT
QUITE LATCHED ONTO TIMING AND PATH OF THIS FEATURE SO KEPT POPS
FAIRLY GENERAL AT THIS POINT. EXPECT WIDESPREAD MIDLEVEL CLOUDS LATE
TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO NORTH. GUSTY WINDS POSSIBLE
ON THE NORTHERN PERIPHERY OF THE CONVECTION...WITH A LOCALLY HEAVY
RAIN THREAT DEVELOPING IN TIME ESPECIALLY ACROSS THE SOUTH TUESDAY
NIGHT.

.LONG TERM (AFTER 12Z WEDNESDAY)...
THE MEDIUM RANGE PERIOD BEGINS WITH AN UPPER LEVEL HIGH SITUATED
OVER THE SOUTHERN PLAINS AND AN UPPER LEVEL TROUGH OFF OF THE
PACIFIC NW COAST. ECMWF...GFS....AND CANADIAN MODELS ARE ALL IN
AGREEMENT THAT WAVE ROTATING AROUND THE UPPER LEVEL HIGH LIFTS
NORTH THROUGH UTAH ON WEDNESDAY. WAVE SHOULD BE INTERACTING WITH
AMPLE MOISTURE AS IT LIFTS NORTH WITH THE GFS INDICATING THAT
PRECIPITABLE WATER VALUES WILL BE GREATER THAN 1" PRETTY MUCH
STATEWIDE ON WED. GIVEN THE PERSISTENCE OF THIS FEATURE IN RECENT
GUIDANCE AND THE AGREEMENT IN ALL THREE MODELS...HAVE INCREASED
POPS A BIT FROM FROM WED MORNING THROUGH WED EVENING. GIVEN THE
EXPECTATION OF EXTENSIVE CLOUD COVER AND DECENT COVERAGE OF
SHOWERS AND THUNDERSTORMS ON WED HAVE DROPPED TEMPERATURES DOWN A
BIT....ESPECIALLY ACROSS THE SOUTH.

THE FLOW ALOFT BECOMES MORE WESTERLY ON THURSDAY AND PRECIPITABLE
WATER VALUES DROP A BIT.  HOWEVER...MOISTURE WON`T SCOUR QUICKLY AND
WILL KEEP ISOLATED VALLEY POPS AND SCATTERED MOUNTAIN POPS FOR THU
AFTERNOON AND EVE. SOUTHWEST FLOW ALOFT LATE IN THE WEEK INTO THE
WEEKEND RESULTS IN A SLOW DRYING AND WARMING TREND INTO THE
WEEKEND. IN ADDITION...THE FLOW ALOFT INCREASES AS UPPER LEVEL
TROUGH MOVES INTO THE PAC NW WHICH COULD RESULT IN BREEZY
CONDITIONS FOR UTAH AND SOUTHWEST WYOMING.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT THE KSLC TERMINAL THROUGH
THE TAF PERIOD. SMOKE WILL PERSIST OVER THE AREA WITH VISIBILITY
OCCASIONALLY BEING REDUCED TO AROUND 6SM TODAY.  LIGHT SOUTHEAST
WINDS THIS MORNING WILL SWITCH TO THE NORTHWEST BETWEEN 1800 UTC AND
2000 UTC. THERE IS A 20 PERCENT CHANCE THAT THIS WIND SHIFT HOLDS
OFF UNTIL AFTER 2000 UTC.

&&

.FIRE WEATHER...GENERALLY LIGHT SOUTHWEST-WEST FLOW TODAY. WINDS MAY
BE LOCALLY GUSTY/ERRATIC NEAR SHOWERS...THOUGH THE MAJORITY OF THIS
ACTIVITY WILL DEVELOP IN THE SPINE OF THE MOUNTAINS THIS AFTERNOON
AND EVENING. LESSER COVERAGE IS EXPECTED SUNDAY WITH DRYING
DEVELOPING OVER THE WESTERN VALLEYS AS THE ENTIRE REGION WARMS WELL
INTO THE 90S.

A PATTERN CHANGE IS IN STORE FOR NEXT WEEK...WITH THE RIDGE OF HIGH
PRESSURE TAKING HOLD OF THE REGION. THIS MONSOONAL PATTERN WILL
SUPPORT AN INCREASE IN CLOUD COVER...CAPPING TEMPERATURES...RISING
HUMIDITY...AND AN INCREASE IN CONVECTIVE COVERAGE. COULD SEE SOME
GUSTY WINDS AT THE LEADING EDGE OF CONVECTION FROM SOUTH TO NORTH
LATE TUESDAY INTO TUESDAY NIGHT.

&&

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

&&

$$

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

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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