Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 281528
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
928 AM MDT MON JUL 28 2014

.SYNOPSIS...A VERY MOIST AIRMASS WILL BE OVER THE AREA TODAY AND
TUESDAY. EMBEDDED UPPER LEVEL DISTURBANCES WILL COMBINE WITH THE
MOISTURE TO BRING A WIDESPREAD THREAT OF PRECIPITATION TO THE
AREA.

&&

.DISCUSSION...HIGH CENTER AT 500 MB IS LOCATED OVER WYOMING THIS
MORNING...WHEN THE MONSOON HIGH GETS THAT FAR NORTH...OUR AREA
COMES UNDER MOIST EAST TO SOUTHEAST FLOW AND THE RESULT IS USUALLY
A LOT OF MOISTURE AND PRECIP. ALL THAT APPEARS TO BE THE CASE
TODAY WITH PRECIPITABLE WATER VALUES OF AN INCH OR MORE OVER
NEARLY THE ENTIRE FORECAST AREA. SCATTERED LIGHT SHOWERS AND
EXTENSIVE CLOUD COVER ALREADY OCCURRING.

AT 12Z A CLOSED UPPER LOW AT 500 MB WAS LOCATED OVER SOUTHERN CA
AND A TROUGH AXIS/DEFORMATION ZONE EXTENDED FROM THIS LOW TO THE
NORTHEAST TO ANOTHER FEATURE IN EXTREME NORTHEAST NV. THESE
FEATURES MOVE VERY SLOWLY TO THE EAST OVER THE NEXT TWO DAYS.
EXPECT COMBINATION OF DYNAMIC LIFT AND AMPLE MOISTURE TO PRODUCE
WIDESPREAD SHOWERS WITH EMBEDDED HEAVY RAIN AND THUNDERSTORMS THIS
AFTERNOON AND CONTINUING INTO THE NIGHT.

MODELS SUGGEST UPPER TROUGH AND ASSOCIATED RAIN MAY CONTINUE MUCH
OF THE NIGHT OVER NORTHERN UTAH...WITH MUCH
COOLER...CLOUDY...SHOWERY CONDITIONS THROUGH MUCH OF TUESDAY
ACROSS THE NORTH. WILL WAIT FOR 12Z RUNS TO CONFIRM THIS
SCENARIO...BUT COULD NEED UNUSUALLY HIGH POPS OVERNIGHT ACROSS THE
NORTH...ALTHOUGH RAINFALL TOTALS WOULD LIKELY BE LIGHT. CURRENT
FORECAST ALREADY ALONG THESE LINES...BUT COULD GO FURTHER IN THIS
DIRECTION IF LATER MODELS CONTINUE TO SHOW THE SAME PATTERN.

IN SHORT TERM...LATEST HRRR SUGGESTS CLOUD COVER WILL DIMINISH
LATE THIS MORNING AND CONVECTION WILL LIGHT UP OVER SOUTH/CENTRAL
UTAH 18 TO 19 UTC AND THEN EXPAND THROUGH THE REST OF THE
AFTERNOON. HEAVY RAIN POSSIBLE JUST ABOUT ANYWHERE IN THE STATE
TODAY AND WILL HAVE TO WATCH BURN SCARS AND SLOT CANYONS VERY
CLOSELY. EXISTING FLASH FLOOD WATCH IS MAINLY FOR CANYON COUNTRY.

NO CHANGES TO CURRENT FORECAST AT THIS TIME.

&&

.AVIATION...SOUTHEAST WINDS AT THE SLC TERMINAL WILL SWITCH TO THE
NORTHWEST BETWEEN 18-19Z. THERE IS A 20 PERCENT CHANCE OF
THUNDERSTORMS IN THE VICINITY OF THE TERMINAL AFTER 18Z THROUGH
02Z...WITH THE POSSIBILITY OF REDUCED VISIBILITY AND CEILINGS
APPROACHING 6000 FT AGL DURING THESE EVENTS. ANY THUNDERSTORMS COULD
PRODUCE GUSTY AND ERRATIC WINDS.

&&

.FIRE WEATHER...DEEP MOISTURE HAS SPREAD ACROSS THE ENTIRE DISTRICT
ALLOWING SURFACE HUMIDITY VALUES TO CLIMB OVER THE LAST 24
HOURS...ESPECIALLY ACROSS THE FAR NORTH. WITH THIS MOISTURE IN PLACE
EXPECTING SIGNIFICANT SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP
THIS AFTERNOON/EVENING DISTRICT WIDE BRINGING A FAIRLY HIGH
LIKELIHOOD OF WETTING RAINS TO THE AREA. SHOWER AND STORM ACTIVITY
WILL TREND TO DISSIPATE SOUTH TO NORTH TONIGHT THROUGH
TOMORROW...WITH A SLIGHT DRYING TREND IN HUMIDITY EXPECTED ACROSS
THE SOUTH TOMORROW. THIS DRYING TREND WILL SPREAD NORTH WEDNESDAY
BUT SUFFICIENT MOISTURE WILL REMAIN ACROSS THE REGION FOR AFTERNOON
AND EVENING MOUNTAIN THUNDERSTORMS EACH DAY THROUGH THE END OF THE
WEEK. WETTING RAIN POTENTIAL WILL BE ON THE DECREASE HOWEVER.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR UTZ016-019>021-
     517-518.

WY...NONE.
&&

$$

PUBLIC...DUNN
FIRE WEATHER...MERRILL
AVIATION...VERZELLA

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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