Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 152101
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
301 PM MDT TUE JUL 15 2014

.SYNOPSIS...A DISTURBANCE MOVING THROUGH THE NORTHERN ROCKIES
WILL INTERACT WITH MONSOON MOISTURE OVER CENTRAL AND SOUTHERN UTAH
TODAY. A GENERALLY DRIER NORTHWEST FLOW WILL BECOME ESTABLISHED
OVER MOST OF THE AREA WEDNESDAY AND THURSDAY.

&&

.DISCUSSION...AFTERNOON SURFACE ANALYSIS INDICATES A FAIRLY WEAK
BOUNDARY IS CURRENTLY LOCATED FROM ROUGHLY SOUTH OF WENDOVER TO
UTAH COUNTY. THIS BOUNDARY MAY MOVE A BIT FURTHER SOUTH OVER THE
REMAINDER OF THE AFTERNOON. CONVECTION HAS DEVELOP SOUTH OF THIS
BOUNDARY ACROSS PORTIONS OF SOUTHERN UTAH.

DUAL POL RADAR DATA FROM KICX INDICATE MANY OF THESE STORMS ARE
PRODUCING VERY HEAVY RAINFALL AND UP TO MARBLE SIZED HAIL.
CELL/OUTFLOW MERGERS HAVE PRODUCED VERY HEAVY RAINFALL...ALTHOUGH
MOST OF THIS HEAVY RAINFALL HAS OCCURRED OVER AREAS AT A LOW
THREAT OF FLASH FLOODING. THE MAIN EXCEPTION IS CONVECTION OVER
THE SULPHUR CREEK AREA IN/NEAR CAPITOL REEF NATIONAL PARK...WHICH
IS ESPECIALLY VULNERABLE TO FLASH FLOODING. A WARNING HAS BEEN
ISSUED FOR THIS AREA.

AS FOR THE REMAINDER OF THE AFTERNOON AND EVENING...IN THE WAKE
OF THIS BOUNDARY ACROSS THE NORTH...EXPECT ENOUGH STABILITY TO
KEEP THE THREAT OF THUNDERSTORMS MINIMAL. SOUTH OF THIS
BOUNDARY...DEEP MOISTURE WILL ALLOW FOR CONTINUED DEVELOPMENT OF
SHOWERS AND THUNDERSTORMS. THE HEAVIEST RAINFALL WILL BE IN AREAS
THAT MAINTAIN CONVECTIVE DEVELOPMENT...PARTICULARLY THROUGH THE
PROPAGATION/MERGER OF OUTFLOW BOUNDARIES AND CELL MERGERS.

GIVEN THE THREAT FOR HEAVY RAINFALL...A FLASH FLOOD WATCH REMAINS
IN EFFECT FOR CENTRAL AND SOUTHERN UTAH. THE MOST CONCERNING
LOCATIONS FOR FLASH FLOODING INCLUDE DRY WASHES...SLOT CANYONS AND
SMALL STREAMS IN STEEP TERRAIN AS WELL AS POSSIBLE DEBRIS FLOWS
NEAR RECENT BURN SCARS.

SHOWERS AND THUNDERSTORMS WILL SLOWLY DECREASE IN
COVERAGE/INTENSITY THIS EVENING INTO THE OVERNIGHT HOURS. ANOTHER
ROUND OF CONVECTION IS POSSIBLE AS THE BOUNDARY MOVES FURTHER
NORTH TOMORROW AFTERNOON. FLASH FLOODING WILL AGAIN BE POSSIBLE
ACROSS THE SOUTHERN THIRD OR SO OF UTAH. WILL LET FUTURE SHIFTS
ADDRESS THE POSSIBILITY OF A FLASH FLOOD WATCH FOR THESE LOCATIONS
FOR WEDNESDAY.

&&

.FIRE WEATHER...A MOIST AIR MASS OVER CENTRAL AND SOUTHERN UTAH WILL
GRADUALLY GET NUDGED SOUTHWARD WEDNESDAY AND THURSDAY.
HOWEVER...SCATTERED WETTING RAINS ARE EXPECTED THIS AFTERNOON AND
EVENING. THE DRY AIR MASS HAS MOVED INTO NORTHERN UTAH AND WILL
SPREAD INTO CENTRAL AND SOUTHERN UTAH WEDNESDAY AND THURSDAY. THE
NORTHWEST FLOW IS EXPECTED TO BE STRONG ENOUGH OVER EAST CENTRAL
UTAH WEDNESDAY AFTERNOON FOR A RED FLAG WARNING TO BE ISSUED FOR THE
ZONE 489 BELOW 7500 FEET. THE DOWN SLOPE COMPONENT IS EXPECTED TO
DRY THE AIR CONSIDERABLY TO ALLOW RELATIVE HUMIDITY VALUES TO DIP
BELOW 15 PERCENT. THE FLOW ALOFT REMAINS NORTHWEST THROUGH THURSDAY
BUT THEN SHIFT TO WEST SOUTHWEST FRIDAY INTO SATURDAY ALLOWING SOME
MOISTURE TO INCREASE. THIS MOISTURE INCREASE WILL BE SHORT LIVED AS
A DRIER AIR MASS MOVES IN FROM THE SOUTHWEST FOR SUNDAY INTO
MONDAY.

&&

.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGHOUT THE
TAF PERIOD. NORTHWEST WINDS ARE EXPECTED TO SHIFT TO SOUTHEAST
BETWEEN 03-05Z. OCCASIONAL GUSTS TO THE MID TEENS POSSIBLE UNTIL
02Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...RED FLAG WARNING FROM 1 PM TO 10 PM MDT WEDNESDAY FOR UTZ489.

     FLASH FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR UTZ010-012-
     013-019>021-517-518.

WY...NONE.
&&

$$

KRUSE/STRUTHWOLF/YOUNG

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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