Flash Flood Warning 99, NWS Salt Lake City, UT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1040 PM MDT TUE SEP 10 2013

.SYNOPSIS...A SLOW MOVING UPPER LOW PRESENTLY IN ARIZONA WILL DRIFT
NORTHWARD INTO THE GREAT BASIN WEDNESDAY AND REMAIN OVER THE AREA
INTO MID FRIDAY. A VERY MOIST AIRMASS WILL ACCOMPANY THE STORM AND
SPREAD RAIN OVER THE ENTIRE FORECAST AREA OVER THE NEXT FEW DAYS.

&&

.DISCUSSION...UPPER LEVEL LOW OVER ARIZONA DRIFTING VERY SLOWLY TO
THE NORTH THIS EVENING. DEEP MOISTURE CONTINUES TO STREAM NORTH
ALONG THE EASTERN PERIPHERY OF THE LOW AND INTO CENTRAL AND
SOUTHERN UTAH. WITH MID LEVEL CONVERGENCE AND MODEST JET SUPPORT
DEEP LIFT CONTINUES TO SUPPORT WIDESPREAD PRECIPITATION ACROSS
MUCH OF SOUTHERN UTAH. NUMEROUS REPORTS IN EXCESS OF AN INCH OF
RAIN HAVE COME IN THROUGH THE DAY. RUNOFF FROM THE WIDESPREAD
PRECIPITATION THIS AFTERNOON AND EVENING HAS RESULTED IN NORMALLY
DRY WASHES RUNNING FULL AS WELL AS FLOODING OF SLOT CANYONS AND
STREAM ACROSS SOUTHERN UTAH. RIVER LEVELS HAVE ALSO COME UP QUITE
A BIT THIS EVENING...INCLUDING THE PARIA...ESCALANTE...AND THE
DIRTY DEVIL. ANTICIPATE FLOODING TO CONTINUE OVERNIGHT EVEN IF
AREAL COVERAGE OF PRECIPITATION DIMINISHES AS RUNOFF WILL CONTINUE.
ACROSS THE NORTH EXPECTED MORE SCATTERED COVERAGE OF SHOWERS
OVERNIGHT. ALSO..WITH EASTERLY GRADIENT IN PLACE EXPECT THAT WE
WILL SEE BREEZY EASTERLY WINDS CONTINUE NEAR CANYON MOUTHS ALONG
THE WASATCH FRONT THROUGH THE NIGHT.

700 HPA LOW WILL DRIFT SLOWLY NORTH ON WEDNESDAY AND ANTICIPATE
WIDESPREAD PRECIPITATION TO DEVELOP ACROSS SOUTHERN UTAH ONCE
AGAIN. WITH LARGE SCALE LIFT UNDERWAY AND PRECIPITABLE WATER
VALUES IN EXCESS OF AN INCH HEAVY RAIN IS EXPECTED FOR MANY OF THE
SAME AREAS IN CENTRAL AND SOUTHERN UTAH AND FLASH FLOOD WATCH
CONTINUES THROUGH WEDNESDAY EVENING. AS THE LOW LIFTS NORTH
EXPECTED INCREASED COVERAGE OF PRECIPITATION TO DEVELOP ACROSS
THE NORTH ALTHOUGH PORTIONS OF THE WASATCH FRONT MAY BE SHADOWED
WITH LARGE SCALE EASTERLY FLOW IN PLACE. STILL ANTICIPATE
A SIGNIFICANT INCREASE IN COVERAGE ACROSS NORTHERN UTAH BY
WEDNESDAY AFTERNOON.

&&

.AVIATION...OPERATIONAL WEATHER CONCERNS AT THE KSLC TERMINAL ARE
EXPECTED TO REMAIN MINIMAL TONIGHT. SOUTHEAST WINDS WILL CONTINUE TO
PREVAIL WITH ANY CIGS REMAINING WELL ABOVE 7000FT AGL.

RAIN SHOWERS AND THE POTENTIAL FOR PASSING THUNDERSTORMS WILL
INCREASE THROUGHOUT TOMORROW FROM THE SOUTH AND EAST. AT THIS TIME
THE PRIMARY IMPACTS LOOK TO BE BRIEF CIGS AT OR BELOW 6000FT
AGL...MODERATE RAIN SHOWERS AND ERRATIC WINDS. THESE IMPACTS ARE
MOST LIKELY TO OCCUR AFTER 18Z WITH ONLY A 30 PERCENT CHANCE OF
HAPPENING IN THE 14-18Z WINDOW.

&&

.FIRE WEATHER...FROM PREVIOUS AFD ISSUED AT 342 PM MDT
DEEP MOISTURE WILL REMAIN ACROSS THE STATE THROUGH THIS
WEEKEND...RESULTING IN WIDESPREAD WETTING RAIN THROUGH THE
WEEKEND. FIRE WEATHER CONCERNS ARE MINIMAL...AS RH VALUES WILL
REMAIN ABOVE AVERAGE AND WINDS WILL BE LIGHT. THUNDERSTORMS ARE
EXPECTED TO DEVELOP IN THE AFTERNOON ACROSS MUCH OF THE STATE INTO
THE WEEKEND.

&&

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...FLASH FLOOD WATCH THROUGH WEDNESDAY EVENING FOR
     UTZ010-012>014-016-019>021-517-518.

WY...NONE.
&&

PUBLIC...GRAHAM
FIRE WEATHER...HOSENFELD
AVIATION...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)

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
609 AM MDT TUE SEP 10 2013

UTZ001>016-019>021-517-518-WYZ021-111200-
CACHE VALLEY/UTAH PORTION-NORTHERN WASATCH FRONT-
SALT LAKE AND TOOELE VALLEYS-SOUTHERN WASATCH FRONT-
GREAT SALT LAKE DESERT AND MOUNTAINS-WASATCH MOUNTAIN VALLEYS-
WASATCH MOUNTAINS I-80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80-
WESTERN UINTA MOUNTAINS-WASATCH PLATEAU/BOOK CLIFFS-
WESTERN UINTA BASIN-CASTLE COUNTRY-SAN RAFAEL SWELL-
SANPETE/SEVIER VALLEYS-WEST CENTRAL UTAH-SOUTHWEST UTAH-
UTAHS DIXIE AND ZION NATIONAL PARK-SOUTH CENTRAL UTAH-
GLEN CANYON RECREATION AREA/LAKE POWELL-CENTRAL MOUNTAINS-
SOUTHERN MOUNTAINS-SOUTHWEST WYOMING-
609 AM MDT TUE SEP 10 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF
UTAH AND SOUTHWEST WYOMING.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS WILL PERSIST ACROSS THE SOUTHERN AND
EASTERN OUTLOOK AREA TODAY AND SPREAD INTO THE NORTHWEST THROUGH
THE DAY. THESE SHOWERS WILL CONTINUE OVER MOST AREAS TONIGHT.

HEAVY RAIN IS LIKELY WITH SOME OF THE STORMS OVER ABOUT THE
SOUTHEASTERN TWO THIRDS OF THE AREA AND THIS WILL GENERATE LOCAL
FLASH FLOODING THROUGH THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS MOST OF THE
OUTLOOK AREA WEDNESDAY THROUGH THURSDAY ALONG WITH A THREAT OF
HEAVY RAIN AND LOCAL FLASH FLOODING. SHOWERS WILL GRADUALLY
TAPER OFF FRIDAY THROUGH SATURDAY.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

FOR INFORMATION ON POTENTIAL TRAVEL IMPACTS VISIT...
HTTP://WWW.UDOTTRAFFIC.UTAH.GOV/ROADWEATHERFORECAST.ASPX