Severe Thunderstorm Warning 71, NWS Salt Lake City, UT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1021 AM MDT MON AUG 15 2011

.SYNOPSIS...A WEATHER DISTURBANCE WILL CROSS NORTHERN UTAH TODAY.
OTHERWISE A DRIER AIRMASS WILL BEGIN TO MOVE BACK INTO THE REGION
FROM THE WEST THIS AFTERNOON...WITH THE DRYING TREND CONTINUING
THROUGH MIDWEEK.

&&

.DISCUSSION...SATELLITE DERIVED PWATS INDICATE A FURTHER INTRUSION
OF DRY AIR ACROSS THE SOUTHWEST...DEEPER MOISTURE SOME 1 TO 2
STANDARD DEVIATIONS ABOVE NORMAL RESIDE IN THE NORTH AND EAST. 12Z
KSLC RAOB INDICATES 1.00 INCH OF PWAT IN PLACE WITH PRONOUNCED
BOUNDARY LAYER STABILITY IN WAKE OF THE RAINFALL THAT OCCURRED
OVERNIGHT. THIS SAID...SIGNIFICANT POTENTIAL INSTABILITY EXISTS
ACROSS THE NORTH AND EAST AND INCREASED CONVECTION IS LIKELY AS
THE LOW LEVELS HEAT UP THIS AFTERNOON.

A SHORT WAVE OVER NORTHERN CALIFORNIA COUPLED WITH AN ASSOCIATED
JET STREAK WILL FUEL BROAD LIFT ACROSS NORTHERN UTAH FURTHER
ENHANCING POTENTIAL FOR SHOWERS AND THUNDERSTORMS THROUGH THIS
EVENING. FOCUS OF SHIFT WILL BE HEAVILY WEIGHTED TOWARDS
MONITORING SAID CONVECTIVE DEVELOPMENT AS VARIABLES ARE IN PLACE FOR SOME
DECENT ORGANIZATION LATER TODAY. AN ISOLATED SEVERE STORM OR TWO
ARE POSSIBLE GIVEN SHEAR PROFILES...MOISTURE AND MARGINAL SYNOPTIC
FORCING.

AFOREMENTIONED DRY INTRUSION WILL SIGNIFICANTLY HAMPER THE
POTENTIAL FOR CONVECTION OVER THE SOUTHWESTERN THIRD OF THE STATE
TODAY. WILL BE MONITORING WINDS AND RH ACROSS THE WESTERN VALLEYS
AS CURRENT THINKING POINTS TOWARDS ISOLATED CRITICAL FIRE WEATHER
CONDITIONS ACROSS THE FAR WESTERN VALLEYS THIS AFTERNOON. DRY
INTRUSION WILL CONTINUE A NORTHEAST PROGRESSION OVER THE NEXT 24
HOURS ESSENTIALLY SQUELCHING ANY CONVECTIVE POTENTIAL TUESDAY
OUTSIDE OF ISOLATED TERRAIN BASED BUILDUPS OVER THE EAST. WEATHER
WILL REMAIN BENIGN THROUGH THE MIDWEEK PERIOD AS HIGH PRESSURE
ONCE AGAIN BUILDS IN OVERHEAD.

GOING FORECAST REMAINS ON TRACK...NO UPDATES AT THIS TIME.

&&

.AVIATION...ANTICIPATING OPERATIONAL WEATHER CONCERNS WILL BECOME
MORE SIGNIFICANT LATE THIS AFTERNOON AND THIS EVENING AS SHOWERS
AND THUNDERSTORMS ARE ONCE AGAIN EXPECTED. THE WINDOW FOR THE
HIGHEST POTENTIAL FOR CONVECTION FUELING GUSTY OUTFLOW WINDS AND A
20 PERCENT CHANCE OF THUNDERSTORMS AT THE TERMINAL LIES IN THE
22-05Z TIMEFRAME. OUTSIDE OF A WIND SWITCH BETWEEN 19-20Z SHORT
TERM CONCERNS REMAIN LIMITED AND VFR WILL PREVAIL.

&&

.FIRE WEATHER...DRY AIR WILL CONTINUE TO MAKE ITS WAY INTO THE
STATE...WITH RH VALUES BOTTOMING OUT TOMORROW AFTERNOON. GUSTY WINDS
ARE EXPECTED OVER THE NORTHERN HALF OF THE STATE THIS AFTERNOON.
WHILE ISOLATED HAZARDOUS FIRE WEATHER CONDITIONS ARE EXPECTED TO
DEVELOP OVER THE NORTHWEST CORNER OF THE STATE...DO NOT EXPECT
CONDITIONS TO BE WIDESPREAD DUE TO MARGINAL MOISTURE. AS A
RESULT...WILL HOLD OFF ON ISSUING A RED FLAG WARNING.

CONVECTION IS EXPECTED TO DEVELOP AGAIN THIS AFTERNOON...MAINLY EAST
OF I-15 WHERE THE MOISTURE IS DEEPEST. STORMS ARE EXPECTED TO BE THE
STRONGEST ACROSS NORTHERN UTAH. WITH THE AMOUNT OF MOISTURE
PRESENT...WETTING RAIN WILL LIKELY ACCOMPANY THESE STORMS.
ADDITIONALLY...WINDS WILL BE GUSTY AND ERRATIC IN THE VICINITY OF
ANY THUNDERSTORMS THAT FORM.

RH VALUES WILL DROP BELOW CRITICAL LEVELS TOMORROW AFTERNOON...BUT
WINDS WILL BE MUCH LIGHTER. MOISTURE WILL RETURN TO THE STATE
BEGINNING THURSDAY.

&&

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

MERRILL/HOSENFELD

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
322 AM MDT MON AUG 15 2011

UTZ001>016-019>021-517-518-WYZ021-161000-
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-
322 AM MDT MON AUG 15 2011

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE ACROSS
NORTHERN PORTIONS OF THE OUTLOOK AREA TODAY...AS A PASSING WEATHER
DISTURBANCE INTERACTS WITH LINGERING MOISTURE. STRONG GUSTY
WINDS...BRIEF HEAVY RAIN...SMALL HAIL AND DEADLY LIGHTNING ARE ALL
POSSIBLE WITH THESE STORMS.

ELSEWHERE DRIER AIR WILL SPREAD INTO SOUTHWEST UTAH TODAY...AND
ALONG WITH AN INCREASE IN WINDS...MAY BRING ISOLATED POCKETS OF
HAZARDOUS FIRE WEATHER CONDITIONS TO WEST CENTRAL AND SOUTHWEST
UTAH THIS AFTERNOON.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A DRYING TREND IS FORECAST HEADING INTO MID WEEK...WITH ONLY A
FEW STORMS POSSIBLE OVER THE NORTHEASTERN MOUNTAINS TUESDAY...AND
DRY CONDITIONS FORECAST FOR THE ENTIRE AREA WEDNESDAY.

A THREAT OF SHOWERS AND THUNDERSTORMS WILL RETURN TO SOUTHWEST
UTAH THURSDAY THEN SPREAD OVER MOST OF THE OUTLOOK AREA BY THE
END OF THE WEEK.

.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)