Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 311011
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
411 AM MDT THU JUL 31 2014

.SYNOPSIS...A WEAK DISTURBANCE WILL MOVE OUT OF NEVADA AND INTO
THE NORTHERN HALF OF UTAH FOR LATER TODAY THROUGH EARLY FRIDAY.
HIGH PRESSURE ALOFT WILL STRENGTHEN ACROSS THE INTERIOR WEST OVER
THE WEEKEND. A STRONGER WEATHER DISTURBANCE WILL LIFT NORTH
THROUGH THE GREAT BASIN LATE SUNDAY THROUGH MONDAY.

&&

.SHORT TERM (UNTIL 06Z MONDAY)...THE AIR MASS ACROSS MUCH OF UTAH
REMAINS PRIMED FRO CONVECTIVE ACTIVITY AGAIN TODAY. PWAT VALUES
REMAIN FAIRLY HIGH ACROSS WESTERN/SOUTHERN UTAH...WITH MODEST
DRYING NOTED IN RELATIVELY LOWER PWAT VALLEYS ACROSS THE NORTHEAST
EARLY THIS MORNING.

THE POORLY DEFINED VORTICITY MAX IN THE WATER VAPOR IMAGERY OVER
CENTRAL NEVADA WILL BECOME THE DRIVE FORCING FOR A NEW ROUND OF
CONVECTION THIS AFTERNOON/EVENING. WEAK MOISTURE CONVERGENCE BELOW
500 MB COUPLED WITH DYNAMIC LIFT FROM THE VORTICITY MAX SHOULD
GENERATE CONVECTION ACROSS NORTHWEST UTAH EARLY...WITH THIS
ACTIVITY EXPANDING SLOWLY EASTWARD DURING THE AFTERNOON. GOOD
HEATING EARLY ON SHOULD HELP TO DESTABILIZE THE AIR
MASS...LEADING TO FAIRLY STRONG AND SLOW-MOVING CONVECTION ACROSS
CENTRAL AND NORTHEAST UTAH. THE VORTICITY MAX WILL SLOW
CONSIDERABLY AS IT MOVES THROUGH UTAH. AS SUCH SCATTERED
CONVECTION WILL LIKELY LINGER INTO THE EVENING...THEN PERSIST
ACROSS NORTHEAST UTAH OVERNIGHT AND INTO EARLY FRIDAY.

MOSTLY CLEAR SKIES EARLY ON SHOULD ALLOW FOR CONVECTION TO GET
GOING OVER THE HIGHER SOUTHERN TERRAIN BY LATE THIS MORNING. HARD
TO FIND ANY FEATURE TO GENERATE ORGANIZED LIFT AT THIS TIME...SO
WILL KEEP THE AREAL COVERAGE A BIT LOWER ACROSS THE SOUTHERN ZONES
THIS AFTERNOON/EARLY EVENING.

STRENGTHENING OF THE UPPER RIDGE OVER UTAH FRIDAY NIGHT/SATURDAY
SHOULD PUT A DAMPER ON SHOWER/THUNDERSTORM ACTIVITY ON SATURDAY.
NOT LOOKING AT ANY STRONG DRYING OVER THE WEEKEND...WITH DIURNAL
MOUNTAIN CONVECTION STILL LOOKING GOOD AT THIS POINT.

THE EASTERLY WAVE MOVING ALONG THE ARIZONA/MEXICO BORDER EARLY IN
THE WEEKEND WILL TURN THE CORNER NORTHWARD THROUGH WESTERN ARIZONA
EARLY SUNDAY. THIS FEATURE WILL REESTABLISH THE MOISTURE TAP OUT
OF NORTHERN MEXICO/SOUTHERN ARIZONA AS IT MOVES NORTH NEAR THE
UTAH/NEVADA BORDER SUNDAY NIGHT. HAVE INCREASED POPS HEADING INTO
LATE SUNDAY/SUNDAY EVENING WITH THE LEADING PUSH OF THIS NEXT
MONSOONAL SURGE.

&&

.LONG TERM (AFTER 06Z MONDAY)...THE LONG TERM FORECAST PERIOD BEGINS
WITH THE CONTINUATION OF A STRONG MONSOONAL SURGE ACROSS SOUTHERN
UTAH...REACHING NORTHERN UTAH BY MONDAY MORNING.

A DISTURBANCE WILL SLOWLY MOVE NORTHWARD ON THE WESTERN PERIPHERY OF
HIGH PRESSURE PARKED OVER THE WESTERN UNITED STATES MONDAY. LONG
RANGE MODELS THAN BEGIN TO DIFFER ON THE SPEED AND LOCATION OF THIS
DISTURBANCE AFTER MONDAY. THE GFS SHUNTS THE DISTURBANCE OFF TO THE
NORTH AND EAST BY TUESDAY...WHILE THE EC OFFERS A MORE SPLIT
SOLUTION...KEEPING A PORTION OF THE SHORTWAVE STUCK IN THE WEAKER
FLOW OVER THE CWA. WITH THE MORE PROGRESSIVE SOLUTION...THE GFS
BRINGS AN END TO THE MONSOONAL SURGE OVER UTAH BY TUESDAY MORNING.
ON THE OTHER HAND...THE EC KEEPS DEEP MOISTURE OVER THE CWA THROUGH
WEDNESDAY MORNING.

THIS WILL HAVE SIGNIFICANT IMPLICATIONS FOR THE FORECAST AFTER
MONDAY...WITH THE EC FAVORING A MUCH WETTER PERIOD THROUGH AT LEAST
LATE TUESDAY. HAVE NOTED THAT THE MODELS HAVE TENDED TO TRY TO END
MONSOONAL PUSHES TOO EARLY OVER THE PAST FEW WEEKS. DECIDED TO LEAN
MORE TOWARD THE EC SOLUTION WITH A WETTER...COOLER PERIOD LONGER
THAN THE CURRENT GFS WOULD INDICATE. NEEDLESS TO SAY...CONFIDENCE IN
THIS PORTION OF THE FORECAST IS LOWER THAN AVERAGE.

&&

.FIRE WEATHER...SUFFICIENT MOISTURE REMAINS IN PLACE ACROSS THE
DISTRICT TODAY TO DEVELOP ANOTHER ROUND OF CONVECTION ACROSS MUCH OF
THE STATE WITH THE HIGHEST THREAT ACROSS THE HIGHER TERRAIN. GUSTY
AND ERRATIC WINDS WILL BE POSSIBLE NEAR ANY THUNDERSTORMS.
CONDITIONS WILL DRY OUT A BIT MORE FRIDAY...DECREASING THE COVERAGE
OF ANY CONVECTION TO MAINLY THE HIGHER TERRAIN. EXPECT THE
BEGINNINGS OF ANOTHER MONSOONAL SURGE WILL START TO INCREASE THE
CHANCE OF CONVECTION ACROSS THE SOUTHWEST ON SATURDAY. THIS DEEP
MOISTURE WILL SPREAD FURTHER NORTH AND EAST SUNDAY AND REMAIN ACROSS
MUCH OF THE DISTRICT INTO EARLY NEXT WEEK.

&&

.AVIATION...EXPECT WINDS TO SHIFT TO THE NORTH TO NORTHWEST EARLY
TODAY...BETWEEN 16-18Z WITH A 20 PERCENT CHANCE WINDS WILL SHIFT AS
EARLY AS 15Z. THERE IS A 20 PERCENT CHANCE OF SHOWERS/THUNDERSTORMS
IMPACTING THE TERMINAL THIS AFTERNOON BETWEEN 20Z-01Z. ANY
SHOWERS/THUNDERSTORMS MAY PRODUCE STRONG GUSTY AND ERRATIC WINDS AT
THE TERMINAL.

&&

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

$$

SHORT TERM...CONGER
LONG TERM/FIRE WEATHER/AVIATION...KRUSE

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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