Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 030412
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1012 PM MDT SUN AUG 2 2015

.SYNOPSIS...A WEAK UPPER LEVEL LOW PRESSURE SYSTEM WILL SLOWLY
TRACK SOUTH TO NORTH ACROSS THE REGION TONIGHT THROUGH EARLY
MONDAY. A DRIER SOUTHWESTERLY FLOW WILL FOLLOW FOR MIDWEEK.

&&

.SHORT TERM (UNTIL 12Z WEDNESDAY)...ANIMATED WATER VAPOR IMAGERY
BEGINNING TO SUGGEST THAT A CONSOLIDATED UPPER LOW IS FORMING
ACROSS CENTRAL UTAH LATE THIS EVENING. THIS DEVELOPMENT FITS WITH
THE MODEL GUIDANCE WHICH BRINGS THIS FEATURE FROM CENTRAL UTAH
INTO NORTHERN UTAH LATER TONIGHT/EARLY MONDAY. DEEP LAYER MOISTURE
AND SOLID DYNAMIC LIFT SHOULD BRING SOME PRECIP ACROSS THE NORTH
THROUGH AT LEAST MONDAY MORNING. RESIDUAL MOISTURE TRAILING THE
UPPER LOW WILL LIKELY FUEL DIURNAL CONVECTION ACROSS SOUTHERN AND
CENTRAL UTAH MONDAY AFTERNOON AND EARLY EVENING.

HIGH PRESSURE ALOFT WILL SETTLE INTO UTAH BY TUESDAY...THEN SHIFT
OFF TO THE EAST MIDWEEK. A SIGNIFICANTLY DRIER SOUTHWEST FLOW
ALOFT WILL FOLLOW THE PASSING RIDGE BEGINNING LATE TUESDAY.

.PREVIOUS LONG TERM (AFTER 12Z WEDNESDAY)...THE SUBTROPICAL RIDGE
AXIS CENTERED OVER THE AZ/NM BORDER SUBTLY SHIFTS EASTWARD ON
WEDNESDAY AS A LOW AMPLITUDE TROUGH SNEAKS TOWARD NORTHERN
UTAH...PROMOTING A RELATIVELY DRY SOUTHWESTERLY FLOW ALOFT. A WEAK
SHORTWAVE EMBEDDED WITHIN THE FLOW ACCOMPANIED BY INCREASING PWAT
WILL PROVIDE AMPLE DYNAMICS TO ENCOURAGE AFTERNOON AND EVENING
CONVECTION IN NORTHERN UTAH. THIS FEATURE ALSO COOLS DOWN 7H
TEMPERATURES A FEW DEGREES... DELIVERING TEMPS ABOUT 5 DEGREES
BELOW SEASONAL NORMS FOR THE NORTHERN HALF OF THE STATE. HAVE
LOWERED APPROPRIATE THURSDAY MAX TEMPS A BIT TO REFLECT THIS.
LINGERING INSTABILITY OVER THE UINTAS MAY BE THE ONLY CHANCE FOR A
DOLLOP OF CONVECTIVE ACTIVITY ON THURSDAY AFTERNOON.

FRIDAY TEMPS WARM RAPIDLY AHEAD OF AN ENCROACHING AND DEEPENING LOW
PRESSURE SYSTEM SWINGING INTO CALIFORNIA. MODELS DIVERGE AT THIS
POINT ON TIMING AND IMPACT OF THIS LOW AS IT PROGRESSES TOWARD UTAH.
THE GFS HAS REMAINED STAUNCH IN DELIVERING PRECIP INTO THE CWA BY
FRIDAY...WHILE THE ECMWF REMAINS SLOWER...LESS MOIST AND LESS
EXTENSIVE IN COVERAGE. IN EITHER CASE...EXPECTING MIDLEVEL SOUTHWEST
WINDS TO RAMP UP BY FRIDAY EVENING ACROSS MUCH OF THE STATE. HAVE
INTRODUCED POPS IN SOUTHERN UTAH BY FRIDAY 18Z AND EXTENDED THEM A
BIT FURTHER NORTH ON SATURDAY TO GENTLY NUDGE TOWARD GFS SOLUTION.

DRIER AIR RAPIDLY REPLACES THE EXITING SYSTEM SATURDAY INTO
SUNDAY...BRINGING A ZONAL UPPER LEVEL FLOW AND QUIET END TO THE
WEEKEND.

&&

.AVIATION...SURFACE HIGH PRESSURE OVER CENTRAL UTAH AND A
SOUTHEAST FLOW ALOFT WILL MAINTAIN SOUTH-SOUTHEAST WINDS THE KSLC
TERMINAL THROUGH THE NIGHT. AN UPPER LOW MOVING NORTH ACROSS THE
STATE WILL BRING SHOWERS BACK INTO THE TERMINAL AREA AFTER 06Z.
THE BEST CHANCE FOR RAIN WILL EXIST BETWEEN 08Z AND 15Z. VFR
CONDITIONS WILL PREVAIL...THOUGH CEILINGS COULD DIP DOWN TO
AROUND 7000 TO 8000 FEET IN PRECIP.

&&

.FIRE WEATHER...A WEATHER DISTURBANCE IS TRACKING ALONG THE
UTAH/NEVADA BORDER THIS AFTERNOON...ALLOWING DEEP MOISTURE TO
SPREAD INTO THE SOUTHERN TWO-THIRDS OF UTAH. SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED IN THIS MOIST AND
UNSTABLE AIRMASS...AND THE FOCUS OF CONVECTION WILL SHIFT
NORTHWARD THIS EVENING AS THE DISTURBANCE CONTINUES
NORTHWARD...THEN CUTS OVER NORTHERN UTAH TONIGHT AND TOMORROW.
THERE IS A CHANCE OF WETTING RAIN WITH ANY OF THESE SHOWERS AND
THUNDERSTORMS. WITH THE NORTHWARD MOVEMENT OF THE
DISTURBANCE...DRIER AIR WILL MOVE BACK INTO THE DISTRICT FROM THE
SOUTH TONIGHT THROUGH TUESDAY. UNDER THE INFLUENCE OF THE
WAVE...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER
NORTHERN UTAH TOMORROW BEFORE COVERAGE DECREASE TUESDAY UNDER WEAK
HIGH PRESSURE. SOUTHERLY WINDS WILL BEGIN TO INCREASE TUESDAY AND
WEDNESDAY AS ANOTHER TROUGH BEGINS TO APPROACH THE AREA.

&&

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

$$

SHORT TERM/AVIATION...CONGER
LONG TERM...VERZELLA
FIRE WEATHER...TRAPHAGAN

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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