Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 190302
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
902 PM MDT MON MAY 18 2015

.SYNOPSIS...A STORM SYSTEM OVER CALIFORNIA AND SOUTHERN NEVADA
WILL MOVE NORTHEAST INTO NORTHERN PORTIONS OF NEVADA AND UTAH
TONIGHT THROUGH TUESDAY. THE NEXT STORM SYSTEM WILL ARRIVE LATE IN
THE WEEK AND IMPACT MUCH OF UTAH THROUGH AT LEAST THE FIRST HALF
OF THE WEEKEND.



&&

.DISCUSSION...AN ELONGATED AND BROAD MID LEVEL CIRCULATION
ENCOMPASSES MUCH OF NV/CENTRAL CA THIS EVENING...AND IS INDUCING
A BROAD REGION OF UPPER LEVEL DIFFLUENCE DOWNSTREAM ACROSS MUCH OF
UT. THIS SYNOPTIC SCALE LIFT COUPLED WITH AMBLE MOISTURE AND
MODEST INSTABILITY HAS RESULTED IN A COUPLE OF WAVES OF
THUNDERSTORMS ACROSS NORTHERN AND CENTRAL UT...WITH HEAVY ALBEIT
RELATIVELY BRIEF HEAVY RAIN ALONG WITH NUMEROUS REPORTS OF HAIL.
THE STRONGEST STORMS ARE CURRENTLY EXITING THE FORECAST AREA INTO
SOUTHERN ID...WHILE ADDITIONAL SHOWERS HAVE DEVELOPED ACROSS
SOUTHERN AND CENTRAL UT AND ARE WORKING THEIR WAY NORTHWARD. WILL
LIKELY UPDATE LATER ON THIS EVENING TO ADJUST POP/WX WORDING TO
MORE OF A SCATTERED COVERAGE GIVEN LIMITED INSTABILITY AND AN
EXPECTED GRADUAL DECREASE IN SYNOPTIC FORCING.

THIS UPPER CIRCULATION IS FORECAST TO LIFT NORTHEAST OVERNIGHT
INTO EARLY TUESDAY...WITH THE RESIDUAL MID LEVEL TROUGH AXIS
EXPECTED TO EXTEND FROM CENTRAL WY THROUGH SOUTHERN ID AND INTO
FAR NORTHERN NV BY 00Z WEDNESDAY. GIVEN THIS EXPECTED
EVOLUTION...IT APPEARS LARGE SCALE FORCING WILL REMAIN MODEST
ACROSS THE FORECAST AREA DURING THE DAY TUESDAY AND PRECIPITATION
WILL LIKELY BE MORE DRIVEN BY CONVECTION FIRING OF THE HIGHER
TERRAIN.

THE UPPER FLOW IS FORECAST TO BACK WEDNESDAY...AHEAD OF THE NEXT
UPPER LOW WHICH IS FORECAST TO ROTATE INLAND FRIDAY...THEN
EASTWARD ACROSS THE GREAT BASIN FRIDAY NIGHT INTO SATURDAY
RESULTING IN ANOTHER FAVORABLE SETUP FOR WIDESPREAD PRECIPITATION
ACROSS MUCH OF THE FORECAST AREA.

&&

.AVIATION...PERIODIC SHOWERS WITH A SMALL THREAT FOR A
THUNDERSTORM OR TWO CAN BE EXPECTED IN AND AROUND THE KSLC
TERMINAL THROUGH THE OVERNIGHT HOURS. CONDITIONS WILL PRIMARILY
REMAIN IN THE VFR RANGE...ALTHOUGH BRIEF PERIODS WITH MVFR
CIGS/VIS WILL BE POSSIBLE WITH PASSING SHOWERS. NORTHERLY WINDS
ARE EXPECTED TO SWITCH BACK TO THE SOUTH BY 04Z...HOWEVER
OCCASIONAL OUTFLOW FROM PASSING SHOWERS MAY RESULT IN VARIABLE
WIND DIRECTIONS AND SPEEDS AT TIMES.

&&

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

$$

SEAMAN

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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