Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 281023
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
423 AM MDT THU MAY 28 2015

.SYNOPSIS...AN UPPER LOW OVER THE NORTHERN ROCKIES WILL MOVE EAST
INTO THE PLAINS STATES BY FRIDAY. HIGH PRESSURE ALOFT WILL
STRENGTHEN ACROSS THE REGION THIS WEEKEND...RESULTING IN A
SUBSTANTIAL WARMING AND DRYING TREND.

&&

.SHORT TERM (THROUGH 06Z MONDAY)...THE UPPER LOW CURRENTLY
POSITIONED ACROSS SOUTHWEST MONTANA/EASTERN IDAHO WILL BECOME AN
OPEN TROUGH AND WEAKEN AS IT HEADS FOR THE NORTHERN/CENTRAL PLAINS
STATES FRIDAY.

LOOKING AT ANOTHER DAY OF ACTIVE CONVECTION AS AT LEAST DYNAMIC
FEATURES ROTATE EAST THROUGH THE REGION. THE FIRST SYSTEM ROTATING
EAST THROUGH NORTHWEST UTAH AT TIME IS PRODUCING A LINE OF
SHOWERS/STORMS ACROSS THE SALT FLATS. THE LEFT EXIT REGION OF THE
JET STREAK OVER NORTHWEST UTAH COULD SUPPORT THIS CONVECTION AS IT
MOVES INTO THE NORTHERN/CENTRAL URBAN CORRIDOR AROUND SUNRISE.

SUBSIDENCE BEHIND THIS FIRST SHORTWAVE WILL BE SHORT-LIVED AS THE
SECOND SHORTWAVE CURRENTLY MOVING SOUTH ALONG THE WESTERN FLANK
OF THE UPPER LOW WILL TURN EAST ACROSS NORTHERN/CENTRAL UTAH AND
SOUTHWEST WYOMING LATE THIS MORNING THROUGH THIS AFTERNOON. THE
STRUCTURE OF THIS SECOND FEATURE LOOKS GOOD FOR DEEP CONVECTION...
ESPECIALLY DURING THE LATE MORNING AND AFTERNOON HOURS. MID-LEVEL
COOLING ASSOCIATED WITH THE UPPER LOW TO DESTABILIZE THE AIR MASS
ALONG WITH INCREASING DYNAMIC LIFT AND THE STILL PRESENT JET
SUPPORT SHOULD ALLOW CONVECTION TO DEVELOP AGAIN DURING THE LATE
MORNING/EARLY AFTERNOON HOURS. INCREASING 700-400MB SHEAR DURING
THE AFTERNOON COULD SUPPORT STRONG CONVECTION ACROSS MAINLY
CENTRAL UTAH DURING THE MID TO LATE AFTERNOON HOURS.

SHOWERS AND ISOLATED THUNDERSTORMS WILL LINGER TONIGHT...WITH THIS
ACTIVITY CONFINED MAINLY ACROSS NORTHEAST THROUGH SOUTHWEST UTAH.
HIGH PRESSURE ALOFT WILL BEGIN TO BUILD INTO THE WESTERN GREAT
BASIN TONIGHT...THEN EXPAND EAST ACROSS UTAH FOR FRIDAY THROUGH
THE UPCOMING WEEKEND. THIS BUILDING RIDGE WILL START A DRYING AND
WARMING TREND...WITH TEMPERATURES ENDING UP ABOVE NORMAL AREA WIDE
THROUGH THE WEEKEND.

.LONG TERM (AFTER 06Z MONDAY)...PRIMARY FOCUS IN THE LONG TERM
FORECAST CONTINUES TO BE THE MARKED WARMING/DRYING TREND THAT WILL
CONTINUE INTO EARLY NEXT WEEK. GUIDANCE CONTINUES TO TREND H7 TEMPS
SLIGHTLY WARMER SUN-MON WITH VALUES NOW PUSHING +14 C AT KSLC.
ENCROACHMENT OF YET ANOTHER PACIFIC TROUGH INTO THE WESTERN CONUS
WILL STRENGTHEN MID LEVEL SOUTHWESTERLY FLOW...AND NET DRYING AT THE
LOW LEVELS WILL PROMOTE DEEP MIXING OF THIS AIRMASS EACH DAY. MADE
MINIMAL CHANGES TO GRIDS OUTSIDE OF UPPING AFTERNOON HIGHS A DEGREE
OR TWO...PRIMARILY ACROSS THE WESTERN VALLEYS.

AFOREMENTIONED TROUGH WILL PRIMARILY REMAIN TO THE NORTH AND WEST OF
THE AREA EARLY/MID NEXT WEEK...THOUGH EJECTING LOBES WITHIN A
CYCLONIC SOUTHWESTERLY FLOW WILL LIKELY CLIP FAR WESTERN/NORTHERN
UTAH DURING THE PERIOD. RESULTANT LOWERING OF HEIGHTS COMBINED WITH
WEAK CAA FROM THE NORTHWEST WILL ALLOW FOR SOME COOLING AND A RETURN
TO NEAR NORMAL TEMPS IN THE NORTH...THIS AFTER RUNNING SOME 10
DEGREES ABOVE. MAINTAINED SLIGHT CHANCE POPS FOR THE FAR
NORTHERN/WESTERN AREAS...THOUGH ANY CONVECTION WILL LIKELY BE
LIMITED TO THE HIGH BASED AND GUSTY WIND VARIETY WITH MINIMAL PRECIP
EXPECTED.

&&

.FIRE WEATHER...AN UPPER LOW CURRENTLY OVER CENTRAL IDAHO WILL PASS
ACROSS NORTHERN PORTIONS OF THE DISTRICT TODAY. EXPECTING YET
ANOTHER INCREASE OF SHOWERS AND STORMS BEGINNING MID MORNING AND
CONTINUING THROUGH THE AFTERNOON...WITH FOCUSED WETTING RAIN
POTENTIAL ACROSS THE NORTHERN HALF OF THE DISTRICT. PASSAGE OF THIS
LOW TONIGHT THROUGH TOMORROW WILL ALLOW A NET DRYING TREND TO TAKE
FORM FROM WEST TO EAST.

HIGH PRESSURE WILL EXPAND INTO THEN BUILD ACROSS THE DISTRICT THIS
WEEKEND BRINGING A MARKED DRYING/WARMING TREND TO ALL AREAS.
SOUTHERLY WINDS WILL INCREASE BEGINNING SUNDAY AS YET ANOTHER
PACIFIC LOW TRANSITIONS INTO THE PACIFIC NORTHWEST REGION. NOT
EXPECTING MUCH IN THE WAY OF STORM ACTIVITY FROM THIS OUTSIDE OF
ISOLATED HIGH BASED SHOWERS/STORMS OF THE GUSTY VARIETY ACROSS FAR
NORTHERN PORTIONS EACH AFTERNOON/EVE. BOTTOM LINE...SIGNIFICANTLY
LOWER RH AND STRENGTHENING SOUTHERLY WINDS IN THE SUN-TUE TIMEFRAME.

&&

.AVIATION...OPERATIONAL WEATHER CONCERNS FOR THE KSLC TERMINAL WILL
CONTINUE TO FOCUS ON PERIODIC SHOWERS AND A 20 PERCENT CHANCE OF
THUNDERSTORMS THROUGH THIS AFTERNOON. PRIMARY IMPACTS FROM PASSING
SHOWERS/STORMS WILL BE A BRIEF REDUCTION OF CIGS TO AOB 6000FT
AGL...GUSTY ERRATIC WINDS AND LIGHTNING IN THE VICINITY OF THE
AIRFIELD. EXPECTING SHOWERS/STORMS TO BUILD OVER NEIGHBORING TERRAIN
EARLIER THAN NORMAL...WITH CB IN THE VICINITY AS EARLY AS 16Z.

&&


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

$$

SHORT TERM...CONGER
LONG TERM/FIRE WEATHER/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)


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