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000
FXUS65 KSLC 231038
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
438 AM MDT SAT MAY 23 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL SLOWLY CROSS
THE REGION THROUGH SUNDAY. HIGH PRESSURE WILL BRIEFLY DEVELOP
MONDAY...BEFORE THE NEXT SYSTEM IMPACTS THE REGION FOR THE MIDDLE
TO LATTER HALF OF NEXT WEEK.

&&

.SHORT TERM (THROUGH 00Z WEDNESDAY)...EARLY MORNING WATER VAPOR
IMAGERY DEPICTS AN UPPER LOW SPINNING NEAR THE UT/AZ
BORDER...WHILE A FAIRLY WELL DEFINED WAVE ROTATING AROUND THE
NORTHERN PERIPHERY OF THIS LOW IS NOTED MOVING INTO NORTHERN
UT/SOUTHERN ID. AS THE PRIMARY UPPER CIRCULATION SLOWLY SHIFTS
INTO EASTERN UT TODAY...THIS NORTHERN WAVE IS FORECAST TO DROP
SOUTHWARD ACROSS WESTERN UT THROUGHOUT THE DAY FOCUSING THE
GREATER PRECIPITATION THREAT ACROSS WEST CENTRAL AND SOUTHWEST UT
AS THE DAY PROGRESSES. IN THE WAKE OF THIS FEATURE DRIER AIR ALOFT
CURRENTLY EXTENDING ACROSS EASTERN UT IS EXPECTED TO WRAP INTO
NORTHERN UT LATER ON...AND COUPLED WITH LARGE SCALE SUBSIDENCE MAY
LIMIT THE PRECIPITATION COVERAGE THIS AFTERNOON OVER THE NORTHERN
THIRD OF THE FORECAST AREA.

IN THE MEANTIME SHOWERS AND ISOLATED THUNDERSTORMS HAVE EXPANDED
IN COVERAGE ACROSS NORTHERN UT OVER THE PAST COUPLE HOURS...AND
ANTICIPATE THESE TO CONTINUE THROUGH AT LEAST MID MORNING BEFORE
SHIFTING SOUTH IN ASSOCIATION WITH THE AFOREMENTIONED WAVE. HAVE
MAINTAINED LIKELY TO CATEGORICAL POPS THIS MORNING ACROSS THE
NORTH...THEN TRENDED POPS DOWNWARD A BIT ACROSS THE NORTH AND
SHIFTED FOCUS FURTHER SOUTH FOR THE AFTERNOON. POPS MAY BE A BIT
OVERDONE OVER THE NORTHERN THIRD OF THE AREA FOR THE
AFTERNOON...ALTHOUGH WITH DAYTIME HEATING ADDITIONAL CONVECTION
IS CERTAINLY POSSIBLE WITH LINGERING LOW LEVEL MOISTURE.

FOR THE REMAINDER OF THE HOLIDAY WEEKEND A NORTHWESTERLY FLOW
ALOFT IS FORECAST TO PREVAIL IN THE WAKE OF THE DEPARTING UPPER
LOW. RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO FUEL ADDITIONAL
SHOWERS AND THUNDERSTORMS LARGELY FOCUSED ON THE HIGHER
TERRAIN...BUT DRIFTING EASTWARD INTO THE ADJACENT VALLEYS AT
TIMES. THESE STORMS WILL LIKELY BE MORE NUMEROUS SUNDAY AS THE
REGION REMAINS UNDER A CYCLONIC FLOW ALOFT...BEFORE A PROGRESSIVE
SHORTWAVE RIDGE BEGINS TO AMPLIFY ACROSS THE FORECAST AREA ON
MONDAY. THIS RIDGE IS DOWNSTREAM FROM THE NEXT UPSTREAM
TROUGH...WHICH IS FORECAST TO DROP INTO THE PACIFIC NORTHWEST AND
INFLUENCE NORTHERN UT TUESDAY BRINGING ANOTHER INCREASE IN
SHOWERS AND THUNDERSTORMS.

.LONG TERM (AFTER 00Z WEDNESDAY)...GLOBAL MODELS COMING INTO BETTER
AGREEMENT WITH THE TRACK OF THE PACIFIC NORTHWEST LOW FOR THE
MIDWEEK PERIOD. EC/GFS TRACK IT SLOWLY INTO IDAHO AND MONTANA BY
WEDNESDAY BEFORE IT WEAKENS AND SLOWLY CONTINUES EAST FOR THURSDAY
AND FRIDAY. THIS WOULD KEEP A BROAD TROUGH OVER THE FORECAST AREA
THROUGH MUCH OF THE WORK WEEK...THOUGH THE BEST MOISTURE AND
INSTABILITY WILL BE CONFINED TO NORTHERN UTAH...WITH THE EXTENT OF
THIS MOISTURE SHRINKING AS THE WEEK GOES ON. MADE ONLY SMALL CHANGES
TO THE POP GRIDS FOR THIS PART OF THE FORECAST...AS SCATTERED POPS
SLOWLY BECOMING ISOLATED SEEMS TO COVER THE EXPECTED SITUATION WELL.
ALSO CONTINUING TO INDICATE SOME VERY SLOW WARMING OF TEMPERATURES
AS MOISTURE DECREASES.

BY THE UPCOMING WEEKEND...HIGH PRESSURE IS FINALLY EXPECTED TO BUILD
BACK INTO UTAH AND SOUTHWEST WYOMING...THOUGH THIS IS A BIT MORE
AMPLIFIED IN THE EC COMPARED TO THE LATEST GFS. HAVE DROPPED POPS
WELL BELOW CLIMO FOR DAY 7 WITH A CONTINUED WARMING TREND.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY AT THE
SLC TERMINAL. SHOWERS ARE EXPECTED TO KEEP CIGS PRIMARILY NEAR OR
BELOW 6000 FT AGL THROUGH THE MORNING. SOUTHEAST WINDS ARE EXPECTED
TO SHIFT TO THE NORTHWEST BETWEEN 21Z AND 23Z...THOUGH SHOWERS WILL
LIKELY RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS INTO THE
AFTERNOON HOURS.

&&

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

$$

SEAMAN/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)




000
FXUS65 KSLC 231038
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
438 AM MDT SAT MAY 23 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL SLOWLY CROSS
THE REGION THROUGH SUNDAY. HIGH PRESSURE WILL BRIEFLY DEVELOP
MONDAY...BEFORE THE NEXT SYSTEM IMPACTS THE REGION FOR THE MIDDLE
TO LATTER HALF OF NEXT WEEK.

&&

.SHORT TERM (THROUGH 00Z WEDNESDAY)...EARLY MORNING WATER VAPOR
IMAGERY DEPICTS AN UPPER LOW SPINNING NEAR THE UT/AZ
BORDER...WHILE A FAIRLY WELL DEFINED WAVE ROTATING AROUND THE
NORTHERN PERIPHERY OF THIS LOW IS NOTED MOVING INTO NORTHERN
UT/SOUTHERN ID. AS THE PRIMARY UPPER CIRCULATION SLOWLY SHIFTS
INTO EASTERN UT TODAY...THIS NORTHERN WAVE IS FORECAST TO DROP
SOUTHWARD ACROSS WESTERN UT THROUGHOUT THE DAY FOCUSING THE
GREATER PRECIPITATION THREAT ACROSS WEST CENTRAL AND SOUTHWEST UT
AS THE DAY PROGRESSES. IN THE WAKE OF THIS FEATURE DRIER AIR ALOFT
CURRENTLY EXTENDING ACROSS EASTERN UT IS EXPECTED TO WRAP INTO
NORTHERN UT LATER ON...AND COUPLED WITH LARGE SCALE SUBSIDENCE MAY
LIMIT THE PRECIPITATION COVERAGE THIS AFTERNOON OVER THE NORTHERN
THIRD OF THE FORECAST AREA.

IN THE MEANTIME SHOWERS AND ISOLATED THUNDERSTORMS HAVE EXPANDED
IN COVERAGE ACROSS NORTHERN UT OVER THE PAST COUPLE HOURS...AND
ANTICIPATE THESE TO CONTINUE THROUGH AT LEAST MID MORNING BEFORE
SHIFTING SOUTH IN ASSOCIATION WITH THE AFOREMENTIONED WAVE. HAVE
MAINTAINED LIKELY TO CATEGORICAL POPS THIS MORNING ACROSS THE
NORTH...THEN TRENDED POPS DOWNWARD A BIT ACROSS THE NORTH AND
SHIFTED FOCUS FURTHER SOUTH FOR THE AFTERNOON. POPS MAY BE A BIT
OVERDONE OVER THE NORTHERN THIRD OF THE AREA FOR THE
AFTERNOON...ALTHOUGH WITH DAYTIME HEATING ADDITIONAL CONVECTION
IS CERTAINLY POSSIBLE WITH LINGERING LOW LEVEL MOISTURE.

FOR THE REMAINDER OF THE HOLIDAY WEEKEND A NORTHWESTERLY FLOW
ALOFT IS FORECAST TO PREVAIL IN THE WAKE OF THE DEPARTING UPPER
LOW. RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO FUEL ADDITIONAL
SHOWERS AND THUNDERSTORMS LARGELY FOCUSED ON THE HIGHER
TERRAIN...BUT DRIFTING EASTWARD INTO THE ADJACENT VALLEYS AT
TIMES. THESE STORMS WILL LIKELY BE MORE NUMEROUS SUNDAY AS THE
REGION REMAINS UNDER A CYCLONIC FLOW ALOFT...BEFORE A PROGRESSIVE
SHORTWAVE RIDGE BEGINS TO AMPLIFY ACROSS THE FORECAST AREA ON
MONDAY. THIS RIDGE IS DOWNSTREAM FROM THE NEXT UPSTREAM
TROUGH...WHICH IS FORECAST TO DROP INTO THE PACIFIC NORTHWEST AND
INFLUENCE NORTHERN UT TUESDAY BRINGING ANOTHER INCREASE IN
SHOWERS AND THUNDERSTORMS.

.LONG TERM (AFTER 00Z WEDNESDAY)...GLOBAL MODELS COMING INTO BETTER
AGREEMENT WITH THE TRACK OF THE PACIFIC NORTHWEST LOW FOR THE
MIDWEEK PERIOD. EC/GFS TRACK IT SLOWLY INTO IDAHO AND MONTANA BY
WEDNESDAY BEFORE IT WEAKENS AND SLOWLY CONTINUES EAST FOR THURSDAY
AND FRIDAY. THIS WOULD KEEP A BROAD TROUGH OVER THE FORECAST AREA
THROUGH MUCH OF THE WORK WEEK...THOUGH THE BEST MOISTURE AND
INSTABILITY WILL BE CONFINED TO NORTHERN UTAH...WITH THE EXTENT OF
THIS MOISTURE SHRINKING AS THE WEEK GOES ON. MADE ONLY SMALL CHANGES
TO THE POP GRIDS FOR THIS PART OF THE FORECAST...AS SCATTERED POPS
SLOWLY BECOMING ISOLATED SEEMS TO COVER THE EXPECTED SITUATION WELL.
ALSO CONTINUING TO INDICATE SOME VERY SLOW WARMING OF TEMPERATURES
AS MOISTURE DECREASES.

BY THE UPCOMING WEEKEND...HIGH PRESSURE IS FINALLY EXPECTED TO BUILD
BACK INTO UTAH AND SOUTHWEST WYOMING...THOUGH THIS IS A BIT MORE
AMPLIFIED IN THE EC COMPARED TO THE LATEST GFS. HAVE DROPPED POPS
WELL BELOW CLIMO FOR DAY 7 WITH A CONTINUED WARMING TREND.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY AT THE
SLC TERMINAL. SHOWERS ARE EXPECTED TO KEEP CIGS PRIMARILY NEAR OR
BELOW 6000 FT AGL THROUGH THE MORNING. SOUTHEAST WINDS ARE EXPECTED
TO SHIFT TO THE NORTHWEST BETWEEN 21Z AND 23Z...THOUGH SHOWERS WILL
LIKELY RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS INTO THE
AFTERNOON HOURS.

&&

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

$$

SEAMAN/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)





000
FXUS65 KSLC 231038
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
438 AM MDT SAT MAY 23 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL SLOWLY CROSS
THE REGION THROUGH SUNDAY. HIGH PRESSURE WILL BRIEFLY DEVELOP
MONDAY...BEFORE THE NEXT SYSTEM IMPACTS THE REGION FOR THE MIDDLE
TO LATTER HALF OF NEXT WEEK.

&&

.SHORT TERM (THROUGH 00Z WEDNESDAY)...EARLY MORNING WATER VAPOR
IMAGERY DEPICTS AN UPPER LOW SPINNING NEAR THE UT/AZ
BORDER...WHILE A FAIRLY WELL DEFINED WAVE ROTATING AROUND THE
NORTHERN PERIPHERY OF THIS LOW IS NOTED MOVING INTO NORTHERN
UT/SOUTHERN ID. AS THE PRIMARY UPPER CIRCULATION SLOWLY SHIFTS
INTO EASTERN UT TODAY...THIS NORTHERN WAVE IS FORECAST TO DROP
SOUTHWARD ACROSS WESTERN UT THROUGHOUT THE DAY FOCUSING THE
GREATER PRECIPITATION THREAT ACROSS WEST CENTRAL AND SOUTHWEST UT
AS THE DAY PROGRESSES. IN THE WAKE OF THIS FEATURE DRIER AIR ALOFT
CURRENTLY EXTENDING ACROSS EASTERN UT IS EXPECTED TO WRAP INTO
NORTHERN UT LATER ON...AND COUPLED WITH LARGE SCALE SUBSIDENCE MAY
LIMIT THE PRECIPITATION COVERAGE THIS AFTERNOON OVER THE NORTHERN
THIRD OF THE FORECAST AREA.

IN THE MEANTIME SHOWERS AND ISOLATED THUNDERSTORMS HAVE EXPANDED
IN COVERAGE ACROSS NORTHERN UT OVER THE PAST COUPLE HOURS...AND
ANTICIPATE THESE TO CONTINUE THROUGH AT LEAST MID MORNING BEFORE
SHIFTING SOUTH IN ASSOCIATION WITH THE AFOREMENTIONED WAVE. HAVE
MAINTAINED LIKELY TO CATEGORICAL POPS THIS MORNING ACROSS THE
NORTH...THEN TRENDED POPS DOWNWARD A BIT ACROSS THE NORTH AND
SHIFTED FOCUS FURTHER SOUTH FOR THE AFTERNOON. POPS MAY BE A BIT
OVERDONE OVER THE NORTHERN THIRD OF THE AREA FOR THE
AFTERNOON...ALTHOUGH WITH DAYTIME HEATING ADDITIONAL CONVECTION
IS CERTAINLY POSSIBLE WITH LINGERING LOW LEVEL MOISTURE.

FOR THE REMAINDER OF THE HOLIDAY WEEKEND A NORTHWESTERLY FLOW
ALOFT IS FORECAST TO PREVAIL IN THE WAKE OF THE DEPARTING UPPER
LOW. RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO FUEL ADDITIONAL
SHOWERS AND THUNDERSTORMS LARGELY FOCUSED ON THE HIGHER
TERRAIN...BUT DRIFTING EASTWARD INTO THE ADJACENT VALLEYS AT
TIMES. THESE STORMS WILL LIKELY BE MORE NUMEROUS SUNDAY AS THE
REGION REMAINS UNDER A CYCLONIC FLOW ALOFT...BEFORE A PROGRESSIVE
SHORTWAVE RIDGE BEGINS TO AMPLIFY ACROSS THE FORECAST AREA ON
MONDAY. THIS RIDGE IS DOWNSTREAM FROM THE NEXT UPSTREAM
TROUGH...WHICH IS FORECAST TO DROP INTO THE PACIFIC NORTHWEST AND
INFLUENCE NORTHERN UT TUESDAY BRINGING ANOTHER INCREASE IN
SHOWERS AND THUNDERSTORMS.

.LONG TERM (AFTER 00Z WEDNESDAY)...GLOBAL MODELS COMING INTO BETTER
AGREEMENT WITH THE TRACK OF THE PACIFIC NORTHWEST LOW FOR THE
MIDWEEK PERIOD. EC/GFS TRACK IT SLOWLY INTO IDAHO AND MONTANA BY
WEDNESDAY BEFORE IT WEAKENS AND SLOWLY CONTINUES EAST FOR THURSDAY
AND FRIDAY. THIS WOULD KEEP A BROAD TROUGH OVER THE FORECAST AREA
THROUGH MUCH OF THE WORK WEEK...THOUGH THE BEST MOISTURE AND
INSTABILITY WILL BE CONFINED TO NORTHERN UTAH...WITH THE EXTENT OF
THIS MOISTURE SHRINKING AS THE WEEK GOES ON. MADE ONLY SMALL CHANGES
TO THE POP GRIDS FOR THIS PART OF THE FORECAST...AS SCATTERED POPS
SLOWLY BECOMING ISOLATED SEEMS TO COVER THE EXPECTED SITUATION WELL.
ALSO CONTINUING TO INDICATE SOME VERY SLOW WARMING OF TEMPERATURES
AS MOISTURE DECREASES.

BY THE UPCOMING WEEKEND...HIGH PRESSURE IS FINALLY EXPECTED TO BUILD
BACK INTO UTAH AND SOUTHWEST WYOMING...THOUGH THIS IS A BIT MORE
AMPLIFIED IN THE EC COMPARED TO THE LATEST GFS. HAVE DROPPED POPS
WELL BELOW CLIMO FOR DAY 7 WITH A CONTINUED WARMING TREND.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY AT THE
SLC TERMINAL. SHOWERS ARE EXPECTED TO KEEP CIGS PRIMARILY NEAR OR
BELOW 6000 FT AGL THROUGH THE MORNING. SOUTHEAST WINDS ARE EXPECTED
TO SHIFT TO THE NORTHWEST BETWEEN 21Z AND 23Z...THOUGH SHOWERS WILL
LIKELY RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS INTO THE
AFTERNOON HOURS.

&&

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

$$

SEAMAN/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)





000
FXUS65 KSLC 231038
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
438 AM MDT SAT MAY 23 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL SLOWLY CROSS
THE REGION THROUGH SUNDAY. HIGH PRESSURE WILL BRIEFLY DEVELOP
MONDAY...BEFORE THE NEXT SYSTEM IMPACTS THE REGION FOR THE MIDDLE
TO LATTER HALF OF NEXT WEEK.

&&

.SHORT TERM (THROUGH 00Z WEDNESDAY)...EARLY MORNING WATER VAPOR
IMAGERY DEPICTS AN UPPER LOW SPINNING NEAR THE UT/AZ
BORDER...WHILE A FAIRLY WELL DEFINED WAVE ROTATING AROUND THE
NORTHERN PERIPHERY OF THIS LOW IS NOTED MOVING INTO NORTHERN
UT/SOUTHERN ID. AS THE PRIMARY UPPER CIRCULATION SLOWLY SHIFTS
INTO EASTERN UT TODAY...THIS NORTHERN WAVE IS FORECAST TO DROP
SOUTHWARD ACROSS WESTERN UT THROUGHOUT THE DAY FOCUSING THE
GREATER PRECIPITATION THREAT ACROSS WEST CENTRAL AND SOUTHWEST UT
AS THE DAY PROGRESSES. IN THE WAKE OF THIS FEATURE DRIER AIR ALOFT
CURRENTLY EXTENDING ACROSS EASTERN UT IS EXPECTED TO WRAP INTO
NORTHERN UT LATER ON...AND COUPLED WITH LARGE SCALE SUBSIDENCE MAY
LIMIT THE PRECIPITATION COVERAGE THIS AFTERNOON OVER THE NORTHERN
THIRD OF THE FORECAST AREA.

IN THE MEANTIME SHOWERS AND ISOLATED THUNDERSTORMS HAVE EXPANDED
IN COVERAGE ACROSS NORTHERN UT OVER THE PAST COUPLE HOURS...AND
ANTICIPATE THESE TO CONTINUE THROUGH AT LEAST MID MORNING BEFORE
SHIFTING SOUTH IN ASSOCIATION WITH THE AFOREMENTIONED WAVE. HAVE
MAINTAINED LIKELY TO CATEGORICAL POPS THIS MORNING ACROSS THE
NORTH...THEN TRENDED POPS DOWNWARD A BIT ACROSS THE NORTH AND
SHIFTED FOCUS FURTHER SOUTH FOR THE AFTERNOON. POPS MAY BE A BIT
OVERDONE OVER THE NORTHERN THIRD OF THE AREA FOR THE
AFTERNOON...ALTHOUGH WITH DAYTIME HEATING ADDITIONAL CONVECTION
IS CERTAINLY POSSIBLE WITH LINGERING LOW LEVEL MOISTURE.

FOR THE REMAINDER OF THE HOLIDAY WEEKEND A NORTHWESTERLY FLOW
ALOFT IS FORECAST TO PREVAIL IN THE WAKE OF THE DEPARTING UPPER
LOW. RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO FUEL ADDITIONAL
SHOWERS AND THUNDERSTORMS LARGELY FOCUSED ON THE HIGHER
TERRAIN...BUT DRIFTING EASTWARD INTO THE ADJACENT VALLEYS AT
TIMES. THESE STORMS WILL LIKELY BE MORE NUMEROUS SUNDAY AS THE
REGION REMAINS UNDER A CYCLONIC FLOW ALOFT...BEFORE A PROGRESSIVE
SHORTWAVE RIDGE BEGINS TO AMPLIFY ACROSS THE FORECAST AREA ON
MONDAY. THIS RIDGE IS DOWNSTREAM FROM THE NEXT UPSTREAM
TROUGH...WHICH IS FORECAST TO DROP INTO THE PACIFIC NORTHWEST AND
INFLUENCE NORTHERN UT TUESDAY BRINGING ANOTHER INCREASE IN
SHOWERS AND THUNDERSTORMS.

.LONG TERM (AFTER 00Z WEDNESDAY)...GLOBAL MODELS COMING INTO BETTER
AGREEMENT WITH THE TRACK OF THE PACIFIC NORTHWEST LOW FOR THE
MIDWEEK PERIOD. EC/GFS TRACK IT SLOWLY INTO IDAHO AND MONTANA BY
WEDNESDAY BEFORE IT WEAKENS AND SLOWLY CONTINUES EAST FOR THURSDAY
AND FRIDAY. THIS WOULD KEEP A BROAD TROUGH OVER THE FORECAST AREA
THROUGH MUCH OF THE WORK WEEK...THOUGH THE BEST MOISTURE AND
INSTABILITY WILL BE CONFINED TO NORTHERN UTAH...WITH THE EXTENT OF
THIS MOISTURE SHRINKING AS THE WEEK GOES ON. MADE ONLY SMALL CHANGES
TO THE POP GRIDS FOR THIS PART OF THE FORECAST...AS SCATTERED POPS
SLOWLY BECOMING ISOLATED SEEMS TO COVER THE EXPECTED SITUATION WELL.
ALSO CONTINUING TO INDICATE SOME VERY SLOW WARMING OF TEMPERATURES
AS MOISTURE DECREASES.

BY THE UPCOMING WEEKEND...HIGH PRESSURE IS FINALLY EXPECTED TO BUILD
BACK INTO UTAH AND SOUTHWEST WYOMING...THOUGH THIS IS A BIT MORE
AMPLIFIED IN THE EC COMPARED TO THE LATEST GFS. HAVE DROPPED POPS
WELL BELOW CLIMO FOR DAY 7 WITH A CONTINUED WARMING TREND.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY AT THE
SLC TERMINAL. SHOWERS ARE EXPECTED TO KEEP CIGS PRIMARILY NEAR OR
BELOW 6000 FT AGL THROUGH THE MORNING. SOUTHEAST WINDS ARE EXPECTED
TO SHIFT TO THE NORTHWEST BETWEEN 21Z AND 23Z...THOUGH SHOWERS WILL
LIKELY RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS INTO THE
AFTERNOON HOURS.

&&

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

$$

SEAMAN/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)




000
FXUS65 KSLC 230402
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1002 PM MDT FRI MAY 22 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST
ACROSS THE SOUTHERN AND EASTERN GREAT BASIN THIS WEEKEND.

&&

.DISCUSSION...A CLOSED LOW CENTERED OVER NORTHWEST ARIZONA IS STILL
ON TRACK TO CROSS SOUTH-CENTRAL THROUGH EAST-CENTRAL UTAH TONIGHT
AND TOMORROW. THE STRONGEST THUNDERSTORMS TODAY DEVELOPED ACROSS
NORTHERN UTAH...WHERE SCATTERED SHOWERS STILL LINGER BUT WITH MUCH
LESS INTENSITY. THIS SHOULD REMAIN THE TREND THROUGH MUCH OF THE
NIGHT. SHOWERS ACROSS SOUTHWESTERN AND PORTIONS OF CENTRAL UTAH
SHOULD TREND MORE DEVELOPMENTAL THROUGH THE NIGHT OWING TO LARGE-
SCALE LIFT TO THE NORTH AND WEST OF THE LOW.

STILL LOOKING AT WIDESPREAD PRECIPITATION FOR PARTS OF NORTHERN AND
WESTERN UTAH TOMORROW. HOWEVER...LATEST MODELS HAVE TRENDED TOWARDS
A SLOWER DEVELOPMENT OF PRECIPITATION...AFTER 12Z...AS WARM
ADVECTION ALOFT IS PROGGED TO TAKE LONGER TO STRENGTHEN.
NEVERTHELESS...ONCE IT GETS GOING EXPECT A PERIOD OF MODERATE
PRECIPITATION ACROSS SAID AREAS...AND WRAPPING BACK INTO SOUTHWEST
UTAH. PRECIPITATION IS THEN EXPECTED TO TAPER OFF NORTH TO SOUTH
BEGINNING LATE TOMORROW AFTERNOON THROUGH TOMORROW NIGHT AS A MORE
STABLE AIRMASS DEVELOPS IN THE WAKE OF AN EMBEDDED SHORTWAVE
ROTATING AROUND THE LOW.

UPDATED THE FORECAST MAINLY TO ADJUST POP/SKY FOR THE REMAINDER OF
THE NIGHT.

&&

.AVIATION...SOUTH WINDS ARE EXPECTED TO PREVAIL AT THE SLC TERMINAL
THROUGH THE NIGHT. THERE IS A 20 PERCENT CHANCE OF CIGS LOWERING
BELOW 7000FT BETWEEN 09-12Z...40 PERCENT AFTER 12Z AS SHOWERS BEGIN
TO DEVELOP IN THE VICINITY OF THE TERMINAL.

&&

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

$$

CHENG

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)





000
FXUS65 KSLC 230402
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1002 PM MDT FRI MAY 22 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST
ACROSS THE SOUTHERN AND EASTERN GREAT BASIN THIS WEEKEND.

&&

.DISCUSSION...A CLOSED LOW CENTERED OVER NORTHWEST ARIZONA IS STILL
ON TRACK TO CROSS SOUTH-CENTRAL THROUGH EAST-CENTRAL UTAH TONIGHT
AND TOMORROW. THE STRONGEST THUNDERSTORMS TODAY DEVELOPED ACROSS
NORTHERN UTAH...WHERE SCATTERED SHOWERS STILL LINGER BUT WITH MUCH
LESS INTENSITY. THIS SHOULD REMAIN THE TREND THROUGH MUCH OF THE
NIGHT. SHOWERS ACROSS SOUTHWESTERN AND PORTIONS OF CENTRAL UTAH
SHOULD TREND MORE DEVELOPMENTAL THROUGH THE NIGHT OWING TO LARGE-
SCALE LIFT TO THE NORTH AND WEST OF THE LOW.

STILL LOOKING AT WIDESPREAD PRECIPITATION FOR PARTS OF NORTHERN AND
WESTERN UTAH TOMORROW. HOWEVER...LATEST MODELS HAVE TRENDED TOWARDS
A SLOWER DEVELOPMENT OF PRECIPITATION...AFTER 12Z...AS WARM
ADVECTION ALOFT IS PROGGED TO TAKE LONGER TO STRENGTHEN.
NEVERTHELESS...ONCE IT GETS GOING EXPECT A PERIOD OF MODERATE
PRECIPITATION ACROSS SAID AREAS...AND WRAPPING BACK INTO SOUTHWEST
UTAH. PRECIPITATION IS THEN EXPECTED TO TAPER OFF NORTH TO SOUTH
BEGINNING LATE TOMORROW AFTERNOON THROUGH TOMORROW NIGHT AS A MORE
STABLE AIRMASS DEVELOPS IN THE WAKE OF AN EMBEDDED SHORTWAVE
ROTATING AROUND THE LOW.

UPDATED THE FORECAST MAINLY TO ADJUST POP/SKY FOR THE REMAINDER OF
THE NIGHT.

&&

.AVIATION...SOUTH WINDS ARE EXPECTED TO PREVAIL AT THE SLC TERMINAL
THROUGH THE NIGHT. THERE IS A 20 PERCENT CHANCE OF CIGS LOWERING
BELOW 7000FT BETWEEN 09-12Z...40 PERCENT AFTER 12Z AS SHOWERS BEGIN
TO DEVELOP IN THE VICINITY OF THE TERMINAL.

&&

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

$$

CHENG

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)




000
FXUS65 KSLC 222341
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
541 PM MDT FRI MAY 22 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST
ACROSS THE SOUTHERN AND EASTERN GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z TUESDAY)...THE UPPER LOW CURRENTLY OVER
NORTHWEST ARIZONA WILL CONTINUE ON A SLOW STEADY NORTHEAST TRACK
THROUGH SOUTHERN AND EASTERN LATER TONIGHT THROUGH THE DAY
SATURDAY. SCATTERED CONVECTION THAT FIRED UP LATE THIS MORNING
OVER CENTRAL UTAH CONTINUED SLOWLY NORTH INTO NORTHERN UTAH DURING
THE AFTERNOON. WEAK MEAN LAYER FLOW ALLOWED THESE SLOW-MOVING
SHOWERS/STORMS TO PUT DOWN BRIEF HEAVY RAIN AND SMALL HAIL THIS
AFTERNOON. THE CONVECTION HAS BEEN WEAKENING THE PAST HOUR OR SO
AS IT MOVES INTO MARGINALLY MORE STABLE AIR AND LESS DYNAMIC
FORCING.

SOUTHERN UTAH WILL SEE AN INCREASE IN CONVECTION THIS EVENING AS
THE UPPER LOW MOVES NORTHEAST INTO THE STATE. SOLID SYNOPTIC-
SCALE AND A FAVORABLE MOISTURE WILL PRODUCE POCKETS OF HEAVY
PRECIP OVERNIGHT ALONG THE NORTH AND WEST FLANKS OF THE LOW.

PRECIP WILL SHIFT INTO NORTHERN AND FAR WESTERN UTAH EARLY
SATURDAY. THE HEAVIEST PRECIP WILL REMAIN IN CLOSE PROXIMITY TO
THE UPPER LOW OVER NORTHEAST UTAH...WITH A SECONDARY AREA ACROSS
NORTHWEST UTAH IN ASSOCIATION WITH WARM ADVECTION GENERATED LIFT.
THIS THERMALLY DRIVEN LIFT WILL SLIDE SOUTH ALONG THE UTAH/NEVADA
BORDER DURING THE DAY...THEN FOCUS ON SOUTHWEST UTAH LATE
SATURDAY THROUGH EARLY SUNDAY. LOOKING AT ANOTHER ROUND OF
SIGNIFICANT PRECIP FOR THE SOUTH...ESPECIALLY DURING THE OVERNIGHT
HOURS SATURDAY.

RESIDUAL MOISTURE AND A COUPLE OF WEAK TRAILING SHORTWAVES BEHIND
THE EXITING UPPER LOW SHOULD PRODUCE ADDITIONAL SCATTERED
CONVECTION ACROSS NORTHERN AND WESTERN UTAH ON SUNDAY
AFTERNOON/EVENING. A TRAILING SHORTWAVE RIDGE WILL REACH UTAH ON
MONDAY...LIMITING THE AREAL COVERAGE OF ANY CONVECTION AND
CONFINING THIS TO MAINLY THE HIGHER TERRAIN THROUGH EARLY MONDAY
EVENING.

.LONG TERM (AFTER 06Z TUESDAY)...FEATURES TO FOCUS ON THROUGH THE
LONG TERM PERIOD ARE THE TRACK OF A REMNANT LOW AS IN MEANDERS
SOUTH AND EAST FROM BRITCOL INTO THE PACNW/NORTHERN ROCKIES...AND
WEAK SHORT WAVES TRANSLATING THROUGH THE DESERT SOUTHWEST
ASSOCIATED WITH THE SOUTHERN BRANCH JET. IN GENERAL THE
COMBINATION OF BOTH WILL MAINTAIN A GENERAL TROUGH OVER THE
EASTERN GREAT BASIN THROUGH THURSDAY...THIS ALLOWING UNSETTLED
CONDITIONS TO CONTINUE THROUGH LATE WEEK /ESPECIALLY ACROSS
NORTHERN AND CENTRAL PORTIONS/.

A COMBINATION OF CONDITIONAL INSTABILITY...MAINTENANCE OF DEEP LAYER
MOISTURE AND WEAK LARGE SCALE FORCING IS EXPECTED TO MAINTAIN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FOCUSED OVER THE
NORTHERN 2/3RDS OF THE AREA EACH DAY THROUGH WEDNESDAY. EXPECTING
COVERAGE OF THESE TO BE GREATEST ACROSS THE NORTH DUE TO CLOSER
PROXIMITY TO THE WEAK UPPER LOW TRANSLATING FROM THE PACNW INTO THE
NORTHERN ROCKIES. NOCTURNAL SHOWERS WILL REMAIN POSSIBLE DUE TO WEAK
FORCING AIDED BY PASSAGE OF WAVES ASSOCIATED WITHIN THE SOUTHERN
BRANCH.

GFS/ECMWF CONTINUE TO SLIGHTLY DIFFER IN DOWNSTREAM EVOLUTION OF THE
LOW TO THE NORTH...BUT DO BOTH SUGGEST THE MEAN TROUGH AXIS WILL
SWEEP EAST OF THE FORECAST AREA THURSDAY ALLOWING BUILDING STABILITY
AND NET DRYING FROM THE WEST. A MORE NOTED WARMING TREND LOOKS
LIKELY LATE WEEK DUE TO THIS AND ADJUSTED TEMPS UP A BIT TO ACCOUNT
FOR THIS.

&&

.AVIATION...ANTICIPATING THAT PERIODS OF ERRATIC WINDS DUE TO
PASSING SHOWERS WILL BE THE PRIMARY OPERATIONAL WEATHER CONCERN AT
THE KSLC TERMINAL THROUGH THIS EVENING. PREVAILING WINDS ARE
EXPECTED TO REMAIN GENERALLY LIGHT FROM THE WEST/NORTHWEST THROUGH
01/02Z...BUT OUTFLOWS FROM SHOWERS APPROACHING FROM THE SOUTHEAST
WILL LIKELY ALLOW SOUTHERLY WINDS TO RETURN EARLIER THAN NORMAL
AROUND 01/02Z.

&&

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

$$

SHORT TERM...CONGER
LONG TERM/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)





000
FXUS65 KSLC 222341
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
541 PM MDT FRI MAY 22 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST
ACROSS THE SOUTHERN AND EASTERN GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z TUESDAY)...THE UPPER LOW CURRENTLY OVER
NORTHWEST ARIZONA WILL CONTINUE ON A SLOW STEADY NORTHEAST TRACK
THROUGH SOUTHERN AND EASTERN LATER TONIGHT THROUGH THE DAY
SATURDAY. SCATTERED CONVECTION THAT FIRED UP LATE THIS MORNING
OVER CENTRAL UTAH CONTINUED SLOWLY NORTH INTO NORTHERN UTAH DURING
THE AFTERNOON. WEAK MEAN LAYER FLOW ALLOWED THESE SLOW-MOVING
SHOWERS/STORMS TO PUT DOWN BRIEF HEAVY RAIN AND SMALL HAIL THIS
AFTERNOON. THE CONVECTION HAS BEEN WEAKENING THE PAST HOUR OR SO
AS IT MOVES INTO MARGINALLY MORE STABLE AIR AND LESS DYNAMIC
FORCING.

SOUTHERN UTAH WILL SEE AN INCREASE IN CONVECTION THIS EVENING AS
THE UPPER LOW MOVES NORTHEAST INTO THE STATE. SOLID SYNOPTIC-
SCALE AND A FAVORABLE MOISTURE WILL PRODUCE POCKETS OF HEAVY
PRECIP OVERNIGHT ALONG THE NORTH AND WEST FLANKS OF THE LOW.

PRECIP WILL SHIFT INTO NORTHERN AND FAR WESTERN UTAH EARLY
SATURDAY. THE HEAVIEST PRECIP WILL REMAIN IN CLOSE PROXIMITY TO
THE UPPER LOW OVER NORTHEAST UTAH...WITH A SECONDARY AREA ACROSS
NORTHWEST UTAH IN ASSOCIATION WITH WARM ADVECTION GENERATED LIFT.
THIS THERMALLY DRIVEN LIFT WILL SLIDE SOUTH ALONG THE UTAH/NEVADA
BORDER DURING THE DAY...THEN FOCUS ON SOUTHWEST UTAH LATE
SATURDAY THROUGH EARLY SUNDAY. LOOKING AT ANOTHER ROUND OF
SIGNIFICANT PRECIP FOR THE SOUTH...ESPECIALLY DURING THE OVERNIGHT
HOURS SATURDAY.

RESIDUAL MOISTURE AND A COUPLE OF WEAK TRAILING SHORTWAVES BEHIND
THE EXITING UPPER LOW SHOULD PRODUCE ADDITIONAL SCATTERED
CONVECTION ACROSS NORTHERN AND WESTERN UTAH ON SUNDAY
AFTERNOON/EVENING. A TRAILING SHORTWAVE RIDGE WILL REACH UTAH ON
MONDAY...LIMITING THE AREAL COVERAGE OF ANY CONVECTION AND
CONFINING THIS TO MAINLY THE HIGHER TERRAIN THROUGH EARLY MONDAY
EVENING.

.LONG TERM (AFTER 06Z TUESDAY)...FEATURES TO FOCUS ON THROUGH THE
LONG TERM PERIOD ARE THE TRACK OF A REMNANT LOW AS IN MEANDERS
SOUTH AND EAST FROM BRITCOL INTO THE PACNW/NORTHERN ROCKIES...AND
WEAK SHORT WAVES TRANSLATING THROUGH THE DESERT SOUTHWEST
ASSOCIATED WITH THE SOUTHERN BRANCH JET. IN GENERAL THE
COMBINATION OF BOTH WILL MAINTAIN A GENERAL TROUGH OVER THE
EASTERN GREAT BASIN THROUGH THURSDAY...THIS ALLOWING UNSETTLED
CONDITIONS TO CONTINUE THROUGH LATE WEEK /ESPECIALLY ACROSS
NORTHERN AND CENTRAL PORTIONS/.

A COMBINATION OF CONDITIONAL INSTABILITY...MAINTENANCE OF DEEP LAYER
MOISTURE AND WEAK LARGE SCALE FORCING IS EXPECTED TO MAINTAIN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FOCUSED OVER THE
NORTHERN 2/3RDS OF THE AREA EACH DAY THROUGH WEDNESDAY. EXPECTING
COVERAGE OF THESE TO BE GREATEST ACROSS THE NORTH DUE TO CLOSER
PROXIMITY TO THE WEAK UPPER LOW TRANSLATING FROM THE PACNW INTO THE
NORTHERN ROCKIES. NOCTURNAL SHOWERS WILL REMAIN POSSIBLE DUE TO WEAK
FORCING AIDED BY PASSAGE OF WAVES ASSOCIATED WITHIN THE SOUTHERN
BRANCH.

GFS/ECMWF CONTINUE TO SLIGHTLY DIFFER IN DOWNSTREAM EVOLUTION OF THE
LOW TO THE NORTH...BUT DO BOTH SUGGEST THE MEAN TROUGH AXIS WILL
SWEEP EAST OF THE FORECAST AREA THURSDAY ALLOWING BUILDING STABILITY
AND NET DRYING FROM THE WEST. A MORE NOTED WARMING TREND LOOKS
LIKELY LATE WEEK DUE TO THIS AND ADJUSTED TEMPS UP A BIT TO ACCOUNT
FOR THIS.

&&

.AVIATION...ANTICIPATING THAT PERIODS OF ERRATIC WINDS DUE TO
PASSING SHOWERS WILL BE THE PRIMARY OPERATIONAL WEATHER CONCERN AT
THE KSLC TERMINAL THROUGH THIS EVENING. PREVAILING WINDS ARE
EXPECTED TO REMAIN GENERALLY LIGHT FROM THE WEST/NORTHWEST THROUGH
01/02Z...BUT OUTFLOWS FROM SHOWERS APPROACHING FROM THE SOUTHEAST
WILL LIKELY ALLOW SOUTHERLY WINDS TO RETURN EARLIER THAN NORMAL
AROUND 01/02Z.

&&

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

$$

SHORT TERM...CONGER
LONG TERM/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)




000
FXUS65 KSLC 222341
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
541 PM MDT FRI MAY 22 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST
ACROSS THE SOUTHERN AND EASTERN GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z TUESDAY)...THE UPPER LOW CURRENTLY OVER
NORTHWEST ARIZONA WILL CONTINUE ON A SLOW STEADY NORTHEAST TRACK
THROUGH SOUTHERN AND EASTERN LATER TONIGHT THROUGH THE DAY
SATURDAY. SCATTERED CONVECTION THAT FIRED UP LATE THIS MORNING
OVER CENTRAL UTAH CONTINUED SLOWLY NORTH INTO NORTHERN UTAH DURING
THE AFTERNOON. WEAK MEAN LAYER FLOW ALLOWED THESE SLOW-MOVING
SHOWERS/STORMS TO PUT DOWN BRIEF HEAVY RAIN AND SMALL HAIL THIS
AFTERNOON. THE CONVECTION HAS BEEN WEAKENING THE PAST HOUR OR SO
AS IT MOVES INTO MARGINALLY MORE STABLE AIR AND LESS DYNAMIC
FORCING.

SOUTHERN UTAH WILL SEE AN INCREASE IN CONVECTION THIS EVENING AS
THE UPPER LOW MOVES NORTHEAST INTO THE STATE. SOLID SYNOPTIC-
SCALE AND A FAVORABLE MOISTURE WILL PRODUCE POCKETS OF HEAVY
PRECIP OVERNIGHT ALONG THE NORTH AND WEST FLANKS OF THE LOW.

PRECIP WILL SHIFT INTO NORTHERN AND FAR WESTERN UTAH EARLY
SATURDAY. THE HEAVIEST PRECIP WILL REMAIN IN CLOSE PROXIMITY TO
THE UPPER LOW OVER NORTHEAST UTAH...WITH A SECONDARY AREA ACROSS
NORTHWEST UTAH IN ASSOCIATION WITH WARM ADVECTION GENERATED LIFT.
THIS THERMALLY DRIVEN LIFT WILL SLIDE SOUTH ALONG THE UTAH/NEVADA
BORDER DURING THE DAY...THEN FOCUS ON SOUTHWEST UTAH LATE
SATURDAY THROUGH EARLY SUNDAY. LOOKING AT ANOTHER ROUND OF
SIGNIFICANT PRECIP FOR THE SOUTH...ESPECIALLY DURING THE OVERNIGHT
HOURS SATURDAY.

RESIDUAL MOISTURE AND A COUPLE OF WEAK TRAILING SHORTWAVES BEHIND
THE EXITING UPPER LOW SHOULD PRODUCE ADDITIONAL SCATTERED
CONVECTION ACROSS NORTHERN AND WESTERN UTAH ON SUNDAY
AFTERNOON/EVENING. A TRAILING SHORTWAVE RIDGE WILL REACH UTAH ON
MONDAY...LIMITING THE AREAL COVERAGE OF ANY CONVECTION AND
CONFINING THIS TO MAINLY THE HIGHER TERRAIN THROUGH EARLY MONDAY
EVENING.

.LONG TERM (AFTER 06Z TUESDAY)...FEATURES TO FOCUS ON THROUGH THE
LONG TERM PERIOD ARE THE TRACK OF A REMNANT LOW AS IN MEANDERS
SOUTH AND EAST FROM BRITCOL INTO THE PACNW/NORTHERN ROCKIES...AND
WEAK SHORT WAVES TRANSLATING THROUGH THE DESERT SOUTHWEST
ASSOCIATED WITH THE SOUTHERN BRANCH JET. IN GENERAL THE
COMBINATION OF BOTH WILL MAINTAIN A GENERAL TROUGH OVER THE
EASTERN GREAT BASIN THROUGH THURSDAY...THIS ALLOWING UNSETTLED
CONDITIONS TO CONTINUE THROUGH LATE WEEK /ESPECIALLY ACROSS
NORTHERN AND CENTRAL PORTIONS/.

A COMBINATION OF CONDITIONAL INSTABILITY...MAINTENANCE OF DEEP LAYER
MOISTURE AND WEAK LARGE SCALE FORCING IS EXPECTED TO MAINTAIN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FOCUSED OVER THE
NORTHERN 2/3RDS OF THE AREA EACH DAY THROUGH WEDNESDAY. EXPECTING
COVERAGE OF THESE TO BE GREATEST ACROSS THE NORTH DUE TO CLOSER
PROXIMITY TO THE WEAK UPPER LOW TRANSLATING FROM THE PACNW INTO THE
NORTHERN ROCKIES. NOCTURNAL SHOWERS WILL REMAIN POSSIBLE DUE TO WEAK
FORCING AIDED BY PASSAGE OF WAVES ASSOCIATED WITHIN THE SOUTHERN
BRANCH.

GFS/ECMWF CONTINUE TO SLIGHTLY DIFFER IN DOWNSTREAM EVOLUTION OF THE
LOW TO THE NORTH...BUT DO BOTH SUGGEST THE MEAN TROUGH AXIS WILL
SWEEP EAST OF THE FORECAST AREA THURSDAY ALLOWING BUILDING STABILITY
AND NET DRYING FROM THE WEST. A MORE NOTED WARMING TREND LOOKS
LIKELY LATE WEEK DUE TO THIS AND ADJUSTED TEMPS UP A BIT TO ACCOUNT
FOR THIS.

&&

.AVIATION...ANTICIPATING THAT PERIODS OF ERRATIC WINDS DUE TO
PASSING SHOWERS WILL BE THE PRIMARY OPERATIONAL WEATHER CONCERN AT
THE KSLC TERMINAL THROUGH THIS EVENING. PREVAILING WINDS ARE
EXPECTED TO REMAIN GENERALLY LIGHT FROM THE WEST/NORTHWEST THROUGH
01/02Z...BUT OUTFLOWS FROM SHOWERS APPROACHING FROM THE SOUTHEAST
WILL LIKELY ALLOW SOUTHERLY WINDS TO RETURN EARLIER THAN NORMAL
AROUND 01/02Z.

&&

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

$$

SHORT TERM...CONGER
LONG TERM/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)




000
FXUS65 KSLC 222341
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
541 PM MDT FRI MAY 22 2015

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST
ACROSS THE SOUTHERN AND EASTERN GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z TUESDAY)...THE UPPER LOW CURRENTLY OVER
NORTHWEST ARIZONA WILL CONTINUE ON A SLOW STEADY NORTHEAST TRACK
THROUGH SOUTHERN AND EASTERN LATER TONIGHT THROUGH THE DAY
SATURDAY. SCATTERED CONVECTION THAT FIRED UP LATE THIS MORNING
OVER CENTRAL UTAH CONTINUED SLOWLY NORTH INTO NORTHERN UTAH DURING
THE AFTERNOON. WEAK MEAN LAYER FLOW ALLOWED THESE SLOW-MOVING
SHOWERS/STORMS TO PUT DOWN BRIEF HEAVY RAIN AND SMALL HAIL THIS
AFTERNOON. THE CONVECTION HAS BEEN WEAKENING THE PAST HOUR OR SO
AS IT MOVES INTO MARGINALLY MORE STABLE AIR AND LESS DYNAMIC
FORCING.

SOUTHERN UTAH WILL SEE AN INCREASE IN CONVECTION THIS EVENING AS
THE UPPER LOW MOVES NORTHEAST INTO THE STATE. SOLID SYNOPTIC-
SCALE AND A FAVORABLE MOISTURE WILL PRODUCE POCKETS OF HEAVY
PRECIP OVERNIGHT ALONG THE NORTH AND WEST FLANKS OF THE LOW.

PRECIP WILL SHIFT INTO NORTHERN AND FAR WESTERN UTAH EARLY
SATURDAY. THE HEAVIEST PRECIP WILL REMAIN IN CLOSE PROXIMITY TO
THE UPPER LOW OVER NORTHEAST UTAH...WITH A SECONDARY AREA ACROSS
NORTHWEST UTAH IN ASSOCIATION WITH WARM ADVECTION GENERATED LIFT.
THIS THERMALLY DRIVEN LIFT WILL SLIDE SOUTH ALONG THE UTAH/NEVADA
BORDER DURING THE DAY...THEN FOCUS ON SOUTHWEST UTAH LATE
SATURDAY THROUGH EARLY SUNDAY. LOOKING AT ANOTHER ROUND OF
SIGNIFICANT PRECIP FOR THE SOUTH...ESPECIALLY DURING THE OVERNIGHT
HOURS SATURDAY.

RESIDUAL MOISTURE AND A COUPLE OF WEAK TRAILING SHORTWAVES BEHIND
THE EXITING UPPER LOW SHOULD PRODUCE ADDITIONAL SCATTERED
CONVECTION ACROSS NORTHERN AND WESTERN UTAH ON SUNDAY
AFTERNOON/EVENING. A TRAILING SHORTWAVE RIDGE WILL REACH UTAH ON
MONDAY...LIMITING THE AREAL COVERAGE OF ANY CONVECTION AND
CONFINING THIS TO MAINLY THE HIGHER TERRAIN THROUGH EARLY MONDAY
EVENING.

.LONG TERM (AFTER 06Z TUESDAY)...FEATURES TO FOCUS ON THROUGH THE
LONG TERM PERIOD ARE THE TRACK OF A REMNANT LOW AS IN MEANDERS
SOUTH AND EAST FROM BRITCOL INTO THE PACNW/NORTHERN ROCKIES...AND
WEAK SHORT WAVES TRANSLATING THROUGH THE DESERT SOUTHWEST
ASSOCIATED WITH THE SOUTHERN BRANCH JET. IN GENERAL THE
COMBINATION OF BOTH WILL MAINTAIN A GENERAL TROUGH OVER THE
EASTERN GREAT BASIN THROUGH THURSDAY...THIS ALLOWING UNSETTLED
CONDITIONS TO CONTINUE THROUGH LATE WEEK /ESPECIALLY ACROSS
NORTHERN AND CENTRAL PORTIONS/.

A COMBINATION OF CONDITIONAL INSTABILITY...MAINTENANCE OF DEEP LAYER
MOISTURE AND WEAK LARGE SCALE FORCING IS EXPECTED TO MAINTAIN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FOCUSED OVER THE
NORTHERN 2/3RDS OF THE AREA EACH DAY THROUGH WEDNESDAY. EXPECTING
COVERAGE OF THESE TO BE GREATEST ACROSS THE NORTH DUE TO CLOSER
PROXIMITY TO THE WEAK UPPER LOW TRANSLATING FROM THE PACNW INTO THE
NORTHERN ROCKIES. NOCTURNAL SHOWERS WILL REMAIN POSSIBLE DUE TO WEAK
FORCING AIDED BY PASSAGE OF WAVES ASSOCIATED WITHIN THE SOUTHERN
BRANCH.

GFS/ECMWF CONTINUE TO SLIGHTLY DIFFER IN DOWNSTREAM EVOLUTION OF THE
LOW TO THE NORTH...BUT DO BOTH SUGGEST THE MEAN TROUGH AXIS WILL
SWEEP EAST OF THE FORECAST AREA THURSDAY ALLOWING BUILDING STABILITY
AND NET DRYING FROM THE WEST. A MORE NOTED WARMING TREND LOOKS
LIKELY LATE WEEK DUE TO THIS AND ADJUSTED TEMPS UP A BIT TO ACCOUNT
FOR THIS.

&&

.AVIATION...ANTICIPATING THAT PERIODS OF ERRATIC WINDS DUE TO
PASSING SHOWERS WILL BE THE PRIMARY OPERATIONAL WEATHER CONCERN AT
THE KSLC TERMINAL THROUGH THIS EVENING. PREVAILING WINDS ARE
EXPECTED TO REMAIN GENERALLY LIGHT FROM THE WEST/NORTHWEST THROUGH
01/02Z...BUT OUTFLOWS FROM SHOWERS APPROACHING FROM THE SOUTHEAST
WILL LIKELY ALLOW SOUTHERLY WINDS TO RETURN EARLIER THAN NORMAL
AROUND 01/02Z.

&&

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

$$

SHORT TERM...CONGER
LONG TERM/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)





000
FXUS65 KSLC 221641
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1041 AM MDT FRI MAY 22 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OVER SOUTHERN CALIFORNIA
WILL TURN NORTHEAST AND TRACK NORTHEAST THROUGH THE SOUTHERN AND
EASTERN GREAT BASIN THIS WEEKEND.

&&

.DISCUSSION...THE UPPER LOW CURRENTLY OVER SOUTHERN CALIFORNIA
STILL ON TRACK TO TURN NORTHEAST AND SLOW CROSS SOUTHERN AND
EASTERN UTAH TONIGHT THROUGH SATURDAY EVENING. AHEAD OF THE UPPER
LOW AN AREA OF WEAK MOISTURE CONVERGENCE ACROSS NORTHERN UTAH HAS
PRODUCED WIDESPREAD CLOUD COVER AND POCKETS OF LIGHT PRECIP. THE
CONVERGENCE AREA WILL WEAKEN FURTHER THIS AFTERNOON AND WILL NOT
LIKELY BE THE SOURCE OF LIFT TO SUSTAIN PRECIP LATER TODAY.

MOSTLY CLEAR SKIES SOUTH BETWEEN THE UPPER LOW AND THE CONVERGENCE
ZONE SHOULD FILL IN QUICKLY WITH CONVECTIVE PRECIP AHEAD OF THE
ADVANCING UPPER LOW. TERRAIN-BASED CONVECTION HAS ALREADY FORMED
OVER THE SOUTHERN/CENTRAL MOUNTAINS...AND WILL CONTINUE TO
INCREASE IN AREAL COVERAGE AND INTENSITY SUPPORTED BY INCREASING
DYNAMIC LIFT AND WEAK UPPER DIVERGENCE NORTH OF THE LOW. THIS
CONVECTION WILL ALSO SPREAD NORTH ACROSS MUCH OF NORTHERN UTAH
DURING THE AFTERNOON. LOOKING AT THE POTENTIAL FOR HEAVY RAIN WITH
SOME OF THE STRONGER CONVECTIVE ELEMENTS. THE RELATIVELY SLOW
MOVEMENT OF THE STORMS WILL BRING THE POTENTIAL FOR LOCAL FLOODING
INTO PLAY FOR THE URBAN AREAS THIS AFTERNOON/EARLY EVENING.

A BROAD AREA OF SYNOPTIC-SCALE LIFT ASSOCIATED WITH THE UPPER LOW
WILL LEAD TO FAIRLY WIDESPREAD RAIN AND HIGH ELEVATION SNOWS OVER
THE WEEKEND. ON SATURDAY LOOKING AT THE HEAVIEST PRECIP IN CLOSE
PROXIMITY TO THE UPPER LOW AND THE ASSOCIATED COLD POOL ALOFT...
AND IN THE WARM ADVECTION WRAP AROUND BAND ACROSS FAR NORTHERN
THROUGH WEST-CENTRAL UTAH.

THE BIGGEST QUESTION MARK IN TERMS OF SIGNIFICANT PRECIP WILL BE
ALONG THE URBAN CORRIDOR OF NORTHERN UTAH. LOOKING AT ONLY A
BRIEF PERIOD OF NORTH-NORTHWEST WARM ADVECTION ON SATURDAY...
FOLLOWING BY WEAK EASTERLY COLD ADVECTION LATE AFTERNOON/EVENING.
THIS SWITCH IN THE THERMAL ADVECTION COULD DEVELOP A WEAK
DOWNSLOPE FLOW AND SIGNIFICANT REDUCE THE INTENSITY OF THE PRECIP.
FOR NOW WILL LOWER THE QPFS ACROSS THE URBAN CORRIDOR...THOUGH NOT
ENTIRELY END PRECIP AS THE LOCAL DOWNSLOPE FLOW WILL BE WEAK AND
ENOUGH SYNOPTIC-SCALE WILL STILL EXIST TO KEEP LIGHT PRECIP GOING
THROUGH EARLY SUNDAY.

SOUTHWEST UTAH COULD BECOME THE FOCUS FOR HEAVY PRECIP LATE
SATURDAY THROUGH EARLY SUNDAY. THE MOIST NORTHWEST WARM ADVECTION
PATTERN SETTING UP SHOULD GENERATE SUBSTANTIAL LIFT AND PRODUCE
AREAS OF MODERATE OR EVEN HEAVY PRECIP ALONG THE I-15 CORRIDOR AND
INTO THE MOUNTAINS TO THE EAST.

FOR MEMORIAL DAY MORE THAN ENOUGH RESIDUAL MOISTURE WILL EXIST FOR
SCATTERED CONVECTIVE PRECIP DURING THE DAY. THE SHORTWAVE RIDGE
SCHEDULED TO FOLLOW LATER IN THE DAY SHOULD BRING AN END TO MOST
PRECIP BY MONDAY EVENING.

&&

.AVIATION...CEILINGS WILL GENERALLY REMAIN ABOVE 6000 FT AGL
THROUGH THE DAY. SHOWERS DEVELOPING THIS AFTERNOON MAY BRING
CEILINGS TO OR BELOW THAT VALUE AT TIMES. SOUTHERLY WINDS ARE
EXPECTED TO PREVAIL...BUT SHOWERS COULD PRODUCE PERIODS OF GUSTY
AND/OR ERRATIC WINDS AT TIMES.

&&

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

$$

PUBLIC...CONGER
AVIATION...RUTZ/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)




000
FXUS65 KSLC 221641
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1041 AM MDT FRI MAY 22 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OVER SOUTHERN CALIFORNIA
WILL TURN NORTHEAST AND TRACK NORTHEAST THROUGH THE SOUTHERN AND
EASTERN GREAT BASIN THIS WEEKEND.

&&

.DISCUSSION...THE UPPER LOW CURRENTLY OVER SOUTHERN CALIFORNIA
STILL ON TRACK TO TURN NORTHEAST AND SLOW CROSS SOUTHERN AND
EASTERN UTAH TONIGHT THROUGH SATURDAY EVENING. AHEAD OF THE UPPER
LOW AN AREA OF WEAK MOISTURE CONVERGENCE ACROSS NORTHERN UTAH HAS
PRODUCED WIDESPREAD CLOUD COVER AND POCKETS OF LIGHT PRECIP. THE
CONVERGENCE AREA WILL WEAKEN FURTHER THIS AFTERNOON AND WILL NOT
LIKELY BE THE SOURCE OF LIFT TO SUSTAIN PRECIP LATER TODAY.

MOSTLY CLEAR SKIES SOUTH BETWEEN THE UPPER LOW AND THE CONVERGENCE
ZONE SHOULD FILL IN QUICKLY WITH CONVECTIVE PRECIP AHEAD OF THE
ADVANCING UPPER LOW. TERRAIN-BASED CONVECTION HAS ALREADY FORMED
OVER THE SOUTHERN/CENTRAL MOUNTAINS...AND WILL CONTINUE TO
INCREASE IN AREAL COVERAGE AND INTENSITY SUPPORTED BY INCREASING
DYNAMIC LIFT AND WEAK UPPER DIVERGENCE NORTH OF THE LOW. THIS
CONVECTION WILL ALSO SPREAD NORTH ACROSS MUCH OF NORTHERN UTAH
DURING THE AFTERNOON. LOOKING AT THE POTENTIAL FOR HEAVY RAIN WITH
SOME OF THE STRONGER CONVECTIVE ELEMENTS. THE RELATIVELY SLOW
MOVEMENT OF THE STORMS WILL BRING THE POTENTIAL FOR LOCAL FLOODING
INTO PLAY FOR THE URBAN AREAS THIS AFTERNOON/EARLY EVENING.

A BROAD AREA OF SYNOPTIC-SCALE LIFT ASSOCIATED WITH THE UPPER LOW
WILL LEAD TO FAIRLY WIDESPREAD RAIN AND HIGH ELEVATION SNOWS OVER
THE WEEKEND. ON SATURDAY LOOKING AT THE HEAVIEST PRECIP IN CLOSE
PROXIMITY TO THE UPPER LOW AND THE ASSOCIATED COLD POOL ALOFT...
AND IN THE WARM ADVECTION WRAP AROUND BAND ACROSS FAR NORTHERN
THROUGH WEST-CENTRAL UTAH.

THE BIGGEST QUESTION MARK IN TERMS OF SIGNIFICANT PRECIP WILL BE
ALONG THE URBAN CORRIDOR OF NORTHERN UTAH. LOOKING AT ONLY A
BRIEF PERIOD OF NORTH-NORTHWEST WARM ADVECTION ON SATURDAY...
FOLLOWING BY WEAK EASTERLY COLD ADVECTION LATE AFTERNOON/EVENING.
THIS SWITCH IN THE THERMAL ADVECTION COULD DEVELOP A WEAK
DOWNSLOPE FLOW AND SIGNIFICANT REDUCE THE INTENSITY OF THE PRECIP.
FOR NOW WILL LOWER THE QPFS ACROSS THE URBAN CORRIDOR...THOUGH NOT
ENTIRELY END PRECIP AS THE LOCAL DOWNSLOPE FLOW WILL BE WEAK AND
ENOUGH SYNOPTIC-SCALE WILL STILL EXIST TO KEEP LIGHT PRECIP GOING
THROUGH EARLY SUNDAY.

SOUTHWEST UTAH COULD BECOME THE FOCUS FOR HEAVY PRECIP LATE
SATURDAY THROUGH EARLY SUNDAY. THE MOIST NORTHWEST WARM ADVECTION
PATTERN SETTING UP SHOULD GENERATE SUBSTANTIAL LIFT AND PRODUCE
AREAS OF MODERATE OR EVEN HEAVY PRECIP ALONG THE I-15 CORRIDOR AND
INTO THE MOUNTAINS TO THE EAST.

FOR MEMORIAL DAY MORE THAN ENOUGH RESIDUAL MOISTURE WILL EXIST FOR
SCATTERED CONVECTIVE PRECIP DURING THE DAY. THE SHORTWAVE RIDGE
SCHEDULED TO FOLLOW LATER IN THE DAY SHOULD BRING AN END TO MOST
PRECIP BY MONDAY EVENING.

&&

.AVIATION...CEILINGS WILL GENERALLY REMAIN ABOVE 6000 FT AGL
THROUGH THE DAY. SHOWERS DEVELOPING THIS AFTERNOON MAY BRING
CEILINGS TO OR BELOW THAT VALUE AT TIMES. SOUTHERLY WINDS ARE
EXPECTED TO PREVAIL...BUT SHOWERS COULD PRODUCE PERIODS OF GUSTY
AND/OR ERRATIC WINDS AT TIMES.

&&

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

$$

PUBLIC...CONGER
AVIATION...RUTZ/KRUSE

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
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000
FXUS65 KSLC 220908
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
308 AM MDT FRI MAY 22 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OVER SOUTHERN CALIFORNIA
WILL TURN NORTHEAST AND SLOWLY TRACK NORTHEAST THROUGH THE GREAT
BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 12Z MONDAY)...
WATER VAPOR LOOP SHOWS A CLOSED OVER SOUTHERN CALIFORNIA. AMDAR
400- 250MB WIND OBSERVATIONS SHOW A 75-110KT CYCLONIC JET FROM THE
EASTERN PACIFIC INTO THE SOUTHERN ROCKIES. GOES/GPS/RAP/00Z SLC
RAOB INDICATE THE PRECIPITABLE WATER VALUE RANGES BETWEEN
0.25"-0.50" MOUNTAINS...TO 0.50"-0.75" ACROSS THE VALLEYS.

MAIN FEATURE THIS MORNING IS A SHORTWAVE PIVOTING FROM EAST CENTRAL
UTAH LATE OVERNIGHT...INTO SOUTHWEST WYOMING AND NORTHEAST UTAH THIS
AFTERNOON. DEFORMATION ZONE WILL BUILD INTO WESTERN UTAH THIS
AFTERNOON...WITH BETTER DEEP LAYER SHEAR CONFINED DOWNWIND OF THE
TROUGH OVER THE FOUR CORNERS. THESE FEATURES WILL COMBINE WITH
MODEST INSTABILITY TO ONCE AGAIN SUPPORT SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS THROUGH THE EVENING HOURS.

GREATEST DCAPE SHOULD BE SOUTH OF INTERSTATE 80 DUE TO DRIER LOW
LEVELS...SUPPORTING A HIGHER CHANCE FOR DRY MICROBURSTS. OTHERWISE
STORMS WILL ALSO CONTAIN CLOUD TO GROUND LIGHTNING...SMALL
HAIL...AND A BRIEF HEAVY RAIN.

EXPECTING DEFORMATION ZONE TO SUPPORT GREATER STORM COVERAGE
OVERNIGHT.

THE BEST COVERAGE OF RAIN IS LIKELY SATURDAY INTO SATURDAY NIGHT
WHEN WRAP-AROUND PRECIPITATION DUE TO MID LEVEL WARM ADVECTION
ARRIVES FROM THE NORTHEAST. GLOBAL MODELS ARE BEGINNING TO FOCUS IN
ON NW UTAH SATURDAY MORNING...THEN DOWN THE NEVADA BORDER REGION
TOWARD DELTA AND CEDAR CITY SATURDAY AFTERNOON...AND SOUTHWEST/SOUTH
CENTRAL UTAH SATURDAY EVENING. RE-FOCUSED POPS TO THESE AREAS WITH
THIS IN MIND.

CONVECTIVE COVERAGE SHOULD DECAY SATURDAY NIGHT INTO SUNDAY MORNING
AS THE CLOSED LOW LIFTS INTO THE CENTRAL ROCKIES DUE TO AN UPSTREAM
WAVE SINKING SOUTH OVER CALIFORNIA. WHILE THIS FEATURE DOES NOT PASS
OVERHEAD SUNDAY...COMBINATION OF MODEST INSTABILITY AND A NEW AREA
OF DEFORMATION BETWEEN THESE SYSTEMS WILL LIKELY LEAD TO ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON AND EVENING.
DECAY THE ACTIVITY FROM NW TO SE OVERNIGHT SUNDAY WITH INFUSION OF
DRIER AIR ALOFT ON DRYING NORTHWEST FLOW AS RIDGING BUILDS IN OVER
NEVADA.

.LONG TERM (AFTER 12Z MONDAY)...
UNSETTLED PATTERN LOOKS TO CONTINUE TO REMAIN IN PLACE DURING THE
UPCOMING WEEK. A PACIFIC TROUGH WILL DIG INTO ARIZONA MONDAY
MORNING BEFORE CROSSING INTO NEW MEXICO MONDAY EVENING...PROVIDING
INSTABILITY OVER THE FORECAST AREA. A MORE ZONAL FLOW IS PROGGED
TO DEVELOP FOR TUESDAY...BUT LINGERING MOISTURE AND INSTABILITY
WILL PROVIDE FUEL FOR AFTERNOON SHOWERS AND
THUNDERSTORMS...PARTICULARLY OVER THE HIGHER TERRAIN OF NORTHERN
UTAH.

SOME DIFFERENCES REMAIN IN THE GLOBAL MODELS WITH THE HANDLING OF
THE PACIFIC NORTHWEST STORM SYSTEM THAT APPROACHES AFTER THIS.
GFS/EC BOTH MOVE THE SYSTEM ONSHORE OVER WASHINGTON MONDAY NIGHT BUT
IN THE LATEST EC THIS TRACKS EAST NEAR THE UNITED STATES/CANADA
BORDER AS IT WEAKENS THROUGH THE MIDDLE OF THE WEEK...BRINGING A
PUSH OF MOISTURE INTO NORTHERN AND CENTRAL UTAH FOR WEDNESDAY AND
THURSDAY BEFORE DRIER AIR MOVES IN FOR DAY 7. THE PROGRESSION OF THE
SYSTEM IS A BIT SLOWER IN THE GFS...AS THE SYSTEM REMAINS STALLED
OVER WASHINGTON AND OREGON THROUGH THURSDAY BEFORE FINALLY MOVING
EAST AND WEAKENING ON FRIDAY. THIS WOULD KEEP MOISTURE OVER NORTHERN
UTAH...BUT WOULD RESULT IN A SOMEWHAT DRIER SOLUTION FOR CENTRAL AND
SOUTHERN UTAH. FOR NOW...HAVE OPTED TO KEEP POPS AROUND TO A BIT
ABOVE CLIMO GIVEN THAT ALL GUIDANCE IS CONTINUING TO INDICATE AT
LEAST A SOMEWHAT MOIST AND UNSTABLE PATTERN.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT THE SLC TERMINAL
THROUGHOUT THE DAY. CIGS WILL GENERALLY REMAIN ABOVE 6000 FT
AGL...BUT SHOWERS DEVELOPING THIS AFTERNOON WILL LIKELY BRING CIGS
TO OR BELOW THAT VALUE FOR PERIODS. SOUTHERLY WINDS ARE EXPECTED TO
PREVAIL...BUT THE SHOWERS WILL PRODUCE PERIODS OF GUSTY AND/OR
ERRATIC WINDS.

&&

.FIRE WEATHER...THE NEXT STORM SYSTEM ARRIVES TODAY AND PERSISTS
THROUGH THE HOLIDAY WEEKEND. SHOWERS AND THUNDERSTORMS WILL GROW
MORE NUMEROUS ACROSS THE REGION...WITH THE GREATEST COVERAGE IN
ACTIVITY EXPECTED SATURDAY...ESPECIALLY ACROSS WESTERN AND SOUTHERN
UTAH. TEMPERATURES WILL TREND COOLER AND HUMIDITY WILL TREND HIGHER.
SNOW LEVELS WILL BE BETWEEN 8-9KFT...FALLING TO 7KFT UNDER THE
HEAVIEST ACTIVITY. CLOUD TO GROUND LIGHTNING...GUSTY/ERRATIC
WINDS...A BRIEF HEAVY DOWNPOUR...AND SMALL HAIL ARE ALL POSSIBLE
WITH THE STRONGER ACTIVITY.

&&

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

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...TRAPHAGAN

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
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VISIT...
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000
FXUS65 KSLC 220908
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
308 AM MDT FRI MAY 22 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OVER SOUTHERN CALIFORNIA
WILL TURN NORTHEAST AND SLOWLY TRACK NORTHEAST THROUGH THE GREAT
BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 12Z MONDAY)...
WATER VAPOR LOOP SHOWS A CLOSED OVER SOUTHERN CALIFORNIA. AMDAR
400- 250MB WIND OBSERVATIONS SHOW A 75-110KT CYCLONIC JET FROM THE
EASTERN PACIFIC INTO THE SOUTHERN ROCKIES. GOES/GPS/RAP/00Z SLC
RAOB INDICATE THE PRECIPITABLE WATER VALUE RANGES BETWEEN
0.25"-0.50" MOUNTAINS...TO 0.50"-0.75" ACROSS THE VALLEYS.

MAIN FEATURE THIS MORNING IS A SHORTWAVE PIVOTING FROM EAST CENTRAL
UTAH LATE OVERNIGHT...INTO SOUTHWEST WYOMING AND NORTHEAST UTAH THIS
AFTERNOON. DEFORMATION ZONE WILL BUILD INTO WESTERN UTAH THIS
AFTERNOON...WITH BETTER DEEP LAYER SHEAR CONFINED DOWNWIND OF THE
TROUGH OVER THE FOUR CORNERS. THESE FEATURES WILL COMBINE WITH
MODEST INSTABILITY TO ONCE AGAIN SUPPORT SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS THROUGH THE EVENING HOURS.

GREATEST DCAPE SHOULD BE SOUTH OF INTERSTATE 80 DUE TO DRIER LOW
LEVELS...SUPPORTING A HIGHER CHANCE FOR DRY MICROBURSTS. OTHERWISE
STORMS WILL ALSO CONTAIN CLOUD TO GROUND LIGHTNING...SMALL
HAIL...AND A BRIEF HEAVY RAIN.

EXPECTING DEFORMATION ZONE TO SUPPORT GREATER STORM COVERAGE
OVERNIGHT.

THE BEST COVERAGE OF RAIN IS LIKELY SATURDAY INTO SATURDAY NIGHT
WHEN WRAP-AROUND PRECIPITATION DUE TO MID LEVEL WARM ADVECTION
ARRIVES FROM THE NORTHEAST. GLOBAL MODELS ARE BEGINNING TO FOCUS IN
ON NW UTAH SATURDAY MORNING...THEN DOWN THE NEVADA BORDER REGION
TOWARD DELTA AND CEDAR CITY SATURDAY AFTERNOON...AND SOUTHWEST/SOUTH
CENTRAL UTAH SATURDAY EVENING. RE-FOCUSED POPS TO THESE AREAS WITH
THIS IN MIND.

CONVECTIVE COVERAGE SHOULD DECAY SATURDAY NIGHT INTO SUNDAY MORNING
AS THE CLOSED LOW LIFTS INTO THE CENTRAL ROCKIES DUE TO AN UPSTREAM
WAVE SINKING SOUTH OVER CALIFORNIA. WHILE THIS FEATURE DOES NOT PASS
OVERHEAD SUNDAY...COMBINATION OF MODEST INSTABILITY AND A NEW AREA
OF DEFORMATION BETWEEN THESE SYSTEMS WILL LIKELY LEAD TO ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON AND EVENING.
DECAY THE ACTIVITY FROM NW TO SE OVERNIGHT SUNDAY WITH INFUSION OF
DRIER AIR ALOFT ON DRYING NORTHWEST FLOW AS RIDGING BUILDS IN OVER
NEVADA.

.LONG TERM (AFTER 12Z MONDAY)...
UNSETTLED PATTERN LOOKS TO CONTINUE TO REMAIN IN PLACE DURING THE
UPCOMING WEEK. A PACIFIC TROUGH WILL DIG INTO ARIZONA MONDAY
MORNING BEFORE CROSSING INTO NEW MEXICO MONDAY EVENING...PROVIDING
INSTABILITY OVER THE FORECAST AREA. A MORE ZONAL FLOW IS PROGGED
TO DEVELOP FOR TUESDAY...BUT LINGERING MOISTURE AND INSTABILITY
WILL PROVIDE FUEL FOR AFTERNOON SHOWERS AND
THUNDERSTORMS...PARTICULARLY OVER THE HIGHER TERRAIN OF NORTHERN
UTAH.

SOME DIFFERENCES REMAIN IN THE GLOBAL MODELS WITH THE HANDLING OF
THE PACIFIC NORTHWEST STORM SYSTEM THAT APPROACHES AFTER THIS.
GFS/EC BOTH MOVE THE SYSTEM ONSHORE OVER WASHINGTON MONDAY NIGHT BUT
IN THE LATEST EC THIS TRACKS EAST NEAR THE UNITED STATES/CANADA
BORDER AS IT WEAKENS THROUGH THE MIDDLE OF THE WEEK...BRINGING A
PUSH OF MOISTURE INTO NORTHERN AND CENTRAL UTAH FOR WEDNESDAY AND
THURSDAY BEFORE DRIER AIR MOVES IN FOR DAY 7. THE PROGRESSION OF THE
SYSTEM IS A BIT SLOWER IN THE GFS...AS THE SYSTEM REMAINS STALLED
OVER WASHINGTON AND OREGON THROUGH THURSDAY BEFORE FINALLY MOVING
EAST AND WEAKENING ON FRIDAY. THIS WOULD KEEP MOISTURE OVER NORTHERN
UTAH...BUT WOULD RESULT IN A SOMEWHAT DRIER SOLUTION FOR CENTRAL AND
SOUTHERN UTAH. FOR NOW...HAVE OPTED TO KEEP POPS AROUND TO A BIT
ABOVE CLIMO GIVEN THAT ALL GUIDANCE IS CONTINUING TO INDICATE AT
LEAST A SOMEWHAT MOIST AND UNSTABLE PATTERN.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT THE SLC TERMINAL
THROUGHOUT THE DAY. CIGS WILL GENERALLY REMAIN ABOVE 6000 FT
AGL...BUT SHOWERS DEVELOPING THIS AFTERNOON WILL LIKELY BRING CIGS
TO OR BELOW THAT VALUE FOR PERIODS. SOUTHERLY WINDS ARE EXPECTED TO
PREVAIL...BUT THE SHOWERS WILL PRODUCE PERIODS OF GUSTY AND/OR
ERRATIC WINDS.

&&

.FIRE WEATHER...THE NEXT STORM SYSTEM ARRIVES TODAY AND PERSISTS
THROUGH THE HOLIDAY WEEKEND. SHOWERS AND THUNDERSTORMS WILL GROW
MORE NUMEROUS ACROSS THE REGION...WITH THE GREATEST COVERAGE IN
ACTIVITY EXPECTED SATURDAY...ESPECIALLY ACROSS WESTERN AND SOUTHERN
UTAH. TEMPERATURES WILL TREND COOLER AND HUMIDITY WILL TREND HIGHER.
SNOW LEVELS WILL BE BETWEEN 8-9KFT...FALLING TO 7KFT UNDER THE
HEAVIEST ACTIVITY. CLOUD TO GROUND LIGHTNING...GUSTY/ERRATIC
WINDS...A BRIEF HEAVY DOWNPOUR...AND SMALL HAIL ARE ALL POSSIBLE
WITH THE STRONGER ACTIVITY.

&&

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

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...TRAPHAGAN

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

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VISIT...
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000
FXUS65 KSLC 220338
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
938 PM MDT THU MAY 21 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
MOVE INLAND TONIGHT...THEN TURN NORTHEAST AND SLOWLY TRACK NORTHEAST
THROUGH THE GREAT BASIN THIS WEEKEND.

&&

.DISCUSSION...AN UPPER LEVEL LOW CENTERED OVER THE CENTRAL/SOUTHERN
CALIFORNIA COAST THIS EVENING WILL CONTINUE TO TRACK SOUTHEAST
OVERNIGHT. DOWNSTREAM OF THIS SYSTEM...UTAH REMAINS UNDER A
SOUTHERLY FLOW ALOFT. CONVECTIVE STORMS...DRIVEN MAINLY BY A WEAK
SHORTWAVE DISTURBANCES LIFTING THROUGH THE AREA AND MEAN DIFFLUENT
FLOW ALOFT IS STRONGEST CURRENTLY OVER PORTIONS OF NORTHERN UTAH. AS
THE WAVE DRIVING THIS EXITS NORTH...EXPECT ACTIVITY TO DECREASE
OVERNIGHT. HOWEVER...ANOTHER WEAK DISTURBANCE IS EVIDENT ACROSS
NORTHEAST ARIZONA AT THIS TIME AND IS PROGGED TO LIFT ACROSS EASTERN
UTAH...SPREADING ASSOCIATED PRECIPITATION THROUGH THIS AREA TONIGHT
INTO TOMORROW MORNING.

THE UPPER LOW IS PROGGED TO CROSS THE LAKE MEAD AREA LATE TOMORROW
AFTERNOON BEFORE LIFTING NORTHEAST ACROSS SOUTHERN/EASTERN UTAH.
EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP AGAIN ACROSS MUCH OF THE
AREA OWING TO THE SOMEWHAT MOIST AND UNSTABLE AIRMASS AND LARGE-
SCALE LIFT AHEAD OF THE LOW. HOWEVER...SATURDAY WILL BE POTENTIALLY
MORE WET AS MOISTURE WRAPS AROUND THE LOW AS IT TRACKS INTO
COLORADO/WYOMING.

UPDATED FORECAST MAINLY TO ADJUST POP/SKY FOR THE REMAINDER OF THE
NIGHT.

&&

.AVIATION...SOUTHWESTERLY WINDS WILL BECOME ESTABLISHED AT THE KSLC
TERMINAL BY 04Z. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO PREVAIL
THROUGH THE NIGHT WITH CIGS ABOVE 7000FT AGL. THERE IS A 10 PERCENT
CHANCE OF SHOWERS LOWERING CIGS BELOW 7000FT AGAIN OVERNIGHT.

&&


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

$$

CHENG

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

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VISIT...
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000
FXUS65 KSLC 220338
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
938 PM MDT THU MAY 21 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
MOVE INLAND TONIGHT...THEN TURN NORTHEAST AND SLOWLY TRACK NORTHEAST
THROUGH THE GREAT BASIN THIS WEEKEND.

&&

.DISCUSSION...AN UPPER LEVEL LOW CENTERED OVER THE CENTRAL/SOUTHERN
CALIFORNIA COAST THIS EVENING WILL CONTINUE TO TRACK SOUTHEAST
OVERNIGHT. DOWNSTREAM OF THIS SYSTEM...UTAH REMAINS UNDER A
SOUTHERLY FLOW ALOFT. CONVECTIVE STORMS...DRIVEN MAINLY BY A WEAK
SHORTWAVE DISTURBANCES LIFTING THROUGH THE AREA AND MEAN DIFFLUENT
FLOW ALOFT IS STRONGEST CURRENTLY OVER PORTIONS OF NORTHERN UTAH. AS
THE WAVE DRIVING THIS EXITS NORTH...EXPECT ACTIVITY TO DECREASE
OVERNIGHT. HOWEVER...ANOTHER WEAK DISTURBANCE IS EVIDENT ACROSS
NORTHEAST ARIZONA AT THIS TIME AND IS PROGGED TO LIFT ACROSS EASTERN
UTAH...SPREADING ASSOCIATED PRECIPITATION THROUGH THIS AREA TONIGHT
INTO TOMORROW MORNING.

THE UPPER LOW IS PROGGED TO CROSS THE LAKE MEAD AREA LATE TOMORROW
AFTERNOON BEFORE LIFTING NORTHEAST ACROSS SOUTHERN/EASTERN UTAH.
EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP AGAIN ACROSS MUCH OF THE
AREA OWING TO THE SOMEWHAT MOIST AND UNSTABLE AIRMASS AND LARGE-
SCALE LIFT AHEAD OF THE LOW. HOWEVER...SATURDAY WILL BE POTENTIALLY
MORE WET AS MOISTURE WRAPS AROUND THE LOW AS IT TRACKS INTO
COLORADO/WYOMING.

UPDATED FORECAST MAINLY TO ADJUST POP/SKY FOR THE REMAINDER OF THE
NIGHT.

&&

.AVIATION...SOUTHWESTERLY WINDS WILL BECOME ESTABLISHED AT THE KSLC
TERMINAL BY 04Z. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO PREVAIL
THROUGH THE NIGHT WITH CIGS ABOVE 7000FT AGL. THERE IS A 10 PERCENT
CHANCE OF SHOWERS LOWERING CIGS BELOW 7000FT AGAIN OVERNIGHT.

&&


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

$$

CHENG

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

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VISIT...
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000
FXUS65 KSLC 212218
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
418 PM MDT THU MAY 21 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
MOVE INLAND TONIGHT...THEN TURN NORTHEAST AND SLOWLY TRACK NORTHEAST
THROUGH THE GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z MONDAY)...THE UPPER LOW CENTERED JUST OFF
THE CENTRAL CALIFORNIA COAST THIS AFTERNOON WILL TAKE A TURN TO
THE EAST-SOUTHEAST INTO SOUTHERN CALIFORNIA LATER TONIGHT. FROM
THERE THIS LOW WILL MOVE INTO NORTHWEST ARIZONA FRIDAY NIGHT...
THEN TURN TO THE NORTHEAST AND TRACK SLOWLY THROUGH THE SOUTHERN
AND EASTERN GREAT BASIN THIS WEEKEND.

AHEAD OF THIS UPPER LOW AT LEAST TWO OR THREE VORTICITY LOBE WILL
EJECT OUT OF THE PARENT LOW AND TRACK NORTH ACROSS UTAH TONIGHT
THROUGH EARLY FRIDAY. THIS DYNAMIC SUPPORT FOR LIFT WORKING WITH
THE FAIRLY MOIST AND UNSTABLE AIR MASS ALREADY IN PLACE WILL
PRODUCE PERIODIC SHOWERS/THUNDERSTORMS. GOOD UPPER DIVERGENCE WILL
ALSO SUPPORT DEEP CONVECTION CAPABLE OF PRODUCING HEAVY
RAIN/SMALL HAIL WITH THE STRONG CONVECTIVE ELEMENTS.

THE SLOW NORTHEAST PROGRESSION OF THE UPPER LOW THROUGH SOUTHERN
AND EASTERN UTAH WILL LEAD TO A PROLONGED PERIOD OF VALLEY RAIN
AND HIGH ELEVATION SNOW THIS WEEKEND. SOLID SYNOPTIC-SCALE LIFT
AND MORE THE ADEQUATE MOISTURE SHOULD HAVE LITTLE TROUBLE GENERATE
WIDESPREAD PRECIPITATION BEGINNING LATE FRIDAY NIGHT AND
CONTINUING INTO AT LEAST SATURDAY EVENING.

WILL CONCENTRATE THE HEAVIEST PRECIP IN THE AREAS NORTH AND WEST
OF THE UPPER LOW WHERE DEEP LAYER AND MOIST WARM ADVECTION WRAP
AROUND EXISTS. THESE AREAS OF THERMALLY-DRIVEN LIFT HAVE BEEN
RATHER PROLIFIC IN THE AMOUNT OF PRECIP GENERATED IN RECENT
STORMS...AND SEE NO GOOD REASON TO DEVIATE FROM THIS THINKING AT
THIS TIME. QUESTION RIGHT NOW IS WHICH MODEL...EITHER THE GFS OR
THE ECMWF...IS THE ONE TO FOLLOW WITH THIS STORM. THE MAIN
DIFFERENCE COMES WITH THE ORIENTATION OF THE WARM ADVECTION. THE
GFS MAINTAINS A MORE NORTH-NORTHWEST ORIENTATION WITH FAIRLY
STRONG THERMAL ADVECTION INTO AND WEST OF THE WASATCH RANGE
SATURDAY. THE ECMWF IN CONTRAST HAS SOME EASTERLY COMPONENT TO THE
ADVECTION WHICH WOULD FOCUS CLOSER TO THE NEVADA BORDER. THE TRACK
OF THE UPPER LOW...THOUGH FAIRLY SIMILAR IN BOTH MODEL...WOULD
TEND TO SUPPORT THE ECMWF MORE THAN THE GFS. THE CURRENT FORECAST
WOULD STILL MAINTAIN WIDESPREAD AND SUBSTANTIAL PRECIP...THOUGH
QPFS WILL BE SCALED DOWN A BIT ALONG THE URBAN CORRIDOR IN THE
THIS FORECAST PACKAGE.


.LONG TERM (AFTER 06Z MONDAY)...SIMILAR DIFFERENCES EXIST REGARDING
SHORT WAVE EVOLUTION ACROSS THE WESTERN CONUS IN THE LATEST 12Z RUNS
AS THE PREVIOUS FEW. BOTTOM LINE HOWEVER WILL CONTINUE TO FOCUS ON
UNSETTLED WEATHER ACROSS THE AREA AS A MEAN LONG WAVE WILL REMAIN IN
PLACE ACROSS THE WESTERN CONUS THROUGH THE PERIOD.

PRIMARY DIFFERENCE TO BEGIN THE LONG TERM PERIOD REVOLVES AROUND THE
HANDLING OF CUT OFF LOW THAT IS CURRENTLY SPINNING ALONG THE BRITCOL
COASTLINE /AND WILL REMAIN DOING SO FOR THE NEXT FEW DAYS/. THE GFS
CONTINUES TO WANT TO SHEAR A PORTION OF THIS LOBE SOUTHEAST OVER THE
WEEKEND AND INTO OUR AREA EARLY MONDAY MORNING KICKING THE PREVIOUS
UPPER LOW EAST. ECMWF CONTINUES TO TAKE THIS ENERGY IN A MORE LESS
CONSOLIDATED STATE TO OUR WEST...ROTATING IT THROUGH THE BASE OF THE
LONGWAVE. ALTHOUGH BOTH RETAIN FAIRLY WET SOLUTIONS...CONFIDENCE IS
LOW REGARDING PLACEMENT AND POTENTIAL SIGNIFICANCE OF PRECIP ATTM...
BUT FELT IT REASONABLE TO CONTINUE AN INCREASING TREND TO POPS
MONDAY /ESPECIALLY NORTH/.

THEREAFTER MODEL SPREAD ACTUALLY DECREASES THROUGH MIDWEEK. THE
GFS/ECMWF BOTH INDICATE TO SOME REGARD THE PRIMARY BRITCOL LOBE WILL
THEN MEANDER SLOWLY SOUTHEAST AND MERGE WITH A WEAK SOUTHERN BRANCH
SHORT WAVE THAT WILL BE UNDERCUTTING THE MEAN EASTERN PACIFIC RIDGE.
ALTHOUGH HEIGHTS WILL BE ATTEMPTING TO BUILD FROM THE SOUTHEAST AND
SOME WARMING OF TEMPS LOOKS LIKELY...VICINITY OF THESE FEATURES AND
RATHER DEEP MOISTURE IN PLACE NOW LOOKS TO MAINTAIN A GOOD CHANCE OF
FAIRLY WIDESPREAD CONVECTION ACROSS THE NORTHERN HALF OF THE AREA
FOR THE MIDWEEK PERIOD. OPTED TO BUMP POPS BOTH TUE/WED AS SUCH.

&&

.AVIATION...SOUTHWESTERLY WINDS THAT WILL BE GUSTY AT TIMES ARE
EXPECTED TO PREVAIL AT THE KSLC TERMINAL FOR THE NEXT FEW HOURS.
ANOTHER BAND OF IS SHOWERS APPROACHING FROM THE SOUTH AND WILL MOVE
THROUGH THE TERMINAL BY 2330Z BRINGING LIGHT RAIN SHOWERS...AIDING
TO MAINTAIN THIS WIND DIRECTION. UPON PASSAGE OF THESE SHOWERS TO
THE NORTH WINDS ARE EXPECTED TO RETURN TO THE NORTHWEST FOR THE
01Z TO 03Z WINDOW...BEFORE AGAIN RETURNING TO THE SOUTH OVERNIGHT.

&&


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

$$

SHORT TERM...CONGER
LONG TERM/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)




000
FXUS65 KSLC 212218
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
418 PM MDT THU MAY 21 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
MOVE INLAND TONIGHT...THEN TURN NORTHEAST AND SLOWLY TRACK NORTHEAST
THROUGH THE GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z MONDAY)...THE UPPER LOW CENTERED JUST OFF
THE CENTRAL CALIFORNIA COAST THIS AFTERNOON WILL TAKE A TURN TO
THE EAST-SOUTHEAST INTO SOUTHERN CALIFORNIA LATER TONIGHT. FROM
THERE THIS LOW WILL MOVE INTO NORTHWEST ARIZONA FRIDAY NIGHT...
THEN TURN TO THE NORTHEAST AND TRACK SLOWLY THROUGH THE SOUTHERN
AND EASTERN GREAT BASIN THIS WEEKEND.

AHEAD OF THIS UPPER LOW AT LEAST TWO OR THREE VORTICITY LOBE WILL
EJECT OUT OF THE PARENT LOW AND TRACK NORTH ACROSS UTAH TONIGHT
THROUGH EARLY FRIDAY. THIS DYNAMIC SUPPORT FOR LIFT WORKING WITH
THE FAIRLY MOIST AND UNSTABLE AIR MASS ALREADY IN PLACE WILL
PRODUCE PERIODIC SHOWERS/THUNDERSTORMS. GOOD UPPER DIVERGENCE WILL
ALSO SUPPORT DEEP CONVECTION CAPABLE OF PRODUCING HEAVY
RAIN/SMALL HAIL WITH THE STRONG CONVECTIVE ELEMENTS.

THE SLOW NORTHEAST PROGRESSION OF THE UPPER LOW THROUGH SOUTHERN
AND EASTERN UTAH WILL LEAD TO A PROLONGED PERIOD OF VALLEY RAIN
AND HIGH ELEVATION SNOW THIS WEEKEND. SOLID SYNOPTIC-SCALE LIFT
AND MORE THE ADEQUATE MOISTURE SHOULD HAVE LITTLE TROUBLE GENERATE
WIDESPREAD PRECIPITATION BEGINNING LATE FRIDAY NIGHT AND
CONTINUING INTO AT LEAST SATURDAY EVENING.

WILL CONCENTRATE THE HEAVIEST PRECIP IN THE AREAS NORTH AND WEST
OF THE UPPER LOW WHERE DEEP LAYER AND MOIST WARM ADVECTION WRAP
AROUND EXISTS. THESE AREAS OF THERMALLY-DRIVEN LIFT HAVE BEEN
RATHER PROLIFIC IN THE AMOUNT OF PRECIP GENERATED IN RECENT
STORMS...AND SEE NO GOOD REASON TO DEVIATE FROM THIS THINKING AT
THIS TIME. QUESTION RIGHT NOW IS WHICH MODEL...EITHER THE GFS OR
THE ECMWF...IS THE ONE TO FOLLOW WITH THIS STORM. THE MAIN
DIFFERENCE COMES WITH THE ORIENTATION OF THE WARM ADVECTION. THE
GFS MAINTAINS A MORE NORTH-NORTHWEST ORIENTATION WITH FAIRLY
STRONG THERMAL ADVECTION INTO AND WEST OF THE WASATCH RANGE
SATURDAY. THE ECMWF IN CONTRAST HAS SOME EASTERLY COMPONENT TO THE
ADVECTION WHICH WOULD FOCUS CLOSER TO THE NEVADA BORDER. THE TRACK
OF THE UPPER LOW...THOUGH FAIRLY SIMILAR IN BOTH MODEL...WOULD
TEND TO SUPPORT THE ECMWF MORE THAN THE GFS. THE CURRENT FORECAST
WOULD STILL MAINTAIN WIDESPREAD AND SUBSTANTIAL PRECIP...THOUGH
QPFS WILL BE SCALED DOWN A BIT ALONG THE URBAN CORRIDOR IN THE
THIS FORECAST PACKAGE.


.LONG TERM (AFTER 06Z MONDAY)...SIMILAR DIFFERENCES EXIST REGARDING
SHORT WAVE EVOLUTION ACROSS THE WESTERN CONUS IN THE LATEST 12Z RUNS
AS THE PREVIOUS FEW. BOTTOM LINE HOWEVER WILL CONTINUE TO FOCUS ON
UNSETTLED WEATHER ACROSS THE AREA AS A MEAN LONG WAVE WILL REMAIN IN
PLACE ACROSS THE WESTERN CONUS THROUGH THE PERIOD.

PRIMARY DIFFERENCE TO BEGIN THE LONG TERM PERIOD REVOLVES AROUND THE
HANDLING OF CUT OFF LOW THAT IS CURRENTLY SPINNING ALONG THE BRITCOL
COASTLINE /AND WILL REMAIN DOING SO FOR THE NEXT FEW DAYS/. THE GFS
CONTINUES TO WANT TO SHEAR A PORTION OF THIS LOBE SOUTHEAST OVER THE
WEEKEND AND INTO OUR AREA EARLY MONDAY MORNING KICKING THE PREVIOUS
UPPER LOW EAST. ECMWF CONTINUES TO TAKE THIS ENERGY IN A MORE LESS
CONSOLIDATED STATE TO OUR WEST...ROTATING IT THROUGH THE BASE OF THE
LONGWAVE. ALTHOUGH BOTH RETAIN FAIRLY WET SOLUTIONS...CONFIDENCE IS
LOW REGARDING PLACEMENT AND POTENTIAL SIGNIFICANCE OF PRECIP ATTM...
BUT FELT IT REASONABLE TO CONTINUE AN INCREASING TREND TO POPS
MONDAY /ESPECIALLY NORTH/.

THEREAFTER MODEL SPREAD ACTUALLY DECREASES THROUGH MIDWEEK. THE
GFS/ECMWF BOTH INDICATE TO SOME REGARD THE PRIMARY BRITCOL LOBE WILL
THEN MEANDER SLOWLY SOUTHEAST AND MERGE WITH A WEAK SOUTHERN BRANCH
SHORT WAVE THAT WILL BE UNDERCUTTING THE MEAN EASTERN PACIFIC RIDGE.
ALTHOUGH HEIGHTS WILL BE ATTEMPTING TO BUILD FROM THE SOUTHEAST AND
SOME WARMING OF TEMPS LOOKS LIKELY...VICINITY OF THESE FEATURES AND
RATHER DEEP MOISTURE IN PLACE NOW LOOKS TO MAINTAIN A GOOD CHANCE OF
FAIRLY WIDESPREAD CONVECTION ACROSS THE NORTHERN HALF OF THE AREA
FOR THE MIDWEEK PERIOD. OPTED TO BUMP POPS BOTH TUE/WED AS SUCH.

&&

.AVIATION...SOUTHWESTERLY WINDS THAT WILL BE GUSTY AT TIMES ARE
EXPECTED TO PREVAIL AT THE KSLC TERMINAL FOR THE NEXT FEW HOURS.
ANOTHER BAND OF IS SHOWERS APPROACHING FROM THE SOUTH AND WILL MOVE
THROUGH THE TERMINAL BY 2330Z BRINGING LIGHT RAIN SHOWERS...AIDING
TO MAINTAIN THIS WIND DIRECTION. UPON PASSAGE OF THESE SHOWERS TO
THE NORTH WINDS ARE EXPECTED TO RETURN TO THE NORTHWEST FOR THE
01Z TO 03Z WINDOW...BEFORE AGAIN RETURNING TO THE SOUTH OVERNIGHT.

&&


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

$$

SHORT TERM...CONGER
LONG TERM/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)





000
FXUS65 KSLC 212218
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
418 PM MDT THU MAY 21 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
MOVE INLAND TONIGHT...THEN TURN NORTHEAST AND SLOWLY TRACK NORTHEAST
THROUGH THE GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z MONDAY)...THE UPPER LOW CENTERED JUST OFF
THE CENTRAL CALIFORNIA COAST THIS AFTERNOON WILL TAKE A TURN TO
THE EAST-SOUTHEAST INTO SOUTHERN CALIFORNIA LATER TONIGHT. FROM
THERE THIS LOW WILL MOVE INTO NORTHWEST ARIZONA FRIDAY NIGHT...
THEN TURN TO THE NORTHEAST AND TRACK SLOWLY THROUGH THE SOUTHERN
AND EASTERN GREAT BASIN THIS WEEKEND.

AHEAD OF THIS UPPER LOW AT LEAST TWO OR THREE VORTICITY LOBE WILL
EJECT OUT OF THE PARENT LOW AND TRACK NORTH ACROSS UTAH TONIGHT
THROUGH EARLY FRIDAY. THIS DYNAMIC SUPPORT FOR LIFT WORKING WITH
THE FAIRLY MOIST AND UNSTABLE AIR MASS ALREADY IN PLACE WILL
PRODUCE PERIODIC SHOWERS/THUNDERSTORMS. GOOD UPPER DIVERGENCE WILL
ALSO SUPPORT DEEP CONVECTION CAPABLE OF PRODUCING HEAVY
RAIN/SMALL HAIL WITH THE STRONG CONVECTIVE ELEMENTS.

THE SLOW NORTHEAST PROGRESSION OF THE UPPER LOW THROUGH SOUTHERN
AND EASTERN UTAH WILL LEAD TO A PROLONGED PERIOD OF VALLEY RAIN
AND HIGH ELEVATION SNOW THIS WEEKEND. SOLID SYNOPTIC-SCALE LIFT
AND MORE THE ADEQUATE MOISTURE SHOULD HAVE LITTLE TROUBLE GENERATE
WIDESPREAD PRECIPITATION BEGINNING LATE FRIDAY NIGHT AND
CONTINUING INTO AT LEAST SATURDAY EVENING.

WILL CONCENTRATE THE HEAVIEST PRECIP IN THE AREAS NORTH AND WEST
OF THE UPPER LOW WHERE DEEP LAYER AND MOIST WARM ADVECTION WRAP
AROUND EXISTS. THESE AREAS OF THERMALLY-DRIVEN LIFT HAVE BEEN
RATHER PROLIFIC IN THE AMOUNT OF PRECIP GENERATED IN RECENT
STORMS...AND SEE NO GOOD REASON TO DEVIATE FROM THIS THINKING AT
THIS TIME. QUESTION RIGHT NOW IS WHICH MODEL...EITHER THE GFS OR
THE ECMWF...IS THE ONE TO FOLLOW WITH THIS STORM. THE MAIN
DIFFERENCE COMES WITH THE ORIENTATION OF THE WARM ADVECTION. THE
GFS MAINTAINS A MORE NORTH-NORTHWEST ORIENTATION WITH FAIRLY
STRONG THERMAL ADVECTION INTO AND WEST OF THE WASATCH RANGE
SATURDAY. THE ECMWF IN CONTRAST HAS SOME EASTERLY COMPONENT TO THE
ADVECTION WHICH WOULD FOCUS CLOSER TO THE NEVADA BORDER. THE TRACK
OF THE UPPER LOW...THOUGH FAIRLY SIMILAR IN BOTH MODEL...WOULD
TEND TO SUPPORT THE ECMWF MORE THAN THE GFS. THE CURRENT FORECAST
WOULD STILL MAINTAIN WIDESPREAD AND SUBSTANTIAL PRECIP...THOUGH
QPFS WILL BE SCALED DOWN A BIT ALONG THE URBAN CORRIDOR IN THE
THIS FORECAST PACKAGE.


.LONG TERM (AFTER 06Z MONDAY)...SIMILAR DIFFERENCES EXIST REGARDING
SHORT WAVE EVOLUTION ACROSS THE WESTERN CONUS IN THE LATEST 12Z RUNS
AS THE PREVIOUS FEW. BOTTOM LINE HOWEVER WILL CONTINUE TO FOCUS ON
UNSETTLED WEATHER ACROSS THE AREA AS A MEAN LONG WAVE WILL REMAIN IN
PLACE ACROSS THE WESTERN CONUS THROUGH THE PERIOD.

PRIMARY DIFFERENCE TO BEGIN THE LONG TERM PERIOD REVOLVES AROUND THE
HANDLING OF CUT OFF LOW THAT IS CURRENTLY SPINNING ALONG THE BRITCOL
COASTLINE /AND WILL REMAIN DOING SO FOR THE NEXT FEW DAYS/. THE GFS
CONTINUES TO WANT TO SHEAR A PORTION OF THIS LOBE SOUTHEAST OVER THE
WEEKEND AND INTO OUR AREA EARLY MONDAY MORNING KICKING THE PREVIOUS
UPPER LOW EAST. ECMWF CONTINUES TO TAKE THIS ENERGY IN A MORE LESS
CONSOLIDATED STATE TO OUR WEST...ROTATING IT THROUGH THE BASE OF THE
LONGWAVE. ALTHOUGH BOTH RETAIN FAIRLY WET SOLUTIONS...CONFIDENCE IS
LOW REGARDING PLACEMENT AND POTENTIAL SIGNIFICANCE OF PRECIP ATTM...
BUT FELT IT REASONABLE TO CONTINUE AN INCREASING TREND TO POPS
MONDAY /ESPECIALLY NORTH/.

THEREAFTER MODEL SPREAD ACTUALLY DECREASES THROUGH MIDWEEK. THE
GFS/ECMWF BOTH INDICATE TO SOME REGARD THE PRIMARY BRITCOL LOBE WILL
THEN MEANDER SLOWLY SOUTHEAST AND MERGE WITH A WEAK SOUTHERN BRANCH
SHORT WAVE THAT WILL BE UNDERCUTTING THE MEAN EASTERN PACIFIC RIDGE.
ALTHOUGH HEIGHTS WILL BE ATTEMPTING TO BUILD FROM THE SOUTHEAST AND
SOME WARMING OF TEMPS LOOKS LIKELY...VICINITY OF THESE FEATURES AND
RATHER DEEP MOISTURE IN PLACE NOW LOOKS TO MAINTAIN A GOOD CHANCE OF
FAIRLY WIDESPREAD CONVECTION ACROSS THE NORTHERN HALF OF THE AREA
FOR THE MIDWEEK PERIOD. OPTED TO BUMP POPS BOTH TUE/WED AS SUCH.

&&

.AVIATION...SOUTHWESTERLY WINDS THAT WILL BE GUSTY AT TIMES ARE
EXPECTED TO PREVAIL AT THE KSLC TERMINAL FOR THE NEXT FEW HOURS.
ANOTHER BAND OF IS SHOWERS APPROACHING FROM THE SOUTH AND WILL MOVE
THROUGH THE TERMINAL BY 2330Z BRINGING LIGHT RAIN SHOWERS...AIDING
TO MAINTAIN THIS WIND DIRECTION. UPON PASSAGE OF THESE SHOWERS TO
THE NORTH WINDS ARE EXPECTED TO RETURN TO THE NORTHWEST FOR THE
01Z TO 03Z WINDOW...BEFORE AGAIN RETURNING TO THE SOUTH OVERNIGHT.

&&


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

$$

SHORT TERM...CONGER
LONG TERM/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)




000
FXUS65 KSLC 212218
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
418 PM MDT THU MAY 21 2015

.SYNOPSIS...THE LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
MOVE INLAND TONIGHT...THEN TURN NORTHEAST AND SLOWLY TRACK NORTHEAST
THROUGH THE GREAT BASIN THIS WEEKEND.

&&

.SHORT TERM (THROUGH 06Z MONDAY)...THE UPPER LOW CENTERED JUST OFF
THE CENTRAL CALIFORNIA COAST THIS AFTERNOON WILL TAKE A TURN TO
THE EAST-SOUTHEAST INTO SOUTHERN CALIFORNIA LATER TONIGHT. FROM
THERE THIS LOW WILL MOVE INTO NORTHWEST ARIZONA FRIDAY NIGHT...
THEN TURN TO THE NORTHEAST AND TRACK SLOWLY THROUGH THE SOUTHERN
AND EASTERN GREAT BASIN THIS WEEKEND.

AHEAD OF THIS UPPER LOW AT LEAST TWO OR THREE VORTICITY LOBE WILL
EJECT OUT OF THE PARENT LOW AND TRACK NORTH ACROSS UTAH TONIGHT
THROUGH EARLY FRIDAY. THIS DYNAMIC SUPPORT FOR LIFT WORKING WITH
THE FAIRLY MOIST AND UNSTABLE AIR MASS ALREADY IN PLACE WILL
PRODUCE PERIODIC SHOWERS/THUNDERSTORMS. GOOD UPPER DIVERGENCE WILL
ALSO SUPPORT DEEP CONVECTION CAPABLE OF PRODUCING HEAVY
RAIN/SMALL HAIL WITH THE STRONG CONVECTIVE ELEMENTS.

THE SLOW NORTHEAST PROGRESSION OF THE UPPER LOW THROUGH SOUTHERN
AND EASTERN UTAH WILL LEAD TO A PROLONGED PERIOD OF VALLEY RAIN
AND HIGH ELEVATION SNOW THIS WEEKEND. SOLID SYNOPTIC-SCALE LIFT
AND MORE THE ADEQUATE MOISTURE SHOULD HAVE LITTLE TROUBLE GENERATE
WIDESPREAD PRECIPITATION BEGINNING LATE FRIDAY NIGHT AND
CONTINUING INTO AT LEAST SATURDAY EVENING.

WILL CONCENTRATE THE HEAVIEST PRECIP IN THE AREAS NORTH AND WEST
OF THE UPPER LOW WHERE DEEP LAYER AND MOIST WARM ADVECTION WRAP
AROUND EXISTS. THESE AREAS OF THERMALLY-DRIVEN LIFT HAVE BEEN
RATHER PROLIFIC IN THE AMOUNT OF PRECIP GENERATED IN RECENT
STORMS...AND SEE NO GOOD REASON TO DEVIATE FROM THIS THINKING AT
THIS TIME. QUESTION RIGHT NOW IS WHICH MODEL...EITHER THE GFS OR
THE ECMWF...IS THE ONE TO FOLLOW WITH THIS STORM. THE MAIN
DIFFERENCE COMES WITH THE ORIENTATION OF THE WARM ADVECTION. THE
GFS MAINTAINS A MORE NORTH-NORTHWEST ORIENTATION WITH FAIRLY
STRONG THERMAL ADVECTION INTO AND WEST OF THE WASATCH RANGE
SATURDAY. THE ECMWF IN CONTRAST HAS SOME EASTERLY COMPONENT TO THE
ADVECTION WHICH WOULD FOCUS CLOSER TO THE NEVADA BORDER. THE TRACK
OF THE UPPER LOW...THOUGH FAIRLY SIMILAR IN BOTH MODEL...WOULD
TEND TO SUPPORT THE ECMWF MORE THAN THE GFS. THE CURRENT FORECAST
WOULD STILL MAINTAIN WIDESPREAD AND SUBSTANTIAL PRECIP...THOUGH
QPFS WILL BE SCALED DOWN A BIT ALONG THE URBAN CORRIDOR IN THE
THIS FORECAST PACKAGE.


.LONG TERM (AFTER 06Z MONDAY)...SIMILAR DIFFERENCES EXIST REGARDING
SHORT WAVE EVOLUTION ACROSS THE WESTERN CONUS IN THE LATEST 12Z RUNS
AS THE PREVIOUS FEW. BOTTOM LINE HOWEVER WILL CONTINUE TO FOCUS ON
UNSETTLED WEATHER ACROSS THE AREA AS A MEAN LONG WAVE WILL REMAIN IN
PLACE ACROSS THE WESTERN CONUS THROUGH THE PERIOD.

PRIMARY DIFFERENCE TO BEGIN THE LONG TERM PERIOD REVOLVES AROUND THE
HANDLING OF CUT OFF LOW THAT IS CURRENTLY SPINNING ALONG THE BRITCOL
COASTLINE /AND WILL REMAIN DOING SO FOR THE NEXT FEW DAYS/. THE GFS
CONTINUES TO WANT TO SHEAR A PORTION OF THIS LOBE SOUTHEAST OVER THE
WEEKEND AND INTO OUR AREA EARLY MONDAY MORNING KICKING THE PREVIOUS
UPPER LOW EAST. ECMWF CONTINUES TO TAKE THIS ENERGY IN A MORE LESS
CONSOLIDATED STATE TO OUR WEST...ROTATING IT THROUGH THE BASE OF THE
LONGWAVE. ALTHOUGH BOTH RETAIN FAIRLY WET SOLUTIONS...CONFIDENCE IS
LOW REGARDING PLACEMENT AND POTENTIAL SIGNIFICANCE OF PRECIP ATTM...
BUT FELT IT REASONABLE TO CONTINUE AN INCREASING TREND TO POPS
MONDAY /ESPECIALLY NORTH/.

THEREAFTER MODEL SPREAD ACTUALLY DECREASES THROUGH MIDWEEK. THE
GFS/ECMWF BOTH INDICATE TO SOME REGARD THE PRIMARY BRITCOL LOBE WILL
THEN MEANDER SLOWLY SOUTHEAST AND MERGE WITH A WEAK SOUTHERN BRANCH
SHORT WAVE THAT WILL BE UNDERCUTTING THE MEAN EASTERN PACIFIC RIDGE.
ALTHOUGH HEIGHTS WILL BE ATTEMPTING TO BUILD FROM THE SOUTHEAST AND
SOME WARMING OF TEMPS LOOKS LIKELY...VICINITY OF THESE FEATURES AND
RATHER DEEP MOISTURE IN PLACE NOW LOOKS TO MAINTAIN A GOOD CHANCE OF
FAIRLY WIDESPREAD CONVECTION ACROSS THE NORTHERN HALF OF THE AREA
FOR THE MIDWEEK PERIOD. OPTED TO BUMP POPS BOTH TUE/WED AS SUCH.

&&

.AVIATION...SOUTHWESTERLY WINDS THAT WILL BE GUSTY AT TIMES ARE
EXPECTED TO PREVAIL AT THE KSLC TERMINAL FOR THE NEXT FEW HOURS.
ANOTHER BAND OF IS SHOWERS APPROACHING FROM THE SOUTH AND WILL MOVE
THROUGH THE TERMINAL BY 2330Z BRINGING LIGHT RAIN SHOWERS...AIDING
TO MAINTAIN THIS WIND DIRECTION. UPON PASSAGE OF THESE SHOWERS TO
THE NORTH WINDS ARE EXPECTED TO RETURN TO THE NORTHWEST FOR THE
01Z TO 03Z WINDOW...BEFORE AGAIN RETURNING TO THE SOUTH OVERNIGHT.

&&


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

$$

SHORT TERM...CONGER
LONG TERM/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)





000
FXUS65 KSLC 211623
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1023 AM MDT THU MAY 21 2015

.SYNOPSIS...THE UPPER LEVEL LOW PRESSURE SYSTEM OFF THE CALIFORNIA
COAST WILL SEND A SERIES OF WEATHER DISTURBANCES NORTH ACROSS THE
GREAT BASIN THROUGH EARLY FRIDAY. THE LOW PRESSURE SYSTEM WILL
SLOWLY CROSS THE GREAT BASIN LATE FRIDAY THROUGH THE WEEKEND.

&&

.DISCUSSION...THE MEAN UPPER LOW CURRENTLY POSITIONED OFF THE
CALIFORNIA COAST WILL CONTINUE TO EJECT VORTICITY LOBE NORTH
ACROSS THE GREAT BASIN THROUGH EARLY FRIDAY. ONE SUCH LOBE NEAR
THE UTAH/ARIZONA BORDER WILL CONTINUE NORTH INTO NORTHERN UTAH BY
LATE THIS AFTERNOON. THIS DYNAMIC FEATURE WILL FIND ADEQUATE
MOISTURE AS IT PASSES THROUGH DURING PEAK HEATING TIME. SCATTERED
SHOWERS/STORMS LOOK TO BE A GOOD BET FOR THE NORTH...WITH LESSER
AREAL COVERAGE CENTRAL AND SOUTH DUE TO SUBSIDENCE TRAILING THE
VORTICITY LOBE.

SUBSEQUENT WEAK DYNAMIC FEATURES TONIGHT/EARLY FRIDAY WILL
MAINTAIN A THREAT OF SHOWERS/STORMS AHEAD OF THE ADVANCING
COASTAL CALIFORNIA LOW. PRECIP WILL BECOME MORE WIDESPREAD
BEGINNING LATE FRIDAY AS THE UPPER LOW TURNS NORTHEAST AND TRACKS
THROUGH THE SOUTHERN/EASTERN GREAT BASIN. GOOD SYNOPTIC-SCALE LIFT
AND MOISTURE THROUGH SATURDAY NIGHT WILL MAINTAIN VALLEY RAIN AND
MOUNTAIN SNOW ACROSS MUCH OF THE FORECAST AREA. PRECIP WILL LIKELY
DIMINISH A BIT BY EARLY SUNDAY...THEN EXPAND ONCE AGAIN AS
ANOTHER VORTICITY LOBE ROTATES SOUTH ALONG THE BACK SIDE OF THE
EXITING UPPER LOW. A SHORTWAVE RIDGE ON MONDAY WILL LIMIT THE
THREAT FOR CONVECTION...WITH THIS ACTIVITY CONFINED MAINLY TO THE
NEAR/OVER THE HIGHER TERRAIN DURING THE LATE MORNING THROUGH EARLY
EVENING HOURS.

NO UPDATES PLANNED TO THE SHORT TERM FORECAST AT THIS TIME.

&&

.AVIATION...WARMER TEMPS AND ADEQUATE MOISTURE WILL LEAD TO
ANOTHER DAY OF SHOWERS/THUNDERSTORMS BUILDING OVER THE SURROUNDING
HIGHER TERRAIN THEN DRIFTING INTO THE VALLEY DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. FIRST IMPACTS WITH CONVECTION
WILL LIKELY HOLD OFF UNTIL AFTER 21Z...WITH WINDS AND BRIEF HEAVY
RAIN THE MAIN ISSUES OVER AND SOUTH OF THE TERMINAL THROUGH AROUND
03Z-04Z.

WINDS THROUGH MID-AFTERNOON WILL BE LIGHT OUT OF THE NORTH-
NORTHWEST...WITH CONVECTION DRIVING SOUTH WINDS BACK TO THE
TERMINAL DURING THE LATE AFTERNOON/EVENING HOURS.

&&

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

$$

CONGER

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)




000
FXUS65 KSLC 211623
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1023 AM MDT THU MAY 21 2015

.SYNOPSIS...THE UPPER LEVEL LOW PRESSURE SYSTEM OFF THE CALIFORNIA
COAST WILL SEND A SERIES OF WEATHER DISTURBANCES NORTH ACROSS THE
GREAT BASIN THROUGH EARLY FRIDAY. THE LOW PRESSURE SYSTEM WILL
SLOWLY CROSS THE GREAT BASIN LATE FRIDAY THROUGH THE WEEKEND.

&&

.DISCUSSION...THE MEAN UPPER LOW CURRENTLY POSITIONED OFF THE
CALIFORNIA COAST WILL CONTINUE TO EJECT VORTICITY LOBE NORTH
ACROSS THE GREAT BASIN THROUGH EARLY FRIDAY. ONE SUCH LOBE NEAR
THE UTAH/ARIZONA BORDER WILL CONTINUE NORTH INTO NORTHERN UTAH BY
LATE THIS AFTERNOON. THIS DYNAMIC FEATURE WILL FIND ADEQUATE
MOISTURE AS IT PASSES THROUGH DURING PEAK HEATING TIME. SCATTERED
SHOWERS/STORMS LOOK TO BE A GOOD BET FOR THE NORTH...WITH LESSER
AREAL COVERAGE CENTRAL AND SOUTH DUE TO SUBSIDENCE TRAILING THE
VORTICITY LOBE.

SUBSEQUENT WEAK DYNAMIC FEATURES TONIGHT/EARLY FRIDAY WILL
MAINTAIN A THREAT OF SHOWERS/STORMS AHEAD OF THE ADVANCING
COASTAL CALIFORNIA LOW. PRECIP WILL BECOME MORE WIDESPREAD
BEGINNING LATE FRIDAY AS THE UPPER LOW TURNS NORTHEAST AND TRACKS
THROUGH THE SOUTHERN/EASTERN GREAT BASIN. GOOD SYNOPTIC-SCALE LIFT
AND MOISTURE THROUGH SATURDAY NIGHT WILL MAINTAIN VALLEY RAIN AND
MOUNTAIN SNOW ACROSS MUCH OF THE FORECAST AREA. PRECIP WILL LIKELY
DIMINISH A BIT BY EARLY SUNDAY...THEN EXPAND ONCE AGAIN AS
ANOTHER VORTICITY LOBE ROTATES SOUTH ALONG THE BACK SIDE OF THE
EXITING UPPER LOW. A SHORTWAVE RIDGE ON MONDAY WILL LIMIT THE
THREAT FOR CONVECTION...WITH THIS ACTIVITY CONFINED MAINLY TO THE
NEAR/OVER THE HIGHER TERRAIN DURING THE LATE MORNING THROUGH EARLY
EVENING HOURS.

NO UPDATES PLANNED TO THE SHORT TERM FORECAST AT THIS TIME.

&&

.AVIATION...WARMER TEMPS AND ADEQUATE MOISTURE WILL LEAD TO
ANOTHER DAY OF SHOWERS/THUNDERSTORMS BUILDING OVER THE SURROUNDING
HIGHER TERRAIN THEN DRIFTING INTO THE VALLEY DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. FIRST IMPACTS WITH CONVECTION
WILL LIKELY HOLD OFF UNTIL AFTER 21Z...WITH WINDS AND BRIEF HEAVY
RAIN THE MAIN ISSUES OVER AND SOUTH OF THE TERMINAL THROUGH AROUND
03Z-04Z.

WINDS THROUGH MID-AFTERNOON WILL BE LIGHT OUT OF THE NORTH-
NORTHWEST...WITH CONVECTION DRIVING SOUTH WINDS BACK TO THE
TERMINAL DURING THE LATE AFTERNOON/EVENING HOURS.

&&

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

$$

CONGER

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)





000
FXUS65 KSLC 211623
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1023 AM MDT THU MAY 21 2015

.SYNOPSIS...THE UPPER LEVEL LOW PRESSURE SYSTEM OFF THE CALIFORNIA
COAST WILL SEND A SERIES OF WEATHER DISTURBANCES NORTH ACROSS THE
GREAT BASIN THROUGH EARLY FRIDAY. THE LOW PRESSURE SYSTEM WILL
SLOWLY CROSS THE GREAT BASIN LATE FRIDAY THROUGH THE WEEKEND.

&&

.DISCUSSION...THE MEAN UPPER LOW CURRENTLY POSITIONED OFF THE
CALIFORNIA COAST WILL CONTINUE TO EJECT VORTICITY LOBE NORTH
ACROSS THE GREAT BASIN THROUGH EARLY FRIDAY. ONE SUCH LOBE NEAR
THE UTAH/ARIZONA BORDER WILL CONTINUE NORTH INTO NORTHERN UTAH BY
LATE THIS AFTERNOON. THIS DYNAMIC FEATURE WILL FIND ADEQUATE
MOISTURE AS IT PASSES THROUGH DURING PEAK HEATING TIME. SCATTERED
SHOWERS/STORMS LOOK TO BE A GOOD BET FOR THE NORTH...WITH LESSER
AREAL COVERAGE CENTRAL AND SOUTH DUE TO SUBSIDENCE TRAILING THE
VORTICITY LOBE.

SUBSEQUENT WEAK DYNAMIC FEATURES TONIGHT/EARLY FRIDAY WILL
MAINTAIN A THREAT OF SHOWERS/STORMS AHEAD OF THE ADVANCING
COASTAL CALIFORNIA LOW. PRECIP WILL BECOME MORE WIDESPREAD
BEGINNING LATE FRIDAY AS THE UPPER LOW TURNS NORTHEAST AND TRACKS
THROUGH THE SOUTHERN/EASTERN GREAT BASIN. GOOD SYNOPTIC-SCALE LIFT
AND MOISTURE THROUGH SATURDAY NIGHT WILL MAINTAIN VALLEY RAIN AND
MOUNTAIN SNOW ACROSS MUCH OF THE FORECAST AREA. PRECIP WILL LIKELY
DIMINISH A BIT BY EARLY SUNDAY...THEN EXPAND ONCE AGAIN AS
ANOTHER VORTICITY LOBE ROTATES SOUTH ALONG THE BACK SIDE OF THE
EXITING UPPER LOW. A SHORTWAVE RIDGE ON MONDAY WILL LIMIT THE
THREAT FOR CONVECTION...WITH THIS ACTIVITY CONFINED MAINLY TO THE
NEAR/OVER THE HIGHER TERRAIN DURING THE LATE MORNING THROUGH EARLY
EVENING HOURS.

NO UPDATES PLANNED TO THE SHORT TERM FORECAST AT THIS TIME.

&&

.AVIATION...WARMER TEMPS AND ADEQUATE MOISTURE WILL LEAD TO
ANOTHER DAY OF SHOWERS/THUNDERSTORMS BUILDING OVER THE SURROUNDING
HIGHER TERRAIN THEN DRIFTING INTO THE VALLEY DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. FIRST IMPACTS WITH CONVECTION
WILL LIKELY HOLD OFF UNTIL AFTER 21Z...WITH WINDS AND BRIEF HEAVY
RAIN THE MAIN ISSUES OVER AND SOUTH OF THE TERMINAL THROUGH AROUND
03Z-04Z.

WINDS THROUGH MID-AFTERNOON WILL BE LIGHT OUT OF THE NORTH-
NORTHWEST...WITH CONVECTION DRIVING SOUTH WINDS BACK TO THE
TERMINAL DURING THE LATE AFTERNOON/EVENING HOURS.

&&

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

$$

CONGER

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)





000
FXUS65 KSLC 211021
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
421 AM MDT THU MAY 21 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. THE NEXT STORM WILL CROSS THE GREAT
BASIN FRIDAY THROUGH TUESDAY.

&&

.SHORT TERM (THROUGH 12Z SUNDAY)...
WATER VAPOR LOOP SHOWS A CLOSED LOW OFF THE CALIFORNIA
COAST...WITH RIDGING SHIFTING INTO THE CENTRAL ROCKIES. AMDAR
400-250MB WIND OBSERVATIONS SHOW A 75-115KT CYCLONIC JET FROM THE
EASTERN PACIFIC INTO THE FOUR CORNERS. GOES/GPS/RAP/00Z SLC RAOB
INDICATE THE PRECIPITABLE WATER VALUE RANGES BETWEEN 0.25"-0.50"
MOUNTAINS...TO 0.45"-0.75" ACROSS THE VALLEYS.

A LULL IN ACTIVITY WILL OCCUR THROUGH MID MORNING...AS A PASSING
WAVE LIFTS NORTH INTO IDAHO LEAVING SUBSIDENCE IN ITS WAKE.
CONVECTION WILL GET GOING ALONG THE MOUNTAINS DURING THE MID TO LATE
MORNING HOURS. ANOTHER DISTURBANCE WILL LIFT OUT OF THE BASE OF THE
TROUGH OVER UTAH FROM SOUTH TO NORTH TODAY. THIS FEATURE SHOULD
ORGANIZE CONVECTION LEADING TO AN INCREASE IN COVERAGE. OTHER
SUPPORT FOR CONVECTION INCLUDE INCREASING DIFFLUENCE ALOFT AND THE
UPPER LEVEL JET NOISING INTO EASTERN UTAH.

SINCE LOW LEVELS HAVE DRIED OUT AS FORECAST...GUSTY DRY MICROBURST
WINDS WILL BECOME MORE LIKELY WITH CONVECTION TODAY. OTHER THREATS
INCLUDE CLOUD TO GROUND LIGHTNING...SMALL HAIL...AND A BRIEF HEAVY
RAIN.

FRIDAY AN AREA OF DEFORMATION NORTH OF THE CLOSED LOW WILL BEGIN TO
IMPACT THE STATE...LEADING TO AN INCREASE IN CONVECTIVE COVERAGE. THE
BEST COVERAGE OF RAIN IS LIKELY SOMETIME SATURDAY OR SATURDAY NIGHT
WHEN WRAP-AROUND PRECIPITATION DUE TO MID LEVEL WARM ADVECTION
ARRIVES FROM THE NORTHEAST. BY THIS TIME GLOBAL MODELS ARE BEGINNING
TO DIVERGE ON TIMING/PROGRESSION OF LARGE SCALE
FEATURES...CONFIDENCE AT THIS TIME. HAVE CUT POPS BACK TO LIKELY IN
THE VALLEYS AS ITS HARD TO PIN DOWN A PERIOD OR TWO FOR THE MOST
WIDESPREAD ACTIVITY GIVEN MODEL SPREAD.

.LONG TERM (AFTER 12Z SUNDAY)...
ALTHOUGH THERE IS A BASIC TROUGH OVER THE GREAT BASIN SUNDAY INTO
MONDAY...THE DETAILS ARE QUITE DIFFERENT BETWEEN MODELS WITH THE
GFS SHOWING MULTIPLE CIRCULATIONS WHILE THE EC HAS ONE
CONSOLIDATED SYSTEM. ALTHOUGH THE DETAILS ARE YET TO SHAKE OUT ON
WHERE THE MOST LIKELY AND HEAVIEST PRECIP WILL OCCUR IT SEEMED
REASONABLE TO BOOST POPS DUE TO THE TROUGH OVERHEAD AND THE
PRECIPITABLE WATER FORECAST TO BE AT THEIR HIGHEST LEVELS DURING
THE SEVEN PERIOD NEAR 0.60-0.75 OF AN INCH.

THE PW AMOUNTS GRADUALLY LOWER THROUGH THE WEEK AS THE TROUGH
WEAKENS AND A RIDGE BUILDS IN FROM THE SOUTHEAST. DUE TO THE STILL
RELATIVELY MOIST AIR MASS HAD TO KEEP SCATTERED SHOWERS BY DAY AND
ISOLATED BY NIGHT TUESDAY BUT TAILED OFF THE PROBABILITY WEDNESDAY
INTO THURSDAY. THE FORECAST WAS MAINLY BASED ON THE GFS BUT SOME
CONSIDERATION WAS GIVEN TO THE EC. THEREFORE THE CONTINUATION OF
SHOWERS INTO THURSDAY AS THE EC SHOWS A FEATURE MOVING THROUGH UTAH
WHILE THE GFS KEEPS THE TROUGH OVER THE WESTERN GREAT BASIN INTO
CALIFORNIA AREA.

DUE TO RIDGE MOVING IN...THE 700 MB TEMPS ACTUALLY WARM TO LEVELS OF
PLUS 8-10 ON WEDNESDAY AND 8-12 ON THURSDAY ACCORDING TO THE GFS
WHILE THE EC IS SEVERAL DEGREES COOLER DUE TO THE FEATURE MOVING
THROUGH. HAVE LEANED TOWARDS THE GFS SOLUTION ONCE AGAIN AND
THEREFORE RAISED TEMPERATURES IN THE EXTENDED BY A FEW DEGREES.

&&

.AVIATION...A LULL IN CONVECTION IS EXPECTED AT THE SLC TERMINAL
THROUGH AT LEAST 19-20Z. THEN STORMS ARE EXPECTED TO MOVE THROUGH IN
THE 20Z-03Z PERIOD WITH BRIEF HEAVY RAIN...GUSTY WINDS TO OVER 30
MPH...AND CIGS AOB 5000FT AGL DURING STORM ACTIVITY AND VSBY DOWN TO
MVFR LEVELS ARE ALL POSSIBLE. WINDS WILL BE SOUTHERLY THROUGHOUT THE
TAF PERIOD BUT WILL BECOME ERRATIC DURING CONVECTION.

&&

.FIRE WEATHER...TODAY WILL BE THE WARMEST AND DRIEST DAY ACROSS THE
REGION THROUGH THE HOLIDAY WEEKEND. STILL...THERE IS ENOUGH MOISTURE
IN PLACE AHEAD OF THE NEXT STORM SYSTEM TO FOSTER THE DEVELOPMENT OF
SCATTERED SHOWERS AND THUNDERSTORMS DURING THE MID MORNING THROUGH
THE EVENING HOURS. CLOUD TO GROUND LIGHTNING...GUSTY/ERRATIC
WINDS...A BRIEF HEAVY DOWNPOUR...AND SMALL HAIL ARE ALL POSSIBLE
WITH THE STRONGER ACTIVITY.

THE NEXT STORM SYSTEM ARRIVES TOMORROW AND PERSISTS THROUGH THE
HOLIDAY WEEKEND. SHOWERS AND THUNDERSTORMS WILL GROW MORE NUMEROUS
ACROSS THE REGION...WITH THE GREATEST COVERAGE IN ACTIVITY EXPECTED
SATURDAY. TEMPERATURES WILL TREND COOLER AND HUMIDITY WILL TREND
HIGHER. SNOW LEVELS WILL BE BETWEEN 8-9KFT...FALLING TO 7KFT UNDER
THE HEAVIEST ACTIVITY.

&&

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

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...STRUTHWOLF

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)





000
FXUS65 KSLC 211021
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
421 AM MDT THU MAY 21 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. THE NEXT STORM WILL CROSS THE GREAT
BASIN FRIDAY THROUGH TUESDAY.

&&

.SHORT TERM (THROUGH 12Z SUNDAY)...
WATER VAPOR LOOP SHOWS A CLOSED LOW OFF THE CALIFORNIA
COAST...WITH RIDGING SHIFTING INTO THE CENTRAL ROCKIES. AMDAR
400-250MB WIND OBSERVATIONS SHOW A 75-115KT CYCLONIC JET FROM THE
EASTERN PACIFIC INTO THE FOUR CORNERS. GOES/GPS/RAP/00Z SLC RAOB
INDICATE THE PRECIPITABLE WATER VALUE RANGES BETWEEN 0.25"-0.50"
MOUNTAINS...TO 0.45"-0.75" ACROSS THE VALLEYS.

A LULL IN ACTIVITY WILL OCCUR THROUGH MID MORNING...AS A PASSING
WAVE LIFTS NORTH INTO IDAHO LEAVING SUBSIDENCE IN ITS WAKE.
CONVECTION WILL GET GOING ALONG THE MOUNTAINS DURING THE MID TO LATE
MORNING HOURS. ANOTHER DISTURBANCE WILL LIFT OUT OF THE BASE OF THE
TROUGH OVER UTAH FROM SOUTH TO NORTH TODAY. THIS FEATURE SHOULD
ORGANIZE CONVECTION LEADING TO AN INCREASE IN COVERAGE. OTHER
SUPPORT FOR CONVECTION INCLUDE INCREASING DIFFLUENCE ALOFT AND THE
UPPER LEVEL JET NOISING INTO EASTERN UTAH.

SINCE LOW LEVELS HAVE DRIED OUT AS FORECAST...GUSTY DRY MICROBURST
WINDS WILL BECOME MORE LIKELY WITH CONVECTION TODAY. OTHER THREATS
INCLUDE CLOUD TO GROUND LIGHTNING...SMALL HAIL...AND A BRIEF HEAVY
RAIN.

FRIDAY AN AREA OF DEFORMATION NORTH OF THE CLOSED LOW WILL BEGIN TO
IMPACT THE STATE...LEADING TO AN INCREASE IN CONVECTIVE COVERAGE. THE
BEST COVERAGE OF RAIN IS LIKELY SOMETIME SATURDAY OR SATURDAY NIGHT
WHEN WRAP-AROUND PRECIPITATION DUE TO MID LEVEL WARM ADVECTION
ARRIVES FROM THE NORTHEAST. BY THIS TIME GLOBAL MODELS ARE BEGINNING
TO DIVERGE ON TIMING/PROGRESSION OF LARGE SCALE
FEATURES...CONFIDENCE AT THIS TIME. HAVE CUT POPS BACK TO LIKELY IN
THE VALLEYS AS ITS HARD TO PIN DOWN A PERIOD OR TWO FOR THE MOST
WIDESPREAD ACTIVITY GIVEN MODEL SPREAD.

.LONG TERM (AFTER 12Z SUNDAY)...
ALTHOUGH THERE IS A BASIC TROUGH OVER THE GREAT BASIN SUNDAY INTO
MONDAY...THE DETAILS ARE QUITE DIFFERENT BETWEEN MODELS WITH THE
GFS SHOWING MULTIPLE CIRCULATIONS WHILE THE EC HAS ONE
CONSOLIDATED SYSTEM. ALTHOUGH THE DETAILS ARE YET TO SHAKE OUT ON
WHERE THE MOST LIKELY AND HEAVIEST PRECIP WILL OCCUR IT SEEMED
REASONABLE TO BOOST POPS DUE TO THE TROUGH OVERHEAD AND THE
PRECIPITABLE WATER FORECAST TO BE AT THEIR HIGHEST LEVELS DURING
THE SEVEN PERIOD NEAR 0.60-0.75 OF AN INCH.

THE PW AMOUNTS GRADUALLY LOWER THROUGH THE WEEK AS THE TROUGH
WEAKENS AND A RIDGE BUILDS IN FROM THE SOUTHEAST. DUE TO THE STILL
RELATIVELY MOIST AIR MASS HAD TO KEEP SCATTERED SHOWERS BY DAY AND
ISOLATED BY NIGHT TUESDAY BUT TAILED OFF THE PROBABILITY WEDNESDAY
INTO THURSDAY. THE FORECAST WAS MAINLY BASED ON THE GFS BUT SOME
CONSIDERATION WAS GIVEN TO THE EC. THEREFORE THE CONTINUATION OF
SHOWERS INTO THURSDAY AS THE EC SHOWS A FEATURE MOVING THROUGH UTAH
WHILE THE GFS KEEPS THE TROUGH OVER THE WESTERN GREAT BASIN INTO
CALIFORNIA AREA.

DUE TO RIDGE MOVING IN...THE 700 MB TEMPS ACTUALLY WARM TO LEVELS OF
PLUS 8-10 ON WEDNESDAY AND 8-12 ON THURSDAY ACCORDING TO THE GFS
WHILE THE EC IS SEVERAL DEGREES COOLER DUE TO THE FEATURE MOVING
THROUGH. HAVE LEANED TOWARDS THE GFS SOLUTION ONCE AGAIN AND
THEREFORE RAISED TEMPERATURES IN THE EXTENDED BY A FEW DEGREES.

&&

.AVIATION...A LULL IN CONVECTION IS EXPECTED AT THE SLC TERMINAL
THROUGH AT LEAST 19-20Z. THEN STORMS ARE EXPECTED TO MOVE THROUGH IN
THE 20Z-03Z PERIOD WITH BRIEF HEAVY RAIN...GUSTY WINDS TO OVER 30
MPH...AND CIGS AOB 5000FT AGL DURING STORM ACTIVITY AND VSBY DOWN TO
MVFR LEVELS ARE ALL POSSIBLE. WINDS WILL BE SOUTHERLY THROUGHOUT THE
TAF PERIOD BUT WILL BECOME ERRATIC DURING CONVECTION.

&&

.FIRE WEATHER...TODAY WILL BE THE WARMEST AND DRIEST DAY ACROSS THE
REGION THROUGH THE HOLIDAY WEEKEND. STILL...THERE IS ENOUGH MOISTURE
IN PLACE AHEAD OF THE NEXT STORM SYSTEM TO FOSTER THE DEVELOPMENT OF
SCATTERED SHOWERS AND THUNDERSTORMS DURING THE MID MORNING THROUGH
THE EVENING HOURS. CLOUD TO GROUND LIGHTNING...GUSTY/ERRATIC
WINDS...A BRIEF HEAVY DOWNPOUR...AND SMALL HAIL ARE ALL POSSIBLE
WITH THE STRONGER ACTIVITY.

THE NEXT STORM SYSTEM ARRIVES TOMORROW AND PERSISTS THROUGH THE
HOLIDAY WEEKEND. SHOWERS AND THUNDERSTORMS WILL GROW MORE NUMEROUS
ACROSS THE REGION...WITH THE GREATEST COVERAGE IN ACTIVITY EXPECTED
SATURDAY. TEMPERATURES WILL TREND COOLER AND HUMIDITY WILL TREND
HIGHER. SNOW LEVELS WILL BE BETWEEN 8-9KFT...FALLING TO 7KFT UNDER
THE HEAVIEST ACTIVITY.

&&

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

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...STRUTHWOLF

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)




000
FXUS65 KSLC 210230
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
830 PM MDT WED MAY 20 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. SEVERAL AREAS OF LOW PRESSURE WILL
CROSS THE GREAT BASIN FRIDAY THROUGH TUESDAY.

&&

.DISCUSSION...A BROAD UPPER TROUGH IS SITUATED ALONG THE PACIFIC
COAST THIS EVENING...INDUCING A DEEP LAYER SOUTHWESTERLY FLOW
ALOFT DOWNSTREAM ACROSS THE GREAT BASIN. A SHORTWAVE TROUGH
EMBEDDED WITHIN THIS FLOW IS CURRENTLY LIFTING NORTHEAST ACROSS
EASTERN NV/WEST CENTRAL UT...AND LARGE SCALE ASCENT AHEAD OF THIS
FEATURE CONTINUES TO WORK ON A MODESTLY MOIST UNSTABLE AIRMASS
ACROSS NORTHERN UT TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS.
THE BOUNDARY LAYER HAS DRIED OUT CONSIDERABLY OVER WHAT HAD BEEN
OBSERVED IN RECENT DAYS...AND THUS ARE SEEING A MORE IN THE WAY OF
LOCALLY STRONG MICROBURST WINDS WITH THIS ACTIVITY.

IN THE WAKE OF THIS WAVE SUBSIDENCE HAS OVERSPREAD MUCH OF
SOUTHERN UT RESULTING IN MOSTLY CLEAR SKIES THIS EVENING. AS THIS
WAVE CONTINUES NORTHWARD AND EVENTUALLY EXITS NORTHERN UT
OVERNIGHT SHOULD SEE A CONTINUED DOWNWARD TREND IN CONVECTIVE
ACTIVITY FROM SOUTH TO NORTH. UPDATED THE FORECAST TO REMOVE POPS
AND REDUCE SKY COVER ACROSS SOUTHERN UT...AS WELL AS KEEP POPS
ACROSS THE NORTH IN THE SCATTERED CATEGORY.

ANOTHER EJECTING WAVE IS FORECAST TO WORK ITS WAY ACROSS THE
FORECAST AREA DURING THE DAY THURSDAY...LIKELY RESULTING IN
ANOTHER ROUND OF SCATTERED CONVECTION DURING THE AFTERNOON AND
EVENING HOURS. THE MAIN UPPER TROUGH ALONG THE COAST IS FORECAST
TO SLOWLY MOVE INLAND FRIDAY THROUGH MUCH OF THE UPCOMING
WEEKEND...WITH A SECONDARY WAVE POSSIBLY DROPPING INTO THE
FORECAST AREA FROM THE NORTHWST FOR MEMORIAL DAY. THE END RESULT
LOOKS TO BE A FAIRLY COOL AND UNSETTLED WEEKEND ACROSS THE
FORECAST AREA.

&&

.AVIATION...NORTHERLY OUTFLOW WINDS WILL LIKELY PREVAIL AT KSLC
THROUGH ROUGHLY 04Z BEFORE DIMINISHING AND SWITCHING BACK TO THE
SOUTH. THERE REMAINS A 30 PERCENT CHANCE ADDITIONAL SHOWERS WILL
IMPACT THE TERMINAL THROUGH AROUND 07Z OR SO WITH THE POTENTIAL
FOR GUSTY ERRATIC WINDS. CONDITIONS ARE EXPECTED TO REMAIN VFR
THROUGHOUT...HOWEVER MAY SEE CIGS BRIEFLY DROP INTO THE 5000 FOOT
RANGE WITH THESE SHOWERS.

&&

.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)





000
FXUS65 KSLC 210230
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
830 PM MDT WED MAY 20 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. SEVERAL AREAS OF LOW PRESSURE WILL
CROSS THE GREAT BASIN FRIDAY THROUGH TUESDAY.

&&

.DISCUSSION...A BROAD UPPER TROUGH IS SITUATED ALONG THE PACIFIC
COAST THIS EVENING...INDUCING A DEEP LAYER SOUTHWESTERLY FLOW
ALOFT DOWNSTREAM ACROSS THE GREAT BASIN. A SHORTWAVE TROUGH
EMBEDDED WITHIN THIS FLOW IS CURRENTLY LIFTING NORTHEAST ACROSS
EASTERN NV/WEST CENTRAL UT...AND LARGE SCALE ASCENT AHEAD OF THIS
FEATURE CONTINUES TO WORK ON A MODESTLY MOIST UNSTABLE AIRMASS
ACROSS NORTHERN UT TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS.
THE BOUNDARY LAYER HAS DRIED OUT CONSIDERABLY OVER WHAT HAD BEEN
OBSERVED IN RECENT DAYS...AND THUS ARE SEEING A MORE IN THE WAY OF
LOCALLY STRONG MICROBURST WINDS WITH THIS ACTIVITY.

IN THE WAKE OF THIS WAVE SUBSIDENCE HAS OVERSPREAD MUCH OF
SOUTHERN UT RESULTING IN MOSTLY CLEAR SKIES THIS EVENING. AS THIS
WAVE CONTINUES NORTHWARD AND EVENTUALLY EXITS NORTHERN UT
OVERNIGHT SHOULD SEE A CONTINUED DOWNWARD TREND IN CONVECTIVE
ACTIVITY FROM SOUTH TO NORTH. UPDATED THE FORECAST TO REMOVE POPS
AND REDUCE SKY COVER ACROSS SOUTHERN UT...AS WELL AS KEEP POPS
ACROSS THE NORTH IN THE SCATTERED CATEGORY.

ANOTHER EJECTING WAVE IS FORECAST TO WORK ITS WAY ACROSS THE
FORECAST AREA DURING THE DAY THURSDAY...LIKELY RESULTING IN
ANOTHER ROUND OF SCATTERED CONVECTION DURING THE AFTERNOON AND
EVENING HOURS. THE MAIN UPPER TROUGH ALONG THE COAST IS FORECAST
TO SLOWLY MOVE INLAND FRIDAY THROUGH MUCH OF THE UPCOMING
WEEKEND...WITH A SECONDARY WAVE POSSIBLY DROPPING INTO THE
FORECAST AREA FROM THE NORTHWST FOR MEMORIAL DAY. THE END RESULT
LOOKS TO BE A FAIRLY COOL AND UNSETTLED WEEKEND ACROSS THE
FORECAST AREA.

&&

.AVIATION...NORTHERLY OUTFLOW WINDS WILL LIKELY PREVAIL AT KSLC
THROUGH ROUGHLY 04Z BEFORE DIMINISHING AND SWITCHING BACK TO THE
SOUTH. THERE REMAINS A 30 PERCENT CHANCE ADDITIONAL SHOWERS WILL
IMPACT THE TERMINAL THROUGH AROUND 07Z OR SO WITH THE POTENTIAL
FOR GUSTY ERRATIC WINDS. CONDITIONS ARE EXPECTED TO REMAIN VFR
THROUGHOUT...HOWEVER MAY SEE CIGS BRIEFLY DROP INTO THE 5000 FOOT
RANGE WITH THESE SHOWERS.

&&

.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)





000
FXUS65 KSLC 210230
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
830 PM MDT WED MAY 20 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. SEVERAL AREAS OF LOW PRESSURE WILL
CROSS THE GREAT BASIN FRIDAY THROUGH TUESDAY.

&&

.DISCUSSION...A BROAD UPPER TROUGH IS SITUATED ALONG THE PACIFIC
COAST THIS EVENING...INDUCING A DEEP LAYER SOUTHWESTERLY FLOW
ALOFT DOWNSTREAM ACROSS THE GREAT BASIN. A SHORTWAVE TROUGH
EMBEDDED WITHIN THIS FLOW IS CURRENTLY LIFTING NORTHEAST ACROSS
EASTERN NV/WEST CENTRAL UT...AND LARGE SCALE ASCENT AHEAD OF THIS
FEATURE CONTINUES TO WORK ON A MODESTLY MOIST UNSTABLE AIRMASS
ACROSS NORTHERN UT TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS.
THE BOUNDARY LAYER HAS DRIED OUT CONSIDERABLY OVER WHAT HAD BEEN
OBSERVED IN RECENT DAYS...AND THUS ARE SEEING A MORE IN THE WAY OF
LOCALLY STRONG MICROBURST WINDS WITH THIS ACTIVITY.

IN THE WAKE OF THIS WAVE SUBSIDENCE HAS OVERSPREAD MUCH OF
SOUTHERN UT RESULTING IN MOSTLY CLEAR SKIES THIS EVENING. AS THIS
WAVE CONTINUES NORTHWARD AND EVENTUALLY EXITS NORTHERN UT
OVERNIGHT SHOULD SEE A CONTINUED DOWNWARD TREND IN CONVECTIVE
ACTIVITY FROM SOUTH TO NORTH. UPDATED THE FORECAST TO REMOVE POPS
AND REDUCE SKY COVER ACROSS SOUTHERN UT...AS WELL AS KEEP POPS
ACROSS THE NORTH IN THE SCATTERED CATEGORY.

ANOTHER EJECTING WAVE IS FORECAST TO WORK ITS WAY ACROSS THE
FORECAST AREA DURING THE DAY THURSDAY...LIKELY RESULTING IN
ANOTHER ROUND OF SCATTERED CONVECTION DURING THE AFTERNOON AND
EVENING HOURS. THE MAIN UPPER TROUGH ALONG THE COAST IS FORECAST
TO SLOWLY MOVE INLAND FRIDAY THROUGH MUCH OF THE UPCOMING
WEEKEND...WITH A SECONDARY WAVE POSSIBLY DROPPING INTO THE
FORECAST AREA FROM THE NORTHWST FOR MEMORIAL DAY. THE END RESULT
LOOKS TO BE A FAIRLY COOL AND UNSETTLED WEEKEND ACROSS THE
FORECAST AREA.

&&

.AVIATION...NORTHERLY OUTFLOW WINDS WILL LIKELY PREVAIL AT KSLC
THROUGH ROUGHLY 04Z BEFORE DIMINISHING AND SWITCHING BACK TO THE
SOUTH. THERE REMAINS A 30 PERCENT CHANCE ADDITIONAL SHOWERS WILL
IMPACT THE TERMINAL THROUGH AROUND 07Z OR SO WITH THE POTENTIAL
FOR GUSTY ERRATIC WINDS. CONDITIONS ARE EXPECTED TO REMAIN VFR
THROUGHOUT...HOWEVER MAY SEE CIGS BRIEFLY DROP INTO THE 5000 FOOT
RANGE WITH THESE SHOWERS.

&&

.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)




000
FXUS65 KSLC 210230
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
830 PM MDT WED MAY 20 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. SEVERAL AREAS OF LOW PRESSURE WILL
CROSS THE GREAT BASIN FRIDAY THROUGH TUESDAY.

&&

.DISCUSSION...A BROAD UPPER TROUGH IS SITUATED ALONG THE PACIFIC
COAST THIS EVENING...INDUCING A DEEP LAYER SOUTHWESTERLY FLOW
ALOFT DOWNSTREAM ACROSS THE GREAT BASIN. A SHORTWAVE TROUGH
EMBEDDED WITHIN THIS FLOW IS CURRENTLY LIFTING NORTHEAST ACROSS
EASTERN NV/WEST CENTRAL UT...AND LARGE SCALE ASCENT AHEAD OF THIS
FEATURE CONTINUES TO WORK ON A MODESTLY MOIST UNSTABLE AIRMASS
ACROSS NORTHERN UT TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS.
THE BOUNDARY LAYER HAS DRIED OUT CONSIDERABLY OVER WHAT HAD BEEN
OBSERVED IN RECENT DAYS...AND THUS ARE SEEING A MORE IN THE WAY OF
LOCALLY STRONG MICROBURST WINDS WITH THIS ACTIVITY.

IN THE WAKE OF THIS WAVE SUBSIDENCE HAS OVERSPREAD MUCH OF
SOUTHERN UT RESULTING IN MOSTLY CLEAR SKIES THIS EVENING. AS THIS
WAVE CONTINUES NORTHWARD AND EVENTUALLY EXITS NORTHERN UT
OVERNIGHT SHOULD SEE A CONTINUED DOWNWARD TREND IN CONVECTIVE
ACTIVITY FROM SOUTH TO NORTH. UPDATED THE FORECAST TO REMOVE POPS
AND REDUCE SKY COVER ACROSS SOUTHERN UT...AS WELL AS KEEP POPS
ACROSS THE NORTH IN THE SCATTERED CATEGORY.

ANOTHER EJECTING WAVE IS FORECAST TO WORK ITS WAY ACROSS THE
FORECAST AREA DURING THE DAY THURSDAY...LIKELY RESULTING IN
ANOTHER ROUND OF SCATTERED CONVECTION DURING THE AFTERNOON AND
EVENING HOURS. THE MAIN UPPER TROUGH ALONG THE COAST IS FORECAST
TO SLOWLY MOVE INLAND FRIDAY THROUGH MUCH OF THE UPCOMING
WEEKEND...WITH A SECONDARY WAVE POSSIBLY DROPPING INTO THE
FORECAST AREA FROM THE NORTHWST FOR MEMORIAL DAY. THE END RESULT
LOOKS TO BE A FAIRLY COOL AND UNSETTLED WEEKEND ACROSS THE
FORECAST AREA.

&&

.AVIATION...NORTHERLY OUTFLOW WINDS WILL LIKELY PREVAIL AT KSLC
THROUGH ROUGHLY 04Z BEFORE DIMINISHING AND SWITCHING BACK TO THE
SOUTH. THERE REMAINS A 30 PERCENT CHANCE ADDITIONAL SHOWERS WILL
IMPACT THE TERMINAL THROUGH AROUND 07Z OR SO WITH THE POTENTIAL
FOR GUSTY ERRATIC WINDS. CONDITIONS ARE EXPECTED TO REMAIN VFR
THROUGHOUT...HOWEVER MAY SEE CIGS BRIEFLY DROP INTO THE 5000 FOOT
RANGE WITH THESE SHOWERS.

&&

.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)




000
FXUS65 KSLC 202215
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
415 PM MDT WED MAY 20 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. SEVERAL AREAS OF LOW PRESSURE WILL
CROSS THE GREAT BASIN FRIDAY THROUGH TUESDAY.

&&

.SHORT TERM (THROUGH 06Z SUNDAY)...THE MEAN POSITION OF THE UPPER
LOW OFF THE CALIFORNIA COAST WILL CONTINUE EJECTING A SERIES OF
VORTICITY LOBES NORTH ACROSS THE GREAT BASIN THROUGH AT LEAST
EARLY FRIDAY. THE FIRST LOBE JUST OFF THE SOUTHWEST CORNER OF UTAH
WILL GENERATE AN INCREASING AREA OF SCATTERED CONVECTION ACROSS
SOUTHERN/CENTRAL UTAH LATE THIS AFTERNOON/EARLY EVENING. THIS LOBE
WILL REACH NORTHERN UTAH AROUND MID-EVENING...WITH DYNAMIC
SUBSIDENCE PRODUCING A DECREASING TREND TO CONVECTION ACROSS THE
SOUTH LATE THIS EVENING.

ACROSS THE NORTH CONVECTION APPEARS A BIT STRONGER UNDERNEATH
INCREASING DIVERGENCE ALOFT. THIS ACTIVITY WILL LIKELY INCREASE IN
INTENSITY AND AREAL COVERAGE OVER MAINLY NORTHWEST UTAH LATE THIS
EVENING AS THE VORTICITY LOBE MOVES NORTH THROUGH THE AREA AND
DIVERGENCE ALOFT PEAKS. SMALL HAIL AND BRIEF HEAVY RAIN THE LIKELY
RESULT IN STRONGER CONVECTION OVER NORTHERN UTAH OVERNIGHT.

THE SECOND VORTICITY LOBE WILL REACH SOUTHERN UTAH EARLY THURSDAY.
THIS SECOND FEATURE SHOULD GENERATE SCATTERED CONVECTION ONCE
AGAIN...WITH THIS ACTIVITY PEAKING ACROSS THE NORTH DURING THE
AFTERNOON HOURS. A THIRD FEATURE WILL FOLLOW EARLY FRIDAY...BUT WILL
BE CAUGHT IN THE ORBIT OF THE UPPER LOW NOW CENTERED INLAND OVER
SOUTHERN CALIFORNIA. THIS THIRD FEATURE WILL TURN EAST TOWARDS
NEVADA DURING THE AFTERNOON...WITH IMPACTS CONFINED TO MAINLY TO
WEST-CENTRAL AND CENTRAL UTAH.

A PROLONGED PERIOD OF COOL/WET CONDITIONS IS ANTICIPATED AS THE
SOUTHERN CALIFORNIA UPPER LOW TURNS NORTH-NORTHEAST AND TRACKS
SLOWLY THROUGH THE GREAT BASIN. PLENTY OF MOISTURE AND SOLID
DYNAMIC LIFT SHOULD SERVE TO PRODUCE WIDESPREAD AND SUBSTANTIAL
VALLEY RAIN AND MOUNTAIN SNOW THROUGH AT LEAST SATURDAY EVENING.
DEEP LAYER AND MOIST NORTHWEST FLOW WARM ADVECTION COULD SET UP
ACROSS NORTHWEST UTAH LATE SATURDAY. THE LATEST GFS IS SHOWS THIS
COMING TO PASS...WITH THE ECMWF MAINTAIN A MORE EASTERLY COMPONENT
TO THE FLOW. FOR NOW WILL FOLLOW THE GFS SOLUTION AND WILL BOOST
POPS/QPFS ACCORDINGLY.

.LONG TERM (AFTER 06Z SUNDAY)...MODEL TO MODEL AND RUN TO RUN
CONSISTENCY ISSUES ARE HAVING A SIGNIFICANT IMPACT ON THE
CONFIDENCE OF ANY PARTICULAR SOLUTION AFTER SATURDAY EVENING. AN
UPPER LEVEL LOW IS EXPECTED TO BE SLOWLY PUSHED SOUTHEASTWARD
SATURDAY EVENING THROUGH THE PACIFIC NORTHWEST INTO THE GREAT
BASIN...THOUGH TIMING OF THIS FEATURE IS SIGNIFICANTLY DIFFERENT
ACROSS THE 12Z MODEL SUITE. ANOTHER SOMEWHAT WEAKER TROUGH IS
FORECAST TO IMPACT THE REGION EARLY NEXT WEEK.

GIVEN THE CONSISTENCY ISSUES...CONFIDENCE IN TIMING/LOCATION OF
THESE FEATURES IS LOW AT BEST. KEPT THE TREND OF THE PREVIOUS
FORECAST WITH ELEVATED POPS THROUGH THE LONG TERM FORECAST. THE
MAIN MESSAGE WILL CONTINUE TO BE...UNSETTLED CONDITIONS WITH THE
POTENTIAL FOR PRECIPITATION WILL PERSIST THROUGH THE END OF THE
WEEKEND...THROUGH MEMORIAL DAY...AND INTO EARLY NEXT WEEK.

&&

.AVIATION...PRIMARY OPERATIONAL CONCERNS AT THE KSLC AIRPORT REMAIN
FOCUSED ON SHOWERS AND ISOLATED THUNDERSTORM IMPACTS THROUGH THIS
EVENING...AND ASSOCIATED WINDS. A LULL IN ACTIVITY THROUGH 01Z IS
EXPECTED BEFORE ADDITIONAL STORMS ARE EXPECTED TO MOVE THROUGH IN
THE 02Z-05Z WINDOW. A SWITCH TO PREVAILING NORTHWEST WINDS IS A
LOW CONFIDENCE FORECAST BUT IS MOST LIKELY IN THE 23-01Z WINDOW.
AFTER THAT PREVAILING SOUTHERLY WINDS ARE EXPECTED WITH PERIODIC
CIGS AOB 6000FT AGL DURING STORM ACTIVITY.

&&

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

$$

CONGER/KRUSE/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)




000
FXUS65 KSLC 202215
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
415 PM MDT WED MAY 20 2015

.SYNOPSIS...SEVERAL WEATHER DISTURBANCES WILL CROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. SEVERAL AREAS OF LOW PRESSURE WILL
CROSS THE GREAT BASIN FRIDAY THROUGH TUESDAY.

&&

.SHORT TERM (THROUGH 06Z SUNDAY)...THE MEAN POSITION OF THE UPPER
LOW OFF THE CALIFORNIA COAST WILL CONTINUE EJECTING A SERIES OF
VORTICITY LOBES NORTH ACROSS THE GREAT BASIN THROUGH AT LEAST
EARLY FRIDAY. THE FIRST LOBE JUST OFF THE SOUTHWEST CORNER OF UTAH
WILL GENERATE AN INCREASING AREA OF SCATTERED CONVECTION ACROSS
SOUTHERN/CENTRAL UTAH LATE THIS AFTERNOON/EARLY EVENING. THIS LOBE
WILL REACH NORTHERN UTAH AROUND MID-EVENING...WITH DYNAMIC
SUBSIDENCE PRODUCING A DECREASING TREND TO CONVECTION ACROSS THE
SOUTH LATE THIS EVENING.

ACROSS THE NORTH CONVECTION APPEARS A BIT STRONGER UNDERNEATH
INCREASING DIVERGENCE ALOFT. THIS ACTIVITY WILL LIKELY INCREASE IN
INTENSITY AND AREAL COVERAGE OVER MAINLY NORTHWEST UTAH LATE THIS
EVENING AS THE VORTICITY LOBE MOVES NORTH THROUGH THE AREA AND
DIVERGENCE ALOFT PEAKS. SMALL HAIL AND BRIEF HEAVY RAIN THE LIKELY
RESULT IN STRONGER CONVECTION OVER NORTHERN UTAH OVERNIGHT.

THE SECOND VORTICITY LOBE WILL REACH SOUTHERN UTAH EARLY THURSDAY.
THIS SECOND FEATURE SHOULD GENERATE SCATTERED CONVECTION ONCE
AGAIN...WITH THIS ACTIVITY PEAKING ACROSS THE NORTH DURING THE
AFTERNOON HOURS. A THIRD FEATURE WILL FOLLOW EARLY FRIDAY...BUT WILL
BE CAUGHT IN THE ORBIT OF THE UPPER LOW NOW CENTERED INLAND OVER
SOUTHERN CALIFORNIA. THIS THIRD FEATURE WILL TURN EAST TOWARDS
NEVADA DURING THE AFTERNOON...WITH IMPACTS CONFINED TO MAINLY TO
WEST-CENTRAL AND CENTRAL UTAH.

A PROLONGED PERIOD OF COOL/WET CONDITIONS IS ANTICIPATED AS THE
SOUTHERN CALIFORNIA UPPER LOW TURNS NORTH-NORTHEAST AND TRACKS
SLOWLY THROUGH THE GREAT BASIN. PLENTY OF MOISTURE AND SOLID
DYNAMIC LIFT SHOULD SERVE TO PRODUCE WIDESPREAD AND SUBSTANTIAL
VALLEY RAIN AND MOUNTAIN SNOW THROUGH AT LEAST SATURDAY EVENING.
DEEP LAYER AND MOIST NORTHWEST FLOW WARM ADVECTION COULD SET UP
ACROSS NORTHWEST UTAH LATE SATURDAY. THE LATEST GFS IS SHOWS THIS
COMING TO PASS...WITH THE ECMWF MAINTAIN A MORE EASTERLY COMPONENT
TO THE FLOW. FOR NOW WILL FOLLOW THE GFS SOLUTION AND WILL BOOST
POPS/QPFS ACCORDINGLY.

.LONG TERM (AFTER 06Z SUNDAY)...MODEL TO MODEL AND RUN TO RUN
CONSISTENCY ISSUES ARE HAVING A SIGNIFICANT IMPACT ON THE
CONFIDENCE OF ANY PARTICULAR SOLUTION AFTER SATURDAY EVENING. AN
UPPER LEVEL LOW IS EXPECTED TO BE SLOWLY PUSHED SOUTHEASTWARD
SATURDAY EVENING THROUGH THE PACIFIC NORTHWEST INTO THE GREAT
BASIN...THOUGH TIMING OF THIS FEATURE IS SIGNIFICANTLY DIFFERENT
ACROSS THE 12Z MODEL SUITE. ANOTHER SOMEWHAT WEAKER TROUGH IS
FORECAST TO IMPACT THE REGION EARLY NEXT WEEK.

GIVEN THE CONSISTENCY ISSUES...CONFIDENCE IN TIMING/LOCATION OF
THESE FEATURES IS LOW AT BEST. KEPT THE TREND OF THE PREVIOUS
FORECAST WITH ELEVATED POPS THROUGH THE LONG TERM FORECAST. THE
MAIN MESSAGE WILL CONTINUE TO BE...UNSETTLED CONDITIONS WITH THE
POTENTIAL FOR PRECIPITATION WILL PERSIST THROUGH THE END OF THE
WEEKEND...THROUGH MEMORIAL DAY...AND INTO EARLY NEXT WEEK.

&&

.AVIATION...PRIMARY OPERATIONAL CONCERNS AT THE KSLC AIRPORT REMAIN
FOCUSED ON SHOWERS AND ISOLATED THUNDERSTORM IMPACTS THROUGH THIS
EVENING...AND ASSOCIATED WINDS. A LULL IN ACTIVITY THROUGH 01Z IS
EXPECTED BEFORE ADDITIONAL STORMS ARE EXPECTED TO MOVE THROUGH IN
THE 02Z-05Z WINDOW. A SWITCH TO PREVAILING NORTHWEST WINDS IS A
LOW CONFIDENCE FORECAST BUT IS MOST LIKELY IN THE 23-01Z WINDOW.
AFTER THAT PREVAILING SOUTHERLY WINDS ARE EXPECTED WITH PERIODIC
CIGS AOB 6000FT AGL DURING STORM ACTIVITY.

&&

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

$$

CONGER/KRUSE/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)





000
FXUS65 KSLC 201645
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1045 AM MDT WED MAY 20 2015

.SYNOPSIS...A LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
SEND A COUPLE OF WEATHER DISTURBANCES NORTH ACROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. THIS LOW PRESSURE WILL MOVE INTO
AND THEN SLOWLY THROUGH THE REGION THIS HOLIDAY WEEKEND.

&&

.DISCUSSION...DEFORMATION AXIS NEAR THE IDAHO BORDER STILL THE
FOCUS OF A FEW LIGHT SHOWERS LATE THIS MORNING. THIS AXIS WILL
EXIT THE STATE TO THE NORTH SHORTLY AND END ANY ORGANIZED SHOWERS
ACROSS THE NORTH.

MINIMAL CLOUD COVER ACROSS THE SOUTHERN TWO-THIRDS OF THE STATE
WILL ALLOW FOR GOOD SURFACE HEATING AND THE DEVELOPMENT OF HIGH
TERRAIN SHOWERS AND ISOLATED THUNDERSTORMS BY EARLY AFTERNOON.
THESE SHOWERS AND STORMS WILL GRADUALLY INCREASE IN AREAL COVERAGE
AS THEY EXPAND INTO NORTHERN UTAH DURING THE AFTERNOON HOURS.

A VORTICITY MAXIMUM OVER SOUTHERN CALIFORNIA WILL EJECT NORTH
OUT OF THE MEAN UPPER LOW CURRENTLY POSITIONED NEAR THE CALIFORNIA
COAST. THIS VORTICITY MAX WILL STRETCH INTO SOUTHWEST UTAH LATE
THIS AFTERNOON AND GENERATE BETTER ORGANIZED AND SOMEWHAT MORE
INTENSE CONVECTION. THIS ACTIVITY WILL CONTINUE NORTH THROUGH
MAINLY THE WESTERN HALF OF UTAH THIS EVENING. A FEW STORM MAY
APPROACH SEVERE LIMITS ACROSS NORTHWEST UTAH WITH SUPPORT FROM
STRONG DIVERGENCE ALOFT.

A SECOND TRIALING VORTICITY LOBE THURSDAY SHOULD SERVE TO FIRE OFF
ANOTHER ROUND OF SCATTERED CONVECTION THURSDAY AFTERNOON/EVENING.
BY FRIDAY THE UPPER LOW OFF THE CALIFORNIA COAST WILL MOVE EAST
THROUGH SOUTHERN CALIFORNIA FRIDAY...THEN TURN NORTHEAST AND MOVE
SLOWLY THROUGH THE GREAT BASIN FRIDAY NIGHT THROUGH EARLY SUNDAY.

&&

.AVIATION...THE MOIST AND SOMEWHAT UNSTABLE AIR MASS IN PLACE
ACROSS NORTHERN UTAH WILL SPAWN ANOTHER ROUND OF SHOWERS/ISOLATED
THUNDERSTORMS OVER AND NEAR THE TERMINAL THIS AFTERNOON. MOST OF
THIS ACTIVITY WILL ORIGINATE ACROSS THE SURROUNDING HIGHER
TERRAIN...THEN DRIFT INTO THE VALLEYS AFTER AROUND 19Z. A WEATHER
DISTURBANCE LIFTING NORTH THROUGH WESTERN UTAH THIS AFTERNOON WILL
REACH THE TERMINAL AREA EARLY THIS EVENING. SHOWERS ASSOCIATED
WITH THIS FEATURE COULD GENERATE MVFR CONDITIONS IN HEAVIER
PRECIP. ISOLATED THUNDERSTORMS ARE POSSIBLE DURING THE EARLY AND
MID-EVENING HOURS.

&&

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

$$

CONGER

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)




000
FXUS65 KSLC 201645
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1045 AM MDT WED MAY 20 2015

.SYNOPSIS...A LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
SEND A COUPLE OF WEATHER DISTURBANCES NORTH ACROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. THIS LOW PRESSURE WILL MOVE INTO
AND THEN SLOWLY THROUGH THE REGION THIS HOLIDAY WEEKEND.

&&

.DISCUSSION...DEFORMATION AXIS NEAR THE IDAHO BORDER STILL THE
FOCUS OF A FEW LIGHT SHOWERS LATE THIS MORNING. THIS AXIS WILL
EXIT THE STATE TO THE NORTH SHORTLY AND END ANY ORGANIZED SHOWERS
ACROSS THE NORTH.

MINIMAL CLOUD COVER ACROSS THE SOUTHERN TWO-THIRDS OF THE STATE
WILL ALLOW FOR GOOD SURFACE HEATING AND THE DEVELOPMENT OF HIGH
TERRAIN SHOWERS AND ISOLATED THUNDERSTORMS BY EARLY AFTERNOON.
THESE SHOWERS AND STORMS WILL GRADUALLY INCREASE IN AREAL COVERAGE
AS THEY EXPAND INTO NORTHERN UTAH DURING THE AFTERNOON HOURS.

A VORTICITY MAXIMUM OVER SOUTHERN CALIFORNIA WILL EJECT NORTH
OUT OF THE MEAN UPPER LOW CURRENTLY POSITIONED NEAR THE CALIFORNIA
COAST. THIS VORTICITY MAX WILL STRETCH INTO SOUTHWEST UTAH LATE
THIS AFTERNOON AND GENERATE BETTER ORGANIZED AND SOMEWHAT MORE
INTENSE CONVECTION. THIS ACTIVITY WILL CONTINUE NORTH THROUGH
MAINLY THE WESTERN HALF OF UTAH THIS EVENING. A FEW STORM MAY
APPROACH SEVERE LIMITS ACROSS NORTHWEST UTAH WITH SUPPORT FROM
STRONG DIVERGENCE ALOFT.

A SECOND TRIALING VORTICITY LOBE THURSDAY SHOULD SERVE TO FIRE OFF
ANOTHER ROUND OF SCATTERED CONVECTION THURSDAY AFTERNOON/EVENING.
BY FRIDAY THE UPPER LOW OFF THE CALIFORNIA COAST WILL MOVE EAST
THROUGH SOUTHERN CALIFORNIA FRIDAY...THEN TURN NORTHEAST AND MOVE
SLOWLY THROUGH THE GREAT BASIN FRIDAY NIGHT THROUGH EARLY SUNDAY.

&&

.AVIATION...THE MOIST AND SOMEWHAT UNSTABLE AIR MASS IN PLACE
ACROSS NORTHERN UTAH WILL SPAWN ANOTHER ROUND OF SHOWERS/ISOLATED
THUNDERSTORMS OVER AND NEAR THE TERMINAL THIS AFTERNOON. MOST OF
THIS ACTIVITY WILL ORIGINATE ACROSS THE SURROUNDING HIGHER
TERRAIN...THEN DRIFT INTO THE VALLEYS AFTER AROUND 19Z. A WEATHER
DISTURBANCE LIFTING NORTH THROUGH WESTERN UTAH THIS AFTERNOON WILL
REACH THE TERMINAL AREA EARLY THIS EVENING. SHOWERS ASSOCIATED
WITH THIS FEATURE COULD GENERATE MVFR CONDITIONS IN HEAVIER
PRECIP. ISOLATED THUNDERSTORMS ARE POSSIBLE DURING THE EARLY AND
MID-EVENING HOURS.

&&

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

$$

CONGER

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)




000
FXUS65 KSLC 201645
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1045 AM MDT WED MAY 20 2015

.SYNOPSIS...A LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL
SEND A COUPLE OF WEATHER DISTURBANCES NORTH ACROSS THE GREAT
BASIN THROUGH THURSDAY NIGHT. THIS LOW PRESSURE WILL MOVE INTO
AND THEN SLOWLY THROUGH THE REGION THIS HOLIDAY WEEKEND.

&&

.DISCUSSION...DEFORMATION AXIS NEAR THE IDAHO BORDER STILL THE
FOCUS OF A FEW LIGHT SHOWERS LATE THIS MORNING. THIS AXIS WILL
EXIT THE STATE TO THE NORTH SHORTLY AND END ANY ORGANIZED SHOWERS
ACROSS THE NORTH.

MINIMAL CLOUD COVER ACROSS THE SOUTHERN TWO-THIRDS OF THE STATE
WILL ALLOW FOR GOOD SURFACE HEATING AND THE DEVELOPMENT OF HIGH
TERRAIN SHOWERS AND ISOLATED THUNDERSTORMS BY EARLY AFTERNOON.
THESE SHOWERS AND STORMS WILL GRADUALLY INCREASE IN AREAL COVERAGE
AS THEY EXPAND INTO NORTHERN UTAH DURING THE AFTERNOON HOURS.

A VORTICITY MAXIMUM OVER SOUTHERN CALIFORNIA WILL EJECT NORTH
OUT OF THE MEAN UPPER LOW CURRENTLY POSITIONED NEAR THE CALIFORNIA
COAST. THIS VORTICITY MAX WILL STRETCH INTO SOUTHWEST UTAH LATE
THIS AFTERNOON AND GENERATE BETTER ORGANIZED AND SOMEWHAT MORE
INTENSE CONVECTION. THIS ACTIVITY WILL CONTINUE NORTH THROUGH
MAINLY THE WESTERN HALF OF UTAH THIS EVENING. A FEW STORM MAY
APPROACH SEVERE LIMITS ACROSS NORTHWEST UTAH WITH SUPPORT FROM
STRONG DIVERGENCE ALOFT.

A SECOND TRIALING VORTICITY LOBE THURSDAY SHOULD SERVE TO FIRE OFF
ANOTHER ROUND OF SCATTERED CONVECTION THURSDAY AFTERNOON/EVENING.
BY FRIDAY THE UPPER LOW OFF THE CALIFORNIA COAST WILL MOVE EAST
THROUGH SOUTHERN CALIFORNIA FRIDAY...THEN TURN NORTHEAST AND MOVE
SLOWLY THROUGH THE GREAT BASIN FRIDAY NIGHT THROUGH EARLY SUNDAY.

&&

.AVIATION...THE MOIST AND SOMEWHAT UNSTABLE AIR MASS IN PLACE
ACROSS NORTHERN UTAH WILL SPAWN ANOTHER ROUND OF SHOWERS/ISOLATED
THUNDERSTORMS OVER AND NEAR THE TERMINAL THIS AFTERNOON. MOST OF
THIS ACTIVITY WILL ORIGINATE ACROSS THE SURROUNDING HIGHER
TERRAIN...THEN DRIFT INTO THE VALLEYS AFTER AROUND 19Z. A WEATHER
DISTURBANCE LIFTING NORTH THROUGH WESTERN UTAH THIS AFTERNOON WILL
REACH THE TERMINAL AREA EARLY THIS EVENING. SHOWERS ASSOCIATED
WITH THIS FEATURE COULD GENERATE MVFR CONDITIONS IN HEAVIER
PRECIP. ISOLATED THUNDERSTORMS ARE POSSIBLE DURING THE EARLY AND
MID-EVENING HOURS.

&&

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

$$

CONGER

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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