Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 061559
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
959 AM MDT MON JUL 6 2015

.SYNOPSIS...HIGH PRESSURE WILL REMAIN CENTERED OVER THE SOUTHERN
ROCKIES THROUGH MUCH OF THIS WEEK. ABUNDANT MOISTURE ALONG WITH
WEAK WEATHER DISTURBANCES MOVING THROUGH THE REGION WILL GENERATE
SHOWERS AND THUNDERSTORMS THROUGH MIDWEEK. A BROAD UPPER LOW
WILL MOVE THROUGH THE EASTERN GREAT BASIN LATE IN THE WEEK.


&&

.DISCUSSION...MORNING WATER VAPOR AND H5 ANALYSIS DEPICT
SUPPRESSED RIDGING OVER THE DESERT SOUTHWEST...WITH A MOIST RETURN
FLOW ACROSS SW UTAH. CYCLONIC FLOW EXISTS OVER THE NORTHERN
ROCKIES WITH AN EMBEDDED SHORT WAVE MOVING EAST ACROSS SOUTHERN
IDAHO ATTM. A BROAD CLOSED LOW SITS OFF THE CALI COAST MOVING AND
REMAINS NEARLY STATIONARY.

TWO AREAS TO FOCUS ON REGARDING CONVECTIVE POTENTIAL TODAY...THE
FAR NORTH ASSOCIATED WITH THE AFOREMENTIONED SHORT WAVE AND
CENTRAL/SOUTHERN UTAH WHERE A WEAK DISTURBANCE IN THE RETURN FLOW
WILL DEVELOP LATE MORNING. THE LATTER WILL MOST LIKELY BE THE
FOCUS FOR SHORT TERM WEATHER CONCERNS AS THE NORTH REMAINS
SOMEWHAT SUPPRESSED...THIS NOTED BY LOOKING AT MID LEVEL LAPSE
RATE PROFILES.

SCATTERED SHOWERS HAVE BEEN ONGOING THIS MORNING SOUTH OF
I-70...THIS INDICATIVE OF WEAK FORCING FROM THE DEVELOPING WAVE.

HRRR/RAP DEVELOP A BROAD AREA OF CONVECTION SOUTH OF I-70 BY 20Z.
SPC MESOANALYSIS SUPPORT A FAVORABLE THERMODYNAMIC ENVIRONMENT OF
THE DEEPLY MOIST AIRMASS IN PLACE ONCE HEATING OF THE DAY ENSUES
AND THE NOW PLENTIFUL CLOUD COVER THINS. PWAT REMAINS IN EXCESS
OF 1 INCH...AND MODEST INSTABILITY POTENTIAL EXISTS PER SPC SREF.
OPTED TO BUMP POPS TO HIGH CHANCE VALLEYS AND LIKELY SOME PRONE
AREAS ACROSS THE SOUTHERN MTNS THIS AFTERNOON AS TERRAIN BASED
CONVECTION SHOULD CONGEAL AND TRANSITION NORTH AS THE WAVE BECOMES
MORE DEVELOPED MID AFTERNOON. LOCALLY HEAVY RAIN REMAINS A
POTENTIAL.

THE NORTHERN SHORT WAVE WILL LIKELY SPAWN SCATTERED CONVECTION
ACROSS FAR NORTHERN UTAH THIS AFTERNOON...BUT HI-RES GUIDANCE NOT
AS ENTHUSED MOST LIKELY DUE TO MINIMAL MID LEVEL LAPSE RATES IN
PLACE. THE CENTRAL/SOUTHERN WASATCH FRONT SHOULD REMAIN LARGELY
DRY THROUGH THE AFTERNOON HOURS AS SUCH...BUT MAY SEE ENCROACHMENT
OF STORMS FROM THE SOUTH THIS EVENING. WILL FOCUS ON THIS
POTENTIAL THIS SHIFT.

OUTSIDE OF THE INCREASE OF POPS FOR THE SOUTH...UPDATED SKY COVER
TO FOLLOW LATEST TRENDS.

PREVIOUS DISCUSSION...PLENTY OF INSTABILITY TODAY AND TOMORROW
AND GIVEN THE COMBINATION OF WEAK WAVES AND TERRAIN CIRCULATIONS
SHOULD HAVE LITTLE ISSUES DEVELOPING ISOLATED TO SCATTERED
CONVECTION EACH DAY.

WEDNESDAY IS A TRANSITION DAY AS THE UPSTREAM CLOSED LOW MAKES ITS
WAY INTO CENTRAL CALIFORNIA. INCREASING DRY SOUTHWESTERLY FLOW WILL
LIMIT CONVECTION ACROSS THE SOUTH AND PROVIDE THE OPPORTUNITY FOR
THE DEVELOPMENT OF GUSTY WINDS ACROSS A FEW SOUTHWESTERN VALLEYS.
FURTHER NORTH AND EAST WHERE CONVECTION DOES FORM...IT WILL BE
TRANSITIONING TO HIGHER BASED ACTIVITY.

A PACIFIC STORM SYSTEM IS PROGGED TO MOVE ONSHORE OVER THE
CALIFORNIA COAST DURING THE DAY THURSDAY. THE APPROACH OF THE
SYSTEM WILL MOVE SOME DRIER AIR INTO WESTERN UTAH. GLOBAL MODELS
HAVE COME INTO BETTER AGREEMENT WITH THE TRACK OF THIS
SYSTEM...SWEEPING IT ACROSS UTAH THURSDAY NIGHT/FRIDAY AS IT
WEAKENS. THE PASSING SYSTEM WILL PROVIDE A FOCUS FOR A BIT OF
OVERNIGHT CONVECTION DURING THAT TIME...WITH SHOWERS LINGERING
OVER NORTHERN UTAH INTO FRIDAY AFTERNOON. HAVE RAISED POPS A
BIT...PRIMARILY FOR THURSDAY NIGHT...WITH THESE CURRENT TRENDS.
DRIER AIR IS EXPECTED TO MOVE BACK IN BEGINNING FRIDAY NIGHT AS
THE TROUGH EXITS AND HIGH PRESSURE CENTERED OVER THE PLAINS BUILDS
BACK INTO THE FORECAST AREA. THIS WOULD RESULT IN DRY AND STABLE
CONDITIONS FOR THE UPCOMING WEEKEND.

&&

.AVIATION...WINDS AT THE SLC TERMINAL ARE EXPECTED TO SWITCH TO THE
NORTHWEST BETWEEN 16Z AND 18Z TODAY. THERE IS A 20 PERCENT CHANCE OF
A SHOWER OR THUNDERSTORM IMPACTING THE TERMINAL THROUGH 00Z
TUESDAY...WITH CHANCES POTENTIALLY INCREASING AFTER 00Z. BRIEF HEAVY
RAIN AND MVFR CONDITIONS ARE POSSIBLE IF A SHOWER PASSES DIRECTLY
OVERHEAD...WITH GUSTY ERRATIC WINDS ONLY EXPECTED WITH STRONGER
STORMS.

&&

.FIRE WEATHER...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE THE RULE THROUGH TOMORROW. NEW LIGHTNING STARTS ARE THE PRIMARY
CONCERN...WITH SOME STORMS PROVIDING AN OPPORTUNITY FOR A WETTING
RAIN. THIS ESPECIALLY HOLDS TRUE FOR SOUTHERN/CENTRAL PORTIONS OF
THE DISTRICT. THE CONVECTIVE COVERAGE WILL KEEP TEMPERATURES DOWN
AND HUMIDITY UP A BIT.

A DRIER SOUTHWESTERLY FLOW ALOFT IS CURRENTLY ADVERTISED DURING
THE MIDDLE OF THE WEEK AHEAD OF AN APPROACHING UPPER LOW THAT WILL
MOVE THROUGH THE AREA FRIDAY. A DRY AND LOCALLY BREEZY SOUTHWESTERLY
FLOW DEVELOPS TRENDING HUMIDITY LOWER...ACROSS PRIMARILY THE FAR
SOUTHWEST VALLEYS WEDNESDAY AFTERNOON...THEN SPREADING NORTHEAST
THURSDAY. CONVECTION WILL STILL BE AROUND...THOUGH WETTING RAIN
BECOMES LESS OF A POSSIBILITY AS ACTIVITY BECOMES HIGHER BASED.

&&

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

$$

DISCUSSION...MERRILL/SCHOENING
PREVIOUS DISCUSSION...ROGOWSKI/TRAPHAGAN


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

FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)


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