Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 022204
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
404 PM MDT TUE JUN 2 2015

.SYNOPSIS...A WEAK PACIFIC STORM SYSTEM WILL GRAZE NORTHERN UTAH
WEDNESDAY AND WEDNESDAY NIGHT. A CLOSED LOW OFF THE CALIFORNIA
COAST WILL BEGIN TO SEND MOISTURE NORTH INTO UTAH ON
FRIDAY...CONTINUING INTO THE WEEKEND.

&&

.SHORT TERM (THROUGH 00Z FRIDAY)...A MEAN SOUTHWESTERLY FLOW ALOFT
PREVAILS ACROSS THE REGION THIS AFTERNOON...WHILE A STALLED FRONTAL
BOUNDARY REMAINS SITUATED ACROSS CENTRAL UTAH. TO THE SOUTH OF THIS
BOUNDARY A WARM AND VERY DRY AIRMASS RESIDES ACROSS SOUTHERN
UT...WHILE TO THE NORTH TEMPERATURES ARE CONSIDERABLY COOLER THIS
AFTERNOON AS COMPARED TO MONDAY. LINGERING MOISTURE NEAR THE ID
BORDER WILL SUPPORT A SMALL THREAT FOR SHOWERS AND THUNDERSTORMS
INTO THE EARLY EVENING HOURS...WHILE THE REMAINDER OF THE FORECAST
AREA REMAINS DRY.

A WEAK SHORTWAVE FEATURE CURRENTLY APPROACHING THE PACIFIC COAST IS
FORECAST TO ROTATE INLAND OVERNIGHT BEFORE EJECTING ACROSS THE
EASTERN GREAT BASIN WEDNESDAY. THIS COUPLED WITH MOISTURE IN PLACE
NORTH OF THE AFOREMENTIONED BOUNDARY WILL BRING A BETTER CHANCE FOR
SHOWERS AND THUNDERSTORMS NORTH OF I-80 DURING THE AFTERNOON...WITH
ADDITIONAL CONVECTION EXPECTED TO DEVELOP ACROSS NORTHEAST NV
POTENTIALLY SPREADING INTO THE WEST DESERT AND PERHAPS REACHING THE
WASATCH FRONT DURING THE EVENING HOURS. STRENGTHENING MID LEVEL WIND
FIELDS IN RESPONSE TO THE APPROACHING WAVE WILL ALLOW FOR SHEAR
VALUES SUPPORTIVE OF STRONGER ORGANIZED CONVECTION WITH GUSTY WINDS
BEING THE PRIMARY THREAT GIVEN A DEEPLY MIXED BOUNDARY LAYER.

THE NEXT UPSTREAM WAVE IS FORECAST TO DIG ALONG THE PACIFIC COAST
LATE WEDNESDAY INTO THURSDAY...BACKING THE FLOW ALOFT ACROSS THE
FORECAST AREA...AND ADVECTING THE DRIER AIR CURRENTLY IN PLACE
ACROSS SOUTHERN UT NORTHWARD ACROSS THE REMAINDER OF THE AREA. AS
SUCH HAVE CONTINUED WITH THE GOING TREND FOR THURSDAY ACROSS THE
NORTH.

.LONG TERM (AFTER 00Z FRIDAY)...UPPER LOW WILL CONTINUE DIGGING
SOUTH THURSDAY NIGHT...CLOSING OFF OVER SOCAL BY DAYBREAK FRIDAY.
12Z GLOBALS CONTINUE TO INDICATE A STRONG MOISTURE TAP FROM THE
TROPICAL EASTERN PACIFIC...AND ABSORPTION OF REMNANT ENERGY FROM
WHAT WAS HURRICANE ANDRES. THIS MOISTURE/ENERGY IS EXPECTED TO
REACH SOUTHEASTERN UTAH FRIDAY MORNING WITH SIGNIFICANT MOISTURE
ADVECTION WRAPPING NORTH AND WEST INTO THE SYSTEM FROM THERE
DURING THE DAY. WITH UPPER LOW POSITION ONCE AGAIN SETTING UP NEAR
STATIONARY OVER SOCAL...BOTH THE DOWNSTREAM JET AND DIFFLUENCE
ALOFT WILL AID LARGE SCALE FORCING ACROSS THE AREA FRIDAY THROUGH
SATURDAY. PWATS OF SOME 2 TO 3 DEVIATIONS ABOVE NORMAL CONTINUE
TO BE PORTRAYED BY NAEFS MEAN PW OWING TO THE RARITY OF MOISTURE
THIS DEEP THIS TIME OF YEAR. WITH CONTINUED RUN TO RUN CONSISTENCY
IN GLOBALS OPTED TO CONTINUE AN UPWARD TREND IN POPS...ESPECIALLY
ALONG THE MOUNTAIN SPINES AND POINTS EAST WHERE POTENTIALLY
SIGNIFICANT PRECIP IS LOOKING MORE LIKELY.

BOTH 12Z EC/GFS HINTING AT A SIGNIFICANT DRY SLOT DEVELOPING FROM
THE SOUTHWEST SATURDAY NIGHT INTO SUNDAY AS THE PARENT LOW
ELONGATES AND BECOMES MORE DIFFUSE...THEN STRETCHING FROM NORTHERN
NV SOUTHWEST INTO THE EASTERN PACIFIC. NOT OVERLY CONFIDENT YET ON
PLACEMENT OF THIS DRY SLOT ON SUNDAY...BUT BULK OF THE AREA SHOULD
BE EXPERIENCING A NET DRYING TREND WITH DIMINISHED FORCING...THIS OWING
TO MAINTENANCE OF SLIGHT CHANCE/CHANCE POPS IN LATEST FORECAST.

EC/GFS DIVERGE IN DETAIL THEREAFTER...SPECIFICALLY IN REGARDS TO
TRACK AND SIGNIFICANCE OF NOW HURRICANE BLANCA SPINNING IN THE
EASTERN PACIFIC. THOUGH INITIAL TRACK ONLY DIFFERS BY A FEW
HUNDRED MILES...GFS TAKES THE CIRCULATION NORTH ALONG THE GULF OF
CALIFORNIA /OVER WARM WATER/ MAINTAINING A STRONGER SYSTEM INTO
THE DESERT SOUTHWEST. EC TRACKS THIS WEST ALONG THE BAJA COAST
OVER THE MUCH COLDER WATERS OF THE EASTERN PACIFIC AND ALLOWS MUCH
OF THE ENERGY TO DISSIPATE QUITE RAPIDLY EARLY NEXT WEEK. OPTED TO
WAIT FOR A MORE CONSISTENT SOLUTION BEFORE GOING ONE WAY OR THE
OTHER REGARDING AREAL EXTENT OF AND POTENTIAL OF PRECIP EARLY
NEXT WEEK.

&&

.AVIATION...OPERATIONAL WEATHER CONCERNS WILL REMAIN MINIMAL AT
THE KSLC TERMINAL THROUGH THE OVERNIGHT HOURS. NORTHWEST WINDS ARE
EXPECTED TO SWITCH BACK TO THE SOUTHEAST BETWEEN 04-06Z AND WILL
REMAIN IN PLACE THROUGH THE NIGHT.

&&

.FIRE WEATHER...A FRONTAL BOUNDARY STALLED ACROSS CENTRAL UTAH WILL
RETREAT NORTHWARD JUST A BIT WEDNESDAY. TO THE SOUTH OF THIS
BOUNDARY A VERY DRY AIRMASS COUPLED WITH GUSTY SOUTH WINDS WILL
PREVAIL THROUGH THE REMAINDER OF THE AFTERNOON...AND REDEVELOP ONCE
AGAIN WEDNESDAY AFTERNOON. TO THE NORTH OF THIS BOUNDARY A COOLER
AIRMASS WILL RESIDE ACROSS NORTHERN UT...WHERE LINGERING MOISTURE
WILL MAINTAIN A SMALL CHANCE FOR SHOWERS AND THUNDERSTORMS. A DRIER
SOUTHERLY FLOW IS EXPECTED TO DEVELOP AREA-WIDE THURSDAY...BEFORE
MOISTURE SURGES NORTHWARD INTO THE REGION FRIDAY AND SATURDAY
RESULTING IN A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS CAPABLE OF
PRODUCING WETTING RAINS.

&&

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

$$

SEAMAN/MERRILL


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

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


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