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000
FXUS65 KSLC 181512
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
912 AM MDT SAT MAY 18 2013

.SYNOPSIS...A COOL MOIST UPPER TROUGH CENTERED OVER NORTHERN UTAH
THIS MORNING WILL MOVE EAST OF THE AREA THIS AFTERNOON. A COLDER
SYSTEM WILL CROSS THE REGION TONIGHT THROUGH MONDAY MORNING. HIGH
PRESSURE WILL BRIEFLY RETURN ON TUESDAY THEN SHIFT EAST WEDNESDAY.

&&

.DISCUSSION...UPPER TROUGH CONTINUES TO CROSS THE GREAT BASIN THIS
MORNING. A PRETTY IMPRESSIVE BAND OF HEAVY RAIN SHOWERS HAS BEEN
MOVING SLOWLY ACROSS NORTHERN UTAH ALL MORNING. THIS BAND EXTENDS
FROM NORTHERN UTAH COUNTY NORTH TO THE IDAHO BORDER. THE HEAVIEST
SHOWERS ARE LOCATED FROM OGDEN TO 25 MILES NORTHWEST OF BRIGHAM
CITY. THIS FEATURE HAS A RELATIVELY WELL DEFINED BACK EDGE AND
SHOULD MOVE EAST OF THE WASATCH FRONT IN THE NEXT HOUR OR TWO.
ISOLATED SHOWERS WILL THEN BECOME THE NORM. SOUTHWEST PORTION OF
THE STATE HAS LOST CLOUD COVER ALTHOUGH SOME SHOWERS STILL FALLING
OVER THE SOUTHERN MOUNTAINS. ISOLATED TO SCATTERED SHOWERS CAN
STILL BE EXPECTED TO THE SOUTH THROUGH THE DAY.

AIRMASS REMAINS SOMEWHAT MOIST AND MODERATELY UNSTABLE THROUGH THE
EVENING AND EXPECT WIDELY SCATTERED SHOWERS THROUGH THE EVENING
HOURS. A COLDER SECONDARY SHORT WAVE DROPS INTO THE NORTHERN GREAT
BASIN AFTER MIDNIGHT. NEWER MODEL HINTS THAT BEST THREAT FOR
PRECIPITATION WITH THIS FEATURE WILL BE CENTRAL UTAH. PREVIOUS
MODEL SUGGESTED NORTHERN UTAH. WILL HAVE TO WAIT FOR THE 12Z MODEL
RUN TO DECIDE WHETHER TO SHIFT FOCUS IN POP GRIDS OR LEAVE THEM
AS IS. IN EITHER CASE...SHOWERS WILL DEVELOP ACROSS MUCH OF THE
AREA SUNDAY AFTERNOON. SNOW LEVELS WILL BE A LITTLE LOWER WITH
THIS NEXT ROUND OF PRECIPITATION BUT STILL DO NOT EXPECT ANY
IMPACTS OVER ANY OF THE MAJOR PASSES. A THREAT OF PRECIPITATION
WILL LINGER OVER THE NORTHERN CWA INTO MONDAY UNDER WRAP AROUND
MOISTURE.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE SLC
TERMINAL THROUGH THE DAY. CEILINGS EXPECTED TO REMAIN AT OR ABOVE
5000 FEET AGL THROUGH 17Z. THERE IS A 30 PERCENT CHANCE THAT
HEAVIER SHOWERS COULD CAUSE BRIEF PERIODS OF MVFR CEILINGS AND
VISIBILITIES THROUGH 17Z. LIGHT NORTHWEST WINDS ARE EXPECTED TO
CONTINUE...BUT SHOWERS COULD CAUSE PERIODS OF ERRATIC WIND
DIRECTIONS THIS MORNING.

&&

.FIRE WEATHER...A SERIES OF STORM SYSTEMS WILL KEEP A COOL AND WET
PATTERN IN PLACE INTO MONDAY. THE FIRST STORM SYSTEM AFFECTING THE
REGION MAINLY THIS MORNING WILL BRING THE BEST CHANCE OF A WETTING
RAIN (SNOW ABOVE 8KFT) TO NORTHERN AND PORTIONS OF CENTRAL UTAH.

SHOWERS DIMINISH IN COVERAGE THIS AFTERNOON THROUGH TONIGHT. THEN
THE NEXT SYSTEM WILL BRING ANOTHER ROUND OF WETTING RAIN (SNOW ABOVE
7.5KFT) TO NORTHERN AND CENTRAL UTAH SUNDAY. A THIRD SYSTEM WILL
MAINLY AFFECT EASTERN UTAH MONDAY.

THE PATTERN SHIFTS AS A RIDGE BUILDS IN TUESDAY AND WEDNESDAY. A
WARMING AND DRYING TREND WILL TAKE PLACE WITH MOISTURE RECOVERIES AT
NIGHT BEGINNING TO LAG.

SOUTHWEST WINDS BEGIN TO DEVELOP TUESDAY NIGHT AS A LARGE STORM
SYSTEM DEVELOPS OVER THE PACIFIC NORTHWEST. THESE WINDS INCREASE AND
BECOME STRONG AND GUSTY WEDNESDAY THROUGH SATURDAY. AT THE SAME
TIME...DAYTIME HUMIDITY LEVELS BECOME VERY DRY...5-12% ACROSS MOST
VALLEYS...MAKING FOR CRITICAL FIRE WEATHER CONDITIONS IF ANY FUELS
ARE CRITICAL.

&&

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

&&

$$

PUBLIC/AVIATION...YOUNG
FIRE WEATHER......ROGOWSKI

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