000
FXUS65 KSLC 240941
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
341 AM MDT FRI MAY 24 2013

.SYNOPSIS...A COLD FRONT OVER THE SOUTHEAST CORNER OF UTAH WILL
DISSIPATE TODAY...SETTING THE STAGE FOR A RETURN TO A WARM AND DRY
SOUTHWESTERLY FLOW FOR THE WEEKEND.

&&

.DISCUSSION...A SECONDARY SURGE OF COLD AIR PUSHED A COLD FRONT TO
THE SOUTHEAST CORNER OF UTAH OVERNIGHT.  THIS FRONT WILL DECAY TODAY
AND A WARM AND DRY SOUTHWEST FLOW WILL DEVELOP...THEN PERSIST
THROUGH THE WEEKEND.

CHALLENGE OF LATE HAS BEEN TIMING OF WEAK COLD AIR SURGES AS WEST
COAST TROUGH PERSISTS AND WEAK DISTURBANCES IN SOUTHWEST FLOW
OCCASIONALLY PUSH WEAK COLD FRONTS INTO FORECAST AREA.  TOO SOME
DEGREE...SAME CHALLENGE EXISTS THIS PACKAGE...THOUGH VERY FEW
CONCERNS EXIST UNTIL AT LEAST LATE IN THE WEEKEND...WHEN NAM
SUGGESTS NEXT FRONTAL PUSH INTO NORTHERN UTAH IN ASSOCIATION WITH A
MID LEVEL DISTURBANCE.  GFS AND ECMWF ARE IN AGREEMENT WITH A SLOWER
SOLUTION...BRINGING COLD FRONT ONLY INTO NORTHWEST CORNER OF UTAH ON
MONDAY...BEFORE IT RETREATS.  EVEN NAM SUGGESTS LITTLE IN THE WAY OF
MOISTURE WITH THE SYSTEM FOR LATE IN THE WEEKEND.  CONSIDERING
ABOVE...EXISTING SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS
NORTHWEST CORNER OF UTAH AND HIGH TERRAIN OF WASATCH AND UINTAS
LOOKS GOOD.  OTHERWISE...A MILD AND DRY MEMORIAL DAY WEEKEND IS ON
TAP.

PRIMARY CONCERN THIS FORECAST PACKAGE IS EASTWARD PROGRESSION AND
DEPTH OF WEST COAST TROUGH.  GFS SUGGESTS A NEGATIVE TILT TROUGH
MOVING THROUGH REGION...WITH A STRONG 120KT 300 MB JET.  ECMWF
CONTINUES TO INDICATE A CLOSED LOW FORMING OVER ARIZONA...BEFORE
EJECTING EAST.  NOT A SINGLE GFS ENSEMBLE RUN INDICATES A CLOSED
LOW...THOUGH SIGNIFICANT UPPER JET ENERGY DOES FAVOR SOME POTENTIAL.
IN ANY CASE...EXPECTED A DEEP LOW PRESSURE TROUGH OVER THE
INTERMOUNTAIN REGION FROM LATE TUESDAY INTO THURSDAY...WITH
INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS.  WEDNESDAY APPEARS
TO BE MOST FAVORABLE FOR PRECIPITATION AND HAVE BOOSTED POPS
ACCORDINGLY.

RIDGING ALOFT WILL BUILD OVER THE REGION ON FRIDAY WITH JUST SOME
RESIDUAL SHOWERS AND THUNDERSTORMS OVER HIGHER TERRAIN AREAS.

&&

.AVIATION...LIGHT AND VARIABLE SURFACE WINDS EARLY THIS MORNING AT
THE KSLC TERMINAL WILL BECOME A LIGHT SOUTHEAST FLOW BY 11-12Z.
LIGHT SOUTHEAST WINDS WILL THEN HOLD THROUGH THE MORNING BEFORE
BECOMING NORTHWEST BETWEEN 18-20Z. OUTSIDE OF THESE WIND SWITCHES
OPERATIONAL WEATHER CONCERNS WILL REMAIN MINIMAL AT THE KSLC
TERMINAL WITH VFR CONDITIONS HOLDING UNDER LARGELY CLEAR SKIES THIS
VALID TAF PERIOD.

&&

.FIRE WEATHER...SIMILAR TO YESTERDAY MORNING THE DRY COLD FRONT HAS
SETTLED BACK INTO SOUTH CENTRAL PORTIONS OF THE DISTRICT THIS
MORNING. THIS FRONT IS NOW STALLING AND WILL GRADUALLY FIZZLE TODAY
AS A STRENGTHENING SOUTHWESTERLY FLOW BEGINS TO DOMINATE LOCAL
WEATHER. WITH THIS...BONE DRY AND LOCALLY GUSTY CONDITIONS WILL
CONTINUE ACROSS THE SOUTH AND EAST TODAY AND ACROSS MOST ALL AREAS
TOMORROW AS YET ANOTHER WARMING TREND ENSUES DISTRICT WIDE HEADING
INTO THE WEEKEND. THE WINDS AND LOW HUMIDITIES HAVE THE POTENTIAL TO
CREATE LOCALLY HAZARDOUS FIRE WEATHER CONDITIONS IF FUELS ARE/WERE
CRITICAL...BUT NOT TO THE EXTENT THAT WE SAW ON THURSDAY.

A PACIFIC STORM SYSTEM WILL BEGIN TO MOVE INTO THE AREA SUNDAY
BRINGING WITH IT AN INITIAL ROUND OF HIGH BASED THUNDERSTORMS
ACROSS THE NORTHERN TERRAIN. SHOWER AND THUNDERSTORM ACTIVITY
WILL INCREASE THEREAFTER PEAKING MID WEEK WITH HIGHER CHANCES OF
WETTING RAINS AT THAT TIME.

&&

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

&&

$$

AVIATION/FIRE WEATHER...MERRILL
PUBLIC...BARJENBRUCH

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VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)