Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 241023
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
423 AM MDT MON AUG 24 2015

.SYNOPSIS...A RIDGE OF HIGH PRESSURE OVER THE REGION WILL PERSIST
THROUGH THE EARLY PART OF THE WEEK. MOISTURE WILL SPREAD NORTHWARD
ACROSS THE AREA MIDWEEK...AS AN UPPER LEVEL DISTURBANCES ROTATES
ACROSS THE REGION.

&&

.SHORT TERM...MID LEVEL RIDGING ENCOMPASSING THE INTERMOUNTAIN
REGION AND DESERT SOUTHWEST IS FORECAST TO AMPLIFY
TODAY INDUCING A WARMING TREND ACROSS THE FORECAST AREA. A SLIGHT
DECREASE IN PRECIPITABLE WATER IS FORECAST TODAY...HOWEVER
LINGERING MOISTURE COUPLED WITH STRONG DAYTIME HEATING SHOULD
ALLOW FOR SCATTERED TERRAIN BASED CONVECTION THIS AFTERNOON FROM
THE UINTAS SOUTHWARD. LINGERING SMOKE WILL LIKELY CONTINUE TO
RESULT IN HAZY SKIES ACROSS AT LEAST NORTHERN AND CENTRAL UT. FOR
NOW HAVE LEFT AREAS OF SMOKE IN THE FORECAST...HOWEVER IF
CONDITIONS CONTINUE TO IMPROVE DAY SHIFT MAY BE ABLE TO REMOVE
SMOKE WORDING THIS AFTERNOON.

THE MID LEVEL RIDGE IS FORECAST TO SHIFT EAST AND BECOME CENTERED
OVER THE CENTRAL ROCKIES TUESDAY...ALLOWING A DEEP LAYER SOUTHERLY
FLOW TO DEVELOP ACROSS THE EASTERN GREAT BASIN. THIS WILL QUICKLY
ADVECT MOISTURE CURRENTLY IN PLACE ACROSS THE DESERT SOUTHWEST
NORTHWARD INTO THE FORECAST AREA...INITIALLY REACHING SOUTHERN UT
EARLY TUESDAY THEN EXPANDING NORTHWARD INTO NORTHERN UT BY TUESDAY
EVENING. INCREASED POPS A BIT ACROSS CENTRAL AND SOUTHERN UT
TUESDAY AFTERNOON...AND THEN AREAWIDE TUESDAY EVENING ACCORDINGLY.

THE MODELS CONTINUE TO SUGGEST A WELL DEFINED WAVE WILL LIFT
NORTHWARD THROUGH THE GREAT BASIN TUESDAY NIGHT INTO EARLY
WEDNESDAY ACCOMPANIED BY A SUBSTANTIAL SURGE IN MOISTURE.
UNFORTUNATELY THIS WAVE WILL BE LIFTING THROUGH THE REGION DURING
A DIURNALLY UNFAVORABLE TIME FOR DEEP CONVECTION...HOWEVER GIVEN
THE ABUNDANCE OF MOISTURE AND LIFT SHOULD SEE AN INCREASE IN
SHOWERS AND THUNDERSTORMS DURING THIS TIMEFRAME...AND HAVE AGAIN
TRENDED POPS UPWARD BY 10 TO 20 PERCENT ACROSS THE AREA DURING
THIS TIMEFRAME. WITH THE INCREASE IN MOISTURE AND CLOUD COVER
SHOULD ALSO SEE MUCH COOLER TEMPERATURES DURING THE DAY WEDNESDAY
ACROSS MOST AREAS.

IN THE WAKE OF THIS WAVE CONSIDERABLE SUBSIDENCE WILL GREATLY
LIMIT ANY ADDITIONAL CHANCE FOR CONVECTION LATE WEDNESDAY
AFTERNOON THROUGH WEDNESDAY EVENING. MID LEVEL RIDGING IS
FORECAST TO QUICKLY AMPLIFY ACROSS THE REGION THURSDAY BRINGING A
QUICK REBOUND IN TEMPERATURES. LIMITED MOISTURE COUPLED WITH LARGE
SCALE SUBSIDENCE WILL LIKELY LIMIT CONVECTIVE POTENTIAL TO THE
HIGHER TERRAIN DURING THE AFTERNOON AND EVENING HOURS.

.LONG TERM (AFTER 06Z FRIDAY)...THE GFS AND EC START TO DIVERGE ON
THE FORECAST SOLUTION THURSDAY WHICH LEADS TO A GREATER DISCREPANCY
BETWEEN THEM FROM FRIDAY FORWARD. WHILE THE EC MAINTAINS A CLOSED
CIRCULATION AT THE BASE OF THE EASTERN PACIFIC TROUGH THROUGH 06Z
SATURDAY THE GFS STARTS TO ABSORB IT NORTHWARD BACK INTO THE GENERAL
TROUGH BY 00Z FRIDAY...30 HRS EARLIER THEN THE EC. THIS IMPACTS THE
STRENGTH OF THE WINDS ON FRIDAY AND SATURDAY AS WELL AS STRENGTH OF
COLD FRONT WHICH THE EC BRINGS ACROSS THE CWA ON SUNDAY. THE GFS IS
WEAKER AND ABOUT 30-36 HRS SLOWER WITH THIS COLD FRONT. HAVE LEANED
THE FORECAST TOWARDS THE GFS SOLUTION BUT CONFIDENCE IS LOW. HAVE
REMOVED SOME POPS ACROSS NORTHERN UTAH FRIDAY EVEN THOUGH THE GFS
SHOWS QPF THERE ARE NO DYNAMICS TO SUPPORT QPF. OVER THE CENTRAL AND
SOUTHERN MOUNTAINS IT APPEARS THAT THERE WILL BE ENOUGH MOISTURE
REMAINING FOR ISOLATED THUNDERSTORMS FRIDAY AFTERNOON.

A DRY SOUTHWEST FLOW RETURNS FOR THE WEEKEND INTO EARLY NEXT WEEK.

&&

.FIRE WEATHER...LIMITED MOISTURE WILL KEEP CONVECTION MAINLY OVER
THE UINTAS AND THE CENTRAL AND SOUTHERN MOUNTAINS TODAY. A
DISTURBANCE MOVING UP FROM MEXICO WILL BRING MONSOONAL MOISTURE BACK
INTO SOUTHERN UTAH TUESDAY AND SPREAD IT ACROSS THE ENTIRE FIRE
WARNING AREA WEDNESDAY. LOCALIZED WETTING RAINS WILL LIKELY OCCUR
BUT THEN IN THE WAKE OF THIS DISTURBANCE A DRIER SOUTHWEST FLOW WILL
RETURN FOR THE END OF THE WEEK. WINDS WILL LIKELY INCREASE FRIDAY
AND SATURDAY...ESPECIALLY OVER WESTERN VALLEYS.

&&

.AVIATION...THE SLC TERMINAL WILL SEE SOUTHEAST WINDS THIS MORNING
UNTIL 19Z BEFORE SHIFTING TO THE NORTHWEST. THERE IS A 30 PERCENT
CHANCE THAT THE WIND SHIFT WILL HOLD OFF UNTIL 20Z. THERE ARE NO
OTHER METEOROLOGICAL CONCERNS FOR THE TAF PERIOD.

&&


&&

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

$$

SEAMAN/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)


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