Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 240356
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
956 PM MDT THU APR 23 2015

.SYNOPSIS...AN UNSETTLED WEATHER PATTERN WILL REMAIN OVER THE
FORECAST AREA THROUGH FRIDAY. A COLD AND ENERGETIC PACIFIC STORM
SYSTEM WILL IMPACT THE REGION THIS WEEKEND. HIGH PRESSURE WILL
RETURN FOR EARLY NEXT WEEK.


&&

.SHORT TERM (THROUGH 00Z MONDAY)...ORGANIZED CONVECTION THAT
FORMED ACROSS NORTHWEST IN VICINITY TO THE SURFACE TROUGH AND
ALONG THE NEAR 700MB BAROCLINIC ZONE THIS AFTERNOON IS WINDING
DOWN AT MID-EVENING. LOSS OF DAYTIME HEATING AND THE EXIT OF THE
SHORTWAVE OVER THE NORTHERN ROCKIES SHOULD BRING AN END TO ALL BUT
A FEW LIGHT SHOWERS OVERNIGHT.

CONVECTION SHOULD ONCE AGAIN BUBBLE UP ACROSS THE HIGHER TERRAIN
BEGINNING MID TO LATE FRIDAY MORNING. THIS CONVECTION WILL BECOME
BETTER ORGANIZED AS THE SURFACE FRONT ASSOCIATED THE NEXT MID-
LEVEL TROUGH MOVES ACROSS NORTHWEST UTAH FRIDAY AFTERNOON. THE
MID-LEVEL TROUGH WILL MOVE EAST-NORTHEAST ACROSS NORTHERN
UTAH/EASTERN IDAHO DURING PEAK HEATING LATE IN THE AFTERNOON
THROUGH EARLY EVENING. PEAK INSTABILITY AND DYNAMIC LIFT SHOULD BE
MORE THAN SUFFICIENT FOR CONVECTION ACROSS MAINLY NORTHERN
UTAH/SOUTHWEST WYOMING. CENTRAL/SOUTHERN ARE NOT LIKELY TO GET
SHUT OUT FROM CONVECTION...THOUGH WITH WEAK DYNAMIC LIFT THE AREAL
COVERAGE AND INTENSITY OF SHOWERS/STORMS IS LIKELY TO BE LESS THAN
ACROSS THE NORTH.

THE LATTER HALF OF THE UPCOMING WEEKEND STILL ON TRACK FOR MUCH
COLDER TEMPS AND WIDESPREAD FOR SATURDAY NIGHT/SUNDAY. THE UPPER
LOW CURRENTLY ALONG THE SOUTHERN BRITCOL AND PACIFIC NORTHWEST
COAST WILL ELONGATE TO THE SOUTHEAST INTO THE GREAT BASIN THIS
WEEKEND. THIS FEATURE WILL EVENTUALLY EVOLVE INTO A NEW CLOSED
LOW OVER THE SOUTHERN END OF THE ELONGATED TROUGH NEAR THE FOUR
CORNERS LATE IN THE WEEKEND. THE TREND IN THE GFS/ECMWF OF LATE
HAS BEEN TO REDUCED THE AMOUNT OF COLD AIR MOVING IN THE STATE AND
DEVELOPING THE NEW UPPER LOW LATER AND FURTHER SOUTH. THE RESULT
OF THIS WILL BE TO REDUCE THE AMOUNT OF PRECIP FOR THE NORTH...BUT
KEEP A SUBSTANTIAL AMOUNT FOR THE SOUTH CLOSE TO THE NEWLY
DEVELOPED LOW. HIGH POPS AND STILL RESPECTABLE PRECIP AMOUNTS ARE
LIKELY THROUGH THE WEEKEND.

&&

.PREVIOUS LONG TERM (AFTER 00Z MONDAY)...BOTH THE EC AND GFS SHOW
SOME 700 MB MOISTURE AND PRECIP REMAINING OVER THE EASTERN PORTION
OF THE CWA THROUGH SUNDAY EVENING AND INTO MONDAY OVER THE UINTAS
AND SOUTHWEST WYOMING. THE 700 MB WINDS WILL ARE FORECAST TO BE
NORTHWEST TO NORTH AT 20-35 KTS ACROSS THE MOST OF THE CWA SUNDAY
EVENING WHICH SHOULD MAKE FOR SOME BREEZY CONDITIONS WITH POSSIBLY
LOCALLY WINDY CONDITIONS IN THE FAVORABLE DOWNSLOPE REGIONS IN
CASTLE COUNTRY AND IN WASHINGTON COUNTY.

THE SURFACE HIGH BUILDS IN MONDAY WITH A MODEST SURFACE GRADIENT
REMAINING OVER THE SOUTHERN AND EASTERN PORTIONS OF THE CWA.
TEMPERATURES WILL WARM ABOUT 4-6 DEGREES CELSIUS AT 700 MB FROM LATE
SUNDAY TO LATE MONDAY WITH ANOTHER 3-4 DEGREES FROM MONDAY TO
TUESDAY...SO THE WARMING TREND WILL BE RAPID AND CONTINUE INTO
MIDWEEK. WARMEST TEMPERATURES OF THE SEASON EXPECTED WEDNESDAY AND
THURSDAY.

AFTER A SLIGHT CHANCE OF PRECIP OVER THE NORTHERN MOUNTAINS THURSDAY
EVENING AS MODELS STARTING TO HINT AT A TROUGH APPROACHING WITH THE
EC MORE PROGRESSIVE AND WEAKER THAN THE GFS.

&&

.AVIATION...CONVECTION ACROSS NORTHERN UTAH WILL CONTINUE TO DECAY
THROUGH THE BALANCE OF THE EVENING. THE EVENING CONVECTION
CONCENTRATED TO THE WEST AND NORTH OF THE TERMINAL HAS PRODUCED
THE CURRENT NORTHWEST OUTFLOW WINDS THESE WINDS MAY STILL PRODUCE
GUSTS BETWEEN 20 AND 25 KNOTS THROUGH 05Z...THEN TURN AROUND TO A
MORE TYPICAL SOUTHEAST DRAINAGE WINDS AFTER 07Z. CEILINGS AROUND
10 TO 12 KFT WILL GENERALLY DISSIPATE AFTER 06Z.

&&

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

$$

PUBLIC...CONGER
AVIATION...

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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