Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 280954
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
354 AM MDT SUN SEP 28 2014

.SYNOPSIS...A COOL MOIST UPPER LOW WILL SLOWLY CROSS THE EASTERN
GREAT BASIN THROUGH MONDAY. ANOTHER WEAKER SYSTEM WILL CROSS
NORTHERN PORTIONS OF THE AREA TUESDAY NIGHT INTO WEDNESDAY. A
DRIER NORTHWEST FLOW WILL DEVELOP FOR THE LATTER PART OF THE WEEK.

&&

.SHORT TERM (THROUGH 12Z WEDNESDAY)...
WATER VAPOR LOOP SHOWS A DEEP CLOSED LOW OVER CENTRAL NEVADA.
AMDAR 400-250MB WIND OBSERVATIONS REVEAL A CYCLONIC 100-130KT JET
OVER THE WESTERN GREAT BASIN. GOES/GPS/RAP/00Z RAOB INDICATE THE
PRECIPITABLE WATER VALUE RANGES BETWEEN 0.25" SOUTHERN MOUNTAINS
TO 0.90"-1.20" NORTHERN AND EASTERN VALLEYS.

CANCELLED THE FLASH FLOOD WATCH. PRECIPITABLE WATER VALUES DROPPING
WITH COLDER AIR INFILTRATING SO NATURE OF THREAT WILL SHIFT AWAY
FROM HEAVY RAINFALL TO HIGH ELEVATION SNOWFALL AS THE COLD CORE
MOVES ACROSS UTAH TODAY AND TONIGHT NIGHT.

EARLY MORNING EASTERLY WINDS ALONG THE WASATCH FRONT ARE BEING
ENHNACED BY PRECIPITATION ON THE BACKSIDE OF THE MOUNTAINS...WITH
GUST VALUES EXCEEDING EVEN HIGH RESOLUTION MODEL FORECASTS. EXPECT
GUSTS TO DIMINISH AS THE PRECIPITATION SHIELD DISSIPATES.

ALSO MONITORING FOR POSSIBILITY OF FOG THIS MORNING WHERE SKIES ARE
CLEARING IN THE DRY SLOT ACROSS SOUTH CENTRAL AND SOUTHWEST UTAH.
SHOULD ANY DEVELOP WILL UPDATE THE FORECAST.

COOL AND UNSTABLE PATTERN CONTINUES THROUGH THE SHORT TERM PERIOD.
AS THE CLOSED LOW WEAKENS AND PASSES TO THE EAST LAST MONDAY...THE
LEFT EXIT REGION OF A PACIFIC JET ARRIVES TUESDAY MORNING BRINING
ANOTHER ROUND OF CLOUDINESS AND CHANCE FOR SHOWERS. THIS IS FOLLOWED
BY A COLD FRONT APPROACHING FROM THE NORTHWEST TUESDAY NIGHT.

SHORT RANGE ENSEMBLES SUGGEST THUNDER PROBABILITIES WANE AFTER
MONDAY AFTERNOON.

&&

.LONG TERM (AFTER 12Z WEDNESDAY)...
THE EC AND GFS ARE QUITE SIMILAR IN THE STRENGTH AND TIMING OF
THE TROUGH MOVING ACROSS THE GREAT BASIN WEDNESDAY. THEY BOTH
SHOULD GENERATE SOME LOCALLY BREEZY CONDITIONS IN AREAS FAVORED BY
NORTHWEST FLOW WEDNESDAY AFTERNOON. HOWEVER THE MODELS DIVERGE
FROM HERE. THE EC IS MORE IN LINE WITH THE GFS ENSEMBLE ON THE
SPEED OF THE TROUGH EXITING THE REGION. THEREFORE HAVE LEANED
TOWARD THE EC SOLUTION WHICH ALLOWS TEMPERATURES TO WARM 3 TO 4
DEGREES FASTER ON THURSDAY THAN THE GFS. THE EC REMAINS ABOUT THIS
3-4 DEGREES WARMER THROUGH SATURDAY BEFORE THE TRENDS OF THE TWO
MODELS REVERSE AND THE GFS BECOMES THE WARMER MODEL.

OTHER THAN A SLIGHT CHANCE OF SHOWERS ACROSS THE NORTH WEDNESDAY AND
WEDNESDAY NIGHT DRY CONDITIONS WITH A WARMING TREND IS EXPECTED
THURSDAY THROUGH SATURDAY WITH TEMPERATURES REACHING ABOUT 4 TO 8
DEGREES ABOVE NORMAL.

&&

.AVIATION...VFR CONDITIONS SHOULD PREVAIL AT THE SLC TERMINAL
THROUGH THE TAF PERIOD. CIGS WILL ALSO REMAIN ABOVE 7K FT AGL. WINDS
WILL PRIMARILY BE OUT OF THE SOUTHEAST THROUGH THIS MORNING THEN
SHIFT TO THE NORTHWEST THIS AFTERNOON AFTER 20Z. HOWEVER SCATTERED
SHOWERS IN THE VICINITY OF THE TERMINAL THIS AFTERNOON HAVE A 30
PERCENT CHANCE DISRUPTING THIS WIND PATTERN.

&&

.FIRE WEATHER...A COOL AND MOIST PATTERN REMAINS IN PLACE INTO MID
WEEK. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE
DURING THIS PERIOD...WITH HIGH ELEVATION SNOWFALL A THREAT AS
WELL.

&&

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

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...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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