460
FXUS65 KSLC 191011
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
411 AM MDT TUE MAR 19 2019
SYNOPSIS
THE NEXT STORM SYSTEM WILL ARRIVE MIDWEEK, WITH IMPACTS PRIMARILY
ACROSS THE SOUTHERN AND CENTRAL PORTIONS OF THE FORECAST AREA.
ANOTHER STORM SYSTEM WILL FOLLOW BY LATE THIS WEEKEND.
SHORT TERM (THROUGH 00Z SATURDAY)
SEVERAL DISTURBANCES WILL COMBINE TO OUR WEST TODAY AND TONIGHT,
WITH A SPRING STORM EVENTUALLY EVOLVING. ON APPROACH TODAY AND
TONIGHT, A BUILDING NORTHEASTERLY PRESSURE GRADIENT WILL COMBINE
WITH PRESSURE FALLS TO THE WEST TO SUPPORT THE DEVELOPMENT OF
EAST-NORTHEAST FLOW ACROSS THE STATE. WINDS MAY BE LOCALLY GUSTY
ALONG THE WASATCH FRONT AND DIXIE LATE TONIGHT INTO TOMORROW
NIGHT.
WITH HEIGHT FALLS AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE
APPROACH OF THIS SYSTEM REACHING UTAH LATE TOMORROW AND CONTINUING
INTO FRIDAY, PRECIPITATION CHANCES INCREASE SIGNIFICANTLY,
ESPECIALLY FOR SOUTHERN AND CENTRAL UTAH. THERE IS SUFFICIENT
INSTABILITY AND LAPSE RATES TO MENTION THE THREAT OF THUNDER
DURING THIS PERIOD.
SNOW LEVELS LOOK TO REMAIN ABOVE 6KFT FOR THE AREAS WITH THE BULK
OF THE PRECIPITATION. SOUTHERN AND CENTRAL MOUNTAINS MAY SEE
LOCALLY SIGNIFICANT ACCUMULATIONS AIDED BY SOUTH-SOUTHEAST
OROGRAPHIC ENHANCEMENT TOMORROW NIGHT. MOST VALLEYS LOOK TO
REMAIN RAIN OR A RAIN/SNOW MIX THROUGH THE SHORT TERM PERIOD. BEST
BET FOR VALLEY SNOW ACCUMULATIONS WILL BE NORTH OF HANKSVILLE
INTO PRICE AND ACROSS THE WESTERN UINTA BASIN.
GIVEN THE CONVECTIVE NATURE OF PRECIPITATION, LCL LOWERING TO NEAR
850MB, AND WARM CLOUD DEPTH INCREASING TO 3-4KFT, LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE ACROSS SOUTHERN VALLEYS, ESPECIALLY LATE
TOMORROW AFTERNOON INTO THURSDAY MORNING. THIS IS COINCIDENT WITH
ANOMALOUSLY HIGH PRECIPITABLE WATER VALUES AS WELL.
FRIDAY IS A TRANSITION DAY WITH THE TROUGH MAKING ITS WAY TO OUR
NORTHEAST, ENCOURAGING BUILDING HEIGHTS AND WARMING ALOFT FROM
SOUTHWEST TO NORTHEAST DURING THE AFTERNOON AND EVENING.
DAY SHIFT MAY END UP LOOKING AT WINTER WEATHER ADVISORIES AND THE
FLOOD THREAT EVEN FURTHER AS THE EVENT NEARS.
LONG TERM (AFTER 00Z SATURDAY)
ACTIVE AND UNSETTLED WEATHER IS EXPECTED TO CONTINUE THROUGH THE
FIRST HALF OF THE LONG TERM PERIOD PRIOR TO A PERIOD RIDGING
EARLY/MID NEXT WEEK. IN LARGE GLOBALS CONTINUE TO ADVERTISE A
RELATIVE BREAK LATER FRIDAY NIGHT THROUGH SATURDAY MORNING AS THE
PREVIOUS LATE WEEK TROUGH LIFTS DOWNSTREAM AND NORTHEAST OF THE
AREA, WHILE THE NEXT AMPLIFIES A BIT UPSTREAM ALONG THE NORCAL
COAST. THE PROGRESSIVE NATURE OF THE PATTERN HOWEVER LOOKS TO SEE
A DETERIORATION OF TRANQUIL CONDITIONS BY LATER SATURDAY AFTERNOON
AS THIS UPSTREAM TROUGH MOVES INTO AND ACROSS THE EASTERN GREAT
BASIN.
DETERMINISTIC RUNS IN GLOBALS CONTINUE TO SHOW SPREAD IN
AMPLITUDE/EVOLUTION OF THIS TROUGH, WITH THE EC DEEPER AND THE GFS
MORE SHEARED AND OF LOWER AMPLITUDE...DIFFERENCES RELATING TO TIMING
AND STRENGTH OF RIDGE AMPLIFICATION UPSTREAM OF THIS TROUGH. THIS
SAID, ALL SIGNALS POINT TO INCREASED AREAL COVERAGE OF SHOWERS (MTN
SNOW/VALLEY RAIN) FROM WEST-EAST LATE SATURDAY THROUGH MUCH OF
SUNDAY, WITH EVENTUAL DRYING FROM SW-NE BY SUNDAY NIGHT AS THE RIDGE
BECOMES INCREASINGLY MORE DOMINANT LOCALLY. DYNAMICALLY SPEAKING
THIS TROUGH IS NOT ADVERTISED TO BE OVERLY IMPRESSIVE, BUT BREADTH
OF MOISTURE AND INCREASING LIKELIHOOD OF CONVECTION SHOULD SUPPORT
MODEST PRECIP FOR SOME AREAS (ESPECIALLY NORTH).
AS MENTIONED, THE RIDGE WILL CONTINUE TO BUILD INTO THE REGION
THROUGH EARLY NEXT WEEK PROVIDING DRY/TRANQUIL CONDITIONS AND
WARMING TREND TEMPS.
AVIATION
OPERATIONAL WEATHER CONCERNS ARE EXPECTED TO REMAIN MINIMAL AT
THE KSLC TERMINAL TODAY, WITH GENERALLY LIGHT AND VARIABLE WINDS
THIS MORNING BECOMING NORTHERLY AROUND 18Z. A 30% CHANCE EXISTS
THAT THE NORTHWESTERLY WINDS WILL BEGIN TO PREVAIL AS EARLY AS 16Z
HOWEVER.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
SHORT TERM...10
LONG TERM/AVIATION...MERRILL
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP
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