941
FXUS02 KWBC 111901
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
201 PM EST WED JAN 11 2023
VALID 12Z SAT JAN 14 2023 - 12Z WED JAN 18 2023
...UNSETTLED AND ACTIVE PATTERN CONTINUES FOR WESTERN U.S. WITH
FOCUS ON CALIFORNIA ATMOSPHERIC RIVERS...
..OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
A GENERAL MODEL BLEND CONSISTING OF THE DETERMINISTIC 00Z
EC/CMC/UKMET AND 06Z GFS WAS UTILIZED THROUGH DAY 5. THE 00Z ECE
WAS INTRODUCED ON DAY 5 AND CONTINUED THROUGH DAY 7 WITH STEADY
INCREASES THROUGH THE END OF THE PERIOD. THE 06Z GEFS AND 00Z CMCE
WERE INTRODUCED ON DAY 6 AND CONTINUED THROUGH DAY 7 WITH
INCREASED WEIGHTING. THE 13Z NBM TRENDED DRIER OVERALL ALONG THE
WEST COAST THROUGHOUT THE MEDIUM RANGE PERIOD. THERE'S REASONABLE
AGREEMENT WITH RESPECT TO THE QPF IN NORTHERN/CENTRAL CALIFORNIA
ON DAY 5, BUT THE LAST FEW RUNS OF THE EC HAVE THROWN A WRENCH IN
ANY PLANS FOR AN UPGRADE TO THE CURRENT MARGINAL RISK ERO FOR THAT
AREA. THIS CAN BE REEVALUATED IF SUBSEQUENT RUNS OF THE EC TREND
CLOSER/FASTER TO THE OTHER GUIDANCE. SOME MINOR TARGETED CHANGES
WERE MADE TO THE QPF ALONG THE WEST COAST TO KEEP OUR LATEST
GUIDANCE FROM STRAYING TOO FAR FROM TO CONTINUITY.
..WEATHER/HAZARD HIGHLIGHTS
UNSETTLED AND ACTIVE WEATHER IS EXPECTED TO CONTINUE ACROSS
PORTIONS OF THE WEST AS A SERIES OF ATMOSPHERIC RIVERS MOVE
ONSHORE. THE FIRST IN THIS SERIES OF EXTENDED RANGE STORMS WILL
ARRIVE THIS WEEKEND, AND IS EXPECTED TO BRING ANOTHER ROUND OF
WIDESPREAD HEAVY RAIN ACROSS NORTHERN AND COASTAL CALIFORNIA WITH
HEAVY SNOWFALL INTO THE SIERRA MOUNTAINS AS WELL. WORSENING
FLOODING OR DELAYED IMPROVEMENT OF ONGOING ISSUES IS POSSIBLE
ACROSS THIS VERY OVER-SATURATED COASTAL CENTRAL TO SOUTHERN
CALIFORNIA. AS THE ENERGY MOVES INLAND ON SUNDAY, RAIN AND HIGHER
ELEVATION SNOWS ARE POSSIBLE IN THE SOUTHWEST, AND EVENTUALLY
RETURN FLOW OUT OF THE GULF OF MEXICO MAY INCREASE PRECIPITATION
CHANCES INTO THE PLAINS/MIDWEST AS WELL. AN ALMOST CONSTANT FETCH
OF ONSHORE MOISTURE INTO THE NORTHWEST AND PARTS OF THE CALIFORNIA
THROUGH THE PERIOD WILL KEEP RAINFALL, THOUGH LESS INTENSE, IN THE
FORECAST EARLY NEXT WEEK BEFORE ANOTHER POSSIBLE HEAVIER STORM
ARRIVES AROUND NEXT TUESDAY. IN THE EAST, PRECIPITATION AHEAD OF
THE TROUGH SHOULD BE WELL OFF THE COAST BY THIS WEEKEND, EXCEPT
FOR SOME POSSIBLY LIGHT WRAP BACK SNOWS ACROSS NORTHERN NEW
ENGLAND WHICH IS DEPENDENT ON PROXIMITY OF SECONDARY LOW
DEVELOPMENT TO THE COAST.
ABOVE NORMAL TEMPERATURES WILL MOVE EAST WITH TIME FROM THE
CENTRAL U.S. THIS WEEKEND INTO THE MIDWEST AND EVENTUALLY THE EAST
EARLY NEXT WEEK. THE GREATEST ANOMALIES SHOULD FOCUS ACROSS THE
DEEP SOUTH INTO THE MIDWEST WITH DAYTIME HIGHS 10 TO 20 DEGREES F
ABOVE NORMAL. EVEN MORE IMPRESSIVE WILL BE THE VERY WARM NIGHTTIME
LOWS, WITH READINGS 20 TO 25 DEGREES F ABOVE NORMAL GENERALLY
ACROSS THE SAME REGION FROM SUNDAY ONWARD. DAYTIME HIGHS ACROSS
THE WEST AND SOUTHWEST SHOULD BE NEAR OR BELOW NORMAL AMIDST
PLENTY OF CLOUDS AND RAINY CONDITIONS.
KEBEDE/SANTORELLI
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE
AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
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