076
FXUS02 KWBC 122100
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 PM EST THU JAN 12 2023
VALID 12Z SUN JAN 15 2023 - 12Z THU JAN 19 2023
...UNSETTLED AND ACTIVE PATTERN CONTINUES FOR WESTERN U.S. WITH
FOCUS ON CALIFORNIA ATMOSPHERIC RIVERS...
..OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
A SERIES OF SHORTWAVES WILL SPLIT FROM THEIR PARENT ALONG THE WEST
COAST AND SWING ACROSS THE MIDSECTION OF THE CONUS THROUGH NEXT
WEEK. A GENERAL MODEL BLEND CONSISTING OF THE 00Z EC/CMC/UKMET AND
06 GFS CAPTURED THE EARLY STAGES OF THE SYNOPTIC PATTERN
REASONABLY WELL. SOME MORE NOTABLE DIFFERENCES ARISE BY DAY 5,
NAMELY THE 06 GFS 500 HEIGHTS BECOME DISPLACED FROM THE 00Z
EC/CMC/UK SUITE BY AMPLIFYING AND SLOWING OVER THE SOUTHERN
CALIFORNIA COAST. THIS LEADS TO TIMING DIFFERENCES IN QPF
DOWNSTREAM IN THE SOUTHWEST, GREAT PLAINS AND MISSISSIPPI VALLEY
THROUGH THE END OF THE PERIOD. THEREFORE, LESS GFS WAS USED BEYOND
DAY 4. WE LEANED MORE TOWARD THE 00Z EC/ECE THROUGH DAY 7. THERE'S
UNCERTAINTY WITH RESPECT TO THE SYNOPTIC PROGRESSION AND QPF OF A
MIDWEEK STORM OVER THE GREAT PLAINS AND MISSISSIPPI VALLEY NEXT
WEEK, BUT THERE'S SIGNAL FOR HEAVY PRECIP TO DEVELOP SOMEWHERE IN
THAT REGION ON DAYS 6 AND 7.
..WEATHER/HAZARD HIGHLIGHTS
THE WEST WILL REMAIN ACTIVE AS A SERIES OF SHORTWAVES CONTINUES TO
DIRECT UNNEEDED ADDITIONAL HEAVY RAINFALL AND MOUNTAIN SNOWS
TOWARDS PARTICULARLY CALIFORNIA, BUT ALSO THE PACIFIC NORTHWEST.
THE FIRST IN THIS SERIES OF EXTENDED RANGE STORMS WILL ARRIVE ON
SATURDAY JUST BEFORE THE START OF THIS FORECAST PERIOD, AND THE
HEAVIEST OF THE PRECIPITATION SHOULD BE OVER BY SUNDAY AS THE
OVERALL UPPER SYSTEM MOVES INLAND. STILL, ANY LINGERING RAINFALL
OVER AN ALREADY VERY OVER-SATURATED CALIFORNIA MAY CONTINUE TO
WORSEN FLOODING OR DELAY IMPROVEMENT OF ONGOING ISSUES. RAIN AND
HIGHER ELEVATION SNOWS ARE POSSIBLE IN THE SOUTHWEST ON SUNDAY,
AND EVENTUALLY RETURN FLOW OUT OF THE GULF OF MEXICO MAY INCREASE
PRECIPITATION CHANCES INTO THE PLAINS/MIDWEST AS WELL EARLY NEXT
WEEK. THE NEXT IN THE SERIES SHOULD ARRIVE EARLY NEXT WEEK AGAIN
POSSIBLY EXACERBATING PROBLEMS ACROSS CALIFORNIA AS IT DELIVERS
MORE MOISTURE INTO THE REGION. HEAVY RAINFALL COULD DEVELOP OUT
INTO THE PLAINS-MISSISSIPPI VALLEY-MIDWEST AGAIN ALONG THE
ATTENDANT COLD FRONT NEXT WEDNESDAY, POSSIBLY HEAVY IF A STRONGER
STORM MANIFESTS. THERE COULD BE A CHANCE FOR SOME SNOW/ICE TOO IN
THE NORTHERN PERIPHERY OF THE STORM, AMOUNTS AGAIN HIGHLY
DEPENDENT ON STORM STRENGTH.
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 15 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
HAZARDS:
- HEAVY RAIN ACROSS PORTIONS OF THE PACIFIC NORTHWEST, TUE, JAN 17.
- HEAVY RAIN ACROSS PORTIONS OF CALIFORNIA, SUN-MON, JAN 15-JAN 16.
- HEAVY RAIN ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY, THE
LOWER MISSISSIPPI VALLEY, THE
OHIO VALLEY, AND THE TENNESSEE VALLEY, WED, JAN 18.
- HEAVY SNOW ACROSS PORTIONS OF CALIFORNIA, THE PACIFIC NORTHWEST,
AND THE NORTHERN GREAT BASIN,
TUE-WED, JAN 17-JAN 18.
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL/SOUTHERN ROCKIES, THE
CENTRAL GREAT BASIN, THE
SOUTHWEST, AND CALIFORNIA, SUN-WED, JAN 15-JAN 18.
- HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN/CENTRAL ROCKIES, THE
GREAT BASIN, AND THE SOUTHWEST,
SUN-TUE, JAN 15-JAN 17.
- HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN INTERMOUNTAIN REGION,
THU, JAN 19.
- HIGH WINDS ACROSS PORTIONS OF THE SOUTHERN ROCKIES, THE SOUTHERN
PLAINS, AND THE SOUTHWEST,
SUN-MON, JAN 15-JAN 16.
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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