742
FXUS02 KWBC 201901
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EST FRI JAN 20 2023
VALID 12Z MON JAN 23 2023 - 12Z FRI JAN 27 2023
...HEAVY SNOW THREAT FOR THE INTERIOR NORTHEAST WITH AN EXITING
STORM MONDAY...
...SECOND STORM TO SPREAD A HEAVY RAIN/SEVERE WEATHER THREAT TO
THE SOUTH EARLY NEXT WEEK, WORKING UP THE EASTERN SEABOARD MIDWEEK
ALONG WITH A HEAVY SNOW THREAT FROM THE CENTRAL ROCKIES/PLAINS
THROUGH THE INTERIOR NORTHEAST...
..SYNOPTIC OVERVIEW
THE WEATHER PATTERN WILL REMAIN STORMY BUT PROGRESSIVE ACROSS MUCH
OF THE NATION GOING INTO NEXT WEEK WITH TWO WELL DEFINED LOW
PRESSURE SYSTEMS OF INTEREST. THE FIRST WILL BE AFFECTING THE
NORTHEAST U.S. GOING THROUGH MONDAY AND THEN EXITING INTO
SOUTHEAST CANADA BY TUESDAY, WITH COASTAL RAIN AND INTERIOR SNOW.
MEANWHILE, THE NEXT CLOSED/DEEP SYSTEM WILL DIG ROBUSTLY OVER THE
SOUTHWEST INTO MONDAY THEN EJECT ACROSS THE SOUTH-CENTRAL U.S.
EARLY IN NEXT WEEK, WITH A SUBSEQUENT TRACK IN A GENERAL
NORTHEASTERLY DIRECTION ACROSS THE OHIO VALLEY AND THEN THE GREAT
LAKES BY WEDNESDAY AND INTO THURSDAY. A BUILDING WEST
COAST/WESTERN CANADA UPPER RIDGE AS A +PNA PATTERN WILL THEN
HERALD A RETURN TO COLDER CONDITIONS FROM THE WEST TO ACROSS MUCH
OF THE CENTRAL AND EASTERN U.S. AS AMPLIFIED UPPER TROUGHING WORKS
DEVELOPS DOWNSTREAM.
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST GUIDANCE SOLUTIONS REMAIN BETTER CLUSTERED THAN NORMAL WITH
THE OVERALL SYNOPTIC SCALE DEPICTION ACROSS THE CONTINENTAL U.S.
THROUGH THE MIDDLE OF NEXT WEEK. ACCORDINGLY PREFER A COMPOSITE
BLEND OF THE GFS/ECMWF/UKMET/CMC FOR MAX DETAILS CONSISTENT WITH A
PATTERN WITH HIGH PREDICTABILITY. ADDED INTO THE MIX SOME
GEFS/ECMWF ENSEMBLE INPUT FOR LONGER TIME FRAMES TO ACCOUNT FOR
INCREASING, BUT GENERALLY MANAGEABLE, FORECAST SPREAD. WPC PRODUCT
CONTINUITY IS GOOD.
..WEATHER/HAZARD HIGHLIGHTS
THE FIRST STORM SYSTEM OF NOTE WILL BE AN INTENSIFYING SURFACE LOW
NEAR EASTERN NEW ENGLAND ON MONDAY MORNING THAT WILL QUICKLY LIFT
NORTHWARD ACROSS THE SOUTHEASTERN PROVINCES OF CANADA BY TUESDAY.
THIS IS EXPECTED TO PRODUCE A SWATH OF PLOWABLE SNOWS FROM THE
ADIRONDACKS TO MAINE, AND A WIND-DRIVEN RAIN CLOSER TO THE COAST
WITH GUSTS OVER 40 MPH AT TIMES. HIGH PRESSURE WILL BRIEFLY
SETTLE IN ACROSS THE EASTERN U.S. BEFORE THE NEXT DEEPENED LOW
PRESSURE SYSTEM ARRIVES. THIS IS FORECAST TO WORK OUT FROM A
HIGHLY UNSETTLED SOUTHWEST/ROCKIES MONDAY AND DEVELOP OVER THE
SOUTHERN PLAINS/GULF COAST REGION INTO TUESDAY BEFORE TRACKING
NORTHEAST ACROSS THE OHIO VALLEY AND THEN THE GREAT LAKES THROUGH
NEXT MID WEEK, REACHING THE NORTHEAST U.S. BY THURSDAY. THE BEST
HEAVY RAINFALL POTENTIAL EXISTS FROM THE SOUTH/SOUTHEAST AND
APPALACHIANS TO UP THE EASTERN SEABOARD, WHILE AN AXIS OF WINTRY
WEATHER SPREADS FROM THE CENTRAL PLAINS NORTHEASTWARD INTO THE
INTERIOR NORTHEAST. ACROSS THE WEST, RAIN AND MOUNTAIN SNOW OF
MOSTLY LIGHT TO MODERATE AMOUNTS SHOULD EXTEND SOUTH-SOUTHEAST
ACROSS THE ROCKIES AND NEARBY AREAS WITH UPPER TROUGH/LOW SUPPORT
AND LOWER LEVEL UPSLOPE FLOW.
TEMPERATURES ARE EXPECTED TO GENERALLY BE ON THE ORDER OF 5 TO 15
DEGREES BELOW AVERAGE FROM THE INTERMOUNTAIN WEST TO THE WESTERN
HIGH PLAINS FOR EARLY IN THE WEEK, AND SLIGHTLY ABOVE AVERAGE
ACROSS MOST OF THE EASTERN U.S. BY THE END OF THE WEEK, MOST
AREAS ACROSS THE NATION SHOULD BE BETWEEN AVERAGE AND 10 DEGREES
BELOW AVERAGE AS BROAD UPPER TROUGH AND CYCLONIC FLOW ALOFT KEEP
ANY ANOMALOUS WARMTH AWAY.
HAMRICK/SCHICHTEL
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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