814
FXUS02 KWBC 051905
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
204 PM EST FRI JAN 05 2024
VALID 12Z MON JAN 08 2024 - 12Z FRI JAN 12 2024
...POWERHOUSE STORM TO TRACK FROM THE SOUTHERN PLAINS TO THE GREAT
LAKES/NORTHEAST MONDAY-WEDNESDAY OFFERS WIDESPREAD THREATS FOR
EXCESSIVE RAIN/RUNOFF, HEAVY SNOW/WIND AND SEVERE THUNDERSTORMS...
...DYNAMIC SYSTEMS TO IMPACT AN UNSETTLED/WINTRY WEST AS ARCTIC
AIR DIGS INTO THE NORTH-CENTRAL U.S. MID-LATER NEXT WEEK...
..OVERVIEW
DEEP SURFACE CYCLOGENESIS IS EXPECTED ACROSS THE SOUTH-CENTRAL
PLAINS BY MONDAY AS A MAJOR UPPER TROUGH SHIFTS OUT FROM THE WEST,
WITH IMPRESSIVE MOISTURE AND INSTABILITY RETURNING TO FUEL
WIDESPREAD HEAVY RAINFALL/CONVECTION AND RUNOFF/WIND ISSUES ACROSS
THE SOUTH-CENTRAL TO EASTERN U.S. THROUGH NEXT MIDWEEK. TO THE
NORTH OF THE DEEP LOW'S TRACK, THERE IS ALSO A SIGNIFICANT
SNOW/ICE THREAT FROM THE CENTRAL PLAINS TO THE MIDWEST/GREAT LAKES
AND NORTHEAST MONDAY-WEDNESDAY/THURSDAY, ALONG WITH STRONG AND
GUSTY WINDS. ADDITIONAL DYNAMIC SYSTEMS IN THE SERIES LOOK TO MOVE
INTO THE PACIFIC NORTHWEST EARLY NEXT WEEK BEFORE DIGGING ACROSS
THE WEST INTO MID-LATE NEXT WEEK JUST AS AN FRIGID ARCTIC AIRMASS
SLAMS SOUTHWARD FROM CANADA INTO THE NORTH-CENTRAL U.S..
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL GUIDANCE SUITE CONTINUES TO OFFER A GOOD OVERALL
DEPICTION OF THE SYNOPTIC SCALE WEATHER PATTERN FOR THE FIRST HALF
OF NEXT WEEK INCLUDING THE EVOLUTION OF THE MAJOR LOW PRESSURE
SYSTEM OVER THE PLAINS AND GREAT LAKES/NORTHEAST. A
MULTI-DETERMINISTIC COMPOSITE MODEL BLEND OF WELL CLUSTERED
GUIDANCE FROM THE GFS/ECMWF/UKMET/CANADIAN ALONG WITH THE NBM AND
WPC PRODUCT CONTINUITY WAS USED FOR THE PERIOD FROM
MONDAY-WEDNESDAY TO PRODUCE MAX DETAIL CONSISTENT WITH A PATTERN
WITH SEEMINGLY ABOVE NORMAL PREDICTABILITY. GOING INTO THE LATTER
HALF OF NEXT WEEK, GRADUALLY INCREASING MODEL DIFFERENCES IN THE
WAKE OF THE STRONG LOW FAVORED SOME BLEND INCLUSION OF COMPATIBLE
BUT SMOOTHER INPUT FROM THE GEFS/ECMWF ENSEMBLE MEANS ALONG WITH
THE MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
WITH THE NORTHEAST U.S. STORM SYSTEM MOVING WELL OUT TO SEA BY
MONDAY MORNING, ATTENTION THEN TURNS TO THE DEVELOPING MAJOR LOW
PRESSURE SYSTEM ACROSS THE SOUTH-CENTRAL U.S. THAT HAS BEEN ON THE
UPSTREAM WEATHER HORIZON FOR THE PAST SEVERAL DAYS. CONFIDENCE
CONTINUES TO INCREASE FOR A HIGHLY IMPACTFUL EVENT SPANNING FROM
TEXAS TO THE GREAT LAKES AND NORTHEAST U.S. NEXT WEEK AS THE
SURFACE LOW BECOMES ANOMALOUSLY STRONG OVER ARKANSAS AND THEN
LIFTS NORTHEAST TOWARDS THE EASTERN GREAT LAKES BY WEDNESDAY
MORNING. HEAVY RAINFALL WILL INDEED BE ONE OF THE THINGS MAKING
WEATHER HEADLINES AS A VERY STRONG LOW LEVEL JET ADVECTS DEEP GULF
OF MEXICO MOISTURE NORTHWARD ACROSS THE CENTRAL GULF COAST REGION
ON MONDAY, AND WITH THE POTENTIAL FOR 2 TO 4+ INCHES OF RAINFALL
FROM MULTIPLE ROUNDS OF CONVECTION, A SLIGHT RISK REMAINS
WARRANTED FOR THE NEW DAY 4 ERO FOR MONDAY FROM SOUTHERN LOUISIANA
TO THE FLORIDA PENINSULA, WHERE HOURLY RAINFALL RATES COULD EASILY
EXCEED ONE INCH PER HOUR. THE SLIGHT RISK AREA WAS ALSO EXPANDED A
BIT FARTHER INLAND GIVEN QPF SIGNALS.
THE HEAVY RAINFALL THREAT CONTINUES GOING INTO DAY 5 ON TUESDAY
INTO WEDNESDAY WITH WIDESPREAD 2-3+ INCH RAINFALL TOTALS LIKELY
FROM THE SOUTHERN APPALACHIANS TO SOUTHERN NEW ENGLAND. AN
EXPANSIVE SLIGHT RISK AREA IS NOW PLANNED FROM EXTREME NORTHEAST
GEORGIA THROUGH THE MID-ATLANTIC TO THE NORTHEAST. A STRONG
SOUTHEASTERLY LOW LEVEL JET WILL ADVECT HIGHLY ANOMALOUS MOISTURE
INLAND, ESPECIALLY INTO TERRAIN AND RESULT IN ENHANCED RAINFALL
TOTALS AND RATES FOR THESE AREAS, INCREASING THE THREAT OF
FLOODING PROBLEMS. A MODERATE RISK AREA WAS INTRODUCED FROM
EXTREME EASTERN PA AND NORTHERN NEW JERSEY INTO SOUTHEAST NEW
YORK, WHERE THERE IS A STRONG SIGNAL FOR 2 TO 4 INCH RAINFALL
TOTALS DURING THIS TIME WITH IMPRESSIVE IVT VALUES EXPECTED AS
ADDITIONAL/LEAD ATLANTIC MOISTURE INFLUX GROWS. A BROADER MARGINAL
RISK AREA INCLUDES ALL AREAS FROM SOUTHERN GEORGIA TO SOUTHERN NEW
HAMPSHIRE. ANTECEDENT/FORECAST WET CONDITIONS AND MELTING SNOWS AS
APPLICABLE WILL ALSO PLAY A FACTOR.
IN ADDITION TO THE HEAVY RAINFALL WILL BE THE INCREASING THREAT OF
STRONG TO SEVERE THUNDERSTORMS IN THE WARM SECTOR OF THE LOW WHERE
THE BEST COMBINATION OF KINEMATICS AND INSTABILITY WILL EXIST, AND
THIS IS EXPECTED FROM THE CENTRAL GULF COAST TO THE COASTAL
PORTION OF THE CAROLINAS ON MONDAY AND INTO TUESDAY. ON THE
NORTHWEST SIDE OF THE LOW WILL BE THE INCREASING PROSPECTS FOR AN
IMPACTFUL WINTER STORM FROM KANSAS TO THE WESTERN GREAT LAKES, AND
GIVEN THE STRONG PRESSURE GRADIENT EXPECTED, SOME BLIZZARD
CONDITIONS ARE EXPECTED. WIDESPREAD WINDY CONDITIONS ARE EXPECTED
ACROSS MUCH OF THE EASTERN HALF OF THE NATION TUESDAY AND GOING
INTO WEDNESDAY AS THE SURFACE LOW LIKELY DROPS BELOW 980 MB.
IN TERMS OF TEMPERATURES, AN ARCTIC BLAST FORECAST WITH DEEPEST
FOCUS FOR THE NORTHERN PLAINS TO CLOSE OUT NEXT WEEK WITH
WIDESPREAD SUBZERO LOWS FOR THE DAKOTAS AND INTO MONTANA, AND
HIGHS ONLY IN THE 0S AND 10S FOR MANY OF THOSE SAME AREAS, WITH
ANOMALIES UPWARD TO 30 DEGREES BELOW NORMAL.
UPSTREAM, A CONTINUED SERIES OF HIGHLY DYNAMIC PACIFIC SYSTEMS
WILL MAINTAIN AND PERIODICALLY REJUVENATE A HIGHLY
UNSETTLED/WINTRY NEXT WEEK FOR A GOOD PORTION OF THE WEST. THERE
IS A MODERATE TO LOCALLY HEAVIER PRECIPITATION SIGNAL FOCUS TO
SPREAD DOWN FROM THE PACIFIC NORTHWEST TO NORTH-CENTRAL CALIFORNIA
INTO THE SIERRA. THERE SHOULD ALSO BE WIDESPREAD TERRAIN/MOUNTAIN
FOCUSING SNOWS FURTHER INLAND ACROSS THE INTERMOUNTAIN WEST INTO
THE ROCKIES WITH CONTINUED SYSTEM PROGRESSIONS.
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 FORECAST, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY
MESSAGES 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
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page