319
FXUS02 KWBC 151958
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 PM EST THU JAN 15 2026
VALID 12Z SUN JAN 18 2026 - 12Z THU JAN 22 2026
***HEAVY LAKE EFFECT SNOWS ARE LIKELY FOR THE FIRST HALF OF NEXT
WEEK FROM MICHIGAN TO UPSTATE NEW YORK***
20Z UPDATE: THE 12Z MODEL GUIDANCE SUITE REMAINS IN VERY GOOD
AGREEMENT OVERALL FOR SUNDAY INTO EARLY NEXT WEEK, WITH A
DETERMINISTIC MODEL BLEND USED AS A STARTING POINT FOR FRONTS AND
PRESSURES. IN TERMS OF QPF, THE NBM HAD A REASONABLE DEPICTION OF
QPF FOR MOST AREAS, BUT PROBABLY TOO LIGHT WITH LAKE EFFECT SNOW
BANDS, SO QPF WAS RAISED A LITTLE FROM MICHIGAN TO UPSTATE NEW YORK
TO BETTER ACCOUNT FOR THIS, WITH AREAS DOWNWIND OF LAKE ONTARIO
POTENTIALLY GETTING 1-2+ FEET OF ACCUMULATION. FOR THE COASTAL LOW
ON SUNDAY, THE MODELS HAVE FOR THE MOST PART STABILIZED WITH THE
QPF MAINLY CONFINED TO THE COASTAL PLAIN OF THE CAROLINAS AND
SOUTHEAST VIRGINIA, AND THE GFS HAS TRENDED CLOSER TO THE ECMWF
OVER THE PAST FEW MODEL CYCLES. THE SHORTWAVE THAT APPROACHES FROM
THE WEST DOES NOT ACQUIRE NEGATIVE TILT UNTIL AFTER IT EXITS THE
EAST COAST, AND THIS LIMITS THE POTENTIAL FOR A MORE IMPACTFUL
WINTER STORM. TOWARDS THE END OF THE FORECAST PERIOD THURSDAY, THE
OVERALL FLOW PATTERN BECOMES A LITTLE MORE ZONAL COMPARED TO
EARLIER IN THE WEEK, AND MODEL DIFFERENCES BECOME MORE APPARENT, SO
THE ENSEMBLE MEANS WERE INCREASED TO ABOUT 40% BY THAT TIME. THE
PREVIOUS FORECAST DISCUSSION IS APPENDED BELOW FOR REFERENCE.
/HAMRICK
-----------------
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE VERY AMPLIFIED PATTERN OF A RIDGE UP THE WEST COAST INTO
SOUTHEAST ALASKA WITH A DEEP LOW OVER HUDSON BAY AND ASSOCIATED
TROUGHING EAST OF THE ROCKIES PERSISTS INTO NEXT WEEK. THROUGH THE
MIDDLE OF NEXT WEEK INDICATIONS ARE THAT THE RIDGE WILL SHIFT OFF
THE WEST COAST (AND INTO MAINLAND ALASKA) AS THE SPRAWLING LOW
FURTHER EXPANDS. THE SERIES OF SHORTWAVE TROUGHS ROUNDING THE
HUDSON BAY LOW WILL REMAIN KEY FOR FORECAST AGREEMENT. THE WPC DAYS
3-7 SURFACE PRESSURES AND FRONTS FORECAST WAS BASED ON A BLEND
THAT MOST RESEMBLED THE 18Z EC-AIFS WHICH BY DAY 4 WAS MAINLY THE
EC AND THE ECENS MEAN.
LOW QPF BIAS IN THE 01Z NBM V4.3 QPF WAS MITIGATED USING THE 18Z EC-
AIFS, 12Z ECMWF, AND THE NBM V5.0 WITH SOME 18Z GFS TO ENHANCE LAKE
EFFECT PRECIP AND 12Z CMC FOR LOWER TX GULF COAST RAINFALL STARTING
ON TUESDAY.
..WEATHER/HAZARDS HIGHLIGHTS
HEAVY RAINFALL REMAINS LIMITED OVER THE CONUS UNTIL WESTERN GULF
LOW PRESSURE/FRONTAL PATTERN ALLOWS SOUTHERN/COASTAL TEXAS TO SEE
SOME HEAVIER RAIN STARTING ON TUESDAY. THE DAYS 4/5 EROS REMAIN
NIL.
A BAROCLINIC LEAF DEVELOPING OVER THE SOUTHEAST EARLY SUNDAY
INTENSIFIES THROUGH THE DAY WITH LOW PRESSURE DEVELOPING OFF THE
EASTERN SEABOARD. BACKSIDE PRECIP LOOKS TO BE SNOW OVER INTERIOR
LOCATIONS OF THE SOUTHEAST AND ALONG THE MID-ATLANTIC/NORTHEAST
COASTS. MEANWHILE A POTENT NORTHERN STREAM REINFORCING TROUGH
SWINGS ACROSS THE NORTHERN PLAINS AND GREAT LAKES SUNDAY THROUGH
MONDAY. POWERFUL WINDS WILL ACCOMPANY THIS OVER THE NORTHERN PLAINS
WITH LAKE EFFECT/ENHANCED SNOWFALL. THE NEXT WAVE OVER THE NORTHERN
PLAINS/GREAT LAKES LOOKS TO BE TUESDAY AFTERNOON THROUGH WEDNESDAY
NIGHT WITH ADDITIONAL LES. WEST GULF TROUGHING ALLOWS CONVERGENCE
OVER THE LOWER TX COAST STARTING ON TUESDAY, PERHAPS PEAKING ON
THURSDAY.
WELL BELOW AVERAGE TEMPERATURES ARE EXPECTED FOR THE EASTERN
PORTION OF THE LOWER 48 SUNDAY BEHIND THE TROUGH CAUSING THE
OFFSHORE LOW PRESSURE DEVELOPMENT. RATHER BELOW NORMAL
TEMPERATURES THEN CROSS THE UPPER MIDWEST MONDAY AND OHIO
VALLEY/EASTERN U.S. TUESDAY. THE RIDGING OVER THE WEST COAST
MAINTAINS ABOVE NORMAL TEMPERATURES ROCKIES AND WEST THROUGH THE
MIDDLE OF NEXT WEEK WITH THE FOCUS OF THE ANOMALY SHIFTING FROM
THE WEST COAST TO THE INTERMOUNTAIN WEST EARLY NEXT WEEK.
JACKSON
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 (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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
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