425
FXUS02 KWBC 170710
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
210 AM EST MON FEB 17 2025
VALID 12Z THU FEB 20 2025 - 12Z MON FEB 24 2025
..INTENSE CENTRAL TO EASTERN U.S. ARCTIC BLAST THIS WEEK
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM
COMPOSITE OF REASONABLY CLUSTERED MEDIUM TO LARGER SCALE GUIDANCE
OF THE 18 UTC GFS AND THE 12 UTC ECMWF/UKMET/CANADIAN MODELS VALID
FOR THURSDAY AND FRIDAY. OPTED TO SWITCH TO A COMPOSITE OF BEST
CLUSTERED GUIDANCE OF THE 18 UTC GEFS MEAN AND THE 12 UTC
ECMWF/CANADIAN ENSEMBLE MEANS BY NEXT WEEKEND AMID GROWING FORECAST
SPREAD. THE BLEND PROCESS TENDS TO SMOOTH THE INCREASINGLY NUMEROUS
SMALLER SCALE SYSTEM DIFFERENCES OVER TIME AS CONSISTENT WITH
INDIVIDUAL PREDICTABILITY. THIS SOLUTION MAINTAINS GOOD WPC PRODUCT
CONTINUITY AND SEEMS MAINLY IN LINE WITH LATEST 00 UTC GUIDANCE.
..WEATHER/HAZARDS HIGHLIGHTS
AN EXITING COASTAL STORM WITH LIFT ROBUSTLY OFFSHORE THE EAST
COAST THURSDAY AS MAINLY A MARITIME THREAT, BUT HIGH WINDS AND
SURF WILL IMPACT EASTERN NEW ENGLAND ALONG WITH A WRAP-BACK SNOW.
IN THE WAKE OF THIS STORM, QUITE AN IMPRESSIVE ARCTIC AIRMASS IS
TAKING HOLD OVER THE CENTRAL AND EASTERN U.S. THIS WEEK WITH
ADVENT OF STRONG CANADIAN HIGH PRESSURE. ENTRENCHED COLD AIR WILL
MAINTAIN SOME LAKE EFFECT SNOWS AND OFFER A WIDESPREAD EXTREME COLD
THREAT. NUMEROUS RECORD TEMPERATURES ARE LIKELY FROM THE SOUTH-
CENTRAL PLAINS THROUGH THE MID-LOWER MISSISSIPPI VALLEY AND THE
SOUTH. TEMPERATURES ANOMALIES INTO THURSDAY WILL RANGE FROM 30 TO
40 DEGREES BELOW NORMAL OVER THE CENTRAL PLAINS/MID-MISSISSIPPI
VALLEY, WITH WIDESPREAD VALUES 10-20 DEGREES BELOW NORMAL OVER MUCH
OF THE CENTRAL AND EASTERN U.S. THE AIRMASS WILL SLOWLY MODERATE
LATE WEEK THROUGH NEXT WEEKEND. WHILE NO STRONGLY ORGANIZED STORM
SYSTEM IS EVIDENT THURSDAY THROUGH NEXT MONDAY, THE APPROACH OF
SEVERAL UNCERTAIN IMPULSES MAY PRODUCE SOME LIGHT AND UNHERALDED
BUT LOCALLY DISRUPTIVE WINTRY WEATHER IN THE ARCTIC AIRMASS.
PERIODIC MODERATE RAINFALL IS MORE LIKELY OVER THE GULF IN CLOSER
PROXIMITY TO A PERSISTENT AND SLOW MOVING/WAVY FRONTAL ZONE THOUGH
THIS FORECAST PERIOD, BUT WILL WITH MORE UNCERTAINTY ALSO TRY TO
WORK ONSHORE INTO THE GULF COAST STATES.
UPSTREAM, SEVERAL ORGANIZED SHORTWAVES/FRONTAL SYSTEMS WILL DIG
THROUGH THE WEST LATER THIS WEEK. A MAIN LEAD SYSTEM IN THIS
PERIOD WILL BRING A SWATH OF TERRAIN/MOUNTAIN ENHANCED SNOW
THURSDAY OVER THE NORTH-CENTRAL INTERMOUNTAIN WEST/ROCKIES. THE
PATTERN BECOMES INCREASINGLY FAVORABLE FOR LONGER FETCH MOISTURE
FEED TO FUEL ROUNDS OF MODERATE TO HEAVY LOW ELEVATION RAIN AND
MOUNTAIN SNOW PRIMARILY INTO THE PACIFIC NORTHWEST, BUT ALSO INLAND
TO THE NORTHERN ROCKIES NEXT WEEKEND INTO EARLY NEXT WEEK.
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 (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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page