868
FXUS02 KWBC 260700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST WED FEB 26 2025
VALID 12Z SAT MAR 01 2025 - 12Z WED MAR 05 2025
..OVERVIEW
THE UPCOMING MEDIUM RANGE PERIOD CONTINUES TO FEATURE A RATHER
PROGRESSIVE OVERALL UPPER FLOW PATTERN. TROUGHING OVER THE EAST
WILL BE ESTABLISHED THIS WEEKEND, BUT SHOULD SHIFT EASTWARD EARLY
NEXT WEEK AND REPLACED BY UPPER RIDGING. MEANWHILE, A CUTOFF UPPER
LOW OVER SOUTHERN CALIFORNIA ON SATURDAY WILL DRIFT EAST AND GET
ABSORBED INTO THE LARGER SCALE FLOW NEXT WEEK OVER THE SOUTHERN
PLAINS. BEHIND THIS, ANOTHER DEEP TROUGH OR UPPER LOW WILL MOVE
INTO THE WEST COAST SUNDAY INTO MONDAY, WITH GENERAL INDICATIONS OF
A MORE AMPLIFIED PATTERN OVER THE WEST TO CENTRAL U.S. NEXT WEEK
AND INCREASING PRECIPITATION FOR MUCH OF THE SOUTH-CENTRAL STATES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
RECENT GUIDANCE CYCLES CONTINUE TO SHOW GOOD AGREEMENT ON THE
OVERALL PATTERN PROGRESSION AND DOMINANT FEATURES OF THE MEDIUM
RANGE PERIOD, BUT WITH UNCERTAINTY IN THE DETAILS. THE TWO MAIN
SOURCES OF UNCERTAINTY LIE WITH THE PAIR OF UPPER LOWS THROUGH THE
WESTERN U.S. THIS WEEKEND AND AGAIN NEXT WEEK. THE FIRST, OVER
SOUTHERN CALIFORNIA BY SATURDAY, HAS SHOWN IMPROVED CONSISTENCY IN
THE TIMING, BUT THERE IS STILL VARIABILITY IN THE TRACK. THE LAST
FEW GFS RUNS REMAINS NOTABLY DISPLACED NORTH OF THE UKMET, CMC, AND
ECMWF. ALSO UNCERTAINTY ON HOW FAR NORTHEAST THE LOW LIFTS ACROSS
THE CENTRAL U.S. AND HOW QUICKLY ITS ABSORBED INTO LARGER SCALE
FLOW. FOR THE SECOND TROUGH EARLY NEXT WEEK, THE GUIDANCE AGREES ON
ITS EXISTENCE BUT THERE'S CONSIDERABLE UNCERTAINTY STILL IN THE
TIMING AND EVOLUTION. COMPARED TO 24-HOURS AGO, THE GFS HAS SPED UP
AND IS CLOSER TO CONSENSUS BUT IS STILL ON THE SLOWER SIDE. THE
ECMWF AND CMC RIGHT NOW ARE MOST AGREEABLE WITH THE ENSEMBLE MEANS.
THE WPC BLEND FOR TONIGHT USED A MULTI-MODEL BLEND FOR THIS
WEEKEND, EVENTUALLY TRANSITIONING NEXT WEEK TO A 60/40 SPLIT
ENSEMBLE MEANS/DETERMINISTIC (ECMWF AND CMC). FOR THE OVERLAPPING
DAY 3-6 PERIOD, THIS MAINTAINS GOOD CONTINUITY WITH THE PREVIOUS
WPC FORECAST.
..WEATHER/HAZARDS HIGHLIGHTS
A CLIPPER SYSTEM SHOULD BRING A ROUND OF PRECIPITATION TO THE
GREAT LAKES AND NORTHEAST INTO SATURDAY, WITH MODERATE SNOWFALL
POSSIBLY ENHANCED BY THE LAKE WATERS ACROSS THE UPPER GREAT LAKES,
WITH MIXED PRECIPITATION JUST TO THE SOUTH. A PERIOD OF STRONG AND
GUSTY WINDS MAY LINGER INTO SATURDAY NEAR THE GREAT LAKES ON THE
BACK- SIDE OF THE SYSTEM AS COLD AIR RUSHES IN BEHIND IT.
THE SOUTHERN STREAM UPPER LOW MOVING INTO SOUTHERN CALIFORNIA
SATURDAY AND INLAND MAY LEAD TO LIGHT SHOWERS OVER CALIFORNIA, THE
SOUTHWEST, AND INTO THE SOUTH- CENTRAL U.S., WITH INCREASING RAIN
CHANCES IN THE SOUTHERN PLAINS BY NEXT SUNDAY AS MOISTURE
INCREASES. THERE APPEARS TO BE A BETTER SIGNAL FOR THE
PRECIPITATION TO SPREAD FARTHER EAST/NORTHEAST ACROSS THE SOUTHERN
PLAINS AND EASTWARD EARLY NEXT WEEK. THE NORTHERN STREAM TROUGH
MOVING THROUGH THE EASTERN PACIFIC AND INTO THE WEST NEXT WEEKEND
WILL ALSO BRING PRECIPITATION CHANCES BACK FOR THE WEST COAST,
SPREADING ACROSS THE GREAT BASIN/ROCKIES EARLY NEXT WEEK. AS THIS
TROUGH MOVES INTO THE CENTRAL U.S. AROUND TUESDAY-WEDNESDAY NEXT
WEEK, IT SHOULD TAP MOISTURE FROM THE GULF TO FUEL MORE WIDESPREAD
RAINS ACROSS THE EAST-CENTRAL U.S.. THERE IS THE POTENTIAL FOR
MODERATE TO AT LEAST LOCALLY HEAVY RAINFALL AND WITH AMBIENT MOIST
SOIL CONDITIONS IN SOME AREAS, THIS WILL BE SOMETHING TO WATCH.
MUCH ABOVE NORMAL TEMPERATURES WILL BE WELL ESTABLISHED BY ACROSS
THE WEST AND INTO THE NORTHERN/CENTRAL PLAINS. THE GREATEST
ANOMALIES WILL BE ACROSS THE NORTHERN PLAINS WITH DAYTIME HIGHS 20
TO LOCALLY 30 DEGREES ABOVE NORMAL, WITH 60S FOR HIGHS AS FAR NORTH
AS NEBRASKA/SOUTH DAKOTA. THE ABOVE NORMAL TEMPERATURES WILL
SPREAD SOUTH AND EAST, WITH THE WEST TRENDING COOLER BY EARLY NEXT
WEEK. ACROSS THE EAST, TEMPERATURES WILL VARY BETWEEN NORMAL AND
ABOVE NORMAL INTO SATURDAY, BUT BE MOSTLY BELOW NORMAL SUNDAY AND
MONDAY IN POST-FRONTAL HIGH PRESSURE BEFORE AGAIN MODERATING.
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
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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