950
FXUS02 KWBC 011904
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
203 PM EST WED FEB 01 2023
VALID 12Z SAT FEB 04 2023 - 12Z WED FEB 08 2023
...TEMPERATURES SATURDAY ACROSS THE NORTHEAST WILL BE DANGEROUSLY
COLD TEMPERATURES...
..OVERVIEW
THE OVERALL UPPER-LEVEL PATTERN DURING THE MEDIUM RANGE PERIOD
WILL REMAIN FAIRLY WAVY AND PROGRESSIVE. AS THE PERIOD BEGINS
SATURDAY, TROUGHING WILL EXTEND FROM A DEEP UPPER LOW OVER THE
CANADIAN MARITIMES INTO THE NORTHEAST, LEADING TO SIGNIFICANTLY
COLD TEMPERATURES AND WIND CHILLS THERE. ANOTHER TROUGH IS
FORECAST TO PRESS ACROSS THE CENTRAL TO EASTERN U.S. THROUGH EARLY
NEXT WEEK, BUT WITH PRECIPITATION LIMITED TO THE GREAT LAKES
REGION AND PERHAPS THE EASTERN SEABOARD. YET ANOTHER TROUGH
APPROACHING THE WEST SHOULD LEAD TO A WETTER PATTERN THERE FOR THE
WEEKEND, WITH GENERALLY LIGHT TO MODERATE RAIN AND SNOW AMOUNTS.
THIS LATTER TROUGH IS FORECAST TO TRACK INTO THE CENTRAL U.S. IN
SOME FASHION BY TUESDAY-WEDNESDAY, LEADING TO A WETTER PATTERN
THERE.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST SUITE OF MODEL GUIDANCE MAINTAINS DECENT AGREEMENT ON
THE LARGE SCALE PATTERN FOR THE WEEKEND/START OF THE EXTENDED
PERIOD. OVER THE WEEKEND AN UPPER TROUGH WILL BE TRACKING OFFSHORE
THE NORTHEAST REGION, IMPULSES EXITING THE ROCKIES INTO THE PLAINS
WHILE TROUGH APPROACHES THE WEST. THE TROUGH ENTERING THE WEST HAS
BEEN AND CONTINUES TO BE THE MAIN FEATURE WHERE THE MODELS ARE
WAFFLING ON THE DEGREE OF SEPARATION OF THE NORTHERN AND SOUTHERN
STREAMS WHICH HAS LED TO TIMING, STRENGTH, LOCATION AND
PROGRESSION DIFFERENCES PARTICULARLY FOR THE SOUTH FOR THE LATER
PORTION OF THE EXTENDED PERIOD. A MAJORITY OF THE GUIDANCE HAVE
CONVERGED TO A SOLUTION WITH A CLOSED LOW OVER THE SOUTHWEST THAT
WILL LINGER FOR AWHILE. WHILE THE CMC LEANS TOWARD THIS PATTERN IT
QUICKLY MOVES TO THE FRONT OF THE CLUSTER AND FAVORS A FASTER
TRACK ACROSS THE SOUTHERN PLAINS THROUGH THE MIDDLE AND LATTER
PORTION OF THE EXTENDED; THUS ITS INCLUSION WAS LIMITED. BOTH THE
GEFS MEANS AND THE EC ENSEMBLE MEANS HAD SOLUTIONS SIMILAR TO
THEIR RESPECTIVE PARENT MODELS BUT SLIGHTLY MORE PROGRESSIVE
ACROSS THE SOUTHWEST. THERE CONTINUES TO BE SOME DIFFERENCES IN
THE MODELS REGARDING WHETHER ADDITIONAL ENERGY COMING FROM THE
NORTHWEST INTERACTS WITH THE TROUGH, WHICH COMPLICATES MATTERS ALL
THE MORE.
THE PREFERRED WPC BLEND UTILIZED A BLEND OF THE 00Z/06Z GFS/00Z
ECWMF WITH LESSER WEIGHTINGS OF THE CMC AND UKMET. THE INCLUSION
OF THE THE ENSEMBLE MEANS BEGAN BY DAY AND INCREASED TO NEARLY 50%
WEIGHTING BY THE END OF THE EXTENDED FORECAST.
..WEATHER/HAZARD HIGHLIGHTS
VERY CHILLY CONDITIONS ARE EXPECTED ACROSS THE NORTHEAST SATURDAY
AS COLD AIR AND GUSTY WINDS SETTLE IN UNDER UPPER-LEVEL TROUGHING.
DANGEROUS WIND CHILLS AND POSSIBLY NEW DAILY TEMPERATURE RECORDS
ARE IN STORE FOR MUCH OF THE NORTHEAST REGION. TEMPERATURES COULD
STAY BELOW ZERO ALL DAY IN PARTS OF MAINE AND IN THE SINGLE DIGITS
IN MUCH OF NORTHERN NEW ENGLAND. THIS COLD AIRMASS IS EXPECTED TO
SINK FURTHER SOUTH ALONG THE EASTERN SEABOARD LEADING TO
TEMPERATURES 10-20F BELOW NORMAL. TEMPERATURES ARE EXPECTED TO
REBOUND ACROSS THE EAST WAS WARMER TEMPERATURES OVER THE CENTRAL
U.S. MIGRATE EASTWARD AFTER THE WEEKEND.THE WEST HOWEVER COULD
STAY AROUND 5-10F BELOW AVERAGE ESPECIALLY IN TERMS OF HIGHS
UNDERNEATH UPPER TROUGHING.
A FRONTAL SYSTEM COULD SPREAD SOME LIGHT SNOW TO THE MIDWEST/GREAT
LAKES REGIONS AND NORTHEAST THIS WEEKEND, AND AMOUNTS COULD BE
ENHANCED DOWNWIND OF THE GREAT LAKES. LIGHT PRECIPITATION IS
POSSIBLE ALONG THE EASTERN SEABOARD WITH SOME MOISTURE RETURN BY
SUNDAY, BUT UNCERTAINTY REMAINS AS TO HOW MUCH FALLS ONSHORE.
MEANWHILE IN THE WEST, GENERALLY LIGHT TO MODERATE PRECIPITATION
IS EXPECTED THIS WEEKEND IN THE FORM OF LOWER ELEVATION RAIN AND
HIGHER ELEVATION SNOW, WITH TYPICAL TERRAIN ENHANCEMENT ACROSS THE
COASTAL RANGES AND THE SIERRA NEVADA. SNOW IS FORECAST TO SPREAD
INTO THE INTERMOUNTAIN WEST AND ROCKIES EARLY NEXT WEEK, AND THEN
PRECIPITATION COULD OVERSPREAD THE CENTRAL U.S. BY MONDAY-TUESDAY
ALONG AND AHEAD OF A LOW PRESSURE/FRONTAL SYSTEM. GENERALLY THIS
LOOKS TO BE IN THE FORM OF RAIN OTHER THAN SOME POSSIBLE SNOW IN
THE NORTHERN TIER (MIDWEST-GREAT LAKES), BUT WILL CONTINUE TO
MONITOR. THE PACIFIC NORTHWEST TO NORTHERN ROCKIES ARE LIKELY TO
SEE ADDITIONAL ROUNDS OF PRECIPITATION INTO THE FIRST HALF OF NEXT
WEEK.
CAMPBELL/TATE
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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