069
FXUS02 KWBC 290657
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
156 AM EST SUN JAN 29 2023
VALID 12Z WED FEB 01 2023 - 12Z SUN FEB 05 2023
...NOTABLE PRECIPITATION LIKELY FOR THE LATTER HALF OF THE WEEK
INCLUDING HEAVY RAIN IN THE SOUTH-CENTRAL TO SOUTHEASTERN U.S.
WITH FREEZING RAIN/SNOW ON THE NORTHERN SIDE...
...DANGEROUSLY COLD TEMPERATURES AND WIND CHILLS ARE FORECAST
ACROSS THE NORTHERN PLAINS/UPPER MIDWEST AND INTO THE NORTHEAST AT
TIMES THROUGH THE WEEK...
..OVERVIEW
IT REMAINS THE CASE THAT PERIODS OF TROUGHING ARE LIKELY THROUGH
MUCH OF THE NORTHERN U.S. THIS WEEK EXTENDING FROM A PERSISTENT
HUDSON BAY CLOSED LOW, LEADING TO COLDER THAN AVERAGE TEMPERATURES
FOR MUCH OF THE NORTHERN TIER. THE COLD TEMPERATURES AND WIND
CHILLS COULD BE MOST HAZARDOUS FOR THE NORTH-CENTRAL U.S. THROUGH
AROUND FRIDAY, WITH SIGNIFICANT COLD EXTENDING INTO THE NORTHEAST
BY LATE WEEK. MEANWHILE A RIDGE/UPPER HIGH OVER CUBA DURING MUCH
OF THE WEEK SHOULD KEEP THE SOUTHEAST WARMER THAN NORMAL. BETWEEN
THESE UPPER-LEVEL FEATURES AND TEMPERATURE REGIMES, EXPECT ACTIVE
WEATHER AS A SOUTHERN STREAM UPPER TROUGH/LOW EJECTS FROM THE
SOUTHWEST AND TRACKS ACROSS THE CENTRAL/SOUTHERN TIER OF THE
CONUS. THIS COMBINED WITH A COUPLE WAVY FRONTS ALONG WITH PERIODS
OF GULF INFLOW WILL SUPPORT A COUPLE OF SIGNIFICANT PRECIPITATION
EVENTS WITH HEAVY RAIN AND POSSIBLE FLOODING TO THE
SOUTH/SOUTHEAST AND WINTRY WEATHER IN THE COLDER AIR. LATER IN THE
WEEK, THE WEST COAST MAY SEE INCREASING PRECIPITATION CHANCES WITH
THE APPROACH OF AN EASTERN PACIFIC UPPER TROUGH.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST COUPLE OF MODEL CYCLES HAVE BEEN GENERALLY AGREEABLE
WITH THE OVERALL PATTERN, INCLUDING THE SOUTHERN STREAM UPPER LOW
CENTERED AROUND NORTHWESTERN MEXICO AS THE PERIOD BEGINS WEDNESDAY
AND ITS TRACK AND TIMING AS IT EJECTS EASTWARD, MAINTAINING A BIT
OF SEPARATION WITH THE NORTHERN STREAM TROUGH LIKELY THROUGH
FRIDAY. BEHIND THESE FEATURES MODELS AGREE REGARDING A PERIOD OF
UPPER RIDGING SHIFTING ACROSS THE WEST WEDNESDAY-THURSDAY AND INTO
THE CENTRAL U.S. LATE THIS WEEK. TROUGHY FLOW COMING FROM THE
PACIFIC INTO THE WEST SHOWS A BIT MORE MODEL VARIATIONS THOUGH.
GFS RUNS HAVE BEEN ON THE FASTER SIDE OF THE GUIDANCE ENVELOPE
WHILE THE ECMWF AND CMC WERE SLOWER, WITH A FAIR AMOUNT OF SPREAD
IN THE ENSEMBLE MEMBERS. A MIDDLE GROUND SOLUTION NOT AS FAST AS
THE 12/18Z GFS SEEMS BEST AT THIS TIME. THE GENERAL IDEA SHOWS
THIS TROUGH REACHING THE EAST-CENTRAL U.S. BY NEXT SUNDAY WITH
ANOTHER RIDGE AXIS BEHIND IT. FOR THIS PROGRESSIVE WAVY AND FAIRLY
AGREEABLE PATTERN, THE WPC FORECAST UTILIZED A MULTI-MODEL
DETERMINISTIC BLEND EARLY ON WITH SOME INCORPORATION OF THE
ENSEMBLE MEANS FOR THE LATTER HALF OF THE PERIOD. GOOD CONTINUITY
WITH THE PREVIOUS FORECAST WAS MAINTAINED.
..WEATHER/HAZARD HIGHLIGHTS
THE SOUTHERN STREAM UPPER TROUGH/LOW TRACKING ACROSS THE SOUTHERN
U.S. AND THE BROADER NORTHERN STREAM TROUGH WILL PROVIDE SUPPORT
FOR FRONTAL BOUNDARIES WITH WAVES OF LOW PRESSURE THROUGH THE
SOUTH-CENTRAL TO SOUTHEASTERN U.S., WHICH COMBINED WITH GULF
MOISTURE STREAMING IN WILL LEAD TO WIDESPREAD PRECIPITATION. ON
THE SOUTHERN SIDE LOCALLY HEAVY RAIN IS EXPECTED, WHICH COULD
CAUSE LOCALIZED FLOODING ESPECIALLY AT TIMES WHEN THERE IS
SUFFICIENT INSTABILITY FOR HIGHER RAIN RATES. AT THIS TIME SLIGHT
RISKS ARE IN PLACE IN WPC'S EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK FOR BOTH DAY 4/WEDNESDAY FROM EASTERN TEXAS INTO THE LOWER
MISSISSIPPI VALLEY AND DAY 5/THURSDAY STRETCHING INTO THE
SOUTHEAST GIVEN GOOD UPPER-LEVEL SUPPORT, NAMELY EXCELLENT
DIFLUENCE/DIVERGENCE IN THE RIGHT ENTRANCE REGION OF THE JET, AS
IT TRACKS EASTWARD. THEN ON THE NORTHERN SIDE OF THE PRECIPITATION
CHANCES, THERE IS POTENTIAL FOR SNOW ACROSS PARTS OF THE SOUTHERN
HALF OF THE PLAINS AND MISSISSIPPI VALLEY INTO THE OHIO/TENNESSEE
VALLEYS AND THE MID-ATLANTIC AT TIMES, BUT LOW CONFIDENCE
CONTINUES IN THE SPECIFICS. THIS IS ALSO A PATTERN THAT COULD
SUPPORT FREEZING RAIN WITH ICE ACCUMULATIONS WITH THE COLD AIR IN
PLACE AT THE SURFACE AND POTENTIAL FOR WARM MOIST AIR TO FLOW
OVERTOP IT. THE PLACEMENT OF HEAVIEST RAIN, FREEZING RAIN, AND
SNOW ALL REMAIN IN QUESTION AS SMALL-SCALE DETAILS LIKE SURFACE
FRONTAL POSITIONS AND LATE WEEK SHORTWAVE SPECIFICS REMAIN
UNCERTAIN. DRIER CONDITIONS ARE LIKELY FOR THE EAST BY SATURDAY.
ELSEWHERE, PERIODS OF LAKE EFFECT SNOW ARE POSSIBLE TO THE LEE OF
THE NORTHERN/EASTERN GREAT LAKES. THE WEST COAST COULD SEE
INCREASING PRECIPITATION CHANCES BY LATER IN THE WEEK BUT WITH
UNCERTAINTY OVER THE SOUTHWARD EXTENT AND AMOUNTS. CURRENTLY THE
BEST POTENTIAL FOR AT LEAST SOME RAIN/MOUNTAIN SNOW IS OVER THE
PACIFIC NORTHWEST WITH MOISTURE POSSIBLY EXTENDING AS FAR SOUTH AS
NORTHERN CALIFORNIA, AND AS FAR EAST AS THE NORTHERN ROCKIES.
VERY COLD CONDITIONS OVER THE NORTH-CENTRAL U.S. DURING THE SHORT
RANGE PERIOD COULD CONTINUE INTO THE LATTER PART OF THE WEEK,
UNDERNEATH INSTANCES OF COLD UPPER TROUGHING. HIGHS IN THE SINGLE
DIGITS ARE POSSIBLE IN THE DAKOTAS INTO MINNESOTA WHILE BITTERLY
COLD LOWS COMBINED WITH WIND WILL PRODUCE DANGEROUS WIND CHILLS.
MUCH BELOW NORMAL TEMPERATURES THEN SHIFT INTO THE NORTHEAST BY
LATE WEEK, WITH THE POSSIBILITY OF HIGHS BELOW ZERO IN NORTHERN
NEW ENGLAND BY SATURDAY. TEMPERATURES ARE EXPECTED TO BE GENERALLY
BELOW NORMAL ACROSS MUCH OF THE INTERIOR WEST AND CENTRAL U.S.
AROUND MIDWEEK WITH GRADUAL MODERATION THEREAFTER. MEANWHILE THE
FAR SOUTHEAST AND FLORIDA PENINSULA SHOULD SEE THE MOST CONSISTENT
ABOVE AVERAGE TEMPERATURES, WITH HIGHS 10-15F ABOVE AVERAGE AND
PLUS 10-20F ANOMALIES FOR LOWS BEFORE A COOLER TREND NEXT WEEKEND.
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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