513
FXUS02 KWBC 281855
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
154 PM EST SAT JAN 28 2023
VALID 12Z TUE JAN 31 2023 - 12Z SAT FEB 04 2023
...NOTABLE PRECIPITATION LIKELY NEXT 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 AND UPPER MIDWEST AT TIMES THROUGH NEXT
WEEK...
..OVERVIEW
IT REMAINS THE CASE THAT PERIODS OF TROUGHING ARE LIKELY THROUGH
MUCH OF THE NORTHERN U.S. NEXT 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. DURING
THE FIRST HALF OF THE WEEK, WITH SIGNIFICANT COLD EXTENDING INTO
THE NORTHEAST FOR THE LATTER HALF OF NEXT WEEK. MEANWHILE A
RIDGE/UPPER HIGH OVER CUBA DURING MUCH OF NEXT 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 TUESDAY
(WITH SOME RAIN AND HIGHER ELEVATION SNOW THERE) 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 POSSIBLY HEAVY
RAIN 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 WPC MEDIUM RANGE PRODUCT SUITE IS PRIMARILY DERIVED FROM A
COMPOSITE BLEND OF REASONABLY WELL CLUSTERED GUIDANCE FROM THE 00
UTC GFS/ECMWF/UKMET/CANADIAN VALID TUE-THU IN A PATTERN WITH ABOVE
NORMAL PREDICTABILITY. THE 06 UTC GFS BECAME LESS ALIGNED WITH THE
PROGRESSION OF EMBEDDED SYSTEMS, ESPECIALLY BY LATER NEXT WEEK,
BUT 12 UTC GUIDANCE HAS TRENDED BACK MORE IN LINE WITH THE
COMPOSITE SOLUTION THAT ALSO HAS DECENT ENSEMBLE AND NATIONAL
BLEND OF MODELS SUPPORT. DESPITE OVERALL FLOW SIMILARITIES, SOME
MINORITY INSERTION OF GEFS/ECMWF ENSEMBLE MEAN GUIDANCE INTO THE
WPC BLEND SEEMED REASONABLE BY FRIDAY/NEXT SATURDAY TO MITIGATE
GROWING SHORTWAVE DIFFERENCES. THIS SOLUTION MAINTAINS DECENT
OVERALL WPC PRODUCT CONTINUITY.
..WEATHER/HAZARD HIGHLIGHTS
THE UPPER TROUGH/LOW ATOP THE SOUTHWEST ON TUESDAY COULD PRODUCE
SOME RAIN AND HIGHER ELEVATION SNOW THERE LINGERING FROM THE SHORT
RANGE PERIOD. THEN THIS FEATURE AND THE OVERALL TROUGH AND OTHER
SHORTWAVES 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 COULD LEAD TO
MULTIPLE ROUNDS OF 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 A SLIGHT RISK IS IN PLACE IN WPC'S
EXPERIMENTAL EXCESSIVE RAINFALL OUTLOOK FOR DAY 5/WEDNESDAY GIVEN
GOOD UPPER-LEVEL SUPPORT, NAMELY EXCELLENT DIFLUENCE/DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF THE JET, AND SOMEWHAT WET ANTECEDENT
CONDITIONS. THE LATEST RENDITION HAS BEEN SHIFTED SLIGHTLY
WESTWARD FROM WPC OVERNIGHT CONTINUITY IN LINE WITH GUIDANCE
TRENDS. QPF IN THIS REGION HAS INCREASED IN BOTH THE NBM AND EVEN
SLIGHTLY MORE FROM WPC GIVEN BETTER 00 UTC MODEL AGREEMENT AND
SLIGHTLY SLOWER TREND. 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. ELSEWHERE, PERIODS OF LAKE EFFECT SNOW ARE POSSIBLE TO
THE LEE OF THE NORTHERN/EASTERN GREAT LAKES. SOME LIGHT
PRECIPITATION IS POSSIBLE IN THE NORTHWEST ON TUESDAY, BUT MORE
LIMITED TO WESTERN WASHINGTON BY WEDNESDAY. THE WEST COAST COULD
SEE INCREASING PRECIPITATION CHANCES BY THE LATTER HALF OF 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.
VERY COLD CONDITIONS OVER THE NORTH-CENTRAL U.S. DURING THE SHORT
RANGE PERIOD WILL CONTINUE INTO NEXT WEEK, IN THE WAKE OF A STRONG
COLD FRONT PRODUCING A SURGE OF ARCTIC AIR. HIGHS IN THE SINGLE
DIGITS AND EVEN AT OR BELOW ZERO ARE POSSIBLE IN THE DAKOTAS INTO
MINNESOTA WHILE BITTERLY COLD LOWS COMBINED WITH WIND WILL PRODUCE
DANGEROUS WIND CHILLS. MUCH BELOW NORMAL TEMPERATURES SHOULD
EXTEND ACROSS MUCH OF THE CENTRAL U.S. THROUGH MIDWEEK ESPECIALLY,
AS WELL AS ACROSS MUCH OF THE INTERIOR WEST WITH TEMPERATURES
15-25F BELOW NORMAL THROUGH TUESDAY 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. A
FEW RECORD HIGHS ARE POSSIBLE TUESDAY-WEDNESDAY. WHILE THE
WESTERN/CENTRAL U.S. MODERATES LATER IN THE WEEK, THE EAST WILL
TREND SOMEWHAT COLDER WITH NEW ENGLAND POSSIBLY SEEING HIGHS
10-20F BELOW NORMAL BY NEXT FRIDAY.
TATE/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, 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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